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Sample records for cement treated soils

  1. Physical and geotechnical properties of cement-treated clayey soil using silica nanoparticles: An experimental study

    Science.gov (United States)

    Ghasabkolaei, N.; Janalizadeh, A.; Jahanshahi, M.; Roshan, N.; Ghasemi, Seiyed E.

    2016-05-01

    This study investigates the use of nanosilica to improve geotechnical characteristics of cement-treated clayey soil from the coastal area of the eastern Caspian Sea in the Golestan province, Iran. Atterberg limits, unconfined compressive strength, and California bearing ratio (CBR) tests were performed to investigate the soil plastic and strength parameters. The specimens were prepared by mixing soil with 9% cement and various contents of nanosilica. An ultrasonic bath device was used to disperse nanosilica in water. The addition of nanosilica enhanced the strength parameters of the clayey soil. Moreover, a nanosilica percentage of 1.5% by weight of cement improved the compressive strength of the cement-treated clay up to 38%, at age of 28 days. A scanning electron microscope (SEM) and an atomic force microscope (AFM) were used to evaluate specimen morphology. SEM and AFM results confirm the experimental ones. Therefore, nanosilica can be employed for soil improvement in geotechnical engineering.

  2. pH-dependent leaching behaviour and other performance properties of cement-treated mixed contaminated soil

    Institute of Scientific and Technical Information of China (English)

    Reginald B. Kogbara; Abir Al-Tabbaa; Yaolin Yi; Julia A. Stegemann

    2012-01-01

    Portland cement has been widely used for stabilisation/solidification (S/S) treatment of contaminated soils.However,there is a dearth of literature on pH-dependent leaching of contaminants from cement-treated soils.This study investigates the leachability of Cu,Pb,Ni,Zn and total petroleum hydrocarbons (TPH) from a mixed contaminated soil.A sandy soil was spiked with 3000 mg/kg each of Cd,Cu,Pb,Ni and Zn,and 10,000 mg/kg of diesel,and treated with ordinary Portland cement (CEM I).Four different binder dosages,5%,10%,15% and 20% (m/m) and different water contents ranging from 13%-19% dry weight were used in order to find a safe operating envelope for the treatment process.The pH-dependent leaching behaviour of the treated soil was monitored over an 84-day period using a 3-point acid neutralisation capacity (ANC) test.The monolithic leaching test was also conducted.Geotechnical properties such as unconfined compressive strength (UCS),hydraulic conductivity and porosity were assessed over time.The treated soils recorded lower leachate concentrations of Ni and Zn compared to the untreated soil at the same pH depending on binder dosage.The binder had problems with Pb stabilisation and TPH leachability was independent of pH and binder dosage.The hydraulic conductivity of the mixes was generally of the order,10-8 m/sec,while the porosity ranged from 26%-44%.The results of selected performance properties are compared with regulatory limits and the range of operating variables that lead to acceptable performance described.

  3. 水泥冷再生灰土试验研究%Test and Study on Cement Stabled Cold Recycling Lime-Treated Soil

    Institute of Scientific and Technical Information of China (English)

    张倩; 韦华威; 王永兵; 应国强; 胡建林

    2012-01-01

    In this paper, composition design and properties of lime-treated fine-grained soil are studied using series of test such as liquid plastic limit test, compaction test, strength test, contraction test and stability test. Feasibility of recycling old subbase material as lime, cement or lime-fly ash treated fine-grained soil is proved. Test results show that cement stabled recycling lime-treated soil has similar physical properties as typical semi-rigid materials. The recycled material also illustrates good road-use properties and thus is suitable to be used as subbase. This is of important significance both to the comprehensive utilization of cold pavement material and to achievement of the maximum economic and social benefits.%通过一系列室内试验包括液塑限试验、击实试验、强度试验、收缩试验以及稳定性试验研究了水泥再生灰土材料石灰稳定细粒土的材料组成设计及其路用性能,研究了旧路面底基层材料石灰、水泥或二灰稳定细粒土能否通过再生技术进行冷再生.试验结果表明水泥稳定旧路面灰土材料与典型半刚性材料相比具有类似的物理特性,同时也发现冷再生材料具有较好的路用性能,适宜作为道路底基层材料.这对于旧路面材料的综合利用,达到经济效益和社会效益最大化的目标具有重要意义.

  4. Effects of Ground Conditions on Microbial Cementation in Soils

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    Daehyeon Kim

    2013-12-01

    Full Text Available The purpose of this study is to understand the effect of ground conditions on microbial cementation in cohesionless soils. Since the method of microbial cementation is still at the experimental stage, for its practical use in the field, a number of laboratory experiments are required for the quantification of microbial cementation under various ground conditions, such as relative densities, relative compactions and particle size distributions. In this study, in order to evaluate the effectiveness of microbial cementation in treated sands and silts, an experiment was performed for different relative densities of silica sands, for different relative compactions of silts and for different particle size distributions of weathered soils sampled from the field. Scanning electron microscope (SEM, X-ray diffraction (XRD, energy dispersive X-ray (EDX spectroscopy and mapping analyses were implemented for the quantification of the levels of microbial cementations for sand, silt and weathered soil specimens. Based on the test results, a considerable microbial cementation was estimated depending on the soil conditions; therefore, an implementation of this new type of bio-grouting on a weak foundation may be possible to increase the strength and stiffness of weak ground.

  5. Development of Mechanistic-Empirical Pavement Design for Tropical Climate Using Cement-Treated Base Layer

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    O. S. Aderinola

    2016-08-01

    Full Text Available A mechanistic-empirical pavement design method is developed characterising cement-treated base layers for pavement design in Nigeria or other similar tropical and subtropical countries. Asphalt Concrete surface, Subbase and Aggregate base were characterised based on back calculation data from Claros et al (1986 while cement-treated base layer was based on modulus tests that had been conducted by past researchers. Failure criteria for the Asphalt Concrete fatigue failure and the subgrade rutting failure were based on those by Claros and Ijeh (1987 for Nigerian pavements. Cracking criterion used for the cement-treated layer was that developed by Otee et al. (1982. The comparison between the Soil-Cement and Aggregate base showed that at a low Equivalent Single Axle Load (ESAL (0.5 million repetitions was considered, the use of Aggregate base was better than Soil-Cement base. That for Aggregate base and Cement-Treated Gravel Base showed that the Cement-Treated Gravel Base was better than the Aggregate base at high ESAL (2.5 million repetitions was considered

  6. ASSESSMENT OF DEFORMATION AND STRENGTH OF SOILS STRENGTHENED BY CEMENTING

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    Sainov Mihail Petrovich

    2014-09-01

    Full Text Available Currently there are few studies of deformation and strength properties of loose soils strengthened by cementing. Based on the data of already arranged grout curtains it was determined that in cemented gravel-pebble soil there are 7...9 % of cement, which is less than in concrete. To assess deformation and strength of such soils it is possible to use the data of tests conducted by other authors, where the effect of cement contents on sand-cement mix properties was studied. Analysis of experimental data showed that cemented soil may be identified with concrete only with high content of cement (more than 10 %. At cement content 7...9 % in soil the strength deformation of cemented soil varies to a small extent. Its deformation becomes 2-3 times less. It greatly depends on compression stresses. The formulae are proposed which permit assessing the effect of compression and cement content on deformation of cemented soil. It is shown that strength of cemented soil is less than that even of the weakest concrete. It has a sufficiently high cohesion, but the friction angle is approximately the same as that of the initial soil.

  7. Triaxial shear behavior of a cement-treated sandegravel mixture

    Institute of Scientific and Technical Information of China (English)

    Younes Amini; Amir Hamidi

    2014-01-01

    A number of parameters, e.g. cement content, cement type, relative density, and grain size distribution, can influence the mechanical behaviors of cemented soils. In the present study, a series of conventional triaxial compression tests were conducted on a cemented poorly graded sandegravel mixture containing 30%gravel and 70%sand in both consolidated drained and undrained conditions. Portland cement used as the cementing agent was added to the soil at 0%, 1%, 2%, and 3%(dry weight) of sandegravel mixture. Samples were prepared at 70%relative density and tested at confining pressures of 50 kPa, 100 kPa, and 150 kPa. Comparison of the results with other studies on well graded gravely sands indicated more dilation or negative pore pressure in poorly graded samples. Undrained failure envelopes determined using zero Skempton’s pore pressure coefficient ðA ¼ 0Þ criterion were consistent with the drained ones. Energy absorption potential was higher in drained condition than undrained condition, suggesting that more energy was required to induce deformation in cemented soil under drained state. Energy ab-sorption increased with increase in cement content under both drained and undrained conditions.

  8. Experimental study on the electrical resistivity of soil cement admixtures

    Science.gov (United States)

    Liu, Song Yu; Du, Yan Jun; Han, L. H.; Gu, M. F.

    2008-05-01

    Recently in China, soil cement is widely used to improve the soft ground in the highway construction engineering. Literature studies are mainly investigating the mechanical properties of the soil cement, while its properties of the electrical resistivity are not well addressed. In this paper, the properties of the electrical resistivity of the reconstituted soil-cement and the in situ soil cement columns are investigated. The test results show that the electrical resistivity of the soil cement increases with the increase in the cement-mixing ratio and curing time, whereas it decreases with the increase in the water content, degree of saturation and water cement ratio. A simple equation is proposed to predict the electrical resistivity of soil cement under the condition of the specified curing time and water cement ratio. It is found that the electrical resistivity has a good relationship with the unconfined compression strength and blow count of SPT. It is expected that the electrical resistivity method can be widely used for checking/controlling the quality of soil cement in practice.

  9. Laboratory evaluation of cement treated aggregate containing crushed clay brick

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    Liqun Hu

    2014-10-01

    Full Text Available The waste clay bricks from debris of buildings were evaluated through lab tests as environmental friendly materials for pavement sub-base in the research. Five sets of coarse aggregates which contained 0, 25%, 50%, 75% and 100% crushed bricks, respectively, were blended with sand and treated by 5% cement. The test results indicated that cement treated aggregate which contains crushed clay brick aggregate had a lower maximum dry density (MDD and a higher optimum moisture content (OMC. Moreover, the unconfined compressive strength (UCS, resilience modulus, splitting strength, and frost resistance performance of the specimens decreased with increase of the amount of crushed clay brick aggregate. On the other hand, it can be observed that the use of crushed clay brick in the mixture decreased the dry shrinkage strain of the specimens. Compared with the asphalt pavement design specifications of China, the results imply that the substitution rate of natural aggregate with crushed clay brick aggregate in the cement treated aggregate sub-base material should be less than 50% (5% cement content in the mixture. Furthermore, it needs to be noted that the cement treated aggregate which contains crushed clay bricks should be cautiously used in the cold region due to its insufficient frost resistance performance.

  10. Statistical Study on Cement-Soil Mixture Strength

    Institute of Scientific and Technical Information of China (English)

    YU Zhiqiang; CAO Yonghua; YAN Shuwang

    2005-01-01

    This paper presents an investigation on strength of cement deep mixing (CDM) mixture. Four typical works of offshore or land-based projects are introduced. With samples from these projects and laboratory tests, statistical analysis is made on the increment law of the strength of cement-soil mixture with different amount of cement, and strengths under different working conditions are compared. It is found that the amount of cement in the cement-soil mixture is closely related to the unconfined compressive strength of the mixture. At the age of 90 d,the unconfined compressive strength of the cement-soil mixture increased by 0.054 Mpa-0.124 Mpa with each cement increasing 10 kg/m3 in the cement-soil mixture, averagely increased by 0.085 Mpa, while that at the age of 120 d increased by 11% in comparison.The quality of the cement-soil mixture should be comprehensively evaluated in accordance with the trimmed average of strength, coefficient of variation and rock quality designation (RQD) indicators of sampling ratio.

  11. Cement treated recycled crushed concrete and masonry aggregates for pavements

    NARCIS (Netherlands)

    Xuan, D.X.

    2012-01-01

    This research is focusing on the characterization of the mechanical and deformation properties of cement treated mixtures made of recycled concrete and masonry aggregates (CTMiGr) in relation to their mixture variables. An extensive laboratory investigation was carried out, in which the mechanical p

  12. Durability of compressed soil-cement bricks

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    Acosta Valle, A.

    2001-06-01

    Full Text Available This papers shows the evaluation process of the durability of compressed soil-cement bricks. A great number of tests were made to determine the behavior of bricks when they are compression loaded and under the influence of moisture. Two different types of soils were used to produce the bricks, a lime-clay soil and a sand one. The sand soil is very resistant. The other one has a limited use. An experimental design was used to test the bricks. It is a rotational and quadratic method with a hexagonal figure which contains replicas at the central point. This method ensures the reliability of test results. Otherwise, it would reduce the amount of specimens necessary for the tests. The optimun moisture content is obtained by using a press machine. It is more rational than the standard Proctor compactation test, because it applies the same type and amount of energy used to produce the bricks. The obtained results show the behavior differences between the two compressed soil-cement bricks subjected to the compression test, water absorption and wetting and drying tests. The durability tests results are very important in the possible use of the bricks produced.

    En el trabajo se evalúa la durabilidad de elementos aglomerados de suelo estabilizado. Se realiza un amplio número de ensayos encaminados a determinar el comportamiento frente a la acción de las cargas y la humedad de dos suelos con características diferentes: uno limo-arcilloso y el otro arenoso. Este último presenta resultados muy favorables en ambas direcciones. El otro, con un posible uso más limitado. Se emplea un método de diseño experimental del tipo rotacional cuadrático en hexágono, con réplicas en el punto central, el que garantiza la confiabilidad de los resultados de los ensayos, a la vez que disminuye la cantidad de especímenes a ensayar. Se determina la humedad óptima a utilizar en las diferentes dosificaciones empleando la máquina compactadora, que resulta m

  13. Hydraulic Conductivity of Residual Soil-Cement Mix

    Science.gov (United States)

    Govindasamy, P.; Taha, M. R.

    2016-07-01

    In Malaysia, although there are several researches on engineering properties of residual soils, however study on the hydraulic conductivity properties of metasedimentary residual soils is still lacking. Construction of containment walls like slurry wall techniques can be achieved with hydraulic conductivity of approximately 5 x 10-7cm/sec. The objectives of the study were to determine the physical properties of metasedimentary residual soils and to determine the influence of 1%, 3%, 5% and 10% of cement on hydraulic conductivity parameters. The coefficient of hydraulic conductivity of the soil naturally and soil-cement mixtures were determined by using the falling head test. According to the test, the hydraulic conductivity of the original soil was 4.16 x 10-8 m/s. The value decreases to 3.89 x 10-8 m/s, 2.78 x 10-8 m/s then 6.83 x 10-9 m/s with the addition of 1%, 3% and 5% of cement additives, respectively. During the hydration process, cement hydrates is formed followed by the increase in pH value and Ca(OH)2 which will alter the modification of pores size and distribution. When the quantity of cement increases, the pores size decrease. But, the addition of 10% cement gives an increased hydraulic conductivity value to 2.78 x 10-8 m/s. With 10%, the pore size increase might due to flocculation and agglomeration reaction. The generated hydraulic conductivity values will indirectly become a guide in the preliminary soil cement stabilization to modify the properties of the soil to become more like the properties of a soft rock.1. Introduction

  14. Cement treated recycled crushed concrete and masonry aggregates for pavements

    OpenAIRE

    Xuan, D.X.

    2012-01-01

    This research is focusing on the characterization of the mechanical and deformation properties of cement treated mixtures made of recycled concrete and masonry aggregates (CTMiGr) in relation to their mixture variables. An extensive laboratory investigation was carried out, in which the mechanical properties of CTMiGr and the deformation characteristics relevant to shrinkage crack susceptibility were evaluated. The main aim of this research is to develop models which allow the structural prop...

  15. Mechanism of cement-stabilized soil polluted by magnesium sulfate

    Institute of Scientific and Technical Information of China (English)

    HAN Peng-ju; WANG Shuai; Frank Y. Chen; BAI Xiao-hong

    2015-01-01

    In order to simulate and study the mechanism of cement stabilized soils polluted by different contents of magnesium sulfate (MS), a series of tests were conducted on the cemented soil samples, including unconfined compression strength (UCS) tests of blocks, X-ray diffraction (XRD) phase analysis of powder samples, microstructure by scanning electronic microscopy (SEM), element composition by energy dispersive spectrometry (EDS), and pore distribution analysis by Image Processed Plus 6.0 (IPP 6.0) software. The UCS test results show that UCS of cemented soils reaches the peak value when the MS content is 4.5 g/kg. While, the UCS for Sample MS4 having the MS content of 18.0 g/kg is the lowest among all tested samples. Based on the EDS analysis results, Sample MS4 has the greater contents for the three elements, oxygen (O), magnesium (Mg) and sulfur (S), than Sample MS1. From the XRD phase analysis, C-A-S-H (3CaO·Al2O3·3CaSO4·32H2O and 3CaO·Al2O3·CaSO4·18H2O), M-A-H (MgO·Al2O3·H2O), M-S-H (MgO·SiO2·H2O), Mg(OH)2 and CaSO4phase diffraction peaks are obviously intense due to the chemical action associated with the MS. The pore distribution analysis shows that the hydrated products change the distribution of cemented soil pores and the pores with average diameter (AD) of 2-50μm play a key role in terms of the whole structure of cemented soil. The microscopic structure of the cemented soil with MS exhibits the intertwined and embedded characteristics between the cement and granular soils from the SEM images of cemented soils. The microstructure analysis shows that the magnesium sulfate acts as the additive, which is beneficial to the soil strength when the MS content is low (i.e., Sample MS2). However, higher MS amount involving a chemical action makes samples crystallize and expand, which is adverse to the UCS of cemented soils (i.e., Sample MS4).

  16. Soil-cement piles by drilling-mixing method

    OpenAIRE

    ZOTSENKO N.; VYNNYKOV YU.; ZOTSENKO V.

    2015-01-01

    Development of the drilling-mixing technology lead to the appearance of the soil-cement piles. It has all advantages of the drilling piles, but it eliminate the problem of the well walls stability. Drilling-mixing technology consist in, that machine with drilling-mixing head loosen soil; impregnated it by laitance; and mixed. Piles are perform from the excavation bottom until design depth. The movable soil-cement mixture feels wells during all the process. Pile has cylindrical form with set s...

  17. Stabilization/solidification of selenium-impacted soils using Portland cement and cement kiln dust.

    Science.gov (United States)

    Moon, Deok Hyun; Grubb, Dennis G; Reilly, Trevor L

    2009-09-15

    Stabilization/solidification (S/S) processes were utilized to immobilize selenium (Se) as selenite (SeO(3)(2-)) and selenate (SeO(4)(2-)). Artificially contaminated soils were prepared by individually spiking kaolinite, montmorillonite and dredged material (DM; an organic silt) with 1000 mg/kg of each selenium compound. After mellowing for 7 days, the Se-impacted soils were each stabilized with 5, 10 and 15% Type I/II Portland cement (P) and cement kiln dust (C) and then were cured for 7 and 28 days. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effectiveness of the S/S treatments. At 28 days curing, P doses of 10 and 15% produced five out of six TCLP-Se(IV) concentrations below 10mg/L, whereas only the 15% C in DM had a TCLP-Se(IV) concentration pozzolan doses up to 10 times less than the treatments that established the BDAT. Neither pozzolan was capable of reducing the TCLP-Se(VI) concentrations below 25mg/L. Se-soil-cement slurries aged for 30 days enabled the identification of Se precipitates by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX). XRD and SEM-EDX analyses of the Se(IV)- and Se(VI)-soil-cement slurries revealed that the key selenium bearing phases for all three soil-cement slurries were calcium selenite hydrate (CaSeO(3).H(2)O) and selenate substituted ettringite (Ca(6)Al(2)(SeO(4))(3)(OH)(12).26H(2)O), respectively.

  18. Stabilization/solidification of selenium-impacted soils using Portland cement and cement kiln dust

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Deok Hyun, E-mail: dmoon10@hotmail.com [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Department of Environmental Engineering, Chosun University, Gwangju 501-759 (Korea, Republic of); Grubb, Dennis G. [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Schnabel Engineering, LLC, 510 East Gay Street, West Chester, PA 19380 (United States); Reilly, Trevor L. [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)

    2009-09-15

    Stabilization/solidification (S/S) processes were utilized to immobilize selenium (Se) as selenite (SeO{sub 3}{sup 2-}) and selenate (SeO{sub 4}{sup 2-}). Artificially contaminated soils were prepared by individually spiking kaolinite, montmorillonite and dredged material (DM; an organic silt) with 1000 mg/kg of each selenium compound. After mellowing for 7 days, the Se-impacted soils were each stabilized with 5, 10 and 15% Type I/II Portland cement (P) and cement kiln dust (C) and then were cured for 7 and 28 days. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effectiveness of the S/S treatments. At 28 days curing, P doses of 10 and 15% produced five out of six TCLP-Se(IV) concentrations below 10 mg/L, whereas only the 15% C in DM had a TCLP-Se(IV) concentration <10 mg/L. Several treatments satisfied the USEPA TCLP best demonstrated available technology (BDAT) limits (5.7 mg/L) for selenium at pozzolan doses up to 10 times less than the treatments that established the BDAT. Neither pozzolan was capable of reducing the TCLP-Se(VI) concentrations below 25 mg/L. Se-soil-cement slurries aged for 30 days enabled the identification of Se precipitates by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX). XRD and SEM-EDX analyses of the Se(IV)- and Se(VI)-soil-cement slurries revealed that the key selenium bearing phases for all three soil-cement slurries were calcium selenite hydrate (CaSeO{sub 3}.H{sub 2}O) and selenate substituted ettringite (Ca{sub 6}Al{sub 2}(SeO{sub 4}){sub 3}(OH){sub 12}.26H{sub 2}O), respectively.

  19. Peach leaf responses to soil and cement dust pollution.

    Science.gov (United States)

    Maletsika, Persefoni A; Nanos, George D; Stavroulakis, George G

    2015-10-01

    Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content.

  20. A Model of Thermal Conductivity for Planetary Soils. 2; Theory for Cemented Soils

    Science.gov (United States)

    Piqueux, S.; Christensen, P. R.

    2009-01-01

    A numerical model of heat conduction through particulate media made of spherical grains cemented by various bonding agents is presented. The pore-filling gas conductivity, volume fraction, and thermal conductivity of the cementing phase are tunable parameters. Cement fractions factor 3-8) is observed for bond fractions of 0.01 to 1% in volume. In the 1 to 15% bond fraction domain, the conductivity increases continuously but less intensely (25-100% conductivity increase compared to a 1% bond system). Beyond 15% of cements, the conductivity increases vigorously and the bulk conductivity rapidly approaches that of bedrock. The composition of the cements (i.e. conductivity) has little influence on the bulk thermal inertia of the soil, especially if the volume of bond cemented soils and quantify the amount of cementing phase, but the mineralogical nature of the bonds and the typical grain size are unlikely to be determined from orbit. On Mars, a widespread surface unit characterized by a medium albedo (0.19-0.26) and medium/high thermal inertia (200-600 J s(0.5)/sq m/K) has long been hypothesized to be associated with a duricrust. The fraction of cement required to fit the thermal data is less than approx.1-5% by volume. This small amount of material is consistent with orbital observations, confirming that soil cementation is an important factor controlling the thermal inertia of the Martian surface

  1. Fracture analysis of cement treated demolition waste using a lattice model

    NARCIS (Netherlands)

    Xuan, D.; Schlangen, H.E.J.G.; Molenaar, A.A.A.; Houben, L.J.M.

    2013-01-01

    Fracture properties of cement treated demolition waste were investigated using a lattice model. In practice the investigated material is applied as a cement treated road base/subbase course. The granular aggregates used in this material were crushed recycled concrete and masonry. This results in six

  2. Life Cycle Assessment on Cement Treated Recycling Base (CTRB Construction

    Directory of Open Access Journals (Sweden)

    Sudarno Sudarno

    2014-08-01

    Full Text Available LCA is one of the few environmental management techniques that are used to perform a risk assessment, environmental performance evaluation, environmental auditing, and environmental impact assessment and must be applied to the construction CTRB. The purpose of this study was to determine the amount of energy consumption is used and determine the amount of emissions (CO2 in the implementation of the Foundation Layer Top (base course with the former asphalt pavement aggregate blended cement / Recycling Cement Treated Base (CTRB. This study uses: (i Compilation and data inventory of relevant inputs and outputs of a product system; (ii Evaluating the potential environmental impacts associated with the data input and output; (iii Interpret the results of the inventory analysis and impact assessment in relation to the research objectives. The results showed that Energy consumption in the implementation of recycling pavement (CTRB is 225.46 MJ / km of roads and the resulting GHG emissions 17,43Ton CO2 / km of roads. Previous researchers to calculate the energy consumption of road works on the implementation of conventional (hotmix is 383.46 MJ / km of roads and the resulting GHG emissions 28.24 Ton CO2 / km of roads. If the calculated difference between a job and Hotmix CTRB and then a comparison is made CTRB energy consumption is 158 MJ / km of road, this happens 70.07% savings and GHG emissions resulting difference is 10.81 tons of CO2 / km of road, resulting in a decrease in 62,02%.

  3. A constitutive model for unsaturated cemented soils under cyclic loading

    CERN Document Server

    Yang, C; Pereira, Jean-Michel; Huang, M S

    2008-01-01

    On the basis of plastic bounding surface model, the damage theory for structured soils and unsaturated soil mechanics, an elastoplastic model for unsaturated loessic soils under cyclic loading has been elaborated. Firstly, the description of bond degradation in a damage framework is given, linking the damage of soil's structure to the accumulated strain. The Barcelona Basic Model (BBM) was considered for the suction effects. The elastoplastic model is then integrated into a bounding surface plasticity framework in order to model strain accumulation along cyclic loading, even under small stress levels. The validation of the proposed model is conducted by comparing its predictions with the experimental results from multi-level cyclic triaxial tests performed on a natural loess sampled beside the Northern French railway for high speed train and about 140 km far from Paris. The comparisons show the capabilities of the model to describe the behaviour of unsaturated cemented soils under cyclic loading.

  4. Triaxial shear behavior of a cement-treated sand–gravel mixture

    Directory of Open Access Journals (Sweden)

    Younes Amini

    2014-10-01

    Full Text Available A number of parameters, e.g. cement content, cement type, relative density, and grain size distribution, can influence the mechanical behaviors of cemented soils. In the present study, a series of conventional triaxial compression tests were conducted on a cemented poorly graded sand–gravel mixture containing 30% gravel and 70% sand in both consolidated drained and undrained conditions. Portland cement used as the cementing agent was added to the soil at 0%, 1%, 2%, and 3% (dry weight of sand–gravel mixture. Samples were prepared at 70% relative density and tested at confining pressures of 50 kPa, 100 kPa, and 150 kPa. Comparison of the results with other studies on well graded gravely sands indicated more dilation or negative pore pressure in poorly graded samples. Undrained failure envelopes determined using zero Skempton's pore pressure coefficient (A¯=0 criterion were consistent with the drained ones. Energy absorption potential was higher in drained condition than undrained condition, suggesting that more energy was required to induce deformation in cemented soil under drained state. Energy absorption increased with increase in cement content under both drained and undrained conditions.

  5. Stabilization of Black Cotton Soil With Sand and Cement as a Subgrade for Pavement

    OpenAIRE

    Mrs. Neetu B. Ramteke *1 ,; Prof. Anilkumar Saxena 2 ,; , Prof. T. R. Arora 3

    2014-01-01

    Expansive soil (Black cotton soil) is very weak and does not have enough stability for any type of construction work. In pavement, subgrade layer is the bottommost layer underlying the base course or surface course. To make the subgrade soil stable, by improving its engineering properties is very essential. In the present work, stabilization of subgrade soil by using sand and cement (varying percentage of sand and constant percentage of cement by weight of soil) is used to enh...

  6. A mild alkali treated jute fibre controlling the hydration behaviour of greener cement paste

    Science.gov (United States)

    Jo, Byung-Wan; Chakraborty, Sumit

    2015-01-01

    To reduce the antagonistic effect of jute fibre on the setting and hydration of jute reinforced cement, modified jute fibre reinforcement would be a unique approach. The present investigation deals with the effectiveness of mild alkali treated (0.5%) jute fibre on the setting and hydration behaviour of cement. Setting time measurement, hydration test and analytical characterizations of the hardened samples (viz., FTIR, XRD, DSC, TGA, and free lime estimation) were used to evaluate the effect of alkali treated jute fibre. From the hydration test, the time (t) required to reach maximum temperature for the hydration of control cement sample is estimated to be 860 min, whilst the time (t) is measured to be 1040 min for the hydration of a raw jute reinforced cement sample. However, the time (t) is estimated to be 1020 min for the hydration of an alkali treated jute reinforced cement sample. Additionally, from the analytical characterizations, it is determined that fibre-cement compatibility is increased and hydration delaying effect is minimized by using alkali treated jute fibre as fibre reinforcement. Based on the analyses, a model has been proposed to explain the setting and hydration behaviour of alkali treated jute fibre reinforced cement composite. PMID:25592665

  7. Reduction of soil pollution by usingwaste of the limestone in the cement industry

    Science.gov (United States)

    Muñoz, M. Cecilia Soto; Robles Castillo, Marcelo; Blanco Fernandez, David; Diaz Gonzalez, Marcos; Naranjo Lamilla, Pedro; Moore Undurraga, Fernando; Pardo Fabregat, Francisco; Vidal, Manuel Miguel Jordan; Bech, Jaume; Roca, Nuria

    2016-04-01

    In the cement manufacturing process (wet) a residue is generated in the flotation process. This builds up causing contamination of soil, groundwater and agricultural land unusable type. In this study to reduce soil and water pollution 10% of the dose of cement was replaced by waste of origin limestone. Concretes were produced with 3 doses of cement and mechanical strengths of each type of concrete to 7, 28 and 90 days were determined. the results indicate that the characteristics of calcareous residue can replace up to 10% of the dose of cement without significant decreases in strength occurs. It is noted that use of the residue reduces the initial resistance, so that the dose of cement should not be less than 200 kg of cement per m3. The results allow recommends the use of limestone waste since it has been observed decrease in soil and water contamination without prejudice construction material Keywords: Soil contamination; Limestone residue; Adding concrete

  8. Influence of the cement production aerotechnogenic emissions on the filtration properties of the soil

    OpenAIRE

    O. Iziumova

    2015-01-01

    The results of investigations over the filtration properties of ash-laden black soil under the cement production pollution emissions have been given. The general tendencies in formation of the quantitative characteristics of the soil filtration properties estimated by filtration coefficient under cement dust pollution have been clarified.

  9. Analysis of the Damping Behavior and Microstructure of Cement Matrix with Silane-treated Silica Fume

    Institute of Scientific and Technical Information of China (English)

    OU Jinping; LIU Tiejun; LI Jiahe

    2006-01-01

    The surface treatment of silica fume with silane coupling agent prior to incorporation in a cement mortar resulted in composites exhibiting increases in loss tangent by 5%-200% and storage modulus by 10%-20%, relative to the value obtained by using as-received silica fume. The scanning electron microscopy (SEM) images indicate that there is a morphological difference in the cement paste with treated and as-received silica fume. The X-ray diffraction (XRD), infrared (IR) spectrum analyses and mercury intrusion porosimetry (MIP) have provided evidence to understand the reaction mechanism between treated silica fume and the hydrate product of cement. This has led to the establishment of an initial microscopic model describing the damping behavior of cement matrix.

  10. The Properties of Road Base Course Materials of Granular Soils Stabilized by AGS Granular Soil Stabilizing Cement

    Institute of Scientific and Technical Information of China (English)

    SHEN Wei-guo; ZHOU Ming-kai; ZHAO Qing-lin; WU Shao-peng

    2003-01-01

    The properties of road base course materials of granular soils stabilized by AGS granular soil stabilizing cement[1]were studied.The AGS cement has an expansibility to a certain degree,so the dry shrinkage of AGS cement paste and AGS stabilized granular is much lower than that of Portland slag cement.AGS has a good suitability to granular soils.Granular soils stabilized by AGS have a much higher strength than that of soils stabilized by P S cement.The same strength can be reached with 20% reduction of cement dosage for AGS cement.And their elastic and resilient modulus are similar,but the former has a much higher tensile splitting strength,so the AGS stabilized granular has a much better anti-cracking performance than that of the P S stabilized granular.The reduced value of the strength and the density with the retard time for the granular soils stabilized by AGS is lower than that for P S cement.

  11. Swelling Properties of Expansive Soils Treated with Chemicals and Flyash

    Directory of Open Access Journals (Sweden)

    G Radhakrishnan

    2016-08-01

    Full Text Available Expansive soil shows recurrent volume changes with the changes moisture content, causing serious problems to the civil engineering structures such as road pavements resting on them. Several attempts are being made all over the world to control the swell shrink behavior of expansive soils. Flexible Pavements constructed on these soil shows signs of damage continuously during the service life of the pavement causes an increase in the maintenance costs. Numerous methods are available in the stabilization of expansive subgrade soil. Many researchers have made an attempt with the chemical stabilization technique, it has gained prominence due to its easy applicability and adaptability. Flyash is freely available waste product which has little cementing property can be used for altering the characteristics of expansive soil. The main objective of this work is to study the swelling properties of the expansive subgrade soil treated with chemicals like Magnesium Chloride (MgCl2, Aluminum Chloride (AlCl3 and also by adding flyash in varying percentages. The swelling properties of the collected expansive soil samples were determined based on the parameters like Free Swell Index, Swell Potential and Swell Pressure. The results obtained from the experimental study indicate that the measured Free Swell, Swell Potential and Swelling Pressure are reduced substantially with the increasing percent of chemicals and flyash and remain stable after reaching certain concentration. This paper discusses the results of the testing.

  12. Mechanical and leaching behaviour of slag-cement and lime-activated slag stabilised/solidified contaminated soil.

    Science.gov (United States)

    Kogbara, Reginald B; Al-Tabbaa, Abir

    2011-05-01

    Stabilisation/solidification (S/S) is an effective technique for reducing the leachability of contaminants in soils. Very few studies have investigated the use of ground granulated blast furnace slag (GGBS) for S/S treatment of contaminated soils, although it has been shown to be effective in ground improvement. This study sought to investigate the potential of GGBS activated by cement and lime for S/S treatment of a mixed contaminated soil. A sandy soil spiked with 3000mg/kg each of a cocktail of heavy metals (Cd, Ni, Zn, Cu and Pb) and 10,000mg/kg of diesel was treated with binder blends of one part hydrated lime to four parts GGBS (lime-slag), and one part cement to nine parts GGBS (slag-cement). Three binder dosages, 5, 10 and 20% (m/m) were used and contaminated soil-cement samples were compacted to their optimum water contents. The effectiveness of the treatment was assessed using unconfined compressive strength (UCS), permeability and acid neutralisation capacity (ANC) tests with determination of contaminant leachability at the different acid additions. UCS values of up to 800kPa were recorded at 28days. The lowest coefficient of permeability recorded was 5×10(-9)m/s. With up to 20% binder dosage, the leachability of the contaminants was reduced to meet relevant environmental quality standards and landfill waste acceptance criteria. The pH-dependent leachability of the metals decreased over time. The results show that GGBS activated by cement and lime would be effective in reducing the leachability of contaminants in contaminated soils. PMID:21420148

  13. Reuse of grits waste for the production of soil--cement bricks.

    Science.gov (United States)

    Siqueira, F B; Holanda, J N F

    2013-12-15

    This investigation focuses on the reuse of grits waste as a raw material for replacing Portland cement by up to 30 wt.% in soil-cement bricks. The grits waste was obtained from a cellulose factory located in south-eastern Brazil. We initially characterized the waste sample with respect to its chemical composition, X-ray diffraction, fineness index, morphology, pozzolanic activity, and pollution potential. Soil-cement bricks were then prepared using the waste material and were tested to determine their technological properties (e.g., water absorption, apparent density, volumetric shrinkage, and compressive strength). Microstructural evolution was accompanied by confocal microscopy. It was found that the grits waste is mainly composed of calcite (CaCO3) particles. Our results indicate that grits waste can be used economically, safely, and sustainably at weight percentages of up to 20% to partially replace Portland cement in soil-cement bricks. PMID:24140481

  14. Laboratorial study of soil-cement mixtures for aplication in Jet Grouting

    OpenAIRE

    Valente, Tiago; Correia, A. Gomes; Vale, José Machado do; Barata, J.; Cebola, Duílio; Coelho, Sandra

    2008-01-01

    In this paper is presented a laboratorial study of different formulations of soil-cement mixtures to support field trial of Jet Grouting columns. Laboratorial tests results of mechanical and physical characterization are discussed, specifically the uniaxial compressive strength (450 specimens), initial, maximum, secant ant tangent to 50% stiffness moduli (18 specimens) and density of the soil-cement mixtures (468 specimens). The stiffness moduli were obtained using the technique of measuremen...

  15. [Peculiarities of structure-function organization of microbial groups of soil contaminated by cement dust].

    Science.gov (United States)

    Stefurak, V P

    2001-01-01

    Long-term contamination of the forest soil by the cement dust leads to disturbances of stability of natural microbial groups, changes their quantitative and qualitative composition, results in substitution of some microbial associations by other ones. The intensive contamination of the soil by the effluents of cement integrated works, inhibits the intensity of nitrogen fixation processes and decay of the forest litter, development of micromycetes, results in the decrease of the length of mycelium and its biomass. PMID:11692672

  16. Laboratory Test on Long-Term Deterioration of Cement Soil in Seawater Environment

    Institute of Scientific and Technical Information of China (English)

    杨俊杰; 闫楠; 刘强; 张玥宸

    2016-01-01

    Laboratory tests were conducted to study the effects of curing time, cement ratio and seawater pressure on cement soil deterioration formed at simulative marine soft clay sites. Deterioration depth was determined on the basis of characteristics of penetration resistance and penetration depth curves, and the deterioration depth of cement soil with the cement ratio of 7%, reached 31.8 mm after 720 d. Results of research indicated that deterioration ex-tended quickly under seawater environment and the deterioration depth increased with the prolonging curing time. In addition, the water pressure could speed up deterioration. With the increase of cement content, the strength of cement soil increased obviously. At the same time, the deterioration depth decreased significantly. The concentra-tion of calcium ion in the cement stabilized soil increased with the increase of depth, while that of magnesium ion gradually decreased. The variations were consistent with energy dispersive spectrometer(EDS)analysis results, and the calcium concentration with depth was in a good consistency with strength distribution at long term. The results showed that the deterioration became more serious with the curing time, and it was related to calcium leaching.

  17. Analysis on Settlement Deformation of Soft Soil Foundation Treated by Cement Mortar Pile in High-Speed Railway%水泥砂浆桩处理某高速铁路软基沉降变形分析

    Institute of Scientific and Technical Information of China (English)

    金海元; 周宏元; 陈尚勇

    2012-01-01

    高速铁路对路基工后沉降提出了严格的要求,某高速铁路路基段存在大范围软土地基,采用水泥砂浆桩进行地基加固处理。通过对地基处理后一年多的路基沉降变形观测分析及预测表明:各观测点的沉降量-时间曲线均已经收敛,路堤荷载作用下路基面沉降已经稳定,沉降板预测最大工后沉降ΔS’为4.8mm,路基面观测桩双曲线法预测路基面最大残余沉降为2.3mm,沉降完成比例St/S∞最小为92.4%,均满足高速铁路沉降控制标准。因此,水泥砂浆桩处理高速铁路软土地基是可行的,可以在较短时间内满足工后沉降的要求。%High-speed railway puts forward strict demands on post construction settlement. There is a wide range of soft ground at one high-speed railway embankment, which is strengthened by cement mortar pile. Based on a- nalysis and prediction of settlement after one and a half years monitoring, we have found that settlement-time curves of every observation points are convergent and settlement of embankment surface under embankment load is stable. The predicted maximum post construction settlement (AS') of settlement plate is 4.8mm and the maxi- mum residual settlement of observation pile predicted by hyperbolic method is 2.3ram, the minimum completion percentage ( S/S~ ) of settlement is 92.4%, all of which can meet the settlement control standard of high-speed railway. So it is feasible to reinforce the soft foundation of high-speed railway with cement mortar pile because it can meet the requirements of the settlement in a relatively short period of time.

  18. Effect of Heavy Metal Present in Cement Dust on Soil and Plants of Nokha (Bikaner

    Directory of Open Access Journals (Sweden)

    Dr.(Mrs.Suruchi Gupta

    2013-08-01

    Full Text Available In Nokha(Bikaner cement industries emittes cement dust in nearby farmers fields. In these industries cement dust emitted contains traces of hexavalent chromium and lead well above permissible limit in area under investigation. However, cadmium and nickel were found below limits prescribed. To analyse heavy metals viz, Cr+6, lead, Cadmium and nickel one hundred and twenty samples were collected from four directions on surface and 20 cm depth, and analyzed on atomic absorption spectrophotometer. From the above study it is clear that in case of Sarvottam cement works only lead content was higher in all directions and depths than other two plants. At tiger and Nokha cement works contamination of lead was more over limited in the first 1 km except in east direction. Mobility of lead was relatively more on top soil than 20cm depth. Hexavalent chromium content in south western direction was more for Nokha cement. Whereas, it was more in east direction in case of tiger cement. This indicated influence of prevailing direction of wind on distribution of heavy metals present in cement dust.Heavy metal toxicity results in reduction in plant height, burning of leaf margins and tip, slow leaf growth and over all wilting of Prosopis cineraria, Pearlmillet and clusterbean plants, when this metal deposits in Human body results in genetic disorders. Electrostatic precipitator can be installed to reduce the cement dust emission.

  19. The Effect of Polymer-Cement Stabilization on the Unconfined Compressive Strength of Liquefiable Soils

    OpenAIRE

    Ali Ateş

    2013-01-01

    Soil stabilization has been widely used as an alternative to substitute the lack of suitable material on site. The use of nontraditional chemical stabilizers in soil improvement is growing daily. In this study a laboratory experiment was conducted to evaluate the effects of waterborne polymer on unconfined compression strength and to study the effect of cement grout on pre-venting of liquefiable sandy soils. The laboratory tests were performed including grain size of sandy soil, unit weight, ...

  20. Stabilization treatment of soft subgrade soil by sewage sludge ash and cement.

    Science.gov (United States)

    Chen, Li; Lin, Deng-Fong

    2009-02-15

    In this study, incinerated sewage sludge ash (ISSA) is mixed with cement in a fixed ratio of 4:1 for use as a stabilizer to improve the strength of soft, cohesive, subgrade soil. Five different ratios (in wt%: 0%, 2%, 4%, 8%, and 16%) of ISSA/cement admixture are mixed with cohesive soil to make soil samples. In order to understand the influences of admixtures on the soil properties, tests of the pH value, Atterberg limits, compaction, California bearing ratio (CBR), unconfined compressive strength, and triaxial compression were performed on those samples. The study shows that the unconfined compressive strength of specimens with the ISSA/cement addition was improved to approximately 3-7 times better than that of the untreated soil; furthermore, the swelling behavior was also effectively reduced as much as 10-60% for those samples. In some samples, the ISSA/cement additive improved the CBR values by up to 30 times that of untreated soil. This suggests that ISSA/cement has many potential applications in the field of geotechnical engineering. PMID:18579294

  1. Stabilisation of clayey soils with high calcium fly ash and cement

    Energy Technology Data Exchange (ETDEWEB)

    S. Kolias; V. Kasselouri-Rigopoulou; A. Karahalios [National Technical University of Athens, Athens (Greece)

    2005-02-01

    The effectiveness of using high calcium fly ash and cement in stabilising fine-grained clayey soils (CL,CH) was investigated in the laboratory. Strength tests in uniaxial compression, in indirect (splitting) tension and flexure were carried out on samples to which various percentages of fly ash and cement had been added. Modulus of elasticity was determined at 90 days with different types of load application and 90-day soaked CBR values are also reported. Pavement structures incorporating subgrades improved by in situ stabilisation with fly ash and cement were analyzed for construction traffic and for operating traffic. These pavements are compared with conventional flexible pavements without improved subgrades and the results clearly show the technical benefits of stabilising clayey soils with fly ash and cement. In addition TG-SDTA and XRD tests were carried out on certain samples in order to study the hydraulic compounds, which were formed.

  2. Characterization of waste products prepared from radioactive contaminated clayey soil cemented according to the GEODUR process

    International Nuclear Information System (INIS)

    Radioactive contaminated soil may arise due to accidents of various types or may be detected during decommisioning of nuclear installations. Ordinary surface soil cannot normally be conditioned using conventional cementation processes since the content of humic materials retards or prevents the solidification. An additive available from the Danish firm Geodur A/S makes it possible to circumvent this difficulty and to produce a monolithic, nondusting waste type using rather small amounts of cement. The report describes work on characterization of such a cemented waste product prepared on basis of clayey top soil from the Risoe area. The claimed advantages of the process was verified, and data for the compression strength (low), hydraulic conductivity (satisfactory) and other pore structure-related properties are given for the obtained products. Unfortunately the behaviour of cesium and strontium, representing two of the most relevant radionuclides, was not too promising. The retention of cesium is satisfactory, but less good than for the untreated soil. Greatly improved cesium retention after drying of the materials was noticed. Good retention of strontium is only obtained after reaction of the material with carbon dioxide from the atmosphere. The behaviour of the two isotopes in other types of cemented waste is somewhat similar, but the decrease in retention compared with untreated soil makes the process less interesting as a possibility for remedial actions after accidents, etc. Some further studies of the cemented soil waste are beeing made within the frame of the Nordic Nuclear Safety Studies. Elements forming low solublity components in the high pH environment in the cemented soil will probably be retained quite efficiently. This was demonstrated in case of Zn. (author) 11 tabs., 22 ills., 8 refs

  3. Compound soil-tyre chips modified by cement as a road construction material

    Directory of Open Access Journals (Sweden)

    Panu Promputthangkoon

    2013-10-01

    Full Text Available This research attempts to overcome the two problems of low-quality soil and a growing number of discarded tyres bymixing low-CBR soil with recycled tyre chips. The compound soil-tyre chips was then stabilised by Portland cement with theaim of using them as a new material in road construction in order to reduce the occurrence of shrinkage cracks. To achievethe purposes of this research three standard geotechnical testing programmes were employed: (1 modified compaction tests,(2 California Bearing Ratio tests (CBR, and (3 unconfined compression tests. The modified compaction test results provedthat for the mixtures having very low tyre chips and cement content, the behaviour is very complex. It was also observed thatthe greater the percentage of rubber added the lower the global density. However, this is predictable as the specific gravityof the rubber is much lower than that of the soil. For the relationship between the optimum moisture content (OMC and thecement content, it was observed that there is no clear pattern.For the specimens having no cement added, the CBR for unsoaked specimens was observed to be greater than that forsoaked specimens. However, when the cement was introduced the CBR test showed that the resistance to penetration for thesoaked specimens was significantly greater, indicating the effects of cement added on the strength. In addition, it was foundthat the CBR values for both soaked and unsoaked specimens gradually increased with the increase of cement content.Lastly, the unconfined compressive strength progressively increased with the increased percentage of cement.

  4. Experimental study of composite soil cement%水泥复合土试验研究

    Institute of Scientific and Technical Information of China (English)

    赫文秀

    2014-01-01

    本试验以水泥和粘土为主要原料,将粉煤灰和玻璃纤维掺入到水泥土中,通过室内三轴试验,得到水泥复合土的应力应变曲线。通过对实测的应力应变曲线分析可知:水泥复合土的应力应变曲线呈软化型,存在明显的应力峰值点,可将其分为:弹性变形区、塑性变形发展区、应力衰减区、残余强度区四个发展阶段。与此同时,通过对水泥复合土试件破坏过程的分析发现:水泥复合土的破坏形式为脆性剪切破坏和胀裂破坏。%In this experiment,the main raw material of cement and clay,fly ash cement and glass fibers incor-porated into the soil,through laboratory triaxial tests,the stress-strain curve obtained cement composite soil. Through the measured stress-strain curve analysis:Stress-strain curves showed a softening of cement compos-ite soil type,there is an obvious peak stress points,which can be divided into:elastic deformation zones,the development zone of plastic deformation ,stress relaxation area ,residual strength zone four stages of develop-ment.At the same time ,through the cement composite soil specimen failure process analysis found:cement composite soil damage in the form of brittle shear failure and bursting destruction .

  5. Cement grouting during installation of ground anchors in non-cohesive soils

    OpenAIRE

    Domes, Xenia A. L.

    2015-01-01

    Pressure grouting during installation of grouted ground anchors is known to increase anchor capacity in non-cohesive soils, but little information is available on correlations between applied grouting pressures, duration of grouting, ground conditions and increase of anchor pull-out capacity. The presented PhD study is concerned with processes taking place during installation of grouted ground anchors in non-cohesive soils, where filtration of the cement grout is assumed. It...

  6. Mechanical Behaviour of Composite Bioactive Bone Cements Consisting of Two Different Types of Surface Treated Hydroxyapatite as Filler

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Bioactive bone cements based on a paste-paste system for orthopaedic applications were developed consisting of hydroxyapatite ( HA ) filler particles in a methacrylate matrix comprising urethane dimethacrylate(UDMA) and triethylene glycol dimethacrylate ( TEGDMA ). To improve the interface between inorganic filler and orgaric matrix the HA particles were subjected to two different surface treatment methods, using polyacrylic acid ( PAA ) and γ- methacryloxy propyl trimethoxy silane (γMPS). The aim of the present study was to determine the influence of surface treatment and the inclusion of multifunctional methacrylates on the mechanical properties,namely 3-point flexural strength (FS) and fracture toughness of the cements and the effect of ageing in simulated body fluid. Comparing the mechanical properties of the two cements, the γMPS-HA cement showed that the fracture toughness of the experimental bone cements were significantly greater (p< 0.001) compared to that of the PMMA cement, whereas PAA-HA containing cement had strength values around 20% lower. Interestingly, PAA was found to be more effective in improving the interface as the PAA treated HA cement ( UTHAPPA ) maintained its strength on immersion in SBF , suggesting that PAA provided a coupling, which was less sensitive to moisture,a similar trend was also observed with the inclusion of the carboxyl containing multifunctional methacrylates.

  7. ALTERNATIVE FIELD METHODS TO TREAT MERCURY IN SOIL

    Energy Technology Data Exchange (ETDEWEB)

    Ernest F. Stine Jr; Steven T. Downey

    2002-08-14

    simulate expected ranges of mercury contamination and to increase the TCLP mercury values. IT/NFS investigated ambient temperature amalgamation/stabilization/fixation of mercury-contaminated soils to meet these objectives. Treatment ranged in size from a few ounces to 10 pounds. The treatability study philosophy was to develop working envelops of formulations where reasonable minimum and maximum amounts of each reagent that would successfully treat the contaminated soil were determined. The dosages investigated were based on ratios of stoichiometric reactions and applications of standard sets of formulations. The approach purposely identified formulations that failed short or longer cure-time performance criteria to define the limits of the envelope. Reagent envelops successfully met the project requirements one day after treatment and after greater than 30-day cures. The use of multiple levels of spikes allowed the establishment of reagent dosages that were successful across a broad range of mercury values, e.g., 50 to 6000 mg/kg mercury. The treatment products were damp to slightly wet material. Enough drying reagent, e.g., Portland cement or lime by-product, were added to some formulations to control the leachability of uranium and other hazardous metals and to ensure the product passed the paint filter test. Cost analyzes and conceptual designs for four alternatives for full-scale treatments were prepared. The alternatives included two in-situ treatments and two ex-situ treatments. The cost estimates were based on the results from the bench-scale study. All four alternatives treatment costs were well below the baseline costs.

  8. A constitutive model for unsaturated cemented soils under cyclic loading

    OpenAIRE

    Yang, C; Cui, Yu-Jun; Pereira, Jean-Michel; Huang, M.S.

    2008-01-01

    On the basis of plastic bounding surface model, the damage theory for structured soils and unsaturated soil mechanics, an elastoplastic model for unsaturated loessic soils under cyclic loading has been elaborated. Firstly, the description of bond degradation in a damage framework is given, linking the damage of soil's structure to the accumulated strain. The Barcelona Basic Model (BBM) was considered for the suction effects. The elastoplastic model is then integrated into a bounding surface p...

  9. Effects of Waste Glass (WG on the Strength Characteristics of Cement Stabilized Expansive Soil

    Directory of Open Access Journals (Sweden)

    I.A.Ikara

    2015-11-01

    Full Text Available The study investigates the suitability of using waste glass (WG as admixture to cement stabilized black cotton soil (BCS for roads, fills and embankment. The soil was classified as A-7-5 and CH according to the American Association of State Highway and Transport Officials (AASHTO and the Unified Soil Classification System (USCS Classifications. Chemical analysis revealed that WG is rich in main oxides such as Silicon Oxide (69.2, Aluminium Oxide (2.29, Iron Oxide (1.57, Calcium Oxide (15.1 and Sodium Oxide (8.75. The soil was stabilized with 0, 2, 4, 6 and 8% cement and 0, 5 10, 15 and 20% WG by weight of the dry soil. Laboratory tests were carried out using the Standard Proctor (SP compactive efforts, California Bearing Ratio (CBR, Unconfined Compressive Strength (UCS, and compaction characteristics tests to evaluate the effectiveness of WG on Ordinary Portland cement (OPC stabilized BCS. The results obtained showed a decrease in the plasticity index (PI, liquid limit (LL, plastic limit (PL and increase Maximum Dry Density (MDD with increase in WG content in all cement proportions used and as compared to the values obtained for the natural soil. The peak 7 days UCS values of 1152kN/m2 was obtained at 8% OPC and 20% WG. Similarly, highest CBR value of 53.8% was obtained at an optimum blend of 8% OPC/20%WG. The results indicate that there is a potential in the use of WG as admixture to strengthen Black cotton soils.

  10. Hybrid life cycle assessment comparison of colloidal silica and cement grouted soil barrier remediation technologies.

    Science.gov (United States)

    Gallagher, Patricia M; Spatari, Sabrina; Cucura, Jeffrey

    2013-04-15

    Site remediation involves balancing numerous costs and benefits but often neglects the environmental impacts over the entire project life cycle. Life cycle assessment (LCA) offers a framework for inclusion of global environmental "systems-level" decision metrics in combination with technological and cost analysis. We compare colloidal silica (CS) and cement grouted soil barrier remediation technologies for soils affected by low level radionuclides at a U.S. Superfund site using hybrid LCA methods. CS is a new, high performance grouting material installed using permeation grouting techniques. Cement, a more traditional grouting material, is typically installed using jet grouting techniques. Life cycle impacts were evaluated using the US EPA TRACI 2 model. Results show the highest life cycle environmental impacts for the CS barrier occur during materials production and transportation to the site. In general, the life cycle impacts for the cement barrier were dominated by materials production; however, in the extreme scenario the life cycle impacts were dominated by truck transportation of spoils to a distant, off-site radioactive waste facility. It is only in the extreme scenario tested in which soils are transported by truck (Option 2) that spoils waste transport dominates LCIA results. Life cycle environmental impacts for both grout barriers were most sensitive to resource input requirements for manufacturing volumes and transportation. Uncertainty associated with the efficacy of new technology such as CS over its required design life indicates that barrier replacement could increase its life cycle environmental impact above that of the cement barrier. PMID:23500422

  11. Determination of the Elemental Contents in Soils Around Diamond Cement Factory, Aflao

    Directory of Open Access Journals (Sweden)

    Hyacinthe Ahiamadjie

    2011-01-01

    Full Text Available This research is to assess the impact of the dusts particles given out by a cement factory on the physicochemical characteristics of the soil at the vicinity of the cement factory. Total concentration of five trace metals (Ca, Cu, Mn, Pb and V was measured in soils from within and surrounding areas of the Diamond Cement Factory, Aflao. Thirty four (34 surface soils (0-20 cm were collected during the month of November, 2009. The soil samples were air dried and sieved to appropriate sizes for analysis. The samples were subsequently pelletized and analyzed using XRF at the physics Department, Ghana Atomic Energy Commission. The results of the analysis showed the following range of concentration for the selected metals Ca (532.83-143880.3 ppm, Cu (65.46-212.65 ppm, Mn (1006.88-11099.87 ppm, Pb (0.33-1.9 ppm and V (100.57-199.95 ppm. In addition, calculation of Enrichment Factors (Efs, Pollution Index (PIs and Geoaccumulation Index (Igeos was done. The calculated results of Igeo and EF of heavy metals revealed the order of are Mn>Cu>Pb>Ca>V. EF of Mn and Cu record higher percentage values indicating that there is considerable Mn and Cu pollution, which mainly originate from activities of the factory.

  12. Hybrid life cycle assessment comparison of colloidal silica and cement grouted soil barrier remediation technologies

    International Nuclear Information System (INIS)

    Highlights: ► We use LCA to study environmental impacts of grouting techniques for site remediation. ► We consider colloidal silica permeation grouting and cement jet grouting. ► Manufacturing and transportation contribute significantly in all impact categories. ► Activity outside of direct site activity is important in assessing impacts. ► LCA can be used to consider sustainability criteria for remediation decisions. -- Abstract: Site remediation involves balancing numerous costs and benefits but often neglects the environmental impacts over the entire project life cycle. Life cycle assessment (LCA) offers a framework for inclusion of global environmental “systems-level” decision metrics in combination with technological and cost analysis. We compare colloidal silica (CS) and cement grouted soil barrier remediation technologies for soils affected by low level radionuclides at a U.S. Superfund site using hybrid LCA methods. CS is a new, high performance grouting material installed using permeation grouting techniques. Cement, a more traditional grouting material, is typically installed using jet grouting techniques. Life cycle impacts were evaluated using the US EPA TRACI 2 model. Results show the highest life cycle environmental impacts for the CS barrier occur during materials production and transportation to the site. In general, the life cycle impacts for the cement barrier were dominated by materials production; however, in the extreme scenario the life cycle impacts were dominated by truck transportation of spoils to a distant, off-site radioactive waste facility. It is only in the extreme scenario tested in which soils are transported by truck (Option 2) that spoils waste transport dominates LCIA results. Life cycle environmental impacts for both grout barriers were most sensitive to resource input requirements for manufacturing volumes and transportation. Uncertainty associated with the efficacy of new technology such as CS over its required

  13. Lithological and land-use based assessment of heavy metal pollution in soils surrounding a cement plant in SW Europe.

    Science.gov (United States)

    Cutillas-Barreiro, Laura; Pérez-Rodríguez, Paula; Gómez-Armesto, Antía; Fernández-Sanjurjo, María José; Álvarez-Rodríguez, Esperanza; Núñez-Delgado, Avelino; Arias-Estévez, Manuel; Nóvoa-Muñoz, Juan Carlos

    2016-08-15

    We study the influence of phasing out a cement plant on the heavy metal (Hg, Pb and Cr) content in the surrounding soils, taking into account factors often neglected, such as contributions due to local lithology or land use. The range of total Hg was 10-144µg kg(-1), reaching up to 41 and 145mgkg(-1) for total contents of Pb and Cr, respectively. Forest soils showed higher concentration of Hg than prairie soils, indicating the importance of land use on the accumulation of volatile heavy metals in soils. In forest soils, total Hg showed a trend to decrease with soil depth, whereas in prairie soils the vertical pattern of heavy metal concentrations was quite homogeneous. In most cases, the distance to the cement plant was not a factor of influence in the soils content of the analyzed heavy metals. Total Pb and Cr contents in soils nearby the cement plant were quite similar to those found in the local lithology, resulting in enrichment factor values (EF's) below 2. This suggests that soil parent material is the main source of these heavy metals in the studied soils, while the contribution of the cement plant to Pb and Cr soil pollution was almost negligible. On the contrary, the soils surrounding the cement plant accumulate a significant amount of Hg, compared to the underlying lithology. This was especially noticeable in forest soils, where Hg EF achieved values up to 36. These results are of relevance, bearing in mind that Hg accumulation in soils may be an issue of environmental concern, particularly in prairie soils, where temporal flooding can favor Hg transformation to highly toxic methyl-Hg. In addition, the concurrence of acid soils and total-Cr concentrations in the range of those considered phytotoxic should be also stressed. PMID:27099999

  14. UNSTABLE INTERTROCHANTERIC FRACTURE IN ELDERLY TREATED WITH CEMENTED BIPOLAR HEMIARTHROPLASTY AND TROCHANTERIC RECONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Jagadeesh Kumar

    2015-06-01

    Full Text Available INTRODUCTION : Unstable inter - trochanteric fracture in the geriatric population is a common injury and is associated with poor bone quality, excessive collapse, loss of fixation, and cut - out of the lag screw, are the common problems of attempts to fix these fractures. Pr esent study is an attempt to evaluate the functional outcome of primary cemented bipolar hemiarthroplasty and trochanter reconstruction in these patients. MATERIALS AND METHOD S : This prospective study included 30 cases of elderly osteoporotic patients with mean age of 65.4 years who sustained comminuted inter - trochanteric femur fracture treated with cemented bipolar hemiarthroplasty& tension band wiring for greater trochanter rec onstruction. It is an essential technical step to avoid complication like abductor lurch gait. W e here describe a technique of reconstruction and fixation of greater trochanter using tension band wiring in figure of eight pattern. The patients were followe d up at six week, three month, six month and one year postoperatively and assessed using Harris Hip Score (HHS. RESULTS : The mean HHS score was was 85.6+SD 9.5 (range from 74 to 96. B y the end of one year. The main clinical measures were early post - opera tive full weight bearing, post - operative complication & functional outcome. The time to full weight bearing, the rate of post - operative complications & functional outcome was significantly better in cemented bipolar arthroplasty group . DISCUSSION : The chan ges in HHS up to six months periods are much greater which starts showing a stable trend thereafter. Fair to good scores were observed in all the patients. The purpose of its use was that while Harris Hip Score (HHS provides information on a multitude of factors. Superficial infection in 2 patients, anterior thigh pain in a patient, shortening less than 2cms in 2 patients, abductor lurch in a patient are the complications noted in post - operative period, but no patient required

  15. Study of elastic-plastic damage model of cement consolidated soil with high organic content

    Institute of Scientific and Technical Information of China (English)

    CHEN Huie; WANG Qing; CAI Keyi

    2009-01-01

    On the basis of elastic-plastic damage model of cement consolidated soil, the authors took organic contents into reasonable damage variable evolution equation in order to seek relation between the organic contents and parameters in the equation, and established the elastic-plastic damage model of cement consolidated soil considering organic contents. The results show that the parameters change correspondingly with difference of the organic contents. The higher the organic contents are, the less the valves of the parameters such as elastic modulus (E), material parameters (K, n) and damage evolution parameter (ε) become, but the larger strain damage threshold value (εd) of the sample is. Meanwhile, the calculation results obtained from established model are compared with the test data in the condition of common indoors test, which is testified with reliability.

  16. Experimental study on interaction mechanism of small H-beams and a soil-cement retaining wall

    Institute of Scientific and Technical Information of China (English)

    WANG Suo-rong; CAO Bao-fei

    2008-01-01

    Small H-beams such as the No.14-20 I-steel can be inserted into soil-cement retaining walls to form small H-beam soil-cement compound walls, functioning both as a retaining wall and a cutoff wall for braced structure excavations. Being different from the mixed soil-cement wall (SMW), the interaction between soil-cement and small H-steel is very good. We have carried out a series of bending experiments on small H-beams in soil-cement model compound beams to study the mechanism of interactions. The results show that the interaction between H-beams and soil-cement is very good, whether the H-beam is single or double. Joint forms of double H-beams at one end have little effect on both the contribution coefficient and on ultimate deflection before crack-ing. But after cracking, the joint forms greatly affect the contribution coefficient. We conclude that the rigid joint girder for double H-beams is a better choice in practice.

  17. Studies on parallel seismic testing for integrity of cemented soil columns

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The principle and process of parallel seismic (PS) testing for the integrity testing of cemented soil columns are introduced in this paper. A three-dimensional (3D) finite element model (FEM) for the pile-soil system is established for impulse responses. Under saturated soil or unsaturated soil condition, several vibrating velocity-time histories at different depths in parallel hole are obtained based on the numerical simulation. It shows that the length of the pile and the one-dimensional (ID) P-wave velocity in the pile can be determined easily from the features of the mentioned velocity-time histories. By examining the slopes of the first arrival time plotted versus depth or the depth where the amplitude of the first arrival significantly decreases, the length of the pile can be determined. The effects of the 3D P-wave propagation through the saturated soil and the defect of the cemented soil column on the velocity-time histories are also investigated.

  18. Sustainable shells: New African vaults built with soil-cement tiles

    OpenAIRE

    Ramage, Michael H.; Ochsendorf, John A.; Rich, Peter

    2010-01-01

    p. 1512-1520 The Mapungubwe National Park Interpretive Centre, South Africa achieves economy of means, social improvement and low environmental impact in a remote World Heritage site. This paper outlines the design methodology and construction process for a series of thin shell domes and vaults in rural South Africa. We use the Valencian tradition of tile vaulting, a 700-year-old construction system, to create lightweight and durable buildings from thin soil-cement bricks. T...

  19. Simplified method for predicating consolidation settlement of soft ground improved by floating soil-cement column

    Institute of Scientific and Technical Information of China (English)

    龚晓南; 田效军; 胡文韬

    2015-01-01

    A simplified method is presented for predicting consolidation settlement of soft ground improved by floating soil−cement column on the basis of double soil-layer consolidation theory. Combining the axisymmetric consolidation model and equal strain assumption, the governing equation was derived for the consolidation of clayey subsoil reinforced by soil−cement column. By modifying the boundary condition of the interface between the improved layer and underlying layer on seepage and pore-water pressure, the analytical solution of consolidation of soft ground improved by floating soil−cement column was developed under depth-dependent ramp load. The results of the parameter analysis of consolidation behavior show that the consolidation rate is closely related with the depth replacement ratio by the column and the permeability of upper layer. The influence of column−soil constrained modulus ratio and radius ratio of the influence zone to the column on consolidation is also affected by depth replacement ratio. The column−soil total stress ratio increases with time and approaches the final value accompanied with the dissipation of excess pore water pressure.

  20. Assessment of the Severity of CO2 Emission from Anthill Soils Used as Replacement for Shale in Cement Manufacture

    Directory of Open Access Journals (Sweden)

    Ogunfayo I. K.

    2012-12-01

    Full Text Available This paper assessed the replacement of shale in the production of cement with anthill soil. It also looked into the severity of carbon (IV oxide (CO2 emission of the anthill soil during the production of the cement. This was compared with that emitted when shale alone is used. Various tests were carried out on the anthill soil, shale and limestone. The test results were analysed and it was discovered that the emission of carbon (II oxide gas using anthill soil is benign when compared to that of shale.

  1. An assessment of post-remediation changes in sediment chemistry partitioning in an S/S treated soil.

    Science.gov (United States)

    Cutter, S.; MacLeod, C. L.; Canning, K.; Carey, P. J.; Hills, C. D.

    2003-04-01

    The Astra Pyrotechnics plant located in the Dartford Marshes, Kent, UK was the site of a field trial utilizing cement stabilization/solidification (S/S) in September 2000. A hotspot containing 35% copper and several thousand part per million lead and zinc was treated in order to trial an new form of cement stabilization (accelerated carbonation technology or ACT) developed by the Centre for Contaminated Land Remediation. A 10 by 20 meter plot was divided into 4 cells into which untreated, OPC (ordinary Portland cement) treated, Envirocem (a Lafarge special cement) treated and ACT treated soil was placed. Each cell has a leachate collection system and the leachate is monitored monthly. In August 2003, 24 cm cores were collected from each cell. These cores were analysed to determine changes in sediment chemistry and metal partitioning characteristics. Sediment chemistry was determined using an aqua regia digestion followed by ICP OES analysis. The CISMED extraction procedure was used to examine partitioning changes. The contaminant concentrations in the leachates remain below UK drinking water standards. However, seasonal cyclicity is observed with an increase of metals in the leachates during winter months. The sediment cores were analysed for Ca, Cr, Cu, Fe, K, Mn, Mg, Na, Ni, Pb and Zn. Only the untreated cell showed any discernable changes in metal concentration with depth. The S/S treated cells show no trends although differences in partitioning between the cells is observed.

  2. Morphological properties of surface-treated carbon nanotubes in cement-based composites.

    Science.gov (United States)

    Wang, Baomin; Han, Yu; Zhang, Tingting

    2012-11-01

    The morphological properties of the multi-walled carbon nanotubes (MWCNTs) reinforced Portland cement composites were investigated. MWCNTs with addition of up to 0.15 wt% of cement were incorporated to Portland cement with a water to cement ratio of 0.35. The porosity and pore size distribution of the composites were measured by mercury intrusion porosimetry (MIP), and the results indicate that the cement doped with MWCNTs obtained lower porosity and concentrated pore size distribution. The microstructure was analyzed by field emission scanning electron microscopy (FE SEM) and energy dispersive spectroscopy (EDS). It is shown that MWCNTs act as bridges and networks across cracks and voids. PMID:23421224

  3. Application Technology of Foamed Cement Lightweight Soil%气泡混合轻质土的应用技术

    Institute of Scientific and Technical Information of China (English)

    王志斌

    2014-01-01

    气泡混合轻质土是土建工程领域中近年开发的一种新型轻质填土材料,将其应用于软基处理、冻土保护、冻胀翻浆防治、桥台台背填筑等,可提高公路的建设质量与服务使用水平,降低养护成本。基于此,重点论述了轻质土的冻胀与热传导理论、材料特性,以及其在冻土地基保护和道路冻胀翻浆中的应用,具有一定的理论和实际意义。%Foamed cement lightweight soil is a new type of lightweight fill material,which can improve construction quality, service level, and decrease maintenance cost if being used in soft foundation treat-ment, frozen soil protection, frost heaving boiling prevention and bridge abutment filling. The article elabo-rates theory of frost heaving and heat conduction of lightweight soil, material features, and its application in frozen soil subgrade protection and road frost heaving boiling, which has certain theoretical and practi-cal significance.

  4. The Effect of Polymer-Cement Stabilization on the Unconfined Compressive Strength of Liquefiable Soils

    Directory of Open Access Journals (Sweden)

    Ali Ateş

    2013-01-01

    Full Text Available Soil stabilization has been widely used as an alternative to substitute the lack of suitable material on site. The use of nontraditional chemical stabilizers in soil improvement is growing daily. In this study a laboratory experiment was conducted to evaluate the effects of waterborne polymer on unconfined compression strength and to study the effect of cement grout on pre-venting of liquefiable sandy soils. The laboratory tests were performed including grain size of sandy soil, unit weight, ultrasonic pulse velocity, and unconfined compressive strength test. The sand and various amounts of polymer (1%, 2%, 3%, and 4% and cement (10%, 20%, 30%, and 40% were mixed with all of them into dough using mechanical kneader in laboratory conditions. Grouting experiment is performed with a cylindrical mould of  mm. The samples were subjected to unconfined compression tests to determine their strength after 7 and 14 days of curing. The results of the tests indicated that the waterborne polymer significantly improved the unconfined compression strength of sandy soils which have susceptibility of liquefaction.

  5. Numerical computation of anti-liquefaction effect of lattice-type cement-mixed soil countermeasure

    Institute of Scientific and Technical Information of China (English)

    高玉峰; 杨雪玲; 沈扬; 周源

    2008-01-01

    Continuous soil-cement wall confinement method to resist liquefaction is a new kind of process. However, whether it also has a good effect on anti-liquefaction or not needs to be urgently answered for earthquake engineering. Quiet boundary is adopted on the lateral face while free field boundary is employed at the bottom. Byrne model on dynamic pore water pressure generation is accepted and natural seismic wave EI Centro whose peak acceleration is adjusted to 0.2 g in proportion is used for input. A double-layer foundation with sandy soil in the upper portion while clay soil in the lower part is chosen as the calculation model, which is 30 m in length and 20 m in width. The groundwater level is on the ground surface. Excess pore water pressure rate is considered as a liquefaction index in the three-dimensional non-linear earthquake response computation. The anti-liquefaction effectiveness and its influencing factors, such as confinement element area are studied. For the natural double-layer foundation, it is liquefied when the excess pore water pressure rate reaches 1.0 under the seismic load. Under the same earthquake load, the peak excess pore water pressure reduces to 0.56 after adopting reinforcement of the continuous soil-cement wall, which is 46% lower than before. It indicates that continuous soil-cement wall confinement method can attain the purpose of anti-liquefaction. Accordingly, it can be a sort of engineering measure to carry on the anti-liquefaction foundation treatment.

  6. Earthworm (Eisenia andrei) Avoidance of Soils Treated with Cypermethrin

    OpenAIRE

    Mara M. de Andréa; Sousa, Ana Paula A. de

    2011-01-01

    The pyrethroid insecticide cypermethrin is used for agricultural and public health campaigns. Its residues may contaminate soils and the beneficial soil organisms, like the earthworms, that may ingest the contaminated soil particles. Due to its ecological relevance, earthworms Eisenia andrei/fetida have been used in different ecotoxicological tests. The avoidance of soils treated with cypermethrin by compost worms Eisenia andrei was studied here as a bioindicator of the influence of treatment...

  7. Determination of Heavy Metal in Agricultural Soils near and Far From the Cement Factory in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Rezaeian

    2016-08-01

    Full Text Available Background: Heavy metals (HMs are one of the most important polluting substances emitted to the environment during cement production. Tehran Cement Factory located in the southeastern of Tehran, Iran, closer to agricultural lands cultivates alfalfa, barley, and maize as feed. The objective of the study was to determine the concentration of HMs in agricultural soils. Methods: Thirty six soil samples were collected from two regions of Aminabad (close to the cement factory and Varamin (far from cement factory in 2015. The samples were taken from a depth of 0-15 cm and analyzed to determine their HM (zinc, lead, cadmium and chromium by atomic absorption spectrophotometry. Other relevant parameters of soil were evaluated, such as; pH, EC, TOM. Results: The concentration of HMs in both regions was as follows: Pb> Zn > Cr > Cd. Generally, the soil alfalfa, barley and maize, there was no significant difference. Conclusion: These data provide information on HM accumulations in agricultural soils and allow us to identify sources of pollution. In the industrial area due to the proximity to cement factory, concentration of zinc, lead, chromium, pH and EC were more than non-contaminated areas.

  8. Resistance to bond degradation between dual-cure resin cements and pre-treated sintered CAD-CAM dental ceramics

    Science.gov (United States)

    Osorio, Raquel; Monticelli, Francesca; Osorio, Estrella; Toledano, Manuel

    2012-01-01

    Objective: To evaluate the bond stability of resin cements when luted to glass-reinforced alumina and zirconia CAD/CAM dental ceramics. Study design: Eighteen glass-infiltrated alumina and eighteen densely sintered zirconia blocks were randomly conditioned as follows: Group 1: No treatment; Group 2: Sandblasting (125 µm Al2O3-particles); and Group 3: Silica-coating (50 µm silica-modified Al2O3-particles). Composite samples were randomly bonded to the pre-treated ceramic surfaces using different resin cements: Subgroup 1: Clearfil Esthetic Cement (CEC); Subgroup 2: RelyX Unicem (RXU); and Subgroup 3: Calibra (CAL). After 24 h, bonded specimens were cut into 1 ± 0.1 mm2 sticks. One-half of the beams were tested for microtensile bond strength (MTBS). The remaining one-half was immersed in 10 % NaOCl aqueous solution (NaOClaq) for 5 h before testing. The fracture pattern and morphology of the debonded surfaces were assessed with a field emission gun scanning electron microscope (FEG-SEM). A multiple ANOVA was conducted to analyze the contributions of ceramic composition, surface treatment, resin cement type, and chemical challenging to MTBS. The Tukey test was run for multiple comparisons (p < 0.05). Results: After 24 h, CEC luted to pre-treated zirconia achieved the highest MTBS. Using RXU, alumina and zirconia registered comparable MTBS. CAL failed prematurely, except when luted to sandblasted zirconia. After NaOClaq storage, CEC significantly lowered MTBS when luted to zirconia or alumina. RXU decreased MTBS only when bonded to silica-coated alumina. CAL recorded 100 % of pre-testing failures. Micromorphological alterations were evident after NaOClaq immersion. Conclusions: Resin-ceramic interfacial longevity depended on cement selection rather than on surface pre-treatments. The MDP-containing and the self-adhesive resin cements were both suitable for luting CAD/CAM ceramics. Despite both cements being prone to degradation, RXU luted to zirconia or untreated or

  9. Performances of hydrated cement treated crushed rock base for Western Australian roads

    Directory of Open Access Journals (Sweden)

    Suphat Chummuneerat

    2014-12-01

    Full Text Available The resilient modulus (RM of hydrated cement treated crushed rock base (HCTCRB affected by amount of hydration periods, compaction and dryback processes was presented using repeated load triaxial tests. The related trends of RM corresponding to the different hydration periods still cannot be concluded. Instead, It is found that the moisture content plays more major influence on the RM performance. Higher additional water during compaction of HCTCRB, even at its optimum moisture content and induced higher dry density, led to the inferior RM performance compared to the sample without water addition. The RM of damper samples can be improved through dryback process and superior to that of the sample without water addition at the same moisture content. However, the samples without water addition during compaction deliver the comparable RM values even its dry density is lower than the other two types. These results indicate the significant influence of moisture content to the performances of HCTCRB with regardless of the dry density. Finally, the experimental results of HCTCRB and parent material are evaluated with the K-θ model and the model recommended by Austroads. These two models provide the excellent fit of the tested results with high degree of determination.

  10. Runoff on Pavements of Soil-Cement Blocks – an Experimental Boarding

    Directory of Open Access Journals (Sweden)

    Zegarra-Tarqui Jorge Luis

    2015-01-01

    Full Text Available The article evaluates the reduction of runoff in pavements constructed with rectangular blocks of soil-cement. The tests were conducted in a pilot pavement built with soil-cement blocks, seated in a metal box of 50 cm × 50 cm (area = 2500 cm2, with declivities of 1%, 3% and 5%. Mean intensities of 76.9 mm / I 117.7 mm / h were used, values close to the intensities calculated by intensity-frequency-duration (i-f- -d equation of the city of Salvador, Brazil, for return periods of 2 and 5 years, respectively. The medium runoff coefficient was C = 0.61, this value is close to the coefficient of pavement with rectangular blocks (C = 0.6 and it has a lower value than the coefficient for concrete block pavement (C = 0.78. On the other hand, considering that areas with more than 2500 cm2 are constituted by coupling of area units of 50 cm × 50 cm, the splash losses are part of the runoff, obtaining the coefficient Csuperficial + splashing, which showed values in the 0.74 to 0.89 range, these values were found close to the coefficient of concrete block pavement (C = 0.78 and below the concrete pavement (C = 0.95, respectively, but factors such as displacement time of runoff on surface, depressions on the surface, roughness of pavement, evaporation and others, should reduce this value. Then, the pavement of soil-cement blocks can be considered in the category of semi-permeable for the area size used.

  11. REMEDIATION OF POLLUTED SOILS BY UTILIZING HYDROTHERMALLY TREATED CALCAREOUS FLY ASHES

    Institute of Scientific and Technical Information of China (English)

    A. Moutsatsou; V. Protonotarios

    2006-01-01

    This paper investigates a treated fly ash to act as a synthetic zeolite to remediate soils polluted with heavy metals and metalloids (As, Pb, Cu, Zn, Fe, Cd and Mn). Four types of such 'zeolites' were synthesized by hydrothermal treatment of a calcareous fly ash derived from Greek lignite-fired power plants: two with excess of sodium hydroxide in a a former mining site at Lavrion, Greece. Mobilization and transfer of metals to the retention agents was effected by using HCl aq 1M, with satisfactory results with respect to As, Pb, Cu, Mn and Cd. The great variety of metal complexes in soil was found to be of major importance for the effectiveness of the overall process. The final products were solidified either on their own, or by using additives such as lime and cement.

  12. THE STATE-OF-ART FOR CONSTRUCTION OF SOIL-CEMENT AND STIFFENED SOIL-CEMENT MIXING PILES%水泥土及加劲水泥土搅拌桩施工技术发展现状

    Institute of Scientific and Technical Information of China (English)

    史佩栋; 张美珍

    2001-01-01

    This paper summarizes the state-of-art of the soil-cement and the stiffened soil-cement mixing piles both at home and abroad . It highlights their recent applications in China, the proportion of the curing agent, water-cement ratio, H-section pull-out machine and the vertical load bearing capacity of compressibility of the piles etc.%综述了水泥土搅拌桩及加劲水泥土搅拌桩在国内外的技术发展现状,着重阐述了近年在我国的各种应用,以及固化剂的配合比与水灰比,H型钢起拔机,桩的竖向抗压承载力等。

  13. Earthworm (Eisenia andrei Avoidance of Soils Treated with Cypermethrin

    Directory of Open Access Journals (Sweden)

    Mara M. de Andréa

    2011-11-01

    Full Text Available The pyrethroid insecticide cypermethrin is used for agricultural and public health campaigns. Its residues may contaminate soils and the beneficial soil organisms, like the earthworms, that may ingest the contaminated soil particles. Due to its ecological relevance, earthworms Eisenia andrei/fetida have been used in different ecotoxicological tests. The avoidance of soils treated with cypermethrin by compost worms Eisenia andrei was studied here as a bioindicator of the influence of treatment dosage and the pesticide formulation in three different agricultural soils indicated by the Brazilian environmental authorities for ecotoxicological tests. This earthworms’ behavior was studied here as a first attempt to propose the test for regulation purposes. The two-compartment test systems, where the earthworms were placed for a two-day exposure period, contained samples of untreated soil alone or together with soil treated with technical grade or wettable powder formulation of cypermethrin. After 48 h, there was no mortality, but the avoidance was clear because all earthworms were found in the untreated section of each type of soil (p < 0.05. No differences were found by the Fisher’s exact test (p ≤ 1.000 for each soil and treatment, demonstrating that the different soil characteristics, the cypermethrin concentrations and formulation, as well as the smaller amounts of soil and earthworms did not influence the avoidance behavior of the earthworms to cypermethrin. The number and range of treatments used in this study do not allow a detailed recommendation of the conditions applied here, but to the best of our knowledge, this is the first reported attempt to identify the avoidance of pesticide treated tropical soils by earthworms.

  14. Earthworm (Eisenia andrei) Avoidance of Soils Treated with Cypermethrin

    Science.gov (United States)

    de Sousa, Ana Paula A.; de Andréa, Mara M.

    2011-01-01

    The pyrethroid insecticide cypermethrin is used for agricultural and public health campaigns. Its residues may contaminate soils and the beneficial soil organisms, like the earthworms, that may ingest the contaminated soil particles. Due to its ecological relevance, earthworms Eisenia andrei/fetida have been used in different ecotoxicological tests. The avoidance of soils treated with cypermethrin by compost worms Eisenia andrei was studied here as a bioindicator of the influence of treatment dosage and the pesticide formulation in three different agricultural soils indicated by the Brazilian environmental authorities for ecotoxicological tests. This earthworms’ behavior was studied here as a first attempt to propose the test for regulation purposes. The two-compartment test systems, where the earthworms were placed for a two-day exposure period, contained samples of untreated soil alone or together with soil treated with technical grade or wettable powder formulation of cypermethrin. After 48 h, there was no mortality, but the avoidance was clear because all earthworms were found in the untreated section of each type of soil (p < 0.05). No differences were found by the Fisher’s exact test (p ≤ 1.000) for each soil and treatment, demonstrating that the different soil characteristics, the cypermethrin concentrations and formulation, as well as the smaller amounts of soil and earthworms did not influence the avoidance behavior of the earthworms to cypermethrin. The number and range of treatments used in this study do not allow a detailed recommendation of the conditions applied here, but to the best of our knowledge, this is the first reported attempt to identify the avoidance of pesticide treated tropical soils by earthworms. PMID:22247652

  15. Development of sorption database (JAEA-SDB). Update of sorption data including soil and cement systems

    International Nuclear Information System (INIS)

    Sorption of radionuclides in buffer materials (bentonite) and rocks is the key process in the safe geological disposal of radioactive waste, because migration of radionuclides in this barrier is expected to be controlled by sorption processes. Distribution coefficient (Kd) is therefore important parameter in the performance assessment (PA) of geological disposal. The sorption database including extensive compilations of Kd data measured by batch sorption experiments plays key roles in PA-related Kd setting and predictive model development under a variety of geochemical conditions. For this purpose, Japan Atomic Energy Agency (JAEA) has developed sorption database (JAEA-SDB) as an important basis for the PA of high-level radioactive waste disposal. This sorption database was firstly developed for the H12 PA, and was improved and updated in view of potential future data needs, focusing on assuring the desired quality level and testing the usefulness of the databases for possible applications to PA-related parameter setting. The present report focuses on updating of the sorption database (JAEA-SDB) by adding Kd data for various systems including soil and cement systems, to apply JAEA-SDB for the PA-related Kd setting for disposal of low level radioactive wastes including TRU wastes and the evaluation of radionuclide transport in surface soil systems. The updated data includes Kd data for soil and cement systems extracted from mainly previous published database, and Kd data related to our recent activities on the Kd setting and mechanistic model development. As a result, 16,000 Kd data from 334 references are added, total Kd values in the JAEA-SDB are about 46,000. The updated JAEA-SDB is expected to make it possible to obtain quick overview of the available data, and to have suitable access to the respective data for the performance assessment of various types of radioactive waste. (author)

  16. Use of Factory-Waste Shingles and Cement Kiln Dust to Enhance the Performance of Soil Used in Road Works

    Directory of Open Access Journals (Sweden)

    Aly Ahmed

    2009-01-01

    Full Text Available An experimental work was conducted to study the use of factory-waste roof shingles to enhance the properties of fine-grained soil used in road works. Cement kiln dust (CKD, a cogenerated product of Portland cement manufacturing, was used as a stabilizing agent while the processed shingles were added to enhance the soil tensile strength. The effects of shingles on strength and stability were evaluated using the unconfined compressive strength, splitting tensile strength, and California Bearing Ratio (CBR tests. The results showed that the use of CKD alone resulted in a considerable increase in the unconfined compressive strength but had a small effect on the tensile strength. The addition of shingles substantially improved the tensile strength of the stabilized soil. A significant reduction in the capillary rise and a slight decrease in the permeability were obtained as a result of shingle addition. An optimal shingle content of 10% is recommended to stabilize the soil.

  17. Electrodialytically treated MSWI APC residue as substitute for cement in mortar

    DEFF Research Database (Denmark)

    Kirkelund, Gunvor Marie; Geiker, Mette Rica; Jensen, Pernille Erland

    2014-01-01

    /or electrodialytic remediation, were used in Portland cement mortar. Mortar bars with 15 % weight replacement of cement by APC residues showed compressive strengths up to 40 MPa after 28/32 days. Heavy metal and salt leaching from both crushed and monolithic mortars with APC residues was generally similar...... and comparable to both the reference mortar and mortar with coal fly ash. These results indicate that electrodialytic remediation could be used a pre-treatment method for MSWI APC residues prior to reuse in mortar....

  18. Phase I - Laboratory Study Effects of Cement Grout Structures on Colloid Formation from SRS Soils

    International Nuclear Information System (INIS)

    Studies were conducted to better understand the influence of grout structures and fills on colloid formation. Low-Level Waste is disposed in concrete vaults and trenches at the E-Area Low-Level Waste Facility (LLWF). Two types of enhanced trench disposal are approved for use including; Intimately-Mixed Cement-Stabilized waste forms, such as Ashcrete and Blowcrete resulting from operation of the Consolidated Incinerator Facility, and Cement-Stabilized Encapsulated waste, where waste forms (e.g., contaminated equipment) will be surrounded by a grout or other cementitious material. The presence of concrete structures and process of grouting in trenches are expected to generate colloids, both from the grout itself and as a result of the interactions of these cementitious materials and their degradation products with the surrounding soils. The extent of occurrence, mobility, and influence on contaminant transport of colloidal materials in aquifer systems is the subject of this study. The intent of this study is not to modify the PA but to aid in our understanding of the significance of this phenomenon. Information generated in this study will help in considering whether colloid-enhanced contaminant migration should be considered in establishing waste acceptance criteria and in the design and development of waste disposal systems

  19. Design and construction of treatment of soft soil foundation with cement mixing pile%采用水泥搅拌桩处置软土地基的设计与施工

    Institute of Scientific and Technical Information of China (English)

    王东刚

    2011-01-01

    To solve the problems of low bearing capacity of highway soft soil foundation or bigger differential settlement,the first-class highway of Shiqigou to Qingshuihe section in 109 national road used cement mixing pile to treat soft soil foundation which provides a reference for the application of cement mixing pile on eliminating the harm of soft soil foundation in Inner Mongolia autonomous.%为了解决公路软土地基承载力过低与较大的不均匀沉降问题,以国道109线十七沟-清水河段一级公路为依托工程,采用水泥搅拌桩处置软土地基,为内蒙古自治区应用水泥搅拌桩消除软土地基的危害提供一定的参考。

  20. Mixture optimization of cement treated demolition waste with recycled masonry and concrete

    NARCIS (Netherlands)

    Xuan, D.X.; Houben, L.J.M.; Molenaar, A.A.A.; Shui, Z.H

    2011-01-01

    Due to environmental reasons and the shortage of natural resources, it is greatly valuable to recycle construction and demolition waste (CDW) as much as possible. One of effective ways to reuse more CDW is to produce a cemented road base material. The recycled CDW however is a mix of recycled masonr

  1. Investigation of combined effect of mixture variables on mechanical properties of cement treated demolition waste

    NARCIS (Netherlands)

    Xuan, D.; Houben, L.J.M.; Molenaar, A.A.A.; Shui, Z.

    2012-01-01

    One of high efficient ways to reuse the recycled construction and demolition waste (CDW) is to consider it as a road base material. The recycled CDW however is mainly a mix of recycled masonry and concrete with a wide variation in composition. This results that the mechanical properties of cement tr

  2. Outcomes of osteoporotic trochanteric fractures treated with cement-augmented dynamic hip screw

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar Gupta

    2012-01-01

    Full Text Available Background: Dynamic hip screw (DHS has been the standard treatment for stable trochanteric fracture patterns, but complications of lag screw cut out from a superior aspect, due to inadequate bone anchorage, occur frequently in elderly osteoporotic patients. Polymethylmethacrylate (PMMA has been used as an augmentation tool to facilitate fixation stability in cadaveric femora for biomechanical studies and in pathological fractures. However, there are very few reports on the utilization of PMMA cement to prevent these complications in fresh intertrochanteric fractures. A prospective study was conducted to evaluate the outcome and efficacy of PMMA augmented DHS in elderly osteoporotic patients with intertrochanteric fractures. Materials and Methods: The study included 64 patients (AO type31-A2.1 in eight, A2.2 in 29, A2.3 in 17 patients, and 31-A3.1 in five, A3.2 in three, and A3.3 in two patients with an average age of 72 years (60 − 94 years of which 60 were available for final followup. PMMA augmentation of DHS was performed in all cases by injecting PMMA cement into the femoral head with a custommade gun designed by the authors. The clinical outcome was rated as per the Salvati and Wilson scoring system at the time of final followup of one year. Results were graded as excellent (score > 31, good (score 24 − 31, fair (score 16 − 23, and poor (score < 16. Results: Fracture united in all patients and the average time to union was 13.8 weeks (range 12 − 16 weeks. At an average followup of 18 months (range 12 − 24 months, no incidence of varus collapse or superior screw cut out was observed in any of the patients in spite of weightbearing ambulation from the early postoperative period. There was no incidence of avascular necrosis (AVN or cement penetration into the joint in our series. Most of the patients were able to regain their prefracture mobility status with a mean hip pain score of 8.6. Conclusion: Cement augmentation of DHS appears

  3. Soil Chemistry after Irrigation with Treated Wastewater in Semiarid Climate

    Directory of Open Access Journals (Sweden)

    Pedro Carlos Pacheco de Oliveira

    2016-01-01

    Full Text Available ABSTRACT Soil irrigation using treated wastewater in the Brazilian semiarid region is a promising practice as this area currently faces water scarcity and pollution of water resources by domestic sewage. The aim of this study was to evaluate the use of treated wastewater in drip irrigation and its effect on the chemistry of soil cultivated with squash (Cucurbita maxima Duch. Coroa IAC and to verify whether there was an increase in soil salinity under a semiarid climate. The experiment was conducted for 123 days on a farm close to the sewage treatment plant, in a randomized block design with five treatments and four replications. The treatments consisted of two irrigation water depths (100 and 150 % of the evapotranspiration, two applications of gypsum to attenuate wastewater sodicity (0 and 5.51 g per plant, and a control treatment with no application of wastewater or gypsum. During the experiment, treated wastewater and soil gravitational water, at a depth of 0.40 m, were collected for measurement of Na+, K+, Ca2+, Mg2+, NO−3, NH4+, Cl− , alkalinity, electrical conductivity, pH and sodium adsorption ratio. At the end of the experiment, soil samples were collected at depths of 0.00-0.10, 0.10-0.20, and 0.20-0.40 m; and pH, total N, organic C, exchangeable cations and electrical conductivity of the saturation extract (CEs were analyzed. Besides an increase in pH and a reduction in total N, the irrigation with wastewater reduces soil salinity of the naturally salt-rich soils of the semiarid climate. It also led to soil sodification, in spite of the added gypsum, which indicates that irrigation with wastewater might require the addition of greater quantities of gypsum to prevent physical degradation of the soil.

  4. Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters

    Directory of Open Access Journals (Sweden)

    A. Morugán-Coronado

    2013-03-01

    Full Text Available The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. These indices represent the balance reached among properties in "steady state" soils. This study was carried out in four study sites from SE Spain irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.

  5. Greater Trochanter Reconstruction in Unstabl Intertrochanteric Fractures Treated With Cemented Bipolar Hemiarthroplasty: A Technical Note.

    Science.gov (United States)

    Subramanian, G V; Guravareddy, A V; Reddy, Anil Kumar K R; Chiranjeevi, T

    2012-01-01

    Cemented Bipolar arthroplasty is an established method for treatment of comminuted Intertrochanteric fractures. Reconstruction of greater trochanter is an essential technical step to avoid complications like abductor lurch gait. We here describe a technique of reconstruction and fixation of greater trochanter using cancellous screws with wide washers made of reconstruction plate and tension band wiring. This gives a stable fixation of greater trochanter and avoids cut out, slippage of implants. PMID:27298870

  6. Greater Trochanter Reconstruction in Unstabl Intertrochanteric Fractures Treated With Cemented Bipolar Hemiarthroplasty: A Technical Note

    OpenAIRE

    Subramanian, G V; Guravareddy, A V; Reddy, Anil Kumar K R; Chiranjeevi, T.

    2012-01-01

    Cemented Bipolar arthroplasty is an established method for treatment of comminuted Intertrochanteric fractures. Reconstruction of greater trochanter is an essential technical step to avoid complications like abductor lurch gait. We here describe a technique of reconstruction and fixation of greater trochanter using cancellous screws with wide washers made of reconstruction plate and tension band wiring. This gives a stable fixation of greater trochanter and avoids cut out, slippage of implants.

  7. Kinetics of Phosphate Release from Three Phosphate-Treated Soils

    Institute of Scientific and Technical Information of China (English)

    LI Shou-Tian; ZHOU Jian-Min; WANG Huo-Yan; DU Chang-Wen; CHEN Xiao-Qin

    2005-01-01

    Phosphate release from three selected soils after treatments of 1.6 and 2.4 mmol L-1 P was investigated using sequential extractions and fitted using six kinetic models, including zero order (Z), first order (F), second order (S),parabolic diffusion (PD), two constant rate (TC), and Elovich type (ET) equations. The results showed that the rate of P release was initially rapid and then gradually declined with time. Also, P release increased with added P. Total P release followed the order: paddy soil with 2.4 mmol L-1 P > red soil with 2.4 mmol L-1 P > paddy soil with 1.6 mmol L-1 P > fluvo-aquic soil with 2.4 mmol L-1 P > fluvo-aquic with 1.6 mmol L-1 P > red soil with 1.6 mmol L-1 P. For the two P treatments P release from the paddy soils in the first extraction was 44.3% and 45.6% of total released P, respectively,which were higher than those from red and fluvo-aquic soils. The ratio of P release at the end of release time was 14.0%and 13.1% in the paddy soil treated with 1.6 and 2.4 mmol L-1 P, respectively, but only 5.1% and 9.2% in the red soil and 7.0% and 5.2% in the fluvo-aquic soil, respectively. Comparison of the coefficients of determination (R2) indicated that ET, TC, and PD equations could describe the P release data better than Z, F, and S equations.

  8. Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters

    Directory of Open Access Journals (Sweden)

    A. Morugán-Coronado

    2012-12-01

    Full Text Available The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships, the equilibrium reached and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. This study was carried out in three areas of Alicante Province (SE Spain irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.

  9. Efficiency modeling of solidification/stabilization of multi-metal contaminated industrial soil using cement and additives

    Energy Technology Data Exchange (ETDEWEB)

    Voglar, Grega E. [RDA - Regional Development Agency Celje, Kidriceva ulica 25, 3000 Celje (Slovenia); Lestan, Domen, E-mail: domen.lestan@bf.uni-lj.si [Agronomy Department, Centre for Soil and Environmental Science, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana (Slovenia)

    2011-08-30

    Highlights: {yields} We assess the feasibility of using soil S/S for industrial land reclamation. {yields} Retarders, accelerators, plasticizers were used in S/S cementitious formulation. {yields} We proposed novel S/S efficiency model for multi-metal contaminated soils. - Abstract: In a laboratory study, formulations of 15% (w/w) of ordinary Portland cement (OPC), calcium aluminate cement (CAC) and pozzolanic cement (PC) and additives: plasticizers cementol delta ekstra (PCDE) and cementol antikorodin (PCA), polypropylene fibers (PPF), polyoxyethylene-sorbitan monooleate (Tween 80) and aqueous acrylic polymer dispersion (Akrimal) were used for solidification/stabilization (S/S) of soils from an industrial brownfield contaminated with up to 157, 32,175, 44,074, 7614, 253 and 7085 mg kg{sup -1} of Cd, Pb, Zn, Cu, Ni and As, respectively. Soils formed solid monoliths with all cementitious formulations tested, with a maximum mechanical strength of 12 N mm{sup -2} achieved after S/S with CAC + PCA. To assess the S/S efficiency of the used formulations for multi-element contaminated soils, we propose an empirical model in which data on equilibrium leaching of toxic elements into deionized water and TCLP (toxicity characteristic leaching procedure) solution and the mass transfer of elements from soil monoliths were weighed against the relative potential hazard of the particular toxic element. Based on the model calculation, the most efficient S/S formulation was CAC + Akrimal, which reduced soil leachability of Cd, Pb, Zn, Cu, Ni and As into deionized water below the limit of quantification and into TCLP solution by up to 55, 185, 8750, 214, 4.7 and 1.2-times, respectively; and the mass transfer of elements from soil monoliths by up to 740, 746, 104,000, 4.7, 343 and 181-times, respectively.

  10. 浅谈水泥土强度的影响因素%Study on the factors affecting the strength of cement-soil

    Institute of Scientific and Technical Information of China (English)

    林云腾

    2011-01-01

    针对水泥土在土体加固中的广泛应用,在综合各种文献的基础上,本文重点探讨了水泥土强度的若干影响因素。主要因素有土的天然含水率、土的物理性质、有机质含量、pH值、水泥掺入比、水灰比、水泥土含水率、龄期、养护条件,明确这些因素,有利于指导水泥土设计和施工从而达到预期目的。%Because of widely using of cement-soil in the soil reinforcement,this paper focuses on a number of factors affecting cement-soil strength in the basis of summarization of the literature.The main factors are the natural soil moisture,soil physical properties,organic matter content,pH value,SO2-4,cement ratio,water-cement ratio,moisture content of soil-cement,age,curing conditions.Definition of these factors is conducive for changing various factors in the design and construction of cement-soil to achieve the intended purpose.

  11. An evaluation of the composition of soil cement bricks with construction and demolition waste - doi: 10.4025/actascitechnol.v33i2.9377

    Directory of Open Access Journals (Sweden)

    Antonio Anderson da Silva Segantini

    2011-04-01

    Full Text Available Sustainable development requires the existence of a production network that includes the reuse of construction waste for new materials. Current analysis investigates an optimal soil-cement composition made up of construction and demolition waste for the manufacture of pressed bricks. Soil-cement bricks were manufactured from construction and demolition wastes (CDW, A-4 classified fine sandy soil and cement CP II Z 32. Laboratory tests, comprising test compaction, optimum water content and maximum dry specific weight, consistency limits, grain size distribution and linear shrinkage, were made to characterize the materials researched. Compressive strength and absorption tests were also undertaken in different combinations of composition. Results showed that the application of CDW improved soil-cement qualities and reduced shrinkage of the material used.

  12. Disposal of historically contaminated soil in the cement industry and the evaluation of environmental performance.

    Science.gov (United States)

    Li, Yeqing; Zhang, Jiang; Miao, Wenjuan; Wang, Huanzhong; Wei, Mao

    2015-09-01

    Approximately 400000t of DDTs/HCHs-contaminated soil (CS) needed to be co-processed in a cement kiln with a time limitation of 2y. A new pre-processing facility with a "drying, grinding and DDTs/HCHs vaporizing" ability was equipped to meet the technical requirements for processing cement raw meal and the environmental standards for stack emissions. And the bottom of the precalciner with high temperatures >1000°C was chosen as the CS feeding point for co-processing, which has rarely been reported. To assess the environmental performance of CS pre- and co-processing technologies, according to the local regulation, a test burn was performed by independent and accredited institutes systematically for determination of the clinker quality, kiln stack gas emissions and destruction efficiency of the pollutant. The results demonstrated that the clinker was of high quality and not adversely affected by CS co-processing. Stack emissions were all below the limits set by Chinese standards. Particularly, PCDD/PCDF emissions ranged from 0.0023 to 0.0085ngI-TEQNm(-3). The less toxic OCDD was the peak congener for CS co-processing procedure, while the most toxic congeners (i.e. 2,3,7,8-TeCDD, 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDD) remained in a minor proportion. Destruction and removal efficiency (DRE) and destruction efficiency (DE) of the kiln system were better than 99.9999% and 99.99%, respectively, at the highest CS feeding rate during normal production. To guarantee the environmental performance of the system the quarterly stack gas emission was also monitored during the whole period. And all of the results can meet the national standards requirements. PMID:25966458

  13. Use of treated wastewater in agriculture: effects on soil environment

    Science.gov (United States)

    Levy, Guy J.; Lado, Marcos

    2014-05-01

    Disposal of treated sewage, both from industrial and domestic origin (herein referred to as treated wastewater [TWW]), is often considered as an environmental hazard. However, in areas afflicted by water scarcity, especially in semi-arid and arid regions, where the future of irrigated agriculture (which produces approximately one third of crop yield and half the return from global crop production) is threatened by existing or expected shortage of fresh water, the use of TWW offers a highly effective and sustainable strategy to exploit a water resource. However, application of TWW to the soil is not free of risks both to organisms (e.g., crops, microbiota) and to the soil. Potential risks may include reduction in biological activity (including crop yield) due to elevated salinity and specific ion toxicity, migration of pollutants towards surface- and ground-water, and deterioration of soil structure. In recent years, new evidence about the possible negative impact of long-term irrigation with TWW on soil structure and physical and chemo-physical properties has emerged, thus putting the sustainability of irrigation with TWW in question. In this presentation, some aspects of the effects of long-term irrigation with TWW on soil properties are shown.

  14. Refracture of osteoporotic vertebral body concurrent with cement fragmentation at the previously treated vertebral level after balloon kyphoplasty: a case report.

    Science.gov (United States)

    Li, Xigong; Lou, Xianfeng; Lin, Xiangjin; Du, Junhua

    2014-05-01

    Kyphoplasty has been shown to provide symptomatic relief of vertebral compression fractures refractory to medical therapy. However, few reports have focused on refracture of cemented vertebrae after kyphoplasty. The presence of cemented vertebrae refracture concurrent with cement fragmentation is an extremely rare condition. We reported an 86-year-old man with a T12 osteoporotic compression fracture undergoing the kyphoplasty treatment. The patient postoperatively continued to have back pain at the same level. The solid lumped polymethylmethacrylate (PMMA) mass and inadequate use and insufficient filling of PMMA cement were observed in postoperative radiographs and magnetic resonance image (MRI) examination. He refused to receive the surgical intervention, but had not strict compliance with oral anti-osteoporotic medications. Ten months postoperatively, refracture of osteoporotic vertebral body concurrent with cement fragmentation occurred at the previously kyphoplasty-treated vertebral level. Bone mineral analysis showed severe osteoporosis with a T-score of -4.0. The patient finally obtained therapeutic benefit of pain relief and bony union of T12 vertebral body by consistently adhering to anti-osteoporotic medication treatment. This case illustrated that patients who underwent kyphoplasty to treat osteoporotic vertebral compression fractures with intravertebral fracture should be strictly followed up and supervised in their anti-osteoporotic medication treatment. The interdigitation injection pattern of PMMA and sufficient PMMA filling with trabeculae in the kyphoplasty procedure also might prevent refracture of the cemented vertebrae concurrent with PMMA fragmentation.

  15. Microbial communities in microcosm soils treated with battery waste

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Battery waste is one of the most destructive hazards to our environment, especially to the soil. In order to understand the effects of the battery waste on the microbial communities in soil, microcosm soils were treated with the powder made from the battery waste. Microbial biomass and respiration were measured after 15, 30, 45, and 60 days of the treatment, and catabolic capability and Biolog profile were determined after 60 days. Microbial biomass was declined by all treatments, while microbial respiration and catabolic capability were enhanced. Although microbial biomass recovered after a period of incubation, microbial respiratory quotient, catabolic capability and community structure remained significantly affected. Our results also suggest that microbial respiratory quotient and Biolog parameters are more sensitive than microbial biomass to the battery stress on bioavailability.

  16. Geotechnical properties of peat soil stabilised with shredded waste tyre chips in combination with gypsum, lime or cement

    Directory of Open Access Journals (Sweden)

    M. Saberian

    2016-07-01

    Full Text Available Peat has a high content of water and organic substances. These weak components can cause low bearing capacity and high consolidation settlement under load, which means that peat deposits must usually be stabilised if they are to bear constructions such as buildings or roads. In this study we investigated the performance of waste tyre chips (10 % by weight and sand (400 kg m-3 supplemented with a pozzolanic binder (gypsum, lime or cement at a range of dosages (5 %, 10 % or 15 % by weight as a stabiliser for peat soil. Peat samples were taken from a fen peatland at Chaghakhor Wetland in Chahar Mahal and Bakhtiari Province, Iran. In total, 162 test specimens were prepared and subjected to laboratory strength testing (unconfined compression test and direct shear test. Additionally, the pH of each admixture was recorded immediately after mixing, elemental compositions were determined by X-Ray Fluorescence (XRF, and structures were examined using Scanning Electron Microscopy (SEM. It was observed that: (1 the total percentage of pozzolanic compounds in the peat soil was well below the minimum of 70 % set by the standard ASTM C 618 (ASTM 2000, so an additive such as cement, lime or gypsum would certainly be required; (2 specimens stabilised with gypsum or lime showed improvements in unconfined compressive strength (UCS, but those stabilised with ordinary Portland cement exhibited the greatest improvement in UCS (up to 12,200 % as well as improvements in the direct shear parameters c and φ; (3 according to the XRF tests, additives such as cement, lime and gypsum introduced considerable amounts of Si, Al, Ca and O, which are important for pozzolanic reactions in peat soils; and (4 on the basis of the results of UCS and direct shear tests, the optimum percentage of the additives tested would be 5 %.

  17. Microtensile strength of resin cement bond to indirect composite treated by different output powers of Er:YAG laser.

    Science.gov (United States)

    Garshasbzadeh, Nazanin Zeinab; Mirzaie, Mansoreh; Yassini, Esmaeil; Shahabi, Sima; Benedicenti, Stefano; Angiero, Francesca; Chiniforush, Nasim

    2016-04-01

    The study aimed to evaluate the effect of different output powers of Er:YAG laser on microtensile bonding strength of indirect composite to resin cements.36 indirect composite blocks (GC Gradia DA2, Japan) size 15 × 10 × 10 mm(3) were constructed, and divided into 12 groups, as follows:G1: control group (no treatment); Groups G2 to G6: treated with Er:YAG laser (2,940 nm) in noncontact mode, frequency 20 Hz, pulse duration 470 µs, with output power ranging from 2W to 6W; Groups G7 sandblasting, Groups 8 to G12: as Groups G2 to G 6 with preparatory sandblasting. One specimen from each group was analyzed by SEM; each specimen was fixed to a specialized metal jig using cyanoacrylate (Mitreapel, Beta Kimya San. Ve TIC, Iran) and debonded under tension with a universal testing machine (Zwick, Germany) at a crosshead speed of 0.5 mm min(-1). Sandblasting and laser can improve bond strength above an energy level of 150 mJ. SEM evaluation of laser-treated specimens showed irregularities and deep undercuts. T test analysis showed no significant difference between sandblasted and non-sandblasted group, with laser output power of 0, 100, or 150 mJ (P = 0.666, P = 0.875, and P =  .069); in the specimens irradiated with energy output of 200, 250, or 300 mJ, sandblasted specimens showed higher bond strength than non-sandblasted ones. The results demonstrate that, in composite resin irradiated with laser at energy output of 200-300 mJ, sandblasting might be a suitable procedure to enhance bond strength of resin cement. PMID:26873266

  18. ALTERNATIVE FIELD METHODS TO TREAT MERCURY IN SOIL

    Energy Technology Data Exchange (ETDEWEB)

    Ernie F. Stine

    2002-08-14

    The Department of Energy (DOE) currently has mercury (Hg) contaminated materials and soils at the various sites. Figure 1-1 (from http://www.ct.ornl.gov/stcg.hg/) shows the estimated distribution of mercury contaminated waste at the various DOE sites. Oak Ridge and Idaho sites have the largest deposits of contaminated materials. The majorities of these contaminated materials are soils, sludges, debris, and waste waters. This project concerns treatment of mercury contaminated soils. The technology is applicable to many DOE sites, in-particular, the Y-12 National Security Complex in Oak Ridge Tennessee and Idaho National Engineering and Environmental Laboratory (INEEL). These sites have the majority of the soils and sediments contaminated with mercury. The soils may also be contaminated with other hazardous metals and radionuclides. At the Y12 plant, the baseline treatment method for mercury contaminated soil is low temperature thermal desorption (LTTD), followed by on-site landfill disposal. LTTD is relatively expensive (estimated cost of treatment which exclude disposal cost for the collect mercury is greater than $740/per cubic yard [cy] at Y-12), does not treat any of the metal or radionuclides. DOE is seeking a less costly alternative to the baseline technology. As described in the solicitation (DE-RA-01NT41030), this project initially focused on evaluating cost-effective in-situ alternatives to stabilize or remove the mercury (Hg) contamination from high-clay content soil. It was believed that ex-situ treatment of soil contaminated with significant quantities of free-liquid mercury might pose challenges during excavation and handling. Such challenges may include controlling potential mercury vapors and containing liquid mercury beads. As described below, the focus of this project was expanded to include consideration of ex-situ treatment after award of the contract to International Technology Corporation (IT). After award of the contract, IT became part of Shaw

  19. ALTERNATIVE FIELD METHODS TO TREAT MERCURY IN SOIL

    International Nuclear Information System (INIS)

    The Department of Energy (DOE) currently has mercury (Hg) contaminated materials and soils at the various sites. Figure 1-1 (from http://www.ct.ornl.gov/stcg.hg/) shows the estimated distribution of mercury contaminated waste at the various DOE sites. Oak Ridge and Idaho sites have the largest deposits of contaminated materials. The majorities of these contaminated materials are soils, sludges, debris, and waste waters. This project concerns treatment of mercury contaminated soils. The technology is applicable to many DOE sites, in-particular, the Y-12 National Security Complex in Oak Ridge Tennessee and Idaho National Engineering and Environmental Laboratory (INEEL). These sites have the majority of the soils and sediments contaminated with mercury. The soils may also be contaminated with other hazardous metals and radionuclides. At the Y12 plant, the baseline treatment method for mercury contaminated soil is low temperature thermal desorption (LTTD), followed by on-site landfill disposal. LTTD is relatively expensive (estimated cost of treatment which exclude disposal cost for the collect mercury is greater than $740/per cubic yard [cy] at Y-12), does not treat any of the metal or radionuclides. DOE is seeking a less costly alternative to the baseline technology. As described in the solicitation (DE-RA-01NT41030), this project initially focused on evaluating cost-effective in-situ alternatives to stabilize or remove the mercury (Hg) contamination from high-clay content soil. It was believed that ex-situ treatment of soil contaminated with significant quantities of free-liquid mercury might pose challenges during excavation and handling. Such challenges may include controlling potential mercury vapors and containing liquid mercury beads. As described below, the focus of this project was expanded to include consideration of ex-situ treatment after award of the contract to International Technology Corporation (IT). After award of the contract, IT became part of Shaw

  20. Proximal Tibia Chondroblastoma Treated With Curettage and Bone Graft and Cement Use.

    Science.gov (United States)

    Cho, Hwan Seong; Park, Yeong Kyoon; Oh, Joo Han; Lee, Jung Hyun; Han, Ilkyu; Kim, Han-Soo

    2016-01-01

    Chondroblastoma has a predilection for the epiphyses or apophyses of long tubular bones. Management of lesions in the proximal tibia is challenging because it is difficult to gain access to intraepiphyseal lesions for completion of curettage. From October 2007 to December 2011, 9 patients with de novo chondroblastoma of the proximal tibia underwent surgery at the authors' institution. All patients initially presented with pain, and 5 patients had limitation of range of motion of the ipsilateral knee. Four lesions abutted the tibial attachment sites of the cruciate ligaments. Surgical procedures included intralesional tumor curettage, additional burring, and packing of the defect with bone graft and/or bone cement. The extra-articular approach was used according to tumor location. The medial or lateral parapatellar approach was used when the tumor was located in the anterior two-thirds of the horizontal plane. When a lesion was located in the posterior third, the posteromedial or posterolateral approach was used as the lesion was cornered. Mean duration of follow-up was 47.2 months (range, 27-80 months). No local recurrence or pulmonary metastasis was noted at latest follow-up. Mean functional score was 29.3 points (range, 28-30 points). All patients fully recovered range of motion in the affected knee. No avulsion fracture or anteroposterior instability of the knee joint was detected. Results of the current study suggest that intralesion curettage followed by additional burring with an extra-articular approach is a successful treatment option for chondroblastoma of the proximal tibia.

  1. Proximal Tibia Chondroblastoma Treated With Curettage and Bone Graft and Cement Use.

    Science.gov (United States)

    Cho, Hwan Seong; Park, Yeong Kyoon; Oh, Joo Han; Lee, Jung Hyun; Han, Ilkyu; Kim, Han-Soo

    2016-01-01

    Chondroblastoma has a predilection for the epiphyses or apophyses of long tubular bones. Management of lesions in the proximal tibia is challenging because it is difficult to gain access to intraepiphyseal lesions for completion of curettage. From October 2007 to December 2011, 9 patients with de novo chondroblastoma of the proximal tibia underwent surgery at the authors' institution. All patients initially presented with pain, and 5 patients had limitation of range of motion of the ipsilateral knee. Four lesions abutted the tibial attachment sites of the cruciate ligaments. Surgical procedures included intralesional tumor curettage, additional burring, and packing of the defect with bone graft and/or bone cement. The extra-articular approach was used according to tumor location. The medial or lateral parapatellar approach was used when the tumor was located in the anterior two-thirds of the horizontal plane. When a lesion was located in the posterior third, the posteromedial or posterolateral approach was used as the lesion was cornered. Mean duration of follow-up was 47.2 months (range, 27-80 months). No local recurrence or pulmonary metastasis was noted at latest follow-up. Mean functional score was 29.3 points (range, 28-30 points). All patients fully recovered range of motion in the affected knee. No avulsion fracture or anteroposterior instability of the knee joint was detected. Results of the current study suggest that intralesion curettage followed by additional burring with an extra-articular approach is a successful treatment option for chondroblastoma of the proximal tibia. PMID:26726978

  2. 碳酸钠对水泥土强度的影响%The influence of NaCO3 on the strength of cemented-soil

    Institute of Scientific and Technical Information of China (English)

    贾尚华; 申向东; 周丽萍; 张鹏远; 温永钦

    2011-01-01

    In the other conditions constant,the relationship between the sadium carhonate mixing ratio and strength of cemented soil was studied. Through comparing cemented soil's strengths of 7 days and 28 days,it has been presented that with the increasing of sodium carbonate mixing ratio,the cemented soil's strengths first increased and then decreased and that the peak strength of cemented soil move forward with age increase. The main reasons are that sodium carbonate promotes the hydration and inhibits conversion of hydrated precipitation from hydrated gel and that sodium carbonate inhibits the pozzolanic reaction and the others which increase the strength of cemented soil heavily in later stage.%在其它条件恒定时,研究了碳酸钠掺量对水泥土强度的影响.对比水泥土7d和28 d的强度发现,水泥土的强度总体上随碳酸钠掺量的增加先增大后减小;随龄期增长,水泥土强度峰值前移.分析原因主要为:碳酸钠促进水化作用和抑制硅酸凝胶转化为沉淀的双重功能,碳酸钠抑制了对水泥土后期强度增长有重要作用的火山灰效应等.

  3. Cola à base de PVA e argamassa de solo-cimento como alternativas para o assentamento de alvenaria de tijolos maciços de solo-cimento PVA glue and cement soil mortars as alternatives for laying cement soil blocks masonry

    Directory of Open Access Journals (Sweden)

    Gisleiva C. dos S. Ferreira

    2011-04-01

    Full Text Available Neste trabalho, foi analisada a viabilidade de emprego de cola à base de PVA e argamassa de solo-cimento no assentamento de paredes de alvenaria de tijolos maciços de solo-cimento, em substituição à argamassa usual (cimento, cal e areia. Pequenos prismas, executados com quatro tijolos maciços de solo-cimento e assentados com as argamassas e a cola de PVA, foram ensaiados à compressão e à flexão. Os resultados dos ensaios dos prismas executados com a argamassa de assentamento usual foram tomados como padrão esperado de comportamento para os outros prismas executados com argamassa de solo-cimento e com cola de PVA. Os resultados obtidos nos ensaios dos prismas indicaram que tanto cola à base de PVA quanto argamassa de solo-cimento podem ser empregadas, satisfatoriamente, no assentamento de painéis de alvenaria de tijolos maciços de solo-cimento.This study presents the results of an experimental investigation in characterizing the properties of cement soil block masonry using cement-soil mortars and PVA glue. The study deals with the scantily explored area of tensile bond strength of soil-cement block masonry using cement-soil mortars and PVA glue. Flexural bond strength of masonry has been determined by testing stack-bonded prisms using a bond wrench test set-up. The study clearly demonstrates the superiority of cement-soil mortar over other conventional mortar such as cement mortar. The results of this study can be conveniently used to select a proportion for cement-soil mortar or PVA glue proportion for cement soil block masonry structures.

  4. Bond strength of resin cement to dentin and to surface-treated posts of titanium alloy, glass fiber, and zirconia

    DEFF Research Database (Denmark)

    Sahafi, Alireza; Peutzfeldt, Anne; Asmussen, Erik;

    2003-01-01

    PURPOSE: To determine the effect of surface treatments on bond strength of two resin cements (ParaPost Cement and Panavia F) to posts of titanium alloy (ParaPost XH), glass fiber (ParaPost Fiber White), and zirconia (Cerapost), and to dentin. MATERIALS AND METHODS: After embedding, planar surface...

  5. 分层土中水泥土围护结构抗倾覆验算方法的改进%Improved method for calculating anti-overturning safety factor of cement-soil retaining wall in layered soil

    Institute of Scientific and Technical Information of China (English)

    李卫超; 熊巨华; 杨敏

    2011-01-01

    An improved anti-overturning safety factor calculation method of the cement-soil retaining wall in layered soil is presented Based on the improved method, the influence of different soil structures on the anti-overturning safety factor is analyzed. When the soft soil is over the hard soil the anti-overturning safety factor increases with increasing of the width and the embedded depth of the wall respectively. Similarly the anti-overturning safety factor also increases with increasing of the width of the wall but has less change with increasing of the embedded depth of the wall when the hard soil is over the soft soil. The reason for that is the anti-overturning safety of the cement-soil retaining wall relies mainly on the passive earth pressure; that is to say, the anti-overturning safety factor is influenced by the lower soil's strength mainly. If treating the layered soil parameters according to the thickness weighted as the homogeneous soil, the anti-overturning safety factor is smaller which inclines to conservative when the soft soil is over the hard soil. Unlike that the anti-overturning safety factor is bigger which has the security risk when the hard soil is over the soft soil. Compared with the conventional calculation method, the improved method presents a more reasonable and safe result%推导了分层土中水泥土围护结构抗倾覆稳定系数计算公式,提出了改进的计算方法,研究了土层分层结构对水泥土围护结构抗倾覆稳定系数的影响.土层上软下硬时,水泥土围护结构抗倾覆稳定系数分别随着墙体宽度与入土深度的增加而增加.土层上硬下软时,增加墙体宽度对于提高抗倾覆稳定系数具有较好的效果,而增加墙体入土深度对于提高抗倾覆稳定系数作用不大,因为分层土中,水泥土围护结构抗倾覆稳定性主要依靠下部土体的被动土压力来维持,即抗倾覆稳定性主要受下层土体强度的影响.如将分层土参数按厚度

  6. Re-use of stabilised flue gas ashes from solid waste incineration in cement-treated base layers for pavements.

    Science.gov (United States)

    Cai, Zuansi; Jensen, Dorthe L; Christensen, Thomas H; Bager, Dirch H

    2003-02-01

    Fly ash from coal-burning power plants has been used extensively as a pozzolan and fine filler in concrete for many years. Laboratory experiments were performed investigating the effect of substituting the coal-based fly ash with chemically stabilised flue gas ashes (FGA) from waste incineration. Two types of FGA were treated by the Ferrox-process, which removes the majority of the easily soluble salts in the FGA and provides binding sites for heavy metals in terms of ferrihydrite. Cubes of cement treated base layer materials containing 5% stabilised FGA were cast, sealed and cured for two weeks. Cylinders (diameter 100 mm, length 150 mm) were drilled from these cubes for tank leaching experiments. Duplicate specimens were subject to compression strength testing and to tank leaching experiments. The compressive strength of the CTB fulfilled the Danish requirements for CTB, i.e. strength more than 5 MPa after 7 days. The tank leaching tests revealed that leaching of heavy metals was not significantly affected by the use of chemically stabilised flue gas ashes from waste incineration. Assuming that diffusion controls the leaching process it was calculated that less than 1% of the metals would leach during a 100-year period from a 0.5 m thick concrete slab exposed to water on one side. Leaching of the common ions Ca, Cl, Na and SO4 was increased 3-20 times from the specimens with chemically stabilised flue gas ashes from waste incineration. However, the quantities leached were still modest. These experiments suggest that FGA from waste incineration after Ferrox-treatment could be re-used in CTB without compromising the strength and leaching from the base layer.

  7. Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

    Directory of Open Access Journals (Sweden)

    Schacht Karsten

    2015-03-01

    Full Text Available The use of treated wastewater (TWW for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC and soil aggregate stability (SAS. To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm were collected for analyzing SAS and determination of selected soil chemical and physical characteristics.

  8. Soil quality in a cropland soil treated with wood ash containing charcoal

    Science.gov (United States)

    Omil, Beatriz; Balboa, Miguel A.; Fonturbel, M. Teresa; Gartzia-Bengoetxea, Nahia; Arias-González, Ander; Vega, Jose A.; Merino, Agustin

    2014-05-01

    The strategy of the European Union "Europe 2020" states that by 2020, 20% of final energy consumption must come from renewables. In this scenario, there is an increasing use of biomass utilization for energy production. Indeed, it is expected that the production of wood-ash will increase in coming years. Wood ash, a mixture of ash and charcoal, generated as a by-product of biomass combustion in power plants, can be applied to soil to improve the soil quality and crop production. Since the residue contains significant content of charcoal, the application of mixed wood ash may also improve the SOM content and soil quality in the long term, in soils degraded as a consequence of intensive management. The objective of this study was asses the changes in SOM quality and soil properties in a degraded soils treated with wood ash containing charcoal. The study was carried out in a field devoted to cereal crops during the last decades. The soil was acidic (pH 4.5) with a low SOC content (3 %) and fine texture. The experiment was based on a randomised block design with four replicates. Each block included the following four treatments: Control, 16 Mg fly wood ash ha-1, 16 Mg mixed wood ash ha-1 (16 Mg) and 32 Mg mixed wood ash ha-1 (32 Mg). The application was carried out once. The ash used in the study was obtained from a thermal power plant and was mainly derived from the combustion of Pinus radiata bark and branches. The wood ash is highly alkaline (pH= 10), contains 10 % of highly condensed black carbon (atomic H/C ratio Differential Scanning Calorimetry (DSC). These techniques were applied in bulk samples and aggregates of different sizes. The changes in microbial activity were studied by analysis of microbial biomass C and basal respiration. The soil bacterial community was studied by the Biolog method. Several physical properties, such soil aggregate distribution, hydraulic conductivity and available water contente were also determined. Three years after applications

  9. Soil-Water Characteristic Curves of Red Clay treated by Ionic Soil Stabilizer

    Science.gov (United States)

    Cui, D.; Xiang, W.

    2009-12-01

    The relationship of red clay particle with water is an important factor to produce geological disaster and environmental damage. In order to reduce the role of adsorbed water of red clay in WuHan, Ionic Soil Stabilizer (ISS) was used to treat the red clay. Soil Moisture Equipment made in U.S.A was used to measure soil-water characteristic curve of red clay both in natural and stabilized conditions in the suction range of 0-500kPa. The SWCC results were used to interpret the red clay behavior due to stabilizer treatment. In addition, relationship were compared between the basic soil and stabilizer properties such as water content, dry density, liquid limit, plastic limit, moisture absorption rate and stabilizer dosages. The analysis showed that the particle density and specific surface area increase, the dehydration rate slows and the thickness of water film thins after treatment with Ionic Soil Stabilizer. After treatment with the ISS, the geological disasters caused by the adsorbed water of red clay can be effectively inhibited.

  10. The Adsorption and Desorption of Pb(2+) and Cd(2+) in Freeze-Thaw Treated Soils.

    Science.gov (United States)

    Li, Linhui; Ma, Jincai; Xu, Meng; Li, Xu; Tao, Jiahui; Wang, Guanzhu; Yu, Jitong; Guo, Ping

    2016-01-01

    Adsorption and desorption are important processes that influence the potential toxicity and bioavailability of heavy metals in soils. However, information regarding adsorption and desorption behavior of heavy metals in soils subjected to freeze-thaw cycles is poorly understood. In the current study, the effect of freeze-thaw cycles with different freezing temperature (-15, -25, -35°C) on soil properties was investigated. Then the adsorption and desorption behavior of Pb(2+) and Cd(2+) in freeze-thaw treated soils was studied. The adsorption amounts of Pb(2+) and Cd(2+) in freeze-thaw treated soils were smaller than those in unfrozen soils (p adsorption amounts of Pb(2+) and Cd(2+) in soils treated with lower freezing temperatures were higher than those in soils treated with higher freezing temperatures. Desorption percentages of Pb(2+) and Cd(2+) in unfrozen soils were smaller than those in freeze-thaw treated soils (p adsorption and desorption behavior of typical heavy metals in freeze-thaw treated soils located in seasonal frozen soils zone in northeast China.

  11. 闭孔珍珠岩对水泥土力学性能影响%Effect of Obturation Perlite on Mechanical Properties of Cement-Soil

    Institute of Scientific and Technical Information of China (English)

    侯宇慧; 申向东

    2012-01-01

    通过室内向水泥土中掺入闭孔珍珠岩的无侧限抗压强度试验,研究了不同掺量、不同龄期对水泥土无侧限抗压强度的影响,分析了单轴受压下的应力-应变曲线及作用机理.研究结果表明:掺入适量的闭孔珍珠岩可以有效地增强水泥土强度,改善其力学性能.%Through unconfined compressive strength test of soil-obturation perlite-cement in laboratory, It is studied that different amount of obturation perlite in cement-soil and different curing age have influences on unconfined compressive strength of cement-soil and it is analyzed that the changes of stress-strain curve by stressing on single shaft and action principle. The results of the study show that the right a-mount of obturation perlite can effectively reinforce cement-soil and improve its mechanical properties.

  12. Biodegradability of pharmaceutical compounds in agricultural soils irrigated with treated wastewater

    International Nuclear Information System (INIS)

    Pharmaceutical compounds (PCs) are introduced into agricultural soils via irrigation with treated wastewater (TWW). Our data show that carbamazepine, lamotrigine, caffeine, metoprolol, sulfamethoxazole and sildenafil are persistent in soils when introduced via TWW. However, other PCs, namely diclofenac, ibuprofen, bezafibrate, gemfibrozil and naproxen were not detected in soils when introduced via TWW. This is likely due to rapid degradation as confirmed in our microcosm studies where they exhibited half-lives (t1/2) between 0.2–9.5 days when soils were spiked at 50 ng/g soil and between 3 and 68 days when soils were spiked at 5000 ng/g soil. The degradation rate and extent of PCs observed in microcosm studies were similar in soils that had been previously irrigated with TWW or fresh water. This suggests that pre-exposure of the soils to PCs via irrigation with TWW does not enhance their biodegradation. This suggests that PCs are probably degraded in soils via co-metabolism. Highlights: • Some pharmaceuticals are highly persistent in arable soils. • Weak acid pharmaceuticals are readily degradable in agricultural soils. • Irrigation with treated wastewater does not enhance degradation of pharmaceuticals. • Degradation of pharmaceuticals in soil is probably occurred via co-metabolism. -- Some pharmaceutical compounds are persistent in arable soils when introduced via irrigation with treated wastewater

  13. Germination of Blue Wildrye in Biochar Treated Mining Impacted Soils

    Science.gov (United States)

    Stabilization of mine sites with vegetation is an important management strategy to reduce metal movement off-site. Plant growth, however, is often hampered by poor soil conditions. Biochar is a novel soil amendment that may improve soil health conditions and improve plant growt...

  14. 钉形水泥土双向搅拌桩加固软土地基的效果分析%Analysis of effect of T-shaped bidirectional soil-cement deep mixing columns reinforcing soil foundation

    Institute of Scientific and Technical Information of China (English)

    朱志铎; 刘松玉; 席培胜; 周礼红

    2009-01-01

    针对水泥土搅拌桩应用中存在的问题,介绍了最新研制的钉形水泥土双向搅拌桩及其施工工艺.施工质量检验表明,钉形水泥土双向搅拌桩桩体质量好于常规水泥土搅拌桩,钉形水泥土双向搅拌桩单桩及复合地基承载力分别较常规水泥土搅拌桩的单桩及复合地基承载力有较大提高.通过对试验段的观测成果分析,论证了钉形水泥土双向搅拌桩加固软土地基优越的工程特性.%In light of the existing problems in the development of soil-cement mixing piles, T-shaped bidirectional soil-cement deep mixing columns and their construction technology are introduced. Construction quality test results show that the quality of T-shaped bidirectional soil-cement deep mixing columns are better than conventional soil-cement mixing piles. Compared to conventional cement mixing piles composite foundation, the bearing capacity of the pile foundation and composite have improved greatly. Through the observation of the analysis of test site result, the engineering properties and economic benefits of the method that T-shaped bidirectional soil-cement deep mixing columns reinforces soft ground superior are demonstrated.

  15. 玻璃纤维粉煤灰水泥土的力学特性%Mechanical Behavior of Glass Fiber and Fly Ash Soil-cement

    Institute of Scientific and Technical Information of China (English)

    赫文秀; 申向东

    2012-01-01

    将工业生产的废料粉煤灰和价格相对低廉的玻璃纤维应用到水泥土中,运用正交试验方法,通过室内无侧限抗压强度试验,研究了玻璃纤维粉煤灰水泥土的无侧限抗压强度的影响因素及其发展规律.试验研究表明:在水泥土中掺入一定量的粉煤灰和玻璃纤维可以明显地提高水泥土的无侧限抗压强度.通过正交试验各个因素分析可得:龄期和水泥掺量对水泥土强度的影响较大,其次是粉煤灰,而玻璃纤维对强度的影响较小;同时对水泥、粉煤灰、玻璃纤维3个因素对玻璃纤维粉煤灰水泥土强度增长机理进行分析得到:水泥的水化是玻璃纤维粉煤灰水泥土强度增长的主要来源;粉煤灰的作用主要体现在填充效应、水化效应和形态效应3个方面;玻璃纤维的主要作用为固结加筋.%Industrial waste fly ash and relatively economical fiber glass were applied to soil-cement. By using orthogonal test method and through laboratory unconfined compressive strength test, the influencing factors and the development regularity of unconfined compressive strength of glass fiber and fly ash cement soil were discussed. The test result shows that with a certain amount of fly ash and glass fiber in soil-cement can significantly improve the unconfined compressive strength of soil-cement. Through the analysis of different factors in the orthogonal test, it shows that age and content of cement have significant impact on compressive strength of soil-cement, then is fly ash, and the impact of glass fiber is less. Through the analysis of the influence of cement, fly ash and glass fiber on the increment mechanism of strength of glass fiber fly ash cement-soil, it shows the hydration of cement mainly caused strength increment of glass fiber fly ash cement-soil, while the fly ash mainly acted for filling, hydration and morphology; and the main role of glass fiber was reinforced consolidation.

  16. Cement Mason's Curriculum. Instructional Units.

    Science.gov (United States)

    Hendirx, Laborn J.; Patton, Bob

    To assist cement mason instructors in providing comprehensive instruction to their students, this curriculum guide treats both the skills and information necessary for cement masons in commercial and industrial construction. Ten sections are included, as follow: related information, covering orientation, safety, the history of cement, and applying…

  17. Impact of cement dust pollution on Cedrela fissilis Vell. (Meliaceae): A potential bioindicator species.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Lemos-Filho, José Pires; Paiva, Elder Antonio Sousa

    2016-09-01

    Considering the impacts caused to vegetation in the vicinity of cement factories, the aim of this study was to evaluate the impacts of cement dust on the structural organization and physiological/biochemical traits of Cedrela fissilis leaflets, a woody species native to tropical America. Plants were exposed to 2.5 or 5 mg cm-2 cement dust applied to the leaf surface, to the soil or simultaneously to the leaf surface and the soil.. Leaves of shoot-treated plants exhibited chlorosis, marginal and inter veins necrosis, diminished thickness, epidermal cells less turgid, cellular collapse, obstructed stomata, senescence, rolling and some abscission. In few cases, individual death was recorded. Cement dust-treated plants also presented decreased amount of photosynthetic pigments and iron (Fe) and increase in calcium (Ca) levels. The cement crust formed in leaves surface blocked from 30 to 50% of the incoming light and reduced the stomatal conductance and the potential quantum yield of photosystem II. Control or soil-treated plants did not exhibit morphophysiological changes throughout the experiment. The activity of superoxide dismutase, catalase and ascorbate peroxidase increased in leaves of plants upon treatment with 2.5 mg cm(-2) cement dust, independent of the site application. Overall, these results indicate that C. fissilis is highly sensitive to cement dust at the initial stage of development.

  18. Impact of cement dust pollution on Cedrela fissilis Vell. (Meliaceae): A potential bioindicator species.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Lemos-Filho, José Pires; Paiva, Elder Antonio Sousa

    2016-09-01

    Considering the impacts caused to vegetation in the vicinity of cement factories, the aim of this study was to evaluate the impacts of cement dust on the structural organization and physiological/biochemical traits of Cedrela fissilis leaflets, a woody species native to tropical America. Plants were exposed to 2.5 or 5 mg cm-2 cement dust applied to the leaf surface, to the soil or simultaneously to the leaf surface and the soil.. Leaves of shoot-treated plants exhibited chlorosis, marginal and inter veins necrosis, diminished thickness, epidermal cells less turgid, cellular collapse, obstructed stomata, senescence, rolling and some abscission. In few cases, individual death was recorded. Cement dust-treated plants also presented decreased amount of photosynthetic pigments and iron (Fe) and increase in calcium (Ca) levels. The cement crust formed in leaves surface blocked from 30 to 50% of the incoming light and reduced the stomatal conductance and the potential quantum yield of photosystem II. Control or soil-treated plants did not exhibit morphophysiological changes throughout the experiment. The activity of superoxide dismutase, catalase and ascorbate peroxidase increased in leaves of plants upon treatment with 2.5 mg cm(-2) cement dust, independent of the site application. Overall, these results indicate that C. fissilis is highly sensitive to cement dust at the initial stage of development. PMID:27243585

  19. Chesterton soil concretions: ilmenite and not iron-manganese cementing matrix.

    Science.gov (United States)

    White, K L

    1979-06-01

    Dark reddish-brown spherules are common in soils of the Chesterton soil series of a high marine terrace in southern California. The spherules are concretionary in structure and are bound by ilmenite rather than by an iron-manganese complex. The spherules have been mislabeled both with respect to structure and mineralogy.

  20. Strength Development of Lime Treated Artificial Organic Soil

    Science.gov (United States)

    Yeo, S. W.; Ling, F. N. L.; Sulaeman, A.; Low, V. S.; Toh, K. L.

    2016-07-01

    In over many years, considerable research has been carried out on organic soils which consists of various components of organic matter but the effect of particular organic matter is less reported. Thus, some of contributing factors for each organic matter are not fully understood yet. Hence, the aim of this study is to determine the effect of organic acid concentration on the strength of artificial organic soil. There are four types of artificial organic soil created by mixing kaolin (inorganic matter) and organic acid (a kind of humified organic matter) in different concentrations. Unconfined Compressive Strength test (UCT) was carried out for all soil samples after being cured for 7 and 28 days under room temperature and 50°C. Soil samples shows highest strength when cured for 28 days under 50°C compared to those cured under room temperature. However, when the organic acid concentration decrease, the strength increased for soil 2 after 7 and 28 days cured under room temperature and 50°C. Apart from this, soil 3 and soil 4 that were cured under room temperature shows decrease in strength when the organic acid concentration decreasing but different result shown for both samples when cured under 50°C.

  1. Cement Conundrum

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China aims to streamline the crowded cement industry Policymakers are looking to build a concrete wall around the cement-making industry as they seek to solidify the fluid cement market and cut excessive production.

  2. Comparison of the resin cement bond strength to an indirect composites treated by Er;YAG laser and sandblast

    Directory of Open Access Journals (Sweden)

    Mansure Mirzaee

    2014-04-01

    Full Text Available   Background and Aims: Indirect composites are designed to overcome the shortcomings of direct composites such as polymerization shrinkage and low degree of conversion. But, good adhesion of resin cements to indirect composites is still difficult. This research was designed to assess the effect of different powers of Er;YAG laser compared with sandblasting. On the micro tensil bond strength of resin cement to indirect composites.   Materials and Methods: Specimens were prepred using dental resin composite (Gradia GC and metallic mold (15×5×5 mm and were cured according to the manufacturer’s instructions. 24 blocks were prepared and randomly divided into 12 groups. G1:no treatment (as control, G 2-6: Er; YAG laser irradiation (2, 3, 4, 5, 6 Watt, G7: sandblast. Two composite blocks were bonded to each other with Panavia F.2. resin cement. The cylindrical sections with dimensions of 1 mm were tested in a microtensile bond strength tester device using 0.5 mm/min speed until fracture points. Data were analyzed using 2-way ANOVA and T-test.   Results: Interaction between lasers irradiation and sandblast treatments were significant (P0.05 whether samples were sandblasted or not. Samples which received 300 mJ of laser showed lower bond strength compared with no laser treatment. Other groups showed no significant difference (P>0.05.   Conclusion: It seems that application of sandblast with proper variables, is a good way to improve bond strength.Laser application had no influence in improving the bond strength between the indirect composite and resin cement.

  3. PERFORNACE OF RECRON-3S FIBER WITH CEMENT KILN DUST IN EXPANSIVE SOILS

    Directory of Open Access Journals (Sweden)

    P.V.KOTESWARA RAO

    2012-04-01

    Full Text Available In the present work, an attempt is made to study the influence of polymer fibers on the properties of locally available Black cotton soil with and without admixture modification. This study revealedthat the fiber reinforcement improves the soil properties in terms of improved stress-strain patterns and progressive failure in place of quick post peak failure of plain samples. The unconfined compressive strength of Clay soil is increased by 7 times with admixture stabilization and 9 times for admixture with fiber modificationwith respect to plain samples. The shear strength parameters of clay soil are also significantly increased upon admixture stabilization and admixture with fiber treatment. The CBR value also increased significantly even for soaked CBR tests. By addition of CKD the Liquid limit of the mixture is decreased 23 %, where as plastic limitis increased by 41%. Plasticity Index of the mix is decreased by 57%.

  4. Unconfined compressive strength test of composite mineral powder soil-cement%复合矿粉水泥土的无侧限抗压强度试验

    Institute of Scientific and Technical Information of China (English)

    马晓宇; 李平

    2014-01-01

    将工业中生产的废渣制作成的复合矿粉掺加至水泥土中,既增强其性能,同时也可达到利废环保的目的。通过室内无侧限抗压强度试验,运用正交试验方法研究了影响复合矿粉水泥土抗压强度的主要因素及其影响规律。通过极差和方差分析可知,水泥掺量对复合矿粉水泥土的无侧限抗压强度的影响最大,其次是龄期,复合矿粉的影响最小。复合矿粉水泥土的早期强度提高主要是由于水泥的水化,而由矿粉和粉煤灰组成的复合矿粉具有微集料效应和火山灰效应,从而可改善水泥土的强度。%To mix the soil-cement with composite mineral powder made from the slag in industrial production can reinforce the property of the soil-cement,and is also environment-friendly to utilize the waste.Based on the indoor unconfined compressive strength test,we investigated the main factors that influence the compressive strength of composite mineral powder soil-cement. Analysis of range and variance shows that cement content is the major factor affecting the unconfined compressive strength,fol-lowed by age and in the last place,composite mineral powder.The improvement of strength of composite mineral powder soil-ce-ment in the early period is mainly due to hydration of cement,while composite mineral powder which is made of mineral powder and fly ash has micro aggregate effect and pozzolanic effect.In general,the strength of soil-cement could be fairly improved.

  5. Treating Soil Solution Samplers To Prevent Microbial Removal of Analytes

    OpenAIRE

    Lewis, David L.; Simons, Alex P.; Moore, W. Bruce; Gattie, David K

    1992-01-01

    Soil microorganisms colonizing soil water sampling devices (lysimeters) reduced concentrations of biodegradable organic chemicals, including 2,4-dichlorophenoxyacetic acid methyl ester, alachlor, methyl m-chlorobenzoate, and metolachlor as water entered through porous ceramic cups. In some cases, losses exceeded 99%. Additions of either a biocide (sodium hypochlorite) or a bacteriostat (copper salt) prevented microbial activity so that concentrations of test chemicals inside lysimeters equale...

  6. 偏高岭土对水泥改性海相软土力学性能的影响%Influence of metakaolin on mechanical properties of cement-modified marine soft soil

    Institute of Scientific and Technical Information of China (English)

    储诚富; 李小春; 邓永锋; 唐俊玮

    2013-01-01

    针对水泥土搅拌法处理连云港海相软土出现可溶盐对水泥土腐蚀而产生强度劣化问题,研究了掺入偏高岭土的水泥土抗腐蚀性能.试验结果表明:偏高岭土能促进水泥土的水化反应和火山灰反应,显著提高水泥土强度,并得到了水泥土的偏高岭土最佳掺入比.研究成果为水泥海相土力学性能改良理论及海相软土水泥土搅拌法加固设计提供依据.%According to the strength degradation problems caused by corrosion of cement-soil by soluble salts when the marine soft soil in Lianyungang area is improved by means of the cement-soil mixing method,the effect ofmetakaolin on the corrosion resistance of soil-cement is investigated.The results indicate that the metakaolin can increase hydration reaction and pozzolanic reaction of cement-soil to obviously improve is strength,and the best mixing ratio ofmetakaolin of cement-soil is obtained.The results provide a basis for the improvement of theory of mechanical properties of cement marine soil and the reinforcement design of marine soft soil by use of the cement-soil mixing method.

  7. Ammonia-Oxidizer Communities in an Agricultural Soil treated with Contrasting Nitrogen Sources.

    OpenAIRE

    Mussie Y. Habteselassie; Li eXu; Norton, Jeanette M.

    2013-01-01

    The community of ammonia-oxidizing prokaryotes was examined in an agricultural soil treated for 6 seasons with contrasting nitrogen (N) sources. Molecular tools based on the gene encoding ammonia monooxygenase were used to characterize the ammonia oxidizer communities and their abundance. Soil DNA was extracted from soils sampled from silage corn plots that received no additional N (control), dairy waste compost (DC), liquid dairy waste (LW), and ammonium sulfate (AS) treatments at approxima...

  8. Evaluation of compressive strength and water absorption of soil-cement bricks manufactured with addition of pet (polyethylene terephthalate wastes

    Directory of Open Access Journals (Sweden)

    João Alexandre Paschoalin Filho

    2016-04-01

    Full Text Available This paper presents the evaluation of compressive strength of soil-cement bricks obtained by the inclusion in their mixture of PET flakes through mineral water bottles grinding. The Polyethylene Terephthalate (PET has been characterized by its difficulty of disaggregation in nature, requiring a long period for this. On the other hand, with the increase in civil construction activities the demand for raw material also increases, causing considerable environmental impacts. In this context, the objective of this research is to propose a simple methodology, preventing its dumping and accumulation in irregular areas, and reducing the demand of raw materials by the civil construction industry. The results showed that compressive strengths obtained were lower than recommended by NBR 8491 (Associação Brasileira de Normas Técnicas [ABNT], 2012b at seven days of curing time. However, they may be used as an alternative solution in masonry works in order to not submit themselves to great loads or structural functions. The studied bricks also presented water absorption near to recommended values by NBR 8491 (ABNT, 2012b. Manufacturing costs were also determined for this brick, comparing it with the costs of other brick types. Each brick withdrew from circulation approximately 300 g of PET waste. Thus, for an area of 1 m2 the studied bricks can promote the withdrawal of approximately 180 beverage bottles of 2 L capacity.

  9. In vitro gastrointestinal bioavailability of arsenic in soils collected near CCA-treated utility poles.

    Science.gov (United States)

    Pouschat, Priscilla; Zagury, Gerald J

    2006-07-01

    Because of the potentially high arsenic concentrations found in soils immediately adjacent to chromated copper arsenate (CCA)-treated wood structures and utility poles, CCA-contaminated soil ingestion may be a significant exposure route to arsenic for children. Therefore, a strong need exists to provide accurate data on oral relative bioavailability (RBA) of arsenic (in vivo or in vitro) in field-collected CCA-contaminated soils. The objectives of this study were (1) to assess arsenic bioaccessibility in contaminated soils collected near in-service CCA-treated utility poles, (2) to determine the influence of soil properties and arsenic fractionation on arsenic bioaccessibility, and (3) to estimate an average daily arsenic intake from incidental soil ingestion. Arsenic bioaccessibility (in vitro gastrointestinal (IVG) method) was determined on surface soil samples collected immediately adjacent to 12 CCA-treated utility poles after 18 months of service. Bioaccessible arsenic was also determined in 3 certified reference materials. Total arsenic concentrations in soils (RBA reported by Casteel et al. (2003) in soil near CCA-treated utility poles. Bioaccessible arsenic was positively correlated with total organic carbon content (r2 = 0.36, p < 0.05) and with water-soluble arsenic (2 = 0.51, p < 0.01), and was negatively correlated with clay content (r2 = 0.43, p < 0.05). Using conservative exposure parameters, the mean daily arsenic intake from incidental ingestion of contaminated soil near CCA-treated utility poles was 0.18 +/- 0.09 microg As kg(-1) d(-1). This arsenic intake appeared negligible compared to the daily intake of inorganic arsenic from water and food ingestion for children. PMID:16856753

  10. Effect of Palmyra Palm Leaf Ash on Cement Stabilization of Makurdi Shale

    Directory of Open Access Journals (Sweden)

    Amos Yala IORLIAM

    2012-08-01

    Full Text Available Makurdi Shale was treated with palmyra palm leaf ash (PPLA and cement to assess its suitability as a material in construction of flexible pavement. Classification, Compaction, Consistency, California bearing ratio (CBR and Unconfined compressive strength (UCS tests, were conducted on the shale specimen treated with, cement and PPLA in a combined incremental order of 2% up to 10% of cement and 2% up to 14% of PPLA of dry weight of soil sample respectively. Results of tests showed that Makurdi shale is an A-7-6, high plasticity (CH and high swell potential soil by the American Association of State Highway and Transportation Officials (AASHTO, Unified Soil Classification System (USCS and Nigerian Building and Road Research Institute (NBRRI classification systems respectively. The plasticity index (PI reduced from 30.5% for untreated Makurdi shale to 4% at 10% cement +14% PPLA contents. The maximum soaked CBR and 7 day UCS values of 92% and 1041 kN/m2 were obtained at 10% cement+14 % PPLA contents respectively. From the results, Makurdi shale treated with a combination of 10%cement+14% PPFA with a soaked CBR value of 92 %, 7 day UCS value of 1041 kN/m2 and 82 % value of resistance to loss in strength, satisfied the requirement for sub-base specification. It is therefore recommended for use as sub-base materials in flexible pavement.

  11. Mitigating the Expansive Behavior of Chemically Treated Soils

    OpenAIRE

    Jung, Sochan; Santagata, Maria Caterina

    2009-01-01

    Sulfate-induced heave, resulting from the chemical treatment of sulfate rich soils, has been known to cause significant damage to pavements and other structures particularly in the south-western United States. This research addressed the problem of sulfate-induced heave in coal mine spoils, formed as a result of shallow strip coal mining, after treatment with calcium-based stabilizers. These spoils occur in areas of Indiana in which substantial infrastructure development is taking place and w...

  12. 1-D Compression Behaviour of Acid Sulphate Soils Treated with Alkali-Activated Slag

    Directory of Open Access Journals (Sweden)

    Shahidul Islam

    2016-04-01

    Full Text Available Improvements of soft soils by mechanically mixing cementitious additives have been widely practised for construction of infrastructure. Mixing of additives improves strength and compressibility properties of soils through the development of soil structure. This study investigates the 1-D compression behaviour of alkali-activated slag treated acid sulphate soils (ASS cured up to 365 days. The void ratio-logarithm of pressure (e-logσ′ behaviour of treated ASS, including the destructuration behaviour, with additive contents and curing time have been analysed. X-ray diffraction (XRD and scanning electron microscopy (SEM analyses have been undertaken to explain the observed variations of the 1-D compression behaviour. This paper presents the results of these analyses in view of obtaining an insight into the 1-D compression behaviour of treated ASS with the help of mineralogical analysis.

  13. Study on the Relation between Material Composition and Performance of the Porous Composites of Cement Treated Crushed Stone%水泥稳定碎石多孔性材料的组成与性能探讨

    Institute of Scientific and Technical Information of China (English)

    李立寒; 郭忠印

    2001-01-01

    Aggregate gradation and cement content are important factors that affect the porousness,the permeability coefficient, the strength and modulus of cement treated crushed stone. Samples of five open-graded aggregates, and four levels of cement content were tested in"drainage-lag"permeameter developed by Barber and Sawyer, and then the samples were tested in compressive strength and modulus of resilience. The relations between material composition and performance of cement treated crushed stone were discussed and the regression equations were developed on the basis of laboratory tests and stepwise regression analysis. These results provide valuable guide for the mix design of cement treated crushed stone.%根据室内试验结果,对水泥稳定碎石多孔性材料的组成与其孔隙率、渗透系数、强度和模量的关系进行了分析,探讨了集料级配、水泥用量等因素的影响.通过逐步回归分析,建立了水泥稳定碎石材料组成与性能之间的回归公式.在此基础上,探讨了水泥稳定碎石的组成设计方法。

  14. Formation and preliminary in vitro evaluation of a zinc polycarboxylate cement reinforced with neat and acid-treated wollastonite fibers.

    Science.gov (United States)

    Greish, Yaser E; Hamdan, Najwa M; El Maghraby, Hesham F

    2012-05-01

    Zinc polycarboxylate dental cement is known to form both molecular and mechanical bonds with native tooth materials. However, its relatively weak mechanical properties limit its applications. Wollastonite fibers, with different aspect ratios, were blended with ZnO, prior to its mixing with polyacrylic acid, at weight percentages up to 25%. Setting time, density, compressive strength, and Young's modulus of the formed composites were determined. Composition and morphology of the composites were determined by XRD, IR, and SEM before and after treatment in simulated body fluids. A slight delay in the setting time of the composites was observed. An overall improvement in the compressive strength and modulus of these composites was observed up to 5 wt % of wollastonites, followed by a decrease with increasing the proportion of wollastonite in the composites. Immersion of these composites in SBF solutions resulted in the formation of apatite deposits on the surfaces of the reinforcing fibers.

  15. SOFT SOIL CONSOLIDATION BY THE MIXTURE OF INDUSTRIAL WASTE GYPSUM AND CEMENT%工业废石膏与水泥配合加固软土地基

    Institute of Scientific and Technical Information of China (English)

    黄新; 胡同安

    2001-01-01

    Improved soil strength by the mixture of waste gypsum and cement may be double that by mere cement. Optimal waste gypsum mixed is roughly 20% of cement by weight. When the method is adopted, in the hydrates of waste gypsum-cement, not only calcium silicate hydrate cementing loose soil particles together, but ettringite is produced by the reaction of cement with gypsum. It can expanse and fill up pores in the soil and then improve soil strength further.%利用工业废石膏与水泥配合加固软土地基,与单用水泥加固相比,加固土强度可成倍提高。废石膏的最佳掺量一般为水泥用量的20%左右。用废石膏-水泥加固时,其水化物中不仅有水化硅酸钙将松散的土粒胶结成整体,而且还产生大量钙矾石,其晶体膨胀填充孔隙,使加固土强度进一步提高。

  16. Using Iron to Treat Chlorohydrocarbon-Contaminated Soil

    Science.gov (United States)

    Hitchens, G. Duncan; Hodko, Dalibor; Kim, Heekyung; Rogers, Tom; Singh, Waheguru Pal; Giletto, Anthony; Cisar, Alan

    2004-01-01

    A method of in situ remediation of soil contaminated with chlorinated hydrocarbon solvents involves injection of nanometer-size iron particles. The present method exploits a combination of prompt chemical remediation followed by longer-term enhanced bioremediation and, optionally, is practiced in conjunction with the method of bioremediation described earlier. Newly injected iron particles chemically reduce chlorinated hydrocarbons upon contact. Thereafter, in the presence of groundwater, the particles slowly corrode via chemical reactions that effect sustained release of dissolved hydrogen. The hydrogen serves as an electron donor, increasing the metabolic activity of the anaerobic bacteria and thereby sustaining bioremediation at a rate higher than the natural rate.

  17. Effect of Treated Wastewater Irrigation on Heavy Metals Distribution in a Tunisian Soil

    Directory of Open Access Journals (Sweden)

    K. Khaskhoussy

    2015-06-01

    Full Text Available Treated wastewater (TWW may contain toxic chemical constituents that pose negative environmental and health impacts. In this study, soil samples under treated wastewater irrigation were studied. For this purpose, six plots were made in an irrigated area in north of Tunisia and treated with two water qualities: fresh water (FW and treated wastewater (TWW. Five soil depths were used: 0-30, 30-60, 60-90, 90-120 and 120-150 cm. The TWW irrigation increased significantly (P≤0.05 the soils’ EC, Na, K, Ca, Mg, Cl, SAR, Cu, Cd and Ni and had no significant (P ≤0.05 effect on the soils’ pH, Zn, Co and Pb contents. EC, Na, Cl, SAR, Zn and Co increased significantly with soil depth. The results for K, Ca, Mg, Cd, Pb and Ni exhibited similar repartition in different layers of soil. It was also shown that the amount of different elements in soil irrigated with fresh water (FW were less compared with the control soil

  18. Evolution of volatile sulfur compounds from soils treated with sulfur-containing organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Banwart, W.L.; Bremner, J.M.

    1976-01-01

    Release of volatile S compounds from soils treated with S-containing organic materials was studied. Methyl mercaptan, dimethyl sulfide, dimethyl disulfide, carbonyl sulfide and carbon disulfide were identified as gaseous products of decomposition of animal manures, sewage sludges and plant materials in soils under aerobic or waterlogged conditions. No release of hydrogen sulfide was detected. Most of the S volatilized from soils treated with sludges was in the form of dimethyl sulfide and dimethyl disulfide, whereas most of the S volatilized from soils treated with manures and plant materials was in the form of methyl mercaptan and dimethyl sulfide. More S compounds were released, and more S was volatilized, by decomposition of manures, sludges or plant materials in soils under waterlogged conditions than by decomposition under aerobic conditions. When calculated as a percentage of the S added as organic material, the average amount of S volatilized under aerobic or waterlogged conditions was < 0.2%, < 0.5% and < 3.4% for the sludges, manures and plant materials, respectively. The five volatile S compounds produced by decomposition of manures, sludges and plant materials in soils under aerobic and waterlogged conditions also were produced by decomposition of plant proteins (zein, gluten and gliadin). It is concluded that the volatile S compounds released by decomposition of the above organic materials in soils are largely, if not entirely, produced by microbial degradation of methionine and cystine in these materials. 17 references, 5 tables.

  19. Test Study on Construction Technology Improvement for Cement-soil Mixed Pile%水泥土搅拌桩施工工艺优化现场试验研究

    Institute of Scientific and Technical Information of China (English)

    郭涛

    2012-01-01

    水泥土搅拌桩强度主要影响因素包括组分配比、桩身水泥含量及均匀性、施工工艺等因素。本文通过对沿海某一高速公路工程的水泥土搅拌桩质量的检验,水泥搅拌桩质量最大的问题是水泥含量不均匀,存在明显的水泥团块,其主要原因是由施工工艺不合理造成的。水泥搅拌桩水泥含量不均匀通过将原先的喷浆搅拌施工改为喷粉搅拌施工,同时将二喷四搅的施工工艺改为三喷六搅,水泥搅拌桩质量有了较大提高,达到了设计要求。%The magor factors of strength of cement-soil mixed pile include mixture ratio of component, cement content, cement uniformity of pile body and construction technology. By means of quality inspection of cement-soil mixed pile of coastal express highway engineering, the main reason of disqualification for the pile is the irrational construction technology, which results in the existence of plenty of cement block mass and cement nonuiformity. The cement nonuiformity of pile is improved greatly by substituting spraying ce- ment power for cement paste, and by substituting three-spray and six-mix of construction technology for two-spray and four-mix. The quality of cement-soil mixed pile meets the demand of design.

  20. Ammonia-Oxidizer Communities in an Agricultural Soil treated with Contrasting Nitrogen Sources.

    Directory of Open Access Journals (Sweden)

    Mussie Y. Habteselassie

    2013-11-01

    Full Text Available The community of ammonia-oxidizing prokaryotes was examined in an agricultural soil treated for 6 seasons with contrasting nitrogen (N sources. Molecular tools based on the gene encoding ammonia monooxygenase were used to characterize the ammonia oxidizer communities and their abundance. Soil DNA was extracted from soils sampled from silage corn plots that received no additional N (control, dairy waste compost (DC, liquid dairy waste (LW, and ammonium sulfate (AS treatments at approximately 100 and 200 kg available N ha-1 over 6 years. The N treatment affected the quantity of ammonia oxidizers based on estimates of amoA by real-time PCR. Ammonia oxidizing bacteria (AOB were higher in soils from the AS200, AS100, and LW200 treatments (2.5 x107, 2.5x107, and 2.1 x107 copies g-1 soil, respectively than in the control (8.1x106copies/g while the abundance of amoA encoding archaea (AOA was not significantly affected by treatment (3.8x107copies g-1 soil, average. The ratio of AOA/AOB was higher in the control and compost treated soils, both treatments have the majority of their ammonium supplied through mineralization of organic nitrogen. Clone libraries of partial amoA sequences indicated AOB related to Nitrosospira multiformis and AOA related to uncultured Nitrososphaera similar to those described by soil fosmid 54d9 were prevalent. Profiles of the amoC-amoA intergenic region indicated that both Nitrosospira- and Nitrosomonas-type AOB were present in all soils examined. In contrast to the intergenic amoC-amoA profile results, Nitrosomonas-like clones were recovered only in the LW200 treated soil-DNA. The impact of six years of contrasting nitrogen sources applications caused changes in ammonia oxidizer abundance while the community composition remained relatively stable for both AOB and AOA.

  1. Examination of zinc adsorption capacity of soils treated with different pyrolysis products

    Directory of Open Access Journals (Sweden)

    Rétháti Gabriella

    2014-11-01

    Full Text Available Organic matter input into soils is essential regarding agricultural, environmental and soil science aspects as well. However, the application of the pyrolysed forms of biochars and materials with different organic matter content gained more attention in order to decrease the emission of the green house gases (CO2, N2O from the soil. During pyrolysis, the materials containing high organic matter (biomass-originated organic matter are heated in oxygen-free (or limited amount of oxygen environment. As a result, the solid phase, which remains after eliminating the gases and liquid phase, is more stable compared to the original product, it cannot be mineralized easily in the soil and its utilization is more beneficial in terms of climatic aspects. Furthermore, it can improve soil structure and it can retain soil moisture and cations in the topsoil for long periods of time, which is very important for plants. In our experiment, the effects of biochar and bone char were examined on soils by zinc adsorption experiments. Based on our experiments, we concluded that the pyrolysis products can have significant Zn adsorption capacity compared to the soil. Bone ash can adsorb more Zn than the charcoal product. The Zn adsorption capacity of soils treated by pyrolysis products can be described by Langmuir adsorption isotherms. However, based on the amount of pyrolysis products, one or two term Langmuir isotherm fits well on the experiment data, which depends on the time the pyrolysis product has spent in the soil.

  2. 饱和粉细砂水泥土强度特性试验研究%Experimental study on characteristics strength of cement soil saturated sand

    Institute of Scientific and Technical Information of China (English)

    魏建菊

    2015-01-01

    新建铁路格尔木至库尔勒线DK16+108-DK56+950段经过草滩、湿地、沼泽等地段,由于地下水位较高或常年积水,粉土、粉细砂呈松散、饱和状,强度低,工程性质差,设计拟采用水泥土搅拌桩对该段地基进行加固处理.通过试验对水泥、粉煤灰与饱和粉细砂搅拌后的无侧限抗压强度增长规律进行研究,探讨了饱和粉细砂水泥土无侧限抗压强度与"二灰"(水泥、粉煤灰掺合料)掺入比、养护龄期的关系.试验结果表明:水泥对饱和粉细砂具有良好的固化作用;饱和粉细砂的无侧限抗压强度随二灰掺入比的增大呈指数形式增长,随养护龄期的增大呈幂函数形式增长;回归分析表明具有良好的线性相关性,可以用28d强度对90d强度进行预测.%Golmud to Korla DK16+108-DK56+950 new railway through the marsh,swamp wetland, such as. Because of the high underground water level or perennial water, Silt, silty sand is loose, saturated, low strength, poor engineering properties, The design of the cement soil mixing pile in the foundation reinforcement treatment.Through the test of cement, fly ash and saturated sand after mixing theunconfined compressive strength increasing rule research, Discussion on the saturated sand cement soil unconfined compressivestrength and the "two ash" (cement, fly ash admixture) incorporationratio, curing age. Test results show that: the cement has good curing effect of saturated silty sand;Saturated sand soil unconfined compressive strength ratio increasesexponentially with the two ash incorporation, with increase of curing period as a power function of growth; Regression analysis showed that has a good linear correlation, 28d can be used to predict the strength of the strength of 90d.

  3. Risk assessment applications for determining cleanup limits for uranium in treated and untreated soils

    International Nuclear Information System (INIS)

    Uranium-contaminated soils are present at various locations across the US where uranium was processed for nuclear fuels or atomic weapons. Important issues relative to such contamination include the assessment of potential health risks associated with human exposures to the residual uranium and the determination of safe levels of uranium in soils that have been treated by a given technology. This paper discusses various risk assessment considerations that must be dealt with when developing cleanup limits for uranium in treated and untreated soils. Key issues addressed include alternative land use scenarios, potential exposure pathways, characterization of the bioavailability of uranium compounds in food and water, a brief overview of health risks associated with uranium and its daughter products as well as a summary of considerations for development of risk-based cleanup limits for uranium in soils

  4. Risk assessment applications for determining cleanup limits for uranium in treated and untreated soils

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, A.Q. [Oak Ridge National Lab., TN (United States); Layton, D.W. [Lawrence Livermore National Lab., CA (United States); Rutz, E.E. [Univ. of Cincinnati, OH (United States)

    1994-06-01

    Uranium-contaminated soils are present at various locations across the US where uranium was processed for nuclear fuels or atomic weapons. Important issues relative to such contamination include the assessment of potential health risks associated with human exposures to the residual uranium and the determination of safe levels of uranium in soils that have been treated by a given technology. This paper discusses various risk assessment considerations that must be dealt with when developing cleanup limits for uranium in treated and untreated soils. Key issues addressed include alternative land use scenarios, potential exposure pathways, characterization of the bioavailability of uranium compounds in food and water, a brief overview of health risks associated with uranium and its daughter products as well as a summary of considerations for development of risk-based cleanup limits for uranium in soils.

  5. A feasibility study to use coal tar contaminated soil in asphalt cement mixture production

    International Nuclear Information System (INIS)

    Coal tars are the residues produced during the gasification of coal. Traditionally, coal tars were buried onsite at the power plants or left as residuals in the bottom of gas holders. Currently, there are more than 1,500 such historic sites which will undergo site assessment in the near future. The use of coal tar residuals in asphalt-based products could result in greatly reduced disposal costs, in comparison to current methods of disposal. Present disposal practice of coal tar contaminated residuals includes disposal in hazardous waste landfills or incineration. Treatment and disposal costs are reported to be as much as $1,000/ton for current coal tar contaminated residuals disposal options. This feasibility study was performed to determine the use of coal tar contaminated soil (CTCS) in bituminous materials to produce hot asphalt mix. Mixtures of varying composition of CTCS and bituminous material were produced to perform TCLP. The air emissions during the mixing process were captured and analyzed. In this study, a bench scale investigation was performed to identify and quantify the emissions from heating the CTCS at the mixer temperature. The pilot scale investigations were performed by replacing reclaimable asphalt pavement (RAP) with CTCS during the hot asphalt mix production. The investigations were performed on two types of mixtures; using CTCS as the direct additive in the first type, and using SS-1 (slow setting asphalt emulsion) stabilized CTCS as an additive in the second type

  6. Challenges in treating earthen construction materials as unsaturated soils

    Directory of Open Access Journals (Sweden)

    Augarde Charles E.

    2016-01-01

    Full Text Available Earthen construction is a loosely defined term covering both the materials and methods for creating structural components from mixtures of subsoil, often with the addition of chemical or mechanical stabilisers. There is evidence of Man creating earthen structures for thousands of years, and there are many world heritage sites containing earthen structures, some of which present issues in terms of conservation. In some parts of the world there is a growing market for new-build earthen structures and a key issue here is the lack of design codes. Since these materials are composed mainly of particulates and water it is natural to regard them as geotechnical in nature, where friction and the presence of water have a key influence on material properties, however until very recently this was not the case, with earthen construction materials regarded as weak concrete or masonry. In this paper we examine these opposing views and discuss the issues associated with regarding these materials as unsaturated soils. The paper is illustrated with outcomes from research at Durham University carried out over the past ten years.

  7. Arsenic mobilization by citrate and malate from a red mud-treated contaminated soil.

    Science.gov (United States)

    Castaldi, Paola; Silvetti, Margherita; Mele, Elena; Garau, Giovanni; Deiana, Salvatore

    2013-01-01

    The mobility and bioavailability of As in the soil-plant system can be affected by a number of organic acids that originate from the activity of plants and microorganisms. In this study we evaluated the ability of citrate and malate anions to mobilize As in a polluted subacidic soil (UP soil) treated with red mud (RM soil). Both anions promoted the mobilization of As from UP and RM soils, with citrate being more effective than malate. The RM treatment induced a greater mobility of As. The amounts of As released in RM and UP soils treated with 3.0 mmol L citric acid solution were 2.78 and 1.83 μmol g respectively, whereas an amount equal to 1.73 and 1.06 μmol g was found after the treatment with a 3.0 mmol L malic acid solution. The release of As in both soils increased with increasing concentration of organic acids, and the co-release of Al and Fe in solution also increased. The sequential extraction showed that Fe/Al (oxi)hydroxides in RM were the main phases involved in As binding in RM soil. Two possible mechanisms could be responsible for As solubilization: (i) competition of the organic anions for As adsorption sites and (ii) partial dissolution of the adsorbents (e.g., dissolution of iron and aluminum oxi-hydroxides) induced by citrate or malate and formation of complexes between dissolved Fe and Al and organic anions. This is the first report on the effect of malate and citrate on the As mobility in a polluted soil treated with RM.

  8. Strength Characteristics of Lightweight Soil Amended by Cement-Modified Poly ( vinyl alcohol )%水泥-改性聚乙烯醇固化轻质土的强度特性

    Institute of Scientific and Technical Information of China (English)

    董金梅; 王沛; 柴寿喜

    2011-01-01

    为改善水泥固化轻质土存在的不足,采用水泥-改性聚乙烯醇(SH)对轻质土进行固化.分析探讨了水泥-SH固化轻质土的受压破坏方式、应力-应变曲线类型以及龄期、养护环境、SH掺量、土质成分对水泥-SH固化轻质土无侧限抗压强度的影响.结果表明:水泥-SH固化轻质土受压破坏没有出现明显的破裂面,且破坏应变较大,有较高的残余强度;室温养护下水泥-SH固化轻质土的无侧限抗压强度显著高于恒温恒湿养护;SH固化剂显著提高水泥固化轻质土无侧限抗压强度的最低掺量为4.5%(质量比);SH固化剂可以减小土质成分对水泥固化轻质土无侧限抗压强度的影响.%In order to amend the solidification of lightweight soil by cement, a new polymer binding material, I. E. Modified poly (vinyl alcohol) known as SH was added to cement to solidify the lightweight soil. The investigation includes failure types and stress-strain curves of cement-SH amended lightweight soils subjected to unconfined compressive(UC) tests, the effects of curing age and condition, SH use level, and soil types on the UC strength of cement-SH amended lightweight soils. Test results indicate that the cement-SH amended lightweight soils show no clear shear plane, but significant strain at peak shear strength and relatively high residual strength when exposed to UC tests. The UC strength of cement-SH amended lightweight soil subjected to air curing is greater than that subjected to steam curing. A minimum SH use level of 4. 5%(by mass) is suggested to enhance the UC strength of cement amended lightweight soil. SH solidifier mitigates the influence of soil types on UC strength of cement amended lightweight soil.

  9. Physical-chemical effects of irrigation with treated wastewater on Dusky Red Latosol soil

    Directory of Open Access Journals (Sweden)

    Vanessa Ribeiro Urbano

    2015-11-01

    Full Text Available The current water crisis underlines the importance of improving water management. The use of effluent from secondary treatment in agriculture can reduce the discharge of effluent into natural bodies and provide nutrients to crops. This study evaluated the physical and chemical properties of a Dusky Red Latosol soil that had been irrigated with treated wastewater. Conducted at the Center of Agricultural Sciences (CCA of Federal University of São Carlos (UFSCar, in Araras/São Paulo/Brazil, 18 undisturbed soil samples were collected and deposited on a constant-head permeameter in order to simulate the irrigation of five growth cycles of lettuce (Lactuca sativa L., organized in five different treatments and one control group. For each treatment 0.58 L, 1.16 L, 1.74 L, 2.32 L, and 2.90 L of treated wastewater and distilled water were applied . The treated wastewater came from a domestic waste treatment plant. After the water filtered through the soil, samples of treated wastewater were collected for analyses of electrical conductivity (EC, sodium adsorption ratio (SAR, turbidity, pH, Na, K, Mg, P and Ca and, in the soil the granulometry, complete fertility, exchangeable sodium percentage (ESP and saturated hydraulic conductivity (Ksat. The Ksat decreased, but did not alter the infiltration of water and nutrients in the soil. The concentration of nutrients in the soil increased, including Na, which raises the need for monitoring soil’s salinity. In conclusion, the application of wastewater did not cause damage to the physical properties of the soil, but resulted in a tendency towards salinization.

  10. Influence of freezing and thawing cycles on mechanical properties of closed-cell expanded perlite cemented soil%冻融循环对闭孔珍珠岩水泥土力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    侯宇慧; 申向东

    2013-01-01

    Due to poor frost resistance of cement-soil,in permafrost and seasonal frozen soil area,the application and promotion of the soil cement is subject to a certain limit,how to improve the strength and durability of cemented soil in repeated freeze-thaw conditions to ensure the service life of the engineering is the key for further promotion and application of soil cement material in cold regions.By adding closed-cell expanded perlite in cemented soil,it came to the strength that cemented soil in different closed-cell expanded perlite under freezing and thawing cycles,analyzed the effect of freezing and thawing cycles on closed-cell expanded perlite and the changes before and after freezing and thawing cycles closed-cell expanded perlite cemented soil.The cemented soil adding closed-cell expanded perlite are preliminary analyzed.%由于水泥土抗冻性能较差,在多年冻土和季节性冻土地区,水泥土的应用和推广受到了一定的限制,如何提高反复冻融条件下水泥土的强度和耐久性,保证工程的使用寿命,是水泥土材料在寒冷地区进一步推广应用的关键.通过在水泥土中加入闭孔珍珠岩,得出水泥土在不同闭孔珍珠岩掺量下冻融循环后的强度值,分析了冻融循环次数对闭孔珍珠岩水泥土性能的影响及冻融循环前后闭孔珍珠岩水泥土强度变化,对掺入闭孔珍珠岩的水泥土做了初步的机理分析.

  11. EXPERIMENTAL STUDY ON ASBESTOS FIBER REINFORCED FLY ASH SOIL-CEMENT FOR SOFT SOIL ENHANCEMENT%石棉纤维粉煤灰水泥加固软土试验研究

    Institute of Scientific and Technical Information of China (English)

    张艳军; 于沉香; 凌飞; 严稳平; 刘续; 陈铂

    2015-01-01

    This paper aims to improve the brittle fracture characteristics of cement soil and to study the engineering properties and mechanical mechanism of asbestos fiber reinforced soft soil.It adds the asbestos fiber into fly ash and cement soil.Thus it creates a new kind of composite soil and carries out a series of experiments on the new soil.In these experiments,asbestos fiber is added into fly ash and cement soil with different ratios(0%~9%),which results in different composite soil samples with different content of asbestos fiber.All of the composite soil samples are subjected to the direct shear test,the unconfined compression test,the diametral compression test and the scanning electron microscopy test (SEM).Thus the mechanical behavior and mechanism of fiber reinforced soft soil are illustrated.It is found that the combination of asbestos fiber and fly-ash cement can significantly enhance the strength and stability of soft soil and improve brittle fracture characteristics of cement soil.There is a range of optimal content of asbestos fiber regarding the enhancement of the strength value of the composite soil.This range is between 3%~6%.Other asbestos fiber content outside the range can reduce the enhancement effect.%为研究石棉纤维加固软土的效果和机理,改善水泥土的脆性破坏特点,提出将石棉纤维的物理加筋作用与水泥、粉煤灰的化学加固作用相结合,通过对不同纤维掺量(0%~9%)的石棉纤维粉煤水泥复合土进行直剪试验、无侧限抗压强度试验、劈裂试验、扫描电镜试验,进而对石棉纤维加筋水泥土的强度性质和影响机理进行探讨。研究表明,石棉纤维配合水泥与粉煤灰能显著提高软土的强度和稳定性,改善水泥土的破坏形式。水泥粉煤灰配比一定时,石棉纤维增强水泥复合土各强度指标值存在最优掺量,纤维添加量在3%~6%之间,石棉纤维的加筋效果在水泥土中能得到

  12. Calculating carbon mass balance from unsaturated soil columns treated with CaSO₄₋minerals: test of soil carbon sequestration.

    Science.gov (United States)

    Han, Young-Soo; Tokunaga, Tetsu K

    2014-12-01

    Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260 g C m(-1) infiltrated water (20-120 g C m(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment.

  13. Controllability of runoff and soil loss from small plots treated by vinasse-produced biochar.

    Science.gov (United States)

    Sadeghi, Seyed Hamidreza; Hazbavi, Zeinab; Harchegani, Mahboobeh Kiani

    2016-01-15

    Many different amendments, stabilizers, and conditioners are usually applied for soil and water conservation. Biochar is a carbon-enriched substance produced by thermal decomposition of organic material in the absence of oxygen with the goal to be used as a soil amendment. Biochar can be produced from a wide range of biomass sources including straw, wood, manure, and other organic wastes. Biochar has been demonstrated to restore soil fertility and crop production under many conditions, but less is known about the effects of its application on soil erosion and runoff control. Therefore, a rainfall simulation study, as a pioneer research, was conducted to evaluate the performance of the application of vinasse-produced biochar on the soil erosion control of a sandy clay loam soil packed in small-sized runoff 0.25-m(2) plots with 3 replicates. The treatments were (i) no biochar (control), (ii) biochar (8 tha(-1)) application at 24h before the rainfall simulation and (iii) biochar (8 tha(-1)) application at 48 h before the rainfall simulation. Rainfall was applied at 50 mm h(-1) for 15 min. The mean change of effectiveness in time to runoff could be found in biochar application at 24 and 48 h before simulation treatment with rate of +55.10% and +71.73%, respectively. In addition, the mean runoff volume 24 and 48 h before simulation treatments decreased by 98.46% and 46.39%, respectively. The least soil loss (1.12 ± 0.57 g) and sediment concentration (1.44 ± 0.48 gl(-1)) occurred in the biochar-amended soil treated 48 h before the rainfall simulation. In conclusion, the application of vinasse-produced biochar could effectively control runoff and soil loss. This study provided a new insight into the effects of biochar on runoff, soil loss, and sediment control due to water erosion in sandy clay loam soils.

  14. FIELD EVALUATION OF THE LIGNIN-DEGRADING FUNGUS PHANEROCHAETE SORDIDA TO TREAT CREOSOTE-CONTAMINATED SOIL

    Science.gov (United States)

    A field study to determine the ability of selected lignin-degrading fungi to remediate soil contaminated with creosote was performed at a wood-treating facility in south central Mississippi in the autumn of 1991. The effects of solid-phase bioremediation with Phanerochaete sordid...

  15. Strategies for Treating and Dewatering Contaminated Soils and Sediments Simultaneously - 13389

    Energy Technology Data Exchange (ETDEWEB)

    Bickford, Jody; Foote, Martin [MSE Technology Applications, Inc., 200 Technology Way, Butte, MT 59701 (United States)

    2013-07-01

    MSE Technology Applications, Inc. (MSE) was asked to perform a series of treatability studies by Global Technologies, Inc. (Global) and M{sup 2} Polymer Technologies, Inc. (M{sup 2} Polymer) using Global's metal treatment agent, Molecular Bonding System (MBS) and M{sup 2} Polymer's super-absorbent polymer, Waste Lock 770 (WL-770). The primary objective of the study was to determine if the two products could be used as a one-step treatment process to reduce the leachability of metals and de-water soils and/or sediments simultaneously. Three phases of work were performed during the treatability study. The first phase consisted of generating four bench-scale samples: two treated using only MBS and two treated using only WL- 770, each at variable concentrations. The second phase consisted of generating nine bench-scale samples that were treated using MBS and WL-770 in combination with three different addition techniques. The third phase consisted of generating four intermediate-scale samples that were treated using MBS and WL-770 simultaneously. The soils used in the treatability study were collected at the Mike Mansfield Advanced Technology Center in Butte, Montana. The collected soils were screened at 4 mesh (4.75 millimeters (mm)) to remove the coarse fraction of the soil and spiked with metallic contaminants of lead, cadmium, nickel, mercury, uranium, chromium, and zinc. (authors)

  16. Transformation of organic N newly added to red soil treated with different cultural practices

    Institute of Scientific and Technical Information of China (English)

    ZhangQin-Zheng; YeQing-Fu; 等

    1998-01-01

    By using 15N tracer method,transformation of organic N,which wqas newly added to red soil treated with different cultural practices,was studied under thelaboratory incubation condition.The experimental results showed that the transformation of N from newly added organic matter and soil native pool during incubation was influenced by cultural practice treatment beforeincubation.Fallow was favorable to the mineralization of newly added organic N and soil N compared with the planting wheat treatment.Planting wheat greatly increased the loss of soil N.Application of fertilizers stimulated the mineralization of newly added organic N and application of organic matter reduced the mineralization,but stimulated microbialtransformation of newly adde4d organic N.

  17. Bearing Behaviors of Rubberized Cement-Soil Pile Composite Foundation%橡胶水泥土桩复合地基的承载性状

    Institute of Scientific and Technical Information of China (English)

    王凤池; 史富民; 徐云龙; 刘凤起

    2011-01-01

    通过橡胶水泥土桩复合地基室内载荷试验,研究了橡胶水泥土桩复合地基的承载特性及橡胶粉掺量的影响.对于橡胶水泥土单桩复合地基,桩土荷载随上部荷载变化存在再分配过程.桩土应力比在加载过程中非定值,曲线呈上单凸峰变化.褥垫层厚度对橡胶水泥土单桩复合地基的桩土应力比同样有调节作用.随着橡胶粉掺量的增加,复合地基的比例界限值增加;桩身的应变增大并沿随桩身高度呈显著线性变化;桩土应力比值减小.研究表明,合理调整桩身橡胶粉掺量可以优化桩土应力比,改善复合地基承载性能.%Through indoor load tests on rubberized cement-soil pile composite foundation, its bearing behavior and the influences of rubber powder content were studied. For the rubberized cement-soil pile composite foundation, the bearing load of pile and soil is redistributed when the upper load changes. The value of pile-soil stress ratio is not definite in the loading process and the shape of pile-soil stress ratio curve has single upper leptokurtosis. The thickness of cushion also has regulating effect on pile-soil stress ratio. With the rubber powder content increasing, the ratio limit value of composite foundation increases; the strain along pile body height increases linearly significantly and the pile-soil stress ratio decreases. The results show that reasonable adjustment of rubber powder content can optimize the pile-soil stress ratio and improve the bearing capacity of composite foundation.

  18. Parametrization of organic nitrogen mineralization models in soil treated with swine raising wastewater

    Directory of Open Access Journals (Sweden)

    Demétrius David da Silva

    2010-08-01

    Full Text Available Little is known about the mineralization dynamic of organic nitrogen contained in swine manure, so models need to be adjusted for its prediction. The objective of the present study was to parameterize and assess models of organic nitrogen mineralization in soil treated with swine raising wastewater (SRW at different temperatures and water contents. Samples of 57.3 cm3 of dystrophic Red-Yellow Latosol were mixed with SRW at the application dose of 400 kg ha-1 nitrogen, placed in plastic cups and incubated at four different temperatures (15, 20, 25 and 35°C and water contents corresponding to tensions of 10, 30, 200 and 1500 kPa. Samples were removed from the incubated soil after 3, 6, 12, 24, 48 and 96 days to quantify the ammonium and nitrate concentrations. The parameters of the soil organic nitrogen mineralization models were determined from the organic nitrogen mineralization values obtained over the different incubation periods. The value of the potentially mineralizable nitrogen (N0 in soil with application of SRW was superior that of the soil without application of SRW. The mineralization constant (k in soil with application of SRW was always superior that of the soil without application of SRW. There was a tendency for the simple exponential model to underestimate the values of the mineralized nitrogen concentration. In most of the situations the potential model was more efficient than the simple exponential model to predict the mineralization of the organic nitrogen.

  19. 掺加纳米材料水泥土无侧限抗压强度试验研究∗%Research on Unconfined Compressive Strength of Soil Cement with Nano Structured Materials

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    把纳米SiO2、纳米Al2 O3和纳米蒙脱土3种纳米材料加入普通水泥土中,制备掺加纳米材料的水泥土。通过室内无侧限抗压强度试验,研究不同纳米材料及其掺量、龄期、水泥掺量、水胶比对添加纳米材料水泥土无侧限抗压强度的影响,为添加纳米材料水泥土的进一步研究及其在实际工程中的应用提供了方向。%Nano⁃SiO2 , nano⁃Al2 O3 and nano⁃montmorillonite are added into plain soil cement as the admixtures. The influence of various factors including the variety and content of nano structured materials, the age, the content of cement, the water⁃to⁃binder ( the sum of cement and nano structured materials) ratio on the unconfined compressive strength of soil cement is studied. The direction of the further study and the practical application of soil cement with nano structured materials is provided.

  20. Experimental analysis of the engineering features of zinc-contaminated soils solidified by the phosphate rock-cement%磷矿粉-水泥固化Zn污染土工程特性试验研究

    Institute of Scientific and Technical Information of China (English)

    王舒

    2016-01-01

    为揭示磷矿粉-水泥固化Zn污染土的工程性质,通过含水量、干密度、pH值测试和无侧限抗压强度试验,研究了两种固化土的物理力学性质随Zn质量分数和养护龄期的变化规律,探讨了重金属Zn对不同固化剂固化效果的影响,同时分析了固化土抗压强度与物理性质指标间的相关关系.结果表明:磷矿粉-水泥固化剂(PMC)固化Zn污染土的效果优于水泥固化土;PMC固化土的含水量变化率高于水泥固化土的,少量Zn可促进水化反应的进行,Zn质量分数大于0.5%时水化反应受到明显阻滞;PMC固化土的干密度比同条件下水泥固化土提高约6%,其pH值低于水泥固化土的,且集中在8.0~9.5;PMC主要通过吸附作用固化重金属,固化土的应力-应变特征为“软化”型,重金属Zn使得水泥固化土的应力-应变特征由“脆性”向“韧性”转变.%The paper is to devote itself to an experimental analysis of the engineering features of zinc-contaminated soil solidified by the phosphate rock-cement by illustrating and discussing the regularities of the basic engineering features of such Zn-contaminated clay.For the study purpose,the paper has conducted a series of laboratory tests,such as the moisture content test,the dry density test,the pH value and the unconfined compression strength test with the increase of Zn mass fraction and treating time length,in addition to the effects of heavy metal Zn traced on the solidification of the two different solidifiers.What is more,it has also analyzed the relation between the unconfined compression strength and the physical feature indexes of Zn-contaminated clay.The above experimenting and testing results show that the phosphate rock (PR)-cement solidifier (PMC) can help to strengthen Zn-contaminated clay effectively with the effect of Zncontaminated clay solidified by the phosphate rock (PR)-cement a lot better than that solidified by the cement merely.The changing rate

  1. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    OpenAIRE

    Nediljka Gaurina-Međimurec; Davorin Matanović; Gracijan Krklec

    1994-01-01

    During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures) and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production...

  2. Leaching from CCA-Treated Wood into Soils: Preliminary PIXE Studies

    Science.gov (United States)

    Kelly, R. F.; Kravchenko, I. I.; Kuharik, J. C.; Van Rinsvelt, H. A.; Dunnam, F. E.; Huffman, J.

    2003-08-01

    Widespread use of chromated copper arsenate (CCA) as a wood preservative has led to increasing public concern regarding possible toxic contamination of areas surrounding CCA-treated structures, e.g., decks, playground equipment, etc. Appreciable leaching of arsenic, chromium, and copper into soils adjacent to such structures has been demonstrated via standard techniques of analytical chemistry. The advantages of PIXE [rapid analysis, quick sample turnover, possible lower cost] suggest its application to this area of interest. PIXE studies in our laboratory of CCA-contaminated soil samples show good agreement with previous analyses of As, Cu, Cr, and other heavy-elemental content, with some variability in diffusion rates.

  3. Experimental analysis of effects of polluted water environment on mechanical properties of cemented soil%污水环境对水泥土力学性能的影响试验研究

    Institute of Scientific and Technical Information of China (English)

    陈四利; 杨雨林; 张精禹

    2015-01-01

    由于多数地下水泥土工程直接与地下腐蚀性介质环境接触,必将导致水泥土材料的逐步劣化甚至失效破坏。以某市区工地附近明渠排放的污水作为侵蚀性介质,制作了不同水泥掺量的水泥土试件,通过对比试验,研究了污水环境和清水环境下不同水泥掺量、不同龄期的水泥土抗压强度和抗剪强度。结果表明,在污水或清水环境下,相同水泥掺量水泥土30 d 龄期的抗压强度几乎相等,随着龄期的增加其抗压强度均逐步增大,但污水环境下其抗压强度增长的幅度明显小于清水环境,90 d 后清水环境的水泥土抗压强度不再增长,而污水环境的抗压强度开始降低;污水环境和清水环境下的水泥土内摩擦角和黏聚力随龄期、水泥掺量的增加均逐步增大,污水环境下龄期90 d后的内摩擦角和黏聚力均开始降低。%The majority of underground cemented soil projects contact with underground corrosive medium environment directly,which will lead to the deterioration of cemented soil material gradually or even failure.The discharged polluted water from the open channel near construction site is used as a kind of corrosive medium to produce test pieces of cemented soil with different cement content.In both polluted water environment and clean water environment,the compressive strength and shear strength of cemented soil with different cement content and different ages are compared.The results show that when the age is 30 days,compressive strength of cemented soil with the same cement content is almost the same in polluted water environment and clean water environment. Compressive strength of cemented soil gradually increases with the increase of the age.However,the increase extent of compressive strength in polluted water environment is significantly less than that in clean water environment.After 90 days,compressive strength of cemented soil no longer increases in

  4. Bioavailable Cu and major soil cations in contaminated soils treated with EDDS

    OpenAIRE

    Michálková, Zuzana

    2012-01-01

    Soil contamination with metals originating from anthropogenic activities becomes a serious problem throughout the world. The main sources are considered to be the mining and smelting industry, burning of fossil fuels, waste treatment and mineral fertilizers, pesticides, sewage sludges and sediments application. Regulatory standards have been developed for trace metals in the environment in order to protect human health and the ecosystems. Therefore, there is an effort to remediate or stabiliz...

  5. Salinity effect of irrigation with treated wastewater in basal soil respiration in SE of Spain

    Science.gov (United States)

    Morugan, A.; Garcia-Orenes, F.; Mataix-Solera, J.

    2012-04-01

    The use of treated wastewater for the irrigation of agricultural soils is an alternative to utilizing better-quality water, especially in semiarid regions where water shortage is a very serious problem. Wastewater use in agriculture is not a new practice, all over the world this reuse has been common practice for a long time, but the concept is of greater importance currently because of the global water crisis. Replacement of freshwater by treated wastewater is seen as an important conservation strategy contributing to agricultural production, substantial benefits can derive from using this nutrient-rich waste water but there can also be a negative impact. For this reason it is necessary to know precisely the composition of water before applying it to the soil in order to guarantee minimal impact in terms of contamination and salinization. In this work we have been studying, for more than three years, different parameters in calcareous soils irrigated with treated wastewater in an agricultural Mediterranean area located at Biar (Alicante, SE Spain), with a crop of grape (Vitis labrusca). Three types of waters were used for the irrigation of the soil: fresh water (control) (TC), and treated wastewater from secondary (T2) and tertiary treatment (T3). Three different doses of irrigation have been applied to fit the efficiency of the irrigation to the crop and soil type during the study period. A soil sampling was carried out every four months. We show the results of the evolution of basal soil respiration (BSR), and its relationship with other parameters. We observed a similar pattern of behavior for BSR between treatments, a decrease at the first eighteen months of irrigation and an increase at the end of study. In our study case, the variations of BSR obtained for all the treatments seem to be closely related to the dose and frequency of irrigation and the related soil wetting and drying cycles. However, the results showed a negative correlation between BSR and

  6. 土工格栅复合夯实水泥土桩-土界面接触特性分析%Study on the Contact Characteristics of Geogrid Composite Cement Soil Pile-Soil Interface

    Institute of Scientific and Technical Information of China (English)

    曹祚省; 何杰; 杨彦忠; 饶迁根; 孟森松

    2014-01-01

    Aiming at the interface friction traits of pile-soil, arranges the geogrid in the compacted soil cement pile-soil interface to enhance the interaction between rammed cement-soil pile and soil. Applies 3D numerical software to simulate direct shear test and static load test, analyzes the contact surface stress, deformation and intensity variation for the geogrid composite cement-soil pile and soil. The results show that the interface peak frictional resistance will increase, and the frictional resistance curve declines slowly when reaching the peak value;In the static load test, with geogrid around the pile, the corresponding subgrade settlement is smaller than that without geogrid, and the pile axial deformation is much smaller.%针对桩-土接触面的摩擦特性,在夯实水泥土桩-土界面中设置土工格栅,以增强夯实水泥土桩-土的相互作用。采用三维数值软件模拟直接剪切试验和静载试验,对土工格栅复合夯实水泥土桩-土界面接触特性进行分析,研究土工格栅复合夯实水泥土桩-土接触面的应力、变形和强度的变化规律。结果表明:土工格栅复合夯实水泥土桩-土接触界面的摩阻力峰值有所增加,达到峰值后,摩阻力曲线下降速率缓慢;静载试验中,在夯实水泥土桩表面复合土工格栅后,对应的基础沉降比普通夯实水泥土桩复合地基的沉降小,且夯实水泥桩的轴向压缩变形也小。

  7. Measurement of DDT fluxes from a historically treated agricultural soil in Canada.

    Science.gov (United States)

    Kurt-Karakus, Perihan Binnur; Bidleman, Terry F; Staebler, Ralf M; Jones, Kevin C

    2006-08-01

    Organocohlorine pesticide (OCP) residues in agricultural soils are of concern due to the uptake of these compounds by crops, accumulation in the foodchain, and reemission from soils to the atmosphere. Although it has been about three decades since DDT was banned for agricultural uses in Canada, residues persist in soils of some agricultural areas. Emission of DDT compounds to the atmosphere from a historically treated field in southern Ontario was determined in fall 2004 and spring 2005. The sigmaDDTs concentration in the high organic matter (71%) soil was 19 +/- 4 microg g(-1) dry weight. Concentration gradients in the air were measured at 5, 20, 72, and 200 cm above soil using glass fiber filter-polyurethane foam cartridges. Air concentrations of sigmaDDTs averaged 5.7 +/- 5.1 ng m(-3) at 5 cm and decreased to 1.3 +/- 0.8 ng m(-3) at 200 cm and were 60-300 times higher than levels measured at a background site 30 km away. Soil-air fugacity fractions, fs/(fs + fa), of p,p'-DDE, p,p'-DDD, and p,p'-DDT ranged from 0.42 to 0.91 using air concentrations measured above the soil and > or = 0.99 using background air concentrations, indicating that the soil was a net source to the background air. Fractionation of DDT compounds during volatilization was predicted using either liquid-phase vapor pressures (PL) or octanol-air partition coefficients (KOA). Relative emissions of p,p'-DDE and p,p'-DDT were better described by PL than KOA, whereas either PL or KOA successfully accounted for the fractionation of p,p'-DDT and o,p'-DDT. Soil-to-air fluxes were calculated from air concentration gradients and turbulent exchange coefficients determined from micrometeorological measurements. Average fluxes of sigmaDDTs were 90 +/- 24 ng m(-2) h(-1) in fall and 660 +/- 370 ng m(-2) h(-1) in spring. Higher soil temperatures in spring accounted for the higher fluxes. A volatilization half-life of approximately 200 y was estimated for sigmaDDT in the upper 5 cm of the soil column, assuming

  8. Carbon dynamics in an almond orchard soil amended with raw and treated pig slurry

    Science.gov (United States)

    Domínguez, Sara G.; Zornoza, Raúl; Faz, Ángel

    2010-05-01

    In SE Spain, intensive farming is very common which supposes the generation of great amounts of pig slurries. These residues cause many storage problems due to their pollution capacity. A good management of them is necessary to avoid damages to the environment. The use of this effluent as fertilizer is a usual practice that in the correct dose is a good amend and important for sustainable development, but in excess can be a risk of polluting and damaging soil, water and crop conditions. Pig slurry is a source of many nutrients and specially rich in organic matter. The main objective of this study is to determine changes in soil organic carbon dynamics resulting from raw and treated slurry amendments applied in different doses. The experimental area is an almond orchard located in Cartagena (SE Spain). The climate of the area is semiarid Mediterranean with mean annual temperature of 18°C and mean annual rainfall of 275 mm. A total of 10 plots (12 m x 30 m) were designed, one of them being the control without fertilizer. Surface soil samples (0-25 cm) were collected in September 2009. Three different treatments were applied, raw slurry, the effluent obtained after solid-liquid separation and solid manure, all of them in three doses being the first one of 170 kg N/ha, (maximum permitted in nitrates directive 91/676/CEE), and the others two and three times the first one. Soil biochemical parameters are rapid indicators of changes in soil quality. According to this, total organic carbon, soil microbial biomass carbon, soluble carbon, and β-glucosidase, β-galactosidase and arylesterase activities were measured in order to assess some soil biochemical conditions and carbon dynamics in terms of the different treatments. As we expected, the use of these organic fertilizers rich in organic matter, had an effect on soil carbon and soil microbial activity resulting in an increase in most of the parameters; total organic carbon and β-galactosidase activity showed the

  9. Bearing behavior of column-soil-cushion mutual action in composite foundation with rammed cement-soil column%夯实水泥土桩复合地基中桩-土-垫层共同作用机理

    Institute of Scientific and Technical Information of China (English)

    何杰; 张可能; 刘杰; 吴有平; 李冰

    2012-01-01

    基于剪切位移法,引入Mylonakis & Gazetas桩-土相互作用及温克尔地基模型,导出复合地基中桩-桩、桩-土及土-土相互作用柔度系数计算式;在此基础上,考虑垫层的影响,提出路堤荷载作用下桩-土-垫层共同作用分析的新方法,并利用Matlab软件编制相应的计算程序.以夯实水泥土桩复合地基为例,进行路堤荷载下夯实水泥土桩复合地基的室内模型试验,探讨垫层模量及厚度对桩与土差异沉降的影响.研究结果表明:在路堤荷载作用下,设置合适的柔性垫层,能有效增加桩体承担荷载的比例,发挥桩的承载能力,减少桩与桩间土之间的差异沉降及复合地基的沉降,改善复合地基的工作性状.%Based on the shear displacement method and the Mylonakis & Gazetas model for interaction between pile and soil, and the Winkler's layered foundation model was introduced, the calculation formulae of the flexibility coefficients for interaction between pile and pile, pile and soil, soil and soil were obtained. Considering the performance of cushion, a new analysis method on pile-soil-cushion mutual action under the embankment was suggested, and the correlated program was developed by Matlab software. Taking the composite foundation with the rammed soil-cement columns as an example, the model test of the composite foundation with the rammed soil-cement columns was performed under the embankment, the influences of the cushion modulus and thickness on the differential settlement between column and soil were discussed. The results show that under embankment load, column may play a better role, and the load sharing of soil surrounding columns and differentia settlement among columns and soils may be reduced to improve the working properties of composite foundation by setting the appropriate soft cushion.

  10. Shock-treated lunar soil simulant: Preliminary assessment as a construction material

    Science.gov (United States)

    Boslough, Mark B.; Bernold, Leonhard E.; Horie, Yasuyuki

    In an effort to examine the feasibility of applying dynamic compaction techniques to fabricate construction materials from lunar regolith, preliminary explosive shock-loading experiments on lunar soil simulants were carried out. Analysis of our shock-treated samples suggests that binding additives, such as metallic aluminum powder, may provide the necessary characteristics to fabricate a strong and durable building material (lunar adobe) that takes advantage of a cheap base material available in abundance: lunar regolith.

  11. Effect of Strength Enhancement of Soil Treated with Environment-Friendly Calcium Carbonate Powder

    OpenAIRE

    Kyungho Park; Sangju Jun; Daehyeon Kim

    2014-01-01

    This study aims to investigate the effects of the strength improvement of soft ground (sand) by producing calcium carbonate powder through microbial reactions. To analyze the cementation effect of calcium carbonate produced through microbial reaction for different weight ratios, four different types of specimens (untreated, calcium carbonate, cement, and calcium carbonate + cement) with different weight ratios (2%, 4%, 6%, and 8%) were produced and cured for a period of 3 days, 7 days, 14 day...

  12. Curing conditions Influence on Some Engineering Properties of Lime-treated expansive Clayey Soil from Mosul Area

    Directory of Open Access Journals (Sweden)

    Suhel E. AbdulKhader

    2013-05-01

    Full Text Available The aim of this work is to study the effect of varying curing conditions, namely temperature ( 10o to 60odegrees Celsius and curing period (2 to 90 days on the unconfined compressive strength (UCS and hydraulic conductivity of lime treated clayey soil selected from Mosul city. The soil was treated with (2,4 and 6% hydrated lime. Test results showed that the UCS was increased with the increase of curing temperature especially at low curing period. On the other hand, hydraulic conductivity in treated soil has increased with temperature compared with that of untreated soil but not with a constant trend. Finally, leaching of treated soil has led to a decline in hydraulic conductivity with time, while the rate of decreasing was found to be more with samples exposed to higher temperature.      

  13. CURING CONDITIONS INFLUENCE ON SOME ENGINEERING PROPERTIES OF LIME-TREATED EXPANSIVE CLAYEY SOIL FROM MOSUL AREA

    Directory of Open Access Journals (Sweden)

    Suhael I. Abdulkader

    2013-05-01

    Full Text Available This aim of the present work is to study the effect of varying curing conditions namely temperature that was studied within rang from 10o to 60odegrees Celsius. Curing period between two to ninety days was also studied for the unconfined compressive strength (UCS & hydraulic conductivity of lime treated clayey soil selected for Mosul city. The soil was treated with (2,4 and 6% hydrated lime. Test Results showed that the UCS was increased with curing temperature increase especially at lower curing period. On the other hand, hydraulic conductivity of treated soil has increased with temperature compared with that of untreated soil but not with  constant trend. Finally, leaching of treated soil has led to a decline in hydraulic conductivity with time, while the rate of decreasing was found to be more with samples exposed to higher temperature effect.        

  14. 水饱和条件下的水泥土抗压试验意义%The Signiifcance of Cement Soil Compression Test under the Water Saturated Condition

    Institute of Scientific and Technical Information of China (English)

    胡桂宝; 周建民; 高乔明

    2015-01-01

    The test of pile body quality of cement soil mixing pile usually use the core and retention samples for unconfined compressive strength test. Unconfined compressive strength test of cement soil has been described in many codes,but not specific for the regulations of moisture content when testing pressure test. Moisture content is one of the most important factors affecting the compress strength of cement soil. In engineering practice,cement soil mixing piles were often under the ground water level which was usually destroyed in the saturated state. Therefore,it's very significant to study the water saturation state as a necessary condition for the compressive test of cement soil.%水泥土搅拌桩的桩身质量检测,通常采用取芯和留样进行无侧限抗压强度试验.水泥土无侧限抗压强度试验在很多规范中均有阐述,但对于试件试压时的含水率规定得并不够具体.含水率是影响水泥土抗压强度重要的因素之一,工程实践中,水泥土搅拌桩往往处于地下水位以下,其破坏时通常处于饱和状态,因此研究水饱和状态作为水泥土抗压试验的必要条件是很有意义的.

  15. Durability of Salty Soil-Cement Mixed Pile in the Yellow River Delta%黄河三角洲改性含盐水泥土搅拌桩耐久性研究

    Institute of Scientific and Technical Information of China (English)

    崔新壮; 张娜; 王聪; 车华桥; 周亚旭

    2013-01-01

    A series of tests were carried out to study the deterioration of soil-cement in the Yellow River delta,and the suppression effect of different additives (fly-ash,GGBS(ground granulated blast furnace slag)) on the soil-cement deterioration.X-ray diffraction analyzer and scanning electron microscopy(SEM)were employed to study the deterioration mechanism of the soil-cement and the modification mechanism of additives material.Results indicate that the underground salt water is significantly corrosive to soil-cement.Compared with the normal soil-cement,the compressive strength of salty soil-cement was 18.5%lower after 90 days and 21.6% lower after 180 days.With the addition of fly-ash,the initial strength of salty soil-cement decreases,however,the long-term strength increases gradually.GGBS can significantly increase the strength and enhance the ability of restraining deterioration of salty soil-cement.It is suggested that replacement of 60% Portland cement by fly ash and GGBS,with the amount of GGBS not less than 40 %,can form an employable material,which is able to effectively prevent the deterioration of salty soil-cement.%通过室内试验,研究了黄河三角洲含盐水泥土的劣化规律以及粉煤灰和矿渣微粉对其劣化的抑制效应,并利用X射线衍射(XRD)和扫描电镜(SEM)对劣化机理及外加剂的改性机理进行了分析.结果表明:地下盐水环境对黄河三角洲水泥土有较强的腐蚀作用,其90,180 d龄期的抗压强度分别降低了18.5%,21.6%;掺加粉煤灰对黄河三角洲含盐水泥土的早期强度不利,但其后期强度会持续增加;掺加矿渣微粉对黄河三角洲含盐水泥土强度有明显的提升作用,并对其劣化有显著的抑制作用.为防止黄河三角洲含盐水泥土劣化,工程中建议用粉煤灰和矿渣微粉等质量替代60%的水泥,而且矿渣微粉掺量不少于40%.

  16. Effects of Irrigating with Treated Oil and Gas Product Water on Crop Biomass and Soil Permeability

    Energy Technology Data Exchange (ETDEWEB)

    Terry Brown; Jeffrey Morris; Patrick Richards; Joel Mason

    2010-09-30

    Demonstrating effective treatment technologies and beneficial uses for oil and gas produced water is essential for producers who must meet environmental standards and deal with high costs associated with produced water management. Proven, effective produced-water treatment technologies coupled with comprehensive data regarding blending ratios for productive long-term irrigation will improve the state-of-knowledge surrounding produced-water management. Effective produced-water management scenarios such as cost-effective treatment and irrigation will discourage discharge practices that result in legal battles between stakeholder entities. The goal of this work is to determine the optimal blending ratio required for irrigating crops with CBNG and conventional oil and gas produced water treated by ion exchange (IX), reverse osmosis (RO), or electro-dialysis reversal (EDR) in order to maintain the long term physical integrity of soils and to achieve normal crop production. The soils treated with CBNG produced water were characterized with significantly lower SAR values compared to those impacted with conventional oil and gas produced water. The CBNG produced water treated with RO at the 100% treatment level was significantly different from the untreated produced water, while the 25%, 50% and 75% water treatment levels were not significantly different from the untreated water. Conventional oil and gas produced water treated with EDR and RO showed comparable SAR results for the water treatment technologies. There was no significant difference between the 100% treated produced water and the control (river water). The EDR water treatment resulted with differences at each level of treatment, which were similar to RO treated conventional oil and gas water. The 100% treated water had SAR values significantly lower than the 75% and 50% treatments, which were similar (not significantly different). The results of the greenhouse irrigation study found the differences in biomass

  17. Inquiry on the application of cement-soil mixing pile in soft foundation%水泥土搅拌桩在软土地基中的应用与探讨

    Institute of Scientific and Technical Information of China (English)

    张谦

    2014-01-01

    分析了水泥加固软土的原理,主要阐述了水泥土搅拌桩在软土地基处理中的技术要求,并就预搅下沉钻杆、水泥浆拌制、喷浆搅拌等环节的注意事项作了研究,总结了一些水泥土搅拌桩常见质量问题的解决方法,以提高软基处理的技术水平。%The paper analyzes cement reinforcing soft soil principles,mainly describes the technological demands of cement-soil mixing pile in soft foundation treatment,studies subsidence drilling pile,cement mortar mixing,spraying grouting mixing and other matters,and summarizes common cement soil mixing problems solving methods,with a view to improve the soft foundation processing technology level.

  18. Cement Formation

    DEFF Research Database (Denmark)

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten;

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including......−liquid reactions are discussed, as are the influences of particles sizes on clinker phase formation. Furthermore, a mechanism for clinker phase formation in an industrial rotary kiln reactor is outlined....

  19. Research of the Influence of Cement Sneak into the Soil of Heavy Metals Zinc Interdiction Role%水泥潜入河道底泥对重金属锌阻截作用的研究

    Institute of Scientific and Technical Information of China (English)

    周长胜; 樊贵盛

    2015-01-01

    基于水泥随入渗污水潜入河床淤泥模拟试验,分析了水泥潜入对污水中重金属锌的阻截作用,揭示了污水所含重金属锌沿深度方向的变化特性。结果表明:水泥潜入河道淤泥可以有效阻截重金属锌在土壤中的纵向迁移;在一定范围内,土壤阻截重金属锌的作用随着水泥潜入量的增大而增大;在水泥潜入的条件下,重金属锌的表聚作用明显,即土壤阻截重金属锌的作用随深度的增大而减小。%Based on a series of tests on cement's infiltration into the simulated soil column together with infiltration wastewater,this paper an-alyzed the cement sneak carrying heavy metals in sewage interdiction role of zinc Zn,revealed the changing characteristics of wastewater con-taining heavy metals zinc along the depth. Tests show that the method of cement filters into the topsoil with seepage water can effectively pre-vent the migration of zinc in soils. At some extend,this retaining effect is amplified with the increase of cement volume while diminishes with the increase of soil column depth. Under the conditions of cement sneak,the function of heavy metals zinc sheet dimerization is more obvi-ous,i. e. it decreases sharply with increasing depth of soil column of Zn accumulation.

  20. State-of-the-art review of developments of laboratory tests on cemented calcareous soils%胶结钙质土的室内试验研究进展

    Institute of Scientific and Technical Information of China (English)

    朱长歧; 周斌; 刘海峰

    2015-01-01

    The naturally cemented calcareous soil is a carbonate soil or rock cemented by high-magnesium calcite or aragonite. It usually contains a large portion of coral and other tropical marine organism. Its unique engineering properties often result in troubles and difficulties in the geotechnical design and foundation construction. Its characteristics also attract research and experimental interests of many researchers. This paper presents state-of-the-art review of developments of the laboratory tests on both naturally and artificially cemented calcareous soils as well as the sample preparation techniques of artificially cemented soils. The general stress-strain behaviors of the cemented calcareous samples and factors that might affect its characteristics, such as confining pressure, initial sample density, and degree of cementation, are also summarized. The research work that could be improved is also proposed with an objective of providing a research guideline for the further studies of cemented calcareous soils.%天然胶结钙质土是广泛分布于热带及亚热带海洋中由生物碎屑经碳酸钙胶结或固结而形成的碳酸盐岩类。其独特的工程性质常常给岩土工程设计与施工带来麻烦,也正因此引起了研究者的兴趣并对其开展了较为全面的试验研究工作。针对天然胶结钙质土、人工胶结钙质土的室内试验以及人工胶结钙质土试样的制备等3方面取得的研究进展进行总结回顾,汇总了胶结钙质土的基本应力-应变行为以及围压、初始密度及胶结度等主要参数的影响规律,指出了研究中尚存在的问题,并对胶结钙质土的进一步的研究工作进行了展望。该工作必将对此领域的研究具有借鉴和指导意义。

  1. Resistência à compressão do solo-cimento com substituição parcial do cimento Portland por resíduo cerâmico moído Compressive strength of soil-cement with partial replacement of the Portland cement by crushed ceramic waste

    Directory of Open Access Journals (Sweden)

    Rivanildo Dallacort

    2002-12-01

    Full Text Available Neste trabalho, apresenta-se o estudo experimental da resistência à compressão do solo-cimento, com substituição parcial do cimento Portland por resíduo cerâmico moído. Para tanto, foram ensaiados 81 espécimenes cilíndricos desse material à compressão, em que parte do cimento foi substituída por material cerâmico moído. Realizou-se uma programação fatorial, na qual três variáveis foram selecionadas para estudo: o teor de material ligante (cimento + resíduo cerâmico, a umidade do solo e o teor de resíduo cerâmico adicionado. É apresentado um estudo estatístico através de análise de variância da massa específica do material e da resistência a compressão. Tal estudo permitiu concluir-se que substituições de 25 e 57% do teor de cimento por material cerâmico podem produzir blocos de solo-cimento com resistências superiores a 2 MPa, com teor de material ligante de 6 e 8%, respectivamente.In this paper, an experimental study of the compressive strength of soil-cement with partial replacement of the Portland cement by crushed ceramic waste is presented and discussed. For this, eighty-one cylindrical specimens of soil-cement were tested, where part of cement percentage was replaced by crushed ceramic waste. The experiment was conducted in factorial design and three variables were selected and studied: the binding material content (cement + ceramic waste, soil moisture content and the ratio of ceramic waste. A statistical study using variance analysis of the specific mass and compressive strength of the material is presented. This study concluded that replacement ratios of 25 and 57% of the Portland cement by crushed ceramic material can be used to fabricate soil-cement bricks with strength higher than 2 MPa, for a binding material content of 6 and 8% respectively.

  2. Consolidation behavior of cement-and lime/cement-mixed column foundations

    Institute of Scientific and Technical Information of China (English)

    蔡袁强; 徐长节

    2002-01-01

    The consolidation behavior of mixed in place cement- and lime/cement-mixed column was studied. Consolidation of the composite foundation was modeled as a three-dimensional axi-symmetric problem. The authors used the finite difference method to obtain the pore pressure variation with time at any location below the surface. A computer program developed by the authors was used to draw some interesting conclusions about the consolidation behaviors of cement- and lime/cement-mixed pile foundation. Finally, a combined model including the permeability coefficients of cement-mixed piles and soil, was studied and its feasibility was evaluated.

  3. Effect of strength enhancement of soil treated with environment-friendly calcium carbonate powder.

    Science.gov (United States)

    Park, Kyungho; Jun, Sangju; Kim, Daehyeon

    2014-01-01

    This study aims to investigate the effects of the strength improvement of soft ground (sand) by producing calcium carbonate powder through microbial reactions. To analyze the cementation effect of calcium carbonate produced through microbial reaction for different weight ratios, four different types of specimens (untreated, calcium carbonate, cement, and calcium carbonate + cement) with different weight ratios (2%, 4%, 6%, and 8%) were produced and cured for a period of 3 days, 7 days, 14 days, 21 days, and 28 days to test them. The uniaxial compression strength of specimens was measured, and the components in the specimen depending on the curing period were analyzed by means of XRD analysis. The result revealed that higher weight ratios and longer curing period contributed to increased strength of calcium carbonate, cement, and calcium carbonate + cement specimens. The calcium carbonate and the calcium carbonate + cement specimens in the same condition showed the tendency of decreased strength approximately 3 times and two times in comparison with the 8% cement specimens cured for 28 days, but the tendency of increased strength was approximately 4 times and 6 times in comparison with the untreated specimen. PMID:24688401

  4. Enhanced infiltration regime for treated-wastewater purification in soil aquifer treatment (SAT)

    Science.gov (United States)

    Nadav, Itamar; Arye, Gilboa; Tarchitzky, Jorge; Chen, Yona

    2012-02-01

    SummaryUtilization of treated wastewater (TWW) for agriculture is a widely accepted practice in regions suffering from freshwater (FW) shortages. Soil aquifer treatment is often employed for wastewater purification in regions with sandy soil. Infiltration rates of water through the soil can decrease as a result organic matter (OM) accumulation and the consequential water repellency. We examined several infiltration regimes with the aim of achieving lower levels of OM accumulation, reduced water repellency and increased infiltration rate in the topsoil layer of the infiltration basin. OM accumulation in the topsoil layer was found to be the main factor adversely affecting soil permeability. In measurements performed in the infiltration basins of the Tel Aviv wastewater-purification facility over a 1-year period, infiltration rates were found to differ with season, being low in the winter and high in the summer. Similar observations were made on small model infiltration ponds established to simulate the large basins. Several water-application regimes were tested for enhancement of the infiltration rates. Rapid application of TWW was the most efficient method in terms of reducing OM accumulation and water repellency in the topsoil layer. Low-rate, and spraying of TWW over the soil using sprinklers produced the highest OM accumulation and consequently, higher water repellency. Low-rate, single outlet application—the conventional infiltration method employed in the commercial infiltration basins—exhibited moderate OM accumulation and water repellency. Neither water repellency nor OM accumulation were observed in the FW-application regime. Accumulation of OM originating from the percolating TWW, at the topsoil layer was identified as dominating infiltration rate at the infiltration basins. Reduction of OM content by the means proposed and evaluated in this experiment can drastically increase infiltration rates.

  5. Impact of treated urban wastewater for reuse in agriculture on crop response and soil ecotoxicity.

    Science.gov (United States)

    Belhaj, Dalel; Jerbi, Bouthaina; Medhioub, Mounir; Zhou, John; Kallel, Monem; Ayadi, Habib

    2016-08-01

    The scarcity of freshwater resources is a serious problem in arid regions, such as Tunisia, and marginal quality water is gradually being used in agriculture. This study aims to study the impact of treated urban wastewater for reuse in agriculture on the health of soil and food crops. The key findings are that the effluents of Sfax wastewater treatment plant (WWTP) did not meet the relevant guidelines, therefore emitting a range of organic (e.g., up to 90 mg L(-1) COD and 30 mg L(-1) BOD5) and inorganic pollutants (e.g., up to 0.5 mg L(-1) Cu and 0.1 mg L(-1) Cd) in the receiving aquatic environments. Greenhouse experiments examining the effects of wastewater reuse on food plants such as tomato, lettuce, and radish showed that the treated effluent adversely affected plant growth, photosynthesis, and antioxidant enzyme contents. However, the pollution burden and biological effects on plants were substantially reduced by using a 50 % dilution of treated sewage effluent, suggesting the potential of reusing treated effluent in agriculture so long as appropriate monitoring and control is in place. PMID:26520100

  6. The assessment of treated wastewater quality and the effects of mid-term irrigation on soil physical and chemical properties (case study: Bandargaz-treated wastewater)

    Science.gov (United States)

    Kaboosi, Kami

    2016-05-01

    This study was conducted to investigate the characteristics of inflow and outflow wastewater of the Bandargaz wastewater treatment plant on the basis of the data collection of operation period and the samples taken during the study. Also the effects of mid-term use of the wastewater for irrigation (from 2005 to 2013) on soil physical and chemical characteristics were studied. For this purpose, 4 samples were taken from the inflow and outflow wastewater and 25 quality parameters were measured. Also, the four soil samples from a depth of 0-30 cm of two rice field irrigated with wastewater in the beginning and middle of the planting season and two samples from one adjacent rice field irrigated with fresh water were collected and their chemical and physical characteristics were determined. Average of electrical conductivity, total dissolved solids, sodium adsorption ratio, chemical oxygen demand and 5 days biochemical oxygen demand in treated wastewater were 1.35 dS/m, 707 ppm, 0.93, 80 ppm and 40 ppm, respectively. Results showed that although some restrictions exist about chlorine and bicarbonate, the treated wastewater is suitable for irrigation based on national and international standards and criteria. In comparison with fresh water, the mid-term use of wastewater caused a little increase of soil salinity. However, it did not lead to increase of soil salinity beyond rice salinity threshold. Also, there were no restrictions on soil in the aspect of salinity and sodium hazard on the basis of many irrigated soil classifications. In comparison with fresh water, the mid-term use of wastewater caused the increase of total N, absorbable P and absorbable K in soil due to high concentration of those elements in treated wastewater.

  7. Levoglucosan-assimilating bacteria was isolated from levoglucosan treated soil suspension

    Energy Technology Data Exchange (ETDEWEB)

    Xie, H.J. [Shandong Univ., Jinan (China). Environment Research Inst.; Chinese Academy of Sciencess, Beijing (China). Dept. of Environmental Biotechnology, Research Center for Eco-Environmental Sciences; Zhuang, X.L.; Bai, Z.H.; Zhang, H.X. [Chinese Academy of Sciencess, Beijing (China). Dept. of Environmental Biotechnology, Research Center for Eco-Environmental Sciences

    2008-07-01

    Levoglucosan (LG) is emitted into the environment only during the combustion of wood and cigarettes. As such, it is a useful tracer for wood smoke in the atmosphere. It also has potential use as a fermentative carbon and energy resource in the fermentation industry. Depending on the initial cellulose content of woody feedstocks, the yield of LG may range from 38 to 58 per cent. This study examined whether the LG-assimilating bacterium could be isolated or not under LG treatment. The study also addressed the impact of the LG on the genetic diversity and the diversity of the cultivable fraction of the bacterial community in soil suspension. Genetic diversity was analyzed by Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting. The changes in diversity were monitored by two different methods following a 90 day incubation period for 20 mg of LG per mL of soil suspension. The cultivable heterotrophic diversity was investigated by colony morphology on solid 1/5 lactobacillus medium. The results of the cultivable heterotrophic diversity and genetic diversity showed that there was an obvious decrease in diversity, and the amount of levoglucosan-assimilating bacteria also decreased. The application of LG had an obvious impact on Bacillus spp and Marinibacillus spp. Through cultivable analysis, five levoglucosan-assimilating bacteria were isolated from an LG treated soil suspension. Phylogenetic analysis of 16S rRNA gene sequences revealed that levoglucosan-assimilating bacteria belong to Bacillus and Marinibacillus. 2 refs., 2 tabs., 3 figs.

  8. Effect of biosurfactant[0] on the sorption of phenanthrene onto original and H2O2-treated soils

    Institute of Scientific and Technical Information of China (English)

    PEI Xiaohong; ZHAN Xinhua; ZHOU Lixiang

    2009-01-01

    The objective of this study was to examine the effect of biosurfactant on sorption of phenanthrene (PHE) onto the original or H2O2-treated black loamy soil (typic isohumisols) and red sandy soil (typic ferralisols). The sorption isotherms were performed with the original and "soft" carbon-removed soils in the presence and absence of biosurfactant (200 mg/L). The sorption and degradation of biosurfactant were investigated. The result showed that organic matter played an important role in PHE sorption onto the black loamy and red sandy soils, and the PHE sorption isotherms on the "soft" carbon-removed soils exhibited more nonlinearity than those on the original soils. The values of partition coefficient (Kd) on the original black loamy soil with or without 200 mg/L biosurfactant were 181.6 and 494.5 mL/g, respectively. Correspondingly, in the red sandy soil, Kd was 246.4 and 212.8 mL/g in the presence or absence of biosurfactant, respectively. The changes of Kd suggested that biosurfactant inhibited PHE sorption onto the black loamy soil, but facilitated PHE sorption onto the red sandy soil. The nonlinearity of PHE sorption isotherm was decreased in the presence of biosurfactant. Site specific sorption might occur during PHE sorption onto both the original and the "soft" carbon-removed soils in the presence of biosurfactant. It was noted that biosurfactant could also be sorbed onto soils. The maximal sorption capacity of the red sandy soil for biosurfactant was (76.9 ± 0.007) μg/g, which was 1.31 times that of black loamy soil. Biosurfactant was degraded quickly in the two selected soils, and 92% of biosurfactant were mineralized throughout the incubation experiment for 7 d. It implied that biosurfactant should be added frequently when the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils was conducted through PAH desorption approach facilitated by biosurfactant.

  9. An example of treated waste water use for soil irrigation in the SAFIR project.

    Science.gov (United States)

    Cary, L.; Jovanovic, Z.; Stikic, R.; Blagojevic, S.; Kloppmann, W.

    2009-04-01

    The safe use of treated domestic wastewater for irrigation needs to address the risks for humans (workers, exposed via contact with irrigation water, soil, crops and food, consumers, exposed via ingestion of fresh and processed food), for animals (via ingestion of crops on soil), for the crops and agricultural productivity (via salinity and trace element uptake), for soil (via accumulation or release of pollutants) as well as for surface, groundwaters and the associated ecosystems (via runoff and infiltration, Kass et al., 2005, Bouwer, 2000). In this context, the European FP6 SAFIR project (Safe and High Quality Food Production using Low Quality Waters and Improved Irrigation Systems and Management) investigates the geochemical quality of the root zone soil, knowing it is the main transit and storage compartment for pollutants. The type of reaction (sorption, co-precipitation…) and the reactive mineral phases also determine the availability of trace elements for the plant and determine the passage towards crops and products. Reactions of the infiltrating water with the soil solid phase are important for the solute cycling, temporary fixation and remobilisation of trace pollutants. Therefore the soil water quality was directly or indirectly assessed. Direct measurements of soil water were made through porous cups. The experiments were carried out during the growing season of 2006, 2007 and 2008 in a vegetable commercial farm, located at 10 km north of Belgrade. The soil is silty clayey, and developed on alluvial deposits. It was classified as humogley according to USDA Soil Classification. The climate of the field side is a continental type with hot and dry summers and cold and rainy winters. As in the rest of Serbia, farm suffers from water deficits during the main growing season. The initial soil quality was assessed through a sampling campaign before the onset of first year irrigation; the soil quality was then monitored throughout three years. Soil sampling

  10. An example of treated waste water use for soil irrigation in the SAFIR project.

    Science.gov (United States)

    Cary, L.; Jovanovic, Z.; Stikic, R.; Blagojevic, S.; Kloppmann, W.

    2009-04-01

    The safe use of treated domestic wastewater for irrigation needs to address the risks for humans (workers, exposed via contact with irrigation water, soil, crops and food, consumers, exposed via ingestion of fresh and processed food), for animals (via ingestion of crops on soil), for the crops and agricultural productivity (via salinity and trace element uptake), for soil (via accumulation or release of pollutants) as well as for surface, groundwaters and the associated ecosystems (via runoff and infiltration, Kass et al., 2005, Bouwer, 2000). In this context, the European FP6 SAFIR project (Safe and High Quality Food Production using Low Quality Waters and Improved Irrigation Systems and Management) investigates the geochemical quality of the root zone soil, knowing it is the main transit and storage compartment for pollutants. The type of reaction (sorption, co-precipitation…) and the reactive mineral phases also determine the availability of trace elements for the plant and determine the passage towards crops and products. Reactions of the infiltrating water with the soil solid phase are important for the solute cycling, temporary fixation and remobilisation of trace pollutants. Therefore the soil water quality was directly or indirectly assessed. Direct measurements of soil water were made through porous cups. The experiments were carried out during the growing season of 2006, 2007 and 2008 in a vegetable commercial farm, located at 10 km north of Belgrade. The soil is silty clayey, and developed on alluvial deposits. It was classified as humogley according to USDA Soil Classification. The climate of the field side is a continental type with hot and dry summers and cold and rainy winters. As in the rest of Serbia, farm suffers from water deficits during the main growing season. The initial soil quality was assessed through a sampling campaign before the onset of first year irrigation; the soil quality was then monitored throughout three years. Soil sampling

  11. INCORPORAÇÃO DE RESÍDUOS VEGETAIS E SEUS EFEITOS SOBRE AS CARACTERÍSTICAS FÍSICO-MECÂNICAS DE MISTURAS DE SOLO-CIMENTO PARA FINS DE CONSTRUÇÃO RURAL PLANT RESIDUES INCORPORATION EFFECTS ON PHYSICAL AND MECHANICAL CHARACTERISTICS OF SOIL-CEMENT MIXTURES FOR AGRICULTURAL BUILDINGS PURPOSES

    Directory of Open Access Journals (Sweden)

    Marcos Fernandes Oliveira

    2007-12-01

    Full Text Available

    O presente trabalho teve como objetivo avaliar o efeito da adição da casca de arroz e da casca da semente do capim braquiária, sobre as propriedades físico-mecânicas de misturas de solo-cimento e conseqüente análise de sua viabilidade técnica com vistas à fabricação de materiais de construção alternativos para fins rurais. Para tal, os resíduos foram triturados, peneirados e tratados em solução de cal e o solo submetido aos ensaios de caracterização segundo normas brasileiras. Os resíduos foram adicionados em substituição ao cimento, variando os teores de cimento e de resíduo vegetal desde 100% de cimento e 0% de resíduo, até 60% de cimento e 40% de resíduo. Posteriormente foram moldados corpos-de-prova cilíndricos que foram submetidos aos ensaios de compressão simples, aos sete, 28 e 56 dias, e de capacidade de absorção de água, aos sete dias da moldagem. Após análise dos resultados, pôde-se concluir que as misturas obtidas a partir da substituição parcial do cimento por 10% de resíduos mostram-se viáveis como matéria-prima na fabricação de elementos construtivos não estruturais, tais como, blocos e tijolos prensados, destinados às construções e instalações rurais.

    PALAVRAS-CHAVE: Solo-cimento, resíduos vegetais, construções rurais.

    The aim of this research was to evaluate the effect of rice and Brachiaria brizantha husks on physical and mechanical properties of soil-cement mixtures and, consequently, to analyse their technical feasibility to manufacture alternative building materials for agricultural purposes. Husks were ground, sieved, and treated in lime solution and soil submitted to characterisation tests according to Brazilian standards. The plant residues were added in substitution to the cement. The cement content and

  12. Research on the Application of Cement-soil Arched Walls in the Anti-slide Reinforcement of Soft Ground Embankment%水泥土连拱抗滑墙加固软基边坡的应用研究

    Institute of Scientific and Technical Information of China (English)

    仲曼; 蒋红俊; 梁音; 李琴琴

    2014-01-01

    软基边坡处理中常采用水泥土搅拌桩复合地基。但受水平推力作用时桩体存在弯折效应且施工时易出现劣质层。本文采用水泥土连拱抗滑墙加固软基边坡,采用数值分析的方法建立三维模型,分析加固前后边坡的水平侧移、沉降、应力、边坡稳定性的变化,并深入的分析了连拱抗滑墙抗滑机理。研究表明连拱抗滑墙加固边坡技术具有性能可靠、施工方便的优势,在软基边坡加固领域具有广阔的应用前景。%In the soft subsoil of slope,soil cement piles will bear lateral forces from slope sliding potential,which will cause pile crack because of poor tension strength of soil cement.A new structure of cement-soil mixing pile is raised to improve the anti-slide reinforcement of soft ground embankment.The numerical simulation method is employed to ana-lyze the structure by the dimensional models.Referring to the analysis of the results,displacement,settlement,stress, slope stability conditions after reinforcement.The cement-soil arched walls could make well performance and convenient construction.There is a great application prospect in fields of soft ground slope reinforcement.

  13. Preliminary Systems Design Study assessment report. [Evaluation of using specific technologies, system concepts for treating the buried waste and the surrounding contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Mayberry, J.L.; Feizollahi, F.; Del Signore, J.C.

    1992-01-01

    The System Design Study (SDS), part of the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examined techniques available for the remediation of hazardous and transuranic waste stored at the Radioactive Waste Management Complex's Subsurface Disposal Area at the INEL. Using specific technologies, system concepts for treating the buried waste and the surrounding contaminated soil were evaluated. Evaluation included implementability, effectiveness, and cost. The SDS resulted in the development of technology requirements including demonstration, testing, and evaluation activities needed for implementing each concept. This volume of the Systems Design Study contain four Appendixes that were part of the study. Appendix A is an EG G Idaho, Inc., report that represents a review and compilation of previous reports describing the wastes and quantities disposed in the Subsurface Disposal Area of the Idaho National Engineering Laboratory. Appendix B contains the process flowsheets considered in this study, but not selected for detailed analysis. Appendix C is a historical tabulation of radioactive waste incinerators. Appendix D lists Department of Energy facilities where cementation stabilization systems have been used.

  14. Compressibility Behavior of Tropical Peat Reinforced with Cement Columns

    OpenAIRE

    Youventharan Duraisamy; Bujang B.K. Huat; Azlan A. Aziz

    2007-01-01

    This paper presents the compressibility of tropical peat reinforced with cylindrical cement columns. When a cement column is installed vertically in peat, its com-pressibility is reduced because of the hardened skeleton matrix formed by cement parti-cles bonding with adjacent soil particles in the presence of pore water. The effects of the cement column diameter on the compressibility have been investigated in this study. The results indicated that compressibility index Cc and Cα decreas...

  15. Effects of Pseudomonas species on the release of bound 14C residues from soil treated with [14C]atrazine

    International Nuclear Information System (INIS)

    The release of bound (nonextractable) 14C residues from soil previously treated with [14C]atrazine was investigated by incubation of the solvent-extracted soil with two species of Pseudomonas capable of metabolizing atrazine. The two species, 192 and 194, released bound 14C residues from the soil. Addition of glucose, known to increase microbiological activities, to the incubated soil appeared to enhance the release of soil-bound 14C residues, in particular in the presence of Pseudomonas species 192. The 14C bound residues in soil, mainly present as the parent compound and its hydroxy and monodealkylated analogues, were released into the incubation mixture and were subsequently metabolized by the two species involving dechlorination and dealkylation

  16. Experimental study on enhancing bearing capacity of marine soft soil foundation with cement-mixing piles%水泥土搅拌桩增强海相软土地基承载力的试验研究

    Institute of Scientific and Technical Information of China (English)

    吕田丰

    2015-01-01

    为了研究本地区海相软土地基采用水泥土搅拌桩进行加固技术,提高海相软土地基承载力的可行性。选取了本地区典型的海相软土场地,采用水泥土搅拌桩对软土地基进行加固,利用浅层平板载荷试验和复合地基载荷试验的方法,对海相软土加固前后的地基承载能力进行了比较分析。结果表明,利用水泥土搅拌桩对海相软土地基进行加固,可以有效地增强海相软土地基承载力。%In order to study the feasibility of improving bearing capacity of marine soft soil foundation through the technique of reinforcing local marine soft soil foundation with cement-mixing piles,we select typical marine soft soil site and reinforce the soft soil foundation with cement-mixing piles.Through super-ficial plate loading test and composite foundation loading test,we conduct comparative analysis on the bear-ing capacities of marine soft soil foundation before and after the reinforcement.Results show that reinfor-cing marine soft soil foundation with cement-mixing piles can improve the bearing capacity effectively.

  17. Treated wastewater irrigation effect on soil,crop and environment: Wastewater recycling in the loess area of China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A study was carried out at the Loess Plateau in Dongzhi,China,to test the feasibility of using secondary treatment sewage effluent and to determine whether the water quality would then meet the recommended irrigation norm.Seven crops,including celery,wheat,maize,millet,apples,rapeseed and yellow beans,were tested in the study.Physical and chemical properties of the soil,crop yield and quality and leachate at different soil depths were measured.In most cases,the quality of the crops that made use of treated sewage was not distinctively different from those that did not use treated sewage.However,yields for the former were much higher than they were for the latter.Leachates at different soil depths were analyzed and the results did not show alarming levels of constituents.For a period of approximately 14 months.the treated sewage irrigation had no significant effect on the loess soil and no cases of illness resulting from contact with the treated sewage were reported.With treated sewage irrigation,a slight increase in the organic content of the soil was observed.

  18. Soil Loss by Wind Erosion for Three Different Textured Soils Treated with Polyacrylamide and Crude Oil, Iraq

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The study is conducted to estimate the resistance of three soils (EL-Hartha clay loam, Barjisiya sandy loam and the soil near the sand dunes in Sheikh sa'ad area sandy soil) to wind erosion, it is also aimed at getting full acquaintance of the relationship between the soil loss and the physical and chemical features of soil. In addition to the experiment of some soil stabilizers, polyacrylamide (PAM) concentration of 0.2 % and crude oil in concentration of 1 % in order to reduce or prevent wind erosion. The study shows that the amendment increased the dry soil aggregate >1 mm, mean weight diameter and soil moisture. It is clear that polyacrylamide had greater effect than that of crude oil, besides the great effectiveness of these amendments in decreasing bulk density and relations of soil loss.

  19. Efficiency of Micro-fine Cement Grouting in Liquefiable Sand

    International Nuclear Information System (INIS)

    In the presence of strong ground motion, liquefaction hazards are likely to occur in saturated cohesion-less soils. The risk of liquefaction and subsequent deformation can be reduced by various ground improvement methods including the cement grouting technique. The grouting method was proposed for non-disruptive mitigation of liquefaction risk at developed sites susceptible to liquefaction. In this research, a large-scale experiment was developed for assessment of micro-fine cement grouting effect on strength behavior and liquefaction potential of loose sand. Loose sand samples treated with micro-fine grout in multidirectional experimental model, were tested under cyclic and monotonic triaxial loading to investigate the influence of micro-fine grout on the deformation properties and pore pressure response. The behavior of pure sand was compared with the behavior of sand grouted with a micro-fine cement grout. The test results were shown that cement grouting with low concentrations significantly decreased the liquefaction potential of loose sand and related ground deformation

  20. Stability of embankments over cement deep soil mixing columns; Estabilidad de terraplenes sobre columnas de suelo-cemento

    Energy Technology Data Exchange (ETDEWEB)

    Morilla Moar, P.; Melentijevic, S.

    2014-07-01

    The deep soil mixing (DSM) is one of the ground improvement methods used for the construction of embankments over soft soils. DSM column-supported embankments are constructed over soft soils to accelerate its construction, improve embankment stability, increase bearing capacity and control of total and differential settlements. There are two traditional design methods, the Japanese (rigid columns) and the scandinavian (soft and semi-rigid columns). Based on Laboratory analysis and numerical analysis these traditional approaches have been questioned by several authors due to its overestimation of the embankment stability considering that the most common failures types are not assumed. This paper presents a brief review of traditional design methods for embankments on DSM columns constructed in soft soils, studies carried out determine the most likely failure types of DSM columns, methods to decrease the overestimation when using limit equilibrium methods and numerical analysis methods that permit detect appropriate failure modes in DSM columns. Finally a case study was assessed using both limited equilibrium and finite element methods which confirmed the overestimation in the factors of safety on embankment stability over DSM columns. (Author)

  1. Impact of treated wastewater on growth, respiration and hydraulic conductivity of citrus root systems in light and heavy soils.

    Science.gov (United States)

    Paudel, Indira; Cohen, Shabtai; Shaviv, Avi; Bar-Tal, Asher; Bernstein, Nirit; Heuer, Bruria; Ephrath, Jhonathan

    2016-06-01

    Roots interact with soil properties and irrigation water quality leading to changes in root growth, structure and function. We studied these interactions in an orchard and in lysimeters with clay and sandy loam soils. Minirhizotron imaging and manual sampling showed that root growth was three times lower in the clay relative to sandy loam soil. Treated wastewater (TWW) led to a large reduction in root growth with clay (45-55%) but not with sandy loam soil (hydraulic conductivity was severely reduced in clay soil. Treated wastewater increased respiration rate and reduced hydraulic conductivity of all root orders in clay but only of the lower root orders in sandy loam soil. Loss of hydraulic conductivity increased with root order in clay and clay irrigated with TWW. Respiration and hydraulic properties of all root orders were significantly affected by sodium-amended TWW in sandy loam soil. These changes in root order morphology, anatomy, physiology and hydraulic properties indicate rapid and major modifications of root systems in response to differences in soil type and water quality.

  2. Impact of treated wastewater on growth, respiration and hydraulic conductivity of citrus root systems in light and heavy soils.

    Science.gov (United States)

    Paudel, Indira; Cohen, Shabtai; Shaviv, Avi; Bar-Tal, Asher; Bernstein, Nirit; Heuer, Bruria; Ephrath, Jhonathan

    2016-06-01

    Roots interact with soil properties and irrigation water quality leading to changes in root growth, structure and function. We studied these interactions in an orchard and in lysimeters with clay and sandy loam soils. Minirhizotron imaging and manual sampling showed that root growth was three times lower in the clay relative to sandy loam soil. Treated wastewater (TWW) led to a large reduction in root growth with clay (45-55%) but not with sandy loam soil (hydraulic conductivity was severely reduced in clay soil. Treated wastewater increased respiration rate and reduced hydraulic conductivity of all root orders in clay but only of the lower root orders in sandy loam soil. Loss of hydraulic conductivity increased with root order in clay and clay irrigated with TWW. Respiration and hydraulic properties of all root orders were significantly affected by sodium-amended TWW in sandy loam soil. These changes in root order morphology, anatomy, physiology and hydraulic properties indicate rapid and major modifications of root systems in response to differences in soil type and water quality. PMID:27022106

  3. Settlement Control of Soft Ground using Cement-Ricehusk Stabilization

    Directory of Open Access Journals (Sweden)

    Mokhtar M.

    2012-01-01

    Full Text Available Cement is widely used for improvement of soft soils, but financial and environmental concerns are causing genuine concerns to all parties, leading to the quest for alternative and effective stabilizers. Ricehusk is an agricultural waste in Malaysia, commonly disposed of by open burning or dumping in landfills. Considering that the ashes derived from ricehusk are pozzolanic in nature, there is a possibility that a cement-ricehusk mixture could effectively improve soft soils with reduced cement dosage. This study examines the mixture’s effectiveness by monitoring the settlement reduction in a clay soil. Standard oedometer tests were carried out on a soft marine clay sample admixed with cement-ricehusk. Test specimens contained 0-10% cement and 0-5% of ricehusk respectively, and were left to cure for either seven or 28 days. The stabilized specimens were observed to undergo significant reduction in compressibility, verifying the potential of cement-ricehusk as an alternative soft soil stabilizer.

  4. Impact of use of treated wastewater for irrigation on soil and quinoa crop in South of Morocco

    Science.gov (United States)

    El Youssfi, Lahcen; Choukr-Allah, Redouane; Zaafrani, Mina; Hirich, Aziz; Fahmi, Hasna; Abdelatif, Rami; Laajaj, Khadija; El Omari, Halima

    2015-04-01

    This work was conducted at the experimental station of the IAV Hassan II-CHA-Agadir in southwest Morocco between 2010 and 2012. It aimed the assessment of the effects of use of treated wastewater on soil properties and agronomic parameters by adopting crop rotation introducing quinoa (Chenopodium quinoa Willd.) as a new crop under semi-arid climate. Biomass production, yield, nutrient accumulation in leaves and the level of electrical conductivity and soil nitrate are the evaluated parameters during three growing seasons. Results show that quinoa has a performing behavior when it is preceded by fabae bean in term of water use efficiency; in addition, the recorded level of salt accumulation in the soil was the lowest in comparison with that of the combinations bean>quinoa and fallow>quinoa. Concerning growth and yield, it was found that growing quinoa after chickpea was more beneficial in terms of biomass productivity and yield. Keywords: Quinoa, soil, treated wastewater semi-arid

  5. Occurrence and distribution of PAHs, PCBs, and chlorinated pesticides in Tunisian soil irrigated with treated wastewater.

    Science.gov (United States)

    Haddaoui, Imen; Mahjoub, Olfa; Mahjoub, Borhane; Boujelben, Abdelhamid; Di Bella, Giuseppa

    2016-03-01

    Treated wastewater (TWW) is a well recognized source of organic pollutants (OPs) that may accumulate during irrigation. For the first time, data on the occurrence of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyles (PCBs) and organochlorinated pesticides (OCPs) in wastewater irrigated soil in Nabeul (Tunisia) are reported. 13 PAHs, 18 PCBs and 16 OCPs were analyzed in soil samples collected at 0-10 and 10-20 cm depth before each and every irrigation and after the irrigation period expanding from June to October. Soil was extracted with an accelerated solvent extractor and analyzed by a tandem gas chromatograph in selected reaction monitoring mode (GC/MS/MS/SRM). OPs residues were detected before irrigation and accumulated at the end of the season for some of them. The total concentration of PAHs varied between 120.01 and 365.18 μg kg(-1) dry weight (dw) at 0-10 cm depth before and at the end of irrigation, respectively. The total concentration of PCBs varied between 11.26 and 21.89 μg kg(-1) dw at 0-10 cm, being higher than those reported for 10-20 cm. The six indicator PCB congeners (28, 52, 101, 138, 153, 180) were predominant. OCPs concentrations ranged between 12.49 and 21.81 μg kg(-1) at 0-10 cm and between 74.03 and 310.54 μg kg(-1) at 10-20 cm depth. DDT was predominant accounting for more than 94% of the total OCPs. In view of the present results, OPs are relevant to the agricultural environment, calling for more research on their persistence and potential transfer to plants and/or groundwater while taking into account farmers' practices.

  6. Occurrence and distribution of PAHs, PCBs, and chlorinated pesticides in Tunisian soil irrigated with treated wastewater.

    Science.gov (United States)

    Haddaoui, Imen; Mahjoub, Olfa; Mahjoub, Borhane; Boujelben, Abdelhamid; Di Bella, Giuseppa

    2016-03-01

    Treated wastewater (TWW) is a well recognized source of organic pollutants (OPs) that may accumulate during irrigation. For the first time, data on the occurrence of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyles (PCBs) and organochlorinated pesticides (OCPs) in wastewater irrigated soil in Nabeul (Tunisia) are reported. 13 PAHs, 18 PCBs and 16 OCPs were analyzed in soil samples collected at 0-10 and 10-20 cm depth before each and every irrigation and after the irrigation period expanding from June to October. Soil was extracted with an accelerated solvent extractor and analyzed by a tandem gas chromatograph in selected reaction monitoring mode (GC/MS/MS/SRM). OPs residues were detected before irrigation and accumulated at the end of the season for some of them. The total concentration of PAHs varied between 120.01 and 365.18 μg kg(-1) dry weight (dw) at 0-10 cm depth before and at the end of irrigation, respectively. The total concentration of PCBs varied between 11.26 and 21.89 μg kg(-1) dw at 0-10 cm, being higher than those reported for 10-20 cm. The six indicator PCB congeners (28, 52, 101, 138, 153, 180) were predominant. OCPs concentrations ranged between 12.49 and 21.81 μg kg(-1) at 0-10 cm and between 74.03 and 310.54 μg kg(-1) at 10-20 cm depth. DDT was predominant accounting for more than 94% of the total OCPs. In view of the present results, OPs are relevant to the agricultural environment, calling for more research on their persistence and potential transfer to plants and/or groundwater while taking into account farmers' practices. PMID:26716883

  7. Heavy metal input to agricultural soils from irrigation with treated wastewater: Insight from Pb isotopes

    Science.gov (United States)

    Kloppmann, Wolfram; Cary, Lise; Psarras, Georgios; Surdyk, Nicolas; Chartzoulakis, Kostas; Pettenati, Marie; Maton, Laure

    2010-05-01

    A major objective of the EU FP6 project SAFIR was to overcome certain drawbacks of wastewater reuse through the development of a new irrigation technology combining small-scale modular water treatment plants on farm level and improved irrigation hardware, in the aim to lower the risks related to low quality water and to increase water use efficiency. This innovative technology was tested in several hydro-climatic contexts (Crete, Italy, Serbia, China) on experimental irrigated tomato and potato fields. Here we present the heavy metal variations in soil after medium-term (3 irrigation seasons from 2006-2008) use of treated municipal wastewater with a special focus on lead and lead isotope signatures. The experimental site is located in Chania, Crete. A matrix of plots were irrigated, combining different water qualities (secondary, primary treated wastewater, tap water, partially spiked with heavy metals, going through newly developed tertiary treatment systems) with different irrigation strategies (surface and subsurface drip irrigation combined with full irrigation and partial root drying). In order to assess small scale heavy metal distribution around a drip emitter, Pb isotope tracing was used, combined with selective extraction. The sampling for Pb isotope fingerprinting was performed after the 3rd season of ww-irrigation on a lateral profile from a drip irrigator (half distance between drip lines, i.e. 50cm) and three depth intervals (0-10, 10-20, 20-40 cm). These samples were lixiviated through a 3 step selective extraction procedure giving rise to the bio-accessible, mobile and residual fraction: CaCl2/NaNO3 (bio-accessible fraction), DPTA (mobile fraction), total acid attack (residual fraction). Those samples were analysed for trace elements (including heavy metals) and major inorganic compounds by ICP-MS. The extracted fractions were then analysed by Thermal Ionisation Mass Spectrometry (TIMS) for their lead isotope fingerprints (204Pb, 206Pb, 207Pb, 208Pb

  8. Leaf structural traits of tropical woody species resistant to cement dust.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Paiva, Elder Antonio Sousa

    2016-08-01

    Cement industries located nearby limestone outcrops in Brazil have contributed to the coating of cement dust over native plant species. However, little is known about the extent of the response of tropical woody plants to such environmental pollutant particularly during the first stages of plant development and establishment. This work focused on the investigation of possible alterations in leaf structural and ultrastructural traits of 5-month-old Guazuma ulmifolia Lam. (Malvaceae), 6-month-old Myracrodruon urundeuva Allemão (Anacardiaceae), and 9-month-old Trichilia hirta L. (Meliaceae) challenged superficially with cement dust during new leaf development. Leaf surface of plants, the soil or both (leaf plus soil), were treated (or not) for 60 days, under controlled conditions, with cement dust at 2.5 or 5.0 mg cm(-2). After exposure, no significant structural changes were observed in plant leaves. Also, no plant death was recorded by the end of the experiment. There was also some evidence of localized leaf necrosis in G. ulmifolia and T. hirta, leaf curling in M. urundeuva and T. hirta, and bulges formation on epidermal surface of T. hirta, after cement dust contact with plant shoots. All species studied exhibited stomata obliteration while T. hirta, in particular, presented early leaf abscission, changes in cellular relief, and organization and content of midrib cells. No significant ultrastructural alterations were detected under the experimental conditions studied. Indeed, mesophyll cells presented plastids with intact membrane systems. The high plant survival rates, together with mild morphoanatomic traits alterations in leaves, indicate that G. ulmifolia is more resistant to cement dust pollutant, followed by M. urundeuva and T. hirta. Thus, the three plant species are promising for being used to revegetate areas impacted by cement industries activities. PMID:27146683

  9. 利用熟石灰改善水泥固化土早期强度的试验研究%Experimental Study on properties of Early Strength of lime-cement soil

    Institute of Scientific and Technical Information of China (English)

    解国梁; 解恒燕; 郑鑫

    2013-01-01

    以内蒙古河套地区粉质粘土为研究对象,在水泥掺量一定的情况下,将熟石灰作为水泥土的外掺剂,通过室内无侧限抗压强度试验,探讨熟石灰掺量、龄期对水泥土早期无侧限抗压强度的影响规律。试验研究表明:在熟石灰的参与下,水泥土中存在火山灰作用和离子交换作用,但是作用效果较小,从而证明水化作用是水泥土强度的最主要来源。结合试验粘土特性和水泥土强度增长规律提出粘土中粘土矿物数量不足限制了火山灰作用和离子交换作用,超量熟石灰对水泥土强度基本没有影响。%Silty clay of irrigation district was selected for study in Hetao,Inner Mongolia. Slaked lime was used as admixture of cement and soil in the case of certain cement content,and the influence factors of dosage and the age of cement soil was analyzed according to the unconfined compressive strength experiment.The results showed that the cement soil had pozzolanic effect and ion-exchange action under the participation of slaked lime,but the degree of effects was low. So hydration was the most important source of strength. Combined with characteristic of clay and strength growth regulation,the pozzolanic effect and ion-exchange action was limited with insufficient clay minerals and impact of excess calcium hydroxide to cemented-soil strength was very small.

  10. Method for testing porosity of gelled cement slurry based on soil science%基于土壤学的胶凝态水泥浆孔隙度测试方法

    Institute of Scientific and Technical Information of China (English)

    李早元; 李进; 刘健; 董广超; 张凯; 郭小阳

    2015-01-01

    The porosity of gelled cement slurry is one of the important parameters in evaluating the gelling performance in the process of cement slurry gelling. This article compared and analyzed the gelled cement slurry and soil in macro and micro scales by means of qualitative analysis and experimental demonstration, and the result shows that these two have similar‘framework-pore structure’, both showing certain porosity and permeability. Therefore, by introducing the method of soil porosity testing in soil science, and combining the hydration properties of gelled cement slurry, the drying method in the soil porosity test principle is changed to freeze drying by liquid nitrogen, vacuum negative pressure drying or heated and dried after hydration is terminated by soaking in absolute ethyl alcohol which can inhibit hydration. And research was conducted on the porosity of slurry at speciifc hydration time, which provides reference for detection of porosity of cement slurry.%胶凝态水泥浆孔隙度是水泥浆凝结过程中评价胶凝态性能的重要参数之一。通过定性分析、实验验证的方法,对胶凝态水泥浆和土壤进行了宏观及微观等对比分析,两者具有相类似的“骨架-孔隙结构”,均表现出一定的孔隙性和渗透性。因此,引入土壤学中土壤孔隙度测试方法,同时结合胶凝态水泥浆的水化特性,将土壤孔隙度测试原理中烘干方式改进为液氮冷冻干燥、真空负压干燥或用无水乙醇浸泡终止水化后再升温干燥等可抑制水化反应的烘干方式。应用该方法对特定水化时间下的浆体开展了孔隙度探索实验,为检测水泥浆体的孔隙度提供了可借鉴的方法。

  11. Lead behavior in soil treated with contaminated sewage sludge and cultivated with maize

    Directory of Open Access Journals (Sweden)

    Marcilene Ferrari Barriquelo

    2003-12-01

    Full Text Available Lead (Pb behavior was studied in soil treated twice with sewage sludge contaminated with lead at interval of 18 months. Soil samples received five different treatments: three with lead [0 (reference; 2,500; 5,000 mug g-1] and two with a mixture of lead and cadmium (interferer (2,500 + 2,500 and 5,000 + 5,000 mug g-1, respectively. Vases containing treated soil were cultivated with maize in a greenhouse for 75 days. Pb was extracted using nitric perchloric digestion and analyzed by atomic absorption spectroscopy. The soil, containing sewage sludge contaminated by lead presented a higher concentration of Pb. The metal concentration remained constant in all treatments at 20-60 cm depth. No absorption of Pb by the plants was detected.O comportamento do Pb foi estudado num Latossolo Vermelho Escuro tratado com lodo de esgoto (biossólido contaminado, 18 meses após o tratamento do mesmo. As amostras de solo coletadas num perfil de 0 a 80 cm de profundidade foram dispostas da mesma forma em tubos de PVC (80 cm de altura e 10 cm de diâmetro em triplicata, os quais tinham lateral e diametralmente opostos, a cada 10 cm de profundidade a partir dos 20 cm da superfície, tubos sonda contendo o mesmo solo do interior do tubo de PVC. As frações de solo de 0 a 20 cm de cada tubo, receberam 5 tratamentos: três concentrações de chumbo: 0,0 (referência; 2.500; 5.000 mig g-1 e duas com a mistura de chumbo e cádmio (como interferente nas seguintes proporções: 2.500 : 2.500 e 5.000 : 5.000 mig g-1, respectivamente. Nos tubos com o solo contaminado, em casa de vegetação, foi cultivado o milho como planta teste, durante 75 dias. Após, as plantas, os solos tratados (0 a 20 cm e os solos dos tubos sonda foram coletados, preparados e digeridos com ácido nítrico e perclórico. As concentrações de Pb foram obtidas pelo método da espectrometria de absorção atômica. As amostras de solo da camada de 0-20 cm foram as que apresentaram as maiores

  12. Tympanoplasty with ionomeric cement.

    Science.gov (United States)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    Patients with isolated erosion of the long incus process suffer from severe hearing loss caused by lack of continuity of the ossicular chain. This study is a retrospective evaluation of the hearing results using two different surgical procedures. Since January 1993, 12 consecutive patients with isolated erosion of the long incus process have been treated with a new surgical technique in which the ossicular chain was rebuilt with ionomeric cement. The results in hearing performance (mean pure-tone average (PTA) 0.5, 1 and 2 kHz) were evaluated pre- and post-surgery, and compared to those in a group of 20 historical controls who underwent surgery in 1991 and 1992 using incus autograft interposition. Among the 12 index patients, 7 (58%) achieved improvement in PTA of > 10 dB, in 3 there was no difference and in 2 a slight decline. Among the 20 controls, 14 (70%) achieved improvement in PTA of > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy to perform, presents less risk of damage to the stapes and cochlea, requires less extensive surgery and does not exclude other surgical methods in cases of reoperation. PMID:10909000

  13. Silicon powder-experimental study on the influence of the fly ash to the strength of cement-soil%双掺粉煤灰硅粉对水泥土抗压强度影响试验研究

    Institute of Scientific and Technical Information of China (English)

    李俊哲; 方光秀

    2016-01-01

    以吉林省延吉市砂土作为研究对象,对双掺硅粉—粉煤灰水泥土进行了无侧限抗压强度试验,分析不同粉煤灰、硅粉掺量以及各龄期对硅粉—粉煤灰水泥土抗压强度的影响,结果表明:随粉煤灰与硅粉掺量的增加,水泥土后期强度基本呈增大趋势,随着粉煤灰掺量的增加,早期抗压强度逐渐减小,后期抗压强度则明显提高,掺硅粉不仅显著改善水泥土早期抗压强度,且明显提高其后期抗压强度。%Taking the sand in Yanji city as the research object,we made an unconfined compressive strength test on the silica fume and fly ash cement. We studied on the effect of silica fume and fly ash cement compressive strength when it was mixed with different amount of fly ash and silica fume. The results showed that:the cement soil strength showed a trend of increase with the increase of fly ash and fume content,in the ear-ly stage,with the content of fly ash increasing,the comprehensive strength decreases gradually,but in the latter stage,it is obviously improved, silica fume can not only significantly improve the early strength of cement soil but also make great influence on the later strength.

  14. Nitrous Oxide Fluxes, Soil Oxygen, and Dentrification Potential from Urine and Non-urine Treated Soil Under Different Irrigation Frequencies

    Science.gov (United States)

    Despite increased use of irrigation to improve forage quality and quantity for grazing cattle (Bos taurus), few studies have assessed how irrigation practices influence nitrous oxide (N2O) emissions from urine-impacted soils. In particular, irrigation effects on soil oxygen (O2) availability, one of...

  15. Changes in metal speciation and pH in olive processing waste and sulphur-treated contaminated soil.

    Science.gov (United States)

    de la Fuente, C; Clemente, R; Bernal, M P

    2008-06-01

    Degradation of organic matter from olive mill waste and changes in the heavy metal fractionation of a metal-contaminated calcareous soil were studied in a laboratory experiment, in which the olive mill waste was mixed with the soil and then incubated under aerobic conditions. The soil was calcareous (15% CaCO(3)) with high Zn and Pb concentrations (2058 and 2947 mg kg(-1), respectively). The organic amendment was applied at a rate equivalent to 20 g kg(-1) soil, and unamended soil was run as a control. To discern if changes in metal solubility were due to the acidic character of the waste, elemental sulphur was applied to soil as a non-organic acidifying material. The S(0) rates used were 3.14, 4.71 and 6.28 g kg(-1). The mineralisation of total organic-C (TOC) from the waste reached 14.8% of the original TOC concentration after 56 days of incubation. The CO(2)-C produced from S(0)-treated soils showed the carbonate destruction by the H(2)SO(4) formed through S(0) oxidation. The organic waste increased EDTA-extractable Zn and Pb concentrations and CaCl(2)-extractable Mn levels in soil after two days of incubation. The changes in metal availability with time indicated that the oxidation of phenols from the waste reduced Mn (IV) oxides, releasing Zn and Pb associated with this mineral phase. Organic waste addition did not decrease soil pH; the acidifying effect of S(0) did not change metal fractionation in the soil. PMID:17659778

  16. C and N accumulations in soil aggregates determine nitrous oxide emissions from cover crop treated rice paddy soils during fallow season

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Prabhat, E-mail: prabhat2003@gmail.com; Haque, Md. Mozammel; Kim, Sang Yoon; Kim, Pil Joo, E-mail: pjkim@gnu.ac.kr

    2014-08-15

    Combination of leguminous and non-leguminous plant residues are preferably applied in rice paddy soils to increase the rate of organic matter mineralization and to improve plant growth. However, organic matter addition facilitates methane (CH{sub 4}) emission from rice paddy soil. Mineralization of organic nitrogen (N) increases NO{sub 3}–N concentrations in soil, which are precursors for the formation of nitrous oxide (N{sub 2}O). However, N{sub 2}O is a minor greenhouse gas emitted from submerged rice field and hence is not often considered during calculation of total global warming potential (GWP) during rice cultivation. The hypothesis of this study was that fluxes of N{sub 2}O emissions might be changed after removal of flooded water from rice field and the effect of cover crops on N{sub 2}O emissions in the fallow season might be interesting. However, the effects of N-rich plant residues on N{sub 2}O emission rates in the fallow season and its effect on annual GWP were not studied before. In this experiment, combination of barley (non-leguminous) and hairy vetch (leguminous) biomasses were applied at 9 Mg ha{sup −1} and 27 Mg ha{sup −1} rates in rice paddy soil. Cover crop application significantly increased CH{sub 4} emission flux while decreased N{sub 2}O emissions during rice cultivation. The lowest N{sub 2}O emission was observed in 27 Mg ha{sup −1} cover crop treated plots. Cover crop applications increased N contents in soil aggregates especially in smaller aggregates (< 250 μm), and that proportionately increased the N{sub 2}O emission potentials of these soil aggregates. Fluxes of N{sub 2}O emissions in the fallow season were influenced by the N{sub 2}O emission potentials of soil aggregates and followed opposite trends as those observed during rice cultivation. Therefore, it could be concluded that the doses of cover crop applications for rice cultivation should not be optimized considering only CH{sub 4}, but N{sub 2}O should also be

  17. Nitrous Oxide Fluxes, Soil Oxygen, and Denitrification Potential of Urine- and Non-Urine-Treated Soil under Different Irrigation Frequencies.

    Science.gov (United States)

    Owens, Jen; Clough, Tim J; Laubach, Johannes; Hunt, John E; Venterea, Rodney T; Phillips, Rebecca L

    2016-07-01

    Despite increased use of irrigation to improve forage quality and quantity for grazing cattle ( Linnaeus), there is a lack of data that assess how irrigation practices influence nitrous oxide (NO) emissions from urine-affected soils. Irrigation effects on soil oxygen (O) availability, a primary controller of NO fluxes, is poorly understood. It was hypothesized that increased irrigation frequency would result in lower NO emissions by increasing soil moisture and decreasing soil O concentrations. This would favor more NO reduction to dinitrogen (N). We examined effects of high (3-d) versus low (6-d) irrigation frequency with and without bovine urine addition to pasture. Nitrous oxide fluxes were measured daily for 35 d. Soil O, temperature, and water content were continuously measured at multiple depths. Inorganic nitrogen, organic carbon, and soil pH were measured at 6-d intervals. Measurements of denitrification enzyme activity with and without acetylene inhibition were used to infer the NO/(NO + N) ratio. The NO/(NO + N) ratio was lower under high- compared with low-frequency irrigation, suggesting greater potential for NO reduction to N with more frequent irrigation. Although NO fluxes were increased by urine addition, they were not affected by irrigation frequency. Soil O decreased temporarily after urine deposition, but O dynamics did not explain NO dynamics. Relative soil gas diffusivity (/) was a better predictor of NO fluxes than O concentration. On a free-draining soil, increasing irrigation frequency while providing the same total water volume did not enhance NO emissions under ruminant urine patches in a grazed pasture. PMID:27380064

  18. Effects of long-term irrigation with treated wastewater on soil quality, soil-borne pathogens, and living organisms: case study of the vicinity of El Hajeb (Tunisia).

    Science.gov (United States)

    Hentati, Olfa; Chaker, Sana; Wali, Ahmed; Ayoub, Tarek; Ksibi, Mohamed

    2014-05-01

    Medium (i.e. 15 years) and long-term (i.e. 20 years) impact of irrigation using secondary-treated municipal wastewater (TWW) was assessed on two agricultural soil samples, denoted by E and G, respectively, in the vicinity of El Hajeb region (Southern Tunisia). Soil pH, electrical conductivity particle size grading, potential risk of salinity, water holding capacity and chemical composition, as well as organic matter content, pathogenic microorganisms and heavy metal concentrations in the TWW-irrigated (E and G) and rainwater-irrigated (T) soils at various depths, were monitored and compared during a 5-year experiment. Our study showed that bacterial abundance is higher in sandy-clayey soil, which has an enhanced ability to retain moisture and nutrients. The high level of bacterial flora in TWW-irrigated soils was significantly (p springtails, but they seem to be less sensitive to the living conditions in transects G and E than the earthworms. The avoidance response test of Eisenia andrei was statistically correlated with soil layers at the sampling sites. However, the avoidance response test of Folsomia candida was positively correlated with silt-clay content (+0.744*) and was negatively correlated with sand content (-0.744*). PMID:24362513

  19. Fungi colonizing the soil and roots of tomato (Lycopersicum esculentum Mill. plants treated with biological control agents

    Directory of Open Access Journals (Sweden)

    Bożena Cwalina-Ambroziak

    2012-12-01

    Full Text Available Tomato plants, cv. Rumba Ożarowska, grown in the greenhouse of the University of Warmia and Mazury, were protected in the form of alternate spraying (twice and watering (twice with 5% aqueous extracts of the following plant species: Aloe vulgaris Lam., Achillea millefolium L., Mentha piperita L., Polygonum aviculare L., Equisetum arvense L., Juglans regia L. and Urtica dioica L. Plants not treated with the extracts served as control. After fruit harvest, samples of roots and soil were collected. The roots were disinfected and next placed on PDA medium. Soil-colonizing fungi were cultured on Martin medium. Fungi were identified microscopically after incubation. Pathogenic fungal species, Colletotrichum coccodes, Fusarium equiseti, F. oxysporum and F. poae, accounted for over 60% of all isolates obtained from the roots of tomato plants. The soil fungal community was dominated by yeast-like fungi (75.4%, whereas pathogenic fungi were present in low numbers. The applied 5% aqueous plant extracts effectively reduced the abundance of fungi, including pathogenic species, colonizing tomato plants and soil. The extract from P. aviculare showed the highest efficacy, while the extract from J. regia was least effective. Fungi showing antagonistic activity against pathogens (Paecilomyces roseum and species of the genus Trichoderma were isolated in greatest abundance from the soil and the roots of tomato plants treated with A. millefolium, M. piperita and U. dioica extracts.

  20. Effect of land application of manure from enrofloxacin-treated chickens on ciprofloxacin resistance of Enterobacteriaceae in soil.

    Science.gov (United States)

    Pourcher, A-M; Jadas-Hécart, A; Cotinet, P; Dabert, P; Ziebal, C; Le Roux, S; Moraru, R; Heddadj, D; Kempf, I

    2014-06-01

    A field plot experiment was carried out to evaluate the impact of spreading chicken manure containing enrofloxacin (ENR) and its metabolite ciprofloxacin (CIP), on the levels of CIP-resistant Enterobacteriaceae in soil. The manures from chickens treated with ENR and from untreated control chickens were applied on six plots. Total and CIP-resistant Enterobacteriaceae were counted on Violet Red Bile Glucose medium containing 0 to 16mg L(-1) of CIP. A total of 145 isolates were genotyped by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The minimum inhibitory concentration (MIC) of CIP for the isolates of each ERIC-PCR profile was determined. The most frequently isolated Enterobacteriaceae included Escherichia coli, and to a lesser extent, Enterobacter and 5 other genera from environmental origin. The composition of the E. coli community differed between manure and manured soil suggesting that the E. coli genotypes determined by ERIC-PCR varied significantly in their ability to survive in soil. One of these genotypes, including both susceptible and resistant isolates, was detected up to 89 days after the manure was applied. Most of the E. coli isolated in soil amended with manure from treated chickens was resistant to CIP (with a MIC ranging between 2 and 32mg L(-1)). In contrast, despite the presence of ENR in soil at concentrations ranging from 13-518μg kg(-1), the environmental Enterobacteriaceae isolates had a CIP MIC≤0.064mg L(-1), except one isolate which had a MIC of 0.25mg L(-1), These results showed that spreading manure from ENR-treated chickens enabled CIP-resistant E. coli to persist for at least three months in the soil. However, neither the presence of fluoroquinolones, nor the persistence of CIP-resistant E. coli, increased the CIP-susceptibility of environmental Enterobacteriaceae.

  1. Effect of Studs on Reinforced Soil-cement Retaining Wall in High Stress Area%加栓钉对高应力区插筋SMW工法的影响研究

    Institute of Scientific and Technical Information of China (English)

    许俊红; 王媛; 李爱群

    2012-01-01

    针对传统高应力区插筋的SMW工法中型钢与水泥土的自然粘结较弱、不足以保证组合梁在大荷载时界面处有足够的共同作用的缺点,提出了在SMW工法型钢翼缘焊接栓钉的方法.并对型钢翼缘侧焊接栓钉的高应力区插筋的SMW工法进行了理论分析和ABAQUS有限元计算.通过理论分析,引入栓钉-水泥土-型钢组合结构概念,并建立了型钢-水泥土-栓钉三者相互作用的结构力学模型和抗弯承载力验算公式;数值计算结果则表明,焊接栓钉后,挡墙侧向位移、型钢位移、交界面的剪切力都比无栓钉情况有较好改善,最后计算并分析了不同栓钉特性对桩体位移、剪切力方面的影响.%Natural bond between steel and soil cement can not provide enough bonding strength to the interface of traditional reinforced soil-cement retaining wall in high stress area. For this weakness, a solution to this problem is given梬elding studs on steel flange. The theoretical analysis and ABAQUS finite element numerical computation are given to the reinforced soil-cement retaining wall in high stress area with welding studs on steel flange. Through theoretical analyzing, a studs-steel-cemented soil compound structure concept is introduced, and a mechanical model for interaction of these three elements is established, a checking formula in flexural bearing capacity of composite beam with studs is obtained; Numerical results show that the condition of lateral displacement of retaining wall and profile steel, and shear stress at interface is better than that of the wall without studs. Finally, the effects of lateral displacement of retaining wall and shear stress with different characteristics of studs are given.

  2. Gamma-ray-computed tomography to investigate compaction on sewage-sludge-treated soil

    Energy Technology Data Exchange (ETDEWEB)

    Pires, L.F. E-mail: lfpires@cena.usp.br; Macedo, J.R. de; Souza, M.D. de; Bacchi, O.O.S.; Reichardt, Klaus

    2003-07-01

    Soil compaction is one of the fundamental parameters to evaluate the environmental impact of agricultural machinery traffic on soils. Compaction causes modifications on soil physical properties such as changes in porosity and structure that are related to soil water movement and gas exchange The objective of this work was to evaluate soil surface sealing after sewage-sludge application, and the influence of agricultural machinery traffic, through computed tomography. A first generation tomograph was used having a {sup 137}Cs source and a 3 inx3 in NaI(Tl) scintillation crystal detector coupled to a photomultiplier tube. Image analysis and tomographic unit profiles could successfully be used for the detection of soil surface sealing and soil compaction due to machinery traffic associated to sewage-sludge application.

  3. Chemical speciation and bioavailability of cadmium in the temperate and semiarid soils treated with wheat residue.

    Science.gov (United States)

    Safari Sinegani, Ali Akbar; Jafari Monsef, Milad

    2016-05-01

    Heavy metal bioavailability depends on metal fractions in soil. The impacts of mild wheat residue (soils sampled from Hamadan and Lahijan, Iran with semiarid and temperate climates, respectively. Two factorial experiments were done in two soils polluted with 10 μg Cd g(-1) soil separately. Organic matter (0 and 5 % wheat straw) and soil incubation time (24 and 3600 h) were factors examined in three replicates. The transformation of Cd from KNO3 extractable form to less available fractions was higher in semiarid soils with lower clay and OM contents and higher pH and carbonate contents compared to temperate soils. In polluted semiarid soils after 24 h incubation, greater content of Cd was observed in residual (HNO3 extractable) (45 %), carbonates associated (EDTA extractable) (34 %), organic matter associated (NaOH extractable) (11 %), and KNO3 extractable (10 %) fractions, but in temperate soils, greater content of Cd was observed in KNO3 extractable (61 %), HNO3 extractable (14 %), EDTA extractable (13 %), and NaOH extractable (12 %) fractions. KNO3 extractable form of Cd was decreased, and NaOH extractable and HNO3 extractable forms of Cd were increased by addition of wheat residue to both soils. The initial decrease of added Cd from KNO3 extractable form to less mobile fractions in Hamadan soil was very interesting. But this change was not observed in Lahijan soil. Since contamination factor was significantly high in temperate soils compared to semiarid soils in all treatments, the risk of Cd environmental pollution in temperate region is considerably high.

  4. Community Structure of Ammonia-Oxidizing Archaea and Ammonia-Oxidizing Bacteria in Soil Treated with the Insecticide Imidacloprid

    Directory of Open Access Journals (Sweden)

    Mariusz Cycoń

    2015-01-01

    Full Text Available The purpose of this experiment was to assess the effect of imidacloprid on the community structure of ammonia-oxidizing archaea (AOA and ammonia-oxidizing bacteria (AOB in soil using the denaturing gradient gel electrophoresis (DGGE approach. Analysis showed that AOA and AOB community members were affected by the insecticide treatment. However, the calculation of the richness (S and the Shannon-Wiener index (H values for soil treated with the field rate (FR dosage of imidacloprid (1 mg/kg soil showed no changes in measured indices for the AOA and AOB community members. In turn, the 10*FR dosage of insecticide (10 mg/kg soil negatively affected the AOA community, which was confirmed by the decrease of the S and H values in comparison with the values obtained for the control soil. In the case of AOB community, an initial decline followed by the increase of the S and H values was obtained. Imidacloprid decreased the nitrification rate while the ammonification process was stimulated by the addition of imidacloprid. Changes in the community structure of AOA and AOB could be due to an increase in the concentration of N-NH4+, known as the most important factor which determines the contribution of these microorganisms to soil nitrification.

  5. Comparing the reinforcing effects of a resin modified glassionomer cement, Flowable compomer, and Flowable composite in the restoration of calcium hydroxide-treated immature roots in vitro

    Directory of Open Access Journals (Sweden)

    S Prathibha Rani

    2011-01-01

    Full Text Available One hundred and sixty human permanent central incisors were enlarged to a 120 file size after crown removal procedure to simulate immature teeth. The root canals were filled with calcium hydroxide and stored for 15 days (phase I, 30 days (phase II, 90 days (phase III, and 180 days (Phase IV. At the end of these selected time periods, calcium hydroxide was cleaned off the root canals of forty teeth that were randomly selected and obturated with gutta-percha points in the apical 2 mm of the root canals with a sealer. The specimens were further equally divided into four groups. Unrestored Group I served as control and the root canals of teeth in the other three group specimens were reinforced with resin modified glassionomer cement (RMGIC (Group II, Flowable Compomer (Group III, and Flowable Composite (Group IV, respectively, using a translucent curing post. All specimens were subjected to compressive force using an Instron Testing machine, until fracture occurred. All the materials evaluated substantially reinforced the root specimens compared to the control. At the end of 180 days, Flowable composites showed maximum reinforcement compared to the other groups; however, no significant differences were found between the reinforcement capabilities of Flowable Compomer and RMGIC.

  6. An example of treated waste water use for soil irrigation in the SAFIR project.

    OpenAIRE

    Cary, Lise; Jovanovic, Z; Stikic, R.; Blagojevic, S.; Kloppmann, Wolfram

    2009-01-01

    via contact with irrigation water, soil, crops and food, consumers, exposed via ingestion of fresh and processed food), for animals (via ingestion of crops on soil), for the crops and agricultural productivity (via salinity and trace element uptake), for soil (via accumulation or release of pollutants) as well as for surface, groundwaters and the associated ecosystems (via runoff and infiltration, Kass et al., 2005, Bouwer, 2000). In this context, the European FP6 SAFIR project (Safe and High...

  7. Examination of zinc adsorption capacity of soils treated with different pyrolysis products

    OpenAIRE

    Rétháti Gabriella; Vejzer Adrienn; Simon Barbara; Benjared Ramadan; Füleky György

    2014-01-01

    Organic matter input into soils is essential regarding agricultural, environmental and soil science aspects as well. However, the application of the pyrolysed forms of biochars and materials with different organic matter content gained more attention in order to decrease the emission of the green house gases (CO2, N2O) from the soil. During pyrolysis, the materials containing high organic matter (biomass-originated organic matter) are heated in oxygen-free (or limited amount of oxygen) enviro...

  8. Dynamic Characteristics of Saturated Silty Soil Ground Treated by Stone Column Composite Foundation

    OpenAIRE

    Yongxiang Zhan; Guanlu Jiang; Hailin Yao

    2014-01-01

    A shaking table model test was carried out to develop an understanding of the performance improvement of saturated silty soil ground using stone column composite foundation as reinforcement. It is found that at less than 0.161 g loading acceleration, soil between piles has not yet been liquefied, the response acceleration scarcely enlarges, and the shear displacement almost does not appear in silty soil. At 0.252 g loading acceleration, as a result of liquefaction of soil between piles, the r...

  9. Simulation of cement-improved clay structures with a bonded elasto-plastic model: A practical approach

    OpenAIRE

    Arroyo Alvarez de Toledo, Marcos; Ciantia, M.; Castellanza, Riccardo; Gens Solé, Antonio; NOVA, ROBERTO

    2012-01-01

    Engineering practice has usually dealt with the treated soil bodies using simplistic constitutive models (e.g. elastic perfectly-plastic Mohr–Coulomb). In this paper, a more refined bonded elasto-plastic model is here applied, with emphasis on the ease of calibration. Empirical studies have identified the ratio of cement content to the cured mixture void ratio as a controlling variable for mechanical response. This observation is elaborated upon to show that measuring porosity and unconfined ...

  10. Experimental Study of the Ground Penetrating Radar Monitoring on the Integrity of Tamping Soil Cement Pile%夯实水泥土桩桩身完整性探地雷达检测技术试验研究

    Institute of Scientific and Technical Information of China (English)

    王海东; 张梦; 邓继平; 罗杰; 杨献章; 廖春芳

    2012-01-01

    针对复合地基柔性桩基桩身完整性难以检测的实际工程问题,提出了组合天线阵方式的探地雷达检测技术.通过对6根夯实水泥土桩桩长和桩身缺陷检测试验研究发现,桩长检测的最大平均相对误差为5.10%,桩身缺陷位置检测相对误差为5.45%,表明采用此技术对复合地基柔性桩基桩身完整性进行测定具有足够的可靠性,满足工程需要.通过对龄期、配合比、含水率和天线选择等影响因素的分析,得到了这些参数对检测质量的影响规律,并据此为工程应用提出了相应合理建议.%The combination of antenna array detection method of ground penetrating radar was put forward to solve the actual engineering problem that is difficult to monitor the integrity of the flexural pile composite foundation. The experiments of the lengths and defects of six tamping soil cement piles have shown that the maximum average relative error of pile lengths is 5. 10% and the relative error of the pile position of defects is 5. 45%. The results have indicated that there is enough reliability to determine the pile integrity by using the GPR method, which can meet the engineering needs. Furthermore, the age of cement, the ratio between soil and cement, moisture content were studied, and corresponding proposals for actual projects were presented.

  11. Effect of irrigation with industrial treated wastewater on variation trend of some heavy metals in soil and radish (Raphanus Sativus plant

    Directory of Open Access Journals (Sweden)

    Gh. Rahimi

    2016-02-01

    Full Text Available Limited water resources in arid and semi-arid regions are one of the major limiting factors in agricultural production. Thus, unconventional water resources, such as urban and industrial treated wastewater, may be used for irrigation. Application of wastewater to soil may cause accumulation of heavy metals (HMs. Soil pollution causes uptake of these metals by plants and their entrance to food chain. In the present greenhouse research, concentration variations of HMs (zinc, copper, cadmium, nickel, iron and manganese in soil and radish plant were investigated. The experiment was conducted as a completely randomized design with three replications and irrigation with different percentages of treated wastewater (0, 25, 50, 75 and 100%. Results of soil chemical analysis showed that irrigation with treated wastewater significantly increased sodium adsorption ratio, salinity level and chloride content of soil. While, using different percentages of treated wastewater decreased significantly (P≤0.01 soil pH. Results revealed that total and available concentrations of HMs in soil irrigated with wastewater were higher than the those in soil irrigated with tap water. However, metal concentrations were much lower than the critical limits in soil. Therefore, had no adverse effects on soil quality. The results also showed that HM concentration in roots and aerial parts of radish plant was not increased significantly as a result of wastwater irrigation.

  12. Chemical pools of Cd in sludge-treated soils and their contribution of Rajmash (Phaseolus vulgaris L)

    International Nuclear Information System (INIS)

    To study the influence of application of organically complexed Cd on Rajmash (Phaseo/us vu/garis L,), a pot experiment was conducted on ten sewage sludge-treated old), alluvium, non-calcareoUS, and non-saline soils of Patna wherein a rajmash crop was grown after treatment with O and 5 mg kg-l isotopicaIly tagged and organically-complexed Cd. The results indicated that the application of Cd through cadmium-fulvic acid complex in soils did not influence the dry matter yield of the crop, though it significantly increased the concentration of Cd in the plants and its uptake by the crop, The soil organic carbon content, cation exchange, capacity, clay content and pH of the soils were found to be the dominant determinants of Cd in plants and its uptake by the crop. The path analysis and stepwise regression analysis indicated that the water soluble + exchangeable Cd and organically complexed Cd were the two major chemical pools of Cd in soils responsible for supply of Cd 10 the plants

  13. Heavy metals in a degraded soil treated with sludge from water treatment plant

    Directory of Open Access Journals (Sweden)

    Teixeira Sandra Tereza

    2005-01-01

    Full Text Available The application of water treatment sludge (WTS to degraded soil is an alternative for both residue disposal and degraded soil reclaim. This study evaluated effects of the application of water treatment sludge to a Typic Hapludox soil degraded by tin mining in the National Forest of Jamari, State of Rondonia, Brazil, on the content of heavy metals. A completely randomized experimental design with five treatments was used: control (n = 4; chemical control, which received only liming (n = 4; and rates D100, D150 and D200, which corresponded to 100, 150 and 200 mg of N-sludge kg-1 soil (n = 20, respectively. Thirty days after liming, period in which soil moisture was kept at 70% of the retention capacity, soil samples were taken and analyzed for total and extractable Fe, Cu, Mn, Zn, Cd, Pb, Ni, and Cr. The application of WTS increased heavy-metal contents in the degraded soil. Although heavy metals were below their respective critical limits, sludge application onto degraded areas may cause hazardous environmental impact and thus must be monitored.

  14. Phosphorus availability in oxidic soils treated with lime and silicate applications

    Directory of Open Access Journals (Sweden)

    Aline da Silva Sandim

    2014-08-01

    Full Text Available Based on the assumption that silicate application can raise soil P availability for crops, the aim of this research was to compare the effect of silicate application on soil P desorption with that of liming, in evaluations based on two extractors and plant growth. The experiment was carried out in randomized blocks with four replications, in a 3 × 3 × 5 factorial design, in which three soil types, three P rates, and four soil acidity correctives were evaluated in 180 experimental plots. Trials were performed in a greenhouse using corn plants in 20-dm³ pots. Three P rates (0, 50 and 150 mg dm-3 were applied in the form of powder triple superphosphate and the soil was incubated for 90 days. After this period, soil samples were collected for routine chemical analysis and P content determination by the extraction methods resin, Mehlich-1 and remaining P. Based on the results, acidity correctives were applied at rates calculated for base saturation increased to 70 %, with subsequent incubation for 60 more days, when P content was determined again. The acidity correctives consisted of: dolomitic lime, steelmaking slag, ladle furnace slag, and wollastonite. Therefore, our results showed that slags raised the soil P content more than lime, suggesting a positive correlation between P and Si in soil. Silicon did not affect the extractor choice since both Mehlich-1 and resin had the same behavior regarding extracted P when silicon was applied to the soil. For all evaluated plant parameters, there was significant interaction between P rates and correctives; highest values were obtained with silicate.

  15. Potential use of soil-born fungi isolated from treated soil in Indonesia to degrade glyphosate herbicide

    Directory of Open Access Journals (Sweden)

    N. Arfarita

    2014-01-01

    Full Text Available The glyphosate herbicide is the most common herbicides used in palm-oil plantations and other agricultural in Indonesial. In 2020, Indonesian government to plan the development of oil palm plantations has reached 20 million hectares of which now have reached 6 million hectares. It means that a huge chemicals particularly glyphosate has been poured into the ground and continues to pollute the soil. However, there is no report regarding biodegradation of glyphosate-contaminated soils using fungal strain especially in Indonesia. This study was to observe the usage of Round Up as selection agent for isolation of soil-born fungi capable to grow on glyphosate as a sole source of phosphorus. Five fungal strains were able to grow consistently in the presence of glyphosate as the sole phosphorus source and identified as Aspergillus sp. strain KRP1, Fusarium sp. strain KRP2, Verticillium sp. strain KRP3, Acremoniumsp. strain GRP1 and Scopulariopsis sp. strain GRP2. This indicates as their capability to utilize and degrade this herbicide. We also used standard medium as control and get seventeen fungal strains. The seventeen fungal strains were identified as species of Botrytis, Fusarium, Aspergillus, Penicillium, Verticillium, Trichoderma and Paecilomyces. These results show the reduction in the number of fungal strains on solid medium containing glyphosate. Of the five isolated fungal species, Verticillium sp. strain KRP3 and Scopulariopsis sp. strain GRP2 were selected for further study based on their highest ratio of growth diameter. This study indicates that treatment of soil with glyphosate degrading fungus would be useful in some areas where this herbicide is extensively used

  16. Potential use of soil-born fungi isolated from treated soil in Indonesia to degrade glyphosate herbicide

    Directory of Open Access Journals (Sweden)

    N. Arfarita

    2014-01-01

    Full Text Available The glyphosate herbicide is the most common herbicides used in palm-oil plantations and other agricultural in Indonesial. In 2020, Indonesian government to plan the development of oil palm plantations has reached 20 million hectares of which now have reached 6 million hectares. It means that a huge chemicals particularly glyphosate has been poured into the ground and continues to pollute the soil. However, there is no report regarding biodegradation of glyphosate-contaminated soils using fungal strain especially in Indonesia. This study was to observe the usage of Round Up as selection agent for isolation of soil-born fungi capable to grow on glyphosate as a sole source of phosphorus. Five fungal strains were able to grow consistently in the presence of glyphosate as the sole phosphorus source and identified as Aspergillus sp. strain KRP1, Fusarium sp. strain KRP2, Verticillium sp. strain KRP3, Acremoniumsp. strain GRP1 and Scopulariopsis sp. strain GRP2. This indicates as their capability to utilize and degrade this herbicide. We also used standard medium as control and get seventeen fungal strains. The seventeen fungal strains were identified as species of Botrytis, Fusarium, Aspergillus, Penicillium, Verticillium, Trichoderma and Paecilomyces. These results show the reduction in the number of fungal strains on solid medium containing glyphosate. Of the five isolated fungal species, Verticillium sp. strain KRP3 and Scopulariopsis sp. strain GRP2 were selected for further study based on their highest ratio of growth diameter. This study indicates that treatment of soil with glyphosate degrading fungus would be useful in some areas where this herbicide is extensively used.

  17. CCA transport in soil from treated-timber posts: pattern dynamics from the local to regional scale

    Directory of Open Access Journals (Sweden)

    B. E. Clothier

    2006-08-01

    Full Text Available Winegrape growing in many parts of the world, including Marlborough, New Zealand, uses treated-timber posts to act as supports for the grapevine's canopy. At a density of 580 posts per hectare, the H4-process treated supports result in an areal loading of CCA of: Copper (12 kg-Cu ha−1, Chromium (21 kg-Cr ha−1 and Arsenic (17 kg-As ha−1. Arsenic is the most mobile and toxic of the CCA-treatment cocktail. We describe experiments which indicate that about 4–6 mg-As month−1 post−1 is released from the subterranean part of the post. We have used SPASMO (Soil Plant Atmosphere System Model to predict post-to-soil leakage, as well as the pattern dynamics of leaching and exchange around the post. Locally the pattern dynamics of transport and fate are controlled by the soil's chemical characteristics and the prevailing weather. Over its 20-year lifetime, the concentration of arsenic, both that adsorbed on the soil and in the soil solution, exceeds guideline values for soils (100 mg-As kg−1 and drinking water (10 μg-As L−1. Under a regime of 5% annual replacement of posts, the spatially averaged concentration of arsenic leaching through the soil is predicted to rise to 1.25 to 1.7 times the drinking water standard, depending only slightly on the soil type. The steady value is primarily controlled by the arsenic-release rate from the post. These steady values were used in a simple hydrogeological model of the major Marlborough aquifer systems to determine whether the subterranean flow of water could dilute the descending plumes of arsenic coming from above. Except for the sluggish aquifers of the southern valleys in Marlborough, most of the aquifer systems seem capable of diluting the leachate to between one tenth and one twentieth of the drinking water standard. The upscaling of our modelling of the local pattern dynamics spanned six orders of spatial

  18. CCA transport in soil from treated-timber posts: pattern dynamics from the local to regional scale

    Science.gov (United States)

    Clothier, B. E.; Green, S. R.; Vogeler, I.; Greven, M. M.; Agnew, R.; van den Dijssel, C. W.; Neal, S.; Robinson, B. H.; Davidson, P.

    2006-08-01

    Winegrape growing in many parts of the world, including Marlborough, New Zealand, uses treated-timber posts to act as supports for the grapevine's canopy. At a density of 580 posts per hectare, the H4-process treated supports result in an areal loading of CCA of: Copper (12 kg-Cu ha-1), Chromium (21 kg-Cr ha-1) and Arsenic (17 kg-As ha-1). Arsenic is the most mobile and toxic of the CCA-treatment cocktail. We describe experiments which indicate that about 4-6 mg-As month-1 post-1 is released from the subterranean part of the post. We have used SPASMO (Soil Plant Atmosphere System Model) to predict post-to-soil leakage, as well as the pattern dynamics of leaching and exchange around the post. Locally the pattern dynamics of transport and fate are controlled by the soil's chemical characteristics and the prevailing weather. Over its 20-year lifetime, the concentration of arsenic, both that adsorbed on the soil and in the soil solution, exceeds guideline values for soils (100 mg-As kg-1) and drinking water (10 μg-As L-1). Under a regime of 5% annual replacement of posts, the spatially averaged concentration of arsenic leaching through the soil is predicted to rise to 1.25 to 1.7 times the drinking water standard, depending only slightly on the soil type. The steady value is primarily controlled by the arsenic-release rate from the post. These steady values were used in a simple hydrogeological model of the major Marlborough aquifer systems to determine whether the subterranean flow of water could dilute the descending plumes of arsenic coming from above. Except for the sluggish aquifers of the southern valleys in Marlborough, most of the aquifer systems seem capable of diluting the leachate to between one tenth and one twentieth of the drinking water standard. The upscaling of our modelling of the local pattern dynamics spanned six orders of spatial magnitude, and four orders of time dimension.

  19. TRACE ELEMENT CHEMISTRY IN RESIDUAL-TREATED SOIL: KEY CONCEPTS AND METAL BIOAVAILABILITY

    Science.gov (United States)

    Trace element solubility and availability in land-applied residuals is governed by fundamental chemical reactions between metal constituents, soil, and residual components. Iron, aluminum, and manganese oxides; organic matter; and phosphates, carbonates, and sulfides are importan...

  20. Características físicas e mecânicas de misturas de solo, cimento e casca de arroz Physical and mechanical characteristics of soil-cement and rice husk mixtures

    Directory of Open Access Journals (Sweden)

    Ana P. S. Milani

    2006-04-01

    Full Text Available Na presente pesquisa, estudaram-se os efeitos da adição da casca de arroz nas propriedades físico-mecânicas da mistura de solo-cimento, visando a obter composições de solo-cimento-casca de arroz com potencialidade para fabricação de materiais alternativos de construção. Foram realizados o fracionamento, o peneiramento e o pré-tratamento em solução de cal da casca de arroz. Foram determinadas as características físicas do solo e da casca de arroz, sendo executados ensaios de dosagem das misturas de solo-cimento-casca de arroz, aplicando-se às mesmas os ensaios de compactação normal de Proctor e o de compressão simples. Posteriormente, as composições de solo-cimento-casca de arroz foram submetidas aos ensaios de compressão simples e de tração na compressão diametral, aos 7 e aos 28 dias de idade, e de absorção d'água. Depois de determinadas as principais características físicas e mecânicas, pôde-se concluir que as misturas de solo + teor de 12% de combinações de cimento e casca de arroz se apresentaram como materiais promissores para a fabricação de elementos construtivos, a serem utilizados em construções e instalações rurais.The main objective of this work is the study of the effect of rice husk addition on the physical and mechanical properties of soil-cement, in order to obtain an alternative construction material. The rice husk preparation consisted of grinding, sieving, and the pre-treatment with lime solution. The physical characteristics of the soil and of the rice husk were determined. Different amounts of soil, cement and rice husk were tested by compaction and unconfined compression. The specimens molded according to the treatments applied to the mixtures were subsequently submitted to compression testing and to tensile splitting cylinder testing at 7 and 28 days of age and to water absorption testing. After determining its physical and mechanical characteristics, the best results were obtained

  1. Misturas de um solo laterítico com cimento e bentonita para uso em cortinas verticais Mixtures of a lateritic soil with cement and bentonite for slurry wall purposes

    Directory of Open Access Journals (Sweden)

    Priscila Batista

    2010-06-01

    Full Text Available É crescente mundo afora o uso de cortinas verticais para contenção da contaminação em água subterrânea. Os solos lateríticos, pela sua ampla distribuição no Brasil, possuem grande potencial de aplicação nessas obras. Entretanto algumas questões ainda carecem de maior investigação, como a interação e compatibilidade desses solos com a bentonita e o cimento, principais aditivos usados para melhorar as propriedades das cortinas. O presente artigo avalia propriedades de um solo laterítico e suas misturas com bentonita e cimento, incluindo a investigação de parâmetros geotécnicos mecânicos e hidráulicos. A campanha laboratorial consistiu de ensaios de caracterização física, físico-química e mineralógica, de condutividade hidráulica, de compressão simples e de cisalhamento direto. Os resultados demonstram que a adição de 3% de bentonita em amostras compactadas não trouxe a diminuição esperada da condutividade hidráulica do solo laterítico, ainda que tenha proporcionado um considerável incremento na resistência ao cisalhamento da mistura.There is an increasing worldwide demand for slurry walls to contain contaminated groundwater. Lateritic soils, due to their wide distribution in the Brazilian territory, have great potential to be used in these cases. However, some issues remain uncertain and need investigation, including the interaction and compatibility of these soils with bentonite or cement, the most used additives to improve their geotechnical properties. This work evaluates some mechanical and hydraulic properties of a lateritic soil sample and its mixtures with bentonite and cement. The laboratorial procedures consisted of physical, physico-chemical and mineralogical characterization, hydraulic conductivity, uniaxial compression and direct shearing testing. The results demonstrate that the addition of 3% of bentonite in compacted samples did not decrease the hydraulic conductivity of the lateric soil as

  2. Organic phosphorus in solutions and leachates from soils treated with animal slurries

    OpenAIRE

    Chardon, W.J.; Oenema, O.; del Castilho, P; Vriesema, R.; Japenga, J.; Blaauw, D.

    1997-01-01

    A substantial part of the total phosphorus (P) in soil solution and leachates can be present as dissolved organic phosphorus (DOP). The DOP may be more mobile than inorganic orthophosphate and thus it can be an important P source for surface water eutrophication. This paper describes a series of four experiments that investigated the effects of animal waste application to sandy soil on DOP leaching. The first experiment examined the effect of storing pig slurry on DOP fractionation, using gel...

  3. Dynamic Characteristics of Saturated Silty Soil Ground Treated by Stone Column Composite Foundation

    Directory of Open Access Journals (Sweden)

    Yongxiang Zhan

    2014-01-01

    Full Text Available A shaking table model test was carried out to develop an understanding of the performance improvement of saturated silty soil ground using stone column composite foundation as reinforcement. It is found that at less than 0.161 g loading acceleration, soil between piles has not yet been liquefied, the response acceleration scarcely enlarges, and the shear displacement almost does not appear in silty soil. At 0.252 g loading acceleration, as a result of liquefaction of soil between piles, the response acceleration increases rapidly and reaches its peak, and the shear displacement of silty soil increases significantly. At 0.325 g loading acceleration, the integral rigidity of foundation decreases greatly, which reduces its capability of vibration transmission and result in the response acceleration amplification coefficient is less than that at the former loading acceleration, but the shear displacement of silty soil further increases. The stone column composite foundation can greatly reduce both the shear displacement and the settlement of ground compared with untreated foundation. Under the condition of 7-degree seismic fortification, the design meets seismic resistance requirements.

  4. Asphalt cement poisoning

    Science.gov (United States)

    ... petroleum material that hardens when it cools. Asphalt cement poisoning occurs when someone swallows asphalt. If hot ... found in: Road paving materials Roofing materials Tile cements Asphalt may also be used for other purposes.

  5. The survival of Escherichia coli, faecal coliforms and enterobacteriaceae in general in soil treated with sludge from wastewater treatment plants.

    Science.gov (United States)

    Estrada, I B; Aller, A; Aller, F; Gómez, X; Morán, A

    2004-06-01

    We monitored the effect of the application of treated sludge on the behaviour of enterobacteriaceae (mainly faecal coliforms and especially Escherichia coli) in the soil, and studied their evolution over time after application. Three different sludges were used: two from a municipal sewage plant, one of them had been subjected to anaerobic digestion and heat drying, and the other to anaerobic digestion and mechanical dehydration, and one from a dairy waste treatment to aerobic digestion and gravity thickening. Two types of tests were carried out: type O, in the open air, with no possibility of controlling humidity or temperature; and type L, under laboratory conditions, with controlled temperature and humidity. Sludge tests were also run on unscreened soil previously treated with chemical fertilizer. After 80 days of experimentation the populations of faecal coliforms and E. coli had decreased considerably or were undetectable in assays carried out on the soil/sludge mixtures, under both open-air and laboratory conditions, but that, over the same period, in the mixtures containing chemical fertilizer (calcium ammonium nitrate) there had been a considerable increase in the micro-organism populations studied. PMID:15051081

  6. Changes in the chemical composition of an acidic soil treated with marble quarry and marble cutting wastes.

    Science.gov (United States)

    Tozsin, Gulsen; Oztas, Taskin; Arol, Ali Ihsan; Kalkan, Ekrem

    2015-11-01

    Soil acidity greatly affects the availability of plant nutrients. The level of soil acidity can be adjusted by treating the soil with certain additives. The objective of this study was to determine the effect of marble quarry waste (MQW) and marble cutting waste (MCW) on the chemical composition and the acidity of a soil. Marble wastes at different rates were applied to an acid soil. Their effectiveness in neutralizing the soil pH was compared with that of agricultural lime. The changes in the chemical composition of the soil were also evaluated with column test at the end of a 75-day incubation period. The results indicated that the MQW and MCW applications significantly increased the soil pH (from 4.71 up to 6.54), the CaCO3 content (from 0.33% up to 0.75%), and the exchangeable Ca (from 14.79 cmol kg(-1) up to 21.18 cmol kg(-1)) and Na (from 0.57 cmol kg(-1) up to 1.07 cmol kg(-1)) contents, but decreased the exchangeable K (from 0.46 cmol kg(-1) down to 0.28 cmol kg(-1)), the plant-available P (from 25.56 mg L(-1) down to 16.62 mg L(-1)), and the extractable Fe (from 259.43 mg L(-1) down to 55.4 mg L(-1)), Cu (from 1.97 mg L(-1) down to 1.42 mg L(-1)), Mn (from 17.89 mg L(-1) down to 4.61 mg L(-1)) and Zn (from 7.88 mg L(-1) down to 1.56 mg L(-1)) contents. In addition, the Cd (from 0.060 mg L(-1) down to 0.046 mg L(-1)), Ni (from 0.337 mg L(-1) down to 0.092 mg L(-1)) and Pb (from 28.00 mg L(-1) down to 20.08 mg L(-1)) concentrations decreased upon the treatment of the soil with marble wastes.

  7. Effect of Interactions on the Nutrient Status of a Tropical Soil Treated with Green Manures and Inorganic Phosphate Fertilizers

    Directory of Open Access Journals (Sweden)

    Abdul R. Bah

    2004-01-01

    Full Text Available Integrated nutrient management systems using plant residues and inorganic P fertilizers have high potential for increasing crop production and ensuring sustainability in the tropics, but their adoption requires in-depth understanding of nutrient dynamics in such systems. This was examined in a highly weathered tropical soil treated with green manures (GMs and P fertilizers in two experiments conducted in the laboratory and glasshouse. The treatments were factorial combinations of the GMs (Calopogonium caeruleum, Gliricidia sepium, and Imperata cylindrica and P fertilizers (phosphate rocks [PRs] from North Carolina, China, and Algeria, and triple superphosphate replicated thrice. Olsen P, mineral N, pH, and exchangeable K, Ca, and Mg were monitored in a laboratory incubation study for 16 months. The change in soil P fractions and available P was also determined at the end of the study. Phosphorus available from the amendments was quantified at monthly intervals for 5 months by 33P-32P double isotopic labeling in the glasshouse using Setaria sphacelata as test crop. The GMs were labeled with 33P to determine their contribution to P taken up by Setaria, while that from the P fertilizers was indirectly measured by labeling the soil with 32P. The P fertilizers hardly changed Olsen P and exchangeable cations during 16 months of incubation. The legume GMs and legume GM+P did not change Olsen P, lowered exchangeable Ca, and increased exchangeable K about threefold (4.5 cmol[+]kg−1 soil in the first 4 months, even as large amounts of NH4-N accumulated (~1000 mg kg soil−1 and soil pH increased to more than 6.5. Afterwards, Olsen P and exchangeable Ca and Mg increased (threefold as NH4+-N and soil pH declined. The legume GMs also augmented reversibly sorbed P in Al-P and Fe-P fractions resulting in high residual effect in the soil, while fertilizer-P was irreversibly retained. The GMs increased PR-P utilization by 40 to over 80%, mobilized soil P, and

  8. Speciation and phytoavailability of cadmium in soil treated with cadmium-contaminated rice straw.

    Science.gov (United States)

    Wang, Shuai; Huang, Dao-You; Zhu, Qi-Hong; Zhu, Han-Hua; Liu, Shou-Long; Luo, Zun-Chang; Cao, Xiao-Ling; Wang, Ji-Yu; Rao, Zhong-Xiu; Shen, Xin

    2015-02-01

    When grown on Cd-contaminated soil, rice typically accumulates considerable Cd in straw, and which may return to the soil after harvest. This work was undertaken to assess the pollution risk of Cd associated to the Cd-contaminated rice straw after incorporating into an uncontaminated soil. With the Cd-contaminated rice straw added at 0, 1, 2, 3, 4 and 5 % (w/w), an incubation experiment (28 days) with non-planting and a followed pot experiment sequent with two planting (rice and Chinese cabbage, transplanted after 28-day incubation) were carried out to investigate the changes of soil Cd speciation and phytoavailability. The results indicated that the Cd-contaminated rice straw addition significantly increased soil pH and dissolved organic carbon during the 28-day incubation. For the high availability of Cd in contaminated rice straw, diethylenetriaminepentaacetic acid (DTPA) extractable Cd significantly increased, and the percentages of acetic acid extractable and reducible Cd in soil significantly enhanced after the addition of Cd-contaminated rice straw. However, the Cd-contaminated rice straw addition inhibited the rice growth and induced the decrease of Cd in rice grain and straw by 12.8 to 70.2 % and 39.3 to 57.3 %, respectively, whereas the Cd contents increased by 13.9 to 84.1 % in Chinese cabbage that planted after rice harvest. In conclusion, Cd associated with Cd-contaminated rice straw was highly available after incorporating into the soil, and thus the Cd pollution risk via the Cd-contaminated rice straw incorporation should be evaluated in the Cd-contaminated paddy region.

  9. Experimental, numerical and sensitive analysis of nitrogen dynamics in soils irrigated with treated sewage

    Institute of Scientific and Technical Information of China (English)

    ZHU Yan; YANG dinZhong; WANG LiYing

    2009-01-01

    An ammonia volatilization submodel and a crop-growth submodel have been set up and Incorporated to the 2D nitrogen transport and transformation simulation model Nitrogen-2D.The coupled model Ni-trogen-2D considers all the important nitrogen transformation processes such as mineralization, im-mobilization, denitrification, nitrification, volatilization, root uptake and soil adsorption in the soil.The model was used to simulate the nitrogen dynamics for the experiment in four lysimeters under sewage irrigation.Simulation results show that the model can describe the water content and ammonium ni-trogen content distribution well but simulate the change of the nitrate nitrogen poorly.Sensitivity analysis shows that the simulation results are influenced by the soil water characteristic parameters severely, especially by the parameter of n.The model is much less sensitive to N dynamic parameters.

  10. Experimental,numerical and sensitive analysis of nitrogen dynamics in soils irrigated with treated sewage

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    An ammonia volatilization submodel and a crop-growth submodel have been set up and incorporated to the 2D nitrogen transport and transformation simulation model Nitrogen-2D. The coupled model Nitrogen-2D considers all the important nitrogen transformation processes such as mineralization, immobilization, denitrification, nitrification, volatilization, root uptake and soil adsorption in the soil. The model was used to simulate the nitrogen dynamics for the experiment in four lysimeters under sewage irrigation. Simulation results show that the model can describe the water content and ammonium nitrogen content distribution well but simulate the change of the nitrate nitrogen poorly. Sensitivity analysis shows that the simulation results are influenced by the soil water characteristic parameters severely, especially by the parameter of n. The model is much less sensitive to N dynamic parameters.

  11. Assessment of several extractants for determination of copper bioavailability to wheat (Triticum aestivum L.) in sewage sludge-treated calcareous soils

    OpenAIRE

    H.R. Motaghian; A. R. Hosseinpour; F. Raeisi; J.Mohammadi

    2013-01-01

    Copper (Cu) is an essential micronutrient for plants. However, determination of a suitable extractant of Cu in sewage sludge-amended calcareous soils has seldom been attended. The aim of this research was evaluating several extractants to predict available Cu in 10 untreated and sewage sludge-treated calcareous soils in greenhouse under wheat cultivation. After 1 month incubation, available Cu of soils was determined using 7 chemical procedures (DTPA-TEA, AB-DTPA, Mehlich 1, Mehlich 2, Mehlic...

  12. Plant uptake of selenium, arsenic and molybdenum from soil treated with coal combustion byproducts

    Energy Technology Data Exchange (ETDEWEB)

    Codling, E.E.; Wright, R.J. [US Department of Agriculture, Beltsville, MD (United States). Agricultural Research Service, Environmental Chemistry Dept.

    1998-01-01

    Three coal combustion byproducts, flyash (FA), scrubber sludge (SS) and gypsum (G), added to soil at rates of 0, 20, 40 and 80 g/kg only limited annual ryegrass (Lolium multiflorum) growth at the 80 g/kg rate. FA and SS increased selenium (Se), arsenic (As) and molybdenum (Mo) concentrations in ryegrass but only Se from FA would present a potential food chain risk. G did not significantly increase ryegrass concentrations of Se, As and Mo and should not produce elevated trace element levels in plant material or the environment when added to soil at high rates.

  13. Resin cementation of zirconia ceramics with different bonding agents

    OpenAIRE

    Tanış, Merve Çakırbay; Akay, Canan; Karakış, Duygu

    2015-01-01

    The aim of this study was to evaluate the effects of sandblasting and different chemical bonding agents on shear bond strength of zirconia and conventional resin cement. In this study, 35 zirconia specimens were treated as follows: Group I: control; Group II: sandblasting; Group III: sandblasting + Monobond S; Group IV: sandblasting + Monobond Plus; Group V: sandblasting + Z-Prime Plus. The specimens in each group were bonded with conventional composite resin cement Variolink II. After cement...

  14. 盐水环境下水泥土桩劣化效应及其对道路复合地基沉降的影响%Deterioration Effect of Soil-cement Pile Under Saltwater Environment and Its Influence on Composite Foundation Settlement of Road

    Institute of Scientific and Technical Information of China (English)

    崔新壮; 龚晓南; 李术才; 汤潍泽; 张炯

    2015-01-01

    In order to reveal deterioration effect of soil-cement pile in saltwater environment and its influence on road composite foundation settlement,the deterioration effect of soil-cement in Yellow River Delta in saltwater environment was investigated by model test.The deterioration depth of soil-cement and evolution laws of compressive strength in non-deteriorated regions were analyzed.Based on the conclusion of previous researches on soil-cement deterioration,a practical prediction method for entire life-cycle bearing capacity of soil-cement piles in saltwater environment was proposed based on soil-cement early strength test.At the same time,influence of deterioration of soil-cement pile on composite foundation settlement was investigated by model test and numerical simulation.The results show that during reinforcing the soft subsoil with high salinity groundwater,soil-cement piles are deteriorated from outside to inside.Deterioration of soil-cement has a great influence on bearing capacity of mixed pile,which increases settlement of composite foundation.Furthermore,the pile defects will aggravate deterioration effect of soilcement pile.In order to ensure sustainable stability of subgrade and control its long-term settlement,deterioration of soil-cement should be considered during the design of composite foundation in saltwater region.%为了揭示盐水环境下水泥土桩的劣化效应及其对道路复合地基沉降的影响,通过室内模型试验研究了黄河三角洲盐水环境下水泥土的劣化效应,分析了水泥土劣化深度和未劣化部分抗压强度的演化规律.通过对已有水泥土劣化研究成果进行总结分析,提出了基于水泥土早期强度试验的盐水环境下水泥土桩全寿命周期承载力实用预测方法;同时,通过模型试验和数值模拟研究了水泥土桩劣化对复合地基沉降的影响.研究结果表明:在加固地下水矿化度高的软弱地基时,水泥土桩会从外向内逐渐劣化;

  15. The use of treated wastewater for chemlali olive tree irrigation: effects on soil properties, growth and oil quality

    International Nuclear Information System (INIS)

    Olive tree (Olea european L.) cultivation, the major tree crops in Mediterranean countries is being extended to irrigated lands. However, the limited water availability, the severe climatic conditions and the increased need for good water quality for urban and industrial sector uses are leading to the urgent use of less water qualities (brackish water and recycled wastewater) for olive tree irrigation. The aim of this work was to asses the effects of long term irrigation with treated waste water (TWW) on the soil chemical properties, on olive tree growth and on oil quality characteristics. (Author)

  16. The use of treated wastewater for chemlali olive tree irrigation: effects on soil properties, growth and oil quality

    Energy Technology Data Exchange (ETDEWEB)

    Ben Rouina, B.; Bedbabis, S.; Ben Ahmed, C.; Boukhris, M.

    2009-07-01

    Olive tree (Olea european L.) cultivation, the major tree crops in Mediterranean countries is being extended to irrigated lands. However, the limited water availability, the severe climatic conditions and the increased need for good water quality for urban and industrial sector uses are leading to the urgent use of less water qualities (brackish water and recycled wastewater) for olive tree irrigation. The aim of this work was to asses the effects of long term irrigation with treated waste water (TWW) on the soil chemical properties, on olive tree growth and on oil quality characteristics. (Author)

  17. Durability and compressive strength of blast furnace slag-based cement grout for special geotechnical applications

    OpenAIRE

    Ortega Álvarez, José Marcos; Pastor Navarro, José Luis; Albaladejo Ruiz, Arturo; Sánchez Martín, Isidro; Climent, Miguel-Ángel

    2014-01-01

    Special foundations, most prominently micropiles and soil anchors, are frequently used in construction today. In Spain, the grout for these special technical applications is generally prepared with portland cement, although the codes and standards in place stipulate only the minimum compressive strength required, with no mention of cement type. Those texts also establish a range of acceptable water:cement ratios. In the present study, durability and compressive strength in cement grout prepar...

  18. Dynamics of elements in soil treated with increasing doses sewage sludge for instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    In this work the dynamics of the elements was analyzed The, Br, Ce, Co, Cr, Cs, Fe, Hf, La, In the, Sb, Sc, Sm, Ta, Th, U, Yb and Zn in a profile of a red-yellow latossolo, in the depths of 0-5, 5-10, 10-30 and 30-50 cm, and dose of the biosolid of 0, 25, 124 and 375 t ha-1, of the station of treatment of sewer of Barueri, Sao Paulo. The experiment was carried out in areas of 3,05 m2 in the times of 2,2; 4,0; 6,6; 14,3 and 21 months. For analysis of the elementary composition, it was used of the analysis technique by instrumental neutron activation analysis (INAA). The experiment was submitted under normal tropical conditions in a forest station in Itatinga, Sao Paulo, of the University of Sao Paulo. For better details, the factors depth, doses and times statistical analyses of the results of the elementary composition of the soil samples were made. For all the biossolid doses conditioned with polymeric and applied in the soil, the composition of 17 of the 18 elements in the soil were not altered, with exception for Cr in the studied times. The elements As, Br, Ce, Co, Fe, Hf, La, Sm, Ta, Th, U and Yb presented higher levels in the deepest layers of soil; already the elements Cr, In the, Sb and Zn presented higher concentrations in the superficial layers. (author)

  19. Survival, Pb-uptake and behaviour of three species of earthworm in Pb treated soils determined using an OECD-style toxicity test and a soil avoidance test

    Energy Technology Data Exchange (ETDEWEB)

    Langdon, Caroline J. [Department of Soil Science, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading, Berkshire, RG6 6DW (United Kingdom)]. E-mail: clangdon@uclan.ac.uk; Hodson, Mark E. [Department of Soil Science, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading, Berkshire, RG6 6DW (United Kingdom)]. E-mail: m.e.hodson@reading.ac.uk; Arnold, Rebecca E. [Department of Soil Science, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading, Berkshire, RG6 6DW (United Kingdom); Black, Stuart [Department of Archaeology, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading, Berkshire, RG6 6AB (United Kingdom)

    2005-11-15

    Mature (clitellate) Eisenia andrei Bouche (ultra epigeic), Lumbricus rubellus Hoffmeister (epigeic), and Aporrectodea caliginosa (Savigny) (endogeic) earthworms were placed in soils treated with Pb(NO{sub 3}){sub 2} to have concentrations in the range 1000 to 10 000 mg Pb kg{sup -1}. After 28 days LC50{sub -95%confidencelimit}{sup +95%confidencelimi}= {sup t} values were E. andrei5824{sub -361}{sup +898} mg Pb kg{sup -1}, L. rubellus2867{sub -193}{sup +145} mg Pb kg{sup -1} and A. caliginosa2747{sub -304}{sup +239} mg Pb kg{sup -1} and EC50s for weight change were E. andrei2841{sub -68}{sup +150} mg Pb kg{sup -1}, L. rubellus1303{sub -201}{sup +240} mg Pb kg{sup -1} and A. caliginosa1208{sub -206}{sup +212} mg Pb kg{sup -1}. At any given soil Pb concentration, Pb tissue concentrations after 28 days were the same for all three earthworm species. In a soil avoidance test there was no difference between the behaviour of the different species. The lower sensitivity to Pb exhibited by E. andrei is most likely due to physiological adaptations associated with the modes of life of the earthworms, and could have serious implications for the use of this earthworm as the species of choice in standard toxicological testing.

  20. ULTRA-LIGHTWEIGHT CEMENT

    International Nuclear Information System (INIS)

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Issues, Task 2: Review Russian Ultra-Lightweight Cement Literature, Task 3: Test Ultra-Lightweight Cements, and Task 8: Develop Field ULHS Cement Blending and Mixing Techniques. Results reported this quarter include: preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; summary of pertinent information from Russian ultra-lightweight cement literature review; laboratory tests comparing ULHS slurries to foamed slurries and sodium silicate slurries for two different applications; and initial laboratory studies with ULHS in preparation for a field job

  1. Characteristics and empirical formula of electrical resistivity of cement-solidified lead-contaminated soils%水泥固化铅污染土的电阻率特性与经验公式

    Institute of Scientific and Technical Information of China (English)

    章定文; 曹智国; 刘松玉; 陈蕾

    2015-01-01

    In order to explore the application potential of electrical resistivity method in the field of solidified heavy metal-contaminated soils, the artificial contaminated soils with five different lead contents are solidified using cement, and then their electrical resistivities and unconfined compressive strengths after various curing periods are tested. The relationship between the electrical resistivity and unconfined compressive strength is discussed. The test results show that the cement hydration reaction results in an increase of the electrical resistivity of solidified samples, but the electrical resistivity decreases with the increase of after-curing porosity, degree of saturation and lead content. A key parameter (nt·Pb100ew)/ (aw·T0.5) (e is the Euler's number) is proposed to comprehensively reflect the effects of the lead content, cement hydration reaction and dense state of soils on the electrical resistivity of solidified soils. The Archie's electrical resistivity formula is extended to solidified heavy metal-contaminated soils by replacing the porosity by the key parameter. There is a power function relationship between the strength and the electrical resistivity while the lead content of solidified soils is certain. The electrical resistivity method can be used as a non-destructive, economical and continuous way to evaluate the quality of solidified heavy metal-contaminated soils.%为探讨电阻率法在水泥固化重金属污染土性能评价中的应用潜能,室内配制人工铅污染土,采用水泥固化后测试其电阻率和无侧限抗压强度,分析固化土电阻率的变化规律,建立固化铅污染土的电阻率公式,并探讨电阻率与无侧限抗压强度的相关关系.试验结果表明,固化土电阻率随铅含量增大而减小,随着水泥掺入量和养护龄期的增加而增大,随着孔隙率和饱和度的减小而增大.提出了一个能够综合反映铅含量、水泥掺入量和养护龄期等因素对固化

  2. Ensaios de arrancamento e de empuxamento aplicados a taliscas de bambu encravadas em corpos-de-prova de solo-cimento Pull-out and push-in tests of bamboo splint embedded in soil-cement specimen

    Directory of Open Access Journals (Sweden)

    Wilza G. R. Lopes

    2002-12-01

    Full Text Available Neste trabalho, taliscas de bambu da espécie Dendrocalamus giganteus, engastadas em corpos-de-prova de solo-cimento, foram submetidas a ensaios de arrancamento (pull-out e de empuxamento (push-out a fim de se determinar sua resistência de aderência. Para esta finalidade, foi utilizado um solo-cimento feito a partir de um solo arenoso que continha aproximadamente 70% de areia. Corpos-de-prova de solo-cimento, de 15 cm de diâmetro e 30 cm de altura, foram moldados com 14% de cimento na umidade ótima de 10,7%. As taliscas de bambu foram preparadas com 2 cm de largura e comprimentos de 40, 50 e 60 cm, para o ensaio de arrancamento, e de 70 cm para o ensaio de empuxamento. Metade das taliscas foi deixada sem tratamento impermeabilizante e a outra metade foi revestida com emulsão asfáltica, impregnada com areia limpa grossa, para produzir uma superfície áspera e garantir melhor aderência com o solo-cimento. Os corpos-de-prova de solo-cimento com as taliscas de bambu engastadas, foram deixados a curar em câmara úmida, durante 28 d, antes de serem ensaiados. Ambos os ensaios foram realizados em uma máquina universal de ensaio adaptada, sendo as deformações medidas com um relógio comparador aferido, de sensibilidade igual a 0,01 mm. A resistência de aderência, quer fosse determinada pelo ensaio de arrancamento quer pelo ensaio de empuxamento, foi obtida dividindo-se a máxima carga verificada no ensaio pela área lateral da talisca de bambu efetivamente engastada no solo-cimento. Os melhores resultados foram obtidos sem aplicação de material impermeabilizante, para o ensaio de arrancamento, enquanto nenhuma diferença foi observada entre os dois tratamentos para o ensaio de empuxamento.In this study, Dendrocalamus giganteus bamboo splints (split culm embedded in soil-cement specimens were submitted to pull-out and push-in tests in order to determine its bonding strength. For this purpose a sandy soil was utilized. The 15.0 cm diameter

  3. Cytotoxicity evaluation of five different dual-cured resin cements used for fiber posts cementation

    Science.gov (United States)

    Dioguardi, M; Perrone, D; Troiano, G; Laino, L; Ardito, F; Lauritano, F; Cicciù, M; Muzio, L Lo

    2015-01-01

    Custom-cast posts and cores are usually used to treat endodontically treated teeth. However, several researches have underlined how these devices may be a much higher elastic modulus than the supporting dentine and the difference in the modulus could lead to stress concentrating in the cement lute, leading to failure. The role of the cement seems to play a fundamental role in order to transfer the strength during the chewing phases. Aim of this research is to record the rate of cytotoxicity of five different dual-cured resin cements used for fiber posts cementation. We tested the cytotoxicity of this five materials on MG63 osteoblast-like cells through two different methods: MTT ([3-4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide succinate) assay which tests for mitochondrial enzyme activity6 and xCELLigence® system. PMID:26309592

  4. Physical-Chemical Characterization of Soils Treated with Sewage Sludge Compost

    OpenAIRE

    Milda Radžiūtė; Audronė Matusevičiūtė

    2011-01-01

    Sewage dump is the main organic waste component accumulating in water treatment companies, and therefore the utilization of dump remains a burning issue. Fertilization is the most popular and cheapest way of using sewage dump a part of which is intended for agriculture in most European countries for composting purposes. Sewage dump or its compost are suitable for fertilizing the upper layers of the soil in cases the concentration of heavy metals is not greater than sanitarian standards can to...

  5. Use of electrokinetic and reactive barriers to treat heavy metals-contaminated soils

    OpenAIRE

    Spiga, Daniela

    2011-01-01

    The combined use of electrokinetic (EK) and reactive barrier (RB) of transformed red mud (TRM) (a by-product of bauxite refinement for alumina production) for the remediation of low permeability contaminated soils by chromium and arsenic was investigated. The combination of EK with RB is a possible way in order to enhance EK removal of Cr and As that are reported to be among the more difficult elements to remove by electrokinetics. The goal and the novelty of the research consi...

  6. Optimisation and adoption of slag based cement for conditioning of intermediate level alkaline radioactive liquid waste in CLEAR-V campaign

    International Nuclear Information System (INIS)

    The ILW is normally treated by resorcinol formaldehyde special type of resin. Another method for management of ILW is by conditioning in cement matrix. Various waste to cement ratios have been tried at lab and plant scale by taking slag based cement and ordinary portland cement. The cement waste products were evaluated for various properties. The final selected waste to cement ratio has been successfully adopted on the plant scale for conditioning of 140 m3 of ILW at SWMF. (author)

  7. Transfer of Cobalt-60 to plants from soils treated with sewage sludge

    International Nuclear Information System (INIS)

    The uptake of 60Co from soils fertilized with contaminated sewage sludge has been investigated under a variety of experimental conditions. A number of garden plots were prepared by thoroughly mixing sludge containing 60Co with farm soils from the Ottawa Valley. Edible plants were grown in the open on these plots under conditions approximating those in market gardens. The crops were harvested at maturity and were prepared for measurement of 60Co by drying portions of the roots, leaves, stems and fruit. The samples were counted on a large germanium detector which was capable of resolving 60Co from other gamma-emitting nuclides. Cobalt was readily taken up from contaminated sludge but was nonuniformly distributed in various parts of the plant. In general, the roots showed the highest levels while edible portions such as seeds and tubers had much lower concentrations. The uptake ratio, expressed as radioactivity in the sample to radioactivity in the soil, varied from 0.003 to 8 on a dry-weight basis. (author)

  8. Redistribution of Pb, Zn and Cu Fractions in Tailing Soils Treated with Different Extractants

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-Guo; WANG Xian-Hai; ZENG Guang-Ming; LI Xin; ZHOU Chun-Hua; FAN Ting; LI Yong-Li; YUAN Xin-Zhong

    2006-01-01

    The efficiency of EDTA, HNO3 and CaCl2 as extractants to remove Pb, Zn and Cufrom tailing soils without varying soil pH was investigated with distributions of Pb, Zn and Cu being determined before and after extraction using the sequential extraction procedure of the optimized European Community Bureau of Reference (BCR). Results indicated that EDTA and HNO3 were both effective extracting agents. The extractability of extractants for Pb and Zn was in the order EDTA > HNO3 > CaCl2, while for Cu it was HNO3 > EDTA > CaCl2. After EDTA extraction, the proportion of Pb, Zn and Cu in the four fractions varied greatly, which was related to the strong extraction and complexation ability. Before and after extraction with HNO3 and CaCl2, the percentages of Pb, Zn and Cu in the reducible, oxidizable and residual fractions changed little compared to the acid-extractable fraction. The lability of metal in the soil andthe kinds of extractants were the factors controlling the effects of metal extraction.

  9. Physical-Chemical Characterization of Soils Treated with Sewage Sludge Compost

    Directory of Open Access Journals (Sweden)

    Milda Radžiūtė

    2011-02-01

    Full Text Available Sewage dump is the main organic waste component accumulating in water treatment companies, and therefore the utilization of dump remains a burning issue. Fertilization is the most popular and cheapest way of using sewage dump a part of which is intended for agriculture in most European countries for composting purposes. Sewage dump or its compost are suitable for fertilizing the upper layers of the soil in cases the concentration of heavy metals is not greater than sanitarian standards can tolerate. The examinations were carried out using different waste dump rates from Vilnius water treatment facility in willow (Salix viminalis grown cultivated fields. The analysis of the soil was executed after one and two years following the fertilization process. The obtained results indicate that waste dump is a valuable organic fertilizer which contains small amounts of heavy metals. Separate heavy metals migrate from sewage sludge compost to plants differently. It was noted that the concentration of heavy metals in willows was greater (except for Pb and Cd than that in the soil.Article in Lithuanian

  10. Chemical properties of soils treated with biological sludge from gelatin industry

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Melo Guimarães

    2012-04-01

    Full Text Available The impact of agro-industrial organic wastes in the environment can be reduced when used in agriculture. From the standpoint of soil fertility, residue applications can increase the organic matter content and provide nutrients for plants. This study evaluated the effect of biological sludge from gelatin industry on the chemical properties of two Ultisols (loamy sand and sandy clay and an Oxisol (clay. The experiment lasted 120 days and was carried out in laboratory in a completely randomized design with factorial arrangement, combining the three soils and six biological sludge rates (0, 100, 200, 300, 400, and 500 m³ ha-1, with three replications. Biological sludge rates of up to 500 m³ ha-1 decreased soil acidity and increased the effective cation exchange capacity (CEC and N, Ca, Mg, and P availability, without exceeding the tolerance limit for Na. The increase in exchangeable base content, greater than the effective CEC, indicates that the major part of cations added by the sludge remains in solution and can be lost by leaching.

  11. Physical, Mineralogical, and Micromorphological Properities of Expansive Soil Treated at Different Temperature

    Directory of Open Access Journals (Sweden)

    Jian Li

    2014-01-01

    Full Text Available Different characterizations were carried out on unheated expansive soil and samples heated at different temperature. The samples are taken from the western outskirts of Nanning of Guangxi Province, China. In the present paper, the mineral and chemical composition and several essential physical parameters of unheated expansive soil are indicated by XRD and EDX analysis. Moreover, the structural transition and change of mechanical properties of samples heated in the range of room temperature to 140°C are proved by TG-DTA and SEM observation. The mean particle diameter, density, hydraulic behaviors, and bond strength also have been investigated. The results indicate that, along with the loss of free water, physical absorbed water, and chemically bound water, the microstructure experiences some obvious change. In addition, the particle size and density both will increase rapidly before 100°C and undertake a slow growth or decline when higher than 100°C. The hydraulic behaviors and strength performance of unheated samples and the one heated at 100°C are given out as well. All these researches play fundamental role in the pollution prevention, modification, and engineering application of expansive soil.

  12. ULTRA-LIGHTWEIGHT CEMENT

    International Nuclear Information System (INIS)

    The objective of this project is to develop an improved ultra-lightweigh cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems, Task 2: Review Russian Ultra-Lightweight Cement Literature, and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary surface pipe and intermediate casing cementing conditions historically encountered in the US and establishment of average design conditions for ULHS cements. Russian literature concerning development and use of ultra-lightweight cements employing either nitrogen or ULHS was reviewed, and a summary is presented. Quality control testing of materials used to formulate ULHS cements in the laboratory was conducted to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS. This protocol is presented and discussed. finally, results of initial testing of ULHS cements is presented along with analysis to establish cement performance design criteria to be used during the remainder of the project

  13. Clinical results of pedicle screws with cement augmentation for treating lumbar degenerative diseases in the elderly%椎弓根螺钉骨水泥强化修复老年腰椎退变的早期效果

    Institute of Scientific and Technical Information of China (English)

    陈荣国; 代凤雷; 欧先锋; 杨超; 钱建吉; 曾怿; 任家云; 虞泽龙

    2014-01-01

    背景:老年腰椎退变患者在手术中常面临椎弓根螺钉把持力不足情况,易发生脱钉、固定不牢靠等风险,如何增加螺钉的把持力成为研究的热点。目的:探讨使用椎弓根螺钉骨水泥强化方案治疗老年腰椎退变的早期临床效果。方法:选择2012年8月至2014年4月收治的患腰椎退行性疾病行腰椎内固定治疗的患者65例,根据修复方案分为2组,椎弓根螺钉内固定骨水泥强化组24例,常规椎弓根螺钉内固定组41例。比较两组患者的一般情况,采用目测类比评分法和日本矫形科学学会腰椎功能评分表对患者腰背疼痛及下肢神经功能恢复情况进行评估。结果与结论:65例患者均完成手术,获得随访,随访时间为3-20个月,随访中均行腰椎正侧位片X射线片,未发现螺钉松动、脱落、断裂、椎间隙高度丢失等情况。椎弓根螺钉内固定骨水泥强化组患者的手术出血量、住院时间与常规椎弓根螺钉内固定组差异无显著性意义(P>0.05),椎弓根螺钉内固定骨水泥强化组术后3,6个月日本矫形科学学会腰椎功能评分及术后3个月的目测类比评分均较常规椎弓根螺钉内固定组显著改善(P 0.05)。提示将骨水泥沿椎弓根螺钉钉道注入椎弓根及椎体,可达到螺钉骨水泥强化的目的,增加螺钉的把持力,重建腰椎的稳定性,取得了满意的近期疗效。%BACKGROUND:Elderly patients with degenerative lumbar degeneration often appear insufficient holding power of pedicle screw in spine surgery, which is prone to occur de-pinning and leads to insecure fixation. How to increase the holding power of screws has become a hot research. OBJECTIVE:To observe the early clinical effect of pedicle screws with cement augmentation for treating lumbar degenerative diseases in elderly patients. METHODS:A total of 65 old patients with lumbar degenerative diseases received a treatment

  14. Percutaneous bone cement refixation of aseptically loose hip prostheses: the effect of interface tissue removal on injected cement volumes

    Energy Technology Data Exchange (ETDEWEB)

    Malan, Daniel F. [Leiden University Medical Center, Department of Orthopaedics, Leiden (Netherlands); Delft University of Technology, Department of Intelligent Systems, Delft (Netherlands); Valstar, Edward R. [Leiden University Medical Center, Department of Orthopaedics, Leiden (Netherlands); Delft University of Technology, Department of Biomechanical Engineering, Delft (Netherlands); Nelissen, Rob G.H.H. [Leiden University Medical Center, Department of Orthopaedics, Leiden (Netherlands)

    2014-11-15

    To quantify whether injected cement volumes differed between two groups of patients who underwent experimental minimally invasive percutaneous cement injection procedures to stabilize aseptically loose hip prostheses. One patient group was preoperatively treated using gene-directed enzyme prodrug therapy to remove fibrous interface tissue, while the other group received no preoperative treatment. It was hypothesized that cement penetration may have been inhibited by the presence of fibrous interface tissue in periprosthetic lesions. We analyzed 17 patients (14 female, 3 male, ages 72-91, ASA categories 2-4) who were treated at our institution. Osteolytic lesions and injected cement were manually delineated using 3D CT image segmentation, and the deposition of injected cement was quantified. Patients who underwent preoperative gene-directed enzyme therapy to remove fibrous tissue exhibited larger injected cement volumes than those who did not. The observed median increase in injected cement volume was 6.8 ml. Higher cement leakage volumes were also observed for this group. We conclude that prior removal of periprosthetic fibrous interface tissue may enable better cement flow and penetration. This might lead to better refixation of aseptically loosened prostheses. (orig.)

  15. THE EFFECT OF REINFORCEMENT ON THE GBFS AND LIME TREATED MARINE CLAY FOR FOUNDATION SOIL BEDS

    Directory of Open Access Journals (Sweden)

    D. Koteswara Rao,

    2011-03-01

    Full Text Available India being peninsular country has large area coming under coastal region and also it has been the habitat for considerable percentage of population. The marine clays are generally found in the coastal region of West Bengal, Orissa, Andhra Pradesh, Tamilnadu, Kerala, Karnataka, Maharashtra and some parts of Gujarat. Marine or soft clays exists in these region are weak and deformative in nature. The present study deals with the strength characteristics of the marine clay collected from Kakinada Sea Port Ltd, Kakinada, A.P, India. The effect of lime on the strength characteristics of marine clay are studied in this investigation along with the reinforcement effect using geotextile as reinforcement and separator for the foundation soil bed.

  16. Hydrothermal processing of new fly ash cement

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, W.; Roy, D.M. (Materials Research Lab., Pennsylvania State Univ., University Park, PA (United States))

    1992-04-01

    The recent Mount Pinatubo volcanic eruption in the Philippines, in which at least 268 people died, shows that volcanic eruptions can be highly destructive. The eruption shot ash and debris over the countryside; six towns near the volcano faced a high risk of devastating mudslides, and nearly 2000 U.S. service members and their families were evacuated from two nearby military bases. However, this paper reports that not all the consequences of volcanic eruptions are bad. Under hydrothermal conditions, volcanic ash can be transformed into zeolitic tuff and, eventually, into clay minerals that constitute agricultural soils. The Materials Research Laboratory (MRL) has recently used some artificial pozzolanas (fly ash) that when mixed with lime, under hydrothermal conditions, also produced a new type of cementitious material. This was categorized as a new fly ash cement. The formation of a new hydrothermally treated wood-fiber-reinforced composite has also been demonstrated. It is apparent, however, that with respect to concerns about detailed knowledge of the reactivity of calcium silicate-based materials under hydrothermal conditions, the application of the technology far outweighs the understanding of the underlying principles of reactivity. It would seem that an understanding of reactions on the molecular level is just beginning, and that work on hydrothermal reactions is still a potentially lucrative area of research.

  17. Effect of Cement Replacement with Carbide Waste on the Strength of Stabilized Clay Subgrade

    Directory of Open Access Journals (Sweden)

    Muntohar A.S.

    2016-03-01

    Full Text Available Cement is commonly used for soil stabilization and many other ground improvement techniques. Cement is believed to be very good to improve the compressive and split-tensile strength of clay subgrades. In some application cement could be partly or fully replaced with carbide waste. This research is to study the effectiveness of the cement replacement and to find the maximum carbide waste content to be allowed for a clay subgrade. The quantities of cement replaced with the carbide waste were 30, 50, 70, 90, and 100% by its mass. The results show that replacing the cement with carbide waste decreased both the compressive and split tensile strength. Replacing cement content with carbide waste reduced its ability for stabilization. The carbide waste content should be less than 70% of the cement to provide a sufficient stabilizing effect on a clay subgrade.

  18. EXPERIMENTAL STUDY ON DYNAMIC CHARACTERISTICS OF COMPOSITE FOUNDATIONS OF RAMMED CEMENT-SOIL LOOP PILES WITH CFG CORES%CFG芯水泥土环组合桩复合地基动力特性试验研究

    Institute of Scientific and Technical Information of China (English)

    丁继辉; 冯俊辉; 张攀星; 全小娟

    2015-01-01

    For optimized pile foundation design,the concepts of cement-flyash-gravel pile (CFGP) and rammed cement-soil pile (RCSP) were combined in this study to form the rammed cement-soil loop pile with CFG cores (CFGCP-RCSLP).The static and dynamic characteristics of the CFGCP-RCSLP composite foundation were studied using in-situ tests.Test results show that with identical soil properties,pile length and pile spacing,the load-settlement curve of the CFGCP-RCSLP composite foundation demonstrates a clear linear relationship.The bearing capacity of the CFGCP-RCSLP composite foundation is 19.1% lower than the CFGP composite foundation,23.8% lower than that of the RCSP pile composite foundation,and 102% higher than a natural foundation.The blasting tests show that under same explosion energy and the arrangement of blast points,the dynamic characteristics of composite foundations are primarily related to soil properties,pile rigidity distribution and pilling load.The blast point location arrangement directly influences the distribution of peak acceleration along the pile body of CFGCP-RCSLP composite foundations,and the peak acceleration decreases significantly as the pilling load increases.%基于优化桩型的观点,将工法成熟的水泥粉煤灰碎石桩(简称CFGP)和夯实水泥土桩(简称RCSP)进行组合,设计CFG芯桩-水泥土环桩(简称CFGCP-RCSLP)组合桩复合地基,通过现场试验研究CFGCP-RCSLP组合桩复合地基的静力特性和动力特性.现场载荷试验表明,当土性、桩长、桩间距相同的情况下,CFGCP-RCSLP组合桩复合地基的荷载沉降曲线具有明显的线性关系,复合地基承载力比CFGP复合地基降低19.1%,比RCSP桩复合地基降低23.8%,比天然地基增加了102%.现场爆破试验表明,在爆炸能量、爆炸点位置相同条件下,复合地基的动力特性主要取决于土性、桩体刚度分布和堆载的大小.爆炸点的位置直接影响CFGCP-RCSLP组合桩复合地基中峰

  19. Basal respiration and stratification ratio in soil cultivated with citrus and treated with organic residues in the state of Sergipe

    Directory of Open Access Journals (Sweden)

    Juliana Augusta Moura

    2015-04-01

    Full Text Available The use of organic residues in the soil to improve its quality, provide nutrients to plant growth and increase carbon storage is an ancient practice, but little is known about the application of laminar composting in citrus orchards. The objective of this study was to evaluate the microbial activity through microbial respiration, and the different rates stratification of some variables related to this attribute of an Ultisol cultivated with citrus and treated with organic waste in the state of Sergipe. Soil samples were collected in the layers 0-5 cm, 5-10 cm, and 10-15 cm in a citrus orchard (Citrus sinensis, L. Osbeck under different treatments 1. Layering organic residue (crop wastes placed in layers under the plant canopy 2. Layering organic residue + NPK (the same as described in iten 1 + NPK; 3. Humus (Humified organic compost applied under the plant canopy; 4. Humus + NPK (the same as described in iten 3 + NPK; 5. Control + NPK (plant canopy was kept free of residues, + NPK application; 6. Control – NPK (plant canopy was kept free of residues, without application of NPK, with three replications. It has been found that the use of the organic residue in the plant canopy increased microbial respiration rate and total organic matter content, as well as an increase in some chemical attributes as pH, P, Ca and Mg in all treatments compared the control. The ratio stratification was effective to evaluate the influence of different management practices between depths demonstrating an improvement in microbial activity by more practical conservation treatments and indicating that the use of Humus, humus + NPK and alternate layering residues + NPK were the most effective in increasing the organic matter content in the soil

  20. Bioavailability and influence of ¹⁴C-carbofuran on Eisenia andrei avoidance, growth and reproduction in treated natural tropical soils.

    Science.gov (United States)

    Ferreira, Regina C B; Papini, Solange; de Andréa, Mara M

    2015-01-01

    The bioavailability of carbofuran to the compost worms Eisenia andrei and the influence of its residual amounts on the avoidance, reproduction and growth of this species were studied in two natural tropical soils: a Typic Humaquept (GM) and a Typic Hapludox (LVD), as indicated by the Brazilian environmental authorities for ecotoxicological tests. The worms avoided the soil LVD treated with different doses of carbofuran. The pesticide also affected the production of juvenile specimens in both soils, but cocoon production was reduced only in the GM soil. The earthworms' growth and weight loss were affected by carbofuran (2,2-dimethyl-2,3-dihydro-1-1-benzofuran-7-yl methylcarbamate. CAS number 1563-66-2) only in the LVD and the mortality detected at 56 days of contact with the treated soils was not statistically significant in both of them. Fourteen days after the soil treatment with(14) c-carbofuran, most residues detected in the soils were bound residues (approximately 36% and 30% in the GM and LVD, respectively) and neither mortality nor bioaccumulation was detected in the earthworms, even with absorptions of 13% and 43%, respectively. The LVD soil has lower organic matter content, and the effects of carbofuran on different aspects of the earthworms' life were more pronounced in this soil, most likely due to the higher bioavailability of the pesticide in the soil solution. The results for carbofuran clearly demonstrate that even small quantities of residues do not assure lack of toxicity. They also make evident the necessity of studying the effects of pesticides in natural agricultural soils. Furthermore, as the bound residues and the earthworm contamination are not detected by conventional techniques, they are not taken into account and may be underestimated on environmental risk assessments. PMID:25714458

  1. Bioavailability and influence of ¹⁴C-carbofuran on Eisenia andrei avoidance, growth and reproduction in treated natural tropical soils.

    Science.gov (United States)

    Ferreira, Regina C B; Papini, Solange; de Andréa, Mara M

    2015-01-01

    The bioavailability of carbofuran to the compost worms Eisenia andrei and the influence of its residual amounts on the avoidance, reproduction and growth of this species were studied in two natural tropical soils: a Typic Humaquept (GM) and a Typic Hapludox (LVD), as indicated by the Brazilian environmental authorities for ecotoxicological tests. The worms avoided the soil LVD treated with different doses of carbofuran. The pesticide also affected the production of juvenile specimens in both soils, but cocoon production was reduced only in the GM soil. The earthworms' growth and weight loss were affected by carbofuran (2,2-dimethyl-2,3-dihydro-1-1-benzofuran-7-yl methylcarbamate. CAS number 1563-66-2) only in the LVD and the mortality detected at 56 days of contact with the treated soils was not statistically significant in both of them. Fourteen days after the soil treatment with(14) c-carbofuran, most residues detected in the soils were bound residues (approximately 36% and 30% in the GM and LVD, respectively) and neither mortality nor bioaccumulation was detected in the earthworms, even with absorptions of 13% and 43%, respectively. The LVD soil has lower organic matter content, and the effects of carbofuran on different aspects of the earthworms' life were more pronounced in this soil, most likely due to the higher bioavailability of the pesticide in the soil solution. The results for carbofuran clearly demonstrate that even small quantities of residues do not assure lack of toxicity. They also make evident the necessity of studying the effects of pesticides in natural agricultural soils. Furthermore, as the bound residues and the earthworm contamination are not detected by conventional techniques, they are not taken into account and may be underestimated on environmental risk assessments.

  2. Plant uptake of depleted uranium from manure-amended and citrate treated soil.

    Science.gov (United States)

    Sevostianova, Elena; Lindemann, William C; Ulery, April L; Remmenga, Marta D

    2010-08-01

    Six plant species were tested for their ability to accumulate depleted uranium in their above-ground biomass from deployed munitions contaminated soil in New Mexico. In greenhouse experiments, Kochia (Kochia scoparia L. Schrad.) and pigweed (Amaranthus retroflexus L) were grown with steer manure added at rates of 22.4, 44.8, and 89.6 Mg ha(-1). Citric acid and glyphosate (N-(phosphonomethyl) glycine) applied at the end of the growing season increased DU concentrations from 2.5 to 17 times. Leaf and stem DU concentrations in kochia increased from 17.0 to 41.9 mg kg(-1) and from 3.5 to 18.0 mg kg(-1), respectively. In pigweed, leaf and stem DU concentrations increased from 1.0 to 17.3 and from 1.0 to 4.7 mg kg(-1), respectively. Manure generally decreased or had no effect on DU uptake. The effect of citric acid and ammonium citrate on DU uptake by kochia, sunflower (Helianthus annuus L), and sweet corn (Zea mays L) was also studied. Ammonium citrate was just as effective in enhancing DU uptake as citric acid. This implies that the citrate ion is more important in DU uptake and translocation than the solubilization of DU through acidification. In both experiments, leaves had higher DU concentrations than stems. PMID:21166280

  3. Tympanoplasty with ionomeric cement

    DEFF Research Database (Denmark)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    of > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy...

  4. Desiccation-Induced Volumetric Shrinkage of Compacted Metakaolin-Treated Black Cotton Soil for a Hydraulic Barriers System

    Science.gov (United States)

    Moses, George; Peter, Oriola F. O.; Osinubi, Kolawole J.

    2016-03-01

    Black cotton soil treated with up to 24% metakaolin (MCL) content was prepared by molding water contents of -2, 0, 2, 4 and 6% of optimum moisture content (OMC) and compacted with British Standard Light (BSL) and West African Standard (WAS) or `Intermediate' energies. The specimens were extruded from the compaction molds and allowed to air dry in a laboratory in order to assess the effect of desiccation-induced shrinkage on the compacted mix for use as a hydraulic barrier in a waste containment application. The results recorded show that the volumetric shrinkage strain (VSS) values were large within the first 10 days of drying; the VSS values increased with a higher molding of the water content, relative to the OMC. The VSS generally increased with a higher initial degree of saturation for the two compactive efforts, irrespective of the level of MCL treatment. Generally, the VSS decreased with an increasing MCL content. Only specimens treated with a minimum 20% MCL content and compacted with the WAS energy satisfied the regulatory maximum VSS of 4% for use as a hydraulic barrier.

  5. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2002-01-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

  6. Experimental Study on the Feasibility of Using Water Glass and Aluminum Sulfate to Treat Complications in High Liquid Limit Soil Subgrade

    Directory of Open Access Journals (Sweden)

    Wen-hui Zhang

    2015-01-01

    Full Text Available The feasibility of using water glass and aluminum sulfate to treat high liquid limit soil subgrade diseases is studied through laboratory experiments, and the following results were observed. After improving the high liquid limit clay with water glass and aluminum sulfate, the liquid limit decreases, the plastic limit increases, and the plasticity index decreases. Compared with untreated soil, the clay content of the improved soil decreases, while the silt and coarse contents increase. The absolute and relative expansion rates of the improved soil are both lower than those of the untreated soil. With the same number of dry and wet cycles, the decreased degrees of cohesion and internal friction angle of the improved soil are, respectively, one-half and one-third of those of the untreated soil. After three dry and wet cycles, the California bearing ratio (CBR of the untreated soil does not meet the requirements of specifications. However, after being cured for seven days and being subjected to three dry and wet cycles, the CBR of the improved soil, with 4% water glass solution and 0.4% aluminum sulfate, meets the requirements of specifications.

  7. [Mitigation of nitrous oxide emissions in vegetable system by treating soil with dicyandiamide, a nitrification inhibitor].

    Science.gov (United States)

    Qiu, Wei-Hong; Liu, Jin-Shan; Hu, Cheng-Xiao; Tan, Qi-Ling; Sun, Xue-Cheng; Hu, Zhen-Lan

    2011-11-01

    Undisturbed soil monolith lysimeter was used to investigate the effectiveness of DCD (dicyandiamide) in reducing N2O emissions in vegetable (Chinese cabbage and pepper) field. Results showed that DCD significantly reduced total N2O emission in vegetable field. Total N2O emissions from the urea treatment without DCD reached 0.215 kg x hm(-2) for Chinese cabbage, and it reduced to 0.109 kg x hm(-2), equivalent to a 49.3% reduction. The total N2O emissions for pepper were much higher compared with those for Chinese cabbage. The total N2O emitted from the urea treatment was 2.32 kg x hm(-2) (without DCD) and it was reduced to 1.14 kg x hm(-2) with DCD application, representing a 50.9% reduction. In the control treatments where no urea was applied, the daily N2O flux was very low and it never exceeded 9 microg x (m2 x h) (-1) for Chinese cabbage and 22 microg x (m2 x h) (-1) for pepper, respectively, but DCD also reduced N2O emissions (33.5% for Chinese cabbage and 33.4% for pepper). In addition, the urea-N emission factor (EF) was 0.15%, 0.99% for Chinese cabbage and pepper without DCD, respectively, and it was reduced to 0.07%, 0.52% when DCD was applied. These results demonstrated the potential of using nitrification inhibitors (DCD) to mitigate N2O emissions in vegetable system. PMID:22295611

  8. Arthroscopic Burring of Exposed Cement Following Curettage and Cavity Filling Cementation for Chondroblastoma of the Proximal Tibia

    OpenAIRE

    Park, Jong-Hoon; Chae, In-Jung; Han, Seung-Beom; Lee, Dae-Hee

    2015-01-01

    Chondroblastoma of the proximal tibia is difficult to treat because of its epiphyseal predilection. This condition can be treated by curettage, which results in immediate restoration of stability and a reduced recurrence rate, followed by cement filling of the bone defect. Nevertheless, contact with cement can damage articular cartilage, potentially leading to severe knee osteoarthritis. Most previous reports regarding this complication described patients with giant cell tumors of the proxima...

  9. Assessment of intermittently loaded woodchip and sand filters to treat dairy soiled water.

    Science.gov (United States)

    Murnane, J G; Brennan, R B; Healy, M G; Fenton, O

    2016-10-15

    Land application of dairy soiled water (DSW) is expensive relative to its nutrient replacement value. The use of aerobic filters is an effective alternative method of treatment and potentially allows the final effluent to be reused on the farm. Knowledge gaps exist concerning the optimal design and operation of filters for the treatment of DSW. To address this, 18 laboratory-scale filters, with depths of either 0.6 m or 1 m, were intermittently loaded with DSW over periods of up to 220 days to evaluate the impacts of depth (0.6 m versus 1 m), organic loading rates (OLRs) (50 versus 155 g COD m(-2) d(-1)), and media type (woodchip versus sand) on organic, nutrient and suspended solids (SS) removals. The study found that media depth was important in contaminant removal in woodchip filters. Reductions of 78% chemical oxygen demand (COD), 95% SS, 85% total nitrogen (TN), 82% ammonium-nitrogen (NH4N), 50% total phosphorus (TP), and 54% dissolved reactive phosphorus (DRP) were measured in 1 m deep woodchip filters, which was greater than the reductions in 0.6 m deep woodchip filters. Woodchip filters also performed optimally when loaded at a high OLR (155 g COD m(-2) d(-1)), although the removal mechanism was primarily physical (i.e. straining) as opposed to biological. When operated at the same OLR and when of the same depth, the sand filters had better COD removals (96%) than woodchip (74%), but there was no significant difference between them in the removal of SS and NH4N. However, the likelihood of clogging makes sand filters less desirable than woodchip filters. Using the optimal designs of both configurations, the filter area required per cow for a woodchip filter is more than four times less than for a sand filter. Therefore, this study found that woodchip filters are more economically and environmentally effective in the treatment of DSW than sand filters, and optimal performance may be achieved using woodchip filters with a depth of at least 1

  10. The effects of Paenibacillus polymyxa E681 on antifungal and crack remediation of cement paste.

    Science.gov (United States)

    Park, Sung-Jin; Park, Seung-Hwan; Ghim, Sa-Youl

    2014-10-01

    This study investigated the antifungal effects of cement paste containing Paenibacillus polymyxa E681 against Aspergillus niger, a deleterious fungus commonly found in cement buildings and structures. To test the antifungal effects, cement paste containing P. polymyxa E681 was neutralized by CO2 gas, and the fungal growth inhibition was examined according to the clear zone around the cement specimen. In addition to the antifungal effects of the cement paste added with bacteria, calcium crystal precipitation of P. polymyxa E681 was examined by qualitative and quantitative analyses. The cement paste containing P. polymyxa E681 showed strong antifungal effects but fusA mutant (deficient in fusaricidin synthesis) showed no antifungal activity. Crack sealing of the cement paste treated with P. polymyxa E681 was captured by light microscope showed fungal growth inhibition and crack repairing in cement paste. PMID:24824950

  11. Study on mechanical behaviors of interface with cemented soil slurry between gravel and concrete by simple shear tests%水泥土泥皮下土与结构接触面的单剪特性

    Institute of Scientific and Technical Information of China (English)

    彭凯; 朱俊高; 冯树荣; 蔡昌光; 朱晟

    2013-01-01

    The mechanical behaviors of the interface between coarse-grained soil and concrete are investigated by simple shear tests under conditions of cemented soil slurry (clay mixed with cement grout).The results show that the relation curve between shear stress and shear strain appears stress-strain softening and shear dilatation is significant.The point of peak strength and the position when the shear dilatation occurs are related to normal stress.In addition,shear dilatation occurs before the shear stress reaches peak value.In shear failure state,with the same height,the shear displacement increases as the normal stress increases.While with the same normal stress and at the same height,the shear displacement increases as the concrete content increases.A particle flow model of simple shear test between interface between coarse-grained soil and concrete is constructed by PFC (particle flow code).The disturbed height of the sample and the main influence factors are determined by analyzing the laws of particle motion at different heights inside the sample.The PFC results show disturbed height of the sample is related to maximum particle diameter of the soil,normal stress and roughness of the interface (with or without slurry) etc.In terms of the coarse-grained soil,the shear displacement is significant in the area which is close to the interface and about 3-4 times of the maximum particle diameter,and informed the obvious shear band.Further,the thickness of the interface can be regarded as the value.%采用大型单剪仪进行粗粒土与混凝土接触面在水泥土泥皮(粘土中掺入水泥)条件下的剪切试验,揭示泥皮条件下接触面的力学特性与机理.试验结果表明,峰值强度以及剪胀发生所对应的位置与法向应力大小有关,峰值强度所对应的剪应变滞后于产生剪胀的位置.剪切破坏时,在同一高度处,法向应力越大,切向位移也越大;同样的法向应力及高度处,切向位移随水泥含

  12. Zinc fractionation in the rhizosphere of wheat (Triticum aestivum L.) plant in soils treated with sewage sludge

    OpenAIRE

    Hosseinpur A. R.; Motaghian H. R.

    2013-01-01

    Rhizosphere is a microbiosphere and has quite different chemical, physical and biological properties from bulk soils. A greenhouse experiment was performed to compare fractionation of Zinc (Zn) between rhizosphere and bulk soils amended with sewage sludge (1% w/w of sewage sludge to soil). Fractions of Zn were determined in two subsamples (rhizosphere and bulk soils). The results indicated concentration of Zn-fractions (except carbonates-associated) in the rhizosphere soils were significantly (p

  13. Performance of cemented coal gangue backfill

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qin-li; WANG Xin-min

    2007-01-01

    Possibility of cemented gangue backfill was studied with gangue of Suncun Coal Mine, Xinwen Coal Group, Shandong,and fly ash of nearby thermal power plant, in order to treat enormous coal gangue on a large scale and to recovery safety coal pillars.The results indicate that coal gangue is not an ideal aggregate for pipeline gravity flow backfill, but such disadvantages of gangue as bad fluidity and serious pipe wear can be overcome by addition of fly ash. It is approved that quality indexes such as strength and dewatering ratio and piping feature of slurry can satisfy requirement of cemented backfill if mass ratio of cement to fly ash to gangue higher middle and long term comprehensive strength.

  14. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2003-01-31

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

  15. ANIMAL PERFORMANCE, CARCASS QUALITY, AND TISSUE RESIDUES WITH BEEF STEERS FED FORAGE SORGHUM SILAGES GROWN ON SOIL TREATED WITH LIQUID DIGESTED SLUDGE

    Science.gov (United States)

    Processed sewage sludges are a renewable resource which have potential as a fertilizer material on agricultural land. Forage sorghum (Sorghum bicolor) silages, grown on soil treated with Pensacola liquid digested sludge (LDS) turned under prior to planting, were fed as the main i...

  16. POZZOLAN AND CEMENTS WITH POZZOLAN

    OpenAIRE

    Kaplan, Hasan; Hanifi BİNİCİ

    1995-01-01

    Cement, one of the basic material of construction engineering, has an important place in view of strength and cost of structures. Cement consumption is increasing parallel to development of building construction sector. For cement producers, minimal cost is desired by using new and economical material sources. On the other hand, the controllers and contractors need cheaper, safer and higher strength materials. From this respect cement industry tends to use cement with pozzolan. In Türkiye, ce...

  17. Expansion control for cementation of incinerated ash

    International Nuclear Information System (INIS)

    A method, in which incinerated ash is solidified with a cement material, has been developed to dispose of radioactive incinerated ash waste. A small amount of metallic Al, which was not oxidized in the incineration, existed in the ash. When such ash was mixed with a cement material and water, alkaline components in the ash and the cement were dissolved in the mixing water and then metallic Al reaction with the alkaline compounds resulted in generation of H2. Because the H2 generation began immediately just after the mixing, H2 bubbles pushed up the mixed grout material and an expanded solidified form was obtained. The expansion leads to lowering the strength of the solidified form and making harmful void. In this study, we tried to control H2 generation from the reaction of metallic Al in the cementation by means of following two methods, one was a method to let metallic Al react prior to the cementation and the other was a method to add an expansion inhibitor that made an oxide film on the surface of metallic Al. In the pre-treatment, the ash was soaked in water in order to let metallic Al react with it, and then the ash with the immersion solution was dried at 105 Celsius degrees. The pre-treated ash was mixed with an ordinary portland cement and water. The inhibitor of lithium nitrite, sodium nitrite, phosphoric acid, or potassium dihydrogen phosphate was added at the mixing process. The solidified forms prepared using the pre-treated ash and lithium nitrite were not expanded. Phosphoric acid and sodium nitrite were effective for expansion control, but potassium dihydrogen phosphate did not work. (authors)

  18. Corrosion-resistant Foamed Cements for Carbon Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Gill, S.; Pyatina, T., Muraca, A.; Keese, R.; Khan, A.; Bour, D.

    2012-12-01

    The cementitious material consisting of Secar #80, Class F fly ash, and sodium silicate designed as an alternative thermal-shock resistant cement for the Enhanced Geothermal System (EGS) wells was treated with cocamidopropyl dimethylamine oxide-based compound as foaming agent (FA) to prepare numerous air bubble-dispersed low density cement slurries of and #61603;1.3 g/cm3. Then, the foamed slurry was modified with acrylic emulsion (AE) as corrosion inhibitor. We detailed the positive effects of the acrylic polymer (AP) in this emulsion on the five different properties of the foamed cement: 1) The hydrothermal stability of the AP in 200 and #61616;C-autoclaved cements; 2) the hydrolysis-hydration reactions of the slurry at 85 and #61616;C; 3) the composition of crystalline phases assembled and the microstructure developed in autoclaved cements; 4) the mechanical behaviors of the autoclaved cements; and, 5) the corrosion mitigation of carbon steel (CS) by the polymer. For the first property, the hydrothermal-catalyzed acid-base interactions between the AP and cement resulted in Ca-or Na-complexed carboxylate derivatives, which led to the improvement of thermal stability of the AP. This interaction also stimulated the cement hydration reactions, enhancing the total heat evolved during cement’s curing. Addition of AP did not alter any of the crystalline phase compositions responsible for the strength of the cement. Furthermore, the AP-modified cement developed the porous microstructure with numerous defect-free cavities of disconnected voids. These effects together contributed to the improvement of compressive-strength and –toughness of the cured cement. AP modification of the cement also offered an improved protection of CS against brine-caused corrosion. There were three major factors governing the corrosion protection: 1) Reducing the extents of infiltration and transportation of corrosive electrolytes through the cement layer deposited on the underlying CS

  19. Experimental evaluation of cement materials for solidifying sodium nitrate

    International Nuclear Information System (INIS)

    Low-level liquid waste containing sodium nitrate is planned to be transformed to salt block by evaporation with sodium borate in the Low-level Waste Treatment Facility (LWTF), then salt block will be stored temporally. It should be important to investigate the method how to treat these liquid waste suitable to final disposal criteria that will be settled in future. Cement solidification is one of promising candidates because it has been achieved as the solidification material for the shallow land disposal. The research was conducted to evaluate applicability of various cement materials to solidification of sodium nitrate. The following cements were tested. Ordinary Portland Cement (OPC). Portland Blast-furnace Slag Cement; C type (PBFSC). Alkali Activated Slag Cement (AASC, supplied by JGC). The test results are as follows; (1) AASC is characterized by a high sodium nitrate loading (-70 wt%) compared with other types of cement material. High fluidity of the cement paste, high strength after solidification, and minimization of free water on the cement paste are achieved under all test conditions. (2) OOPC and PBFSC produced free water on the cement paste in the early days and delayed the hardening period. 3 or more days are required to harden evan with 30 wt% content of sodium nitrate. (3) Though PBFSC contains blast furnace slag similar to AASC, there is no advantage prior to OPC. To design an ideal cement conditioning system for sodium nitrate liquid waste in the LWTF, the further studies are necessary such as the simulated waste test, Kd test, pilot test, and layout design. (author)

  20. Nitrate and ammonium transformation and redox potential changes in organic soil (Eutric Histosol) treated with municipal waste water

    OpenAIRE

    U. Kotowska; T. Włodarczyk

    2006-01-01

    The dynamics of nitrogen forms in soil irrigated with municipal waste water was studied in order to determine its effect on soil redox potential. The soil (Eutric Histosol) was planted with a mixture of grasses, and irrigated 10 times per year with waste water purified by a two-step (mechanical and biological) treatment with a dose optimal for the plants, or doubled. Simultaneously, control soil (not flooded) with plant vegetation was studied. It was found that redox potential was influenced ...

  1. Assessing the bioavailability of dissolved organic phosphorus in pasture and cultivated soils treated with different rates of nitrogen fertiliser

    NARCIS (Netherlands)

    McDowell, R.W.; Koopmans, G.F.

    2006-01-01

    A proportion of dissolved organic phosphorus (DOP) in soil leachates is readily available for uptake by aquatic organisms and, therefore, can represent a hazard to surface water quality. A study was conducted to characterise DOP in water extracts and soil P fractions of lysimeter soils (pasture befo

  2. Root-Zone Redox Dynamics - In Search for the Cause of Damage to Treated-Wastewater Irrigated Orchards in Clay Soils

    Science.gov (United States)

    Yalin, David; Shenker, Moshe; Schwartz, Amnon; Assouline, Shmuel; Tarchitzky, Jorge

    2016-04-01

    Treated wastewater (TW) has become a common source of water for agriculture. However recent findings raise concern regarding its use: a marked decrease (up to 40%) in yield appeared in orchards irrigated with TW compared with fresh water (FW) irrigated orchards. These detrimental effects appeared predominantly in orchards cultivated in clay soils. The association of the damage with clay soils rather than sandy soils led us to hypothesize that the damage is linked to soil aeration problems. We suspected that in clay soils, high sodium adsorption ratio (SAR) and high levels of organic material, both typical of TW, may jointly lead to an extreme decrease in soil oxygen levels, so as to shift soil reduction-oxidation (redox) state down to levels that are known to damage plants. Two-year continuous measurement of redox potential, pH, water tension, and oxygen were conducted in the root-zone (20-35 cm depth) of avocado trees planted in clay soil and irrigated with either TW or FW. Soil solution composition was sampled periodically in-situ and mineral composition was sampled in tree leaves and woody organs biannually. In dry periods the pe+pH values indicated oxic conditions (pe+pH>14), and the fluctuations in redox values were small in both TW and FW plots. Decreases in soil water tension following irrigation or rain were followed by drops in soil oxygen and pe+pH values. TW irrigated plots had significantly lower minimum pe+pH values compared with FW-irrigated plots, the most significant differences occurred during the irrigation season rather than the rain season. A linear correlation appeared between irrigation volume and reduction severity in TW-irrigated plots, but not in the FW plots, indicating a direct link to the irrigation regime in TW-irrigated plots. The minimum pe+pH values measured in the TW plots are indicative of suboxic conditions (9soil solution and in

  3. Novorossiysk agglomeration landscapes and cement production: geochemical impact assessment

    Science.gov (United States)

    Alekseenko, A. V.; Pashkevich, M. A.

    2016-09-01

    The article deals with assessing the environmental impact of marl mining and cement production in Novorossiysk city (Krasnodar krai, Russia). The existing methods of studying the environmental effects caused by the cement industry have been reviewed. Soil and aquatic vegetation sampling has been carried out and the gross concentration of metals in the samples has been defined. The research has been conducted in the certified and accredited laboratory using emission spectral analysis. The external control has been carried out via X-ray fluorescence analysis. Based on the collected data, main chemical pollutants in soil cover and water area near the cement plant have been identified. The contaminants released by urban enterprises and motor vehicle emissions, as well as fugitive dust from dumps and the cement factory, lead to multi-element lithogeochemical anomaly at geochemical barriers in soils. Accumulation of pollutants in soil depends on the type of land use and the area relief. The most contaminated aquatic landscapes have been identified in the inner bay. According to this information, the technical proposals can be prepared for environmental safety management in strongly polluted city areas, as well as for the reclamation design in the areas currently experiencing the negative impact of cement production.

  4. The Influence of Abutment Surface Treatment and the Type of Luting Cement on Shear Bond Strength between Titanium/Cement/Zirconia

    Directory of Open Access Journals (Sweden)

    Beata Śmielak

    2015-01-01

    Full Text Available Objectives. The objectives of this study were to evaluate the shear bond strength of zirconia cylinders on a modified titanium surface using different luting cement types. Material and Methods. Eighty titanium disks were divided into two groups (n=40, which were treated with either grinding or a combination of sandblasting and grinding. Then, each group was subdivided into 4 groups (n=10 and the disks were bonded to disks of sintered zirconia using one of four cement types (permanent: composite cement; temporary: polycarboxylate cement, zinc-oxide-eugenol cement, and resin cement. Shear bond strength (SBS was measured in a universal testing machine. Fracture pattern and site characteristic were recorded. A fractographic analysis was performed with SEM. The chemical analysis of the composition of the fractures was performed using energy-dispersive X-ray spectroscopy (EDS. The results of the experiment were analyzed with two-way analysis of variance and Tukey post hoc test. Results. The highest mean values of SBS were achieved when grinding was combined with sandblasting and when composite cement was used (18.18 MPa. In the temporary cement group, the highest mean values of SBS were for polycarboxylate cement after grinding (3.57 MPa. Conclusion. The choice of cement has a crucial influence on the titanium-cement-zirconia interface quality.

  5. EVALUATION OF CHEMICALS INCORPORATED WOOD FIBRE CEMENT MATRIX PROPERTIES

    Directory of Open Access Journals (Sweden)

    MST. SADIA MAHZABIN

    2013-08-01

    Full Text Available Wood fibre cement (WFC boards are well established commercially and widely used in many developed countries. The combination of the properties of two important materials, i.e., cement, and previously treated fibrous materials like wood or agricultural residues; which made up the board, contributed in the performance of the board as building material. In this work, the WFC matrix (WFCM samples are produced to determine the physical properties of WFCM such as the density and water absorption. The wood fibres are incorporated/treated with three different chemical additives; calcium formate (Ca(HCOO2, sodium silicate (Na2.SiO3 and magnesium chloride (MgCl2 prior to mixing with cement. The mechanical properties of the WFCM, with or without chemicals treatment of fibres, such as the compressive strength and flexural strength are evaluated. Three wood/cement ratios (50:50, 40:60, 30:70 are used and the percentages of water and accelerator were 80% and 3% based on the cement weight, respectively. Three moisture-conditioned samples; accelerated aging, dry and wet conditions are used for flexural test. The results reveal that the wood/cement ratio, chemical additives and moisture content had a marked influence on the physical and mechanical properties of the matrix. Finally, it has been shown that the 40:60 wood/cement ratio samples with prior chemicals treatment of the fibres that undergo accelerated aging conditioning achieve higher strength then dry and wet-conditioned boards.

  6. CONSTRUCTION AND DEMOLITION WASTE USE IN SOILCEMENT = APLICAÇÃO DO RESÍDUO DE CONSTRUÇÃO E DEMOLIÇÃO EM SOLO – CIMENTO

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Nobrega

    2005-01-01

    Full Text Available The generation of Construction and Demolition Wastes (CDW is a hugeenvironmental problem. In Piracicaba-SP, approximately 620 tons of these wastes are generated every day. This problem results in several environmental damages such as: irregular placing of wastes accumulating trash that attract animals capable to transmit illness; rubble on public roads and on streams that affect draining and stability on hills; degradation of urban visual; reduction of shelf-life of the levellings and nonrenewable mineral sources. Municipalities try to attend CONAMA, (2002 Resolution 307 requirements, undertaking actions to re-use CDW as aggregate forpaving, closing of ditches and producing concrete blocks. There is, however, the necessity to use it in bigger scale, enabling these materials to become feasible economical alternatives. Therefore, it is proposed to use it as an aggregate on soilcement composite. Physical, technological and chemical properties, of mixtures containing recycled CDW and soil in different proportions, were tested. It was noticed that those mixtures with 50%, 75% and 100% of CDW attend technological specifications for the use as soil-cement. As far as the chemical aspects are concerned, the use of recycled CDW as aggregate in the soil-cement showed to be feasible and efficient in the encapsulating process of the contaminants. = A geração de resíduos de construção e demolição constitui um grande problema ambiental. Em Piracicaba, SP, são geradas aproximadamente 620 toneladas/dia deste resíduo. O problema acarreta diversos prejuízos ambientais, tais como: disposição irregular dos resíduos agregando lixo e atraindo animais transmissores de doenças; entulhos em vias públicas e córregos afetando a drenagem e a estabilidade de encostas; degradação visual urbana; redução da vida útil de aterros e de recursos minerais não renováveis. Os municípios buscam atender às exigências da Resolução 307 (CONAMA, 2002

  7. [Comparison of fixation effects of heavy metals between cement rotary kiln co-processing and cement solidification/stabilization].

    Science.gov (United States)

    Zhang, Jun-li; Liu, Jian-guo; Li, Cheng; Jin, Yi-ying; Nie, Yong-feng

    2008-04-01

    Both cement rotary kiln co-processing hazardous wastes and cement solidification/stabilization could dispose heavy metals by fixation. Different fixation mechanisms lead to different fixation effects. The same amount of heavy metal compounds containing As, Cd, Cr, Cu, Pb, Zn were treated by the two kinds of fixation technologies. GB leaching test, TCLP tests and sequential extraction procedures were employed to compare the fixation effects of two fixation technologies. The leached concentration and chemical species distribution of heavy metals in two grounded mortar samples were analyzed and the fixation effects of two kinds of technologies to different heavy metals were compared. The results show the fixation effect of cement rotary kiln co-processing technology is better than cement solidification/stabilization technology to As, Pb, Zn. Calcinations in cement rotary kiln and then hydration help As, Pb, Zn contained in hazardous wastes transform to more steady chemical species and effectively dispose these heavy metals compounds. Cr3+ is liable to be converted to much more toxic and more mobile Cr6+ state in cement rotary kiln. And so Cr wastes are more fit for treatment by cement solidification/stabilization technology. The work could provide a basis when choosing disposal technologies for different heavy metals and be helpful to improve the application and development of cement rotary kiln co-processing hazardous wastes.

  8. Arthroscopic burring of exposed cement following curettage and cavity filling cementation for chondroblastoma of the proximal tibia.

    Science.gov (United States)

    Park, Jong-Hoon; Chae, In-Jung; Han, Seung-Beom; Lee, Dae-Hee

    2015-03-01

    Chondroblastoma of the proximal tibia is difficult to treat because of its epiphyseal predilection. This condition can be treated by curettage, which results in immediate restoration of stability and a reduced recurrence rate, followed by cement filling of the bone defect. Nevertheless, contact with cement can damage articular cartilage, potentially leading to severe knee osteoarthritis. Most previous reports regarding this complication described patients with giant cell tumors of the proximal tibia. We present here a patient who underwent arthroscopic treatment for cement exposure caused by articular cartilage loss of the tibial plateau, which occurred after initial curettage and cementation for chondroblastoma of the proximal tibia. To our knowledge, this is the first report on arthroscopic treatment of this condition.

  9. Arthroscopic burring of exposed cement following curettage and cavity filling cementation for chondroblastoma of the proximal tibia.

    Science.gov (United States)

    Park, Jong-Hoon; Chae, In-Jung; Han, Seung-Beom; Lee, Dae-Hee

    2015-03-01

    Chondroblastoma of the proximal tibia is difficult to treat because of its epiphyseal predilection. This condition can be treated by curettage, which results in immediate restoration of stability and a reduced recurrence rate, followed by cement filling of the bone defect. Nevertheless, contact with cement can damage articular cartilage, potentially leading to severe knee osteoarthritis. Most previous reports regarding this complication described patients with giant cell tumors of the proximal tibia. We present here a patient who underwent arthroscopic treatment for cement exposure caused by articular cartilage loss of the tibial plateau, which occurred after initial curettage and cementation for chondroblastoma of the proximal tibia. To our knowledge, this is the first report on arthroscopic treatment of this condition. PMID:25750896

  10. Heavy metal accumulation in soils and grains, and health risks associated with use of treated municipal wastewater in subsurface drip irrigation

    Science.gov (United States)

    Asgari, Kamran; Najafi, Payam; Cornelis, Wim M.

    2014-05-01

    Constant use of treated wastewater for irrigation over long periods may cause buildup of heavy metals up to toxic levels for plants, animals, and entails environmental hazards in different aspects. However, application of treated wastewater on agricultural land might be an effective and sustainable strategy in arid and semi-arid countries where fresh water resources are under great pressure, as long as potential harmful effects on the environment including soil, plants, and fresh water resources, and health risks to humans are minimized. The aim of this study was to assess the effect of using a deep emitter installation on lowering the potential heavy metal accumulation in soils and grains, and health risk under drip irrigation with treated municipal wastewater. A field experiment was conducted according to a split block design with two treatments (fresh and wastewater) and three sub treatments (0, 15 and 30 cm depth of emitters) in four replicates on a sandy loam soil, in Esfahan, Iran. The annual rainfall is about 123 mm, mean annual ETo is 1457 mm, and the elevation is 1590 m a.s.l.. A two-crop rotation of wheat [Triticum spp.] and corn [Zea mays]) was established on each plot with wheat growing from February to June and corn from July to September. Soil samples were collected before planting (initial value) and after harvesting (final value) for each crop in each year. Edible grain samples of corn and wheat were also collected. Elemental concentrations (Cu, Zn, Cd, Pb, Cr, Ni) in soil and grains were determined using an atomic absorption spectrophotometer. The concentrations of heavy metals in the wastewater-irrigated soils were not significantly different (P>0.05) compared with the freshwater-irrigated soils. The results showed no significant difference (P>0.05) of soil heavy metal content between different depths of emitters. A pollution load index PLI showed that there was not substantial buildup of heavy metals in the wastewater-irrigated soils compared to

  11. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  12. Fracture Resistance of Teeth Restored with Various Post Designs and Cemented with Different Cements: An In-vitro Study

    OpenAIRE

    Gaikwad, Ajay; Pal, Kapil Singh; Ranganath, L M; Jain, Jayesh Kumar; Patil, Prashanth; Babar, Geetika

    2015-01-01

    Background: Studies have been carried out on endodontically treated teeth restored with and without ferrule, and influence of the cementing medium, to evaluate their effect on fracture resistance. This study was conducted on 28 freshly extracted maxillary central incisors. Specimens were restored with two types of post designs, and cemented with two different luting agents, and tested for fracture resistance. Materials and Methods: A total of 28 freshly extracted maxillary central incisors we...

  13. Genetic and phenotypic diversity of 2,4-dichlorophenoxyacetic acid (2,4-D)-degrading bacteria isolated from 2,4-D-treated field soils.

    OpenAIRE

    Ka, J O; Holben, W E; Tiedje, J M

    1994-01-01

    Forty-seven numerically dominant 2,4-dichlorophenoxyacetic acid (2,4-D)-degrading bacteria were isolated at different times from 1989 through 1992 from eight agricultural plots (3.6 by 9.1 m) which were either not treated with 2,4-D or treated with 2,4-D at three different concentrations. Isolates were obtained from the most dilute positive most-probable-number tubes inoculated with soil samples from the different plots on seven sampling dates over the 3-year period. The isolates were compare...

  14. Survival and growth of Alfalfa (Medicago sativa l.) inoculated with an am fungus (Glomus intraradices) in contaminated soils treated with two different remediation technologies (bio-pile and thermal desorption)

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAHs) represent a group of persistent and toxic soil pollutants that are of major public concern due to their mutagenic and carcinogenic property. Phyto-remediation is the use of plants and their associated microorganisms for remediation of polluted soils. Phyto-remediation could be used in conjunction with other remediation technologies to reduce the contamination to safe levels and maintain or restore soil physico-chemical and biological properties. Most plant species form mycorrhizas with symbiotic fungi. It was shown that AM fungi enhance survival and plant growth in PAH contaminated soils. Mycorrhizal fungi also enhance the biotransformation or biodegradation of PAH, although the effect differed between soils. A rhizosphere and myco-rhizosphere gradient of PAH concentrations was observed, with decreased PAH concentration with decreased distance to roots. Different microbial communities were found in the rhizosphere of AM and non-mycorrhizal plants in comparison to bulk soil, suggesting that AM could affect PAH degradation by changing microbial communities. We investigated the effect of mycorrhizal fungi and nutrients on the ability of alfalfa to grow on soil contaminated with PAHs before and after two remediation treatments. We used soil from an industrial site (Homecourt, North East part of France) highly contaminated with PAH (2000 mg kg-1), which has been partially treated by two different remediation technologies (bio-pile and thermal desorption). The bio-pile treatment consisted of piling the contaminated soil with stimulation of aerobic microbial activity by aeration and addition of nutrient solution, and reduced PAH concentration to around 300 mg kg-1. With the thermal desorption treatment the soil was heated to around 500 deg. C so that PAH vaporized and were separated from the soil. The residual PAH concentration in soil was 40 mg kg-1. Treated and non-treated contaminated soil was planted with alfalfa (Medicago

  15. PART II. HYDRATED CEMENTS

    Directory of Open Access Journals (Sweden)

    Milan Drabik

    2014-09-01

    Full Text Available Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions - ΔH, of technological materials based on two types of Portland cements. The values of thermoanalytical events and also ΔH of probes of technological compositions, if related with the data of a choice of minerals of calcium-silicate-sulfate-aluminate hydrates, served as a valued input for the assessment of phases present and phase changes due to the topical hydraulic processes. The results indicate mainly the effects of "standard humidity" or "wet storage" of the entire hydration/hydraulic treatment, but also the presence of cement residues alongside calcium-silicate-sulfate-aluminate hydrates (during the tested period of treatment. "A diluting" effect of unhydrated cement residues upon the values of decomposition enthalpies in the studied multiphase system is postulated and discussed

  16. CHEMICALLY BONDED CEMENTS FROM BOILER ASH AND SLUDGE WASTES. PHASE II REPORT, SEPT.1998-JULY 1999.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.YAGER,K.A.BLANKENHORN,D.(KEYSPAN R AND D INITIATIVE)

    1999-08-01

    Based upon the previous Phase I research program aimed at looking for ways of recycling the KeySpan-generated wastes, such as waste water treatment sludge (WWTS) and bottom ash (BA), into the potentially useful cementitious materials called chemically bonded cement (CBC) materials, the emphasis of this Phase II program done at Brookhaven National Laboratory, in a period of September 1998 through July 1999, was directed towards the two major subjects: One was to assess the technical feasibility of WWTS-based CBC material for use as Pb-exchange adsorbent (PEA) which remediates Pb-contaminated soils in the field; and the other was related to the establishment of the optimum-packaging storage system of dry BA-based CBC components that make it a promising matrix material for the steam-cured concrete products containing sand and coarse aggregate. To achieve the goal of the first subject, a small-scale field demonstration test was carried out. Using the PEA material consisting of 30 wt% WWTS, 13 wt% Type I cement and 57 wt% water, the PES slurry was prepared using a rotary shear concrete mixer, and then poured on the Pb-contaminated soil. The PEA-to-soil ratio by weight was a factor of 2.0. The placed PEA slurry was blended with soil using hand mixing tools such as claws and shovels. The wettability of soils with the PEA was very good, thereby facilitating the soil-PEA mix procedures. A very promising result was obtained from this field test; in fact, the mount of Pb leached out from the 25-day-aged PEA-treated soil specimen was only 0.74 mg/l, meeting the requirement for EPA safe regulation of < 5 mg/l. In contrast, a large amount (26.4 mg/l) of Pb was detected from the untreated soil of the same age. Thus, this finding demonstrated that the WWTS-based CBC has a potential for use as PEA material. Regarding the second subject, the dry-packed storage system consisting of 68.7 wt% BA, 13.0 wt% calcium aluminate cement (CAC), 13.0 wt% Type I portland cement and 5.3 wt

  17. Lower leaf gas-exchange and higher photorespiration of treated wastewater irrigated Citrus trees is modulated by soil type and climate.

    Science.gov (United States)

    Paudel, Indira; Shaviv, Avi; Bernstein, Nirit; Heuer, Bruria; Shapira, Or; Lukyanov, Victor; Bar-Tal, Asher; Rotbart, Nativ; Ephrath, Jhonathan; Cohen, Shabtai

    2016-04-01

    Water quality, soil and climate can interact to limit photosynthesis and to increase photooxidative damage in sensitive plants. This research compared diffusive and non-diffusive limitations to photosynthesis as well as photorespiration of leaves of grapefruit trees in heavy clay and sandy soils having a previous history of treated wastewater (TWW) irrigation for >10 years, with different water qualities [fresh water (FW) vs TWW and sodium amended treated wastewater (TWW + Na)] in two arid climates (summer vs winter) and in orchard and lysimeter experiments. TWW irrigation increased salts (Na(+) and Cl(-) ), membrane leakage, proline and soluble sugar content, and decreased osmotic potentials in leaves of all experiments. Reduced leaf growth and higher stomatal and non-stomatal (i.e. mesophyll) limitations were found in summer and on clay soil for TWW and TWW + Na treatments in comparison to winter, sandy soil and FW irrigation, respectively. Stomatal closure, lower chlorophyll content and altered Rubisco activity are probable causes of higher limitations. On the other hand, non-photochemical quenching, an alternative energy dissipation pathway, was only influenced by water quality, independent of soil type and season. Furthermore, light and CO2 response curves were investigated for other possible causes of higher non-stomatal limitation. A higher proportion of non-cyclic electrons were directed to the O2 dependent pathway, and a higher proportion of electrons were diverted to photorespiration in summer than in winter. In conclusion, both diffusive and non-diffusive limitations contribute to the lower photosynthetic performance of leaves following TWW irrigation, and the response depends on soil type and environmental factors. PMID:26497166

  18. Reducing cement's CO2 footprint

    Science.gov (United States)

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  19. Cement og politik

    DEFF Research Database (Denmark)

    Lund, Joachim

    2012-01-01

    as well as in the public sphere. Most of the extensive job creating measures he carried out as a minister for public works necessarily involved the use of great amounts of cement – the primary produce of F.L. Smidth & Co. Gunnar Larsen thus became an easy target for Communist propaganda, picturing him...... of the Soviet Union (including an F.L. Smidth & Co. cement plant in former Estonia). He spent the last 15 months of the occupation in Sweden and was arrested after having returned to Copenhagen in May, 1945. Although a Copenhagen city court prison sentence for economic collaboration was reversed, he had...

  20. Technology Roadmaps: Cement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    To support its roadmap work focusing on key technologies for emissions reductions, the International Energy Agency (IEA) also investigated one particular industry: cement. Cement production includes technologies that are both specific to this industry and those that are shared with other industries (e.g., grinding, fuel preparation, combustion, crushing, transport). An industry specific roadmap provides an effective mechanism to bring together several technology options. It outlines the potential for technological advancement for emissions reductions in one industry, as well as potential cross-industry collaboration.

  1. Assessment of sulfide production risk in soil during the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification process.

    Science.gov (United States)

    Ghorbel, L; Coudert, L; Gilbert, Y; Mercier, G; Blais, J F

    2016-10-01

    This study aimed to determine the potential of sulfide generation during infiltration through soil of domestic wastewater treated by a sulfur-utilizing denitrification process. Three types of soil with different permeability rates (K s = 0.028, 0.0013, and 0.00015 cm/s) were investigated to evaluate the potential risk of sulfur generation during the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification system. These soils were thoroughly characterized and tested to assess their capacity to be used as drainages for wastewaters. Experiments were conducted under two operating modes (saturated and unsaturated). Sulfate, sulfide, and chemical oxygen demand (COD) levels were determined over a period of 100 days. Despite the high concentration of sulfates (200 mg/L) under anaerobic conditions (ORP = -297 mV), no significant amount of sulfide was generated in the aqueous (process used to treat the domestic wastewater allowed the reduction of the concentration of biochemical oxygen demand (BOD5) below 5 mg/L, of DOC below 7 mg/L, and of COD below 100 mg/L.

  2. Leaching tests of cemented organic radioactive waste

    International Nuclear Information System (INIS)

    The use of radioisotopes in research, medical and industrial activities generates organic liquid radioactive wastes. At Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) are produced organic liquid wastes from different sources, one of these are the solvent extraction activities, whose the waste volume is the largest one. Therefore a research was carried out to treat them. Several techniques to treat organic liquid radioactive wastes have been evaluated, among them incineration, oxidation processes, alkaline hydrolysis, distillation, absorption and cementation. Laboratory experiments were accomplished to establish the most adequate process in order to obtain qualified products for storage and disposal. Absorption followed by cementation was the procedure used in this study, i.e. absorbent substances were added to the organic liquid wastes before mixing with the cement. Initially were defined the absorbers, and evaluated the formulation in relation to the compressive strength of its products. Bentonite from different suppliers (B and G) and vermiculite in two granulometries (M - medium and F - small) were tested. In order to assess the product quality the specimens were submitted to the leaching test according the Standard ISO 6961 and its results were evaluated. Then they were compared with the values established by Standard CNEN NN 6.09 Acceptance criteria for waste products to be disposed, to verify if they meet the requirements for safely storage and disposal. Through this study the best formulations to treat the organic wastes were established. (author)

  3. Cementing a wellbore using cementing material encapsulated in a shell

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  4. The mechanical effect of the existing cement mantle on the in-cement femoral revision.

    LENUS (Irish Health Repository)

    Keeling, Parnell

    2012-08-01

    Cement-in-cement revision hip arthroplasty is an increasingly popular technique to replace a loose femoral stem which retains much of the original cement mantle. However, some concern exists regarding the retention of the existing fatigued and aged cement in such cement-in-cement revisions. This study investigates whether leaving an existing fatigued and aged cement mantle degrades the mechanical performance of a cement-in-cement revision construct.

  5. Salinity control in a clay soil beneath an orchard irrigated with treated waste water in the presence of a high water table: A numerical study

    Science.gov (United States)

    Russo, David; Laufer, Asher; Bardhan, Gopali; Levy, Guy J.

    2015-12-01

    A citrus orchard planted on a structured, clay soil associated with a high water table, irrigated by drip irrigation system using treated waste water (TWW) and local well water (LWW) was considered here. The scope of the present study was to analyze transport of mixed-ion, interacting salts in a combined vadose zone-groundwater flow system focusing on the following issues: (i) long-term effects of irrigation with TWW on the response of the flow system, identifying the main factors (e.g., soil salinity, soil sodicity) that control these effects, and (ii) salinity control aiming at improving both crop productivity and groundwater quality. To pursue this two-fold goal, 3-D numerical simulations of field-scale flow and transport were performed for an extended period of time, considering realistic features of the soil, water table, crop, weather and irrigation, and the coupling between the flow and the transport through the dependence of the soil hydraulic functions, K(ψ) and θ(ψ), on soil solution concentration C, and sodium adsorption ratio, SAR. Results of the analyses suggest that in the case studied, the long-term effect of irrigation with TWW on the response of the flow system is attributed to the enhanced salinity of the TWW, and not to the increase in soil sodicity. The latter findings are attributed to: (i) the negative effect of soil salinity on water uptake, and the tradeoff between water uptake and drainage flux, and, concurrently, solute discharge below the root zone; and, (ii) the tradeoff between the effects of C and SAR on K(ψ) and θ(ψ). Furthermore, it was demonstrated that a data-driven protocol for soil salinity control, based on alternating irrigation water quality between TWW and desalinized water, guided by the soil solution salinity at the centroid of the soil volume active in water uptake, may lead to a substantial increase in crop yield, and to a substantial decrease in the salinity load in the groundwater.

  6. Microbiological indicators for assessing ecosystem soil quality and changes in it at degraded sites treated with compost

    Science.gov (United States)

    Ancona, Valeria; Barra Caracciolo, Anna; Grenni, Paola; Di Lenola, Martina; Calabrese, Angelantonio; Campanale, Claudia; Felice Uricchio, Vito

    2014-05-01

    Soil quality is defined as the capacity of a soil to function as a vital system, within natural or managed ecosystem boundaries, sustain plant and animal health and productivity, maintain or enhance air and water environment quality and support human health and habitation. Soil organisms are extremely diverse and contribute to a wide range of ecosystem services that are essential to the sustainable functioning of natural and managed ecosystems. In particular, microbial communities provide several ecosystem services, which ensure soil quality and fertility. In fact, they adapt promptly to environmental changes by varying their activity and by increasing the reproduction of populations that have favourable skills. The structure (e.g. cell abundance) and functioning (e.g. viability and activity) of natural microbial communities and changes in them under different environmental conditions can be considered useful indicators of soil quality state. In this work we studied the quality state of three different soils, located in Taranto Province (Southern Italy), affected by land degradation processes, such as organic matter depletion, desertification and contamination (PCB and metals). Moreover, compost, produced from selected organic waste, was added to the soils studied in order to improve their quality state. Soil samples were collected before and after compost addition and both microbial and chemical analyses were performed in order to evaluate the soil quality state at each site at different times. For this purpose, the microbiological indicators evaluated were bacterial abundance (DAPI counts), cell viability (Live/Dead method), dehydrogenase activity (DHA) and soil respiration. At the same time, the main physico-chemical soil characteristics (organic carbon, available phosphorous, total nitrogen, carbonate and water content, texture and pH) were also measured. Moreover, in the contaminated soil samples PCB and inorganic (e.g. Pb, Se, Sn, Zn) contaminants were

  7. Características físicas e mecânicas de misturas de solo, cimento e cinzas de bagaço de cana-de-açúcar Physical and mechanical characteristics of soil-cement-bagasse ash mixtures

    Directory of Open Access Journals (Sweden)

    Martha Del C. Mesa Valenciano

    2004-12-01

    Full Text Available Este trabalho teve por finalidade analisar algumas características de misturas de solo, cimento e cinzas de bagaço de cana-de-açúcar para sua possível utilização na fabricação de materiais alternativos de construção. Para tal, amostras de cinzas de bagaço de cana-de-açúcar foram submetidas a um tratamento prévio que consistia de peneiramento e moagem, antes de serem incorporadas às misturas de solo e cimento. Diferentes combinações de cimento-cinzas foram estudadas, determinando-se, para cada uma delas, a consistência normal e a resistência à compressão simples, aos 7 e 28 dias. Posteriormente, corpos-de-prova moldados com tais misturas de solo-cimento-cinzas foram submetidos a ensaios de compactação, compressão simples e absorção de água. Os resultados indicaram a possibilidade de substituir até 20% do cimento Portland, na mistura, por cinzas de bagaço de cana-de-açúcar, sem prejuízo da resistência à compressão simples.This work was done with the objective of studying some physical and mechanical characteristics of the sugarcane bagasse ash added to a soil-cement mixture, in order to obtain an alternative construction material. The sugarcane bagasse ash pre-treatment included both sieving and grinding, before mixing with soil and cement. Different proportions of cement-ash were tested by determining its standard consistence and its compressive resistance at 7 and 28 days age. The various treatments were subsequently applied to the specimens molded with different soil-cement-ash mixtures which in turns were submitted to compaction, unconfined compression and water absorption laboratory tests. The results showed that it is possible to replace up to 20% of Portland cement by sugarcane bagasse ash without any damage to the mixture's compressive strength.

  8. CLAY SOIL STABILISATION USING POWDERED GLASS

    Directory of Open Access Journals (Sweden)

    J. OLUFOWOBI

    2014-10-01

    Full Text Available This paper assesses the stabilizing effect of powdered glass on clay soil. Broken waste glass was collected and ground into powder form suitable for addition to the clay soil in varying proportions namely 1%, 2%, 5%, 10% and 15% along with 15% cement (base by weight of the soil sample throughout. Consequently, the moisture content, specific gravity, particle size distribution and Atterberg limits tests were carried out to classify the soil using the ASSHTO classification system. Based on the results, the soil sample obtained corresponded to Group A-6 soils identified as ‘fair to poor’ soil type in terms of use as drainage and subgrade material. This justified stabilisation of the soil. Thereafter, compaction, California bearing ratio (CBR and direct shear tests were carried out on the soil with and without the addition of the powdered glass. The results showed improvement in the maximum dry density values on addition of the powdered glass and with corresponding gradual increase up to 5% glass powder content after which it started to decrease at 10% and 15% powdered glass content. The highest CBR values of 14.90% and 112.91% were obtained at 5% glass powder content and 5mm penetration for both the unsoaked and soaked treated samples respectively. The maximum cohesion and angle of internal friction values of 17.0 and 15.0 respectively were obtained at 10% glass powder content.

  9. The survey of cement dermatitis among construction industry workers

    Directory of Open Access Journals (Sweden)

    Faride Sadeghian

    2007-01-01

    Full Text Available Introduction: Cement has long been known as a cause of both irritant and allergic contact dermatitis. However, there are little data relating to occupational skin diseases (OSD in the Iranian construction industry. The aim of this study is to evaluate the epidemiology of cement dermatitis among terrazzo and cement manufactory workers. Methods: This is cross-sectional descriptive study. In this study 50 cement manufact-ory workers in Shahroud and 150 terrazzo workers in Lordegan were interviewed through questionnaire. Questionnaire includes demographic characteristics and questions about present dermatitis, background eczema, daily work hours, exposed chemical agents, using of gloves. Patients examined and patch tested by dermatologist. Data analyzed with SPSS software and c2, Mann Whitney and logistic regression statistical test. Results: The findings of the study showed that 8 workers (16% in cement factories and 52 workers (34.7% in Lordegan terrazzo enterprises had reported dermatitis at the time of review. Of which 15.5% in terrazzo workers had allergic contact dermatitis. In this study the prevalence of cement dermatitis increased with increasing age and there was significantly differences between dermatitis and background of dermatitis in terrazzo workers (P<0.05. Conclusion: Cement should be treated as hazardous materials, wearing of suitable gloves, early diagnosis and treatment of contact dermatitis and health education to workers is suggested.

  10. PURIFIED WASTE FCC CATALYST AS A CEMENT REPLACEMENT MATERIAL

    Directory of Open Access Journals (Sweden)

    Danute Vaiciukyniene

    2015-06-01

    Full Text Available Zeolites are commonly used in the fluid catalytic cracking process. Zeolite polluted with oil products and became waste after some time used. The quantity of this waste inevitably rises by expanding rapidly oil industry. The composition of these catalysts depends on the manufacturer and on the process that is going to be used. The main factors retarding hydration process of cement systems and modifying them strength are organic compounds impurities in the waste FCC catalyst. The present paper shows the results of using purified waste FCC catalyst (pFCC from Lithuania oil refinery, as Portland cement replacement material. For this purpose, the purification of waste FCC catalyst (FCC samples was treated with hydrogen peroxide. Hydrogen peroxide (H2O2 is one of the most powerful oxidizers known. By acting of waste with H2O2 it can eliminate the aforementioned waste deficiency, and the obtained product becomes one of the most promising ingredients, in new advanced building materials. Hardened cement paste samples with FCC or pFCC were formed. It was observed that the pFCC blended cements developed higher strength, after 28 days, compared to the samples with FCC or reference samples. Typical content of Portland cement substituting does not exceed 30 % of mass of Portland cement in samples. Reducing the consumption of Portland cement with utilizing waste materials is preferred for reasons of environmental protection.

  11. Dssimilatory Fe(Ⅲ) reduction characteristics of paddy soil extract cultures treated with glucose or fatty acids

    Institute of Scientific and Technical Information of China (English)

    HE Jiangzhou; QU Dong

    2008-01-01

    Dissimilatory Fe(Ⅲ) reduction is a universal process with irreplaceable biological and environmental importance in anoxic environments. Our knowledge about Fe(Ⅲ) reduction predominantly comes from pure cultures of dissimilatory Fe(Ⅲ) reducing bacteria (DFRB). The objective of this study was to compare the effects of glucose and a selection of short organic acids (citrate, succinate, pyruvate, propionate, acetate, and formate) on Fe(Ⅲ) reduction via the anaerobic culture of three paddy soil solutions with Fe(OH)3 as the sole electron acceptor. The results showed significant differences in Fe(Ⅲ) reduction among the three paddy soil solutions and suhstrate types. Bacteria from the Sichuan paddy soil responded quickly to substrate supply and showed higher Fe(Ⅲ) reducing activity than the other two soil types. Bacteria in the Jiangxi paddy soil culture solution could not use propionate as a source of electrons for Fe(Ⅲ) reduction. Similarly, bacteria in the Jilin paddy soil culture could not use succinate effectively. Pyruvate was readily used by cultures from all three paddy soil solutions, thus indicating that there were some similarities in substrate utilization by bacteria for Fe(Ⅲ) reduction. The use of glucose and citrate as substrate for dissimilatory Fe(Ⅲ) reduction indicates important ecological implications for this type of anoxic respiration.

  12. Experimental Study and Application on Cold -recycled Base with Cement -stabilized Sandy Soil%水泥稳定砂类土冷再生基层试验研究及应用

    Institute of Scientific and Technical Information of China (English)

    刘明辉; 平栓玲; 殷爱国

    2015-01-01

    sandy soil mixture was respectively 12.1% which shows that intensity and stability of cement -stabilized recycled mixture is better,and can meet the requirement on pavement base.(2)Engineering evaluation projects is established in detail.It mainly includes present situation,structural bearing capacity and the performance of old mixture,etc.(3)Through engineering practice,it points out the method of equipment matching on cold in -place recycling units and adding method of cement and water,and integrative operation method of milling -planing and compacting in cold in -place recycling technology is proposed.(4)Detection results of cold -recycled base show that various indexes of base can meet pavement operating requirements,and regeneration effect is good,which is provided for references to the design and construction of similar cold regenerative base.

  13. Produktie van cement

    NARCIS (Netherlands)

    Smit JRK; Coenen PWHG; Matthijsen AJCM; LAE; TAUW

    1995-01-01

    This document on cement production has been published within the SPIN project. In this project information has been collected on industrial plants or industrial processes to afford support to governmental policy on emission reduction. This document contains information on the processes, emission sou

  14. Osteotransductive bone cements.

    Science.gov (United States)

    Driessens, F C; Planell, J A; Boltong, M G; Khairoun, I; Ginebra, M P

    1998-01-01

    Calcium phosphate bone cements (CPBCs) are osteotransductive, i.e. after implantation in bone they are transformed into new bone tissue. Furthermore, due to the fact that they are mouldable, their osteointegration is immediate. Their chemistry has been established previously. Some CPBCs contain amorphous calcium phosphate (ACP) and set by a sol-gel transition. The others are crystalline and can give as the reaction product dicalcium phosphate dihydrate (DCPD), calcium-deficient hydroxyapatite (CDHA), carbonated apatite (CA) or hydroxyapatite (HA). Mixed-type gypsum-DCPD cements are also described. In vivo rates of osteotransduction vary as follows: gypsum-DCPD > DCPD > CDHA approximately CA > HA. The osteotransduction of CDHA-type cements may be increased by adding dicalcium phosphate anhydrous (DCP) and/or CaCO3 to the cement powder. CPBCs can be used for healing of bone defects, bone augmentation and bone reconstruction. Incorporation of drugs like antibiotics and bone morphogenetic protein is envisaged. Load-bearing applications are allowed for CHDA-type, CA-type and HA-type CPBCs as they have a higher compressive strength than human trabecular bone (10 MPa).

  15. Effect of climatic conditions on the development of soil water repellency in soils treated with the wastewater of the olive oil production

    Science.gov (United States)

    Schaumann, Gabriele E.; Peikert, Benjamin; Tamimi, Nesreen; Steinmetz, Zacharias; Fischer, Jonas; Bibus, Daniel; Marei Sawalha, Amer; Dag, Arnon

    2014-05-01

    The disposal of untreated wastewater on soil can induce severe water repellency. The final degree of water repellency may strongly depend on the environmental conditions prevailing during and after disposal. Also unpolluted soil can develop severe water repellency upon exposure to extreme heat or draught events. The induced water repellency can be either persistent or of transient nature. However, the underlying mechanisms are not yet completely understood. The objective of this study was to investigate how climatic conditions determine the development and persistence of water repellency following wastewater disposal. Our hypothesis was that amphiphilic organic wastewater compounds physically sorb onto surfaces, which renders them hydrophobic. Depending on temperature and moisture, those compounds are degraded, chemically incorporated into SOM, or irreversibly sorbed to soil particles during the time after the first waste water-soil contact. According to our hypothesis, biological communities favor degradation and transformation of OM of waste water into SOM under moist soil conditions. This would reduce the initial hydrophobization. In contrast, drying irreversibly renders soil hydrophobic and phytotoxic due to immobilization of OMW OM in the soil. To test these hypotheses, we investigated effects of olive mil wastewater (OMW), the effluent originating from olive oil production, directly applied to soil. In Israel and Palastine, olive oil production generates large amounts of OMW within a short period of time between November and January. As sewage facilities do not accept OMW, it is often disposed onto soil, which leads to severe soil and groundwater pollution. If the above mentioned hypotheses match, pollution and hydrophobization might be minimized if the wastewater is discharged at the right time of the year. In order to test this, we conducted field (2-3 years) and laboratory (60 days) experiments in Israel (Gilat, arid climate) and in the West Bank (Bait

  16. Immobilisation of radwaste in synthetic rock: an alternative to cementation

    International Nuclear Information System (INIS)

    SOGETER is a waste conditioning process for Low Level radwaste (LLW) or Intermediate Level radwaste (ILW) like sludge, soil, ashes, evaporator concentrate, concrete rubble, asbestos, sand,... Usually such radioactive waste is solidified into a cement matrix, resulting in a factor 2 to 5 volume increase: 1 m3 of initial raw waste generates 2 to 5 m3 of solidified waste. Sogeter consists in melting the waste at high temperature, up to 2000 K, and producing a synthetic rock. The main component of the matrix is the waste itself; therefore 1 m3 of initial raw waste generates only 0.2 to 0.5 m3 of solidified waste. Compared to cementation, synthetic rock decreases the volume to be disposed of by a factor of 4 to 25. By mixing different types of waste, or using additives, the composition of the waste is adjusted, so that a fluid melt is obtained at temperatures less than 2000 K, and so that the final 200 L ingot may be cooled down within 2 days, without shattering or dis-aggregating. We tested a wide range of compositions, demonstrating that almost every type of waste may be conditioned with Sogeter. We designed the industrial facility, based on a very robust and proven heating technology, and with a proven technology for off-gas treatment. We carried industrial tests on more than 2 tons of simulated, non-radioactive, waste, producing blocks of treated matter weighing up to 250 kg. During these tests, we checked all the parameters of the process: electrical consumption, throughput, robustness.. (author)

  17. Pharmaceuticals and personal care products in untreated and treated sewage sludge: Occurrence and environmental risk in the case of application on soil - A critical review.

    Science.gov (United States)

    Verlicchi, P; Zambello, E

    2015-12-15

    This review is based on 59 papers published between 2002 and 2015, referring to about 450 treatment trains providing data regarding sludge concentrations for 169 compounds, specifically 152 pharmaceuticals and 17 personal care products, grouped into 28 different classes. The rationale of the study is to provide data to evaluate the environmental risk posed by the spreading of treated sludge in agriculture. Following discussion of the legislative scenario governing the final disposal of treated sludge in European countries and the USA, the study provides a snapshot of the occurrence of selected compounds in primary, secondary, mixed, digested, conditioned, composted and dried sludge originating in municipal wastewater treatment plants fed mainly with urban wastewater as well as in sludge-amended soil. Not only are measured values reported, but also predicted concentrations based on Kd values are reported. It emerges that in secondary sludge, the highest concentrations were found for fragrances, antiseptics and antibiotics and an attenuation in their concentrations occurs during treatment, in particular anaerobic digestion and composting. An in-depth literature survey of the (measured and predicted) Kd values for the different compounds and treated sludge are reported and an analysis of the influence of pH, redox conditions, sludge type was carried out. The data regarding measured and predicted concentrations of selected compounds in sludge-amended soil is then analyzed. Finally an environmental risk assessment posed by their occurrence in soil in the case of land application of sludge is examined, and the results obtained by different authors are compared. The most critical compounds found in the sludge-amended soil are estradiol, ciprofloxacin, ofloxacin, tetracycline, caffeine, triclosan and triclocarban. The study concludes with a focus on the main issues that should be further investigated in order to refine the environmental risk assessment. PMID:26327643

  18. NOx from cement production - reduction by primary measures

    DEFF Research Database (Denmark)

    Jensen, Lars Skaarup

    1999-01-01

    This thesis comprises an investigation of the mechanisms involved in forming and reducing NOx in kiln systems for cement production. Particularly the mechanisms forming and reducing NOx in calciners are dealt with in detail, as altered calciner design and operation are most applicable...... to controlling NOx emission by primary measures. The main focus has been on elucidating NOx formation and reduction mechanisms involving reactions of char, and on determining their relative importance in calciners.The first three chapters give an introduction to cement production, combustion and NOx. In modern...... cement production processes cement is typically produced by thermally treating a mixture of limestone and clay minerals in kiln systems consisting of a rotary kiln and a calciner. Clinker burning at a temperature of about 1450 °C takes place in the internally fired rotary kiln and calcination, which...

  19. 夯实水泥土桩复合地基动力特性和时程响应影响因素分析%EFFECTS ON DYNAMIC CHARACTERlSTICS AND RESPONSE OF RAMMED SOIL-CEMENT PILE COMPOSITE FOUNDATION

    Institute of Scientific and Technical Information of China (English)

    王维玉; 赵拓; 丁继辉

    2011-01-01

    采用爆破地震动模拟天然地震动的方式对足比尺夯实水泥土桩复合地基进行现场动力试验研究.在空载时对天然地基和夯实水泥土桩复合地基的动力特性和时程响应进行了分析:对单桩和群桩复合地基分别在脉动和爆破作用下的动力特性和时程响应进行了分析.研究了爆破作用下,单桩和群桩复合地基峰值加速度、最大水平位移的变化规律;夯实水泥土桩在不同荷载条件下主频的变化规律;为探讨动力荷载作用下水泥土桩复合地基的承载和变形特性提供了研究基础.%Dynamic property experiments of full scale rammed soil-cement pile composite foundation are conducted by means of simulating natural earthquake through blast earthquake. With no load applied, the dynamic characteristics and time-history responses of natural foundation and rammed soil-cement pile composite foundation are analyzed firstly. Then the dynamic characteristics and time-history responses of single pile and group-piles rammed soil-cement pile composite foundation are analyzed under static load and explosions respectively. The horizontal displacement and the peak acceleration of single-pile and group-piles composite foundation under blast earthquake action are studied, as well as the variation frequencies under different load conditions. This research provides references for the later study of bearing capacity and deformation characteristics of rammed soil-cement pile under dynamic load.

  20. Cross-Contamination of Residual Emerging Contaminants and Antibiotic Resistant Bacteria in Lettuce Crops and Soil Irrigated with Wastewater Treated by Sunlight/H2O2.

    Science.gov (United States)

    Ferro, Giovanna; Polo-López, María I; Martínez-Piernas, Ana B; Fernández-Ibáñez, Pilar; Agüera, Ana; Rizzo, Luigi

    2015-09-15

    The sunlight/H2O2 process has recently been considered as a sustainable alternative option compared to other solar driven advanced oxidation processes (AOPs) in advanced treatment of municipal wastewater (WW) to be reused for crop irrigation. Accordingly, in this study sunlight/H2O2 was used as disinfection/oxidation treatment for urban WW treatment plant effluent in a compound parabolic collector photoreactor to assess subsequent cross-contamination of lettuce and soil by contaminants of emerging concern (CECs) (determined by QuEChERS extraction and LC-QqLIT-MS/MS analysis) and antibiotic resistant (AR) bacteria after irrigation with treated WW. Three CECs (carbamazepine (CBZ), flumequine (FLU), and thiabendazole (TBZ) at 100 μg L(-1)) and two AR bacterial strains (E. coli and E. faecalis, at 10(5) CFU mL(-1)) were spiked in real WW. A detection limit (DL) of 2 CFU mL(-1) was reached after 120 min of solar exposure for AR E. coli, while AR E. faecalis was more resistant to the disinfection process (240 min to reach DL). CBZ and TBZ were poorly removed after 90 min (12% and 50%, respectively) compared to FLU (94%). Lettuce was irrigated with treated WW for 5 weeks. CBZ and TBZ were accumulated in soil up to 472 ng g(-1) and 256 ng g(-1) and up-taken by lettuce up to 109 and 18 ng g(-1), respectively, when 90 min treated WW was used for irrigation; whereas no bacteria contamination was observed when the bacterial density in treated WW was below the DL. A proper treatment time (>90 min) should be guaranteed in order to avoid the transfer of pathogens from disinfected WW to irrigated crops and soil.

  1. 非饱和花岗岩残积土粒间联结作用与脆弹塑性胶结损伤模型研究%Research on soil particle joint function and brittle-elastoplastic cement damage model of unsaturated granite residual soil

    Institute of Scientific and Technical Information of China (English)

    汤连生; 桑海涛; 宋晶; 刘锋涛; 颜波; 张鹏程

    2013-01-01

    Unsaturated granite residual soil is mainly ferruginous cement, its strength decreases sharply in water, structural significant, showing brittle-elastoplastic damage characteristics, whose soil particle joint function is the core problem of structure and brittle-elastoplastic damage. The unsaturated soil particle joint function is discussed;it is divided into contact and non-contact joints, and these two kinds of joints are expressed as suction effects in soil particle intergranular interactions, that is the suction between grains composed of variable structure suction and wet suction. For unsaturated granite residual soil, particle joint function should be paid more attention. Unsaturated granite residual soil’s contact joint is dominated by ferruginous cementation and all levels of granularity composition mixtures as sand, clay and so on; they cause the suction between grains changing greatly in water or disturbance, resulting in the properties of the brittleness in the mechanics of unsaturated granite residual soil. Then through theoretical derivation, by referencing coordination number, the Smith formula, and the Fisher formula in mineralogy, crystal powder mechanics and engineering, quantitative calculation formula of variable structure suction and the soil accumulation mode, dry density, void ratio, water/saturation are given;and the rationality of the calculation formula is verified by tests. Then we research and realize that free iron oxide cement is the fundamental point of granite residual soil’s property of brittle-elastoplasticity, so a masonry model is used;and then void ratio and structure parameter are applied to construct the brittle damage process function;a theory model which can reflect the damage of unsaturated granite residual soil elastoplasticity is established. Through the comparison of calculation and experiment results. The results show that the model established above can well reflect the unique stress-strain relationship of

  2. Freeze-Thaw Performance and Moisture-Induced Damage Resistance of Base Course Stabilized with Slow Setting Bitumen Emulsion-Portland Cement Additives

    Directory of Open Access Journals (Sweden)

    Mojtaba Shojaei Baghini

    2015-01-01

    Full Text Available Freeze-thaw (FT cycles and moisture susceptibility are important factors influencing the geotechnical characteristics of soil-aggregates. Given the lack of published information on the behavior of cement-bitumen emulsion-treated base (CBETB under environmental conditions, especially freezing and thawing, this study investigated the effects of these additives on the CBETB performance. The primary goal was to evaluate the resistance of CBETB to moisture damage by performing FT, Marshall conditioning, and AASHTO T-283 tests and to evaluate the long-term stripping susceptibility of CBETB while also predicting the liquid antistripping additives to assess the mixture’s durability and workability. Specimens were stabilized with Portland cement (0%–6%, bitumen emulsion (0%–5%, and Portland cement-bitumen emulsion mixtures and cured for 7 days, and their short- and long-term performances were studied. Evaluation results of both the Marshall stability ratio and the tensile strength ratio show that the additions of additives increase the resistance of the mixtures to moisture damage. Results of durability tests performed for determining the resistance of compacted specimens to repeated FT cycles indicate that the specimen with the 4% cement-3% bitumen emulsion mixture significantly improves water absorption, volume changes, and weight losses. This indicates the effectiveness of this additive as a road base stabilizer with excellent engineering properties for cold regions.

  3. Utilization from Cement Kiln Dust in Removal of Acid Dyes

    Directory of Open Access Journals (Sweden)

    Mohamed E.S.I. Saraya

    2012-01-01

    Full Text Available Problem statement: The growth of industries and day to day changes in human activities has resulted in an increase in the volume and complexity of wastewater to the environment. Textile industry is one of the most water consumers industries of Egypt, thus discharges large amounts of wastewater effluents during processing, especially, in the coloring and washing steps. Cement kiln dust is a solid waste in cement manufacturing. Approximately 2.5-3.0 (6-9% million tons of cement kiln dust is produced annually in Egypt and that cause significant environmental problems. Approach: This study aims to investigate removal of some acid dyes from aqueous solution using cement kiln dust and monitoring the dye in colored cement kiln dust. Solution with 0.4 g L-1 concentration was treated with cement kiln dust until the color of dye disappears. The colored cement kiln residue was separate by filtration and dried. The concentration of dye was measured before and after treatment by UV-Vis spectroscopy as well as after washing of colored residue. Also, the colored residue was investigated with, XRD, IR and DSC techniques as well as the loss on ignition at 450°C. Results: The results found that the cement kiln dust has the power to remove all existing acid dyes and the residue has the same color of dye. When colored residue was washed with water, there was no back diffusion of dye in to water. This may be mainly due to chemical reaction that took place between cement kiln dust and dye. Thus analysis such as IR, XRD and DSC are in agreement with these results. Conclusion: CKD is efficient in the processes of dye removal from aqueous solutions. The interaction between acid dye and CKD is fast (just minutes. So, we suggest using spent CKD for dye removal of waste water.

  4. Shear behaviour and stiffness of naturally cemented sands

    OpenAIRE

    Cuccovillo, T.

    1995-01-01

    The behaviour of natural soils is highly influenced by structural features arising from their geological history and was recognised to lie outside current frameworks which account only for the stress-volume state of the soil. The objective of the research was to compare the shear behaviour and stiffness of two naturally cemented sands: a calcarenite with relatively low densities, weak particles and strong bonding and a silica sandstone with high densities, strong particles and weak bonding. C...

  5. Heavy metal accumulation in soils and grains, and health risks associated with use of treated municipal wastewater in subsurface drip irrigation.

    Science.gov (United States)

    Asgari, Kamran; Cornelis, Wim M

    2015-07-01

    Constant use of treated wastewater (TWW) for irrigation over prolonged periods may cause buildup of heavy metals up to toxic levels for plants and animals, and entails environmental hazards in different aspects. However, application of TWW on agricultural land might be an effective and sustainable strategy in arid and semi-arid countries where fresh water resources are under great pressure, as long as potential harmful effects on the environment including soil, plants, and fresh water resources, and health risks to humans are minimized. The aim of this study was to assess the effect of deep emitters on limiting potential heavy metal accumulation in soils and grains, and health risk under drip irrigation with treated municipal wastewater. A field experiment was conducted according to a split block design with two treatments (fresh and wastewater) and three sub-treatments (0, 15, and 30 cm depth of emitters) in four replicates on a sandy loam Calcic Argigypsids, in Esfahan, Iran. The annual rainfall is about 123 mm, mean annual ETo is 1457 mm, and the elevation is 1590 m above sea level. A two-crop rotation of wheat (Triticum spp.) and corn (Zea mays) was established on each plot with wheat growing from February to June and corn from July to September. Soil samples were collected before planting and after harvesting for each crop in each year. Edible grain samples of corn and wheat were collected at harvest. Elemental concentrations (Cu, Zn, Cd, Pb, Cr, Ni) in soil and grains were determined using an atomic absorption spectrophotometer. Results showed that the concentrations of heavy metals in the wastewater-irrigated soils were not significantly different (P > 0.05) compared with the freshwater-irrigated soils. No significant difference (P > 0.05) in heavy metal content in soil between different depths of emitters was found. A pollution load index (PLI) showed that there was no substantial buildup of heavy metals in the wastewater-irrigated soils

  6. The effect of cement creep and cement fatigue damage on the micromechanics of the cement-bone interface.

    NARCIS (Netherlands)

    Waanders, D.; Janssen, D.; Mann, K.A.; Verdonschot, N.J.J.

    2010-01-01

    The cement-bone interface provides fixation for the cement mantle within the bone. The cement-bone interface is affected by fatigue loading in terms of fatigue damage or microcracks and creep, both mostly in the cement. This study investigates how fatigue damage and cement creep separately affect th

  7. Speciation and bioaccessibility of lead and cadmium in soil treated with metal-enriched Indian mustard leaves

    Institute of Scientific and Technical Information of China (English)

    Yanshan Cui; Jin Fu; Xiaochen Chen

    2011-01-01

    Indian mustard (Brassica juncea (L.) Czern.) has shown good potential for the phytoremediation of soil contaminated with heavy metals. However, there is little information about the speciation and bioaccessibility of heavy metals in soil during the decomposition of metal-rich Indian mustard leaves. Incubation experiments (1-, 3-, and 6-month) were carried out in Beijing and Hunan soil with metal-rich Indian mustard leaves addition (1% and 3%) and the effects of mustard leaves addition on the speciation and bioaccessibility of heavy metals were studied. The results showed that the addition of mustard leaves led to significant increases in pH and DOC in the Hunan soil. Both 1% and 3% of mustard leaf amendment caused the percentage of the exchangeable (F1), precipitated with carbonates (F2), bound to Fe/Mn oxides (F3) and bound to organic matter (F4) fractions of Pb and Cd to increase dramatically, while the percentage of the residual fraction (F5) of Cd and Pb significantly dropped in both Beijing and Hunan soils. Mustard leaf addition caused the bioaccessibility of Pb to decrease in the gastric phase, whereas the values increased in the small intestinal phase. The Cd bioaccessibility increased with mustard leaf addition in both the gastric and small intestinal phases. In conclusion, the metal-enriched mustard leaves addition induces Pb and Cd concentrations and their mobility increasing in the Beijing and Hunan soils. Therefore, heavy metal risk in metal-enriched plant leaves should be considered in phytoremediation system in which heavy metal might be brought back to soil and changed over time.

  8. Isotropic Compression Behaviour of Fibre Reinforced Cemented Sand

    Directory of Open Access Journals (Sweden)

    Salahuddin

    2013-07-01

    Full Text Available Fibre-reinforced cemented sands have many applications in improving the response of soils. In this paper, an experimental investigation for the analysis of fiber-reinforced cemented sand in the framework of isotropic compression is presented. The experimental investigations were carried out using a high pressure triaxial apparatus having the capacity of 64 MPa of confining pressure. Tests have been conducted on Portaway sand specimens reinforced with randomly oriented discrete polypropylene fibers with different percentages of fiber and cement contents. Results are presented in the form of e-logp` curves as well as SEM (Scanning Electron Microscopy micrographs. The effects of the addition of fibre in sand and cemented sand for different initial void ratios were investigated. The results demonstrate that the influence of fibre is not significant in both cemented and uncemented sand during the isotropic compression stage. Moreover, from the SEM micrographs it could be seen that there is breakage of sand particles and cement bonds. The fiber threads were seen pinched and found rarely broken in the specimen exhumed after isotropic compression.

  9. An injectable calcium phosphate cement for the local delivery of paclitaxel to bone

    NARCIS (Netherlands)

    Lopez-Heredia, M.A.; Kamphuis, G.J.; Thune, P.C.; Oner, F.C.; Jansen, J.A.; Walboomers, X.F.

    2011-01-01

    Bone metastases are usually treated by surgical removal, fixation and chemotherapeutic treatment. Bone cement is used to fill the resection voids. The aim of this study was to develop a local drug delivery system using a calcium phosphate cement (CPC) as carrier for chemotherapeutic agents. CPC cons

  10. Incorporação de casca de arroz e de braquiária e seus efeitos nas propriedades físicas e mecânicas de tijolos de solo-cimento Incorporation of rice and brachiaria husk and their effects on physical and mechanical properties of soil-cement bricks

    Directory of Open Access Journals (Sweden)

    Régis de C. Ferreira

    2008-03-01

    Full Text Available A forma indiscriminada de extração dos recursos naturais e a poluição gerada pelos resíduos promovem impactos sobre o meio ambiente e é motivo de grande preocupação. Visando a oferecer alternativas de destinação de resíduos agrícolas, o presente trabalho estudou composições da mistura de solo-cimento-resíduo agrícola, tendo como objetivo principal determinar os teores máximos de resíduos a serem incorporados sem o comprometimento de suas características mecânicas. Foram utilizados dois tipos de resíduos vegetais (cascas de arroz e de braquiária e utilizou-se o cimento Portland CP II-F-32 para a composição dos tratamentos. Nas combinações, os teores de cimento e resíduo variaram desde 100% de cimento e 0% de resíduo, até 60% de cimento e 40% de resíduo. Os tijolos foram prensados com o auxílio de máquina de fabricação de tijolos e submetidos aos ensaios de compressão simples e absorção de água. Os melhores resultados, em termos de resistência à compressão simples e de absorção de água, foram obtidos pelos tratamentos com substituição de 10% de resíduos vegetais em relação ao teor de cimento. De forma geral, os resultados sugerem a possibilidade do uso desses resíduos no teor de 10%, sem o comprometimento das propriedades mecânicas relacionadas à resistência e à absorção de água dos tijolos de solo-cimento.The aim of this research was to study the effect of vegetable wastes addition on physical and mechanical properties of soil-cement bricks. It was used two types of wastes (rice and Brachiaria brizantha rusk.The Portland cement content used on the soil stabilization was of 10%. The combinations of cement and vegetable wastes contents varied from 100% of cement content and 0% of wastes content to 60% of cement content and 40% of waste content. The bricks were submitted to the compression tests and to the water absorption test. The best results, in terms of compression strength and water

  11. Arsenic Accumulation by Pteris vittata L. in Two Chemically Variant Soils Treated with Arsenical Pesticides - Greenhouse Study

    Science.gov (United States)

    Therapong, C.; Datta, R.; Sarkar, D.; Pachanoor, D.

    2006-05-01

    Arsenic (As) is one of the most toxic elements present in the environment. Over the years, arsenic has found its way to the environment due to its extensive use in agriculture and in industrial practices as pesticides, fertilizers, wood preservatives, smelter wastes and coal combustion ash, all of which are of great environmental concern. Arsenic contamination affects biological activities because it is a carcinogen and a mutagen, which has detrimental effects on the immune system of animals. Remediation of arsenic-contaminated soils has become a major environmental issue in the recent years. Several physical and chemical treatment methods, such as soil washing, co-precipitation, and excavation, have used to remediate As, but all of these methods are rather expensive and can disturb soil physiology and ecology. Phytoremediation, a plant based technology for the removal of toxic contaminants from soil and water is an attractive approach. Of late, this technology has received a high degree of attention from the scientific community because it is environment-friendly and also because of its tremendous cost efficiency compared to the conventional methods. Chinese Brake Fern (Pteris vittata L.) is a known arsenic hyperaccumulator that is being used extensively at present to remove As from soils. However, the degree of efficiency of this plant in accumulating As is likely to be a function of the soil properties. The objective of the reported study was to investigate arsenic uptake by Chinese Brake Fern in As-contaminated soils from the Immokalee (acid sand with minimal As-retention potential) and Millhopper series (sandy loam with high Fe/Al content, hence, high As-retention potential). A greenhouse experiment was designed to evaluate the effects on As uptake by Chinese Brake Fern at two pesticide application rates: 225 mg/kg and 500 mg/kg As in two chemical forms, namely sodium arsenate (AsV) and dimethylarsinic acid (DMA). Each treatment was replicated three times in

  12. POZZOLAN AND CEMENTS WITH POZZOLAN

    Directory of Open Access Journals (Sweden)

    Hasan KAPLAN

    1995-02-01

    Full Text Available Cement, one of the basic material of construction engineering, has an important place in view of strength and cost of structures. Cement consumption is increasing parallel to development of building construction sector. For cement producers, minimal cost is desired by using new and economical material sources. On the other hand, the controllers and contractors need cheaper, safer and higher strength materials. From this respect cement industry tends to use cement with pozzolan. In Türkiye, cement with pozzolan is produced by adding the pozzolan, which has a large reservoir in the country, in cement in sertain amount. However this type of cement is consumed in the construction sector, sortage of scientific investigation and speculative news on the subject.are worried the users and producers. In this paper, prior to an experimental study on the cements having pozzolan additive, historical development of pozzolan, reservoir of Turkiye, and comparison with portland cement is carried out. Advantages and disadvantages of pozzolan are also discussed in some points.

  13. Comparison of soil amendments to decrease high strength in SE USA Coastal Plain soils using fuzzy decision-making analyses

    Science.gov (United States)

    Cemented subsurface layers restrict root growth in many southeastern USA Coastal Plain soils. Though cementation is usually reduced by tillage, soil amendments can offer a more permanent solution if they develop aggregation. To increase aggregation, we amended 450 g of a Norfolk soil blend of 90% E ...

  14. Mineral resource of the month: hydraulic cement

    Science.gov (United States)

    van Oss, Hendrik G.

    2012-01-01

    Hydraulic cements are the binders in concrete and most mortars and stuccos. Concrete, particularly the reinforced variety, is the most versatile of all construction materials, and most of the hydraulic cement produced worldwide is portland cement or similar cements that have portland cement as a basis, such as blended cements and masonry cements. Cement typically makes up less than 15 percent of the concrete mix; most of the rest is aggregates. Not counting the weight of reinforcing media, 1 ton of cement will typically yield about 8 tons of concrete.

  15. Preliminary systems design study assessment report. [Evaluation of using specific technologies, system concepts for treating the buried waste and surrounding contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Mayberry, J.L.; Feizollahi, F.; Del Signore, J.C.

    1992-01-01

    The System Design Study (SDS), part of the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examined techniques available for the remediation of hazardous and transuranic waste stored at the Radioactive Waste Management Complex's Subsurface Disposal Area at the INEL. Using specific technologies, system concepts for treating the buried waste and the surrounding contaminated soil were evaluated. Evaluation included implementability, effectiveness, and cost. The SDS resulted in the development of technology requirements including demonstration, testing, and evaluation activities needed for implementing each. This volume contains the descriptions and other relevant information of the four subsystems required for most of the ex situ processing systems. This volume covers the metal decontamination and sizing subsystem, soils processing subsystem, low-level waste subsystem, and retrieval subsystem.

  16. Attenuation of Metal Bioavailability in Acidic Multi-Metal Contaminated Soil Treated with Fly Ash and Steel Slag

    Institute of Scientific and Technical Information of China (English)

    QIU Hao; GU Hai-Hong; HE Er-Kai; WANG Shi-Zhong; QIU Rong-Liang

    2012-01-01

    A pot experiment was conducted with multi-metal (Pb,Cd,Cu,and Zn) contaminated acidic soil to investigate changes in available metal burden resulting from the application of industrial wastes (fly ash and steel slag).The efficiency of amendmentsinduced metal stabilization was evaluated by diffusive gradients in thin films (DGT),sequential extraction,and plant uptake.The stability of remediation was assessed by an acidification test and by chemical equilibrium modeling.Addition of fly ash (20 g kg-1) and steel slag (3 g kg-1 ) resulted in similar increase in soil pH.Both amendments significantly decreased the concentrations of metals measured with DGT (CDGT) and the metal uptake by Oryza sativa L.Significant correlations were found between CDGT and the concentration of a combination of metal fractions (exchangeable,bound to carbonates,and bound to Fe/Mn oxides),unraveling the labile species that participate in the flux of metal resupply.The capability of metal resupply,as reflected by the R (ratio of CDGT to pore water metal concentration) values,significantly decreased in the amended soils.The CDGT correlated well with the plant uptake,suggesting that DGT is a good indicator for bioavailability.Acidification raised the extractable metal concentration in amended soil but the concentration did not return to the pre-amendment level.Equilibrium modeling indicated that the soil amendments induced the precipitation of several Fe,Al and Ca minerals,which may play a positive role in metal stabilization.Chemical stabilization with alkaline amendments could be an effective and stable soil remediation strategy for attenuating metal bioavailability and reducing plant metal uptake.

  17. US cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Nisbet, M.A.

    1997-12-31

    This paper describes the cement and concrete industry, and provides data on energy use and carbon dioxide emissions. The potential impact of an energy tax on the industry is briefly assessed. Opportunities identified for reducing carbon dioxide emissions include improved energy efficiency, alternative fuels, and alternative materials. The key factor in determining CO{sub 2} emissions is the level of domestic production. The projected improvement in energy efficiency and the relatively slow growth in domestic shipments indicate that CO{sub 2} emissions in 2000 should be about 5% above the 1990 target. However, due to the cyclical nature of cement demand, emissions will probably be above target levels during peak demand and below target levels during demand troughs. 7 figs., 2 tabs.

  18. Performance of Cement Containing Laterite as Supplementary Cementing Material

    Directory of Open Access Journals (Sweden)

    Abbas Bukhari, Z. S.

    2013-03-01

    Full Text Available The utilization of different industrial waste, by-products or other materials such as ground granulated blast furnace slag, silica fume, fly ash, limestone, and kiln dust, etc. as supplemen- tary cementing materials has received considerable attention in recent years. A study has been conducted to look into the performance of laterite as Supplementary Cementing Materials (SCM. The study focuses on compressive strength performance of blended cement containing different percentage of laterite. The cement is replaced accordingly with percentage of 2 %, 5 %, 7 % and 10 % by weight. In addition, the effect of use of three chemically different laterites have been studied on physical performance of cement as in setting time, Le-Chatlier expansion, loss on ignition, insoluble residue, free lime and specifically compressive strength of cement cubes tested at the age of 3, 7, and 28 days. The results show that the strength of cement blended with laterite as SCM is enhanced. Key words: Portland cement, supplementary cementing materials (SCM, laterite, compressive strength KUI – 6/2013 Received January 4, 2012 Accepted February 11, 2013

  19. Comparison of Potassium Dissolving Rate for Organic-inorganic Complex Materials Cement and Coating Fertilizer in Different Soils%不同土壤淋洗方式下有机-无机复合材料胶结包膜肥料钾素溶出速率比较

    Institute of Scientific and Technical Information of China (English)

    肖强; 王甲辰; 左强; 张琳; 邹国元; 赵同科; 刘宝存

    2011-01-01

    应用由水基成膜法研制的4种有机-无机复合材料胶结包膜肥料(B2、PS、F2、F2F)进行土柱淋洗试验,研究其在不同土壤类型条件下的钾素溶出规律.结果表明:4种胶结包膜肥料在48d内钾素累积溶出率为44.02%(红壤) >34.59%(褐土)>25.92%(黑土).同一种胶结包膜肥料在红壤、褐土和黑土中的钾素瞬时溶出率峰值出现时间一致(以B2为例);钾素溶出峰值之前,瞬时溶出率在2~13 d内为红壤>褐土>黑土,钾素峰值溶出率为10.39%(红壤)>7.09%(褐土)>5.99%(黑土),而峰值过后,三土壤间瞬时溶出率差异不显著(P>0.05).说明包膜肥料本身释放钾素的速率受不同质地的土壤影响较小,但其淋出量受土壤影响较大.%Four kinds of organic-inorganic complex materials cement and coating fertilizers prepared by a coating method using water as the solvent were carried out to study on potassium dissolved rate in different soils with columns leaching way. The results showed that potassium accumulated dissolution rate in 48d were 44.02% (red soil)> 34.59% (drab soil)> 25.92% (black soil). As for B2, the appearing peak time of potassium instant dissolution rate was same for same kind of cement and coating fertilizer in different soils. Before the peak time, the potassium instantaneous dissolving rates between 2-13 days arranged as red soil > drab soil > black soil. The summit instantaneous potassium dissolving rates arranged as 10.39% (red soil) > 7.09% (drab soil) > 5.99% (black soil), respectively. However, after the peak time, no significant difference was found between these three soils' potassium dissolving rates (P < 0.05). The effects of texture on potassium dissolving from cement and coating fertilizer were insignificant, but the impact of leaching amount was great.

  20. Modelling and simulation of acrylic bone cement injection and curing within the framework of vertebroplasty

    CERN Document Server

    Landgraf, Ralf; Kolmeder, Sebastian; Lion, Alexander; Lebsack, Helena; Kober, Cornelia

    2013-01-01

    The minimal invasive procedure of vertebroplasty is a surgical technique to treat compression fractures of vertebral bodies. During the treatment liquid bone cement gets injected into the affected vertebral body and therein cures to a solid. In order to investigate the treatment and the impact of injected bone cement on the vertebra, an integrated modelling and simulation framework has been developed. The framework includes (i) the generation of computer models based on microCT images of human cancellous bone, (ii) CFD simulations of bone cement injection into the trabecular structure of a vertebral body as well as (iii) non-linear FEM simulations of the bone cement curing. Thereby, microstructural models of trabecular bone structures are employed. Furthermore, a detailed description of the material behaviour of acrylic bone cements is provided. More precisely, a non-linear fluid flow model is chosen for the representation of the bone cement behaviour during injection and a non-linear viscoelastic material mo...

  1. Preliminary Systems Design Study assessment report. [Evaluation of using specific technologies, system concepts for treating the buried waste and the surrounding contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Mayberry, J.L.; Feizollahi, F.; Del Signore, J.C.

    1991-11-01

    The System Design Study (SDS), part of the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examined techniques available for the remediation of hazardous and transuranic waste stored at the Radioactive Waste Management Complex's Subsurface Disposal Area at the INEL. Using specific technologies, system concepts for treating the buried waste and the surrounding contaminated soil were evaluated. Evaluation included implementability, effectiveness, and cost. The SDS resulted in the development of technology requirements including demonstration, testing, and evaluation activities needed for implementing each concept.

  2. Temporal variability of soil microbial communities after application of dicyandiamide-treated swine slurry and mineral fertilizers

    NARCIS (Netherlands)

    Suleiman, A.K.A.; Gonzatto, Rogerio; Aita, Celso; Lupatini, M.; Jacques, Rodrigo; Kuramae, E.E.; Antoniolli, Zaida; Roesch, Luiz

    2016-01-01

    In modern agriculture, mineral and organic fertilization account for most of the global anthropogenic N2O emissions. A strategy to prevent or to reduce emissions of greenhouse gases such as N2O is the use of nitrification inhibitors, which temporarily inhibit the microbial conversion of soil ammoniu

  3. [Haemotoxicity of dental luting cements].

    Science.gov (United States)

    Anders, A; Welker, D

    1989-06-01

    A glass ionomer luting cement (AquaCem) shows a relatively low haemolytic activity in comparison with two zinc phosphate cements. Especially the initial irritation by this cement is smaller. Although it is possible that AquaCem particularly, in unfavourable cases, may damage the pulpa dentin system; this is due to the slowly decrease of the haemolytic activity with increasing of the probes. We found that Adhesor showed in dependence of the batches a varying quality. PMID:2626769

  4. Cement penetration after patella venting.

    Science.gov (United States)

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement. PMID:19010682

  5. Bone-Cement: The new medical quick fix

    Directory of Open Access Journals (Sweden)

    Dinesh Bhatia

    2010-01-01

    Full Text Available Bone Cement is being widely used in vertebroplasty, a minimally invasive surgical procedure to treat spinal frac-tures and collapsed vertebrae. It is being labeled as a concrete success in medical field. It is being used to treat fractures due to osteoporosis, menopause, steroids, hyperthyroidism and chronic obstructive pulmonary diseases. In this technique a needle with bone cement (PMMA, polymethylmethacrylate is injected into the collapsed verte-bra after administering local anesthesia to patient. It solidifies within few minutes and provides support to damaged bone resulting in relief to the patient. It also prevents the movement between different parts of the broken bone. Hence it requires a short hospital stay for the patient and the procedure can be performed with much ease and at significant lower costs. Patient can resume normal activity within a day or so. Bone cement is now being referred to as the quick medical fix material for early repair of fractures.

  6. Hypoplastic model for simulation of compressibility characteristics of cement-admixed Bangkok soft clay at high water content

    Science.gov (United States)

    Chattonjai, Piyachat

    2016-06-01

    The developed hypoplastic model for simulation of compressibility characteristics of cement-admixed Bangkok soft clay at high water content was proposed in this paper. By using unique equation, the model is able to predict the relationship between void ratio and vertical effective stress of different water and cement content of soil cement. For practically convenient utilization and understanding, the parameters of Q1 which represented to initial cement bonding of soil (the initial value of structure tensor at time = 0) and C2 which effected to the model stiffness on isotropic consolidation direction, at 45° for loading and 225° for unloading of stress response envelope, were proposed as the function of cement and water content by comparing with dry weight of soil. By numerical integration that satisfied one-dimensional settlement, the simulation results were directly compared with fifteen experimental results to verify the accuracy of the proposed model.

  7. Removal of Ni(II) and Cu(II) ions using native and acid treated Ni-hyperaccumulator plant Alyssum discolor from Turkish serpentine soil.

    Science.gov (United States)

    Bayramoglu, Gulay; Arica, M Yakup; Adiguzel, Nezaket

    2012-09-01

    Alyssum discolor biomass was collected from serpentine soil and was used for removal of metal ions. The plant species grown on serpentine soils are known to be rich with metals ions and thus have more capability for accumulating heavy metals. Native and acid-treated biomass of A. discolor (A. discolor) were utilized for the removal of Ni(II) and Cu(II) ions from aqueous solutions. The effects of contact time, initial concentration, and pH on the biosorption of Ni(II) and Cu(II) ions were investigated. Biosorption equilibrium was established in about 60 min. The surface properties of the biomass preparations were varied with pH, and the maximum amounts of Ni(II) and Cu(II) ions on both A. discolor biomass preparations were adsorbed at pH 5.0. The maximum biosorption capacities of the native, and acid-treated biomass preparations for Ni(II) were 13.1 and 34.7 mgg(-1) and for Cu(II) 6.15 and 17.8 mgg(-1) dry biomass, respectively. The biosorption of Ni(II) and Cu(II) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. When the heavy metal ions were in competition, the amounts of biosorbed metal ions on the acid treated plant biomass were found to be 0.542 mmolg(-1) for Ni(II) and 0.162 mmolg(-1) for Cu(II), the A. discolor biomass was significantly selective for Ni(II) ions. The information gained from these studies was expected to indicate whether the native, and acid-treated forms can have the potential to be used for the removal and recovery of Ni(II) ions from wastewaters. PMID:22608134

  8. Respiratory Health among Cement Workers in Ethiopia

    OpenAIRE

    Zeleke, Zeyede K.

    2011-01-01

    Background: Little is known on dust exposure and respiratory health among cement cleaners. There are only a few follow-up studies on respiratory health among cement factory workers and also studies on acute effects of cement dust exposure are limited in numbers. Objective: This study aimed at assessing cement dust exposure and adverse respiratory health effects among Ethiopian cement production workers, with particular focus on cement cleaners. Method: The first paper was...

  9. Thermal Shock-resistant Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  10. CCA transport in soil from treated-timber posts: pattern dynamics from the local to regional scale

    OpenAIRE

    Clothier, B.E.; Green, S. R.; Vogeler, I.; M. M. Greven; Agnew, R.; C. W. van den Dijssel; Neal, S; Robinson, B H; Davidson, P.

    2006-01-01

    Winegrape growing in many parts of the world, including Marlborough, New Zealand, uses treated-timber posts to act as supports for the grapevine's canopy. At a density of 580 posts per hectare, the H4-process treated supports result in an areal loading of CCA of: Copper (12 kg-Cu ha−1), Chromium (21 kg-Cr ha−1) and Arsenic (17 kg-As ha−1). Arsenic is the most mobile and toxic of the CCA-tre...

  11. Soil stabilization using oil shale solid wastes: Laboratory evaluation of engineering properties

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.P.

    1991-01-01

    Oil shale solid wastes were evaluated for possible use as soil stabilizers. A laboratory study was conducted and consisted of the following tests on compacted samples of soil treated with water and spent oil shale: unconfined compressive strength, moisture-density relationships, wet-dry and freeze-thaw durability, and resilient modulus. Significant increases in strength, durability, and resilient modulus were obtained by treating a silty sand with combusted western oil shale. Moderate increases in strength, durability, and resilient modulus were obtained by treating a highly plastic clay with combusted western oil shale. Solid waste from eastern shale can be used for soil stabilization if limestone is added during combustion. Without limestone, eastern oil shale waste exhibits little or no cementation. The testing methods, results, and recommendations for mix design of spent shale-stabilized pavement subgrades are presented. 11 refs., 3 figs., 10 tabs.

  12. The Effects of Eggshell Ash on Strength Properties of Cement-stabilized Lateritic

    Directory of Open Access Journals (Sweden)

    Okonkwo U. N

    2012-04-01

    Full Text Available Eggshell ash obtained by incinerating Fowls’ eggshells to ash has been established to be a good accelerator for cement-bound materials and this would be useful for road construction work at the peak of rainy seasons for reducing setting time of stabilized road pavements. However this should be achieved not at the expense of other vital properties of the stabilized matrix. This is part of the effort in adding value to agricultural materials which probably cause disposal problems. Thus this study aimed at determining the effect of eggshell ash on the strength properties of cement-stabilized lateritic soil. The lateritic soil was classified to be A-6(2 in AASHTO rating system and reddish-brown clayey sand (SC in the Unified Classification System. Constant cement contents of 6% and 8% were added to the lateritic soil with variations in eggshell ash content of 0% to 10% at 2% intervals. All proportions of cement and eggshell ash contents were measured in percentages by weight of the dry soil. The Compaction test, California Bearing Ratio test, Unconfined Compressive Strength test and Durability test were carried out on the soil-cement eggshell ash mixtures. The increase in eggshell ash content increased the Optimum Moisture Content but reduced the Maximum Dry Density of the soil-cement eggshell ash mixtures. Also the increase in eggshell ash content considerably increased the strength properties of the soil-cement eggshell ash mixtures up to 35% in the average but fell short of the strength requirements except the durability requirement was satisfied.

  13. Effect of Chemical Admixtures on the Engineering Properties of Tropical Peat Soils

    Directory of Open Access Journals (Sweden)

    Bujang B.K. Huat

    2005-01-01

    Full Text Available This research describes a study on the effect of chemical (cement and lime admixtures on the index and engineering properties (compaction and unconfined strength of tropical peat soils. The ordinary Portland cement and hydrated lime were used. The amounts cement and lime added to the peat soil sample, as a percentage of the dry soil mass was in the range of 5-15% and 5-25%, respectively. The results of the study show that the addition of the chemical admixture, cement and lime, can improve the engineering properties of tropical peat soils. The soil liquid limit is found to decrease with an increase in the cement and lime content. The soil maximum dry density is found to increase while the optimum water content is found to decrease with an increase in the cement and lime content. The unconfined compressive strength of the soil is found to increase significantly with increase in cement and lime content, especially after a long curing period. However it is also found that higher organic content of the soil negate the positive effect of the cement and lime in altering (improving the mechanical properties of the soil. When comparing the performance of the cement and lime as a chemical admixture for the tropical peat soil, the ordinary Portland cement appears to perform better than the hydrated lime.

  14. Structural and functional response of the soil bacterial community to application of manure from difloxacin-treated pigs

    NARCIS (Netherlands)

    Jechalke, S.; Focks, A.; Rosendahl, I.; Groeneweg, J.; Siemens, J.; Heuer, H.; Smalla, K.

    2014-01-01

    Difloxacin (DIF) belongs to the class of fluoroquinolone antibiotics that have been intensively used for the treatment of bacterial infections in veterinary and human medicine. The aim of this field study was to compare the effect of manure from DIF-treated pigs and untreated pigs on the bacterial c

  15. Compatibility of Pretreated Coir Fibres (Cocos nucifera L.) with Portland Cement to Produce Mineral Composites

    OpenAIRE

    Ferraz, Joana M.; Cláudio H. S. Del Menezzi; Mario R. Souza; Okino, Esmeralda Y. A.; Martins, Sabrina A.

    2012-01-01

    The objectives of the present work were to evaluate the chemical compatibility between coir (Cocos nucifera L.) and cement and to study treatment methods to improve this compatibility. In the inhibition test, cement hydration temperature evolution was measured in the absence and presence of untreated and treated coir fibres (cold water, hot water and NaOH), besides the addition of 4% of CaCl2. The chemical characterization of untreated and treated coir fibres was done by determining the conte...

  16. An Ice Block: A Novel Technique of Successful Prevention of Cement Leakage Using an Ice Ball

    International Nuclear Information System (INIS)

    We report three cases of painful bone metastases with extraosseous invasion treated with cementoplasty and cryoablation. Due to significant cortical loss in all cases, the ice ball was used simultaneously during cementoplasty to deter potential cement leakage. This was achieved by direct application of the ice ball against the cortical surface, resulting in adequate consolidation and successful containment of the cement within the treated bones. To the authors’ knowledge, this is the first report to describe such a combined technique

  17. An Ice Block: A Novel Technique of Successful Prevention of Cement Leakage Using an Ice Ball

    Energy Technology Data Exchange (ETDEWEB)

    Uri, Ishaq Fahmi, E-mail: uri.isaac@gmail.com [The Royal National Orthopaedic Hospital (United Kingdom); Garnon, Julien, E-mail: juliengarnon@gmail.com; Tsoumakidou, Georgia, E-mail: georgia.tsoumakidou@chru-strasbourg.fr; Gangi, Afshin, E-mail: gangi@unistra.fr [Hôpital Universitaire de Strasbourg, Service d’Imagerie Interventionnelle (France)

    2015-04-15

    We report three cases of painful bone metastases with extraosseous invasion treated with cementoplasty and cryoablation. Due to significant cortical loss in all cases, the ice ball was used simultaneously during cementoplasty to deter potential cement leakage. This was achieved by direct application of the ice ball against the cortical surface, resulting in adequate consolidation and successful containment of the cement within the treated bones. To the authors’ knowledge, this is the first report to describe such a combined technique.

  18. Prediction of zeolite-cement-sand unconfined compressive strength using polynomial neural network

    Science.gov (United States)

    MolaAbasi, H.; Shooshpasha, I.

    2016-04-01

    The improvement of local soils with cement and zeolite can provide great benefits, including strengthening slopes in slope stability problems, stabilizing problematic soils and preventing soil liquefaction. Recently, dosage methodologies are being developed for improved soils based on a rational criterion as it exists in concrete technology. There are numerous earlier studies showing the possibility of relating Unconfined Compressive Strength (UCS) and Cemented sand (CS) parameters (voids/cement ratio) as a power function fits. Taking into account the fact that the existing equations are incapable of estimating UCS for zeolite cemented sand mixture (ZCS) well, artificial intelligence methods are used for forecasting them. Polynomial-type neural network is applied to estimate the UCS from more simply determined index properties such as zeolite and cement content, porosity as well as curing time. In order to assess the merits of the proposed approach, a total number of 216 unconfined compressive tests have been done. A comparison is carried out between the experimentally measured UCS with the predictions in order to evaluate the performance of the current method. The results demonstrate that generalized polynomial-type neural network has a great ability for prediction of the UCS. At the end sensitivity analysis of the polynomial model is applied to study the influence of input parameters on model output. The sensitivity analysis reveals that cement and zeolite content have significant influence on predicting UCS.

  19. Concepts for ecotoxicological analysis of contaminated and treated soils; Konzepte zur oekotoxikologischen Bewertung kontaminierter und sanierter Boeden

    Energy Technology Data Exchange (ETDEWEB)

    Dott, W.; Eisentraeger, A.; Maxam, G.; Scheen, H. [RWTH, Aachen (Germany). Inst. fuer Hygiene und Umweltmedizin

    1999-07-01

    In contrast to chemical analyses, biological test methods provide a picture of the combined effects of all pollutants as sum parameters, as well as the bioavailable pollutant fractions. Pollutants fixed in the soil outside the range of roots are not taken up by plants and are therefore not toxicologically relevant, but they will appear in chemical analyses. Biological methods, in combination with suitable evaluation strategies, are recommended for characterizing the potential hazards of pollutants in soils. [German] Die toxikologisch/oekotoxikologische Bewertung von Boeden wird in Zukunft neben dem chemisch-analytischen Nachweis von Schadstoffen im Boden an Bedeutung gewinnen. Waehrend mit chemisch-analytischen Methoden nur die Substanzen quantifiziert werden, nach denen gesucht wird, erfassen die biologischen Testmethoden als Summenparameter die Kombinationswirkung aller vorhandenen Substanzen. Ausserdem erfassen sie die bioverfuegbaren Schadstoffanteile. Die Schadstoffanteile, die am Boden fixiert sind, nicht im Wurzelbereich liegen und daher nicht von Pflanzen aufgenommen werden koennen, sind toxikologisch nicht relevant. Durch die chemischen Analysen werden sie bei Gesamtaufschluessen jedoch mit erfasst. Zur Charakterisierung des Gefaehrdungspotentials von Schadstoffen in Boeden koennen diese Methoden in Verbindung mit entsprechenden Bewertungsstrategien verwendet werden. (orig.)

  20. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    A K Misra; Renu Mathur

    2007-06-01

    The scope of magnesium oxychloride (MOC) cement in concrete works has been evaluated. MOC cement concrete compositions of varying strengths having good placing and finishing characteristics were prepared and investigated for their compressive and flexural strengths, -values, abrasion resistance etc. The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ratio of compressive to flexural strength varies between 6 and 8. The elastic moduli of the compositions studied are found to be 23–85 GPa and the abrasion losses between 0.11 and 0.20%. While alternate heating–cooling cycles have no adverse effect on MOC concrete, it can be made durable against freezing–thawing and the excessive exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution of the same concentration.

  1. Development of the Use of Alternative Cements for the Treatment of Intermediate Level Waste

    International Nuclear Information System (INIS)

    This paper describes initial development studies undertaken to investigate the potential use of alternative, non ordinary Portland cement (OPC) based encapsulation matrices to treat historic legacy wastes within the UK's Intermediate Level Waste (ILW) inventory. Currently these wastes are encapsulated in composite OPC cement systems based on high replacement with blast furnace slag of pulverised fuel ash. However, the high alkalinity of these cements can lead to high corrosion rates with reactive metals found in some wastes releasing hydrogen and forming expansive corrosion products. This paper therefore details preliminary results from studies on two commercial products, calcium sulfo-aluminate (CSA) and magnesium phosphate (MP) cement which react with a different hydration chemistry, and which may allow wastes containing these metals to be encapsulated with lower reactivity. The results indicate that grouts can be formulated from both cements over a range of water contents and reactant ratios that have significantly improved fluidity in comparison to typical OPC cements. All designed mixes set in 24 hours with zero bleed and the pH values in the plastic state were in the range 10-11 for CSA and 5-7 for MP cements. In addition, a marked reduction in aluminium corrosion rate has been observed in both types of cements compared to a composite OPC system. These results therefore provide encouragement that both cement types can provide a possible alternative to OPC in the immobilisation of reactive wastes, however further investigation is needed. (authors)

  2. Radioactive bone cement for the treatment of spinal metastases: a dosimetric analysis of simulated clinical scenarios

    Science.gov (United States)

    Kaneko, T. S.; Sehgal, V.; Skinner, H. B.; Al-Ghazi, M. S. A. L.; Ramsinghani, N. S.; Marquez Miranda, M.; Keyak, J. H.

    2012-07-01

    Vertebral metastases are a common manifestation of many cancers, potentially leading to vertebral collapse and neurological complications. Conventional treatment often involves percutaneous vertebroplasty/kyphoplasty followed by external beam radiation therapy. As a more convenient alternative, we have introduced radioactive bone cement, i.e. bone cement incorporating a radionuclide. In this study, we used a previously developed Monte Carlo radiation transport modeling method to evaluate dose distributions from phosphorus-32 radioactive cement in simulated clinical scenarios. Isodose curves were generally concentric about the surface of bone cement injected into cadaveric vertebrae, indicating that dose distributions are relatively predictable, thus facilitating treatment planning (cement formulation and dosimetry method are patent pending). Model results indicated that a therapeutic dose could be delivered to tumor/bone within ∼4 mm of the cement surface while maintaining a safe dose to radiosensitive tissue beyond this distance. This therapeutic range should be sufficient to treat target volumes within the vertebral body when tumor ablation or other techniques are used to create a cavity into which the radioactive cement can be injected. With further development, treating spinal metastases with radioactive bone cement may become a clinically useful and convenient alternative to the conventional two-step approach of percutaneous strength restoration followed by radiotherapy.

  3. Pulmonary cement embolism after pedicle screw vertebral stabilization

    Directory of Open Access Journals (Sweden)

    Massimo Tonolini

    2012-01-01

    Full Text Available Pulmonary arterial embolization of polymethylmethacrylate cement, most usually occurring after vertebroplasty or kyphoplasty, is very uncommon following vertebral stabilization procedures. Unenhanced CT scans viewed at lung window settings allow confident identification of cement emboli in the pulmonary circulation along with possible associate parenchymal changes, whereas hyperdense emboli may be less conspicuous on CT-angiographic studies with high-flow contrast medium injection. Although clinical manifestations are largely variable from asymptomatic cases to severe respiratory distress, most cases are treated with anticoagulation.

  4. Confidence HIGH VISCOSITY BONE CEMENT SYSTEM AND POSTURAL REDUCTION IN TREATING ACUTE SEVERE OSTEOPOROTIC VERTEBRAL COMPRESSION FRACTURES%Confidence高黏度骨水泥椎体成形系统结合体位复位治疗急性重度骨质疏松性椎体压缩骨折

    Institute of Scientific and Technical Information of China (English)

    李波; 王群波; 余雨; 杜维; 邵高海

    2011-01-01

    目的 探讨应用Confidence高黏度骨水泥椎体成形系统结合体位复位治疗急性重度骨质疏松性椎体压缩骨折(osteoporotic vertebral compression fracture,OVCF)的临床效果.方法 回顾分析2004年6月-2009年6月采用Confidence高黏度骨水泥及其椎体成形系统结合体位复何治疗34例急性重度OVCF患者的临床资料.男14例,女20例;年龄62~88岁,平均72.6岁.均为单椎体骨折.损伤节段:T114例,T1210例,L115例,L24例,L31例.骨密度测定T值均≤-2.5,提示骨质疏松.伤后至入院时间2~72 h.术前先对压缩椎体行腰椎过伸位复位7~14 d,术中采用单侧穿刺,经椎弓根入路,每个椎体注射骨水泥2~6 mL,平均3.2 mL.结果 术中3例(8.8%)椎体出现不同程度骨水泥渗漏,其中2例椎体渗漏全椎间隙,1例椎体渗漏至椎旁软组织;均无临床症状,末行处理.患者均无肺栓塞、感染和神经损伤等并发症发生.34例均获随访,随访时间12~38个月,平均18.5个月.术后31例术前疼痛症状完全缓解,3例部分缓解;未见伤椎再骨折、骨与骨水泥界面松动及相邻椎体骨折发生.术后3 d及未次随访时伤椎前中柱椎体高度、后凸Cobb角及疼痛视觉模拟评分(VAS)均较术前显著改善(P0.05).结论 Confidence高黏度骨水泥椎体成形系统具有瞬间高黏度、可注射时间长、定向可控注射等优点,降低了骨水泥渗漏风险,术前结合体何复位治疗急性重度OVCF疗效较好.%Objective To evaluate the effectiveness of Confidence high viscosity bone cement system and postural reduction in treating acute severe osteoporotic vertebral compression fracture (OVCF).Methods Between June 2004 and June 2009, 34 patients with acute severe OVCF were treated with Confidence high viscosity bone cement system and postural reduction.There were 14 males and 20 females with an average age of 72.6 years (range, 62-88 years).All patients had single thoracolumbar fracture, including 4

  5. Method Cement Post-grouting to Increase the Load Capacity for Bored Pile

    Directory of Open Access Journals (Sweden)

    Van Loc Nguyen

    2013-05-01

    Full Text Available Drilled shafts foundations are used as an indispensable solution for long span bridges in Vietnam. In order to increase the bearing capacity, aside from the increasing of the pile length and diameter, an interested way now is treatment of pile bases after concrete placement. This study is aimed at investigating the defect at the bottom of the bored pile from the sonic test. The injection of hight pressure of cement grout to the shaft and tip of the defected bored pile was conducted to increase the bearing capacity of pile. The bearing capacity of defected bored pile is calculated by the TCXD-205:1998 an finite element mothod. After post-grouting technique done, the soil investigation tests have been carried out to define the properties of treated soils. The analytic mothod, finite element method an load test also have been applied to determine the bearing capacity of treated bored pile. The results show that the post-grouting to the shaft and tip of pile can increase two times of bearing capacity of defected bored pile and about 20% compared to the normal bored pile.

  6. Postprocedural CT for perivertebral cement leakage in percutaneous vertebroplasty is not necessary - results from VERTOS II

    Energy Technology Data Exchange (ETDEWEB)

    Venmans, Alexander; Klazen, Caroline A.; Rooij, Willem Jan van; Lohle, Paul N. [St. Elisabeth Ziekenhuis Tilburg, Department of Radiology, Tilburg (Netherlands); Vries, Jolanda de [St. Elisabeth Ziekenhuis Tilburg, Department of Medical Psychology, Tilburg (Netherlands); Mali, Willem P. [University Medical Centre Utrecht, Department of Radiology, Utrecht (Netherlands)

    2011-01-15

    During percutaneous vertebroplasty (PV), perivertebral cement leakage frequently occurs. There is some concern that cement deposits may migrate towards the lungs via the veins during follow-up. We used baseline and follow-up computed tomography (CT) to assess the incidence and extend of late cement migration in a large consecutive patient cohort. VERTOS II is a prospective multicenter randomized controlled trial comparing PV with conservative therapy for osteoporotic vertebral compression fractures (OVCFs). Patients assigned to PV had baseline postprocedural CT scans of the treated vertebral bodies. After a mean follow-up of 22 months, 54 of 78 patients (69%) had follow-up CT. CT scans were analyzed and compared for perivertebral venous, discal, and soft tissue leakage. Perivertebral cement leakage occurred in 64 of 80 treated vertebrae (80%; 95% CI, 70% to 87%). All patients remained asymptomatic. Perivertebral venous leakage was present in 56 vertebrae (88%), mostly in the anterior external venous plexus (46 of 56, 82%). Discal leakage occurred in 22 of 64 vertebrae (34%) and soft tissue leakage in two of 64 (4%). Mean injected cement volume in vertebrae with leakage was higher (4.5 versus 3.7 cm{sup 3}, p = 0.04). Follow-up CT scan showed unchanged perivertebral cement leakages without late cement migration. Perivertebral cement leaks during PV for OVCFs occurred frequently in the VERTOS II trial. Cement leakage occurred more frequently with higher injected volumes. However, all patients remained asymptomatic, and late cement migration during follow-up did not occur. Standard postprocedural CT of the treated vertebral body in PV is not necessary. (orig.)

  7. Dioxins in soil treated with 2,4-D in a municipality of the State of Rio de Janeiro, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Cheble Bahia Braga, A.M.; Monteiro Rosa, J. [National School of Public Health, Oswaldo Cruz Foundation, Rio de Janeiro (Brazil); Krauss, T. [National Institute for Quality Control in Health, Oswaldo Cruz Foundation, Rio de Janeiro (Brazil)

    2004-09-15

    In Brazil, the herbicide 2,4,5-T was prohibited due to the presence of high dioxins concentrations as impurity in its formulations but the herbicide 2,4-D is widely used to control broad-leaf weeds in several plantations such as sugar cane, coffee, potato among others or prior to planting in order to prepare soil for plantation. The National Agency for Sanitary Surveillance (ANVISA), the authority in charge of the pesticides registry, also established the concentration of 0.1 ppm as maximum limit for dioxins in 2,4-D formulations. It is also a common practice to use this herbicide associated with Glyphosate to reduce or replace manual or mechanical weeding. In 2000, the Secretary of Health of Cantagalo, Municipality in the north part of Rio de Janeiro State was notified about a possible environmental contamination by the application of 2,4-D at a coffee farm named Santa Guilhermina. Spraying had occurred in an area close to a creek used as a source of drinking water of a school and as a water supply for a second district of this municipality. Special care was given to the possibility of PCDD/Fs contamination of the drinking water supply directly through 2,4-D aplication and indirectly through the transfer by run-off. Thus, it was requested scientific advice and analytical support to verify whether or not contamination had occurred. They had called for technical support only 8 days after the episode and considering the very low solubility of PCDD/Fs in water and their high tendency to adsorb on particles, it was decided to check if the soil had been contaminated by these activities and to use this database for further decision-making, as well. It was also looked up for original 2,4-D formulation in the area to verify the possible presence of PCDD/Fs but none was available.

  8. 21 CFR 888.4200 - Cement dispenser.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027)...

  9. Asymptomatic Bone Cement Pulmonary Embolism after Vertebroplasty: Case Report and Literature Review

    Directory of Open Access Journals (Sweden)

    Girolamo Geraci

    2013-01-01

    Full Text Available Introduction. Acrylic cement pulmonary embolism is a potentially serious complication following vertebroplasty. Case Report. A 70-year-old male patient was treated with percutaneous vertebroplasty for osteoporotic nontraumatic vertebral collapse of L5-S1. Asymptomatic pulmonary cement embolism was detected on routine postoperative chest radiogram and the patient was treated with enoxaparin, amoxicillin, and dexamethasone. At the followup CT scan no further migration of any cement material was reported; and the course was uneventful. Discussion. The frequency of local leakage of bone cement is relatively high (about 80–90%, moreover, the rate of cement leakage into the perivertebral veins (seen in up to 24% of vertebral bodies treated with consequent pulmonary cement embolism varies from 4.6 to 6.8% (up to 26% in radiologic studies; the risk of embolism is increased with the liquid consistency of the cement and with the treatment of some malignant lesions. Patients may remain asymptomatic and develop no known long-term sequelae. Conclusions. Our ancedotal case illustrates the need for close monitoring of patients undergoing percutaneous vertebroplasty and emphasizes the importance of prompt and correct diagnosis and treatment, even if actually there is no agreement regarding the therapeutic strategy.

  10. Cements in Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    The use of cement and concrete to immobilise radioactive waste is complicated by the wide- ranging nature of inorganic cementing agents available as well as the range of service environments in which cement is used and the different functions expected of cement. For example, Portland cement based concretes are widely used as structural materials for construction of vaults and tunnels. These constructions may experience a long pre-closure performance lifetime during which they are required to protect against collapse and ingress of water: strength and impermeability are key desirable characteristics. On the other hand, cement and concrete may be used to form backfills, ranging in permeability. Permeable formulations allow gas readily to escape, while impermeable barriers retard radionuclide transport and reduce access of ground water to the waste. A key feature of cements is that, while fresh, they pass through a fluid phase and can be formed into any shape desired or used to infiltrate other materials thereby enclosing them into a sealed matrix. Thereafter, setting and hardening is automatic and irreversible. Where concrete is used to form structural elements, it is also natural to use cement in other applications as it minimises potential for materials incompatibility. Thus cement- mainly Portland cement- has been widely used as an encapsulant for storage, transport and as a radiation shield for active wastes. Also, to form and stabilise structures such as vaults and silos. Relative to other potential matrices, cement also has a chemical immobilisation potential, reacting with and binding with many radionuclides. The chemical potential of cements is essentially sacrificial, thus limiting their performance lifetime. However performance may also be required in the civil engineering sense, where strength is important, so many factors, including a geochemical description of service conditions, may require to be assessed in order to predict performance lifetime. The

  11. Cement/slag chemistry studies

    International Nuclear Information System (INIS)

    The performance of cement-based matrices intended for radwaste immobilization is assessed. The long-term performance of the matrix is characterized by thermodynamic evaluation of experimental data. The results are presented in a general form, amenable to a range of specific formulations. The interaction of specific radwaste components with cements has been studied, using Iodine as an example. It occurs as both I- and IO3- species, but these differ sharply in sorption characteristics. The effect of ionizing radiation of the pH and Eh of cement matrices is reported. (author)

  12. Application of Cement Mortar Mixing Pile in Treatment of Soft-soil Foundation of Tianjin-Baoding Railway%水泥砂浆桩在津保铁路软土地基处理中的应用

    Institute of Scientific and Technical Information of China (English)

    甘兴旺

    2013-01-01

    Taking the engineering of the soft foundation for DK55-DK67 Section of Tianjin-Baoding Railway reinforced by cement mortar mixing pile as the example, the technological test, construction process and specifications relating to cement mortar mixing pile are described, and the construction quality inspection and control points are generalized. The on-site inspection result shows that the cement mortar mixing pile has such high strength that the bearing capacity of the soft foundation so reinforced is improved; and the effect of such reinforcement is good enough to meet the requirement of foundation treatment for 200-250 km/h PDL and line for mixed passenger and freight traffic.%以津保铁路DK55~DK67段水泥砂浆桩加固处理软基工程为例,叙述了水泥砂浆桩工艺试验、施工工艺流程及工艺参数等,总结了施工质量检测及控制要点.现场检测结果表明,水泥砂浆桩成桩强度高,加固软土地基后地基承载力提高,加固效果好,能满足200 ~ 250 km/h铁路客运专线和客货共线铁路地基加固处理要求.

  13. Tribendimidine and albendazole for treating soil-transmitted helminths, Strongyloides stercoralis and Taenia spp.: open-label randomized trial.

    Directory of Open Access Journals (Sweden)

    Peter Steinmann

    Full Text Available BACKGROUND: Tribendimidine is an anthelminthic drug with a broad spectrum of activity. In 2004 the drug was approved by Chinese authorities for human use. The efficacy of tribendimidine against soil-transmitted helminths (Ascaris lumbricoides, hookworm, and Trichuris trichiura has been established, and new laboratory investigations point to activity against cestodes and Strongyloides ratti. METHODOLOGY/PRINCIPAL FINDINGS: In an open-label randomized trial, the safety and efficacy of a single oral dose of albendazole or tribendimidine (both drugs administered at 200 mg for 5- to 14-year-old children, and 400 mg for individuals > or = 15 years against soil-transmitted helminths, Strongyloides stercoralis, and Taenia spp. were assessed in a village in Yunnan province, People's Republic of China. The analysis was on a per-protocol basis and the trial is registered with controlled-trials.com (number ISRCTN01779485. Both albendazole and tribendimidine were highly efficacious against A. lumbricoides and, moderately, against hookworm. The efficacy against T. trichiura was low. Among 57 individuals who received tribendimidine, the prevalence of S. stercoralis was reduced from 19.3% to 8.8% (observed cure rate 54.5%, p = 0.107, and that of Taenia spp. from 26.3% to 8.8% (observed cure rate 66.7%, p = 0.014. Similar prevalence reductions were noted among the 66 albendazole recipients. Taking into account "new" infections discovered at treatment evaluation, which were most likely missed pre-treatment due to the lack of sensitivity of available diagnostic approaches, the difference between the drug-specific net Taenia spp. cure rates was highly significant in favor of tribendimidine (p = 0.001. No significant adverse events of either drug were observed. CONCLUSIONS/SIGNIFICANCE: Our results suggest that single-dose oral tribendimidine can be employed in settings with extensive intestinal polyparasitism, and its efficacy against A. lumbricoides and hookworm

  14. Barium and sodium in sunflower plants cultivated in soil treated with wastes of drilling of oil well

    Directory of Open Access Journals (Sweden)

    Jésus Sampaio Junior

    2015-11-01

    Full Text Available ABSTRACTThis study aimed to evaluate the effects of the application of two types of oil drilling wastes on the development and absorption of barium (Ba and sodium (Na by sunflower plants. The waste materials were generated during the drilling of the 7-MGP-98D-BA oil well, located in the state of Bahia, Brazil. The treatments consisted of: Control – without Ba application, comprising only its natural levels in the soil; Corrected control – with fertilization and without wastes; and the Ba doses of 300, 3000 and 6000 mg kg-1, which were equivalent to the applications of 16.6, 165.9 and 331.8 Mg ha-1 of waste from the dryer, and 2.6, 25.7 and 51.3 Mg ha-1 of waste from the centrifugal. Plants cultivated using the first dose of dryer waste and the second dose of centrifugal waste showed growth and dry matter accumulation equal to those of plants under ideal conditions of cultivation (corrected control. The highest doses of dryer and centrifugal wastes affected the development of the plants. The absorption of Ba by sunflower plants was not affected by the increase in the doses. Na proved to be the most critical element present in the residues, interfering with sunflower development.

  15. Pesticide tolerant and phosphorus solubilizing Pseudomonas sp. strain SGRAJ09 isolated from pesticides treated Achillea clavennae rhizosphere soil.

    Science.gov (United States)

    Rajasankar, R; Manju Gayathry, G; Sathiavelu, A; Ramalingam, C; Saravanan, V S

    2013-05-01

    In this study, an attempt was made to identify an effective phosphate solubilizing bacteria from pesticide polluted field soil. Based on the formation of solubilization halo on Pikovskaya's agar, six isolates were selected and screened for pesticide tolerance and phosphate (P) solubilization ability through liquid assay. The results showed that only one strain (SGRAJ09) obtained from Achillea clavennae was found to tolerate maximum level of the pesticides tested and it was phylogenetically identified as Pseudomonas sp. It possessed a wide range of pesticide tolerance, ranging from 117 μg mL(-1) for alphamethrin to 2,600 μg mL(-1) for endosulfan. The available P concentrations increased with the maximum and double the maximum dose of monocrotophos and imidacloprid, respectively. On subjected to FT-IR and HPLC analysis, the presence of organic acids functional group in the culture broth and the production of gluconic acid as dominant acid aiding the P solubilization were identified. On comparison with control broth, monocrotophos and imidacloprid added culture broth showed quantitatively high organic acids production. In addition to gluconic acid production, citric and acetic acids were also observed in the pesticide amended broth. Furthermore, the Pseudomonas sp. strain SGRAJ09 possessed all the plant growth promoting traits tested. In presence of monocrotophos and imidacloprid, its plant growth promoting activities were lower than that of the pesticides unamended treatment.

  16. Structural behavior of load bearing brick walls of soil-cement with the addition of ground ceramic waste Comportamento estrutural de paredes estruturais de tijolos de solo-cimento com adição de resíduo cerâmico moído

    Directory of Open Access Journals (Sweden)

    Humberto C. Lima Júnior

    2003-12-01

    Full Text Available An experimental study of three load bearing walls is presented and discussed in this paper. The walls were of soil-cement bricks made with three different material proportions, in which two of them had part of the cement amount replaced by crushed ceramic waste. The walls were 95.20 cm high, 75.32 cm wide and 12.56 cm thick and had their bricks layered with cement paste. The walls were tested under compression and their displacements were measured with 5 dial gages. The walls had satisfactory behaviour and their strengths were suitable as required by Brazilian popular houses. The differences between the brick strength and the wall strength were less than 20%. A finite element analysis (FEA was performed and the uniformity of the compressive stress distributions in the walls was evaluated. Finally, it was observed that the partial replacement of the cement by crushed ceramic waste is possible.Neste trabalho, apresenta-se resultados do estudo experimental de três paredes estruturais, construídas com tijolos de solo-cimento. Os tijolos foram fabricados com três diferentes proporções de materiais, nas quais duas delas tiveram parte do cimento substituído por resíduo cerâmico moído. As paredes apresentavam altura de 95,20 cm, largura de 75,32 cm e espessura de 12,56 cm e tiveram seus tijolos rejuntados com pasta de cimento, que foram ensaiadas sob compressão centrada e tiveram seus deslocamentos avaliados por cinco relógios medidores de deslocamento. Observou-se comportamento estrutural satisfatório e resistências compatíveis com as requeridas pelas paredes das casas populares brasileiras. Em todos os casos, as diferenças entre as tensões máximas nas paredes e as resistências dos tijolos, foram inferiores a 20%. Para concluir o estudo, realizou-se análise por meio do método dos elementos finitos (MEF com o intuito de avaliar a uniformidade na distribuição das tensões ao longo das paredes. Finalmente, observou-se que a substitui

  17. Influence of curing conditions on durability of alkali-resistant glass fibres in cement matrix

    Indian Academy of Sciences (India)

    Arabi Nourredine

    2011-07-01

    Glass fibres in concrete material often increase the flexural strength. However, these fibres when in contact with cement are altered by alkali reactions due to the presence of portlandite. This study presents the results of investigation to show the effect of curing conditions on the durability of alkali-resistant glass fibres in cement matrix. Test results show that even alkali resistant fibres treated with zirconium oxide present the same degradation phenomenon. They also show that the nature of the cement has a large influence on the protection of the fibres: the Portland CEM II is less damaging than the CEM I. The substitutions of a part of cement by silica fume gave no substantial improvements to the mechanical strength of the glass fibre reinforced cement (GFRC). However, the observed microstructures in the samples show that the degradation is weakened with the addition of silica fumes. The analytical techniques used in this study are scanning electron microscope (SEM) and X-ray diffraction.

  18. Cementing porcelain-fused-to-metal crowns.

    Science.gov (United States)

    Vadachkoria, D

    2009-12-01

    The clinical success of fixed prosthodontic restorations can be complex and involve multifaceted procedures. Preparation design, oral hygiene/micro flora, mechanical forces, and restorative materials are only a few of the factors which contribute to overall success. One key factor to success is choosing the proper cement. Popular use of cements for PFM crowns has shifted from zinc phosphate and glass ionomer cements to resin-reinforced glass ionomer, or RRGI, cements. This change has been rapid and profound. Dental cements have always been less than ideal materials, but this is shift to the relatively new RRGI category justified. Resin-reinforced glass ionomer (RRGI) cements appear to be better than zinc phosphate and glass ionomer cements when placing porcelain-to-metal crowns. RRGI cements, such as RelyX Luting, Fuji Plus and Vitremer Luting Cement, satisfy more of the ideal characteristics of PFM cementation than any other previous cement. Expansion of all three cements has not caused any apparent problems with the cements when used with PFM or metal crowns, but these cements, however, should be avoided when cementing all-ceramic crowns. PMID:20090144

  19. Heavy Metal Desorption From Cement Hydrates Caused by Chloride Solutions

    OpenAIRE

    Hayashi, Akihiko; Ogawa, Yuko; Kawai, Kenji

    2014-01-01

    After the demolition of concrete structures, it is expected to recycle the whole of the demolished concrete. As of now, however, it is difficult to recycle the fine powders generated in the processes of demolition of concrete and manufacture of recycled aggregate because these powders may contain heavy metals exceeding the soil environmental standard, and such powders are disposed finally. It is well known that heavy metals are easily adsorbed on cement hydrates. To promote the total recyclin...

  20. Nutrient, metal and microbial loss in surface runoff following treated sludge and dairy cattle slurry application to an Irish grassland soil.

    Science.gov (United States)

    Peyton, D P; Healy, M G; Fleming, G T A; Grant, J; Wall, D; Morrison, L; Cormican, M; Fenton, O

    2016-01-15

    Treated municipal sewage sludge ("biosolids") and dairy cattle slurry (DCS) may be applied to agricultural land as an organic fertiliser. This study investigates losses of nutrients in runoff water (nitrogen (N) and phosphorus (P)), metals (copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), cadmium (Cd), chromium (Cr)), and microbial indicators of pollution (total and faecal coliforms) arising from the land application of four types of treated biosolids and DCS to field micro-plots at three time intervals (24, 48, 360 h) after application. Losses from biosolids-amended plots or DCS-amended plots followed a general trend of highest losses occurring during the first rainfall event and reduced losses in the subsequent events. However, with the exception of total and faecal coliforms and some metals (Ni, Cu), the greatest losses were from the DCS-amended plots. For example, average losses over the three rainfall events for dissolved reactive phosphorus and ammonium-nitrogen from DCS-amended plots were 5 and 11.2 mg L(-1), respectively, which were in excess of the losses from the biosolids plots. When compared with slurry treatments, for the parameters monitored biosolids generally do not pose a greater risk in terms of losses along the runoff pathway. This finding has important policy implications, as it shows that concern related to the reuse of biosolids as a soil fertiliser, mainly related to contaminant losses upon land application, may be unfounded. PMID:26410697

  1. Preliminary Systems Design Study assessment report. [Evaluation of using specific technologies, system concepts for treating the buried waste and the surrounding contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Mayberry, J.L.; Feizollahi, F.; Del Signore, J.C.

    1992-01-01

    The System Design Study (SDS), part of the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examined techniques for the remediation of hazardous and transuranic waste stored at Radioactive Waste Management Complex's Subsurface Disposal Area at the INEL. Using specific technologies, system concepts for treating the buried waste and the surrounding contaminated soil were evaluated. Evaluation included implementability, effectiveness, and cost. The SDS resulted in the development of technology requirements including demonstration, testing, and evaluation activities needed for implementing each concept. This volume contains introduction section containing a brief SDS background and lists the general assumptions and considerations used during the development of the system concepts. The introduction section is followed by sections describing two system concepts that produce a waste form in compliance with the Waste Isolation Pilot Plant (WIPP) Waste Acceptance Criteria (WAC) and transportation package (TRAMPAC) requirements. This system concept category is referred to as Waste Form 4, WIPP and TRAMPAC Acceptable.'' The following two system concepts are under this category: Sort, Treat, and Repackage System (4-BE-2); Volume Reduction and Packaging System (4-BE-4).

  2. 水泥土桩及CFG桩刚柔组合桩复合地基动力试验结果分析%The Analysis of Dynamic Test Results on Cement-soil Pile and CFG Pile Combined Composite Foundation

    Institute of Scientific and Technical Information of China (English)

    胡晓强; 赵拓

    2015-01-01

    Based on the idea of pile-type optimization,rammed soil-cement pile and CFG pile composition were grouped to rigid-flexible piles composite foundation,the dynamic test were completed using blasting simulating earthquake,two different kinds piles dynamic response in rigid-flexible piles composite foundation were studied. From the Angle of the peak acceleration,frequency and duration are analyzed in comparison,we got the conclusions. In the same under blasting vibration loading,all other conditions being equal,along with the rising of the upper load,the peak accelerations of cement-soil pile and CFG pile composite foundation were decrease,Blasting vibration duration were increase gradually,from the pile bottom to top,the maximum were located on the top of the pile.%基于优化桩型的思想,选取夯实水泥土桩及CFG桩进行优化组合,组成刚柔组合桩复合地基.用爆破的方式模拟地震提供震源,进行现场动力试验,通过研究不同载荷作用下,组合桩中夯实水泥土桩、CFG桩两种桩不同的动力反应,分别从峰值加速度、主频及持续时间的角度进行了对比研究,得到了在爆破地震荷载作用及其他条件都相同时,随着静载试验载荷量的增大,两种桩型的峰值加速度逐渐减小;两种桩型爆破地震动持续时间从桩顶到桩底逐渐增大的结论.

  3. Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

    OpenAIRE

    Adriana Eštoková; Lenka Palaščáková

    2013-01-01

    The radionuclide activities of 226Ra, 232Th and 40K and radiological parameters (radium equivalent activity, gamma and alpha indices, the absorbed gamma dose rate and external and internal hazard indices) of cements and cement composites commonly used in the Slovak Republic have been studied in this paper. The cement samples of 8 types of cements from Slovak cement plants and five types of composites made from cement type CEM I were analyzed in the experiment. The radionuclide activities in t...

  4. Assessment of the compatibility of wood and plastic with cement for their recycling in cement composites

    OpenAIRE

    Andrade, André De; Caldeira, Fernando

    2010-01-01

    The compatibility between maritime pine wood and cement, and between plastic (LDPE) and cement, was assessed for the recycling of wood and plastic in cement composites. Temperature vs. time profiles of cement setting were registered and compatibility indices were calculated. Results indicate that recycling of plastics in plastic-cement composites does not pose any questions regarding chemical compatibility. However, maritime pine hinders cement setting in some extent. So, in or...

  5. Durability of Cement Composites Reinforced with Sisal Fiber

    Science.gov (United States)

    Wei, Jianqiang

    understanding of degradation mechanisms, two approaches are proposed to mitigate the degradation of sisal fiber in the cement matrix. In order to relieve the aggressive environment of hydrated cement, cement substitution by a combination of metakaolin and nanoclay, and a combination of rice husk ash and limestone are studied. Both metakaolin and nanoclay significantly optimize the cement hydration, while the combination of these two supplementary cementitious materials validates their complementary and synergistic effect at different stages of aging. The presented approaches effectively reduce the calcium hydroxide content and the alkalinity of the pore solution, thereby mitigating the fiber degradation and improving both the initial mechanical properties and durability of the fiber-cement composites. The role of rice husk ash in cement modification is mainly as the active cementitious supplementary material. In order to improve the degradation resistance of sisal fiber itself, two novel, simple, and economical pretreatments of the fibers (thermal and sodium carbonate treatment) are investigated. Both thermal treatment and Na 2CO3 treatment effectively improve the durability of sisal fiber-reinforced concrete. The thermal treatment achieves improvement of cellulose's crystallization, which ensures the initial strength and improved durability of sisal fiber. A layer consisting of calcium carbonate sediments, which protects the internals of a fiber from the strong alkali pore solution, is formed and filled in pits and cavities on the Na2CO3 treated sisal fiber's surface.

  6. Epigeal fauna of a degraded soil treated with mineral fertilizer and compound cellulose cultivated of tree species

    Science.gov (United States)

    Giácomo, R. G.; de Arruda, O. G.; Souto Filho, S. N.; Alves, M. C.; Pereira, M. G.; Frigério, G. C.

    2012-04-01

    The aim of this study was to investigate the behavior of the epigeal fauna in a degraded soil in the recovery process after one year of cultivated with tree species. The experiment was established in February 2010 in Mato Grosso do Sul, Brazil. The experimental design was randomized blocks in split plots with five treatments and four replications. In the main plots, pure cultivation of Eucalyptus urograndis (exotic species - hybrids) and Mabea fistulifera Mart. (native species) and the subplot treatments: Control; D0 - without fertilization; DM - mineral fertilizer according to crop need; DC - with compost manure according to crop need (10 t ha-1); D15 - 15 t ha-1 and D20 - 20 t ha-1 of the compound. In February of the years 2010 and 2011 were installed in the central region of each treatment two traps "pitt fall" which remained for seven days in the field. We calculated Shannon diversity and Pielou evenness indices, and richness of wildlife activity groups. The results were analyzed by ANOVA and Scott Knott test at 5% significance level. In 2010, the area with M. fistulifera, was captured a total of 2697 organisms distributed mainly in: Hymenoptera with 45.83% of the total collected, Collembola (36.93%), Hemiptera Heteroptera (6.56%). In the area with E. urograndis, 1938 organisms were captured, being 50.67% of the order Hymenoptera, Collembola 26.83%, 7.59% Hemiptera Heteroptera. It was found that there was no significant difference between treatments and between species for all variables. Collected in 2011 were 4970 organisms in 56.22% of the order Hymenoptera, Collembola 18.49% and 7.12% beetle in the area of M. fistulifera. In the area of E. urograndis were 4200 organisms, 55.29% (Hymenoptera), 23.79% (Collembola) and 5.86% (Coleoptera). It appears that the activity values and richness of the fauna groups were significantly higher in treatments with organic fertilization in both cultive. It is concluded that after one year there was a variation of the dominant

  7. Arsenic encapsulation using Portland cement with ferrous sulfate/lime and Terra-Bond™ technologies - Microcharacterization and leaching studies.

    Science.gov (United States)

    Randall, Paul M

    2012-03-15

    This work reports the results of an investigation on the treatment and encapsulation of arsenic-containing materials by Portland cement with ferrous sulfate and lime (PFL) and Terra-Bond™, a commercially available patented technology. The arsenic materials included: chromated copper arsenate (CCA)-treated wood materials; scorodite-rich mine tailings from the La Trinidad Mine in California; and a soil/smelter dust mixture from the Anaconda Superfund site spiked with monosodium methyl arsenate (MSMA) to simulate an organoarsenic soil material. SEM/EDS and XRD spectra of PFL treated samples showed similarity across all three waste materials while Terra-Bond treated samples showed predominance of elemental sulfur. SEM/EDS of PFL treated samples showed that calcium was imbedded in the structure while micrographs of Terra-Bond treated samples showed the appearance of an epoxy material on the surface. The epoxy material appears to be responsible for encapsulating and reducing the leachability of arsenic. XANES spectra for the PFL treatment of CCA-containing samples showed that arsenic has a predominant pentavalent form (As +5), and the PFL treatment process did not alter the arsenic oxidation state. But, distinct differences were observed for XANES spectra of untreated and PFL treated scorodite-rich mine tailing which changed the arsenic coordination structure from a mixture of As (+3/+5) to exclusively As (+5). Both S/S techniques reduced the amount of arsenic released in the leaching tests. Most cases show lower amounts of arsenic released from wastes treated by the Terra-Bond™ technique when compared to the PFL technique. The pH of the solution significantly affected the leachability, with the amount of arsenic released increasing with pH. Sequential extraction results indicate that sodium hydroxide was favorable in releasing arsenic in the mine tailings. This is due to ligand displacement reactions of hydroxyl ions with arsenic species and high pH conditions that

  8. Quality improvement of photopolimerizable-cement root canal obturation

    Science.gov (United States)

    Lupato Conrado, Luis A.; Frois, Iris M.; Amaro Zangaro, Renato; Munin, Egberto; Kuranaga, Carlos; Dias da Silva, Marcos; do Carmo de Andrade Nono, Maria; Cerquiera Rezende, Mirabel

    2003-06-01

    The sealing cements commonly used for endodontic applications are of the type cured through chemical reactions. During the polymerization process, mechanical contractions are not uncommon, leading to a non-perfect sealing. Photopolymerizable cements usually presents superior performance as compared to those chemically activated. However, difficulties in carrying the light to difficult-to-reach regions like the dental apex preclude those material of being accepted in the dental office routine. This work reports on a novel technique which allow the light curing of photopolymerizable cements in endodontic applications. A special light guide had been developed to allow the curing light to reach and polymerize the sealing cement in the apex region. The technique was tested by using single-root human teeth with normal canal morphology. The Ultradent EndoREZ root canal sealer and a resin-based photopolymerizable filler specially developed for the current application had been used. The cone-shaped light guide was introduced into treated canals filled with the photopolymerizable material, up to the apical region. Light from an argon laser was launched onto the light guide for polymerization. All test samples were immersed in methylene-blue solution for microleakage testing. All samples treated with the self-polymerizable material presented dye penetration to some extent. No sample within the group which had the filling material polymerized by using the light guide presented dye penetration through the canal wall.

  9. Manufacture and properties of fluoride cement

    Science.gov (United States)

    Malata-Chirwa, Charles David

    This research work aimed at characterising composition, hydration and physical properties of fluoride cement, by studying samples of the cement obtained from Malawi, and comparing them to ordinary Portland cement. By confirming the suitable characteristics of fluoride cement through this work, the results of the research work provide a good basis for the wider adoption of fluoride cement as an alternative to ordinary Portland cement, especially in developing economies. Numerous accounts have been cited regarding the production and use of fluoride cement. Since there have not been conclusive agreement as to its properties, this study was limited to the theories of successful incorporation of fluoride compounds in the manufacture of fluoride cement. Hence, the properties and characteristics reported in this study relate to the cement currently manufactured in Malawi, and, on a comparative basis only, to that manufactured in other parts of the world. Samples of the fluoride cement used in the study were obtained by synthetic manufacture of the cement using common raw materials for the manufacture of fluoride cement that is limestone, silica sand, and fluorspar. These samples were subjected to several comparative tests used to characterise cements including examination under x-ray diffractometer, scanning electron microscopy and tests for setting time and compressive strength. Under similar laboratory conditions, it was possible to prove that fluoride cement hardens more rapidly than ordinary Portland cement. Also observed during the experimental work is that fluoride cement develops higher compressive strengths than ordinary Portland cement. The hardening and setting times are significantly different between the two cements. Also the nature of the hydration products, that is the microstructural development is significantly different in the two cements. The differences brought about between the two cements are because of the presence of fluorine during the clinkering

  10. Effects of using pozzolan and Portland cement in the treatment of dispersive clay.

    Science.gov (United States)

    Vakili, A H; Selamat, M R; Moayedi, H

    2013-01-01

    Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable of reducing dispersion potential to almost zero percent in only 7 days; and a 2% cement content was capable of achieving similar result in 14 days. However, treatment by cement alone is costly and could jeopardize the long term performance. Thus, a combined 5% pozzolan and 1.5% cement content was found capable of reducing dispersion potential from 100% to zero percent in 14 days. The results indicate that although simultaneous treatment with pozzolan and cement would extend the required curing time in comparison to treatment by cement alone of a higher content, the task could still be carried out in a reasonable period of curing time while avoiding the drawbacks of using either pozzolan or cement alone.

  11. Hydration Characteristics and Immobilization of Cr (VI) in Slag Cement-CKD Pastes under Hydrothermal Treatment

    Institute of Scientific and Technical Information of China (English)

    M R Shatat; Gomaa A M Ali; M A Tantawy

    2015-01-01

    The effect of hydrothermal curing regimes on the hydration characteristics of slag cement containing different ratios of cement kiln dust has been studied. The samples for this study were combination of slag cement and cement kiln dust (5%-25%) without and with immobilization of 5% Cr (VI) by mass. Pastes were hydrothermally treated at 180℃ for different periods (2-24 h) in well closed stainless steel capsule. The hydration characteristics of these pastes were studied by measuring the compressive strength, bulk density, total porosity and combined water content. The findings were further supported by XRD and SEM analysis. The results indicated that the hydration characteristics of slag cement paste containing cement kiln dust 10% by mass were enhanced, especially at later ages (24 h) of hydration. That is due to the hydrothermal curing regimes of immobilized pastes accelerating hydration reactions and precipitation of CaCrO4, indicating that Cr (VI) can be solidiifed in the cement paste. This precipitation leads to pore formation in hydrated slag cement pastes.

  12. Effects of Using Pozzolan and Portland Cement in the Treatment of Dispersive Clay

    Directory of Open Access Journals (Sweden)

    A. H. Vakili

    2013-01-01

    Full Text Available Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable of reducing dispersion potential to almost zero percent in only 7 days; and a 2% cement content was capable of achieving similar result in 14 days. However, treatment by cement alone is costly and could jeopardize the long term performance. Thus, a combined 5% pozzolan and 1.5% cement content was found capable of reducing dispersion potential from 100% to zero percent in 14 days. The results indicate that although simultaneous treatment with pozzolan and cement would extend the required curing time in comparison to treatment by cement alone of a higher content, the task could still be carried out in a reasonable period of curing time while avoiding the drawbacks of using either pozzolan or cement alone.

  13. CT evaluation of local leakage of bone cement after percutaneous kyphoplasty and vertebroplasty

    Energy Technology Data Exchange (ETDEWEB)

    Lee, In Jae; Choi, A. Lam; Yie, Mi-Yeon; Yoon, Ji Young; Jeon, Eui Yong; Koh, Sung Hye; Yoon, Dae Young; Lim, Kyung Ja (Dept. of Radiology, Hallym Univ. Sacred Heart Hospital, Seoul (Korea)), e-mail: ijlee2003@medimail.co.kr; Im, Hyoung June (Dept. of Occupational Medicine, Hallym Univ. College of Medicine, Seoul (Korea))

    2010-07-15

    Background: Percutaneous injection of bone cement (acrylic cement) during percutaneous kyphoplasty and vertebroplasty can cause symptomatic or asymptomatic complications due to leakage, extravasation or vascular migration of cement. Purpose: To investigate and to compare the incidence and site of local leakage or complications of bone cement after percutaneous kyphoplasty and vertebroplasty using bone cement. Material and Methods: We retrospectively reviewed 473 cases of percutaneous kyphoplasty or vertebroplasty performed under fluoroscopic guidance. Of the 473 cases, follow-up CT scans that covered the treated bones were available for 83 cases (59 kyphoplasty and 24 vertebroplasty). Results: The rate of local leakage of bone cement was 87.5% (21/24) for percutaneous vertebroplasty and 49.2% (29/59) for kyphoplasty. The most common site of local leakage was perivertebral soft tissue (n=8, 38.1%) for vertebroplasty. The most common site of local leakage was a perivertebral vein (n=7, 24.1%) for kyphoplasty. Two cases of pulmonary cement embolism developed: one case after kyphoplasty and one case after vertebroplasty. Conclusion: Local leakage of bone cement was more common for percutaneous vertebroplasty compared with kyphoplasty (P<0.005). The most common sites of local leakage were perivertebral soft tissue and perivertebral vein.

  14. Effects of Using Pozzolan and Portland Cement in the Treatment of Dispersive Clay

    Science.gov (United States)

    Vakili, A. H.; Selamat, M. R.; Moayedi, H.

    2013-01-01

    Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable of reducing dispersion potential to almost zero percent in only 7 days; and a 2% cement content was capable of achieving similar result in 14 days. However, treatment by cement alone is costly and could jeopardize the long term performance. Thus, a combined 5% pozzolan and 1.5% cement content was found capable of reducing dispersion potential from 100% to zero percent in 14 days. The results indicate that although simultaneous treatment with pozzolan and cement would extend the required curing time in comparison to treatment by cement alone of a higher content, the task could still be carried out in a reasonable period of curing time while avoiding the drawbacks of using either pozzolan or cement alone. PMID:23864828

  15. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  16. Development of Multiple Cement Mixture and Its Applied Technology

    Science.gov (United States)

    Sun, Jie; Li, Qiaoling; Liu, Feng; Liu, Shipeng

    Currently, materials used to backfill grooves in municipal pipeline projects are pure soil and lime earth generally. Besides, punning or rolling compaction is used. Thus, it is difficult to compact or tamp haunches under pipes. Because of immersion of surface water and activities of underground water and as water inside pipes or underground structures leaks outward, fine-grained soil in backfill move with activities of underground water and collapse is caused for ground. This thesis mainly introduces multiple cement mixture and its performance.

  17. Use of lime cement stabilized pavement construction

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M.A.; Raju, G.V.R.P. [JNTU College of Engineering, Kakinada (India). Dept. of Civil Engineering

    2009-08-15

    Expansive clay is a major source of heave induced structural distress. Swelling of expansive soils causes serious problems and produce damages to many structures. Many research organizations are doing extensive work on waste materials concerning the feasibility and environmental suitability. Fly ash, a waste by product from coal burning in thermal power stations, is abundant in India causing severe health, environmental and disposal problems. Attempts are made to investigate the stabilization process with model test tracks over expansive subgrade in flexible pavements. Cyclic plate load tests are carried out on the tracks with chemicals like lime and cement introduced in fly ash subbase laid on sand and expansive subgrades. Test results show that maximum load carrying capacity is obtained for stabilized fly ash subbase compared to untreated fly ash subbase.

  18. Cementation of Loose Sand Particles based on Bio-cement

    Institute of Scientific and Technical Information of China (English)

    RONG Hui; QIAN Chunxiang

    2014-01-01

    Loose sand particles could be cemented to sandstone by bio-cement (microbial induced magnesium carbonate). The bio-sandstone was firstly prepared, and then the compressive strength and the porosity of the sandstone cemented by microbial induced magnesium carbonate were tested to characterize the cementation effectiveness. In addition, the formed mineral composition and the microstructure of bio-sandstone were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The experimental results show that the feasibility of binding loose sand particles using microbial induced magnesium carbonate precipitation is available and the acquired compressive strength of bio-sandstone can be excellent at certain ages. Moreover, the compressive strength and the porosity could be improved with the increase of microbial induced magnesium carbonate content. XRD results indicate that the morphology of magnesium carbonate induced by microbe appears as needles and SEM results show that the cementation of loose sand particles to sandstone mainly relies on the microbial induced formation of magnesium carbonate precipitation around individual particles and at particle-particle contacts.

  19. Leachability and strength of kaolin stabilized with cement and rubber

    Directory of Open Access Journals (Sweden)

    Meei-Hoan Ho

    2011-07-01

    Full Text Available Yearly, the disposal of used tyres is a major environmental problem for countries all over the world. This causes environmental hazards such as uncontrolled fire, consume landfill space, breeding ground for mosquitoes and contaminating the soil and vegetation. Hence, urgent steps were identified to produce new methods of recycling the waste tyres to solve this hazard. This study reviews the feasibility of using waste tyres in the form of rubber chips with cement to stabilize soft clay and the effect to the environment. The focus of this study was mainly the strength and leachability characteristics of kaolin as base clay, admixed with cement as the binder and rubber chips as an additive. Leaching test is used to evaluate the performance of cementitious materials for stabilization and solidification (S & S of hazardous materials such as waste or contaminated soil. In this study, cylindrical stabilized clay specimens were prepared with various rubber chips contents and cement, and then aged for 28 days. Cylindrical specimens were then subjected to unconfined compressive strength test (using Geocomp LoadTrac II and the specimens were later dried in oven at 105° before tested for leaching tests. These leaching methods are Acid Neutralization Capacity Test (ANC and Synthetic Precipitation Leaching Procedure (SPLP. The solidified samples were checked on six different heavy metals, namely copper, chromium, cadmium, arsenic, zinc and plumbum. Analysis was carried out by relating the effects of 0, 2 or 4 % cement as well as 0, 5, 10 and 15 % rubber chips addition to the base clay and its leachability. As observed, the curing of specimen for 28 days was in a range of 66.24 to 249.4 kPa. Specimen with 4 % cement is able to produce ANC9 of about 0.13 meq HNO3/g specimen. However specimen with 0 % and 2 % cement for different rubberchips content shows that the specimen do not have the capacity to neutralize acid at pH 9. Therefore, more cement (> 4 % is

  20. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.”...

  1. Application of Bacillus subtilis 168 as a multifunctional agent for improvement of the durability of cement mortar.

    Science.gov (United States)

    Park, Sung-Jin; Park, Jong-Myong; Kim, Wha-Jung; Ghim, Sa-Youl

    2012-11-01

    Microbiological calcium carbonate precipitation (MCCP) has been investigated for its ability to improve the durability of cement mortar. However, very few strains have been applied to crack remediation and strengthening of cementitious materials. In this study, we report the biodeposition of Bacillus subtilis 168 and its ability to enhance the durability of cement material. B. subtilis 168 was applied to the surface of cement specimens. The results showed a new layer of deposited organic-inorganic composites on the surface of the cement paste. In addition, the water permeability of the cement paste treated with B. subtilis 168 was lower than that of non-treated specimens. Furthermore, artificial cracks in the cement paste were completely remediated by the biodeposition of B. subtilis 168. The compressive strength of cement mortar treated with B. subtilis 168 increased by about 19.5% when compared with samples completed with only B4 medium. Taken together, these findings suggest that the biodeposition of B. subtilis 168 could be used as a sealing and coating agent to improve the strength and water resistance of concrete. This is the first paper to report the application of Bacillus subtilis 168 for its ability to improve the durability of cement mortar through calcium carbonate precipitation.

  2. Natural Radioactivity in Tanzania Cements and their Raw Materials

    Directory of Open Access Journals (Sweden)

    Aloyce Isaya Amasi

    2014-10-01

    Full Text Available This paper presents the study of natural radioactivity in Tanzania Portland cements and their raw materials. Samples collected as raw materials were pozzolan, sandstone, limestone, clay, gypsum and cement as finished products. The natural radioactivity due to the presence of radium 226Ra, thorium 232Th and potassium 40K were measured by means of gamma spectrometer coupled with HPGe detector. The mean measured activity concentrations of 226Ra, thorium 232Th and potassium 40K in the raw materials range from 2.6 to 93.2, 1.3 to 172.8 and 6.3 to 997 Bq/kg, respectively with higher activity concentrations in pozzolan and lower in gypsum. Activity concentrations of natural radionuclides in raw materials (excluding some materials from Songwe deposits in Mbeya region are comparative with the worldwide average concentrations of these radionuclides in soil. The average activity concentration of 226Ra, thorium 232Th and potassium 40K in the cements are 46, 28 and 228 Bq/kg, respectively. The calculated values of radiological indices are below 60% of the upper recommended values for building materials. The average annual effective dose to an occupant from use of these materials equals to 0.45 mSv. Average activity concentrations of the mentioned radionuclides in Tanzania cements are in the middle of the variability interval of the national averages.

  3. Effects of Using Pozzolan and Portland Cement in the Treatment of Dispersive Clay

    OpenAIRE

    Vakili, A. H.; Selamat, M. R.; H. Moayedi

    2013-01-01

    Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable o...

  4. Effects of Mechanical and Chemical Pretreatments of Zirconia or Fiber Posts on Resin Cement Bonding

    OpenAIRE

    Rui Li; Hui Zhou; Wei Wei; Chen Wang,; Ying Chun Sun; Ping Gao

    2015-01-01

    The bonding strength between resin cement and posts is important for post and core restorations. An important method of improving the bonding strength is the use of various surface pretreatments of the post. In this study, the surfaces of zirconia (fiber) posts were treated by mechanical and/or chemical methods such as sandblasting and silanization. The bonding strength between the zirconia (fiber) post and the resin cement was measured by a push-out method after thermocycling based on the ad...

  5. Radioactive wastes dispersed in stabilized ash cements

    International Nuclear Information System (INIS)

    One of the most widely-used methods for the solidification/stabilization of low-level radwaste is by incorporation into Type-I/II ordinary portland cement (OPC). Treating of OPC with supercritical fluid carbon dioxide (SCCO2) has been shown to significantly increase the density, while simultaneously decreasing porosity. In addition, the process significantly reduces the hydrogenous content, reducing the likelihood of radiolytic decomposition reactions. This, in turn, permits increased actinide loadings with a concomitant reduction in disposable waste volume. In this article, the authors discuss the combined use of fly-ash-modified OPC and its treatment with SCCO2 to further enhance immobilization properties. They begin with a brief summary of current cement immobilization technology in order to delineate the areas of concern. Next, supercritical fluids are described, as they relate to these areas of concern. In the subsequent section, they present an outline of results on the application of SCCO2 to OPC, and its effectiveness in addressing these problem areas. Lastly, in the final section, they proffer their thoughts on why they believe, based on the OPC results, that the incorporation of fly ash into OPC, followed by supercritical fluid treatment, can produce highly efficient wasteforms

  6. Radioactive wastes dispersed in stabilized ash cements

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, J.B.; Taylor, C.M.V.; Sivils, L.D.; Carey, J.W.

    1997-12-31

    One of the most widely-used methods for the solidification/stabilization of low-level radwaste is by incorporation into Type-I/II ordinary portland cement (OPC). Treating of OPC with supercritical fluid carbon dioxide (SCCO{sub 2}) has been shown to significantly increase the density, while simultaneously decreasing porosity. In addition, the process significantly reduces the hydrogenous content, reducing the likelihood of radiolytic decomposition reactions. This, in turn, permits increased actinide loadings with a concomitant reduction in disposable waste volume. In this article, the authors discuss the combined use of fly-ash-modified OPC and its treatment with SCCO{sub 2} to further enhance immobilization properties. They begin with a brief summary of current cement immobilization technology in order to delineate the areas of concern. Next, supercritical fluids are described, as they relate to these areas of concern. In the subsequent section, they present an outline of results on the application of SCCO{sub 2} to OPC, and its effectiveness in addressing these problem areas. Lastly, in the final section, they proffer their thoughts on why they believe, based on the OPC results, that the incorporation of fly ash into OPC, followed by supercritical fluid treatment, can produce highly efficient wasteforms.

  7. A modified PMMA cement (Sub-cement) for accelerated fatigue testing of cemented implant constructs using cadaveric bone.

    Science.gov (United States)

    Race, Amos; Miller, Mark A; Mann, Kenneth A

    2008-10-20

    Pre-clinical screening of cemented implant systems could be improved by modeling the longer-term response of the implant/cement/bone construct to cyclic loading. We formulated bone cement with degraded fatigue fracture properties (Sub-cement) such that long-term fatigue could be simulated in short-term cadaver tests. Sub-cement was made by adding a chain-transfer agent to standard polymethylmethacrylate (PMMA) cement. This reduced the molecular weight of the inter-bead matrix without changing reaction-rate or handling characteristics. Static mechanical properties were approximately equivalent to normal cement. Over a physiologically reasonable range of stress-intensity factor, fatigue crack propagation rates for Sub-cement were higher by a factor of 25+/-19. When tested in a simplified 2 1/2-D physical model of a stem-cement-bone system, crack growth from the stem was accelerated by a factor of 100. Sub-cement accelerated both crack initiation and growth rate. Sub-cement is now being evaluated in full stem/cement/femur models. PMID:18774136

  8. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    LENUS (Irish Health Repository)

    Addison, Owen

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic.

  9. Synthesis and Evaluation of Some Polymeric Surfactants for Treating Crude Oil Emulsions Part :1 Treatment of Sandy Soil Polluted with Crude oil by Monomeric and Polymeric Surfactants

    International Nuclear Information System (INIS)

    In the present work, five surfactants were prepared ; two of them were monomeric surfactants, one was anionic ( tri- ethanol ammonium salt of dodecyl benzene sulfonic acid. E1) and the second was non-ionic surfactant ( nonyl phenol ethoxylate, E2 ). The other three surfactants were polymeric non-ionic surfactants ( ethoxylated phenol formaldehyde mono-ethanol amine E3, ethoxylated poly nonyl phenol formaldehyde diethanol amine E4, and ethoxylated nonyl phenol formaldehyde triethanol amine E5). The gel permeation chromatography (GPC) and the elemental analysis were carried out to determine the molecular weight of the polymeric surfactants. The surface properties for these surfactants were determined by measuring the surface tension, the foaming power, cloud point and the emulsification power. The polymeric surfactants were used to treat the polluted Sandy soil, which saturated with two type of crude oils ( waxy and asphaltenic). From the data obtained, it was found that the increasing of surfactant concentrations led to increase the reclamation of the waxy and asphaltinic crude oil percentages and decreased the interfacial tension. The reclaimed oil percentage increased with decreasing the HLB value of non-ionic surfactant. In general behavior, the reclamation of the asphaltenic crude oil was greater than the reclamation of the waxy crude oil. The data were discussed in the light of the chemical structure of the surfactants and composition of crude oil

  10. Cement radwaste solidification studies third annual report

    International Nuclear Information System (INIS)

    This report summarises cement radwaste studies carried out at AEE Winfrith during 1981 on the encapsulation of medium and low active waste in cement. During the year more emphasis has been placed on the work which is directly related to the solidification of SGHWR active sludge. Information has been obtained on the properties of 220 dm3 drums of cemented waste. The use of cement grouts for the encapsulation of solid items has also been investigated during 1981. (U.K.)

  11. The effect of timing temporary cements to treat induced pulp necrosis in the teeth of dogs Uso do "curativo de demora" em diferentes tempos no tratamento endodôntico de cães com necrose pulpar induzida

    Directory of Open Access Journals (Sweden)

    Léslie M. Domingues-Falqueiro

    2007-02-01

    Full Text Available During endodontic therapy (pulpectomy, root canal debridement and root canal filling microbiological management is a major concern. Bacteria present in dentine tubules, apical foramina and apical delta are causally related to failure of the procedure. Studies have shown that during single session endodontic treatment bacteria remain within dental structures. The aim of the present study was to evaluate endodontic treatment performed as two sessions, using temporary endodontic dressing materials for different periods in four groups of experimental dogs. A total of 80 roots of second and third upper premolar teeth and second, third and fourth lower premolar teeth were divided into four groups. The pulp chamber was opened with burrs and the pulp exposed for 60 days to induce pulpal inflammation and necrosis. Groups II, III and IV were treated with calcium hydroxide plus camphorated paramono-chlorophenol (PMCC for 7, 15 and 30 days, respectively. In all groups, the root canals were filled with zinc oxide-eugenol and gutta-percha cones. Clinical and radiographical measurements were performed every 2 weeks. After 60 days a small block section containing the teeth, surrounding periapical tissues and the periodontium was removed for histological and microbiological study. Histological analysis revealed intense inflammatory response in all groups. Microbiological analysis showed microbial reduction inversely proportional to the period of time that the intracanal temporary medicament was left in place.Em um tratamento endodôntico, a microbiota é o ponto primordial a ser levado em consideração, pois as bactérias presentes nos túbulos dentinários, nas foraminas e no delta apical em cães estão relacionadas aos insucessos do procedimento. Estudos revelam que tratamentos realizados em uma única sessão ainda permitem a permanência de bactérias nas estruturas dentárias, portanto propõe-se a execução em duas sessões, com diferentes tempos de

  12. Neutron Scattering Studies of Cement

    Science.gov (United States)

    Allen, Andrew

    2010-03-01

    Despite more than a century of research, basic questions remain regarding both the internal structure and the role of water in Ordinary Portland cement (OPC) concrete, the world's most widely used manufactured material. Most such questions concern the primary hydration product and strength-building phase of OPC paste, the calcium silicate hydrate (C-S-H) gel. When cement and water are mixed, this phase precipitates as clusters of nanoscale (nearly amorphous) colloidal particles with an associated water-filled inter-particle pore system. Most attempts to characterize the C-S-H gel and the behavior of the associated water involve drying or other processes that, themselves, change the bound water content within and around the gel. Neutron scattering methods do not suffer from this disadvantage. Furthermore, the neutron isotope effect and the neutron's sensitivity to molecular motion have enabled considerable progress to be made in recent years by: (i) determining the C-S-H composition, density and gel structure in small-angle neutron scattering (SANS) H/D contrast variation studies; (ii) elucidating the changing state of water within cement as hydration progresses using quasielastic neutron scattering (QENS); and (iii) measuring the production and consumption of nanoscale calcium hydroxide (CH), a by-product of cement hydration that co-exists with the C-S-H gel, using inelastic neutron scattering (INS). These experiments have provided new insights into the physics and chemistry of cement hydration, and have implications for the design of new concretes with pozzolanic cement additions that are intended to address environmental concerns and sustainability issues.

  13. PERFORMANCE OF PULVERIZED SLAG-SUBSTITUTED CEMENT

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.

  14. 21 CFR 872.3275 - Dental cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns...

  15. Fluid sign in the treated bodies after percutaneous vertebroplasty

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chao-Chun [China Medical University Hospital, Department of Radiology, Taichung (China); China Medical University, Department of Biomedical Imaging and Radiological Science, College of Health Care, Taichung (China); Buddhist Tzu Chi General Hospital and Tzu Chi University, Department of Medical Imaging, Hualien (China); Yen, Pao-Sheng [Buddhist Tzu Chi General Hospital and Tzu Chi University, Department of Medical Imaging, Hualien (China); Wen, Shu-Hui [Tzu Chi University, Department of Public Health, Hualien (China)

    2008-11-15

    The aims of this study are to describe non-healing in the treated vertebral body after percutaneous vertebroplasty and analyze the influence of vacuum cleft, location, and severity of collapse on the development of nonunion cement. Of 208 patients (266 treated vertebral bodies) who were treated with percutaneous vertebroplasty from September 2002 to May 2006, 23 patients (41 treated levels) with residual or recurrent pain underwent follow-up magnetic resonance imaging (MRI) study. Retrospective chart review with analysis of preoperative and postoperative MRIs were performed in these 23 patients. In the 41 treated vertebral bodies, 22 of 41 bodies had vacuum cleft found in the preoperative MRI study. Eight of the 22 treated vertebral bodies with preoperative vacuum clefts were found to have fluid between the interface of cement and the residual bone in the collapsed vertebral bodies on follow-up MRI. The adjacent discs of these treated vertebral bodies were upward/downward displaced. The endplate of the adjacent vertebral body exhibited fibrotic change. Treated bodies with vacuum clefts and level A location (T9, T11, T12, and L1) had higher probability of developing nonunion of the cement with statistical significance. The probability of nonunion cement in severe collapsed bodies might be higher than that of union cement in mild collapsed ones, but was not statistically significant. Fluid sign in the treated body represents unhealed bone-cement interface. The location of the treated vertebral body and existence of vacuum cleft in the treated bodies may be important factors influencing the nonunion of cement. (orig.)

  16. ADVANCED CEMENTS FOR GEOTHERMAL WELLS

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well

  17. Microscale Investigation of Arsenic Distribution and Species in Cement Product from Cement Kiln Coprocessing Wastes

    OpenAIRE

    Yufei Yang; Jingchuan Xue; Qifei Huang

    2013-01-01

    To improve the understanding of the immobilization mechanism and the leaching risk of Arsenic (As) in the cement product from coprocessing wastes using cement kiln, distribution and species of As in cement product were determined by microscale investigation methods, including electron probe microanalysis (EPMA) and X-ray absorption spectroscopy. In this study, sodium arsenate crystals (Na3AsO412H2O) were mixed with cement production raw materials and calcined to produce cement clinker. Then, ...

  18. The comparison between sulfate salt weathering of portland cement paste and calcium sulfoaluminate cement paste

    OpenAIRE

    Liu, Zanqun; Deng, Dehua; De Schutter, Geert

    2015-01-01

    In this paper, the damage performances of sulfate salt weathering of Portland cement paste and calcium sulfoaluminate (CSA) cement paste were compared according to authors' previous studies. It was found that the evaporation zone of speciments partially immersed in 10% Na2SO4 solution were both severely deteriorated for Portland cement and CSA cement. However, the differences were more significant: (1) the CSA cement paste were damaged just after 7 days exposure compared to the 5 months expos...

  19. High piezoelectric properties of cement piezoelectric composites containing kaolin

    Science.gov (United States)

    Pan, Huang Hsing; Yang, Ruei-Hao; Cheng, Yu-Chieh

    2015-04-01

    To obtain high piezoelectric properties, PZT/cement composites with kaolin were fabricated and polarized by 1.5kV/mm electric field for 40 min, where lead zirconate titanate (PZT) inclusion with 50% by volume was used. After the polarization, piezoelectric properties of the composite were measured daily till 100 days. Results indicated that relative dielectric constant (ɛr) and piezoelectric strain constant (d33) increase with aging day, and approach to asymptotic values after 70 days. Temperature treatment to the composite is a dominate factor to enhance piezoelectric properties. The d33 and ɛr values of PZT/cement composites treated at the ambient temperature (23℃) were 57pC/N and 275 at the 70th aging day respectively, and then reached 106pC/N and 455 in turn with 150℃ treatment. The composite contains 4% kaolin having the highest value of d33=111pC/N and ɛr=500 at 90 days because the porosity is the less than the others. Cement piezoelectric composites containing kaolin own the higher d33 and ɛr value, compared with the other reported composites with 50% PZT. The porosity, the electromechanical coupling factor and impedance-frequency spectra of the cement piezoelectric composites were also discussed.

  20. Feasibility of Pulverized Oyster Shell as a Cementing Material

    Directory of Open Access Journals (Sweden)

    Chou-Fu Liang

    2013-01-01

    Full Text Available This research intends to study the cementing potential of pulverized oyster shell, rich in calcium, when mixed with fly ash and soil. Cylindrical compacted soil and cubic lime specimens with different proportions of the shells and fly ash are made to study the strength variance. Soil, which is classified as CL in the USCS system, commercialized pulverized oyster shell, F-type fly ash, and lime are mixed in different weight percentages. Five sample groups are made to study the compressive strength of soil and lime specimens, respectively. The lime cubes are made with 0.45 W/B ratio and the cylindrical soils are compacted under the standard Procter compaction process with 20% moisture content. The results show that increment of shell quantity result to lower strength on both the soil and lime specimens. In a 56-day curing, the compressive strength of the lime cubes containing fly ash increases evidently while those carrying the shell get little progress in strength. The soil specimens containing fly ash gradually gain strength as curing proceeds. It suggests that mixtures of the shell and fly ash do not process any Pozzolanic reaction nor help to raise the unconfined strength of the compacted soil through the curing.

  1. INFLUENCE OF POZZOLANA ON THE HYDRATION OF C4AF RICH CEMENT IN CHLORIDE ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    IRMANTAS BARAUSKAS

    2013-03-01

    Full Text Available This study investigated the influence of natural pozzolana - opoka additive on the hydration of C4AF rich cement and the effects of chloride ions on the hydrates formed. In the samples, 25 % (by weight of the sintered C4AF rich cement and OPC was replaced with pozzolana. The mixtures were hardened for 28 days in water, soaked in a saturated NaCl solution for 3 months at 20°C. It was estimated that under normal conditions, pozzolana additive accelerates the hydration of calcium silicates and initiates the formation of CO32- - AFm in the Brownmillerite rich cement. However, the hydration of Brownmillerite cement with opoka additive is still slower to compare with hydration of Portland cement. Also, opoka decreases total porosity and threshold pore diameter of Brownmillerite cement paste after two days of hydration. After 28 days of hydration threshold pore diameter became smaller even to compare with threshold pore diameter of Portland cement. Opoka additive promotes the formation of Friedel’s salt in Brownmillerite samples treated in saturated NaCl solution, because CO32-–AFm affected by saturated NaCl solution become unstable and takes part in reactions producing Friedel’s salt.

  2. Blended Cements Produced With Synthetic Zeolite Made from Industrial By-Product

    Directory of Open Access Journals (Sweden)

    Vitoldas Vaitkevičius

    2015-03-01

    Full Text Available Zeolites are appropriate supplementary cementitious materials in cement and concrete industry. In the present work synthetic zeolites was used like supplementary material in hardened cement paste and some properties as well as its influence on Portland cement hydration was determinate. X-ray powder diffraction, scanning electronic microscopy and energy-dispersive X-ray spectroscopy, FTIR spectroscopy were used as investigation methods. The compressive strength of hardened cement paste was measured at day 3, 28 and 60. The instrumental analysis showed that zeolite A(Na dominates and unreacted Al(OH3 remains in investigated synthetics zeolites, made from thermal and mechanical treated AlF3 production waste. The Chapelle test showed that both zeolites have good pozzolanic properties. The samples compressive strength remained close to the control samples compressive strength, reducing the amount of Portland cement, i.e., changing it by zeolite. After 60 days, the compressive strength was the best in the samples where 5% of Portland cement was replaced by the 2-zeolite. The compressive strength of the samples increased by 9 % compared with control samples. This research provides a real opportunity to save cement thus disposing the waste.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5635

  3. Thoughts on the Current Cement Industry Development

    Institute of Scientific and Technical Information of China (English)

    Gan Zhihe

    2003-01-01

    According to the analysis of cement capacity andits relations with macro economy running index, the mainreasons for the present rapid development of cement capacityare the rapid development of economy and the shot up ofwhole society fixed asset investment. According to the presentspeed of economy development, cement still enjoys a po-tential increase, So here has not been an overall excessivepopularity of cement industry. The best way to prevent lowlevel repeated construction is to promote the development ofnew dry- process cement as well as try to get rid of blindness.

  4. Effect of temporary cements on the shear bond strength of luting cements

    Directory of Open Access Journals (Sweden)

    Marco Fiori-Júnior

    2010-02-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate, by shear bond strength (SBS testing, the influence of different types of temporary cements on the final cementation using conventional and self-etching resin-based luting cements. Material and Methods: Forty human teeth divided in two halves were assigned to 8 groups (n=10: I and V (no temporary cementation; II and VI: Ca(OH2-based cement; III and VII: zinc oxide (ZO-based cement; IV and VIII: ZO-eugenol (ZOE-based cement. Final cementation was done with RelyX ARC cement (groups I to IV and RelyX Unicem cement (groups V to VIII. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. RESULTS: Means were (MPa: I - 3.80 (±1.481; II - 5.24 (±2.297; III - 6.98 (±1.885; IV - 6.54 (±1.459; V - 5.22 (±2.465; VI - 4.48 (±1.705; VII - 6.29 (±2.280; VIII - 2.47 (±2.076. Comparison of the groups that had the same temporary cementation (Groups II and VI; III and VII; IV and VIII showed statistically significant difference (p0.05 for the different luting cements (RelyX TM ARC and RelyX TM Unicem. The groups that had no temporary cementation (Groups I and V did not differ significantly from each other either (p>0.05. CONCLUSION: When temporary cementation was done with ZO- or ZOE-based cements and final cementation was done with RelyX ARC, there was an increase in the SBS compared to the control. In the groups cemented with RelyX Unicem, however, the use of a ZOE-based temporary cement affected negatively the SBS of the luting agent used for final cementation.

  5. False set in aireated cements

    Directory of Open Access Journals (Sweden)

    Vázquez, T.

    1986-06-01

    Full Text Available The influence of aireation on the appearance or elimination of the false setting in industrial portland cements is studied by means of infrared spectroscopy.

    Se estudia por medio de la espectroscopia infrarroja la influencia de la aireación sobre la aparición o eliminación del fraguado, en cemento portland industriales.

  6. Effects of composition and exposure on the solar reflectance of Portland cement concrete

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem

    2001-12-21

    Increasing the solar reflectance (albedo) of a paved surface keeps it cooler in the sun, reducing convection of heat from pavement to air and thereby decreasing the ambient air temperature. Simulations of the influence of pavement albedo on air temperature in Los Angeles predict that increasing the albedo of 1,250 km2 of pavement by 0.25 would save cooling energy worth $15M yr-1, and reduce smog-related medical and lost-work expenses by $76M yr-1. Most sidewalks and a small fraction of roads and parking areas are paved with portland cement concrete, which can be made quite reflective through suitable choice of cement and aggregate. Variations with composition and environmental exposure of the albedos of portland cement concrete pavements were investigated through laboratory fabrication and exposure of 32 mixes of concrete. Twenty-four mixes yielded substandard, ''rough'' concretes due to high, unmet aggregate water demand. The albedos of the remaining eight ''smooth'' concrete mixes ranged from 0.41 to 0.77 (mean 0.59). Simulated weathering, soiling, and abrasion each reduced average concrete albedo (mean decreases 0.06, 0.05, and 0.19, respectively), though some samples became slightly more reflective through weathering or soiling. Simulated rain (wetting) strongly depressed the albedos of concretes (mean decrease 0.23) until their surfaces were dried. Concrete albedo grew as the cement hydration reaction progressed (mean increase 0.08), but stabilized within six weeks of casting. White-cement concretes were on average significantly more reflective than gray-cement concretes. The albedo of the most-reflective white-cement concrete was 0.18 to 0.39 higher than that of the most-reflective gray-cement concrete, depending on state of exposure. Concrete albedo generally correlated with cement albedo and sand albedo, and, after abrasion, with rock albedo. Cement albedo had a disproportionately strong influence on the reflectance

  7. Remediação de solos tratados com lodo rico em zinco Reclamation of soils treated with sewage sledge rich in Zn

    Directory of Open Access Journals (Sweden)

    Aline A. Mesquita

    2006-09-01

    Full Text Available Esta pesquisa teve por objetivos: estudar as alterações na distribuição de Zn nas diferentes frações químicas de solos tratados com lodo de esgoto, provocadas pela aplicação de carbonatos, óxidos e fosfatos para determinar a eficiência desses produtos na contenção desse elemento, e avaliar a redução de solubilidade através do uso de planta hiperacumuladora. Utilizou-se lodo de esgoto de indústria aplicado em amostras da camada superficial de um Latossolo Vermelho-Amarelo (LVA e de um Argissolo Vermelho-Amarelo (PVA. A adição de CaCO3 provocou imobilização química do Zn por sua associação às frações químicas mais estáveis. O FeCl3 + EDTA causou dissolução de compostos de Zn e dessorção desses elementos complexados por grupos funcionais de superfície. O KH2PO4 não alterou a distribuição de Zn nas diferentes formas químicas nos solos. O Zn concentrou-se nas raízes, limitando a passagem desses elementos para a parte aérea. Encontrou-se, nos tratamentos com o CaCO3, menor concentração de Zn na raiz e parte aérea. A adição de FeCl3 + EDTA promoveu aumento da concentração de Zn nesses órgãos da planta.This research had as objectives: to study the alterations in the distribution of Zn in different chemical carbonates fractions of soil treated with sewage sludge, caused by the application of carbonates, oxides and phosphates to determine the efficiency of these products in the contention of this element; and to evaluate the solubility reduction through the use of hyper accumulator plant. Industrial sewage sludge was applied in samples of surface layer of a Yellow Red Latossol and Yellow Red Argissol. The addition of CaCO3 caused chemical immobilization of Zn due to association of these elements with more stable chemical fractions. The FeCl3 + EDTA caused dissolution of Zn compounds and dessorption of these elements quelated by surface functional groups. The KH2PO4 did not alter the distribution of Zn in

  8. Pressurization of bioactive bone cement in vitro.

    Science.gov (United States)

    Fujita, H; Iida, H; Kawanabe, K; Okada, Y; Oka, M; Masuda, T; Kitamura, Y; Nakamura, T

    1999-01-01

    We have developed a bioactive bone cement consisting of MgO-CaO-SiO2-P2O5-CaF2 glass-ceramic powder (AW glass-ceramic powder), silica glass powder as an inorganic filler, and bisphenol-a-glycidyl methacrylate (bis-GMA) based resin as an organic matrix. The efficacy of this bioactive bone cement was investigated by evaluating its pressurization in a 5-mm hole and small pores using a simulated acetabular cavity. Two types of acetabular components were used (flanged and unflanged sockets) and a commercially available polymethylmethacrylate (PMMA) bone cement (CMW 1 Radiopaque Bone Cement) was selected as a comparative control. Bioactive bone cement exerted greater intrusion volume in 5-mm holes than PMMA bone cement in both the flanged and unflanged sockets 10 minutes after pressurization (p anchor holes than PMMA bone cement.

  9. Leaching of tritium from a cement composite

    International Nuclear Information System (INIS)

    Leaching of tritium from cement composites into an aqueous phase has been studied to evaluate the safety of incorporation of the tritiated liquid waste into cement. Leaching tests were performed by the method recommended by the International Atomic Energy Agency. The Leaching fraction was measured as functions of waste-cement ratio (Wa/C), temperature of leachant and curing time. The tritium leachability of cement in the long term test follows the order: alumina cement portland cement slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than synthetic sea water. The amount leached of tritium from a 200 l drum size specimen was estimated on the basis of the above results. (author)

  10. Understanding cement mechanical behavior in SAGD wells

    Energy Technology Data Exchange (ETDEWEB)

    Xie, J.; Zahacy, T. A. [C-FER Technologies (Canada)

    2011-07-01

    In the heavy oil industry, the steam assisted gravity drainage process is often used to enhance oil recovery but it can cause cracks in the cement sheath. These cracks are the result of high steam temperatures and thermal expansion. In order to mitigate this risk, improved well designs are required. The aim of this paper is to present the mechanical behavior of the cement sheath during the heating phase. An analysis of the impact of design and operating parameters was conducted through thermal hydraulic and thermal mechanical analyses to assess cement integrity. These analyses were then performed on an example of an SAGD project in the southern part of the Athabasca oilsands region to assess the performance of the cement sheath. Results showed that potential damage to the cement can be reduced by slow heating and a lower Young's modulus cement blend. This paper makes recommendations for optimizing cement design in thermal recovery wells.

  11. Rheology of cement grout  : Ultrasound based in-line measurement technique and grouting design parameters

    OpenAIRE

    Rahman, Mashuqur

    2015-01-01

    Grouting is performed in order to decrease the permeability and increase the stiffness of the material, especially soil and rock. For tunnelling and underground constructions, permeation grouting is done where cement based materials are pumped inside drilled boreholes under a constant pressure, higher than the ground water pressure. The aim of permeation grouting is to reduce the water flow into tunnels and caverns and to limit the lowering of the surrounding groundwater table. Cement based m...

  12. Effects of lime and cement treatment on the physicochemical, microstructural and mechanical characteristics of a plastic silt

    OpenAIRE

    LEMAIRE, Kevin; Deneele, Dimitri; BONNET, Stéphanie; LEGRET, Michel

    2013-01-01

    Stabilization using lime and cement is a widespread technique that provides civil engineering applications for soils with poor geotechnical performance. This article describes the effects of a combined lime+cement treatment on both the characteristics and properties of a plastic silt. A multi-scale approach was implemented and themechanical, microstructural and physicochemical changeswere investigated. To carry out these tasks, unconfined compressive strength measurements were conducted. The ...

  13. Shear bond strength of two resin cements to human root dentin using three dentin bonding agents.

    Science.gov (United States)

    Gogos, C; Stavrianos, C; Kolokouris, I; Economides, N; Papadoyannis, I

    2007-01-01

    This study compared the bond strength of two resin cements to human root dentin when used with three bonding agents. The materials used were Rely X ARC and Perma Cem, two one-bottle bonding agents (Single Bond, Bond-1) and one self-etching bonding agent (Clearfil SE Bond). The dentin was obtained from single rooted human teeth, and the specimens were treated with either 15% EDTA or 37% phosphoric acid to remove the smear layer, except in groups where the self-etching bonding agent was used. The resin cements were placed on dentin surfaces with the use of bonding agents. Shear bond strength (SBS) was tested using a single plane shear test assembly. The dentin specimens were divided into 10 groups. Eight groups were pre-treated with EDTA or phosphoric acid to remove the smear layer, followed by a bonding agent (Bond-1 or Single Bond) and resin cement (Rely X or Perma Cem). In the two remaining groups, the smear layer was left intact, and the two resins cements were used in combination with the self-etching bonding agent (Clearfil SE Bond). No statistically significant differences were observed among the eight groups treated with one-bottle bonding agents. The mean bond strengths of the two groups treated with the self-etching bonding agent did not differ significantly from each other but were both significantly greater than the bond strengths of all the other groups. The results of this study also showed that EDTA can be used as an alternative to phosphoric acid in bonding procedures for resin cements. However, the bond strengths of resin cements, in combination with a self-etching bonding agent, were significantly greater than those of the same cements when used with one-bottle bonding agents.

  14. Mesoscale texture of cement hydrates.

    Science.gov (United States)

    Ioannidou, Katerina; Krakowiak, Konrad J; Bauchy, Mathieu; Hoover, Christian G; Masoero, Enrico; Yip, Sidney; Ulm, Franz-Josef; Levitz, Pierre; Pellenq, Roland J-M; Del Gado, Emanuela

    2016-02-23

    Strength and other mechanical properties of cement and concrete rely upon the formation of calcium-silicate-hydrates (C-S-H) during cement hydration. Controlling structure and properties of the C-S-H phase is a challenge, due to the complexity of this hydration product and of the mechanisms that drive its precipitation from the ionic solution upon dissolution of cement grains in water. Departing from traditional models mostly focused on length scales above the micrometer, recent research addressed the molecular structure of C-S-H. However, small-angle neutron scattering, electron-microscopy imaging, and nanoindentation experiments suggest that its mesoscale organization, extending over hundreds of nanometers, may be more important. Here we unveil the C-S-H mesoscale texture, a crucial step to connect the fundamental scales to the macroscale of engineering properties. We use simulations that combine information of the nanoscale building units of C-S-H and their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles. We compute small-angle scattering intensities, pore size distributions, specific surface area, local densities, indentation modulus, and hardness of the material, providing quantitative understanding of different experimental investigations. Our results provide insight into how the heterogeneities developed during the early stages of hydration persist in the structure of C-S-H and impact the mechanical performance of the hardened cement paste. Unraveling such links in cement hydrates can be groundbreaking and controlling them can be the key to smarter mix designs of cementitious materials. PMID:26858450

  15. LEAD AND ZINC LEACHING IN SOIL TREATED WITH IRON SMELTING RESIDUES LIXIVIAÇÃO DE CHUMBO E ZINCO EM SOLO TRATADO COM RESÍDUOS DE SIDERURGIA

    Directory of Open Access Journals (Sweden)

    Leônidas Paixão Passos

    2010-10-01

    Full Text Available

    In order to evaluate the dynamics of Zn and Pb in the soil, a greenhouse experiment was set up in pots filled with soil samples (Typic Hapludox treated with increasing doses of iron smelting residues. It was set under a completely randomized design, in a 3×5 factorial scheme, with three replications, combining three iron smelting residues (mill scale, filter press mud, and phosphate mud, with five doses for each residue (0 t ha-1, 1 t ha-1, 2 t ha-1, 4 t ha-1, and 8 t ha-1. Elephant grass was cultivated during 120 days, followed by common beans, for 75 days. In that period, contents of Zn and Pb were determined in the leachate. No Pb was found in the leachate, but Zn proved to be quite mobile in this soil. In soils treated with mill scale and filter press mud, no risk of groundwater contamination was observed, however, the 8 t ha-1 phosphate mud rate increased Zn contents in the leachate above the maximum allowed by environmental regulations. This fact limits the use of such residue for agricultural purposes. The other two residues should be evaluated in field-scale tests aiming their agricultural use.

    KEY-WORDS: Industrial residue; heavy metal; mill scale; filter press mud; phosphate mud.

  16. Treatment of a Vertical Root Fracture Using Dual-Curing Resin Cement: A Case Report

    Directory of Open Access Journals (Sweden)

    Nima Moradi Majd

    2012-01-01

    Full Text Available Introduction. Vertical root fracture (VRF is one of the most frustrating complications of root canal treatment. The prognosis of the root with VRF is poor therefore tooth extraction and root amputation are usually the only treatment options. However, bonding of the fracture line with adhesive resin cement during the intentional replantation procedure was recently suggested as an alternative to tooth extraction. Methods. A vertically fractured left maxillary incisor was carefully extracted, fracture line was treated with adhesive resin cement, a retrograde cavity was produced and filled with calcium-enriched mixture (CEM cement, and tooth was replanted. Results. After 12 months the tooth was asymptomatic. The size of periapical radiolucency was noticeably reduced and there was no clinical sign of ankylosis. Conclusion. Using adhesive resin cement to bond the fracture lines extraorally in roots with VRF and intentional replantation of the reconstructed teeth could be considered as an alternative to tooth extraction, especially for anterior teeth.

  17. Performance study and influence of radiation emission energy and soil contamination level on γ-radiation shielding of stabilised/solidified radionuclide-polluted soils

    International Nuclear Information System (INIS)

    This work focuses on the stabilisation/solidification (S/S) of radionuclide-polluted soils at different 232Th levels using Portland cement alone and with barite aggregates. The potential of S/S was assessed applying a full testing protocol and calculating γ-radiation shielding (γRS) index, that included the measurement of soil radioactivity before and after the S/S as a function of the emission energy and soil contamination level. The results indicate that setting processes are strongly dependent on the contaminant concentration, and for contamination level higher than 5%, setting time values longer than 72 h. The addition of barite aggregates to the cement gout leads to a slight improvement of the S/S performance in terms of durability and contaminant leaching but reduces the mechanical resistance of the treated soils samples. Barite addition also causes an increase in the γ-rays shielding properties of the S/S treatment up to about 20%. Gamma-ray measurements show that γRS strongly depends on the energy, and that the radioactivity with the contamination level was governed by a linear trend, while, γRS index does not depend on the radionuclide concentration. Results allow the calculated γRS values and those available from other experiments to be applied to hazard radioactive soil contaminations. - Highlights: • We assess the effects of 232Th contamination on performance of S/S treated soil. • We assess the γ-radiation shielding of the S/S materials as a function of energy. • We report a full testing protocol for assessing S/S resistance performance. • Emission energy influences the γ radiation shielding of the S/S. • Barite gives high γ-radiation shielding and low contaminant leaching

  18. Bone-Cement: The New Medical Quick Fix

    Directory of Open Access Journals (Sweden)

    Dinesh Bhatia

    2010-01-01

    Full Text Available

    Bone Cement is being widely used in vertebroplasty, a minimally invasive surgical procedure to treat spinal fractures and collapsed vertebrae. It is being labeled as a concrete success in medical field. It is being used to treat fractures due to osteoporosis, menopause, steroids, hyperthyroidism and chronic obstructive pulmonary diseases.  In this technique a needle with bone cement (PMMA, polymethylmethacrylate is injected into the collapsed vertebra after administering local anesthesia to patient. It solidifies within few minutes and provides support to damaged bone resulting in relief to the patient. It also prevents the movement between different parts of the broken bone. Hence it requires a short hospital stay for the patient and the procedure can be performed with much ease and at significant lower costs. Patient can resume normal activity within a day or so. Bone cement is now being referred to as the quick medical fix material for early repair of fractures.

  19. The cement recycling of the earthquake disaster debris by Hachinohe Cement Co., Ltd

    International Nuclear Information System (INIS)

    A tremendous quantity of earthquake disaster debris and tsunami sediment was resulted by the Great East Japan Earthquake on March 11, 2011. Hachinohe Cement Co., Ltd., a Sumitomo Osaka Cement subsidiary, was the first cement industry company to receive and process such waste materials outside of their usual prefecture area, while the company is performing their treatment and recycling services locally in Hachinohe City and Aomori Prefecture. This report provides an explanation about the recycling mechanism of waste materials and by-products in cement manufacturing process, and introduces an example of actual achievements for the disaster debris treatment by utilizing the cement recycling technologies at the Hachinohe Cement Plant. (author)

  20. Effect of Industrial By-Products on Unconfined Compressive Strength of Solidified Organic Marine Clayey Soils

    Directory of Open Access Journals (Sweden)

    Chan-Gi Park

    2015-08-01

    Full Text Available The use of industrial by-products as admixture to ASTM Type I cement (ordinary Portland cement (OPC was investigated with the objective of improving the solidification of organic marine clayey soils. The industrial by-products considered in this paper were oyster-shell powder (OSP, steelmaking slag dust (SMS and fuel-gas-desulfurized (FGD gypsum. The industrial by-products were added to OPC at a ratio of 5% based on dry weight to produce a mixture used to solidify organic marine clayey soils. The dosage ratios of mixtures to organic marine clayey soils were 5, 10 and 15% on a dry weight basis. Unconfined compressive strength (UCS test after 28 days revealed that the highest strength was obtained with the OPC + SMS 15% mixing ratio. The UCS of specimens treated with this mixture was >500 kPa, compared with 300 kPa for specimens treated with a 15% OPC + OSP mixture and 200 kPa when 15% of OPC was used alone. These results were attributed to the more active hydration and pozzolanic reaction of the OPC + SMS mixture. This hypothesis was verified through X-ray diffraction (XRD and scanning electron microscopy (SEM analyses, and was confirmed by variations in the calcium carbonate (CaCO3 content of the materials during curing.

  1. Influence of Geosta Addition on Cement-stabilised Chicoco Mud of the Niger Delta

    Directory of Open Access Journals (Sweden)

    Olujide Omotosho

    2005-01-01

    Full Text Available Chicoco is a very soft and extremely compressible organic marine mud found extensively and to considerable depths within the saline tidal flat or mangrove swamp of the Niger delta in southern Nigeria. Natural chicoco is highly undesirable, barely able to support a human of average weight but air-dried chicoco has been used successfully by the indigeneous people for shore protection, etc. especially if placed above water. Plain cement stabilization of most organic soils (including chicoco is known to be ineffective. In this study, geosta, a chemical stabiliser relatively newly developed for organic soils was combined with ordinary Portland cement to stabilise chicoco. It was observed that neutralisation of acidic "air-dried" chicoco by basic geosta inhibited the expected ion-exchange reaction and its attendant improvement on mechanical properties. As a result and as geosta content increases, maximum dry density (MDD was found to be only marginally improved but better for higher cement contents while optimum moisture content (OMC decreases but with higher values for lower cement contents. Unsoaked CBR (but with samples wax-cured for 3 days on the other hand was found to maximise at low geosta content and thereafter decreases continually - a major cost advantage in earthworks. In fact, the most effective influence was obtained at 4.0% cement plus about 1.5% geosta. This stabilization was also found to produce optimum road sub-base materials.

  2. Penetrability due to filtration tendency of cement based grouts

    OpenAIRE

    Eklund, Daniel

    2005-01-01

    Grouting as a method of strengthening and sealing rock, soil and concrete is widely used. The possibilities of sealing structures are of great importance from both an economical and environmental point of view. The cost of grouting has in certain projects been as high as the cost for the blasting and excavation of the tunnel. To improve the technique of grouting with cement based material, it is necessary to focus on the properties of the used grout mixture. The ability of a grout to penetrat...

  3. WHITE CEMENT IN SUSTAINABLE DEVELOPMENT

    OpenAIRE

    Y.C.P RAMANA BABU; B.SAI DOONDI; N. M .V .VAMSI KRISHNA; K.Prasanthi

    2013-01-01

    India is one among the fast developing countries in the world in the areas of Infrastructure. Now a day, Carbon monoxide (CO) and carbon dioxide (CO2) are the temporary atmospheric pollutants in the environment chiefly emitted from the fuel burning vehicles and street lights which lead to global warming and pose a major threat tothe survival and sustainable development. This paper deals with the principal purpose of use of white cement in pavement design which will take care of the Green hous...

  4. ROTARY SCREW SYSTEMS IN CEMENT

    OpenAIRE

    Taratuta V. D.; Belokur K. A.; Serga G. V.

    2016-01-01

    The article presents results of research of rotary-screw systems in relation to the creation of rotary kilns for the annealing of-cuttings in the preparation of cement clinker. Using the proposed design, in comparison with known designs of similar purpose, it significantly improves performance, reduces size and power consumption through the use of rotary screw systems in the form of screw rotors and drums made hollow with sidewalls assembled from separate strips or plates of different geometr...

  5. Calcium sulfoaluminate cement blended with OPC: A potential binder to encapsulate low-level radioactive slurries of complex chemistry

    International Nuclear Information System (INIS)

    Investigations were carried out in order to solidify in cement a low-level radioactive waste of complex chemistry obtained by mixing two process streams, a slurry produced by ultra-filtration and an evaporator concentrate with a salinity of 600 gxL-1. Direct cementation with Portland cement (OPC) was not possible due to a very long setting time of cement resulting from borates and phosphates contained in the waste. According to a classical approach, this difficulty could be solved by pre-treating the waste to reduce adverse cement-waste interactions. A two-stage process was defined, including precipitation of phosphates and sulfates at 60 deg. C by adding calcium and barium hydroxide to the waste stream, and encapsulation with a blend of OPC and calcium aluminate cement (CAC) to convert borates into calcium quadriboroaluminate. The material obtained with a 30% waste loading complied with specifications. However, the pre-treatment step made the process complex and costly. A new alternative was then developed: the direct encapsulation of the waste with a blend of OPC and calcium sulfoaluminate cement (CSA) at room temperature. Setting inhibition was suppressed, which probably resulted from the fact that, when hydrating, CSA cement formed significant amounts of ettringite and calcium monosulfoaluminate hydrate which incorporated borates into their structure. As a consequence, the waste loading could be increased to 56% while keeping acceptable properties at the laboratory scale.

  6. WHITE CEMENT IN SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Y.C.P RAMANA BABU

    2013-04-01

    Full Text Available India is one among the fast developing countries in the world in the areas of Infrastructure. Now a day, Carbon monoxide (CO and carbon dioxide (CO2 are the temporary atmospheric pollutants in the environment chiefly emitted from the fuel burning vehicles and street lights which lead to global warming and pose a major threat tothe survival and sustainable development. This paper deals with the principal purpose of use of white cement in pavement design which will take care of the Green house gases (i.e., CO and CO2 and also saves lot of money in the long run process. A small amount of these gases in environment can cause major problems over time. Use of white cement in composite pavement design where there is heavy traffic loads are acting as well as number of vehicles are more such as junctions, bus stops, check posts etc., can perform better and acts asenvironment friendly. Its light colour reflects more than bituminous pavement so that it can be easily identified and avoid accidents to some extent. White cement helps to lower the average bus stop, junction temperature providing comfort to the people because it has high solar reflectance there by reducing “urban heat island” effect. In addition to this it has some more advantages which increase the sustainability, durability and workability of the pavements.

  7. Importance of microscopy in durability studies of solidified and stabilized contaminated soils

    Science.gov (United States)

    Klich, I.; Wilding, L.P.; Drees, L.R.; Landa, E.R.

    1999-01-01

    Solidification/stabilization (S/S) is recognized by the U.S. EPA as a best demonstrated available technology for the containment of contaminated soils and other hazardous wastes that cannot be destroyed by chemical, thermal, or biological means. Despite the increased use of S/S technologies, little research has been conducted on the weathering and degradation of solidified and stabilized wastes once the treated materials have been buried. Published data to verify the performance and durability of landfilled treated wastes over time are rare. In this preliminary study, optical and electron microscopy (scanning electron microscopy [SEM], transmission electron microscopy [TEM] and electron probe microanalyses [EPMA]) were used to evaluate weathering features associated with metal-bearing contaminated soil that had been solidified and stabilized with Portland cement and subsequently buried on site, stored outdoors aboveground, or achieved in a laboratory warehouse for up to 6 yr. Physical and chemical alteration processes identified include: freeze-thaw cracking, cracking caused by the formation of expansive minerals such as ettringite, carbonation, and the movement of metals from waste aggregates into the cement micromass. Although the extent of degradation after 6 yr is considered slight to moderate, results of this study show that the same environmental concerns that affect the durability of concrete must be considered when evaluating the durability and permanence of the solidification and stabilization of contaminated soils with cement. In addition, such evaluations cannot be based on leaching and chemical analyses alone. The use of all levels of microscopic analyses must be incorporated into studies of the long-term performance of S/S technologies.Solidification/stabilization (S/S) is recognized by the U.S. EPA as a best demonstrated available technology for the containment of contaminated soils and other hazardous wastes that cannot be destroyed by chemical

  8. Scanning electron microscopy analysis of dental cements

    Directory of Open Access Journals (Sweden)

    Radosavljević Radivoje D.

    2009-01-01

    Full Text Available The aim of this study was to compare in vitro the characteristics of different types of luting cements (zinc phosphate, glass-ionomer and resin based composite cement using scanning electron microscopy (SEM analysis and microleakage for the quality range of materials. Dental cements were mixed in accordance with the manufacturer's instructions and formed with posts in dental root canals of extracted teeth. The quality of cement was determined by SEM observation on horizontal sectioned roots with fixed posts according to specific pore and marginal gap diameter. The microleakage was measured on specimens immersed in Lofler (methylene blue solution. The mean values of the maximal diameter of pores, marginal gaps and microleakage of conventional cements are remarkably larger in comparison with composite luting agents. In conclusion, the quality and efficiency of composite luting agents in comparison with conventional cements are more successful in protecting the interior of tooth from penetration of oral fluids, bacteria and bacterial toxins into unprotected dentine.

  9. Cement replacement materials. Properties, durability, sustainability

    Energy Technology Data Exchange (ETDEWEB)

    Ramezanianpour, Ali Akbar [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Concrete Technology Center

    2014-04-01

    The aim of this book is to present the latest findings in the properties and application of Supplementary Cementing Materials and blended cements currently used in the world in concrete. Sustainability is an important issue all over the world. Carbon dioxide emission has been a serious problem in the world due to the greenhouse effect. Today many countries agreed to reduce the emission of CO2. Many phases of cement and concrete technology can affect sustainability. Cement and concrete industry is responsible for the production of 7% carbon dioxide of the total world CO2 emission. The use of supplementary cementing materials (SCM), design of concrete mixtures with optimum content of cement and enhancement of concrete durability are the main issues towards sustainability in concrete industry.

  10. Sustainable Development of the Cement Industry and Blended Cements to Meet Ecological Challenges

    OpenAIRE

    Konstantin Sobolev

    2003-01-01

    The world production of cement has greatly increased in the past 10 years. This trend is the most significant factor affecting technological development and the updating of manufacturing facilities in the cement industry. Existing technology for the production of cement clinker is ecologically damaging; it consumes much energy and natural resources and also emits pollutants. A new approach to the production of blended or high-volume mineral additive (HVMA) cement helps to improve its ecologi...

  11. Global Cement Industry: Competitive and Institutional Dimensions

    OpenAIRE

    Selim, Tarek; Salem, Ahmed

    2010-01-01

    The cement industry is a capital intensive, energy consuming, and vital industry for sustaining infrastructure of nations. The international cement market –while constituting a small share of world industry output—has been growing at an increasing rate relative to local production in recent years. Attempts to protect the environment in developed countries –especially Europe—have caused cement production plants to shift to countries with less stringent environmental regulations. Along with con...

  12. Characterization of cement composites with mineral additives

    OpenAIRE

    Korat, Lidija

    2015-01-01

    Doctoral dissertation is aimed at characterizing cement composites with mineral additives representing the industrial waste material (fly ash, granulated blast furnace slag and biomass fly ash). Their usage can replace high cement shares in individual cases and is, however, favourable due to the production costs reduction and environment burden decrease, including the decreased emission of greenhouse gases as well as lower energy use. Cement composites (in fresh or hardened state)...

  13. Premixed calcium silicate cement for endodontic applications

    OpenAIRE

    Persson, Cecilia; Engqvist, Håkan

    2011-01-01

    Calcium silicate-based materials (also called MTA) are increasingly being used in endodontic applications. However, the handling properties of MTA are not optimal when it comes to injectability and cohesion. Premixing the cements using glycerol avoids these issues. However, there is a lack of data on the effect of common cement variables on important properties of premixed cements for endodontic applications. In this study, the effects of liquid-to-powder ratio, amount of radiopacifier and am...

  14. Water dynamics in glass ionomer cements

    Science.gov (United States)

    Berg, M. C.; Jacobsen, J.; Momsen, N. C. R.; Benetti, A. R.; Telling, M. T. F.; Seydel, T.; Bordallo, H. N.

    2016-07-01

    Glass ionomer cements (GIC) are an alternative for preventive dentistry. However, these dental cements are complex systems where important motions related to the different states of the hydrogen atoms evolve in a confined porous structure. In this paper, we studied the water dynamics of two different liquids used to prepare either conventional or resin-modified glass ionomer cement. By combining thermal analysis with neutron scattering data we were able to relate the water structure in the liquids to the materials properties.

  15. Total hip arthroplasty in patients with avascular necrosis of the hip. Follow-up observations on cementless and cemented operations.

    Science.gov (United States)

    Katz, R L; Bourne, R B; Rorabeck, C H; McGee, H

    1992-08-01

    Thirty-one patients with avascular necrosis of the hip were treated by 34 total hip arthroplasties (THAs). All patients were observed prospectively with a minimum two-year follow-up evaluation (average, 46 months; range, 24-84 months). Twenty had cemented arthroplasties using contemporary cementing techniques. This included insertion of a medullary plug, cleansing of the canal with a medullary brush, pulsatile lavage irrigation, and insertion of the cement with a cement gun. In 14 hips, a cementless prosthesis was used. Patients were rated using a modified Harris hip score. Sequential postoperative roentgenograms were analyzed in each patient. The overall Harris hip score ratings were 88 in the cemented and 84 in the noncemented groups. Mechanical failure with loosening of the femoral component occurred in one patient who developed deep sepsis. Significant thigh pain occurred in four patients in the noncemented group. Previous studies in the literature have generally reported unfavorable results in patients with avascular necrosis of the hip treated with THA. Using cementless and cemented fixation with contemporary cementing techniques, improved results can be expected. A high incidence of thigh pain (29%) in the cementless group remains a problem. PMID:1499201

  16. Strength and Stiffness Development in Soft Soils: A FESEM aided Soil Microstructure Viewpoint

    Science.gov (United States)

    Wijeyesekera, D. C.; Ho, M. H.; Bai, X.; Bakar, I.

    2016-07-01

    This paper opens with an overview of the debatable definition of soft soil that goes beyond a (CH) organic / inorganic clay and OH peat to include weakly cemented periglacial deposits of loess and alike. It then outlines the findings obtained from stiffness test on cement-stabilised soft clay. The findings are complemented with a microstructure viewpoint obtained using field emission scanning electron microscope (FESEM). Research also comprised of making cylindrical stabilised clay samples, prepared in the laboratory with various rubber chips contents and cement, and then aged for 28 days. The samples were then subjected to unconfined compressive strength (UCS) test and observations were also made of its microstructure using the FESEM. The impact of the soil microstructure on the stiffness result was studied both with the stabilized soil and also of some of the natural undisturbed loess soils. Sustainability aspect and the potential of the use of rubber chips and sand as additives to cement stabilisation are also discussed. The overall test results indicated that rubber chips and sand contributed to the improvement in unconfined compressive strength (qu). The derogatory influence of moisture on the stiffness of the stabilised clay was studied simultaneously. SEM micrographs are presented that show bonding of cement, rubber chips/ sand and soft clay, granular units and aggregated / agglomerated units in loess. The paper concludes with observations on the dependence of soil microstructure on the soil strength and deformability and even collapsibility of the loess. Current practices adopted as engineering solutions to these challenging soils are outlined.

  17. Retention of Root Canal Posts: Effect of Cement Film Thickness, Luting Cement, and Post Pretreatment.

    Science.gov (United States)

    Sahafi, A; Benetti, A R; Flury, S; Peutzfeldt, A

    2015-01-01

    The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc] and a self-etch adhesive resin cement [Panavia F2.0]) were used. After removal of the crowns of 360 extracted premolars, canines, or incisors, the root canals were prepared with a parallel-sided drill system to three different final diameters. Half the posts did not receive any pretreatment. The other half received tribochemical silicate coating according to the manufacturer's instructions. Posts were then luted in the prepared root canals (n=30 per group). Following water storage at 37°C for seven days, retention of the posts was determined by the pull-out method. Irrespective of the luting cement, pretreatment with tribochemical silicate coating significantly increased retention of the posts. Increased cement film thickness resulted in decreased retention of untreated posts and of pretreated posts luted with zinc phosphate cement. Increased cement film thickness had no influence on retention of pretreated posts luted with resin cement. Thus, retention of the posts was influenced by the type of luting cement, by the cement film thickness, and by the post pretreatment. PMID:25764045

  18. The mechanical effects of different levels of cement penetration at the cement-bone interface.

    NARCIS (Netherlands)

    Waanders, D.; Janssen, D.; Mann, K.A.; Verdonschot, N.J.J.

    2010-01-01

    The mechanical effects of varying the depth of cement penetration in the cement-bone interface were investigated using finite element analysis (FEA) and validated using companion experimental data. Two FEA models of the cement-bone interface were created from micro-computed tomography data and the p

  19. The influence of ultrasound on removal of prefabricated metal post cemented with different resin cements

    Directory of Open Access Journals (Sweden)

    Atiyeh Feiz

    2013-01-01

    Conclusion: Ultrasonic energy did not decrease the retention of posts cemented with Panavia or Maxcem Elite cements. Furthermore, it seems that there is no significant difference between removal force of self-etch (Panavia and the self-etch self-adhesive (Maxcem Elite resin cements.

  20. Case Study of the California Cement Industry

    OpenAIRE

    Coito, Fred; Powell, Frank; Worrell, Ernst; Price, Lynn; Friedmann, Rafael

    2005-01-01

    California is the largest cement producing state in the U.S., accounting for between 10 percent and 15 percent of U.S. cement production and cement industry employment. The cement industry in California consists of 31 sites that consume large amounts of energy, annually: 1,600 GWh of electricity, 22 million therms of natural gas, 2.3 million tons of coal, 0.25 tons of coke, and smaller amounts of waste materials, including tires. The case study summarized in this paper focused on providi...

  1. Shrinkage Properties of Cement Stabilized Gravel

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard

    2014-01-01

    Cement stabilized gravel is an attractive material in road construction because its strength prop-erties are accommodating the increasingly higher requirements to the bearing capacity of a base course. However, reflection cracking of cement stabilized gravel is a major concern. In this pa......-per the shrinkage properties of cement stabilized gravel have been documented under various temperature and relative humidity conditions. Two cement contents corresponding to a 28-days compressive strength of 6.2 MPa and 12.3 MPa have been tested and compared. It is found that the coefficient of linear expansion...

  2. Immobilisation of radwaste in cement based matrices

    International Nuclear Information System (INIS)

    The solubilities and influence on cement pH are reported for calcium aluminate and aluminosulphate hydrates. The solubility of Ca(OH)2 is reported to 700 bars. Polymerization of C-S-H is investigated by NMR. Specific interactions of U6+ and iodine (I-, IO3-) with cement components are described. The impact of radiation on cements and the influence of higher temperature are documented. The role of dissolved Ca and CO2 in groundwaters as dissolution media for cements are reported. (author)

  3. Soils, Environment and Human Action. Challenges and Treats to an Essential Resources; Suelos, medio ambiente y accion antropica. Retos y amenzas para un recurso esencial

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Alvarez, A.; Millan, R.; Schmid, T.; Diaz Puente, J. F.

    2007-07-01

    The soil consists of a self-organized system in space and time representing an interface formed between lithosphere, hydrosphere, atmosphere and biosphere. This system includes a great structural and functional complexity due to the wide diversity of its abiotic and biotic components and to processes that occur within the system. At the same time, the soil is an irreplaceable and a non-renewable resource enabling the production of basic nourishment, fibres and other essential products for the survival of humankind. However, in the last fifty year human have contributed to an un precedent increase in erosion processes as ell as new forms of soil degradation. these include contamination, compaction or sealing of soils as a result of urban and infrastructure development. As a consequence, there is a general state of environmental degradation, induced by human intervention, that is increasing wide the exploitation of natural resources. (Author)

  4. Percutaneous Extraction of Cement Leakage After Vertebroplasty Under CT and Fluoroscopy Guidance: A New Technique

    Energy Technology Data Exchange (ETDEWEB)

    Amoretti, Nicolas, E-mail: amorettinicolas@yahoo.fr; Huwart, Laurent, E-mail: huwart.laurent@wanadoo.fr [Centre Hospitalo-Universitaire de Nice, Department of Radiology (France)

    2012-12-15

    Purpose: We report a new minimally invasive technique of extraction of cement leakage following percutaneous vertebroplasty in adults. Methods: Seven adult patients (five women, two men; mean age: 81 years) treated for vertebral compression fractures by percutaneous vertebroplasty had cement leakage into perivertebral soft tissues along the needle route. Immediately after vertebroplasty, the procedure of extraction was performed under computed tomography (CT) and fluoroscopy guidance: a Chiba needle was first inserted using the same route as the vertebroplasty until contact was obtained with the cement fragment. This needle was then used as a guide for an 11-gauge Trocar t'am (Thiebaud, France). After needle withdrawal, a 13-gauge endoscopy clamp was inserted through the cannula to extract the cement fragments. The whole procedure was performed under local anesthesia. Results: In each patient, all cement fragments were withdrawn within 10 min, without complication. Conclusions: This report suggests that this CT- and fluoroscopy-guided percutaneous technique of extraction could reduce the rate of cement leakage-related complications.

  5. Acoustic evaluation of cementing quality using obliquely incident ultrasonic signals

    Institute of Scientific and Technical Information of China (English)

    Duan Wen-Xing; Qiao Wen-Xiao; Che Xiao-Hua; Xie Hui

    2014-01-01

    Ultrasonic cement bond logging is a widely used method for evaluating cementing quality. Conventional ultrasonic cement bond logging uses vertical incidence and cannot accurately evaluate lightweight cement bonding. Oblique incidence is a new technology for evaluating cement quality with improved accuracy for lightweight cements. In this study, we simulated models of acoustic impedance of cement and cementing quality using ultrasonic oblique incidence, and we obtained the relation between cementing quality, acoustic impedance of cement, and the acoustic attenuation coeffi cient of the A0-mode and S0-mode Lamb waves. Then, we simulated models of different cement thickness and we obtained the relation between cement thickness and the time difference of the arrival between the A0 and A0′ modes.

  6. Assessment of the plasma desorption time-of-flight mass spectrometry technique for pesticide adsorption and degradation on 'as-received' treated soil samples

    OpenAIRE

    Thomas, J.-P.; Nsouli, B.; Darwish, T; Fallavier, M.; Khoury, R.; Wehbé, N.

    2005-01-01

    The assessment of the plasma desorption time-of-flight mass spectrometry (PD-TOFMS) technique as a tool for direct characterization of pesticides adsorbed on agricultural soil is made for the first time in this study. Pellets of soils impregnated by solutions of three pesticides, namely norflurazon, malathion and oxyfluorfen, as well as deposits of these solutions onto aluminum surfaces, were investigated to this end. The yield values of the most characteristic peaks of the negative ion mass ...

  7. The influence of four dual-cure resin cements and surface treatment selection to bond strength of fiber post

    OpenAIRE

    Liu, Chang; Liu, Hong; Qian, Yue-Tong; Zhu, Song; Zhao, Su-Qian

    2013-01-01

    In this study, we evaluate the influence of post surface pre-treatments on the bond strength of four different cements to glass fiber posts. Eighty extracted human maxillary central incisors and canines were endodontically treated and standardized post spaces were prepared. Four post pre-treatments were tested: (i) no pre-treatment (NS, control), (ii) sandblasting (SA), (iii) silanization (SI) and (iv) sandblasting followed by silanization (SS). Per pre-treatment, four dual-cure resin cements...

  8. Design and manufacture of Portland cement Application of statistical analysis

    OpenAIRE

    Svinning, Ketil

    2011-01-01

    The purpose of the work is to enable design and manufacture of cement with emphasis on the quality and the properties of cement. Data used in the design and manufacture were collected from predictions of properties and characteristics of cement. The properties of cement were predicted from its characteristics and from the production conditions in cement kiln and mill. The cement characteristics were in some investigations predicted from the production conditions. The design was based on sensi...

  9. Effect of ultrasonic vibration time on the retention of prefabricated posts luted with two different cements

    Directory of Open Access Journals (Sweden)

    Dastnaei Peimaneh Hosseini

    2015-01-01

    Full Text Available   Background and Aims: In case of nonsurgical endodontic re-treatment or replacing a restoration, one of the best methods for removing post from the canal is using an ultrasonic vibration. The aim of this study was to evaluate the effect of ultrasonic vibration time on the retention of post luted with zinc phosphate or glass ionmer cements.   Materials and Methods: 96 sound extracted lower premolars were selected. The coronal section of specimen was removed and the roots were endodontically treated. A 9-mm post space was prepared in each specimens and a stainless steel Parapost XP was cemented into the post space. Half of the specimens were cemented with the Zinc phosphate cement and the other by g lass ionomer cement. After 7 days of storage, both groups were equally divided into 4 subgroups of 12 teeth. Control group did not receive any treatment. The other subgroups subjected to ultrasonic vibration for 4, 8 or 12 minutes. The retention of all specimens was evaluated and data were analyzed using ANOVA and Tukey tests.   Results: In control (no ultrasonic group and 4 minute ultrasonic group, the retention of posts luted with Zinc phosphate cement were not significantly differen t from those luted with g lass ionomer cement. (P=0.372. On the other hand , applying of ultrasonic vibration for 8 and 12 minutes in zinc phosphate and 12 minutes in g lass ionomer caused a significant reduction in the retention of posts (P=0.01.   Conclusion: Although, the initial retention of two cements was not different, the ultrasonic vibration had more catastrophic effect on zinc phosphate in comparison to glass ionomer.

  10. A New Type of Granular Soil Stabilizing Binder

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new type granular soil stabilizing binder was prepared.Its composition was designed in the system of slag-clinker-gypsum-activating agent.Its properties were compared with those of 425# Portland blastfurnace-slag cement.

  11. Maize growth and soil heavy metal changes after application of phyto-treated sewage sludge%污泥植物处理后对玉米生长及土壤重金属含量的影响

    Institute of Scientific and Technical Information of China (English)

    许田芬; 谢方文; 丘锦荣; 卫泽斌; 郭晓方; 吴启堂

    2012-01-01

    In order to study the effect of the application of phyto-treated sewage sludge on heavy metals in soil and maize (Zea mays) growth, experiments in plots with successive maize crops after applying the phyto-treated sludge were conducted with the monitoring of heavy metals in soil and crop. Results showed that the application of sludge to soil was still beneficial to maize during 2 years and the maize biomass with sludge was better than that of control. The treatment with mono-crop treated sludge resulted in the highest yield. Concerning the concentrations of Zn, Cd, Cu and Pb in maize, all harvests of corn and the stem and leaves of maize could be used as animal feeds during 2 years. But only the corn grains of the third harvest and there-after could be conformed to the food standards. The concentrations of heavy metals in soil declined with time, the annual disappearance rates were 32%-35% for Zn, 28%-33% for Cd, 18%-30% for Cu and 15%-23% for Pb, and the disappearance rates were higher for the sludge treated soils than that of control and the chemical fertilizer treated soils. The total concentrations of Zn and Pb in the up-soil layer treated with sludge did not show significant difference with the control after 2 years.%为了探明植物处理后污泥作为肥料施用后对后续作物和土壤的影响,将植物处理后的污泥混于土壤,种植后续作物玉米(Zea mays),测定作物产量以及土壤和作物的重金属含量.结果表明,污泥施用2a后仍有肥效,其玉米生物量显著大于无污泥的对照处理,且单种植物处理后的污泥肥效要优于无植物或套种处理的污泥.施用污泥后的2a内,4季玉米的茎叶和籽粒Zn、Cd、Cu和Pb含量均符合饲料标准;但第3季以后玉米籽粒才可作为食用.施用污泥后土壤重金属含量随时间而下降,Zn的年消失率为32%~35%,Cd为28%~33%,Cu为18%~30%,Pb为15%~23%;施用污泥的土壤重金属年下降率高于对照和化

  12. Solidification of Municipal Solid Waste Incineration Fly Ash with Cement and Its Leaching Behaviors of Heavy Metals

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The solidifying effect of cement addition on municipal solid waste incineration fly ash (MSWFA for short,collected from the gas exhaust system of MSW incinerator),the interaction of MSWFA with cement and water and the leaching of heavy metals from cement-solidified MSWFA are investigated.The main results show that:(1) when MSWFA is mixed with cement and water,H2 evolution,the formation and volume expansion of AFt will take place,the volume expansion can be reduced by ground rice husk ash addition;(2) heavy metals do leach from cement-solidified MSWFA and at lower pH more leaching will occur;(3) compared with cement-solidified fly ash,the leachate of solidified MSWFA is with higher heavy metal contents;(4) with the increment of cement addition leached heavy metals are decreased;and (5) concentrations of Zn,Mn,Cu and Cd in all the leachates can meet the relevant Standards of Japan,but as the regulations for soil and groundwater protection of Japan are concerned,precautions against the leaching of Pb,Cl- and Cr6+ and so on are needed.

  13. Antibacterial activity of selected glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Elżbieta Łuczaj-Cepowicz

    2014-01-01

    Full Text Available Introduction: The aim of the paper was to determine the antibacterial activity of four glass ionomer cements against bacteria of the genera Streptococcus and Lactobacillus. Material and methods: Four capsulated glass ionomer cements were applied in the study: Fuji Triage (GC, Fuji IX (GC, Ketac Molar (3M Espe and Ketac Silver (3M Espe. Four standard bacterial strains were used to assess the antibacterial activity of the studied cements: Streptococcus mutans, S. sanguis, S. salivarius and Lactobacillus casei. The antibacterial activity was determined by the agar diffusion method. The bacterial suspension was spread with a cotton swab on TSA plates. For each material six wells (7 mm diameter, 5 mm deep were made with a cork borer. Each well was then filled with freshly prepared cements. The results were obtained by measuring the bacterial growth inhibition zone after 1, 2, 3 and 7 days. Results: Fuji Triage cement inhibited the growth of all bacterial strains. Fuji IX cement demonstrated the most potent antibacterial activity against S. sanguis. Ketac Molar showed antibacterial activity against S. sanguis and S. salivarius, whereas Ketac Silver was efficient against S. mutans as well. Neither of th