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Sample records for cement opc mortars

  1. Impedance spectroscopy study of the effect of environmental conditions in the microstructure development of OPC and slag cement mortars

    OpenAIRE

    Ortega Álvarez, José Marcos; Sánchez Martín, Isidro; Climent, Miguel-Ángel

    2015-01-01

    In this work, the microstructure of mortars made with an ordinary Portland cement and slag cement has been studied. These mortars were exposed to four different constant temperature and relative humidity environments during a 180-day period. The microstructure has been studied using impedance spectroscopy, and mercury intrusion porosimetry as a contrast technique. The impedance spectroscopy parameters make it possible to analyze the evolution of the solid fraction formation for the studied mo...

  2. Detrimental effects of cement mortar and fly ash mortar on asthma progression.

    Science.gov (United States)

    Cho, Ara; Jang, Hong-Seok; Roh, Yoon Seok; Park, Hee Jin; Talha, A F S M; So, Seung-Young; Lim, Chae Woong; Kim, Bumseok

    2013-11-01

    Currently, concrete additive materials are used worldwide to improve properties of concrete production and to reduce the total cost of the materials used in the concrete. However, the effects of exposure to various gases emitted from mortar mixed with additive materials are poorly understood. To evaluate the pattern of gas emission from cement mortar and additives, the emission levels of gas including ammonia (NH3) and volatile organic compounds (VOCs) were measured from two different mortar types, Ordinary Portland Cement (OPC), and OPC with fly ash on various time points after manufacture. On days 1, 3, 10 and 30 after manufacture, moderate concentrations of NH3 (4, 9, 12 and 5 ppm) were measured in OPC mortar (24h, 150 mm × 150 mm × 50 mm), whereas higher concentrations of NH3 (73, 55, 20 and 5 ppm) were measured in OPC mortar with fly ash (24h, 150 mm × 150 mm × 50 mm). Furthermore, the concentration of VOCs was more than 10 ppm on 1, 3, and 10 days of age in OPC and OPC with fly ash mortars. To examine the mortars' allergic effects on the respiratory system, mice were sensitized with ovalbumin (OVA) and divided into four groups: normal, asthma control, OPC mortar and OPC mortar with fly ash. The mice were housed in corresponding group cage for 10 days with OVA challenges to induce asthma. Histopathologically, increased infiltration of lymphocytes was observed in the lung perivascular area of mice housed in OPC mortar and OPC mortar with fly ash cages compared to lungs of asthma control mice. Moreover, severe bronchial lumen obstruction and increased hypertrophy of bronchial epithelial cells (pmortar with fly ash group compared to OPC mortar or asthma control groups. Lungs of the two mortar groups generally expressed higher levels of genes related with asthma, including IL-4, eotaxin and epidermal growth factor (EGF) compared to lungs of asthma control mice. Additionally, the OPC mortar with fly ash group showed higher expression of IL-5, 13 and monocyte

  3. ALKALI-ACTIVATED CEMENT MORTARS CONTAINING RECYCLED CLAY-BASED CONSTRUCTION AND DEMOLITION WASTE

    Directory of Open Access Journals (Sweden)

    F. Puertas

    2015-09-01

    Full Text Available The use of clay-based waste as an aggregate for concrete production is an amply studied procedure. Nonetheless, research on the use of this recycled aggregate to prepare alkaline cement mortars and concretes has yet to be forthcoming. The present study aimed to determine: the behaviour of this waste as a pozzolan in OPC systems, the mechanical strength in OPC, alkali-activated slag (AAS and fly ash (AAFA mortars and the effect of partial replacement of the slag and ash themselves with ground fractions of the waste. The pozzolanic behaviour of clay-based waste was confirmed. Replacing up to 20 % of siliceous aggregate with waste aggregate in OPC mortars induced a decline in 7 day strength (around 23 wt. %. The behaviour of waste aggregate in AAMs mortars, in turn, was observed to depend on the nature of the aluminosilicate and the replacement ratio used. When 20 % of siliceous aggregate was replaced by waste aggregate in AAS mortars, the 7 day strength values remained the same (40 MPa. In AAFA mortars, waste was found to effectively replace both the fly ash and the aggregate. The highest strength for AAFA mortars was observed when they were prepared with both a 50 % replacement ratio for the ash and a 20 % ratio for the aggregate.

  4. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.;

    1999-01-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature), The measurements...

  5. The aggressiveness of pig slurry to cement mortars

    OpenAIRE

    Massana Guitart, Jordi; Guerrero Bustos, Ana; Antón Fuentes, Rebeca; Garcimartin Molina, Miguel Angel; Sanchez Espinosa, Elvira

    2013-01-01

    The aim was to measure the behaviour of various mortars employed in livestock media in central Spain and to analyse the aggressiveness of pig slurry to cement blended with fly ash mortars. To achieve this, mortar specimens were immersed in ponds storing pig slurry. Mortar specimens, of 40 ? 40 ? 160 mm, were made from four types of cement commonly used and recommended for rural areas. The types were a sulphate-resistant Portland cement and three cements blended in different proportions with ...

  6. EFFECT OF NANOMATERIALS IN CEMENT MORTAR CHARACTERISTICS

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    WAIL N. AL-RIFAIE

    2016-09-01

    Full Text Available Concrete is considered as brittle materials and widely used due to high compressive strength but unfortunately having and has low tensile strength that has a numerous negative impacts on the lifespan of concrete made structures. Therefore, mechanical properties of cement mortar have been investigated experimentally using different types and ratios of nano material to improve the properties. Since the strength of the concrete is of high importance, different materials have been used to enhance the compressive and the tensile characteristics of the cement mortar compressive and tensile strength. Mainly, this objective has been implemented through using micro cement, micro sand, nano silica, and nano clay in developing a nano-cement mortar which can to improve the concrete for the constructional applications. The samples were prepared and tested under tensile and compressive mode according to ASTM-2011 regulations for concrete. The parameters that are taken consideration during the investigation were micro sand, micro cement, nano silica, developed nano clay, and naphthalene sulphonate as super- plasticizers. In general, it has been observed that the results showed a significant increase in both compressive and tensile strength of the mortar at early stages of hardening, where a maximum increase of 22% in the compressive strength was achieved , whereas 3.7 time increase in the compressive strength was recorded over the tradition levels of the concrete strength.

  7. Characterization and modeling of major constituent equilibrium chemistry of a blended cement mortar

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    Meeussen J.C.L.

    2013-07-01

    Full Text Available Cementitious materials containing ground granulated iron blast furnace slag and coal combustion fly ash as admixtures are being used extensively for nuclear waste containment applications. Whereas the solid phases of ordinary Portland cement (OPC have been studied in great detail, the chemistry of cement, fly ash and slag blends has received relatively less study. Given that OPC is generally more reactive than slag and fly ash, the mineralogy of OPC provides a logical starting point for describing the major constituent chemistry of blended cement mortars. To this end, a blended cement mortar containing Portland cement, granulated blast furnace slag, fly ash and quartz sand was modeled using a set of solid phases known to form in hydrated OPC with the geochemical speciation solver LeachXS/ORCHESTRA. Comparison of modeling results to the experimentally determined pH-dependent batch leaching concentrations (USEPA Method 1313 indicates that major constituent concentrations are described reasonably well with the Portland cement mineral set; however, modeled and measured aluminum concentrations differ greatly. Scanning electron microscopic analysis of the mortar reveals the presence of Al-rich phyllosilicate minerals heretofore unreported in similar cementitious blends: kaolinite and potassic phyllosilicates similar in composition to illite and muscovite. Whereas the potassic phyllosilicates are present in the quartz sand aggregate, the formation of kaolinite appears to be authigenic. The inclusion of kaolinite in speciation modeling provides a substantially improved description of the release of Al and therefore, suggests that the behavior of phyllosilicate phases may be important for predicting long-term physico-chemical behavior of such systems.

  8. Influence of Temperature on Sulfate Attack of Limestone Filler Cement Mortar

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Mortar prisms were made with three different cementitious materials (with or without mineral admixture) plus 30% mass of limestone filler. After 28 days of curing in water at room temperature, the mortars were submerged in 2% magnesium sulfate solution at different temperatures (5 ℃, 20 ℃ and alternate temperature between 5 ℃ and 20 ℃) for a year. The appearance and strength development were measured on these immersed prisms at intervals, and samples selected from the surface of prisms were examined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results show that the influence of temperature on the resistance to sulfate attack of mortar is related to the binder compositions. A higher temperature leads to a quicker strength loss and appearance deterioration of the mortar without mineral admixture. For blended cements, a higher temperature is favorable for the pozzolanic reaction of mineral admixture and the overall deterioration of mortar is reduced with the increasing temperature. When the mineral admixture has a lower reactivity, such influence of temperature on the resistance to sulfate attack of mortar containing admixtures becomes greater. At the three different solution temperatures, two blended cements show significantly improved resistances to sulfate attack. After 1 year of exposure to magnesium sulfate solutions, the formation of thaumasite was checked in the OPC mortars at both 5 ℃ and 20 ℃. It is concluded that the thaumasite formation is not limited to structures at low temperature (less than 15 ℃).

  9. Influence of Pore Structure on Compressive Strength of Cement Mortar

    OpenAIRE

    Haitao Zhao; Qi Xiao; Donghui Huang; Shiping Zhang

    2014-01-01

    This paper describes an experimental investigation into the pore structure of cement mortar using mercury porosimeter. Ordinary Portland cement, manufactured sand, and natural sand were used. The porosity of the manufactured sand mortar is higher than that of natural sand at the same mix proportion; on the contrary, the probable pore size and threshold radius of manufactured sand mortar are finer. Besides, the probable pore size and threshold radius increased with increasing water to cement r...

  10. Reactivity of Ordinary Portland Cement (OPC) grout and various lithologies from the Harwell research site

    International Nuclear Information System (INIS)

    Ordinary Portland Cement (OPC) has been used in the completion of boreholes on the Harwell Research Site, AERE, Oxfordshire. The purpose of this study was to examine the effect of OPC and the alkaline pore fluids generated during its setting on the various lithological types encountered in the boreholes. To facilitate this, samples of core representing the various rock types were selected and cement-rock composites were prepared from these in the laboratory to simulate the borehole cements. After a curing period of 15 months the cores and associated cement plugs were examined for any signs of reactivity or bonding. The best cement-rock bonding was shown by naturally well-cemented sandstone and limestone lithologies. Although no significant chemical reaction was seen to have occurred between OPC and rock, the OPC appears able to bind onto the rock surface because of the rigidity of the rock surface. Therefore, the best cement rock bonding and seal with OPC may be expected in the limestones of the Great Oolite Group, Inferior Oolite Group and parts of the Corallian Beds. Because of the reactivity of OPC towards certain lithologies a better borehole seal in such a sedimentary sequence might be achieved using a bentonite backfill in those parts of the sequence which either react with or bond only weakly to OPC. (author)

  11. EQUIVALENT MODEL OF EXPANSION OF CEMENT MORTAR UNDER SULPHATE EROSION

    Institute of Scientific and Technical Information of China (English)

    Jue Zhu; Minqiang Jiaug; Jiankang Chen

    2008-01-01

    The expansion property of cement mortar under the attack of sulfate ions is studied by experimental and theoretical methods.First,cement mortars are fabricated with the ratio of water to cement of 0.4,0.6,and 0.8.Secondly,the expansion of specimen immerged in sulphate solution is measured at different times.Thirdly,a theoretical model of expansion of cement mortar under sulphate erosion is suggested by virtue of represent volume element method.In this model, the damage evolution due to the interaction between delayed ettringite and cement mortar is taken into account.Finally,the numerical calculation is performed.The numerical and experimental results indicate that the model perfectly describes the expansion of the cement mortar.

  12. Characteristics of Bamboo Leaf Ash Blended Cement Paste and Mortar

    OpenAIRE

    Umoh A.A.; Odesola I.

    2015-01-01

    The use of bamboo leaf ash as cement supplement can contribute to reduction in cost and environmental hazard associated with cement production as well as waste pollution caused by the littered bamboo leaves. Therefore, the characteristics of cement paste and mortar incorporating bamboo leaf ash were investigated. The results of the physical properties of the pastes were within the requirements stipulated by relevant standards while that of the mortar cubes indicated that the compressive stren...

  13. Early age monitoring of cement mortar using embedded piezoelectric sensors

    Science.gov (United States)

    Narayanan, Arun; Subramaniam, Kolluru V. L.

    2016-04-01

    A piezoceramic based sensor consisting of embedded Lead Zirconate Titanate (PZT) patch is developed for assessing the progression of hydration and evolution of properties of cement mortar. A method for continuous assessment of cement mortar with different water to cement ratios after casting is presented. The method relies on monitoring changes in the electromechanical (EM) conductance of a PZT patch embedded in mortar. Changes in conductance are shown to sensitively reflect the changes in the mechanical impedance of the cementitious material as it transforms from fluid to solid state.

  14. Alkaline cement mortars. Chemical resistance to sulfate and seawater attack

    OpenAIRE

    Puertas, F.; Gutiérrez, R.; Fernández-Jiménez, A.; Delvasto, S.; Maldonado, J.

    2002-01-01

    The durability and chemical resistance of alkali activated slag and fly ash/slag mortars in contact with sulfates and seawater media have been studied. Two methods were used in the evaluation of such durability: Kock-Steinegger and ASTM C1012. A mineralogical and a microstructural characterization of mortars were done at different ages of their conservation in aggressive media through XRD, SEM/ EDX and mercury porosimetry. Results showed a high durability of activated cement mortars in s...

  15. Sustainability, Eco-Point and Engineering Performance of Different Workability OPC Fly-Ash Mortar Mixes

    Directory of Open Access Journals (Sweden)

    Putri Zulaiha Razi

    2016-05-01

    Full Text Available This study investigates the engineering performance and CO2 footprint of mortar mixers by replacing Portland cement with 10%, 20%, 40% and 60% fly ash, a common industrial waste material. Samples of self-compacting mortar (SCM were prepared with four different water/binder ratios and varying dosages of superplasticizer to give three ranges of workability, i.e., normal, high and self-compacting mortar mix. The engineering performance was assessed in term of compressive strength after designated curing periods for all mixes. CO2 footprint was the environmental impact indicator of each production stage. The optimum mix obtained was at 10% replacement rate for all mixes. Total production emission reduced by 56% when the fly ash replacement rate increased from 0% to 60% (maximum. This is translated to a reduction of 80% in eco-points (assuming that the energy consumption rate of production with 0% fly ash is at 100%. Such re-utilization is encouraged since it is able to reduce possible soil toxicity due to sulfur leaching by 5% to 27% and landfill area by 15% to 91% on average.

  16. Compressive Strength Development and Microstrueture of Cement.asphalt Mortar

    Institute of Scientific and Technical Information of China (English)

    WANG Qiang; YAN Peiyu; KONG Xiangming; YANG Jinbo

    2011-01-01

    The compressive strength developing process and the microstructure of cement-asphalt mortar (CA mortar) were investigated.The fluidity of CA mortar has a great influence on its strength.The optimum value of spread diameter of slump flow test is in the range of 300 to 400 mm.The compressive strength of CA mortar keeps a relatively high growth rate in 56 days and grows slowly afterwards.The residual water of hydration in CA mortar freezes under minus environmental temperature which can lead to a significant reduction of the strength of CA mortar.Increasing A/C retards asphalt emulsion splitting and thus prolongs the setting process of CA mortar.The hydration products of cement form the major structural framework of hardened CA mortar and asphalt is a weak phase in the framework but improves the viscoelastic behavior of CA mortar.Therefore,asphalt emulsion should be used as much as possible on the condition that essential performance criterions of CA mortar are satisfied.

  17. The chemistry and expansion of limestone - Portland cement mortars exposed to sulphate containing solutions

    International Nuclear Information System (INIS)

    Some concretes in sulphate-bearing groundwaters can deteriorate slowly through chemical reactions which cause expansion and stress. The overall process involves diffusion of sulphate into the concrete, chemical reaction with some cement constituents, internal expansion and, finally, physical disruption of the reacted zone. This work addresses the chemical reactions and the expansion resulting from them so that the overall process of sulphate attack can be modelled eventually. The extent and rate of reaction of calcium sulphate with ordinary and sulphate resisting Portland cements (OPC and SRPC) have been measured under various conditions. Additionally, mortar bars were fabricated from OPC, OPC/BFS (blast furnace slag) and SRPC cements with carboniferous limestone and exposed to various sulphate-containing solutions. The linear expansion of the bars was continuously monitored over a period of about 200 days and, after exposure, the bars were analysed in detail. The results show that the bulk expansion during sulphate attack is proportional to sulphur taken up in insoluble ettringite and magnesium (when present) precipitated as brucite. The results are used to rationalise the behaviour of concretes in sulphate-bearing environments. (author)

  18. Effect of kaolin treatment temperature on mortar chloride permeability

    OpenAIRE

    Puertas, F.; Mejía de Gutiérrez, R.; J. Torres

    2007-01-01

    The present paper discusses the results of chloride resistance tests conducted on ordinary Portland cement (OPC) mortars containing a Colombian kaolin pre-treated at temperatures of from 600 to 800 ºC. The resulting metakaolin (MK) was added to OPC mortar mixes in proportions of 10 and 20% by cement weight. The mortars were compared for physical and chemical properties, including capillary absorption, chloride permeability and pore microstructure as assessed by mercury porosimetry....

  19. Influence of pore structure on compressive strength of cement mortar.

    Science.gov (United States)

    Zhao, Haitao; Xiao, Qi; Huang, Donghui; Zhang, Shiping

    2014-01-01

    This paper describes an experimental investigation into the pore structure of cement mortar using mercury porosimeter. Ordinary Portland cement, manufactured sand, and natural sand were used. The porosity of the manufactured sand mortar is higher than that of natural sand at the same mix proportion; on the contrary, the probable pore size and threshold radius of manufactured sand mortar are finer. Besides, the probable pore size and threshold radius increased with increasing water to cement ratio and sand to cement ratio. In addition, the existing models of pore size distribution of cement-based materials have been reviewed and compared with test results in this paper. Finally, the extended Bhattacharjee model was built to examine the relationship between compressive strength and pore structure.

  20. Influence of pore structure on compressive strength of cement mortar.

    Science.gov (United States)

    Zhao, Haitao; Xiao, Qi; Huang, Donghui; Zhang, Shiping

    2014-01-01

    This paper describes an experimental investigation into the pore structure of cement mortar using mercury porosimeter. Ordinary Portland cement, manufactured sand, and natural sand were used. The porosity of the manufactured sand mortar is higher than that of natural sand at the same mix proportion; on the contrary, the probable pore size and threshold radius of manufactured sand mortar are finer. Besides, the probable pore size and threshold radius increased with increasing water to cement ratio and sand to cement ratio. In addition, the existing models of pore size distribution of cement-based materials have been reviewed and compared with test results in this paper. Finally, the extended Bhattacharjee model was built to examine the relationship between compressive strength and pore structure. PMID:24757414

  1. Influence of Pore Structure on Compressive Strength of Cement Mortar

    Directory of Open Access Journals (Sweden)

    Haitao Zhao

    2014-01-01

    Full Text Available This paper describes an experimental investigation into the pore structure of cement mortar using mercury porosimeter. Ordinary Portland cement, manufactured sand, and natural sand were used. The porosity of the manufactured sand mortar is higher than that of natural sand at the same mix proportion; on the contrary, the probable pore size and threshold radius of manufactured sand mortar are finer. Besides, the probable pore size and threshold radius increased with increasing water to cement ratio and sand to cement ratio. In addition, the existing models of pore size distribution of cement-based materials have been reviewed and compared with test results in this paper. Finally, the extended Bhattacharjee model was built to examine the relationship between compressive strength and pore structure.

  2. Characteristics of Bamboo Leaf Ash Blended Cement Paste and Mortar

    Directory of Open Access Journals (Sweden)

    Umoh A.A.

    2015-01-01

    Full Text Available The use of bamboo leaf ash as cement supplement can contribute to reduction in cost and environmental hazard associated with cement production as well as waste pollution caused by the littered bamboo leaves. Therefore, the characteristics of cement paste and mortar incorporating bamboo leaf ash were investigated. The results of the physical properties of the pastes were within the requirements stipulated by relevant standards while that of the mortar cubes indicated that the compressive strength generally increased with curing age, and that the mix containing 15% Bamboo Leaf Ash (BLA by mass competes favorably with that of the reference mix at 28days and above. The water absorption and apparent porosity were observed to increase with increase in BLA content, while the bulk density decreases as the percentage of BLA increases from 5% to 25% by mass. The study concluded that 15% BLA replacing cement is adequate for the production of masonry mortar.

  3. Carbonatation Influence on Fly Ash and Portland Cement Mortars

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    P.L. Valdez–Tamez

    2009-01-01

    Full Text Available The influence of carbonation on mortars containing 25% of fly ash instead of the cementitious materials was studied. Mortar cylinder specimens were fabricated for 4 different W/C ratios: 0.35, 0.45, 0.55 and 0.65. Mortars with and without fly ash were subjected to an accelerated carbonation process. Volumetric weight, water absorption, compressive strength, water permeability, pH and mercury intrusion porosimetry of the mortar specimens were determined. Due to the fly ash pozzolanic potential, for all W/C ratios, results of the compressive strength tests at 28 days of the mortars with and without fly ash were similar. Mortars with fly ash presented similar water permeability as mortars without fly ash. PH results showed that alkalinity reduction is lower in mortars with fly ash compared to those containing cement only. In all the mortars, the porosimetric analysis indicated that porosity is reduced due to carbonation. Further more, it is showed the predominance of the macro and mesopores.

  4. Tangential adhesion strength of cement mortars in masonry

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    Derkach V.N.

    2012-05-01

    Full Text Available The initial shear strength (tangential adhesion and the angle of internal friction in the horizontal plane of mortar joints are among important characteristics, determining the masonry strength and stiffness qualities in case of share. These characteristics influence largely over the limit state approach of buildings and facilities during seismic activity and over wind, crane and other load, causing the panel frame distortion in frame buildings with masonry infill.In the paper the experimental studies results of tangential adhesion strength of cement mortars with solid and hollow ceramic bricks, porous stones, calcium silicate bricks and cellular concrete blocks are presented. This research gives experimental dependences of mortar adhesive strength with mentioned types of masonry units on compressive strength of cement mortar. There is also the comparison of the obtained results with Russian and foreign standards in this paper.

  5. POLYMER AND CEMENT MORTARS FOR THE CONSTRUCTION AND REPAIR OF BUILDINGS AND STRUCTURE

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    O. M. Pshinko

    2009-02-01

    Full Text Available In the article the analysis of polymer-cement mortars for their application in construction and repair of buildings and structures is presented. The main properties of known polymer-cement mortars used for this purpose are described. The advantages of application of polymer-cement mortars as repair materials are shown.

  6. Properties of Cement Mortar with Phosphogpysum under Steam Curing Condition

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    Kyoungju Mun

    2008-01-01

    Full Text Available The purpose of this study is to utilize waste PG as an admixture for concrete products cured by steam. For the study, waste PG was classified into 4 forms (dehydrate, β-hemihydrate, III-anhydrite, and II-anhydrite, which were calcined at various temperatures. Also, various admixtures were prepared with PG, fly-ash (FA, and granulated blast-furnace slag (BFS. The basic properties of cement mortars containing these admixtures were analyzed and examined through X-ray diffraction, scanning electron microscopy, compressive strength, and acid corrosion resistance. According to the results, cement mortars made with III-anhydrite of waste PG and BFS exhibited strength similar to that of cement mortars made with II-anhydrite. Therefore, III-anhydrite PG calcined at lower temperature can be used as a steam curing admixture for concrete second production.

  7. Effects of moisture on ultrasound propagation in cement mortar

    Science.gov (United States)

    Ju, Taeho; Li, Shuaili; Achenbach, Jan; Qu, Jianmin

    2015-03-01

    In concrete structures, moisture is often a major cause of chemically related degradations such as alkaline-silica reaction. To develop ultrasonic nondestructive evaluation techniques for monitoring such chemical degradations, it is necessary to understand how moisture affects the propagation of ultrasound in concrete. To this end, the objective of this paper is to experimentally determine the correlation between the moisture content in cement mortar and ultrasonic wave propagation. Specifically, effects of moisture on the ultrasonic phase velocity and attenuation are examined. It is found that, for the cement mortar samples considered in this study, moisture has negligible effect on the ultrasonic phase velocity. However, moisture can significantly increase the attenuation of ultrasound in cement mortar even in the sub-MHz frequency range.

  8. Use of red mud as addition for portland cement mortars

    International Nuclear Information System (INIS)

    The aim of the present research work was to investigate the possibility of adding red mud, an alkaline leaching waste that is obtained from bauxite during the Bayer process for alumina production, in the raw meal of Portland cement mortars. The red mud is classified as dangerous, according to NBR 10004/2004, and world while generation reached over 117 million tons/year. This huge production requires high consuming products to be used as incorporation matrix and we studied the influence of red mud addition on the characteristics of cement mortars and concrete. In this paper the properties of Portland cement mortars incorporating high amounts of red mud was evaluated: pH variation, fresh (setting time, workability or normal consistency and water retention), and hardened state (mechanical strength, capillary water absorption, density and apparent porosity). Results seem promising for red mud additions up to 20 wt%. (author)

  9. New methodology for assessing the environmental burden of cement mortars with partial replacement of coal bottom ash and fly ash.

    Science.gov (United States)

    Menéndez, E; Álvaro, A M; Hernández, M T; Parra, J L

    2014-01-15

    This paper assess the mechanical an environmental behaviour of cement mortars manufactured with addition of fly ash (FA) and bottom ash (BA), as partial cement replacement (10%, 25% and 35%). The environmental behaviour was studied by leaching tests, which were performed under several temperature (23 °C and 60 °C) and pH (5 and 10) conditions, and ages (1, 2, 4 and 7 days). Then, the accumulated amount of the different constituents leached was analysed. In order to obtain an environmental burden (EB) value of each cement mixture, a new methodology was developed. The EB value obtained is related to the amount leached and the hazardous level of each constituent. Finally, the integral study of compressive strength and EB values of cement mixtures allowed their classification. The results showed that mortars manufactured with ordinary Portland cement (OPC) and with coal BA had similar or even better environmental and mechanical behaviour than mortars with FA. Therefore, the partial replacement of cement by BA might be as suitable or even better as the replacement by FA.

  10. Clay content of argillites: Influence on cement based mortars

    OpenAIRE

    Habert, Guillaume; CHOUPAY, Nathalie; Escadeillas, Gilles; MONTEL, Jean Marc; Guillaume, D

    2009-01-01

    The pozzolanic activity of four heated powders containing different clays has been tested. Mineral transformations during calcination from 20 to 900 °C have been followed by X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC). Compressive strength tests were performed at 1, 7 and 28 days on cement-clay mortars using 30% of pozzolanic material as a replacement by mass for cement. Calcination temperatures corresponded to the stages of potentially high reactivity identified by XR...

  11. Adsorption of cesium on cement mortar from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Volchek, Konstantin, E-mail: konstantin.volchek@ec.gc.ca [Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario, Canada K1A 0H3 (Canada); Miah, Muhammed Yusuf [Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario, Canada K1A 0H3 (Canada); Department of Applied Chemistry and Chemical Technology, Noakhali Science and Technology University (Bangladesh); Kuang, Wenxing; DeMaleki, Zack [Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario, Canada K1A 0H3 (Canada); Tezel, F. Handan [Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis-Pasteur, Ottawa, Ontario, Canada K1N 6N5 (Canada)

    2011-10-30

    Highlights: {yields} The adsorption of cesium on cement mortar was investigated in a range of temperatures and cesium concentrations. {yields} The pseudo-second order kinetic model produced a good fit with the experimental kinetic data. {yields} Equilibrium test results correlated well with the Freundlich isotherm adsorption model. {yields} The interaction between cesium ions and cement mortar was dominated by chemical adsorption. - Abstract: The adsorption of cesium on cement mortar from aqueous solutions was studied in series of bench-scale tests. The effects of cesium concentration, temperature and contact time on process kinetics and equilibrium were evaluated. Experiments were carried out in a range of initial cesium concentrations from 0.0103 to 10.88 mg L{sup -1} and temperatures from 278 to 313 K using coupons of cement mortar immersed in the solutions. Non-radioactive cesium chloride was used as a surrogate of the radioactive {sup 137}Cs. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectroscopy. Depending on the initial cesium concentration, its equilibrium concentration in solution ranged from 0.0069 to 8.837 mg L{sup -1} while the respective surface concentration on coupons varied from 0.0395 to 22.34 {mu}g cm{sup -2}. Equilibrium test results correlated well with the Freundlich isotherm model for the entire test duration. Test results revealed that an increase in temperature resulted in an increase in adsorption rate and a decrease in equilibrium cesium surface concentration. Among several kinetic models considered, the pseudo-second order reaction model was found to be the best to describe the kinetic test results in the studied range of concentrations. The adsorption activation energy determined from Arrhenius equation was found to be approximately 55.9 kJ mol{sup -1} suggesting that chemisorption was the prevalent mechanism of interaction between cesium ions and cement mortar.

  12. Properties of Cement Mortar Produced from Mixed Waste Materials with Pozzolanic Characteristics.

    Science.gov (United States)

    Yen, Chi-Liang; Tseng, Dyi-Hwa; Wu, Yue-Ze

    2012-07-01

    Waste materials with pozzolanic characteristics, such as sewage sludge ash (SSA), coal combustion fly ash (FA), and granulated blast furnace slag (GBS), were reused as partial cement replacements for making cement mortar in this study. Experimental results revealed that with dual replacement of cement by SSA and GBS and triple replacement by SSA, FA, and GBS at 50% of total cement replacement, the compressive strength (Sc) of the blended cement mortars at 56 days was 93.7% and 92.9% of the control cement mortar, respectively. GBS had the highest strength activity index value and could produce large amounts of CaO to enhance the pozzolanic activity of SSA/FA and form calcium silicate hydrate gels to fill the capillary pores of the cement mortar. Consequently, the Sc development of cement mortar with GBS replacement was better than that without GBS, and the total pore volume of blended cement mortars with GBS/SSA replacement was less than that with FA/SSA replacement. In the cement mortar with modified SSA and GBS at 70% of total cement replacement, the Sc at 56 days was 92.4% of the control mortar. Modifying the content of calcium in SSA also increased its pozzolanic reaction. CaCl(2) accelerated the pozzolanic activity of SSA better than lime did. Moreover, blending cement mortars with GBS/SSA replacement could generate more monosulfoaluminate to fill capillary pores.

  13. Properties of Cement Mortar Produced from Mixed Waste Materials with Pozzolanic Characteristics

    Science.gov (United States)

    Yen, Chi-Liang; Tseng, Dyi-Hwa; Wu, Yue-Ze

    2012-01-01

    Abstract Waste materials with pozzolanic characteristics, such as sewage sludge ash (SSA), coal combustion fly ash (FA), and granulated blast furnace slag (GBS), were reused as partial cement replacements for making cement mortar in this study. Experimental results revealed that with dual replacement of cement by SSA and GBS and triple replacement by SSA, FA, and GBS at 50% of total cement replacement, the compressive strength (Sc) of the blended cement mortars at 56 days was 93.7% and 92.9% of the control cement mortar, respectively. GBS had the highest strength activity index value and could produce large amounts of CaO to enhance the pozzolanic activity of SSA/FA and form calcium silicate hydrate gels to fill the capillary pores of the cement mortar. Consequently, the Sc development of cement mortar with GBS replacement was better than that without GBS, and the total pore volume of blended cement mortars with GBS/SSA replacement was less than that with FA/SSA replacement. In the cement mortar with modified SSA and GBS at 70% of total cement replacement, the Sc at 56 days was 92.4% of the control mortar. Modifying the content of calcium in SSA also increased its pozzolanic reaction. CaCl2 accelerated the pozzolanic activity of SSA better than lime did. Moreover, blending cement mortars with GBS/SSA replacement could generate more monosulfoaluminate to fill capillary pores. PMID:22783062

  14. INFLUENCE OF FLY ASH REPLACEMENT ON STRENGTH PROPERTIES OF CEMENT MORTAR

    OpenAIRE

    AMARNATH YERRAMALA; BHASKAR DESAI V; RAMA CHANDURDU C

    2012-01-01

    Strength properties of fly ash mortars were evaluated through laboratory investigations. OPC of 53 grade replaced with class F fly ash with 5 - 25 % in the increments of 5 %. The results shown that at early age at all fly ash replacements the strength decreased with respect to normal mortar. However, after 28 days and above themortars made with fly ash replacement up to 15% resulted higher strength than normal OPC mortar. Fly ash replacement of 20 and 25% always had lower strength than normal...

  15. Alkali Aggregate Reaction in Alkali Slag Cement Mortars

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By means of "Mortar Bar Method",the ratio of cement to aggregate was kept as a constant 1∶2.25,the water-cement ratio of the mixture was 0.40,and six prism specimens were prepared for each batch of mixing proportions with dimensions of 10×10×60mm3 at 38±2℃ and RH≥95%, the influences of content and particle size of active aggregate, sort and content of alkali component and type of slag on the expansion ratios of alkali-activated slag cement(ASC) mortars due to alkali aggregate reaction(AAR) were studied. According to atomic absorption spectrometry,the amount of free alkali was measured in ASC mortars at 90d.The results show above factors affect AAR remarkably,but no dangerous AAR will occur in ASC system when the amount of active aggregate is below 15% and the mass fraction of alkali is not more than 5% (Na2O).Alkali participated in reaction as an independent component, and some hydrates containing alkali cations were produced, free alkalis in ASC system can be reduced enormously.Moreover,slag is an effective inhibitor, the possibility of generating dangerous AAR in ASC system is much lower at same conditions than that in ordinary Portland cement system.

  16. Considerations about the use of lime-cement mortars for render conservation purposes

    OpenAIRE

    Torgal, Fernando Pacheco; Faria, Joana; Shasavandi, Arman; Jalali, Said

    2011-01-01

    Some investigations about conservation renders points out that Portland cement based mortars should be avoided and should be replaced by lime-pozzolan mortars. However, this type of mortar is still under investigation and the majority of Portuguese construction enterprises operating in the field of building conservation do not possess enough know-how about them. Besides the absolute rejection of the use of Portland cement based mortars even with just a minimum amount appears to be a dogmat...

  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. Mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions

    Institute of Scientific and Technical Information of China (English)

    熊良宵; 虞利军

    2015-01-01

    To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation, and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the 420th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.

  19. Recycling of copper tailings as an additive in cement mortars

    OpenAIRE

    Onuaguluchi, Obinna; EREN, Özgür

    2012-01-01

    Increasing demands for copper and copper allied products have made the processing of low grade ores with high volume waste output unavoidable. Presently, billions of tons of copper tailings can be found in major copper producing countries. The impact of copper tailings at 0%, 5% and 10% addition level by mass of cement on the fresh and hardened properties of mortars were determined. Results showed that dry copper tailings affect mixture consistency negatively. However, the use of pre-wetted t...

  20. Adsorption of cesium on cement mortar from aqueous solutions.

    Science.gov (United States)

    Volchek, Konstantin; Miah, Muhammed Yusuf; Kuang, Wenxing; DeMaleki, Zack; Tezel, F Handan

    2011-10-30

    The adsorption of cesium on cement mortar from aqueous solutions was studied in series of bench-scale tests. The effects of cesium concentration, temperature and contact time on process kinetics and equilibrium were evaluated. Experiments were carried out in a range of initial cesium concentrations from 0.0103 to 10.88 mg L(-1) and temperatures from 278 to 313 K using coupons of cement mortar immersed in the solutions. Non-radioactive cesium chloride was used as a surrogate of the radioactive (137)Cs. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectroscopy. Depending on the initial cesium concentration, its equilibrium concentration in solution ranged from 0.0069 to 8.837 mg L(-1) while the respective surface concentration on coupons varied from 0.0395 to 22.34 μg cm(-2). Equilibrium test results correlated well with the Freundlich isotherm model for the entire test duration. Test results revealed that an increase in temperature resulted in an increase in adsorption rate and a decrease in equilibrium cesium surface concentration. Among several kinetic models considered, the pseudo-second order reaction model was found to be the best to describe the kinetic test results in the studied range of concentrations. The adsorption activation energy determined from Arrhenius equation was found to be approximately 55.9 kJ mol(-1) suggesting that chemisorption was the prevalent mechanism of interaction between cesium ions and cement mortar.

  1. Evaluation of structural behaviour and corrosion resistant of austenitic AISI 304 and duplex AISI 2304 stainless steel reinforcements embedded in ordinary Portland cement mortars

    International Nuclear Information System (INIS)

    The mechanical and structural behaviour of two stainless steels reinforcements, with grades austenitic EN 1.4301 (AISI 304) and duplex EN 1.4362 (AISI 2304) have been studied, and compared with the conventional carbon steel B500SD rebar. The study was conducted at three levels: at rebar level, at section level and at structural element level. The different mechanical properties of stainless steel directly influence the behaviour at section level and structural element level. The study of the corrosion behaviour of the two stainless steels has been performed by electrochemical measurements, monitoring the corrosion potential and the lineal polarization resistance (LPR), of reinforcements embedded in ordinary Portland cement (OPC) mortar specimens contaminated with different amount of chloride over one year time exposure. Both stainless steels specimens embedded in OPC mortar remain in the passive state for all the chloride concentration range studied after one year exposure. (Author) 26 refs.

  2. Utilization of ground waste seashells in cement mortars for masonry and plastering.

    Science.gov (United States)

    Lertwattanaruk, Pusit; Makul, Natt; Siripattarapravat, Chalothorn

    2012-11-30

    In this research, four types of waste seashells, including short-necked clam, green mussel, oyster, and cockle, were investigated experimentally to develop a cement product for masonry and plastering. The parameters studied included water demand, setting time, compressive strength, drying shrinkage and thermal conductivity of the mortars. These properties were compared with those of a control mortar that was made of a conventional Portland cement. The main parameter of this study was the proportion of ground seashells used as cement replacement (5%, 10%, 15%, or 20% by weight). Incorporation of ground seashells resulted in reduced water demand and extended setting times of the mortars, which are advantages for rendering and plastering in hot climates. All mortars containing ground seashells yielded adequate strength, less shrinkage with drying and lower thermal conductivity compared to the conventional cement. The results indicate that ground seashells can be applied as a cement replacement in mortar mixes and may improve the workability of rendering and plastering mortar.

  3. Chemical composition influence of cement based mortars on algal biofouling

    Science.gov (United States)

    Estelle, Dalod; Alexandre, Govin; Philippe, Grosseau; Christine, Lors; René, Guyonnet; Denis, Damidot

    2013-04-01

    The main cause of building-facade biodegradation is the growth of microorganisms. This phenomenon depends on several parameters such as the geographical situation, the environmental conditions and the surface state of the substrate. Several researches have been devoted to the study of the effect of porosity and roughness on the biofouling of stones and mortars. However, none of them have addressed the influence of the mortar chemistry on the microorganism growth kinetic. The main objective of this study is to highlight the influence of the mortar chemistry in relationship with its physical properties on biological weathering. Earlier work showed a good resistance of Calcium Aluminate Cements to biodeterioration by acidogenic bacteria (Thiobacillus) and fungi (Alternaria alternata, Aspergillus Niger and Coniosporium uncinatum). In order to characterize the influence of the mortar chemistry on biofouling, two Portland cements and two alumina cements are used. Among micro-organisms able to grow, green algae are most involved in the aesthetic deterioration of facades. Indeed, they can colonize any type of media and can be a source of nutrients for other micro-organisms such as fungi. The green algae Klebsormidium flaccidum is chosen because of its representativeness. It is indeed the species the most frequently identified and isolated from samples taken on sites. The biofouling kinetic is followed on samples exposed outdoor and on samples tested in a laboratory bench which consists in spraying an algae culture on mortar specimens. The results obtained by in situ trials are compared with the results obtained on the laboratory bench. The microorganism growth kinetic is measured by image analysis. To improve the detection of algae on the surface of the cementitious samples, the raw image is converted in the YIQ color space. Y, I and Q correspond respectively to luminance, in-phase, and quadrature. On the Q channel, the areas covered by algae and the areas of clean mortar

  4. Evaluation of electric properties of cement mortars containing pozzolans

    Directory of Open Access Journals (Sweden)

    Cruz, J. M.

    2011-03-01

    Full Text Available In this paper the evolution of the microstructure of Portland cement mortar is analyzed, by using electrical impedance measurements. Cement mortars are compared without and with two pozzolanic substitutions: spent fluid catalytic cracking catalyst (FCC and metakaolin (MK. The measurement method is described and the model for analyzing the electrical impedance spectra is developed. Three electrical parameters are defined: electrical resistivity, capacitance exponent, and capacitive factor. The results show a significant increase in resistivity of the mortars with pozzolans after 7 days of curing, especially in mortars with MK. This increase is correlated with lime-fixing by the pozzolans. The capacitive properties evolve differently at early age, but reach the same values after 148 days. The electrical and mineralogical data show that the evolution of the microstructure in the mortar with MK starts before it does in the mortars with FCC and that the final microstructure becomes different.

    En este trabajo se analiza la microestructura de morteros de cemento Portland, mediante medidas de impedancia eléctrica. Se comparan morteros de cemento sin y con dos sustituciones puzolánicas: residuo de catalizador de craqueo catalítico (FCC y metacaolín (MK. Se describe el método de medida y se desarrolla el modelo de análisis de los espectros de impedancia eléctrica. Se definen tres parámetros eléctricos: resistividad eléctrica, exponente capacitivo, y factor capacitivo. Se observa un aumento importante de la resistividad de los morteros con puzolana a partir de los 7 días de curado, sobre todo en morteros con MK. Este aumento está correlacionado con la fijación de cal de las puzolanas. Las propiedades capacitivas son diferentes a edad temprana, pero se igualan a los 148 días. Los resultados eléctricos y mineralógicos muestran que la evolución microestructural comienza antes en los morteros con MK que con FCC y que la microestructura

  5. Inhibition of Cracks on the Surface of Cement Mortar Using Estabragh Fibers

    Directory of Open Access Journals (Sweden)

    Tahereh Soleimani

    2013-01-01

    Full Text Available The influence of adding Estabragh fibers into the cement composites of mortar on surface cracks and mechanical properties of mortar has been studied at various fiber proportions of 0.25%, 0.5%, and 0.75%. The mortar shrinkage was evaluated by counting the number of cracks and measuring the width of cracks on the surface of mortar specimens. Although the Estabragh fibers loss their strength in an alkali environment of cement composites, the ability of Estabragh fibers to bridge on the microcracks in the mortar matrix causes a decrease in the number of cracks and in their width on the surface of the mortar samples in comparison with the plain mortar. However, considering the mechanical properties of specimens such as bending strength and compressive strength, among all fiber proportions, only the specimens with 0.25% of Estabragh fiber performed better in all respects compared to the physical and mechanical properties of reinforced cement composite of mortar. Consequently, by adding 0.25% of Estabragh fibers to the cement mortar, a remarkable inhibition in crack generation on fiber-containing cement composite of mortar is achieved.

  6. 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.

  7. Steel corrosion resistance in model solutions and reinforced mortar containing wastes

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.

    2012-01-01

    This work reports on the corrosion resistance of steel in alkaline model solutions and in cement-based materials (mortar). The model solutions and the mortar specimens were Ordinary Portland Cement (OPC) based. Further, hereby discussed is the implementation of an eco-friendly approach of waste util

  8. Effect of surfactants on pressure-sensitivity of CNT filled cement mortar composites

    Science.gov (United States)

    Han, Baoguo; Yu, Xun

    2014-11-01

    Sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS) were used as surfactants to disperse multi-walled carbon nanotubes (MWNT) in cement mortar and fabricate pressure-sensitive carbon nanotubes filled cement mortar composites. The pressure-sensitivity of cement mortar composites with different concentrations of MWNT and different surfactants was explored under repeated loading and impulsive loading, respectively. Experimental results indicate that the response of the electrical resistance of composites with NaDDBS to external force is more stable and sensitive than that of composites with SDS. Therefore, NaDDBS has higher efficiency than SDS for the dispersion of MWNT in cement mortar, and it is an effective surfactant for fabricating MWNT filled cement mortar composites with superior pressure-sensitivity.

  9. Dynamic Properties of Fiber Reinforced Cement Mortar

    Institute of Scientific and Technical Information of China (English)

    唐志平; 徐松林; 胡晓军; 廖香丽; 蔡建

    2004-01-01

    Based on the shear wave tracing(SWT) technique proposed by Tang Z P, particle velocity gauge and the dual internal measurement for pressure and shear waves (IMPS) system are applied to investigate the responses of fiber reinforced cement subjected to impact loading. Series of experiments are conducted. The results show that there exist four critical points, A, B, C, D, in p-V Hugoniot curves. They correspond to the Hugoniot elastic limit (HEL) of the material, the critical point for shear strength limit and transition from damage state to failure state, void collapse, and solid compression, respectively. The critical point B is difficult to be aware of and never reported. However, it can be clearly disclosed with SWT method. Based on the analyses of shear strength, it can be concluded that the transversal wave, especially the unloading transversal wave, is especially important for the dynamic damage investigation of brittle materials.

  10. Reuse of sewage sludge ashes (SSA) in cement mixtures: the effect of SSA on the workability of cement mortars.

    Science.gov (United States)

    Monzó, J; Payá, J; Borrachero, M V; Girbés, I

    2003-01-01

    The influence of sewage sludge ash (SSA) on workability of cement mortars has been studied. The irregular morphology of SSA particles produced a decrease of mortar workability. A nonlinear reduction of workability in mortars containing SSA was observed, but when SSA content in mortars was increased the workability reduction was less significant. A superplasticizer is used in order to compensate the decrease of workability produced by SSA. When SSA sized fractions were used, only significant differences in workability for mortars prepared with high water volumes or with the presence of superplasticizer were observed.

  11. Effect of graphene on mechanical properties of cement mortars

    Institute of Scientific and Technical Information of China (English)

    曹明莉; 张会霞; 张聪

    2016-01-01

    Functionalized graphene nano-sheets (FGN) of 0.01%−0.05% (mass fraction) were added to produce FGN-cement composites in the form of mortars. Flow properties, mechanical properties and microstructure of the cementitious material were then investigated. The results indicate that the addition of FGN decreases the fluidity slightly and improves mechanical properties of cement-based composites significantly. The highest strength is obtained with FGN content of 0.02% where the flexural strength and compressive strength at 28 days are 12.917 MPa and 52.42 MPa, respectively. Besides, scanning electron micrographs show that FGN can regulate formation of massive compact cross-linking structures and thermo gravimetric analysis indicates that FGN can accelerate the hydration reaction to increase the function of the composite effectively.

  12. Properties and durability of metakaolin blended cements: mortar and concrete

    Directory of Open Access Journals (Sweden)

    Abbas, Rafik

    2010-12-01

    Full Text Available This article explores the effect of metakaolin, a pozzolan, on concrete performance. Compressive and splitting tensile strength were found for specimens cured for up to 360 and 90 days, respectively. Changes were recorded in the compressive strength of specimens exposed to salt (chloride and sulfatechloride solutions, and chloride penetration and binding capacity were measured. The findings were compared to the results for concrete prepared with ordinary Portland (OPC and moderate heat of hydration (Type II cement. MK was found to have a very positive effect on 28-day concrete strength, due to microstructure improvement of the hydrated cement. Replacing cement with metakaolin effectively raised concrete resistance to chloride attack. Concrete containing metakaolin proved to be substantially more durable in sulfate-chloride environment.

    En este trabajo se estudia el efecto del metacaolín sobre las prestaciones del hormigón. Las probetas curadas a 360 y 90 días se sometieron a ensayos de resistencia a compresión y de tracción indirecta respectivamente. Se hizo un seguimiento de la resistencia a la compresión de los materiales ante el ataque de sales (soluciones de cloruro y de sulfato-cloruro y, se midió la penetración de cloruros y la capacidad de los hormigones de inmovilizar estos iones. Los resultados se compararon con los obtenidos con hormigones elaborados con cemento pórtland ordinario (OPC y, con cemento de calor de hidratación moderado (tipo II. El MK resultó influir muy positivamente en la resistencia del hormigón a 28 días debido a la mejora de la microestructura del cemento hidratado. La sustitución de cemento por metacaolín aumentó la resistencia del hormigón al ataque de cloruros. El hormigón con metacaolín demostró ser más duradero en entornos de sulfato-cloruro que los hormigones elaborados con OPC o con cemento de tipo II. Los perfiles de concentración de cloruros a distintas profundidades y la

  13. Alkaline cement mortars. Chemical resistance to sulfate and seawater attack

    Directory of Open Access Journals (Sweden)

    Puertas, F.

    2002-09-01

    Full Text Available The durability and chemical resistance of alkali activated slag and fly ash/slag mortars in contact with sulfates and seawater media have been studied. Two methods were used in the evaluation of such durability: Kock-Steinegger and ASTM C1012. A mineralogical and a microstructural characterization of mortars were done at different ages of their conservation in aggressive media through XRD, SEM/ EDX and mercury porosimetry. Results showed a high durability of activated cement mortars in sulfates and seawater media. NaOH activated mortars are the most sensitive to environment attack with formation of expansive products as gypsum and ettringite, although in very low proportion.

    Se ha estudiado la estabilidad química en medios sulfáticos y de agua de mar de morteros de escorias activadas alcalinamente y morteros de mezclas de escoria y cenizas volantes activadas alcalinamente. Se han empleado dos métodos para evaluar dicha estabilidad: Kock-Steinegger y la norma ASTM C1012. Se ha realizado una caracterización mineralógica y micro estructural de los morteros (a diferentes edades de permanencia en los medios agresivos a través de DRX, SEM/EDX y porosimetría de mercurio. Los resultados obtenidos han demostrado la elevada durabilidad de todos los morteros de cementos activados estudiados frente a la agresividad de los sulfatos y del agua de mar Los morteros de escoria activada con NaOH son los más susceptibles al ataque por esos medios, conformación de productos expansivos como el yeso y la etringita, aunque en proporciones muy bajas.

  14. Superplasticized Portland cement: Production and compressive strength of mortars and concrete

    Energy Technology Data Exchange (ETDEWEB)

    Bouzoubaa, N.; Zhang, M.H.; Malhotra, V.M. [Natural Resources Canada, Ottawa, Ontario (Canada)

    1998-12-01

    This paper deals with the effect of intergrinding different percentages of a naphthalene-based superplasticizer with Portland cement clinker and gypsum on the fineness of the product, and on the water requirement and the compressive strength of the mortars made with the superplasticized cement. The properties of the fresh and hardened concrete made with the superplasticized cements were also investigated. The results showed that the intergrinding of a given amount of a naphthalene-based superplasticizer with Portland clinker and gypsum reduced the grinding time required for obtaining the same Blaine fineness as that of the control Portland cement without the superplasticizer. The water requirement of the mortars made with the superplasticized cements was similar to that of the mortars made with the control Portland cements when the same amount of the superplasticizer was added at the mortar mixer; for a given grinding time and a Blaine fineness of {approximately}4500 cm{sup 2}/g, the mortars made with the superplasticized cement had higher compressive strength than those made with the control Portland cement. For a given grinding time or Blaine fineness of cement {ge}5000 cm{sup 2}/g, the slump loss, air content stability, bleeding, autogenous temperature rise, setting times, and compressive strength of the concrete made with the superplasticized cements were generally comparable to those of the concrete made with the control Portland cements when the superplasticizer was added at the concrete mixer.

  15. Sealing of exploratory boreholes in clay reactivity of ordinary portland cement (OPC) grouts and various lithologies from the Harwell research site. Volume 1

    International Nuclear Information System (INIS)

    As part of a research programme on the disposal of radioactive wastes in clay, Ordinary Portland Cement (OPC) has been used in the completion of boreholes on the Harwell Research Site, AERE, Oxfordshire. The purpose of this study was to examine the effect of OPC and the alkaline pore fluids generated during its setting on the various lithological types encountered in the boreholes. To facilitate this, samples of core representing the various rock types were selected and cement-rock composites were prepared from these in the laboratory to simulate the borehole cements. After a curing period of 15 months the cores and associated cement plugs were examined for any signs of reactivity or bonding. The best cement-rock bonding was shown by naturally well-cemented sandstone and limestone lithologies. Although no significant chemical reaction was seen to have occurred between OPC and rock, the OPC appears able to bind onto the rock surface because of the rigidity of the rock surface. Therefore, the best cement rock bonding and seal with OPC may be expected in the limestones of the Great Oolite Group, Inferior Oolite Group and parts of the Corallian beds. Because of the reactivity of OPC towards certain lithologies a better borehole seal in such a sedimentary sequence might be achieved using a bentonite backfill in those parts of the sequence which either react with or bond only weakly to OPC

  16. Influence of relationship water/cement upon the processing of cements with pozzolana in standard mortar

    Directory of Open Access Journals (Sweden)

    Gener Rizo, M.

    2002-03-01

    Full Text Available The processing of standard mortar is completed following different methods in accordance with the country, but they exist two fundamental tendecies, the ISO and the ASTM. The cuban norm for mechanic-physic tests is based in ISO, and so they use a constant relationship water/cement in the processing of standard mortar a great problem concerning the cement users when they tested those mixed with puzzolanes, because they don't take care of the bigger water needs of those materials. In this work we present an study of the behaviour of Pozzolanic Portland cements (PP-250 elaborates with a fix and changeable relationship water/cement, obtained starting from the fluidity of the pure Portland cement. (P-350 The results obtained shows that the mechanical resistance decreased in cement mortars PP-250 realised with changeable relationship water/cement. So we recommend the adoption of an optional procedure to elaborate a quality mortar with pozzolana cements.

    La elaboración del mortero normalizado se realiza internacionalmente por diferentes métodos, pero existen dos tendencias fundamentales, la enunciada por ISO y por ASTM. La norma cubana de ensayos físico-mecánicos de cemento se basa en la norma ISO, por lo que para la elaboración del mortero normalizado se utiliza una relación agua/cemento constante. Esto ha provocado discrepancias con los usuarios del cemento, especialmente cuando se ensayan los cementos que contienen puzolanas, ya que se plantea que no se tiene en cuenta la mayor demanda de agua de estos materiales. En el presente trabajo se presenta un estudio del comportamiento de cementos Portland Puzolánicos (PP-250 elaborados con una relación agua/ cemento fija y variable, lograda a partir de la fluidez de la pasta de cemento Portland puro (P-350. Los resultados obtenidos indican que se producen disminuciones en la resistencia mecánica en los morteros de cemento PP-250 elaborados con agua/ cemento variable y recomienda la

  17. Corrosion sensor for monitoring the service condition of chloride-contaminated cement mortar.

    Science.gov (United States)

    Lu, Shuang; Ba, Heng-Jing

    2010-01-01

    A corrosion sensor for monitoring the corrosion state of cover mortar was developed. The sensor was tested in cement mortar, with and without the addition of chloride to simulate the adverse effects of chloride-contaminated environmental conditions on concrete structures. In brief, a linear polarization resistance method combined with an embeddable reference electrode was utilized to measure the polarization resistance (Rp) using built-in sensor electrodes. Subsequently, electrochemical impedance spectroscopy in the frequency range of 1 kHz to 50 kHz was used to obtain the cement mortar resistance (Rs). The results show that the polarization resistance is related to the chloride content and Rs; ln (Rp) is linearly related to the Rs values in mortar without added chloride. The relationships observed between the Rp of the steel anodes and the resistance of the surrounding cement mortar measured by the corrosion sensor confirms that Rs can indicate the corrosion state of concrete structures.

  18. Dry and wet "deposition" studies of the degradation of cement mortars

    OpenAIRE

    Martínez-Ramírez, S.; Thompson, G.E.

    1998-01-01

    The reaction of portland cement mortars with SO2 gaseous pollutant and artificial 'acid rain' solution has been examined using laboratory exposure chambers, with realistic presentation rates of pollutants. The mortar were previously carbonated to produce superficial carbonation. Two mortars with different w/c ratio and hence specific surface were prepared and exposed into the chambers. For dry deposition of SO2 pollutant gas, the important ro...

  19. Improved cement mortars by addition of carbonated fly ash from solid waste incinerators

    OpenAIRE

    López-Zaldívar, O.; Mayor-Lobo, P. L.; Fernández-Martínez, F.; Hernández-Olivares, F.

    2015-01-01

    This article presents the results of a research developing high performance cement mortars with the addition of municipal solid waste incineration fly ash (MSWIFA) stabilized as insoluble carbonates. The encapsulation of hazardous wastes in mortar matrixes has also been achieved. The ashes present high concentrations of chlorides, Zn and Pb. A stabilization process with NaHCO3 has been developed reducing 99% the content of chlorides. Developed mortars replace 10% per weight of the aggregates ...

  20. Thermal and electrical behavior of nano-modified cement mortar

    Science.gov (United States)

    Exarchos, D. A.; Dalla, P. T.; Tragazikis, I. K.; Alafogianni, P.; Barkoula, N.-M.; Paipetis, A. S.; Dassios, K. G.; Matikas, T. E.

    2014-04-01

    This research aims in characterizing modified cement mortar with carbon nanotubes (CNTs) that act as nanoreinforcements leading to the development of innovative materials possessing multi-functionality and smartness. Such multifunctional properties include enhanced mechanical behavior, electrical and thermal conductivity, and piezo-electric characteristics. The effective thermal properties of the modified nano-composites were evaluated using IR Thermography. The electrical resistivity was measured with a contact test method using a custom made apparatus and applying a known D.C. voltage. To eliminate any polarization effects the specimens were dried in an oven before testing. In this work, the thermal and electrical properties of the nano-modified materials were studied by nondestructively monitoring their structural integrity in real time using the intrinsic multi-functional properties of the material as damage sensors.

  1. Properties of Cement Mortar by Use of Hot-Melt Polyamides as Substitute for Fine Aggregate

    Directory of Open Access Journals (Sweden)

    Xiongzhou Yuan

    2015-06-01

    Full Text Available This paper presents an experimental study on use of hot-melt polyamide (HMP to prepare mortar specimens with improved crack healing and engineering properties. The role of HMP in the crack repairing of cement mortar subjected to several rounds of heat treatment was investigated. Compatibility between HMP and hydraulic cement was investigated through X-ray diffraction (XRD and Fourier transform infrared spectra (FTIR technology. Mortar specimens were prepared using standard cement mortar mixes with HMP at 1%, 3% and 5% (by volume for fine aggregate substitute. After curing for 28 days, HMP specimens were subjected to heating at temperature of 160 °C for one, two, and three days and then natural cooling down to ambient temperature. Mechanical and durability properties of the heated HMP mortars were evaluated and compared with those of the corresponding mortars without heating. The microscopic observation of the interfacial transition zone (ITZ of HMP mortar was conducted through environmental scanning electron microscopy (ESEM. Results reveal that incorporation of HMP improves the workability of the HMP/cement binder while leading to decrease in compressive strength and durability. The heated HMP mortars after exposure to heating for one, two, and three days exhibit no obvious change in compressive strength while presenting notable increase in flexural strength and durability compared with the corresponding mortars without heating. The XRD, FTIR and ESEM analyses indicate that no obvious chemical reaction occurs between HMP and hydraulic cement, and thus the self-repairing for interfacial micro-crack in HMP/cement composite system is ascribed to the physical adhesion of HMP to cement matrix rather than the chemical bonding between them.

  2. Influence of Superplasticizers on Strength and Shrinkage Cracking of Cement Mortar under Drying Conditions

    Institute of Scientific and Technical Information of China (English)

    MA Baoguo; WANG Xin'gang; LI Xiangguo; YANG Lei

    2007-01-01

    The effects of polynaphthalene series superplasticizers(PNS) with a low content of sodium sulfate (H-UNF),with a high content of sodium sulfate(C-UNF) and polycarboxylate type superplasticizer (PC) on strength and shrinkage cracking of cement mortar under drying conditions were investigated by means of multi-channel ellipse ring shrinkage cracking test, free shrinkage and strength test. The general effect of PNS and PC is to increase the initial cracking time of mortars, and decrease the cracking sensitivity of mortars. As for decreasing the cracking sensitivity of mortars, PC>H-UNF>C-UNF. To incorporate superplasticizers is apparently to increase the free shrinkage of mortars when keeping the constant w/b ratio and the content of cement pastes. As for the effect of controlling the volume stability of mortars, PC>C-UNF>H-UNF. Maximum crack width of mortars containing PC is lower, but the development rate of maximum crack width of mortars containing H-UNF is faster in comparison with control mortars. The flexural and compressive strengths of mortars at 28-day increase with increasing superplasticizer dosages under drying conditions. PC was superior to PNS in the aspect of increasing strength.

  3. Studies on the reuse of waste printed circuit board as an additive for cement mortar.

    Science.gov (United States)

    Ban, Bong-Chan; Song, Jong-Yoon; Lim, Joong-Yeon; Wang, Soo-Kyoon; An, Kwang-Guk; Kim, Dong-Su

    2005-01-01

    The recent development in electronic industries has generated a drastic increase in production of printed circuit boards (PCB). Accordingly, the amount of waste PCB from electronic productions and waste electronics and its environmental impact such as soil and groundwater contamination have become a great concern. This study aims to propose a method for reuse of waste PCB as an additive for cement mortar. Although the expansibility of waste PCB powder finer than 0.08 mm in water was observed to be greater than 2.0%, the maximum expansion rates in water for 0.08 to approximately 0.15 and 0.15 to approximately 0.30 mm sized PCB powders were less than 2.0%, which satisfied the necessary condition as an alternative additive for cement mortar in place of sand. The difference in the compressive strength of standard mortar and waste PCB added mortar was observed to be less than 10% and their difference was expected to be smaller after prolonged aging. The durability of waste PCB added cement mortar was also examined through dry/wet conditioning cyclic tests and acidic/alkaline conditioning tests. From the tests, both weight and compressive strength of cement mortar were observed to be recovered with aging. The leaching test for heavy metals from waste PCB added mortar showed that no heavy metal ions such as copper, lead, or cadmium were detected in the leachate, which resulted from fixation effect of the cement hydrates.

  4. Determination of Chlorinated Solvent Sorption by Porous Material—Application to Trichloroethene Vapor on Cement Mortar

    OpenAIRE

    Musielak, Marion; Brusseau, Mark L.; Marcoux, Manuel; Morrison, Candice; Quintard, Michel

    2014-01-01

    Experiments have been performed to investigate the sorption of trichloroethene (TCE) vapor by concrete material or, more specifically, the cement mortar component. Gas-flow experiments were conducted using columns packed with small pieces of cement mortar obtained from the grinding of typical concrete material. Transport and retardation of TCE at high vapor concentrations (500 mg L−1) was compared to that of a non-reactive gas tracer (Sulfur Hexafluoride, SF6). The results show a large magnit...

  5. Comparing the Environmental Impacts of Alkali Activated Mortar and Traditional Portland Cement Mortar using Life Cycle Assessment

    Science.gov (United States)

    Matheu, P. S.; Ellis, K.; Varela, B.

    2015-11-01

    Since the year 1908 there has been research into the use alkali activated materials (AAM) in order to develop cementitious materials with similar properties to Ordinary Portland Cement. AAMs are considered green materials since their production and synthesis is not energy intensive. Even though AAMs have a high compressive strength, the average cost of production among other issues limits its feasibility. Previous research by the authors yielded a low cost AAM that uses mine tailings, wollastonite and ground granulated blast furnace slag (GGBFS). This mortar has an average compressive strength of 50MPa after 28 days of curing. In this paper the software SimaPro was used to create a product base cradle to gate Life Cycle Assessment (LCA). This compared the environmental impact of the AAM mortar to an Ordinary Portland Cement mortar (PCHM) with similar compressive strength. The main motivation for this research is the environmental impact of producing Ordinary Portland Cement as compared to alkali activated slag materials. The results of this LCA show that the Alkali Activated Material has a lower environmental impact than traditional Portland cement hydraulic mortar, in 10 out of 12 categories including Global Warming Potential, Ecotoxicity, and Smog. Areas of improvement and possible future work were also discovered with this analysis.

  6. Use of waste brick as a partial replacement of cement in mortar.

    Science.gov (United States)

    Naceri, Abdelghani; Hamina, Makhloufi Chikouche

    2009-08-01

    The aim of this study is to investigate the use of waste brick as a partial replacement for cement in the production of cement mortar. Clinker was replaced by waste brick in different proportions (0%, 5%, 10%, 15% and 20%) by weight for cement. The physico-chemical properties of cement at anhydrous state and the hydrated state, thus the mechanical strengths (flexural and compressive strengths after 7, 28 and 90 days) for the mortar were studied. The microstructure of the mortar was investigated using scanning electron microscopy (SEM), the mineralogical composition (mineral phases) of the artificial pozzolan was investigated by the X-ray diffraction (XRD) and the particle size distributions was obtained from laser granulometry (LG) of cements powders used in this study. The results obtained show that the addition of artificial pozzolan improves the grinding time and setting times of the cement, thus the mechanical characteristics of mortar. A substitution of cement by 10% of waste brick increased mechanical strengths of mortar. The results of the investigation confirmed the potential use of this waste material to produce pozzolanic cement.

  7. Reuse of de-inking sludge from wastepaper recycling in cement mortar products.

    Science.gov (United States)

    Yan, Shiqin; Sagoe-Crentsil, Kwesi; Shapiro, Gretta

    2011-08-01

    This paper presents results of an investigation into the use of de-inking sludge from a paper recycling mill as feedstock material in the manufacture of cement mortar products, including masonry blocks and mortar renders. Both physical and mechanical properties of mortar specimens containing various amounts of de-inking sludge were investigated. It was observed that the addition of de-inking sludge to cement mortar at a fixed water-to-cement ratio significantly reduced flow properties and increased setting time. Water absorption and volume of permeable voids of cement mortar increased with increased dosage of de-inking sludge, with a corresponding reduction of bulk density. The 91-day compressive strength of mortar samples with 2.5 wt% and 20 wt% de-inking sludge loadings retained 83% and 62% respectively of the reference mortar strength. The corresponding drying shrinkage increased by up to 160% compared to reference samples. However, a de-inking sludge loading of up to 2.5 wt% did not significantly alter measured physical and mechanical properties. The results demonstrate that despite the high moisture absorbance of de-inking sludge due to its organic matter and residual cellulose fibre content, it serves as a potential supplementary additive and its cellulosic content proving to be an active set retardant to cementitious masonry products.

  8. Mechanism and Durability of Repair Systems in Polymer-Modified Cement Mortars

    Directory of Open Access Journals (Sweden)

    Ru Wang

    2015-01-01

    Full Text Available This paper investigated the mechanism and durability of repair systems made of ordinary cement-based repair mortar and three kinds of polymer-modified repair mortars with old concrete, SBR dispersion, SAE dispersion, and SAE powder. By comparing the bonding properties of mortars before and after erosion, it was found that polymers could effectively improve the durability of the repair system and SAE powder had the best improvement. Micromorphology study of the repair mortar and the interface of repair mortar with old concrete through SEM showed that the polymer film formed from SAE powder whatever in the mortar or at the interface was dense and tough, the film formed from SAE dispersion was loose and weak, while the film formed from SBR dispersion was in between them, which explained the difference in the tensile bond strength and the durability of the repair systems.

  9. Effects of Carbon Nanotubes on Mechanical and 2D-3D Microstructure Properties of Cement Mortar

    Institute of Scientific and Technical Information of China (English)

    LIU Qiaoling; SUN Wei; JIANG Hao; WANG Caihui

    2014-01-01

    To study the influence of multi-wall carbon nanotubes (MWCNTs) on the mechanical and microstructural properties of cementitious composites, 0.00, 0.02, 0.08, 0.10, and 0.20 wt% of multi-wall carbon nanotubes were added into cement mortar, in which the cement-sand ratio was 1:1.5. The flexural and compressive strengths of cement mortar at the age of 3, 7, 28 and 90 d and the fracture performance at the age of 28 d were determined, its 2D micrograph was tested by means of SEM, and the 3D defects distribution was firstly determined with or without CNTs by means of XCT (X-ray computerized tomography). The results showed that 0.08 wt% of CNTs improved the compressive strength and flexural strength by 18% and 19%, respectively, and a significant improvement of its fracture property was observed. Moreover lower addition of carbon nanotubes to cement mortars can improve its microstructure and decrease the defects significantly compared to the cement mortar without CNTs. With the increase of the content of CNTs, the mechanical properties of cement mortars presented to be declined largely due to the agglomeration of CNTs.

  10. The effect of modified hydrotalcites on mechanical properties and chloride penetration resistance in cement mortar

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.; Polder, R.B.

    2015-01-01

    In this paper, two types of modified hydrotalcites (MHT) were incorporated into cement mortars with two dosage levels (replacing 5% and 10% cement by mass). Designated testing programme including strength test, porosity test, and rapid chloride migration and diffusion test were employed to investiga

  11. Cement content influence in rebar corrosion in carbonated mortars

    Directory of Open Access Journals (Sweden)

    Américo, P. O.

    2003-12-01

    Full Text Available The cement hydration products protect the concrete rebars of the reinforced concrete due to the production of Ca(OH2, NaOH, and KOH that, upon dissolving in the concrete s aqueous phase, generate a pH above 12.5. However, reinforced concrete structures are exposed to pollutant gases, such as, CO2 which upon penetrating the concrete, reacts with the alkaline components, consequently reducing the pH of the aqueous phase causing the loss of passivity by the rebar and as a consequence its corrosion when there is the presence of humidity and oxygen. The objective of the current paper is the analysis of the alkaline reserve influence, measured by the cement content, in the corrosion of rebars employing the polarization resistance technique for determining the corrosion intensity. Results for corrosion intensity of rebars embedded in prismatic mortar test specimens are produced with three cement content levels, with equal water/cement ratio. Cylindrical test specimens were also used for verification of the capillary absorption and the porosity by means of mercury porosymetry The results show that the initiation period is shorter and the corrosion intensity of the rebars is higher when the cement content is lower However, there is also an alteration in the microstructure upon altering the cement content, and far this reason one cannot conclude that the alkaline reserve alone is responsible for these results.

    Los productos de hidratación del cemento protegen las armaduras embebidas en el hormigón debido a la gran cantidad de Ca(OH2, NaOH y KOH disueltos en la fase acuosa del hormigón que proporcionan un pH mayor que 12,5. Sin embargo, las estructuras de hormigón armado están expuestas a los gases contaminantes como el CO2, que al penetrar en el hormigón reacciona con los compuestos alcalinos, se reduce el pH de la fase acuosa y provocan la despasivación de la armadura. Posteriormente, si hay

  12. Quantitative sensing of corroded steel rebar embedded in cement mortar specimens using ultrasonic testing

    Science.gov (United States)

    Owusu Twumasi, Jones; Le, Viet; Tang, Qixiang; Yu, Tzuyang

    2016-04-01

    Corrosion of steel reinforcing bars (rebars) is the primary cause for the deterioration of reinforced concrete structures. Traditional corrosion monitoring methods such as half-cell potential and linear polarization resistance can only detect the presence of corrosion but cannot quantify it. This study presents an experimental investigation of quantifying degree of corrosion of steel rebar inside cement mortar specimens using ultrasonic testing (UT). A UT device with two 54 kHz transducers was used to measure ultrasonic pulse velocity (UPV) of cement mortar, uncorroded and corroded reinforced cement mortar specimens, utilizing the direct transmission method. The results obtained from the study show that UPV decreases linearly with increase in degree of corrosion and corrosion-induced cracks (surface cracks). With respect to quantifying the degree of corrosion, a model was developed by simultaneously fitting UPV and surface crack width measurements to a two-parameter linear model. The proposed model can be used for predicting the degree of corrosion of steel rebar embedded in cement mortar under similar conditions used in this study up to 3.03%. Furthermore, the modeling approach can be applied to corroded reinforced concrete specimens with additional modification. The findings from this study show that UT has the potential of quantifying the degree of corrosion inside reinforced cement mortar specimens.

  13. Carbonatation Influence on Fly Ash and Portland Cement Mortars

    OpenAIRE

    P.L. Valdez–Tamez; A. Durán–Herrera; G. Fajardo–San Miguel; C.A. Juárez–Alvarado

    2009-01-01

    The influence of carbonation on mortars containing 25% of fly ash instead of the cementitious materials was studied. Mortar cylinder specimens were fabricated for 4 different W/C ratios: 0.35, 0.45, 0.55 and 0.65. Mortars with and without fly ash were subjected to an accelerated carbonation process. Volumetric weight, water absorption, compressive strength, water permeability, pH and mercury intrusion porosimetry of the mortar specimens were determined. Due to the fly ash pozzolanic potential...

  14. Utilization of recycled glass derived from cathode ray tube glass as fine aggregate in cement mortar.

    Science.gov (United States)

    Ling, Tung-Chai; Poon, Chi-Sun

    2011-08-30

    Rapid advances in the electronic industry led to an excessive amount of early disposal of older electronic devices such as computer monitors and old televisions (TV) before the end of their useful life. The management of cathode ray tubes (CRT), which have been a key component in computer monitors and TV sets, has become a major environmental problem worldwide. Therefore, there is a pressing need to develop sustainable alternative methods to manage hazardous CRT glass waste. This study assesses the feasibility of utilizing CRT glass as a substitute for natural aggregates in cement mortar. The CRT glass investigated was an acid-washed funnel glass of dismantled CRT from computer monitors and old TV sets. The mechanical properties of mortar mixes containing 0%, 25%, 50%, 75% and 100% of CRT glass were investigated. The potential of the alkali-silica reaction (ASR) and leachability of lead were also evaluated. The results confirmed that the properties of the mortar mixes prepared with CRT glass was similar to that of the control mortar using sand as fine aggregate, and displayed innocuous behaviour in the ASR expansion test. Incorporating CRT glass in cement mortar successfully prevented the leaching of lead. We conclude that it is feasible to utilize CRT glass in cement mortar production.

  15. Utilization of recycled glass derived from cathode ray tube glass as fine aggregate in cement mortar.

    Science.gov (United States)

    Ling, Tung-Chai; Poon, Chi-Sun

    2011-08-30

    Rapid advances in the electronic industry led to an excessive amount of early disposal of older electronic devices such as computer monitors and old televisions (TV) before the end of their useful life. The management of cathode ray tubes (CRT), which have been a key component in computer monitors and TV sets, has become a major environmental problem worldwide. Therefore, there is a pressing need to develop sustainable alternative methods to manage hazardous CRT glass waste. This study assesses the feasibility of utilizing CRT glass as a substitute for natural aggregates in cement mortar. The CRT glass investigated was an acid-washed funnel glass of dismantled CRT from computer monitors and old TV sets. The mechanical properties of mortar mixes containing 0%, 25%, 50%, 75% and 100% of CRT glass were investigated. The potential of the alkali-silica reaction (ASR) and leachability of lead were also evaluated. The results confirmed that the properties of the mortar mixes prepared with CRT glass was similar to that of the control mortar using sand as fine aggregate, and displayed innocuous behaviour in the ASR expansion test. Incorporating CRT glass in cement mortar successfully prevented the leaching of lead. We conclude that it is feasible to utilize CRT glass in cement mortar production. PMID:21705136

  16. Cement Pastes and Mortars Containing Nitrogen-Doped and Oxygen-Functionalized Multiwalled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Mauricio Martínez-Alanis

    2016-01-01

    Full Text Available Cement pastes and mortars based on ordinary Portland cement containing nitrogen-doped multiwalled carbon nanotubes (MWCNT-Nx or oxygen-functionalized multiwalled carbon nanotubes (MWCNT-Ox are investigated. To incorporate MWCNTs into the cementitious matrix, the as-produced carpets are dispersed over periods of 1 and 2 hours in distilled water at pH levels of 1 and 7. The cement pastes are prepared by adding 0.1 wt% of MWCNTs to cement powder, followed by characterization with SEM and X-ray diffraction (XRD at an early age (first hours of hydration. The mortars are mechanically characterized during the hydration process for a period of 28 days. SEM characterization of cement pastes revealed that the carbon nanotubes are well incorporated in the cementitious matrix, with the hydrated cement grains interconnected by long carbon nanotubes. XRD characterizations demonstrated that, during the hydration of cement pastes, different peaks emerged that were associated with ettringite, hydrated calcium silicate, and calcium hydroxide, among other structures. Results of the compressive strength measurements for mortars simultaneously mixed with MWCNT-Nx and MWCNT-Ox reached an increment of approximately 30% in compressive strength. In addition, density functional theory calculations were performed in nitrogen-doped and oxygen-functionalized carbon nanotubes interacting with a cement grain.

  17. Influence of fly ash fineness on water requirement and shrinkage of blended cement mortars

    Directory of Open Access Journals (Sweden)

    Vanissorn Vimonsatit

    2015-12-01

    Full Text Available In this paper, the influence of fly ash fineness on water requirement and shrinkage of blended cement mortar was studied. The results indicate that the water requirement and shrinkage characteristic of the blended cement mortar are dependent on fly ash fineness and replacement level. The use of coarse fly ash slightly reduces the water requirement but greatly reduced the drying and the autogenous shrinkage of the blended cement mortars and the reduction is more with an increase in the fly ash replacement level. The finer fly ashes further reduce the water requirement, but increase the drying and the autogenous shrinkages as compared with coarser fly ash. The incorporation of superplasticizer drastically reduces the water requirement, but the effect on the drying and autogenous shrinkages of the normal Portland cement mortar is small. However, for the fly ash mortar, the use of superplasticizer results in a decrease in drying shrinkage and in a substantial increase in the autogenous shrinkage particularly for the fine fly ash at a high replacement level.

  18. Microstructure engineering of Portland cement pastes and mortars through addition of ultrafine layer silicates

    DEFF Research Database (Denmark)

    Lindgreen, Holger; Geiker, Mette; Krøyer, Hanne;

    2008-01-01

    Pozzolanic submicron-sized silica fume and the non-pozzolanic micron- and nano-sized layer silicates (clay minerals) kaolinite, smectite and palygorskite have been used as additives in Portland cement pastes and mortars. These layer silicates have different particle shape (needles and plates......), surface charge, and size (micron and nano). The structure of the resulting cement pastes and mortars has been investigated by atomic force microscopy (AFM), helium porosimetry, nitrogen adsorption (specific surface area and porosity), low-temperature calorimetry (LTC) and thermal analysis. The main result...

  19. Reuse of cement-solidified municipal incinerator fly ash in cement mortars: physico-mechanical and leaching characteristics.

    Science.gov (United States)

    Cinquepalmi, Maria Anna; Mangialardi, Teresa; Panei, Liliana; Paolini, Antonio Evangelista; Piga, Luigi

    2008-03-01

    The reuse of cement-solidified Municipal Solid Waste Incinerator (MSWI) fly ash (solidified/stabilised (S/S) product) as an artificial aggregate in Portland cement mortars was investigated. The S/S product consisted of a mixture of 48 wt.% washed MSWI fly ash, 20 wt.% Portland cement and 32 wt.% water, aged for 365 days at 20 degrees C and 100% RH. Cement mortars (water/cement weight ratio=0.62) were made with Portland cement, S/S product and natural sand at three replacement levels of sand with S/S product (0%, 10% and 50% by mass). After 28 days of curing at 20 degrees C and 100% RH, the mortar specimens were characterised for their physico-mechanical (porosity, compressive strength) and leaching behaviour. No retardation in strength development, relatively high compressive strengths (up to 36 N/mm2) and low leaching rates of heavy metals (Cr, Cu, Pb and Zn) were always recorded. The leaching data from sequential leach tests on monolithic specimens were successfully elaborated with a pseudo-diffusional model including a chemical retardation factor related to the partial dissolution of contaminant.

  20. Evaluation of sulfate resistance of cement mortars containing black rice husk ash.

    Science.gov (United States)

    Chatveera, B; Lertwattanaruk, P

    2009-03-01

    In this paper, black rice husk ashes (BRHAs), which are agrowastes from an electricity generating power plant and a rice mill, were ground and used as a partial cement replacement. The durability of mortars under sulfate attack including expansion and compressive strength loss were investigated. For parametric study, BRHA were used as a Portland cement Type 1 replacement at the levels of 0%, 10%, 30%, and 50% by weight of binder. The water-to-binder ratios were 0.55 and 0.65. For the durability of mortar exposed to sulfate attack, 5% sodium sulfate (Na2SO4) and magnesium sulfate (MgSO4) solutions were used. As a result, when increasing the percentage replacement of BRHA, the expansion and compressive strength loss of mortar decreased. At the replacement levels of 30% and 50% of BRHA, the expansion of the mortars was less than those mixed with sulfate-resistant cement. However, the expansion of the mortars exposed to Na2SO4 was more than those exposed to MgSO4. Increasing the replacement level of BRHA tends to reduce the compressive strength loss of mortars exposed to Na2SO4 attack. In contrary, under MgSO4 attack, when increasing the replacement level of BRHA, the compressive strength loss increases from 0% to 50% in comparison to Portland cement mortar. Results show that ground BRHA can be applied as a pozzolanic material to concrete and also improve resistance to sodium sulfate attack, but it can impair resistance to magnesium sulfate attack.

  1. Characterization of Mechanical and Bactericidal Properties of Cement Mortars Containing Waste Glass Aggregate and Nanomaterials

    Directory of Open Access Journals (Sweden)

    Pawel Sikora

    2016-08-01

    Full Text Available The recycling of waste glass is a major problem for municipalities worldwide. The problem concerns especially colored waste glass which, due to its low recycling rate as result of high level of impurity, has mostly been dumped into landfills. In recent years, a new use was found for it: instead of creating waste, it can be recycled as an additive in building materials. The aim of the study was to evaluate the possibility of manufacturing sustainable and self-cleaning cement mortars with use of commercially available nanomaterials and brown soda-lime waste glass. Mechanical and bactericidal properties of cement mortars containing brown soda-lime waste glass and commercially available nanomaterials (amorphous nanosilica and cement containing nanocrystalline titanium dioxide were analyzed in terms of waste glass content and the effectiveness of nanomaterials. Quartz sand is replaced with brown waste glass at ratios of 25%, 50%, 75% and 100% by weight. Study has shown that waste glass can act as a successful replacement for sand (up to 100% to produce cement mortars while nanosilica is incorporated. Additionally, a positive effect of waste glass aggregate for bactericidal properties of cement mortars was observed.

  2. Processing of Sugarcane Bagasse ash and Reactivity of Ash-blended Cement Mortar

    Science.gov (United States)

    Ajay, Goyal; Hattori, Kunio; Ogata, Hidehiko; Ashraf, Muhammad

    Sugarcane bagasse ash (SCBA), a sugar-mill waste, has the potential of a partial cement replacement material if processed and obtained under controlled conditions. This paper discusses the reactivity of SCBA obtained by control burning of sugarcane bagasse procured from Punjab province of India. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were employed to ascertain the amorphousness and morphology of the minerals ash particles. Destructive and non-destructive tests were conducted on SCBA-blended mortar specimens. Ash-blended cement paste specimens were analyzed by XRD, thermal analysis, and SEM methods to evaluate the hydration reaction of SCBA with cement. Results showed that the SCBA processed at 600°C for 5 hours was reactive as ash-blended mortar specimens with up to 15% substitution of cement gave better strength than control specimens.

  3. Effects of Specimen Height on the Acoustic Emission Rate Value ‘a’ for Cement Mortar

    Institute of Scientific and Technical Information of China (English)

    WANG Yan; HU Hongxiang; LU Guijuan; CHEN Shijie; LIU Shaojun; WANG Yao

    2016-01-01

    In order to study the size effect on the AE rate ‘a’ value, three kinds of mix ratios were set up by different particle sizes and water cement ratios, 45 cement mortar specimens with ifve different heights were tested under axial compression. And the whole damage processes were monitored by full-digital acoustic emission acquisition system, followed by an analysis of mechanical behavior and AE activity. The experimental results show that the height of the cement specimen has signiifcant effects on the compressive strength and the acoustic emission rate ‘a’ value, but a slight effect on the accumulated AE hits number, which is analyzed from aspects of failure process of cement mortar specimens.

  4. Computation of X-ray powder diffractograms of cement components and its application to phase analysis and hydration performance of OPC cement

    Indian Academy of Sciences (India)

    Rohan Jadhav; N C Debnath

    2011-08-01

    The importance of computed X-ray diffraction patterns of various polymorphs of alite (3, 1, ), belite (, ), aluminate (cubic, orthorhombic), aluminoferrite, gypsum and hemihydrate in the quantitative phase analysis of cement and its early stage hydration performance is highlighted in this work with three OPC samples. The analysis shows that the predominant silicate phases present in all the samples are 3-alite phase and -belite phase, respectively. Both cubic and orthorhombic phases of C3A, brownmillerite, gypsum and hemihydrates are present at different levels. Quantitative phase analysis of cement by Rietveld refinement method provides more accurate and comprehensive data of the phase composition compared to Bogue method. The comparative hydration performance of these samples was studied with / ratio, 0.5 and the results are interpreted in the light of difference in phase compositions viz. -C2S/C3S ratio, fraction of finer cement particles present in the samples and theoretical modeling of C3S hydration.

  5. PERFORMANCE OF CEMENT MORTARS REPLACED BY GROUND WASTE BRICK IN DIFFERENT AGGRESSIVE CONDITIONS

    Directory of Open Access Journals (Sweden)

    ILHAMI DEMIR

    2011-09-01

    Full Text Available This article investigates the sulphate resistance of cement mortars when subjected to different exposure conditions. Cement mortars were prepared using ground waste brick (GWB as a pozzolanic partial replacement for cement at replacement levels of 0%, 2.5%, 5%, 7.5, 10%, 12.5 and 15%. Mortar specimens were stored under three different conditions: continuous curing in lime-saturated tab water (TW, continuous exposure to 5% sodium sulphate solution (SS, and continuous exposure to 5% ammonium nitrate solution (AN, at a temperature of 20 ± 3 ºC, for 7, 28, 90, and 180 days. Prisms with dimensions of 25×25×285 mm, to determine the expansions of the mortar samples; and another set of prisms with dimensions of 40×40×160 mm, were prepared to calculate the compressive strength of the samples. It was determined that the GWB replacement ratios between 2.5% and 10% decreased the 180 days expansion values. The highest compressive strength values were found for the samples with 10% replacement ratio in the TW, SS, and AN conditions for 180 days. The microstructure of the mortars were investigated using scanning electron microscopy (SEM and the Energy dispersive X-ray (EDX.

  6. Inlfuence of Specimen Size on Compression Behavior of Cement Paste and Mortar under High Strain Rates

    Institute of Scientific and Technical Information of China (English)

    CHEN Xudong; CHEN Chen; QIAN Pingping; XU Lingyu

    2016-01-01

    Static and dynamic compression tests were carried out on mortar and paste specimens of three sizes (f68 mm×32 mm,f59 mm×29.5 mm andf32 mm×16 mm) to study the inlfuence of specimen size on the compression behavior of cement-based materials under high strain rates. The static tests were applied using a universal servo-hydraulic system, and the dynamic tests were applied by a spilt Hopkinson pressure bar (SHPB) system. The experimental results show that for mortar and paste specimens, the dynamic compressive strength is greater than the quasi-static one, and the dynamic compressive strength for specimens of large size is lower than those of small size. However, the dynamic increase factors (DIF) has an opposite trend. Obviously, both strain rate and size effect exist in mortar and paste. The test results were then analyzed using Weibull, Carpinteri and Bažant’s size effect laws. A good agreement between these three laws and the test results was reached on the compressive strength. However, for the experimental results of paste and cement mortar, the size effect is not evident for the peak strain and elastic modulus of paste and cement mortar.

  7. Performance Characteristics of Waste Glass Powder Substituting Portland Cement in Mortar Mixtures

    Science.gov (United States)

    Kara, P.; Csetényi, L. J.; Borosnyói, A.

    2016-04-01

    In the present work, soda-lime glass cullet (flint, amber, green) and special glass cullet (soda-alkaline earth-silicate glass coming from low pressure mercury-discharge lamp cullet and incandescent light bulb borosilicate glass waste cullet) were ground into fine powders in a laboratory planetary ball mill for 30 minutes. CEM I 42.5N Portland cement was applied in mortar mixtures, substituted with waste glass powder at levels of 20% and 30%. Characterisation and testing of waste glass powders included fineness by laser diffraction particle size analysis, specific surface area by nitrogen adsorption technique, particle density by pycnometry and chemical analysis by X-ray fluorescence spectrophotometry. Compressive strength, early age shrinkage cracking and drying shrinkage tests, heat of hydration of mortars, temperature of hydration, X-ray diffraction analysis and volume stability tests were performed to observe the influence of waste glass powder substitution for Portland cement on physical and engineering properties of mortar mixtures.

  8. Effect of Functional Chemical Admixtures on the Performance of Cement Asphalt Mortar Used in Ballastless Track

    Institute of Scientific and Technical Information of China (English)

    JIANG Jinyang; SHE Wei; LI Wei; PAN Li

    2015-01-01

    Chemical admixtures are of paramount importance to the performance of modern cement based composites. In this paper, we performed a series of tests to investigate the effects of chemical admixtures on the cement asphalt mortar (CA mortar), i e, compressive strength, frost resistance, permeability, fatigue resistance, pore structure and microstructure. In particular, two types of chemical admixtures were tested,i e, defoamer (tributyl phosphate (TBP)) and polycarboxylate superplasticizer (PS). The results indicate that the addition of TBP and PS eliminates big bubbles and promotes small non-connected pores forming in matrix. Besides, an optimum dosage of TBP and PS may be determined with respect to the frost resistance, permeability and fatigue resistance of CA mortar. Further elaborative discussions are presented as well as experimental evidences from mercury intrusion porosimetry, scanning electron microscopy and energy dispersive spectroscopy.

  9. Application of antifungal CFB to increase the durability of cement mortar.

    Science.gov (United States)

    Park, Jong-Myong; Park, Sung-Jin; Kim, Wha-Jung; Ghim, Sa-Youl

    2012-07-01

    Antifungal cement mortar or microbiological calcium carbonate precipitation on cement surface has been investigated as functional concrete research. However, these research concepts have never been fused with each other. In this study, we introduced the antifungal calciteforming bacteria (CFB) Bacillus aryabhattai KNUC205, isolated from an urban tunnel (Daegu, South Korea). The major fungal deteriogens in urban tunnel, Cladosporium sphaerospermum KNUC253, was used as a sensitive fungal strain. B. aryabhattai KNUC205 showed CaCO3 precipitation on B4 medium. Cracked cement mortar pastes were made and neutralized by modified methods. Subsequently, the mixture of B. aryabhattai KNUC205, conidiospore of C. sphaerospermum KNUC253, and B4 agar was applied to cement cracks and incubated at 18 degrees C for 16 days. B. aryabhattai KNUC205 showed fungal growth inhibition against C. sphaerospermum. Furthermore, B. aryabhattai KNUC205 showed crack remediation ability and water permeability reduction of cement mortar pastes. Taken together, these results suggest that the CaCO3 precipitation and antifungal properties of B. aryabhattai KNUC205 could be used as an effective sealing or coating material that can also prevent deteriorative fungal growth. This study is the first application and evaluation research that incorporates calcite formation with antifungal capabilities of microorganisms for an environment-friendly and more effective protection of cement materials. In this research, the conception of microbial construction materials was expanded.

  10. Standard Test Method for Autogenous Strain of Cement Paste and Mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Lura, Pietro; Goodwin, Fred;

    This test method measures the bulk strain of a sealed cement paste or mortar specimen, including those containing admixtures, various supplementary cementitious materials (SCM), and other fine materials, at constant temperature and not subjected to external forces, from the time of final setting...

  11. Microstructure engineering of Portland cement pastes and mortars through addition of ultrafine layer silicates

    DEFF Research Database (Denmark)

    Lindgreen, Holger; Geiker, Mette Rica; Krøyer, Hanne;

    2008-01-01

    Pozzolanic submicron-sized silica fume and the non-pozzolanic micron- and nano-sized layer silicates (clay minerals) kaolinite, smectite and palygorskite have been used as additives in Portland cement pastes and mortars. These layer silicates have different particle shape (needles and plates...

  12. The application of modified hydrotalcites as chloride scavengers and inhibitor release agents in cement mortars

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.; Polder, R.B.

    2014-01-01

    Owing to the unique molecular structure and high ion exchange capacity, hydrotalcites are believed to have a potential to be modified and tailor-made as an active component of concrete. In this paper, two types of modified hydrotalcites (MHT-pAB and MHT-NO2) were incorporated into cement mortars wit

  13. Properties and Acceleration Mechanism of Cement Mortar Added with Low Alkaline Liquid State Setting Accelerator

    Institute of Scientific and Technical Information of China (English)

    PAN Zhihua; WANG Xuebing; LIU Weiqing

    2014-01-01

    Low alkaline liquid state setting accelerator(LSA) for Portland cement was prepared in laboratory from aqueous solution of several inorganic sulfate salts and some organic chemical substances. Properties of cement with addition of LSA relating to its setting time and strength development as well as its resistance to sulfate attack for short and long term exposure were experimentally examined. The experimental results showed that 5%-7%addition of LSA significantly accelerated the initial and final setting of Portland cement in the presence or absence of the blending of mineral admixtures, the initial and final setting time being less than 3 min and 6 min respectively. Meanwhile, the early 1 day curing age compressive strength increased remarkably by 20%, while the late 28th day curing age compressive strength remained almost unchanged as compared with that of the reference accelerator free cement mortar specimen. Furthermore, mortar specimens of cement added with LSA and exposed to 5%Na2SO4 solution showed their excellent resistance to sulfate attack, with their short and long term curing age resistance coefficient to sulfate attack being around 1.04 to 1.17, all larger than 1.0. XRD analysis on hardened cement paste specimens at very early curing ages of several minutes disclosed the existence of more ettringite in specimens added with LSA than that of the reference specimens, meanwhile SEM observation also revealed the existence of well crystallized ettringite at very early hydration stage, suggesting that the accelerated setting of Portland cement can be attributed to the early and rapid formation of ettringite over the whole cement paste matrix due to the introduction of LSA. MIP measurement revealed that hardened cement paste specimens with the addition of LSA presented less medium diameter pores, more proportion of small pores and less proportion of large capillary pores, which is in a very good coincidence with the improvement of strength development of

  14. Manufacturing of mortars and concretes non-traditionals, by Portland cement, metakaoline and gypsum (15.05%

    Directory of Open Access Journals (Sweden)

    Talero, R.

    1999-12-01

    Full Text Available In a thorough previous research (1, it appeared that creation, evolution and development of the values of compressive mechanical strength (CS and flexural strength (FS, measured in specimens 1x1x6cm of mortar type ASTM C 452-68 (2, manufactured by ordinary Portland cement P-1 (14.11% C3A or PY-6 (0.00% C3A, metakaolin and gypsum (CaSO4∙2H2O -or ternary cements, CT-, were similar to the ones commonly developed in mortars and concretes of OPC. This paper sets up the experimental results obtained from non-traditional mortars and concretes prepared with such ternary cements -TC-, being the portland cement/metakaolin mass ratio, as follows: 80/20, 70/30 and 60/40. Finally, the behaviour of these cements against gypsum attack, has been also determined, using the following parameters: increase in length (ΔL%, compressive, CS, and flexural, FS, strengths, and ultrasound energy, UE. Experimental results obtained from these non-traditional mortars and concretes, show an increase in length (ΔL, in CS and FS, and in UE values, when there is addition of metakaolin.

    En una exhaustiva investigación anterior (1, se pudo comprobar que la creación, evolución y desarrollo de los valores de resistencias mecánicas a compresión, RMC, y flexotracción, RMF, proporcionados por probetas de 1x1x6 cm, de mortero 1:2,75, selenitoso tipo ASTM C 452-68 (2 -que habían sido preparadas con arena de Ottawa, cemento portland, P-1 (14,11% C3A o PY- 6 (0,00% C3A, metacaolín y yeso (CaSO4∙2H2O-, fue semejante a la que, comúnmente, desarrollan los morteros y hormigones tradicionales de cemento portland. En el presente trabajo se exponen los resultados experimentales obtenidos de morteros y hormigones no tradicionales, preparados con dichos cementos ternarios, CT, siendo las proporciones porcentuales en masa ensayadas, cemento portland/metacaolín, las siguientes: 80/20, 70

  15. [Burns caused by cement mortar (based on expert opinion)].

    Science.gov (United States)

    Kleinhans, D

    1984-01-01

    A 35-year-old farmer with scars on his right arm, following erosion obviously due to wet cement (case of an expert opinion), was examined. Cement water had continuously soaked his shirt while he was planing a freshly applied wet cement ceiling with his right arm upwards. The cement did not contain special additives, so the normal alkalinity of wet cement and occlusion effects caused the erosion. The farmer sued the manufacturer of the cement for damages because of missing warning notices. The court decided in his favor.

  16. Effects of blended-cement paste chemical composition changes on some strength gains of blended-mortars.

    Science.gov (United States)

    Kirgiz, Mehmet Serkan

    2014-01-01

    Effects of chemical compositions changes of blended-cement pastes (BCPCCC) on some strength gains of blended cement mortars (BCMSG) were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC) were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP) or 6%, 20%, 21%, and 35% brick powder (BP) for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min). Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC) and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS) and flexural strengths (FS) of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2), sodium oxide (Na2O), and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2) at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM) in comparison with reference mortars (RM) at whole cure days as MP up to 6% or BP up to 35% was blended for cement.

  17. Effects of Blended-Cement Paste Chemical Composition Changes on Some Strength Gains of Blended-Mortars

    Directory of Open Access Journals (Sweden)

    Mehmet Serkan Kirgiz

    2014-01-01

    Full Text Available Effects of chemical compositions changes of blended-cement pastes (BCPCCC on some strength gains of blended cement mortars (BCMSG were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP or 6%, 20%, 21%, and 35% brick powder (BP for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min. Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS and flexural strengths (FS of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2, sodium oxide (Na2O, and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2 at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM in comparison with reference mortars (RM at whole cure days as MP up to 6% or BP up to 35% was blended for cement.

  18. Effect of copolymer latexes on physicomechanical properties of mortar containing high volume fly ash as a replacement material of cement.

    Science.gov (United States)

    Negim, El-Sayed; Kozhamzharova, Latipa; Gulzhakhan, Yeligbayeva; Khatib, Jamal; Bekbayeva, Lyazzat; Williams, Craig

    2014-01-01

    This paper investigates the physicomechanical properties of mortar containing high volume of fly ash (FA) as partial replacement of cement in presence of copolymer latexes. Portland cement (PC) was partially replaced with 0, 10, 20, 30 50, and 60% FA. Copolymer latexes were used based on 2-hydroxyethyl acrylate (2-HEA) and 2-hydroxymethylacrylate (2-HEMA). Testing included workability, setting time, absorption, chemically combined water content, compressive strength, and scanning electron microscopy (SEM). The addition of FA to mortar as replacement of PC affected the physicomechanical properties of mortar. As the content of FA in the concrete increased, the setting times (initial and final) were elongated. The results obtained at 28 days of curing indicate that the maximum properties of mortar occur at around 30% FA. Beyond 30% FA the properties of mortar reduce and at 60% FA the properties of mortar are lower than those of the reference mortar without FA. However, the addition of polymer latexes into mortar containing FA improved most of the physicomechanical properties of mortar at all curing times. Compressive strength, combined water, and workability of mortar containing FA premixed with latexes are higher than those of mortar containing FA without latexes.

  19. Effect of Copolymer Latexes on Physicomechanical Properties of Mortar Containing High Volume Fly Ash as a Replacement Material of Cement

    Directory of Open Access Journals (Sweden)

    El-Sayed Negim

    2014-01-01

    Full Text Available This paper investigates the physicomechanical properties of mortar containing high volume of fly ash (FA as partial replacement of cement in presence of copolymer latexes. Portland cement (PC was partially replaced with 0, 10, 20, 30 50, and 60% FA. Copolymer latexes were used based on 2-hydroxyethyl acrylate (2-HEA and 2-hydroxymethylacrylate (2-HEMA. Testing included workability, setting time, absorption, chemically combined water content, compressive strength, and scanning electron microscopy (SEM. The addition of FA to mortar as replacement of PC affected the physicomechanical properties of mortar. As the content of FA in the concrete increased, the setting times (initial and final were elongated. The results obtained at 28 days of curing indicate that the maximum properties of mortar occur at around 30% FA. Beyond 30% FA the properties of mortar reduce and at 60% FA the properties of mortar are lower than those of the reference mortar without FA. However, the addition of polymer latexes into mortar containing FA improved most of the physicomechanical properties of mortar at all curing times. Compressive strength, combined water, and workability of mortar containing FA premixed with latexes are higher than those of mortar containing FA without latexes.

  20. Investigation on the Effect of Recycled Asphalt Shingle (RAS in Portland Cement Mortar

    Directory of Open Access Journals (Sweden)

    Jinwoo An

    2016-04-01

    Full Text Available Tear-off roofing shingle, referred to as Reclaimed asphalt shingle (RAS, is the byproduct of construction demolition and it is a major solid waste stream in the U.S. Reuse of this byproduct in road construction sector can contribute to the success of materials sustainability as well as landfill conservation. Ground RAS has similar particle distribution as sand and its major component includes aggregate granules, fibers, and asphalt. To promote the beneficial utilization of RAS, this study evaluates the effect of RAS in cement mortar when used as replacement of sand. In addition, the study investigates how cellulose fibers from RAS behave under high alkaline environment during cement hydration process, which may significantly affect mortar’s strength performance. The laboratory study includes measurements of physical, mechanical, and durability behaviors of cement mortar containing RAS replacing sand up to 30%. It was found that the optimum mixture proportions are 5% and 10% for compressive strength and toughness, respectively.

  1. Effect of Cement Asphalt Mortar Debonding on Dynamic Properties of CRTS II Slab Ballastless Track

    Directory of Open Access Journals (Sweden)

    Ping Wang

    2014-01-01

    Full Text Available The debonding of cement emulsified asphalt mortar (CA mortar is one of the main damage types in China railway track system II slab ballastless track. In order to analyze the influence of mortar debonding on the dynamic properties of CRTS II slab ballastless track, a vertical coupling vibration model for a vehicle-track-subgrade system was established on the base of wheel/rail coupling dynamics theory. The effects of different debonding lengths on dynamic response of vehicle and track system were analyzed by using the finite element software. The results show that the debonding of CA mortar layer will increase the dynamic response of track. If the length of debonding exceeds 1.95 m, the inflection point will appear on the vertical displacement curve of track. The vertical vibration acceleration of slab increases 4.95 times and the vertical dynamic compressive stress of CA mortar near the debonding region increases 15 times when the debonding length reaches 3.9 m. Considering the durability of ballastless track, once the length of debonding reaches 1.95 m, the mortar debonding should be repaired.

  2. Chloride ingress in cement paste and mortar measured by Electron Probe Micro Analysis

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    1998-01-01

    is 100-1000 times better than for conventional techniques.The present project is aimed to give a better understanding of the physical-chemical nature of chloride ingress. A number of different cement pastes and mortars are examined ranging from traditional to modern high-performance types. The pastes...... and mortars are exposed to synthetic seawater from 1 day to half a year. Thereafter, the samples are examined by EPMA. Modelling of the measured profiles focuses on a physico-chemical understanding of the mechanisms....

  3. Influence of various acids on the physico–mechanical properties of pozzolanic cement mortars

    Indian Academy of Sciences (India)

    S Türkel; B Felekoǧlu; S Dulluç

    2007-12-01

    Acidic attack represents a topic of increasing significance, owing to the spread of damages of concrete structures in both urban and industrial areas. Cement type is an important factor affecting performance of cement based materials in an aggressive environment. The goal of this study was to compare the acid resistance of a pozzolanic cement (CEM IV-A/32·5) with Portland cement (CEM I 32·5) that was made from the same clinker. For this purpose, 50 mm mortar cubes were prepared with two different kinds of cement according to TS EN 196-1. After 28 days of hardening, the samples were immersed into four different concentrations of hydrochloric, nitric and sulfuric acid solutions for a period of 120 days. The changes in weight loss and compressive strength values for each acid solution within the test period were recorded. The acid resistance of mortars made from Portland cement was better than the pozzolanic cement incorporated samples after 120 days of acid attack.

  4. Effect of Water to Cement Ratio and Age on Portland Composite Cement Mortar Porosity, Strength and Evaporation Rate

    Directory of Open Access Journals (Sweden)

    Enamur R. Latifee

    2016-08-01

    Full Text Available Durability and the compressive strength of concrete are directly related to the porosity. Water to cement ratio is the main parameter behind the nature and amount of pores within the matrix. Porosity is also influenced by the degree of cement hydration and the length of moist-curing. Even after the standard moist curing period, i.e. 28 days the concrete can gain strength and porosity can be reduced under ambient relative humidity and temperature. However, this fact, that is the age effect on porosity reduction of the cement mortar or concrete, kept in air with ambient relative humidity and temperature for long duration could not be found in the literature. Therefore, in this research, different w/c were used with constant amount Portland Composite Cement to find out whether the mortar porosity decreases significantly over time, after 28 days of water curing, while kept in air and if there is any interaction effect between the age of the mortar and different w/c; regarding porosity. It was also intended to find out if water-loss rate variation with different w/c has similar trend as porosity variation with different w/c. It was found that, there is significant decrease in porosity with time for the first six weeks in air and after that it dwindles down gradually, and there is no interaction between age and w/c. Also, after 100 days in air, samples were submerged under water for 24 hours and then kept in air for the evaporation in subsequent days. It has been found that the water evaporation vs. w/c curve, using 11-day evaporation of water from different w/c specimens in ambient condition is almost parallel to porosity vs. w/c curve. Therefore, 11-day evaporation of aged saturated mortar or concrete sample, such as core can also be used as a durability index, which can be used for old structure evaluation.

  5. Some considerations about the use of lime-cement mortars for building conservation purposes in Portugal : a reprehensible option or a lesser evil?

    OpenAIRE

    Torgal, Fernando Pacheco; Faria, Joana; Jalali, Said

    2012-01-01

    Some investigations about conservation actions in historical buildings points out that lime–cement mortars should be avoided and lime–pozzolan mortars should be use instead. Nevertheless this type of mortar is still under investigation and the absolute rejection of the use of Portland cement even with just a minimum amount appears to be a dogmatic position that is not fully grounded in scientific terms. Besides the use of lime–pozzolan mortars requires skilled craftsmanship and at least...

  6. Effect of strain rate and water-to-cement ratio on compressive mechanical behavior of cement mortar

    Institute of Scientific and Technical Information of China (English)

    周继凯; 葛利梅

    2015-01-01

    Effects of strain rate and water-to-cement ratio on the dynamic compressive mechanical behavior of cement mortar are investigated by split Hopkinson pressure bar (SHPB) tests. 124 specimens are subjected to dynamic uniaxial compressive loadings. Strain rate sensitivity of the materials is measured in terms of failure modes, stress−strain curves, compressive strength, dynamic increase factor (DIF) and critical strain at peak stress. A significant change in the stress−strain response of the materials with each order of magnitude increase in strain rate is clearly seen from test results. The slope of the stress−strain curve after peak value for low water-to-cement ratio is steeper than that of high water-to-cement ratio mortar. The compressive strength increases with increasing strain rate. With increase in strain rate, the dynamic increase factor (DIF) increases. However, this increase in DIF with increase in strain rate does not appear to be a function of the water-to-cement ratio. The critical compressive strain increases with the strain rate.

  7. Degree of Hydration of OPC and OPC/Fly ash Paste Samples Conditioned at Different Relative Humidity

    Directory of Open Access Journals (Sweden)

    Nasir Shafiq

    2011-05-01

    Full Text Available Degree of hydration of cement paste controls many properties of hardened concrete and/or mortar such as compressive strength. During the drying process, the degree and the rate of hydration of cement paste in concrete/mortar samples are significantly affected by the ambient relative humidity of the exposure conditions. There are various parameters such as the amount of calcium hydroxide, Ca(OH2 in the paste, quantity of the chemically bound water, specific gravity of the paste, fraction of un-hydrated cement, liberated heat of hydration and strength of the hydrated cement may be used to determine the degree of hydration of the cement paste. This paper presents the results of the experimental investigation for the determination of the degree of hydration of 100% cement paste and fly ash blended cement pastes. After 28 days moist curing, the samples were conditioned in 100%, 75%, 65%, 40% and 12% relative humidity. Conditioning of samples in different relative humidity had significant effects on the compressive strength of the mortar samples and the degree of hydration of the paste samples. Conditioning of samples in 100% RH resulted in higher compressive strength and the degree of hydration. Because of the 28 days moist curing and 12 weeks moisture conditioning in different RH, fly ash based samples showed better compressive strength than the OPC samples.

  8. Effect of Chlorides on Conductivity and Dielectric Constant in Hardened Cement Mortar: NDT for Durability Evaluation

    Directory of Open Access Journals (Sweden)

    Sunkook Kim

    2016-01-01

    Full Text Available Dielectric constant and conductivity, the so-called EM properties (electromagnetic, are widely adopted for NDT (Nondestructive Technique in order to detect damage or evaluate performance of concrete without damage to existing RC (reinforced concrete. Among deteriorating agents, chloride ion is considered as one of the most critical threats due to rapid penetration and direct effect on steel corrosion. In the work, cement mortar samples with 3 w/c (water-to-cement ratios and 4 levels of chloride addition are considered. Conductivity and dielectric constant are measured in the normal frequency range. They increase with strength of mortar and more chloride ions due to denser pore formation. Furthermore, the behaviors of measured EM property are investigated with carbonation velocity and strength, which shows an attempt of application to durability evaluation through EM measurement.

  9. Study on the Carbonation Behavior of Cement Mortar by Electrochemical Impedance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Biqin Dong

    2014-01-01

    Full Text Available A new electrochemical model has been carefully established to explain the carbonation behavior of cement mortar, and the model has been validated by the experimental results. In fact, it is shown by this study that the electrochemical impedance behavior of mortars varies in the process of carbonation. With the cement/sand ratio reduced, the carbonation rate reveals more remarkable. The carbonation process can be quantitatively accessed by a parameter, which can be obtained by means of the electrochemical impedance spectroscopy (EIS-based electrochemical model. It has been found that the parameter is a function of carbonation depth and of carbonation time. Thereby, prediction of carbonation depth can be achieved.

  10. TRANSVERSAL INERTIAL EFFECT ON RELAXATION/RETARDATION TIME OF CEMENT MORTAR UNDER HARMONIC WAVE

    Institute of Scientific and Technical Information of China (English)

    Jue Zhu; Yonghui Cao; Jiankang Chen

    2008-01-01

    Under dynamic loading, the constitutive relation of the cement mortar will be signif-icantly affected by the transversal inertial effect of specimens with large diameters. In this paper,one-dimensional theoretical analysis is carried out to determine the transversal inertial effect on the relaxation/retardation time of the cement mortar under the harmonic wave. Relaxation time or retardation time is obtained by means of the wave velocity, attenuation coefficient and the frequency of the harmonic wave. Thus, the transversal inertial effect on the relaxation time from Maxwell model, as well as on retardation time from Voigt model is analyzed. The results show that the transversal inertial effect may lead to the increase of the relaxation time, but induce the decrease of the retardation time. Those should be taken into account when eliminating the transversal inertial effect in applications.

  11. Short-Term Creep Experiment of Cement Asphalt Mortar and Its Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Hao Xu

    2016-01-01

    Full Text Available In order to investigate the creep performance of cement asphalt mortar (CA mortar, the field sampling of CA mortar cylinder samples was produced, and all samples were tested on WDW series electric universal testing machine by using uniaxial static creep test at 25°C, and the load stress levels were 0.05 MPa, 0.1 MPa, 0.3 MPa, and 0.5 MPa. The greater the load is, the bigger the creep deformation is. The creep performance was simulated by using Burgers model, and the correlation coefficients between fitting results of Burgers model and experimental results are all greater than 0.9. Based on the requirements of finite element software, the Prony series of Burgers model was obtained, and the short-term creep process of CA mortar was simulated by the finite element software ANSYS. The relative error between simulation results and experimental data is not more than 2.5%, which indicates that the short-creep process of CA mortar can be simulated by ANSYS software. The study results can improve the structural design theory of slab track.

  12. Immobilization in cement mortar of chromium removed from water using titania nanoparticles.

    Science.gov (United States)

    Husnain, Ahmed; Qazi, Ishtiaq Ahmed; Khaliq, Wasim; Arshad, Muhammad

    2016-05-01

    Because of the high toxicity of chromium, particularly as Cr (VI), it is removed from industrial effluents before their discharge into water bodies by a variety of techniques, including adsorption. Ultimate disposal of the sludge or the adsorbate, however, is a serious problem. While titania, in nanoparticle form, serves as a very good adsorbent for chromium, as an additive, it also helps to increase the compressive strength of mortar and concrete. Combining these two properties of the material, titania nanoparticles were used to adsorb chromium and then added to mortar up to a concentration of 20% by weight. The compressive strength of the resulting mortar specimens that replaced 15% of cement with chromium laden titania showed an improved strength than that without titania, thus confirming that this material had positive effect on the mortar strength. Leachate tests using the Toxicity Characteristics Leaching Procedure (TCLP) confirmed that the mortar sample chromium leachate was well within the permissible limits. The proposed technique thus offers a safe and viable method for the ultimate disposal of toxic metal wastes, in general, and those laden waste chromium, in particular.

  13. Evaluation of nitric and acetic acid resistance of cement mortars containing high-volume black rice husk ash.

    Science.gov (United States)

    Chatveera, B; Lertwattanaruk, P

    2014-01-15

    This paper presents the performance of cement mortar containing black rice husk ash (BRHA) under nitric and acetic acid attacks. The BRHA, collected from an electrical generating power plant that uses rice husk as fuel, was ground using a grinding machine. The compressive strength loss, weight loss, and expansion of mortars under nitric and acetic acid attack were investigated. The test results of BRHA properties in accordance with the ASTM C 618 standard found that the optimal grinding time was 4 h as this achieved a Blaine fineness of 5370 cm(2)/g. For parametric study, BRHA were used as a Portland cement Type 1 replacement at the levels of 0%, 10%, 20%, 30%, 40%, and 50% by weight of binder. The water-to-binder ratios were 0.55, 0.60, and 0.65. From test results, when the percentage replacements of BRHA in cement increased, it was observed that the strength loss and weight loss of mortars containing BRHA under acetic acid attack were higher than those of the mortars against nitric acid attack. It was found that, of the various BHRA mortars, the strength loss and weight loss due to nitric and acetic acid attacks were the lowest in the mortar with 10% BRHA replacement. For 10%, 20% and 30% BRHA replacements, the rate of expansion of the BRHA mortar decreased when compared with the control mortar. For the mortars with other percentage replacements of BRHA, the rate of expansion increased. Furthermore, the effective water-to-binder ratios of control and BRHA mortars were the primary factor for determining the durability of mortar mixed with BRHA.

  14. Evaluation of red mud as pozzolanic material in replacement of cement for production of mortars

    International Nuclear Information System (INIS)

    Red mud is a by-product of the alkaline extraction of aluminum from the bauxite and represents a renewed environmental problem due the significant annual throughput by the plants. In the present work, the pozzolanic properties of Brazilian red mud fired at 600, 700, 800 and 900 deg C were investigated by monitoring lime consumption using DTA analysis and Brazilian standard methodology NBR 5772 (1992). Products and kinetics of hydration were determined in cement pastes produced with 5 and 15% red mud using x-ray diffraction and DTA analysis. Compressive strength and capillary absorption tests were realized on mortars constituted by 5, 10 and 15% red mud in replacement of cement. When calcined at 600 deg C, the red mud develops good pozzolanic properties, and the compressive strength of mortars produced with this waste meet values in accordance with regulatory standard. These results shown than red mud can be used, in partial replacement of cement, as new construction material to produce sustainable mortars with low environmental impact. (author)

  15. Monitoring accelerated carbonation on standard Portland cement mortar by nonlinear resonance acoustic test

    Science.gov (United States)

    Eiras, J. N.; Kundu, T.; Popovics, J. S.; Monzó, J.; Borrachero, M. V.; Payá, J.

    2015-03-01

    Carbonation is an important deleterious process for concrete structures. Carbonation begins when carbon dioxide (CO2) present in the atmosphere reacts with portlandite producing calcium carbonate (CaCO3). In severe carbonation conditions, C-S-H gel is decomposed into silica gel (SiO2.nH2O) and CaCO3. As a result, concrete pore water pH decreases (usually below 10) and eventually steel reinforcing bars become unprotected from corrosion agents. Usually, the carbonation of the cementing matrix reduces the porosity, because CaCO3 crystals (calcite and vaterite) occupy more volume than portlandite. In this study, an accelerated carbonation-ageing process is conducted on Portland cement mortar samples with water to cement ratio of 0.5. The evolution of the carbonation process on mortar is monitored at different levels of ageing until the mortar is almost fully carbonated. A nondestructive technique based on nonlinear acoustic resonance is used to monitor the variation of the constitutive properties upon carbonation. At selected levels of ageing, the compressive strength is obtained. From fractured surfaces the depth of carbonation is determined with phenolphthalein solution. An image analysis of the fractured surfaces is used to quantify the depth of carbonation. The results from resonant acoustic tests revealed a progressive increase of stiffness and a decrease of material nonlinearity.

  16. Resistance to freezing and thawing of mortar specimens made from sulphoaluminate–belite cement

    Indian Academy of Sciences (India)

    I Janotka; L’ Krajèi

    2000-12-01

    Resistance to freezing and thawing of mortar specimens made from sulphoaluminate–belite cement (M–SAB) is compared with that of mortars made from portland cement (M–PC). The results suggest that larger median radius of the pores and total porosity of M–SAB compared to those of M–PC are primarily caused by the rapid setting of the SAB cement. The `coarsening’ of pore structure of mortar specimens under action of freezing and thawing is proved by the increase in the macropores portion, median pore radius, and total porosity values. This process is more intense in M–SAB. The effect of the frost attack is confirmed by lower compressive strength and dynamic modulus of elasticity on the one hand and higher absorption capacity, expansion, and crack propagation of M–SAB compared with those of M–PC on the other hand. Besides the decreased frost resistance of M–SAB as compared with that of M–PC, unsatisfactory passivation of steel in M–SAB was found. The reason of this fact is the pH value decrease to less than 11.5 of the M–SAB extract.

  17. Application of alkaliphilic biofilm-forming bacteria to improve compressive strength of cement-sand mortar.

    Science.gov (United States)

    Park, Sung-Jin; Chun, Woo-Young; Kim, Wha-Jung; Ghim, Sa-Youl

    2012-03-01

    The application of microorganisms in the field of construction material is rapidly increasing worldwide; however, almost all studies that were investigated were bacterial sources with mineral-producing activity and not with organic substances. The difference in the efficiency of using bacteria as an organic agent is that it could improve the durability of cement material. This study aimed to assess the use of biofilm-forming microorganisms as binding agents to increase the compressive strength of cement-sand material. We isolated 13 alkaliphilic biofilmforming bacteria (ABB) from a cement tetrapod block in the West Sea, Korea. Using 16S RNA sequence analysis, the ABB were partially identified as Bacillus algicola KNUC501 and Exiguobacterium marinum KNUC513. KNUC513 was selected for further study following analysis of pH and biofilm formation. Cement-sand mortar cubes containing KNUC513 exhibited greater compressive strength than mineral-forming bacteria (Sporosarcina pasteurii and Arthrobacter crystallopoietes KNUC403). To determine the biofilm effect, Dnase I was used to suppress the biofilm formation of KNUC513. Field emission scanning electron microscopy image revealed the direct involvement of organic-inorganic substance in cement-sand mortar.

  18. Evaluation of structural behaviour and corrosion resistant of austenitic AISI 304 and duplex AISI 2304 stainless steel reinforcements embedded in ordinary Portland cement mortars; Evaluacion del comportamiento estructural y de resistencia a la corrosion de armaduras de acero inoxidable austenitico AISI 304 y duplex AISI 2304 embebidas en morteros de cemento Portland

    Energy Technology Data Exchange (ETDEWEB)

    Medina, E.; Cobo, A.; Bastidas, D. M.

    2012-07-01

    The mechanical and structural behaviour of two stainless steels reinforcements, with grades austenitic EN 1.4301 (AISI 304) and duplex EN 1.4362 (AISI 2304) have been studied, and compared with the conventional carbon steel B500SD rebar. The study was conducted at three levels: at rebar level, at section level and at structural element level. The different mechanical properties of stainless steel directly influence the behaviour at section level and structural element level. The study of the corrosion behaviour of the two stainless steels has been performed by electrochemical measurements, monitoring the corrosion potential and the lineal polarization resistance (LPR), of reinforcements embedded in ordinary Portland cement (OPC) mortar specimens contaminated with different amount of chloride over one year time exposure. Both stainless steels specimens embedded in OPC mortar remain in the passive state for all the chloride concentration range studied after one year exposure. (Author) 26 refs.

  19. Hydration of portland cement, natural zeolite mortar in water and sulphate solution

    Directory of Open Access Journals (Sweden)

    Janotka, I.

    2003-03-01

    Full Text Available The objective of this paper is to characterise sulphate resistance of mortars made from ordinary Portland cement ( PC and Portland-pozzolan cement with 35 wt.% of zeolite addition (zeolite-blended cement-ZBC . Mortars with two different cement types were tested in water and 5% sodium sulphate solution for 720 days. A favourable effect of zeolite on increased sulphate resistance of the cement is caused by decrease in free Ca(OH2 content of the mortar There is not sufficient of Ca(OH2 available for reacting with the sulphate solution to form voluminous reaction products. A decreased C3A, content due to 35 wt.% replacement of PC by zeolite is the next pronounced factor improving resistance of the mortar with such blended cement.

    El objetivo de este trabajo ha sido estudiar la resistencia a los sulfatos de morteros preparados con cemento portland ordinario (PC y cemento portland puzolánico, con un 35% en peso de zeolita (zeolite-blended cement (ZBC. Ambos tipos de morteros fueron conservados en agua y en una disolución de sulfato sódico al 5% durante 720 días. Se observó una mayor resistencia a los sulfatos en el mortero preparado con el cemento que contenía zeolita debido a su menor contenido en Ca(OH2. No hay cantidad suficiente de Ca(OH2 para que se produzca la reacción de los constituyentes de la pasta con la disolución de sulfato sódico y formar así productos de naturaleza expansiva. La disminución en el contenido de C,3A, debida a la sustitución de un 35% en peso de PC por zeolita, es el factor más determinante en el aumento de la resistencia del mortero en los cementos con adición.

  20. Influence of fly ash fineness on strength, drying shrinkage and sulfate resistance of blended cement mortar

    Energy Technology Data Exchange (ETDEWEB)

    P. Chindaprasirt; S. Homwuttiwong; V. Sirivivatnanon [Khon Kaen University, Khon Kaen (Thailand). Department of Civil Engineering

    2004-07-01

    In this paper, the influence of fineness of fly ash on water demand and some of the properties of hardened mortar are examined. In addition to the original fly ash (OFA), five different fineness values of fly ash were obtained by sieving and by using an air separator. Two sieves, Nos. 200 and 325, were used to obtain two lots of graded fine fly ash. For the classification using air separator, the OFA was separated into fine, medium and coarse portions. The fly ash dosage of 40% by weight of binder was used throughout the experiment. From the tests, it was found that the compressive strength of mortar depended on the fineness of fly ash. The strength of mortar containing fine fly ash was better than that of OFA mortar at all ages with the very fine fly ash giving the highest strength. The use of all fly ashes resulted in significant improvement in drying shrinkage with the coarse fly ash showing the least improvement owing primarily to the high water to binder ratio (W/B) of the mix. Significant improvement of resistance to sulfate expansion was obtained for all fineness values except for the coarse fly ash where greater expansion was observed. The resistance to sulfuric acid attack was also improved with the incorporation of all fly ashes. In this case the coarse fly ash gave the best performance with the lowest rate of the weight loss owing probably to the better bonding of the coarse fly ash particles to the cement matrix and less hydration products. It is suggested that the fine fly ash is more reactive and its use resulted in a denser cement matrix and better mechanical properties of mortar.

  1. Study of the Behavior of Grouting Cement Mortar%注浆用水泥浆体性能研究

    Institute of Scientific and Technical Information of China (English)

    梁乃兴; 陈忠明

    2000-01-01

    对注浆加固公路路基用的水泥浆体从稳定性、流动度、粘滞度、凝结时间、析水率等方面进行了研究.掺加适量的粉煤灰可增加浆体的稳定性,外加剂水玻璃可增加浆体的稳定性及结石率,同时对浆体的流动性有降低作用,而外加剂氯化钙则对浆体的流动性有增强作用.%In this paper, the behavior of grouting cement mortar to reinforce highway subgrade is analyzed from the aspects of stability, fluidity, viscosity, bleeding ratio and setting time of cement mortar. Mixing a certain content of fly ash to cement mortar can improve stability of mortar. Mixing water glass can improve stability and increase forming stone percent of mortar and can reduce the fluidity of mortar. While mixing CaCl2 can increase fluidity of mortar also

  2. 水泥粉煤灰砂浆应用研究%Application of fly ash cement mixed mortar

    Institute of Scientific and Technical Information of China (English)

    陶建红; 李权

    2015-01-01

    As a new type of cement and fly ash mortar is an alternative product in modern ordinary buildings . Orthogonal experiment results show that by using fly ash cement to replace part of the cement in mortar and fly ash mortar , the workability of the mortar is improved , which meets mortar construction and regulatory require-ments.Fly ash cement mixed mortar has good performance , its strength is relatively stable ,helping to ensure the quality of construction projects , while saving costs and protecting the environment .Fly ash cement mixed mortar, as green building materials , is the inevitable trend of future mortar development .%水泥粉煤灰砂浆作为一种新型建筑砂浆,是现代普通建筑砂浆的一种替代产品。通过正交试验结果表明:水泥粉煤灰砂浆通过利用粉煤灰替代部分水泥,提高了砂浆的和易性,满足砌筑砂浆的施工和规范要求。水泥粉煤灰砂浆性能良好,强度比较稳定,有利于保证工程的施工质量,同时节约成本,保护环境。水泥粉煤灰砂浆作为绿色建材是建筑砂浆未来发展的方向之一。

  3. The effect of different surfactants/plastisizers on the electrical behavior of CNT nano-modified cement mortars

    Science.gov (United States)

    Dalla, P. T.; Alafogianni, P.; Tragazikis, I. K.; Exarchos, D. A.; Dassios, K.; Barkoula, N.-M.; Matikas, T. E.

    2015-03-01

    Cement-based materials have in general low electrical conductivity. Electrical conductivity is the measure of the ability of the material to resist the passage of electrical current. The addition of a conductive admixture such as Multi-Walled Carbon Nanotubes (MWCNTs) in a cement-based material increases the conductivity of the structure. This research aims to characterize nano-modified cement mortars with MWCNT reinforcements. Such nano-composites would possess smartness and multi-functionality. Multifunctional properties include electrical, thermal and piezo-electric characteristics. One of these properties, the electrical conductivity, was measured using a custom made apparatus that allows application of known D.C. voltage on the nano-composite. In this study, the influence of different surfactants/plasticizers on CNT nano-modified cement mortar specimens with various concentrations of CNTs (0.2% wt. cement CNTs - 0.8% wt. cement CNTs) on the electrical conductivity is assessed.

  4. Sand/cement ratio evaluation on mortar using neural networks and ultrasonic transmission inspection.

    Science.gov (United States)

    Molero, M; Segura, I; Izquierdo, M A G; Fuente, J V; Anaya, J J

    2009-02-01

    The quality and degradation state of building materials can be determined by nondestructive testing (NDT). These materials are composed of a cementitious matrix and particles or fragments of aggregates. Sand/cement ratio (s/c) provides the final material quality; however, the sand content can mask the matrix properties in a nondestructive measurement. Therefore, s/c ratio estimation is needed in nondestructive characterization of cementitious materials. In this study, a methodology to classify the sand content in mortar is presented. The methodology is based on ultrasonic transmission inspection, data reduction, and features extraction by principal components analysis (PCA), and neural network classification. This evaluation is carried out with several mortar samples, which were made while taking into account different cement types and s/c ratios. The estimated s/c ratio is determined by ultrasonic spectral attenuation with three different broadband transducers (0.5, 1, and 2 MHz). Statistical PCA to reduce the dimension of the captured traces has been applied. Feed-forward neural networks (NNs) are trained using principal components (PCs) and their outputs are used to display the estimated s/c ratios in false color images, showing the s/c ratio distribution of the mortar samples.

  5. Permeability and mechanical properties of cement mortars colored by nano-mineral additives

    Directory of Open Access Journals (Sweden)

    Kamali Bernard S.

    2012-09-01

    Full Text Available This work concerns a preliminary study on issues that relate primarily to the permeability of cementitious materials under the influence of some specific inexpensive additions that can play an important role in preserving the environment. We studied the addition of dyes in the presence of TiO2 on the Portland cement mortar. The used dyes are a yellow powder containing iron oxyhydroxide (FeO (OH, a blue-based powder tellurate manganese (MnTe2O5 and red powder containing iron oxide (Fe2O3. We measure the setting time, permeability and mechanical properties of Portland cement mortars colored with nano-mineral oxides mentioned previously. Test results indicate that the addition of nano-particles has a little influence on the setting time, improves penetration resistance that is due the affinity of the pore structure of mortar and slightly improves the resistance to compression for low levels of nanoparticles of TiO2.

  6. THE INFLUENCE OF JOINT GRINDING OF CEMENT AND COOPER SLAG ON MORTAR PROPERTIES

    Directory of Open Access Journals (Sweden)

    Kravtsov Aleksey Vladimirovich

    2016-08-01

    Full Text Available The problem of applying copper manufacturing waste locating in the Chelyabinsk region as a component of mixed is considered in this article. Application of mixed binder with superplasticizers, based on esters with carboxyl groups, have not sufficiently been studied by the present time due to the diversity of species and complexity of the chemical structure. This trend is current for today’s science because of the growing rates and scales of building production, in particular, of concrete works. Copper slag dumps located in the Ural Federal district haven’t been widely used in building production or in other industrial production by the present time. Efficient utilization of copper production waste materials will help to solve ecological problems in many regions of Russia. Structure formation period of cement stone based on mixed binder made of Portland cement and granulated cooper slag with application of superplasticizer is studied in the article. The authors present a thermal variation diagram of mortar based on mixed binder made of Portland cement and granulated cooper slag in the process of 21 hours of hardening under normal conditions and the results of ultrasound investigation of concrete structure formation period during 5 hours of hardening. The strength development process diagram of mortar based on mixed binder made of Portland cement and granulated cooper slag for 28 days of hardening under normal conditions and the research results of the compressive strength of concrete samples are shown in this article. The obtained characteristics don’t confirm the prospects of applying joint grinding for mortar with the observed kind of non-ferrous metallurgy waste. Also, the obtained results allow us to make a conclusion about little advantages of using this method of binder production. Copper slag can be more effectively used as a component of complex organic and mineral admixture for building production with different purposes and fields

  7. Effects of nano-SiO(2) and different ash particle sizes on sludge ash-cement mortar.

    Science.gov (United States)

    Lin, K L; Chang, W C; Lin, D F; Luo, H L; Tsai, M C

    2008-09-01

    The effects of nano-SiO(2) on three ash particle sizes in mortar were studied by replacing a portion of the cement with incinerated sewage sludge ash. Results indicate that the amount of water needed at standard consistency increased as more nano-SiO(2) was added. Moreover, a reduction in setting time became noticeable for smaller ash particle sizes. The compressive strength of the ash-cement mortar increased as more nano-SiO(2) was added. Additionally, with 2% nano-SiO(2) added and a cure length of 7 days, the compressive strength of the ash-cement mortar with 1 microm ash particle size was about 1.5 times better that of 75microm particle size. Further, nano-SiO(2) functioned to fill pores for ash-cement mortar with different ash particle sizes. However, the effects of this pore-filling varied with ash particle size. Higher amounts of nano-SiO(2) better influenced the ash-cement mortar with larger ash particle sizes.

  8. Effect of metakaolinite on strength and chemical resistance of cement mortars

    Energy Technology Data Exchange (ETDEWEB)

    Malolepszy, J.; Pytel, Z. [Mining and Metallurgy Univ., Faculty of Materials Science and Ceramics, Cracow (Poland)

    2000-07-01

    The effect of the percentage of metakaolinite admixture and calcium aluminate content in portland cement, used as the main cementitious components, on the chemical resistance of a series of prepared standard mortars was investigated. Chemical resistance was evaluated by measuring strength, shrinkage and expansion on the samples stored in water and chemical solutions. Results showed minimal change in the standard properties of mortars by the metakaolinite. However, there was marked improvement in chemical resistance. Interest in the study of this material is related to the urgency of finding a useful application for it, in view of the fact that it is produced in large quantities as a waste-product of power generation. It is widely believed that there is a potential application for this product in improving the durability of concrete. 20 refs., 10 tabs., 9 figs.

  9. Cement content influence in rebar corrosion in carbonated mortars

    OpenAIRE

    Américo, P. O.; A.A. Nepomuceno

    2003-01-01

    The cement hydration products protect the concrete rebars of the reinforced concrete due to the production of Ca(OH)2, NaOH, and KOH that, upon dissolving in the concrete s aqueous phase, generate a pH above 12.5. However, reinforced concrete structures are exposed to pollutant gases, such as, CO2 which upon penetrating the concrete, reacts with the alkaline components, consequently reducing the pH of the aqueous phase causing the loss of passivit...

  10. The Properties of Cement Mortars Modified by Emulsified Epoxy and Micro-fine Slag

    Institute of Scientific and Technical Information of China (English)

    CHEN You-zhi; WANG Hong-xi; MA Zhi-yong; LI Qing-hua

    2003-01-01

    The epoxy resin polymer cement mortars with excellent performances were made up through modifying ordinary Portland cement with emulsified epoxy and micro-fine slag.The microstructure of the epoxy resin polymer cement materials was studied and their hydration and hardening characteristics were discussed by means of modern analysis measures such as SEM,XRD and Hg-intrusion micromeritics.The experimental results indicate that the series effects of water-reducing,density,pozzolanicity,filling and solidification crosslinking through the action together with epoxy organism and micro-fine slag endowed cement-based materials with perfect performances.The main hydration products in the system are C-S-H gel and hydrated calcium aluminate.At later age,AFt can be in existence,and no Ca(OH)2 is found.When epoxy resin is solidified,the organism is in a network structure.In the micro-pore structure of hydrated cement with modified epoxy and fine slag,big harmful pores were fewer,more harmless abundant micro pores were and the possible pore radius was smaller than that of ordinary Portland cement.

  11. Effect of W/C Ratio on Durability and Porosity in Cement Mortar with Constant Cement Amount

    Directory of Open Access Journals (Sweden)

    Yun-Yong Kim

    2014-01-01

    Full Text Available Water is often added to concrete placing for easy workability and finishability in construction site. The additional mixing water can help easy mixing and workability but causes increased porosity, which yields degradation of durability and structural performances. In this paper, cement mortar samples with 0.45 of W/C (water to cement ratio are prepared for control case and durability performances are evaluated with additional water from 0.45 to 0.60 of W/C. Several durability tests including strength, chloride diffusion, air permeability, saturation, and moisture diffusion are performed, and they are analyzed with changed porosity. The changing ratios and patterns of durability performance are evaluated considering pore size distribution, total porosity, and additional water content.

  12. Improved cement mortars by addition of carbonated fly ash from solid waste incinerators

    Directory of Open Access Journals (Sweden)

    López-Zaldívar, O.

    2015-09-01

    Full Text Available This article presents the results of a research developing high performance cement mortars with the addition of municipal solid waste incineration fly ash (MSWIFA stabilized as insoluble carbonates. The encapsulation of hazardous wastes in mortar matrixes has also been achieved. The ashes present high concentrations of chlorides, Zn and Pb. A stabilization process with NaHCO3 has been developed reducing 99% the content of chlorides. Developed mortars replace 10% per weight of the aggregates by treated MSWIFA. Physical/mechanical properties of these mortars have been studied. Presence of Zn, Pb, Cu and Cd has been also analyzed confirming that leaching of these heavy metal ions is mitigated. Conclusions prove better behavior of CAC and CSA mortars than those of CEM-I and CEM-II cement. Results are remarkable for the CAC mortars, improving reference strengths in more than 25%, which make them a fast-curing product suitable for the repair of structures or industrial pavements.Este artículo presenta los resultados del desarrollo de morteros mejorados con la incorporación de cenizas volantes de residuos sólidos urbanos inertizadas en forma de carbonatos. Además se consigue la encapsulación de un residuo peligroso. Las cenizas presentan una alta concentración de cloruros, Zn y Pb. Se ha desarrollado un proceso de estabilización con NaHCO3 reduciendo en un 99% el contenido de cloruros. Los morteros reemplazan un 10% en peso del árido por cenizas tratadas. Se han analizado sus propiedades físico/mecánicas y la presencia de Zn, Pb, Cu y Cd. Se demuestra un mejor comportamiento de los morteros de CAC y CSA que los de CEM-I y CEM-II y se mitiga el lixiviado de metales pesados. Los resultados son significativos en los morteros CAC al mejorar las resistencias de los de referencia en un 25%. Los morteros desarrollados son de curado rápido adecuados para la reparación de estructuras o soleras industriales.

  13. Behavior of limestone filler cement mortars exposed to magnesium sulfate attack

    Directory of Open Access Journals (Sweden)

    Senhadji Y.

    2014-04-01

    Full Text Available In the cement production industry, looking for a less expensive binder using industrial waste and natural resources has become a major concern for the deficit level in the manufacture of Portland cement. However, despite the technical, economic and environmental benefits brought by the use of blended cements, they are associated with disadvantages. The objective of this paper is to study the effects of the incorporation of limestone fillers on the mechanical properties and durability of mortars prepared in different combinations based on this admixture material. The durability was evaluated after immersing the specimens in a 5% solution of magnesium sulfate for periods up to 360 days, and the penetration of chloride ions. The test results demonstrated that mortar and paste samples incorporating higher replacement levels of limestone filler were more susceptible to sulfate attack. According to microstructural analysis, such as DRX, the deterioration was significantly associated with formation of thaumasite, gypsum, and the brucite in the deteriorated parts of the specimens.

  14. 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.

  15. Shrinkage and Cracking Sensitivity of Cement Mortar Containing Fly Ash, Granulated Blast-furnace Slag and Silica Fume

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A laboratory study was undertaken to investigate drying shrinkage and cracking sensitivity subjected to restrained shrinkage of mortar containing fly ash (FA), granulated blast-furnace slag (GBFS) and silica fume (SF). Six mortar mixtures including control Portland cement (PC) and FA,GBFS and SF mortar mixtures were prepared. FA replaced the cement on mass basis at the replacement ratios of 20% and 35%, GBFS replaced the cement at the replacement ratios of 40%, SF replaced the cement at the replacement ratios of 8% and the blended mixtures with 20% FA, 20% GBFS and 8% SF. Water-cementitious materials ratio and sand-cementitious materials ratio were 0.4 and 2.0 for all mixtures, respectively. The mixtures were cured at 65% relative humidity and 20℃. The drying shrinkage value, initial cracking time and cracking width of the mortar samples were measured. The results show that all the mortar mixture containing FA exhibited the decrease of drying shrinkage.Moreover, initial cracking time was markedly delayed, and the crack width of the initial crack was reduced. However, the incorporations of various ratios of GBFS and SF led to an increase of drying shrinkage, initial cracking time and cracking width as compared to control mixture.

  16. Behaviour of alkaline cement mortars reinforced with acrylic and polypropylene fibres

    OpenAIRE

    Puertas, P.; Amat, T.; Vázquez, T.

    2000-01-01

    In the present work, the behaviour of alkaline cement mortars reinforced with fibres of different nature (acrylic and polypropylene fibres) is studied. Also the chemical stability of those fibres in strong alkaline medium has been investigated. Three different matrixes have been used: glass blast furnace slag activated with NaOH 2M (room temperature, 22 ºC); fly ash activated with NaOH 8M, cured at 85ºC during 24 hours and 50% fly ash / 50% slag activated with NaOH 8M, room temperature. The f...

  17. Interaction of Shock Waves in Cement Mortar Plate Investigated by the Digital Speckle Correlation Method

    Institute of Scientific and Technical Information of China (English)

    LI Xu-Dong; LIU Kai-Xin; ZHANG Guang-Sheng; WEN Shang-Gang; TAN Fu-Li

    2008-01-01

    @@ Interaction of shock waves in cement mortar plate is studied by digital speckle correlation method and digital high-speed photography technique. When the plates were destroyed by two detonators exploding at the same time, variation of shock wave field is obtained. Experimental results show that the interaction of shock waves will result in a nonlinear huge increase of local normal strain, leading to large deformation and serious destruction. However, the occurrence of this strongly nonlinear phenomenon sensitively depends on the interval between detonators, and it will only appear when the interval is smaller than the diameter of the region where shock waves exist.

  18. Evaluation of compressive strength in cement mortars, according to the dosage established by the colombian seismic resistance code. Case study

    Directory of Open Access Journals (Sweden)

    Sergio Giovanny Valbuena Porras

    2016-06-01

    Full Text Available Context: In a masonry wall the mortar it is between 10 and 20% of the total volume of the system, despite its effect on the behavior of it is significantly higher than this percentage indicates.Objective: The purpose of this research was to evaluate the resistance to compression of two types of mortar paste (A and B, prepared with natural sand from the town of Usme in Bogotá, in accordance with the proportions set by the Standard Colombian earthquake Resistant regulation (NSR-10.Method: Two types of mortar paste were prepared, according to the proportions of cement and sand established in NSR-10 section D.3.4-1 of (Table 1; these proportions were calculated using a 0.0028 m3 container for measuring unit weight. For type A mortar rock sand was used and river sand for type B mortar.Results: The resistance to compression for mortars type A at the end of the study was on average 84% of the expected resistance, whereas for type B mortars it averaged 64% above the expected resistance.Conclusion: Mortar mixes made with crushed or rock (type A arena do not reach the compressive strength required demanded by regulatory standards, despite complying with the dosage established in NSR 10 and with NTC quality criteria; while the natural sand origin or natural river sand meet these standards.

  19. Recycling municipal incinerator fly- and scrubber-ash into fused slag for the substantial replacement of cement in cement-mortars.

    Science.gov (United States)

    Lee, Tzen-Chin; Rao, Ming-Kang

    2009-06-01

    Fly- and scrubber-ash (weight ratio of approximately 1:3) from municipal solid waste incinerators (MSWI) are a major land-fill disposal problem due to their leaching of heavy metals. We uniformly mixed both types of ash with optimal amounts of waste glass frit, which was then melted into a glassy slag. The glassy slag was then pulverized to a particle size smaller than 38microm for use as a cement substitute (20-40% of total cement) and blended with sand and cement to produce slag-blended cement-mortar (SCM) specimens. The toxicity characteristics of the leaching procedure tests on the pulverized slag samples revealed that the amount of leached heavy metals was far below regulatory thresholds. The compressive strength of the 28-day cured SCM specimens was comparable to that of ordinary Portland cement mortars, while the compressive strength of specimens cured for 60 or 90 days were 3-11% greater. The observed enhanced strength is achieved by Pozzolanic reaction. Preliminary evaluation shows that the combination of MSWI fly- and scrubber-ash with waste glass yields a cost effective and environmentally friendly cement replacement in cement-mortars.

  20. Chemo-physical modeling of cement mortar hydration: Role of aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jena, E-mail: jeong@profs.estp.fr [Université Paris-Est, Institut de Recherche en Constructibilité, ESTP, 28 Avenue Président Wilson, 94234 Cachan (France); Ramézani, Hamidréza, E-mail: hamidreza.ramezani@univ-orleans.fr [CRMD, CNRS FRE 3520-Research Center on Divided Materials, École Polytechnique de l’Université d’Orléans, 8 rue Léonrad de Vinci, 45072 Orléans Cedex 2 (France); Leklou, Nordine, E-mail: nordine.leklou@univ-nantes.fr [LUNAM Université, Université de Nantes-IUT Saint-Nazaire, GeM, CNRS UMR 6183, Research Institute in Civil Engineering and Mechanics, 58 rue Michel Ange BP 420 44606 Saint Nazaire Cedex (France); Mounanga, Pierre, E-mail: pierre.mounanga@univ-nantes.fr [LUNAM Université, Université de Nantes-IUT Saint-Nazaire, GeM, CNRS UMR 6183, Research Institute in Civil Engineering and Mechanics, 58 rue Michel Ange BP 420 44606 Saint Nazaire Cedex (France)

    2013-07-20

    Graphical abstract: - Abstract: After mixing of the cement with water, most of the anhydride products sustain the hydration process and this leads to the hydrate products, e.g. CSH, Ca(OH){sub 2}, Afm and Aft. The mentioned hydration process is a highly complex phenomenon involving the chemically based thermo-activation inside the cement mortars during the early age hydration process. The chemo-thermal hydration reactions drasticaly increase at the early age of hydration after the mixing action and then it becomes less important and turns to be nearly asymptotic. The progress of the hydration phenomenon drives the material properties change during the very early age of cement hydration. Regarding the mortar and concrete, such hydration process would not be homogeneous through the cement matrix due to the aggregates presence. These inclusions will affect the temperature distribution as well as degree of hydration. In the current contribution, the chemical and thermal hydration have been firstly investigated by means of SEM observations using replica method and secondly by the 3D-FEM numerical experiments including two different case studies using glass beads as aggregates. The numerical experiments match fairly good the experimental measurements obtained using a pseudo-adiabatic testing setup for the case studies herein. The scanning electron microscopy (SEM) images observation demonstrates the gap spaces around the glass beads next to the external surfaces. These gaps can be essentially seen for the multi-glass beads case study. The role of the temperature and degree of hydration gradients are clearly obtained using the numerical samples. Some fresh routes and outlooks have been afterwards discussed.

  1. Lime mud from cellulose industry as raw material in cement mortars

    Directory of Open Access Journals (Sweden)

    Modolo, R. C.E.

    2014-12-01

    Full Text Available This study reports the use of lime mud (LM in cement-based-mortars. Lime mud is a waste generated in the production of cellulose by the kraft mill process. It is mainly composed of CaCO3, a small amount of magnesium carbonate and other trace minerals. Mortars were prepared by adding different amounts of LM (10, 20 and 30% by weight of cement in dry weight. The mortar compositions were evaluated through rheology and flow table measurements, assuring that all the samples exhibited adequate conditions for testing in both equipments. The hardened state properties were also evaluated through mechanical strengths at 7, 28 and 90 days of curing. Following a waste management solution perspective, this work intend to provide a general evaluation of LM application in cement based mortars, looking at both fresh and hardened properties in order to guarantee that the final application requirements are not hindered.Este estudio revela el uso de lodo de carbonato (LM en morteros de cemento. El LM es un residuo compuesto principalmente por CaCO3 generado en la producción de pasta de papel por el método Kraft. Los morteros se prepararon a partir de la adición de diferentes niveles de LM (10, 20 y 30% en peso de cemento en peso seco. Las composiciones de los morteros fueron caracterizadas através de mediciones de reología de mesa y de flujo, asegurando que las muestras exhibían condiciones adecuadas para su caracterización en ambos equipamientos. Las propiedades en estado endurecido también se evaluaron através de resistencias mecánicas a los 7, 28 y 90 días de cura. Con objeto de gestión de residuos, este trabajo tiene la intención de proporcionar una visión general de la aplicación de LM en los morteros, haciendo hincapié en las propiedades con el fin de garantizar que los requisitos para su aplicación final no se vean obstaculizados.

  2. Utilization of recycled cathode ray tubes glass in cement mortar for X-ray radiation-shielding applications.

    Science.gov (United States)

    Ling, Tung-Chai; Poon, Chi-Sun; Lam, Wai-Shung; Chan, Tai-Po; Fung, Karl Ka-Lok

    2012-01-15

    Recycled glass derived from cathode ray tubes (CRT) glass with a specific gravity of approximately 3.0 g/cm(3) can be potentially suitable to be used as fine aggregate for preparing cement mortars for X-ray radiation-shielding applications. In this work, the effects of using crushed glass derived from crushed CRT funnel glass (both acid washed and unwashed) and crushed ordinary beverage container glass at different replacement levels (0%, 25%, 50%, 75% and 100% by volume) of sand on the mechanical properties (strength and density) and radiation-shielding performance of the cement-sand mortars were studied. The results show that all the prepared mortars had compressive strength values greater than 30 MPa which are suitable for most building applications based on ASTM C 270. The density and shielding performance of the mortar prepared with ordinary crushed (lead-free) glass was similar to the control mortar. However, a significant enhancement of radiation-shielding was achieved when the CRT glasses were used due to the presence of lead in the glass. In addition, the radiation shielding contribution of CRT glasses was more pronounced when the mortar was subject to a higher level of X-ray energy.

  3. [Dynamic leaching behavior of heavy metals in eco-cement mortar block].

    Science.gov (United States)

    Li, Cheng; Liu, Jian-Guo; Zhang, Jun-Li; Yue, Dong-Bei; Nie, Yong-Feng; Wang, Chang-Hai

    2008-03-01

    A dynamic leaching test with the renewal of acidic leaching medium was designed to study the leaching behavior of the seven heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn) in three solidified eco-cement mortar samples with different particle size (fine granule, coarse granule, block) under a long-term leaching condition. It was demonstrated that all the heavy metals were detected in the leachate except Cd. The leaching ratio of Cr was the highest when compared with other metals in the same sample, and the leaching ratio of every metal showed an identical tendency: fine granule> coarse granule > block. The on-going leaching part of the relationship curve of accumulative leaching point (Pt) and t1/2 of each metal presented a fairly good linearity, which indicated that the leaching process was under the control of diffusion mechanism by the Fick Law. To each metal, the effective diffusion coefficient (Deff) showed a tendency of fine granule < coarse granule < block, which was opposite to the tendency of leaching ratio. It could be concluded that the solidified eco-cement mortar with a bigger size would have a lower leaching ratio and a shorter period to finish the leaching test. To all the metals, the Deff was very low, with the magnitude around 10(-10) cm2/s, which meant the leaching process would take a relatively long time. PMID:18649553

  4. Study on cement mortar and concrete made with sewage sludge ash.

    Science.gov (United States)

    Chang, F C; Lin, J D; Tsai, C C; Wang, K S

    2010-01-01

    This study investigated the feasibility of reusing wastewater sludge ash in construction materials to replace partial materials. Wastewater sludge sampled from thermal power plant was burned into sludge ash at 800°C in the laboratory. The sludge incineration ash has low heavy metal including Pb, Cd, Cr and Cu, so it belongs to general enterprise waste. The chemical composition of sludge incineration ash was summed up in SiO₂, CaO, Fe₂O₃ and MgO. Then the wastewater sludge ash is also found to be a porous material with irregular surface. When the sludge ash was used to replace mortar or concrete cement, its water-adsorption capability will result in the reduction of mortar workability and compressive strength. Cement is being substituted for sludge ash, and 10 percent of sludge ash is more appropriate. Sludge ash is reused to take the place of construction materials and satisfies the requests of standard specification except for higher water absorption.

  5. Potential Use Of Carbide Lime Waste As An Alternative Material To Conventional Hydrated Lime Of Cement-Lime Mortars

    OpenAIRE

    Al Khaja, Waheeb A.

    1992-01-01

    The present study aimed at the possibility of using the carbide lime waste as an alternative material to the conventional lime used for cement-lime mortar. The waste is a by-product obtained in the generation of acetylene from calcium carbide. Physical and chemical properties of the wastes were studied. Two cement-lime-sand mix proportions containing carbide lime waste were compared with the same mix proportions containing conventional lime along with a control mix without lime. Specimens wer...

  6. Reuse of By-Products from Ready-Mixed Concrete Plants for the Production of Cement Mortars

    Directory of Open Access Journals (Sweden)

    Monika Zervaki

    2013-06-01

    Full Text Available This study was motivated by the necessity to recycle sludge water resulting from washing out concrete mixing trucks - a problem of both environmental and economic importance for the ready-mixed concrete industry. Sludge water from ready-mixed concrete plants as well as dry sludge, which is derived from the settling of the water, are hazardous for disposal due to their high pH value (pH>11.5. In this work, cement mortars were composed using either sludge water after various treatment, or dry sludge in several ratios. The cement mortars were tested for their workability and strength development. The purpose of this experimental design was to prove that sludge water, as well as sludge in a wet or dry form, can be used in the production of mortars without degrading any of their properties.

  7. Mechanical characterization of Portland cement mortars containing petroleum or coal tar

    Directory of Open Access Journals (Sweden)

    Garcés, P.

    2007-08-01

    Full Text Available This article discusses experimental data on the flexural and compressive strength of Portland cement mortars containing additions or cement replacements consisting in petroleum or coal tar, by-products of the oil and coal industries. The materials studied were two coal (BACA and BACB and two petroleum (BPP and BPT tars. The results show that it is feasible to use such materials as a partial replacement for cement in mortar manufacture. This should lead to the design of a new sustainable product that will contribute to lowering the environmental impact of construction materials while at the same time opening up an avenue for the re-use of this type of industrial by-products.En este artículo se presentan datos experimentales de resistencia a flexión y a compresión de morteros de cemento Portland con adición y sustitución de breas de petróleo y de alquitrán de carbón, que son subproductos de la industria del carbón o del petróleo. Los materiales estudiados son breas de alquitrán de carbón A (BACA y B (BACB, y dos breas de petróleo (BPP y (BPT. Los datos demuestran la viabilidad del uso de estas breas en la fabricación de morteros con menores contenidos de cemento, permitiendo diseñar un nuevo material sostenible con el medio ambiente y que contribuya a reducir el impacto ambiental de los materiales de construcción, hecho que permite abrir una nueva vía de valorización de estos subproductos.

  8. Dry and wet "deposition" studies of the degradation of cement mortars

    Directory of Open Access Journals (Sweden)

    Martínez-Ramírez, S.

    1998-06-01

    Full Text Available The reaction of portland cement mortars with SO2 gaseous pollutant and artificial 'acid rain' solution has been examined using laboratory exposure chambers, with realistic presentation rates of pollutants. The mortar were previously carbonated to produce superficial carbonation. Two mortars with different w/c ratio and hence specific surface were prepared and exposed into the chambers. For dry deposition of SO2 pollutant gas, the important roles of water and water plus oxidant in increasing chemical reaction are readily revealed. Further, accessible porosity also increases reaction through increased times of reaction of pollutant with the mortars. Interestingly, in the absence of deliberate surface wetting, the presence of oxidant, ozone, leads to a reduction in the already limited extent of reaction. Wet deposition studies using artificial 'acid rain' solution result in gypsum formation, which is more extensive for mortars of increased w/c ratios.

    Se han realizado ensayos de laboratorio de simulación de los procesos ambientales de "deposición" seca y húmeda sobre morteros de cemento portland, estudiándose las reacciones que se producen con el contaminante SO2 ("deposición" seca y la disolución de 'lluvia acida' ("deposición" húmeda. Los morteros de cemento se carbonataron para favorecer la carbonatación superficial de los mismos. Se prepararon morteros con dos relaciones a/c con el fin de estudiar la influencia que la variable superficie específica tenía en el proceso de deterioro de dichos materiales. En los estudios de deposición seca con SO2 como gas agresivo se ha visto la importancia que el agua y el agua junto a un oxidante tienen en la reacción del contaminante con los componentes del mortero. La superficie específica Juega un papel importante, ya que al aumentar, aumenta la reacción con el contaminante. La reacción en presencia de oxidante, (SO2+O3

  9. Assessment of Pb-slag, MSWI bottom ash and boiler and fly ash for using as a fine aggregate in cement mortar.

    Science.gov (United States)

    Saikia, Nabajyoti; Cornelis, Geert; Mertens, Gilles; Elsen, Jan; Van Balen, Koenraad; Van Gerven, Tom; Vandecasteele, Carlo

    2008-06-15

    Three types of wastes, metallurgical slag from Pb production (SLG), the sand-sized (0.1-2 mm) fraction of MSWI bottom ash from a grate furnace (SF), and boiler and fly ash from a fluidised bed incinerator (BFA), were characterized and used to replace the fine aggregate during preparation of cement mortar. The chemical and mineralogical behaviour of these wastes along with the reactivities of the wastes with lime and the hydration behaviour of ordinary Portland cement paste with and without these wastes added were evaluated by various chemical and instrumental techniques. The compressive strengths of the cement mortars containing waste as a partial substitution of fine aggregates were also assessed. Finally, leaching studies of the wastes and waste containing cement mortars were conducted. SLG addition does not show any adverse affect during the hydration of cement, or on the compressive strengths behaviours of mortars. Formation of expansive products like ettringite, aluminium hydroxide and H2 gas due to the reaction of some constituents of BFA and SF with alkali creates some cracks in the paste as well as in the cement mortars, which lower the compressive strength of the cement mortars. However, utilization of all materials in cement-based application significantly improves the leaching behaviour of the majority of the toxic elements compared to the waste as such.

  10. On the Utilization of Pozzolanic Wastes as an Alternative Resource of Cement

    Directory of Open Access Journals (Sweden)

    Md. Rezaul Karim

    2014-12-01

    Full Text Available Recently, as a supplement of cement, the utilization of pozzolanic materials in cement and concrete manufacturing has increased significantly. This study investigates the scope to use pozzolanic wastes (slag, palm oil fuel ash and rice husk ash as an alkali activated binder (AAB that can be used as an alternative to cement. To activate these materials, sodium hydroxide solution was used at 1.0, 2.5 and 5.0 molar concentration added into the mortar, separately. The required solution was used to maintain the flow of mortar at 110% ± 5%. The consistency and setting time of the AAB-paste were determined. Mortar was tested for its flow, compressive strength, porosity, water absorption and thermal resistance (heating at 700 °C and investigated by scanning electron microscopy. The experimental results reveal that AAB-mortar exhibits less flow than that of ordinary Portland cement (OPC. Surprisingly, AAB-mortars (with 2.5 molar solution achieved a compressive strength of 34.3 MPa at 28 days, while OPC shows that of 43.9 MPa under the same conditions. Although water absorption and porosity of the AAB-mortar are slightly high, it shows excellent thermal resistance compared to OPC. Therefore, based on the test results, it can be concluded that in the presence of a chemical activator, the aforementioned pozzolans can be used as an alternative material for cement.

  11. SEM Analysis of the Interfacial Transition Zone between Cement-Glass Powder Paste and Aggregate of Mortar under Microwave Curing

    Directory of Open Access Journals (Sweden)

    Yaning Kong

    2016-08-01

    Full Text Available In order to investigate the effects of microwave curing on the microstructure of the interfacial transition zone of mortar prepared with a composite binder containing glass powder and to explain the mechanism of microwave curing on the improvement of compressive strength, in this study, the compressive strength of mortar under microwave curing was compared against mortar cured using (a normal curing at 20 ± 1 °C with relative humidity (RH > 90%; (b steam curing at 40 °C for 10 h; and (c steam curing at 80 °C for 4 h. The microstructure of the interfacial transition zone of mortar under the four curing regimes was analyzed by Scanning electron microscopy (SEM. The results showed that the improvement of the compressive strength of mortar under microwave curing can be attributed to the amelioration of the microstructure of the interfacial transition zone. The hydration degree of cement is accelerated by the thermal effect of microwave curing and Na+ partially dissolved from the fine glass powder to form more reticular calcium silicate hydrate, which connects the aggregate, calcium hydroxide, and non-hydrated cement and glass powder into a denser integral structure. In addition, a more stable triangular structure of calcium hydroxide contributes to the improvement of compressive strength.

  12. Using Neutron Radiography to Quantify Water Transport and the Degree of Saturation in Entrained Air Cement Based Mortar

    Science.gov (United States)

    Lucero, Catherine L.; Bentz, Dale P.; Hussey, Daniel S.; Jacobson, David L.; Weiss, W. Jason

    Air entrainment is commonly added to concrete to help in reducing the potential for freeze thaw damage. It is hypothesized that the entrained air voids remain unsaturated or partially saturated long after the smaller pores fill with water. Small gel and capillary pores in the cement matrix fill quickly on exposure to water, but larger pores (entrapped and entrained air voids) require longer times or other methods to achieve saturation. As such, it is important to quantitatively determine the water content and degree of saturation in air entrained cementitious materials. In order to further investigate properties of cement-based mortar, a model based on Beer's Law has been developed to interpret neutron radiographs. This model is a powerful tool for analyzing images acquired from neutron radiography. A mortar with a known volume of aggregate, water to cement ratio and degree of hydration can be imaged and the degree of saturation can be estimated.

  13. Pozzolanic Activity of Burned Coal Gangue and Its Effects on Structure of Cement Mortar

    Institute of Scientific and Technical Information of China (English)

    ZHANG Changsen

    2006-01-01

    The pozzolanic activity of coal gangue burned at different burning temperatures was investigated. The burned coal gangue was mixed with portland cement in different proportions ( 20%-60% ). The pozzolanic activity of coal gangue burned and the hydration products were examined, the compressive strengths of the pastes of the mixtures were tested, and the mechanism of the reaction was discussed. The experimental results show that the coal gangue burned at 750 ℃ has the optimum pozzolanic activity, and the burned coal gangue with SiO2 and Al2O3 is in an active form. When the coal gangue burned at 750 ℃ is mixed into portland cement, the content of calcium hydroxide in paste is significantly reduced, while the contents of hydrated calcium silicate and hydrated calcium aluminate are increased accordingly, hence resulting in the improvement of the microstructure of mortar. The compressive strength of cement paste decreases with increasing the content of burned coal gangue. The decease in strength is small in the range of 20%- 30% coal gangue substitution and significant in 30%- 60% substitution.

  14. Physico-chemical studies of gamma-irradiated polyester. Impregnated cement mortar composite

    International Nuclear Information System (INIS)

    The effect of impregnation time on the physico-chemical and mechanical properties of polyester-cement mortar composite has been investigated. The samples were soaked in unsaturated polyester resin containing 40% styrene monomer at impregnation times ranging from 1-15 hours and then exposed to 50 kGy of γ-irradiation. The effects on polymer loading, compressive strength, apparent porosity, and water absorption in addition to IR spectra and TGA of the samples were studied. It was found that, the polymer loading and compressive strength increase with the increased of soaking time up to 4 hours and there is no significant improvement of the polymer loading and strength. Whereas, the apparent porosity and water absorption behave in an opposite direction. These are attributed to the presence of polymer in the pores of the samples. IR spectra showed that, new bands appeared as result of the reaction between polyester and set cement. TGA showed that, the polyester cement composite has higher thermal stability as a compared to irradiated polyester. (author)

  15. [Dynamic leaching behavior of heavy metals in eco-cement mortar block].

    Science.gov (United States)

    Li, Cheng; Liu, Jian-Guo; Zhang, Jun-Li; Yue, Dong-Bei; Nie, Yong-Feng; Wang, Chang-Hai

    2008-03-01

    A dynamic leaching test with the renewal of acidic leaching medium was designed to study the leaching behavior of the seven heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn) in three solidified eco-cement mortar samples with different particle size (fine granule, coarse granule, block) under a long-term leaching condition. It was demonstrated that all the heavy metals were detected in the leachate except Cd. The leaching ratio of Cr was the highest when compared with other metals in the same sample, and the leaching ratio of every metal showed an identical tendency: fine granule> coarse granule > block. The on-going leaching part of the relationship curve of accumulative leaching point (Pt) and t1/2 of each metal presented a fairly good linearity, which indicated that the leaching process was under the control of diffusion mechanism by the Fick Law. To each metal, the effective diffusion coefficient (Deff) showed a tendency of fine granule mortar with a bigger size would have a lower leaching ratio and a shorter period to finish the leaching test. To all the metals, the Deff was very low, with the magnitude around 10(-10) cm2/s, which meant the leaching process would take a relatively long time.

  16. Effects of Two Redispersible Polymer Powders on Efflorescence of Portland Cement-based Decorative Mortar

    Directory of Open Access Journals (Sweden)

    Huimei ZHU

    2014-09-01

    Full Text Available The effects of redispersible polymer powders of ethylene/Vinyl acetate copolymer (EVA and ethylene/vinyl laurate/vinyl chloride terpolymer (E/VL/VC on the efflorescence of Portland cement-based decorative mortar (PCBDM were studied. The results showed that EVA slightly prolongs the efflorescence duration of fresh PCBDM; and exacerbates efflorescence of hardened PCBDM, because it increases the content of soluble salts such as Ca2+, K+, Na+ ions in hardened PCBDM and promotes their migration. E/VL/VC exacerbates efflorescence of fresh PCBDM due to it easily dissolves in the surface water; but reduces efflorescence of hardened PCBDM, which is attributed to that it decreases the soluble salts content in hardened PCBDM and prohibits salts migration. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4053

  17. Altered cement hydration and subsequently modified porosity, permeability and compressive strength of mortar specimens due to the influence of electrical current

    NARCIS (Netherlands)

    Susanto, A.; Koleva, D.A.; Van Breugel, K.

    2014-01-01

    This paper reports on the influence of stray current flow on microstructural prop-erties, i.e. pore connectivity and permeability of mortar specimens, and link these to the observed alterations in mechanical properties and cement hydration. Mortar specimens were partly submerged in water and calcium

  18. Simple method of dynamic Young’s modulus determination in lime and cement mortars

    Directory of Open Access Journals (Sweden)

    Rosell, J. R.

    2011-03-01

    Full Text Available The present work explains a simple method to determine the dynamic Young module (MOE by inducing a set of small mechanical perturbation to samples of lime and cement mortars and correlating the results obtained with results determined using other techniques and methods. The procedure described herein follows the instructions stated in the UNE-EN ISO 12680-1 standard for refractory products although in this study the instructions are applied to standardized RILEM 4x4x16 cm test samples made of lime and cement mortars. In addition, MOE determinations are obtained by using ultrasonic impulse velocity while static Young's modulus determinations are obtained by performing conventional bending tests. The ability of this procedure to correlate with results from other techniques, along with its simplicity, suggests that it can be widely adapted to determine the deformability of mortars under load using standardized samples.

    El presente trabajo muestra un método simple para determinar el módulo de Young dinámico (MOE a partir de pequeñas perturbaciones mecánicas producidas a probetas de mortero de cal y de cemento, correlacionando los resultados obtenidos con las correspondientes mediciones realizadas con otras técnicas. El procedimiento sigue básicamente las instrucciones fijadas en la norma UNE-EN ISO 12680-1 de productos refractarios, pero aplicándolo a probetas normalizadas RILEM 4x4x16 de morteros confeccionados con cal y cemento. Paralelamente se realizan determinaciones del MOE a partir de la velocidad de paso de impulsos ultrasónicos y determinaciones del módulo de Young estático a partir de ensayos de flexión convencionales. La simplicidad del método aplicado y la correlación de los resultados obtenidos con las variables medidas permiten concluir que esta metodología es de aplicación directa para determinar la deformabilidad bajo carga de los morteros a partir de probetas normalizadas.

  19. Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement Part 2. Mechanical strength of mortars and environmental impact.

    Science.gov (United States)

    Aubert, J E; Husson, B; Sarramone, N

    2007-07-19

    This second of two articles dealing with the utilization of MSWI fly ash in blended cement studies the effects of two variants of the stabilization process on the behavior of the treated fly ash (TFA) introduced into cement-based mortars. From a technological point of view, the modifications of the process are very efficient and eliminate the swelling produced by the introduction of MSWI fly ash in cement-based mortars. TFA has a significant activity in cement-based mortars and can also advantageously replace a part of the cement in cement-based material. From an environmental point of view, the results of traditional leaching tests on monolithic and crushed mortars highlight a poor stabilization of some harmful elements such as antimony and chromium. The use of a cement rich in ground granulated blast furnace slag (GGBFS) with a view to stabilizing the chromium is not efficient. Since neither adequate tests nor quality criteria exist to evaluate the pollutant potential of a waste with a view to reusing it, it is difficult to conclude on the environmental soundness of such a practice. Further experiments are necessary to investigate the environmental impact of TFA introduced in cement-based mortars depending on the reuse scenario.

  20. Coupling between mechanical behaviour and drying of cementing materials: experimental study on mortars

    International Nuclear Information System (INIS)

    The aim of this work is to understand the desiccation effects on the mechanical behaviour of cement materials. Two mortars of ratio E/C=0.5 and 0.8 have been tested. All the tests have been implemented after a six months maturing in water. The experimental study has been carried out as follows: 1)tests characterizing the differed behaviour and the transport properties have been carried out 2)tests characterizing the short term multiaxial mechanical behaviour have been carried out. The desiccation shrinkage in terms of the weight loss presents three characteristic phases. The permeability measurement on the mortar 05 shows that the permeability of the specimens dried and crept is greater than those of the specimens dried before being crept, and the permeability of the specimens submitted to a desiccation creep and then dried is sensibly the same as the last one in spite of a very important differed deformation. The influence of the desiccation on the uniaxial and deviatoric compressions resistance depends of the binding agent: for a cement paste of good quality (E/C=0.5), the resistances increase with the desiccation because of the capillary depression and of the hydric gradients. For a cement paste of low quality (E/C=0.8), there is a competitive effect between the increase of the microcracks induced and the specimen rigidification; the microcracking becomes then the parameter controlling the rupture process. The elasto-plastic behaviour becomes a damageable elasto-plastic behaviour during desiccation which induces, as the decrease of the E/C ratio, a translation of the elastic limit surfaces and ruptures towards higher stresses. In parallel, the elastic properties and the incompressibility modulus are damaged and the volume deformations increase after the drying. At last, the decrease of the Young modulus and the passage to the third shrinkage phase in terms of the weight loss coincide. This can be attributed to the induced microcracking: this decrease of the

  1. Low Carbon Footprint Mortar from Pozzolanic Waste Material

    Directory of Open Access Journals (Sweden)

    Taha Mehmannavaz

    2014-04-01

    Full Text Available Nowadays, Portland cement clinker leads to emission of CO2 into the atmosphere and therefore causes greenhouse effect. Incorporating of Palm Oil Fuel Ash (POFA and Pulverized Fuel Ash (PFA as partial cement replacement materials into mix of low carbon mortar decreases the amount of cement use and reduces high dependence on cements compared to ordinary mortar. The result of this research supported use of the new concept in preparing low carbon mortar for industrial constructions. Strength of low carbon mortar with POFA and PFA replacement in cement was affected and changed by replacing percent finesse, physical and chemical properties and pozzolanic activity of these wastes. Waste material replacement instead of Ordinary Portland Cement (OPC was used in this study. This in turn was useful for promoting better quality of construction and innovative systems in construction industry, especially in Malaysia. This study was surely a step forward to achieving quality products which were affordable, durable and environmentally friendly. Disposing ash contributes to shortage of landfill space in Malaysia. Besides, hazard of ash might be another serious issue for human health. The ash disposal area also might create a new problem, which is the area's sedimentation and erosion.

  2. The use of electrical impedance spectroscopy for monitoring the hydration products of Portland cement mortars with high percentage of pozzolans

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, J.M. [Departamento de Física Aplicada, Universitat Politècnica de València, Camino de Vera, 46022, Valencia (Spain); Fita, I.C., E-mail: infifer@fis.upv.es [Departamento de Física Aplicada, Universitat Politècnica de València, Camino de Vera, 46022, Valencia (Spain); Soriano, L.; Payá, J.; Borrachero, M.V. [ICITECH, Instituto de Ciencia y Tecnología del Hormigón, Universitat Politècnica de València (Spain)

    2013-08-15

    In this paper, mortars and pastes containing large replacement of pozzolan were studied by mechanical strength, thermogravimetric analysis (TGA), scanning electronic microscopy (SEM), mercury intrusion porosimetry (MIP) and electrical impedance spectroscopy (EIS). The effect of metakaolin (35%) and fly ash (60%) was evaluated and compared with an inert mineral addition (andalusite). The portlandite content was measured, finding that the pozzolanic reaction produced cementing systems with all portlandite fixed. The EIS measurements were analyzed by the equivalent electrical circuit (EEC) method. An EEC with three branches in parallel was applied. The dc resistance was related to the degree of hydration and allowed us to characterize plain and blended mortars. A constant phase element (CPE) quantified the electrical properties of the hydration products located in the solid–solution interface and was useful to distinguish the role of inert and pozzolanic admixtures present in the cement matrix.

  3. Influence of fly ash and its mean particle size on certain engineering properties of cement composite mortars

    Energy Technology Data Exchange (ETDEWEB)

    Gengying Li; Xiaozhong Wu [Shantou University, Shantou (China). Department of Civil Engineering

    2005-06-01

    An experimental investigation on the effects of incorporating large volumes of fly ash on the early engineering properties and long-term strength of masonry mortars is reported. The effect of fly ash and its mean particle size (PD) on the variation of workability and strength has been studied. It was found that fly ash and its mean particle size play a very significant role on the strength of masonry mortars. It has been observed that the early-term strength, except the mortars incorporating coarse fly ash (CFA), was slightly influenced by the replacement with fly ash. The long-term strength (both the bond strength and the compressive strength) will significantly increase, especially for the bond strength of mortars incorporating coarse fly ash. It was also found that the bond strength significantly increased as the mean particle size of fly ash decreases after 28 days curing. However, the 7-day strength was little influenced by fly ash particle size. The fluidity of composite mortar enhanced due to replace cement and lime with fly ash, and the mean PD of fly ash significantly influenced the workability.

  4. The use of electrical impedance spectroscopy for monitoring the hydration products of Portland cement mortars with high percentage of pozzolans

    OpenAIRE

    Cruz González, José Mª; Fita Fernández, Inmaculada Concepción; Soriano Martinez, Lourdes; Paya Bernabeu, Jorge Juan; Borrachero Rosado, María Victoria

    2013-01-01

    In this paper, mortars and pastes containing large replacement of pozzolan were studied by mechanical strength, thermogravimetric analysis (TGA), scanning electronic microscopy (SEM), mercury intrusion porosimetry (MIP) and electrical impedance spectroscopy (EIS). The effect of metakaolin (35%) and fly ash (60%) was evaluated and compared with an inert mineral addition (andalusite). The portlandite content was measured, finding that the pozzolanic reaction produced cementing systems with all ...

  5. Properties and structure of cement mortar modified with epoxy emulsion%环氧树脂乳液改性水泥砂浆性能与结构

    Institute of Scientific and Technical Information of China (English)

    章凯

    2012-01-01

    The mechanical and adhesive properties, shrinkage and durability of cement mortar modified with water borne epoxy emulsion were experimentally studied, and the microstructures of the mortars were analyzed by SEM and MIP. The results showed that, adding 6%~10% (solid content) epoxy emulsion based on the mass of the cement in mortar will remarkably improve the mechanical properties of the mortar, and the adhesive strength of the mortar with aged cement mortar. The drying shrinkage of the modified mortar decreased, and the chloride permeability,carbonation and frost resistance increased with the increase of the polymer amount added. Compared with ordinary cement mortar, the polymer modified cement mortar is more compacted in structure,lower in porosity and small in mean pore size.%研究了水性环氧树脂乳液改性水泥砂浆的力学性能、粘结性能、收缩性能和耐久性能,用SEM和MIP分析了砂浆的结构.结果表明,掺加6%~10%水性环氧树脂乳液可有效提高水泥基修补砂浆的力学性能和与老砂浆的粘结强度,降低水泥砂浆的收缩值;水泥砂浆的抗渗性、抗碳化性以及抗冻性能均随水性环氧树脂掺量的增加而显著提高;较之未经改性的普通砂浆,水性环氧树脂乳液改性水泥砂浆的结构更为致密,连通孔的孔隙率和平均孔径小.

  6. Behaviour of alkaline cement mortars reinforced with acrylic and polypropylene fibres

    Directory of Open Access Journals (Sweden)

    Puertas, P.

    2000-09-01

    Full Text Available In the present work, the behaviour of alkaline cement mortars reinforced with fibres of different nature (acrylic and polypropylene fibres is studied. Also the chemical stability of those fibres in strong alkaline medium has been investigated. Three different matrixes have been used: glass blast furnace slag activated with NaOH 2M (room temperature, 22 ºC; fly ash activated with NaOH 8M, cured at 85ºC during 24 hours and 50% fly ash / 50% slag activated with NaOH 8M, room temperature. The fibre content was 0,2 and 1% in mortar volume. The tests carried out were: tenacity and tenacity index, impact resistance and drying shrinkage. On the specimens tested, a microstructural study by SEM/EDX was carried out. The results obtained have demonstrated the following: a The acrylic and polypropylene fibres are stable in strong basic media, although the first undergo hydrolysis/ hydration processes showed by the alteration of the surface texture, b with low fibre contents (0,2% in volume, tenacity and tenacity index of these mortars remain unaffected. With higher contents (1%, an increase of the corresponding values is produced. This increment is higher in mortars with alkaline activated slag, c For the three matrixes studied, the polypropylene fibres increase the impact strength in higher degree than the acrylic ones. The reinforcement effect is more significative in matrix A and when the fibre content is 1% in volume, d the shrinkage of these mortars is modified depending on the matrix and fibre type. In mortars of activated slag, fibres do not reduce the shrinkage. In mortars of activated fly ash reinforced with acrylic fibres, shrinkage is lower than those containing polypropylene fibres are. Finally, in mortars of fly ash/ activated slag, the two fibres decrease the drying shrinkage.

    En el presente trabajo se estudia el comportamiento de morteros de cementos alcalinos reforzados con fibras de distinta naturaleza (acrílica y de polipropileno

  7. Composite cement mortars based on marine sediments and oyster shell powder

    Directory of Open Access Journals (Sweden)

    Ez-zaki, H.

    2016-03-01

    Full Text Available Additions of dredged marine sediments and oyster shell powder (OS as cement substitute materials in mortars are examined by several techniques. The sediments have high water and chloride contents and calcite, quartz, illite and kaolinite as principal minerals. The OS powders are entirely composed of calcium carbonate and traces of other impurities. Four mixtures of treated sediments and OS powders at 650 °C and 850 °C are added to Portland cement at 8%, 16% and 33% by weight. The hydration of composite pastes is followed by calorimetric tests, the porosity accessible to water, the bulk density, the permeability to gas, the compressive strength and the accelerated carbonation resistance are measured. In general, the increase of addition amounts reduced the performance of mortars. However, a reduction of gas permeability was observed when the addition was up to 33%. Around 16% of addition, the compressive strength and carbonation resistance were improved.En este trabajo se ha valorado la sustitución de cemento en morteros por sedimentos marinos dragados y polvo de concha de ostra (OS. Los sedimentos tienen altos contenidos de agua, cloruros, calcita, cuarzo, illita y caolinita como minerales principales. Los polvos OS están compuestos de carbonato cálcico y trazas de otras impurezas. Se añadieron a un cemento Portland, cuatro mezclas de los sedimentos y polvos de OS tratados a 650 °C y 850 °C en proporciones del 8%, 16% y 33% en peso. La hidratación de pastas se estudió a través de calorimetría. Se estudió además la porosidad accesible al agua, densidad aparente, permeabilidad al gas, resistencia a compresión y carbonatación acelerada. En general, un aumento en la adición produjo una reducción del rendimiento de los morteros. Se observó, sin embargo, una reducción de la permeabilidad a los gases con porcentajes de adición de hasta el 33%. Con valores del 16% de sustitución, mejoraron las resistencias mecánicas y la

  8. Properties of Chemically Combusted Calcium Carbide Residue and Its Influence on Cement Properties

    Directory of Open Access Journals (Sweden)

    Hongfang Sun

    2015-02-01

    Full Text Available Calcium carbide residue (CCR is a waste by-product from acetylene gas production. The main component of CCR is Ca(OH2, which can react with siliceous materials through pozzolanic reactions, resulting in a product similar to those obtained from the cement hydration process. Thus, it is possible to use CCR as a substitute for Portland cement in concrete. In this research, we synthesized CCR and silica fume through a chemical combustion technique to produce a new reactive cementitious powder (RCP. The properties of paste and mortar in fresh and hardened states (setting time, shrinkage, and compressive strength with 5% cement replacement by RCP were evaluated. The hydration of RCP and OPC (Ordinary Portland Cement pastes was also examined through SEM (scanning electron microscope. Test results showed that in comparison to control OPC mix, the hydration products for the RCP mix took longer to formulate. The initial and final setting times were prolonged, while the drying shrinkage was significantly reduced. The compressive strength at the age of 45 days for RCP mortar mix was found to be higher than that of OPC mortar and OPC mortar with silica fume mix by 10% and 8%, respectively. Therefore, the synthesized RCP was proved to be a sustainable active cementitious powder for the strength enhanced of building materials, which will result in the diversion of significant quantities of this by-product from landfills.

  9. Study on Strength of Innovative Mortar Synthesis with Epoxy Resin, Fly Ash and Quarry Dust

    Directory of Open Access Journals (Sweden)

    P. Sudheer

    2016-06-01

    Full Text Available Generally, mortar is a uniform combination of Fine aggregate and cement. In this study an innovative concept adopts to synthesis a hybrid mortar with Epoxy resin, Fly ash and quarry dust which are replacing the fine aggregate and cement. The alternative materials are preferably waste products such as quarry dust and fly ash in order to moderate the cost of mortar. The main objective of this work is to study the compressive strength of mortar cubes by various combinations of cement and fine aggregate replaced by Epoxy resin, fly ash, and quarry dust at the age of 7 days. The results of mortarmade with cement replaced with 20%, 25%, and 30% (w/w of Epoxy resin, and fine aggregate replaced by (0% QD - 100% FA (100% QD - 0% FA and (70% QD - 30% FA of quarry dust and fly ash were compared with conventional mortar cubes. It was observed that all mortar cubes made with Epoxy resin, fly ash, and quarry dust had found to have a compressive strength of more than 150% when compared to compressive strength with normal cement of OPC53 grade at the age of 7 days (Approx.35.5Mpa

  10. Changes in Properties of Cement and Lime Mortars When Incorporating Fibers from End-of-Life Tires

    Directory of Open Access Journals (Sweden)

    Lluís Gil

    2016-02-01

    Full Text Available This paper studies the addition of fibers from end-of-life tires to commercial mortar mixtures. Two different types of mortar, one lime-plastic and other cement-fluid, are mixed with different percentage of fibers ranging from 0% to 1%. The changes in bulk density, consistency, compressive and flexural strength, dynamic Young modulus and water absorption are studied. According to the results, consistency is the property that shows more relevant changes for an addition of 0.25% fibers. Consistency is related to workability and affects the water absorption and the Young modulus values. On the contrary, bulk density and mechanical properties did not change with the addition of fibers. The results prove that this fiber, considered a waste from recycling of end-of-life tires, can be used in commercial mixtures without losing strength. On the other hand, mortar workability limits the amount of fibers that can be included in the mixture and this parameter determines the performance of the mortar.

  11. Mechanism of Expansion of Mortars with Limestone Filler due to External Sulfate Attack

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mechanism of expansion of mortars and pastes with limestone filler due to external sulfate attack was studied.Mortars and pastes made at water to solid ratios of 0.45, 0.5, 0.6 from Portland Cement (OPC) with 0%, 20% or 30% (w/w) limestone filler (LF) were cured in a 95±1% RH moist room at 20±1 ℃ for 14 or 28 days. They subsequently were immersed in 5% Na2SO4(0.35 M) solution at ambient temperature (1~35 ℃). The expansion of the specimens was measured every month, and selected samples were examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results indicate that mortars with 20% LF show larger expansion than that of OPC mortars at up to 9 months of exposure,and the amount of gypsum in both mortars and pastes with LF is much more than that in mortars and pastes without LF. Therefore, it is reasonable to conclude that the formation of massive gypsum leads to the lager expansion of the mortars and pastes containing 20% LF. These behaviors may be explained by the changes in hydration products due to the addition of LF.

  12. Influence of free water content on the compressive mechanical behaviour of cement mortar under high strain rate

    Indian Academy of Sciences (India)

    Jikai Zhou; Xudong Chen; Longqiang Wu; Xiaowei Kan

    2011-06-01

    The effect of free water content upon the compressive mechanical behaviour of cement mortar under high loading rate was studied. The uniaxial rapid compressive loading testing of a total of 30 specimens, nominally 37 mm in diameter and 18.5 mm in height, with five different saturations (0%, 25%, 50%, 75% and 100%, respectively) were executed in this paper. The technique ‘Split Hopkinson pressure bar’ (SHPB) was used. The impact velocity was 10 m/s with the corresponding strain rate as 102/s. Water-cement ratio of 0.5 was used. The compressive behaviour of the materials was measured in terms of the maximum stress, Young’s modulus, critical strain at maximum stress and ultimate strain at failure. The data obtained from test indicates that the similarity exists in the shape of strain–stress curves of cement mortars with different water content, the upward section of the stress–strain curve shows bilinear characteristics, while the descending stage (softening state) is almost linear. The dynamic compressive strength of cement mortar increased with the decreasing of water content, the dynamic compressive strength of the saturated specimens was 23% lower than that of the totally dry specimens. With an increase in water content, the Young’s modulus first increases and then decreases, the Young’s modulus of the saturated specimens was 23% lower than that of the totally dry specimens. No significant changes occurred in the critical and ultimate strain value as the water content is changed.

  13. Influence of clinker grinding-aids on the intrinsic characteristics of cements and on the behaviour of mortars

    Directory of Open Access Journals (Sweden)

    Fernández Luco, L.

    2003-12-01

    Full Text Available In the production of portland cement, grinding aids are used to improve the grinding stage and reduce the energy required to achieve the required fineness. These additives remain in the final product and they might influence the characteristics and properties of the cement, and thus, mortar and concrete. This paper presents an evaluation of two grinding-aid additives used in the production of portland cement ground in a ball mill at a laboratory stage, with suitable proportions of portland cement clinker and gypsum. A control cement mix was also produced without using any admixture and the results are shown on a comparative basis. Conclusions indicate that grinding-aids additives have some influence on the characteristics of portland cement produced, increasing their specific surface and modifying microstructure and its packing ability. Mortars and concretes made with cements ground with the addition of gringing-aids exhibit higher strength at any age and a reduced water demand. Special attention should be taken to consider any interaction with water-reducing admixture in concretes and mortars.

    En la fabricación de cemento portland es una práctica creciente la utilización de aditivos para optimizar el proceso de molienda; éstos quedan incorporados en el producto final y pueden influir sobre las características y propiedades del cemento, morteros y hormigones. En este trabajo se presenta la evaluación de dos aditivos comerciales en la molienda conjunta de clínker de cemento portland y yeso comercial, tratados en un molino a bolas a escala de laboratorio, en forma comparativa con un cemento sin aditivo producido en forma equivalente. Las conclusiones indican que los aditivos de molienda tienen influencia en las características del cemento resultante, incrementando su superficie y modificando su microestructura y estado de agregación; los morteros mejoran sus prestaciones mecánicas a todas las edades y se reduce la demanda de agua

  14. Effect of high doses of chemical admixtures on the strength development and freeze-thaw durability of portland cement mortar

    Science.gov (United States)

    Korhonen, Charles J.

    This thesis examines the low-temperature strength development of portland cement concrete made with high doses of chemical admixtures dissolved in the mixing water and the possible beneficial effect of these admixtures on that concrete's long-term freeze-thaw durability. The literature shows that high doses of chemical admixtures can protect fresh concrete against freezing and that, under certain conditions, these admixtures can enhance the freeze-thaw durability of concrete. The challenge is that there are no acceptance standards in the U.S. that allow chemicals to be used to protect concrete against freezing. Also, the perception is that chemicals might somehow harm the concrete. This perception seems to be based on the fact that deicing salts, when applied to concrete pavement, cause roadways to scale away. This study investigated the effect of high doses of commercially available admixtures on fresh concrete while it gained strength at low temperature and on hardened concrete exposed to repeated cycles of freezing and thawing in a moist environment. The reason for studying off-the-shelf admixtures was that these materials are approved for use in concrete; they were already governed by their own set of standards. Four mortars were examined, each with a different cement and water content, when dosed with five commercial admixtures. This allowed the fresh mortar to gain appreciable strength when it was kept at nearly -10C. The admixtures also enhanced the freeze-thaw durability of the mortar, even when it was not air-entrained. Clearly, as the dosage of admixture increased beyond approximately 22% by weight of water, the mortar appeared to be unaffected by up to 700 cycles of freezing and thawing.

  15. Influence of supplementary cementitious materials on water transport kinetics and mechanical properties of hydrated lime and cement mortars

    Directory of Open Access Journals (Sweden)

    Ince, C.

    2015-06-01

    Full Text Available The purpose of this paper is an investigation of the possible role of supplementary cementitious materials (SCMs on water transport kinetics and mechanical properties of hydrated lime (CL90 and Portland cement (PC mortars. The properties of hydrated lime are significantly different from those of cement and therefore modifying fresh and hardened properties of these mortars are vital for mortar/substrate optimisation in masonry construction. The parameters investigated in this paper often are the main barriers to the use of hydrated lime in construction practice. The results show that transfer sorptivity and time to dewater freshly-mixed hydrated lime mortars can be modified when binder is partially replaced with SCMs. Compressive strength of CL90 mortars is increased systematically with the increased replacement levels of SCMs and the results are supported with the microstructural images. The ability to modify the water transport kinetics and mechanical properties allows compatibility between the mortar and the substrate unit in masonry construction.El objetivo de este artículo es investigar el papel de los materiales cementantes suplementarios (SCMs en la cinética de transporte del agua y en las propiedades mecánicas de los morteros de cal hidratada (CL90 y cemento Portland. Las propiedades de la cal hidratada son significativamente diferentes a las del cemento y por lo tanto el control de las propiedades de los morteros frescos y endurecidos es fundamental en la optimización mortero/substrato en albañilería. Los parámetros estudiados en este trabajo son a menudo las principales barreras para el uso de la cal hidratada en la práctica de la construcción. Los resultados indican que la absortividad y el tiempo necesario para deshidratar morteros de cal hidratada recién mezclados pueden ser controlados cuando el conglomerante es parcialmente remplazado por SCMs. La resistencia a compresión de los morteros CL90 aumenta sistem

  16. Engineering properties of cement mortar with pond ash in South Korea as construction materials: from waste to concrete

    Science.gov (United States)

    Jung, Sang; Kwon, Seung-Jun

    2013-09-01

    Among the wastes from coal combustion product, only fly ash is widely used for mineral mixture in concrete for its various advantages. However the other wastes including bottom ash, so called PA (pond ash) are limitedly reused for reclamation. In this paper, the engineering properties of domestic pond ash which has been used for reclamation are experimentally studied. For this, two reclamation sites (DH and TA) in South Korea are selected, and two domestic PAs are obtained. Cement mortar with two different w/c (water to cement) ratios and 3 different replacement ratios (0%, 30%, and 60%) of sand are prepared for the tests. For workability and physical properties of PA cement mortar, several tests like flow, setting time, and compressive strength are evaluated. Several durability tests including porosity measuring, freezing and thawing, chloride migration, and accelerated carbonation are also performed. Through the tests, PA (especially from DH area) in surface saturated condition is evaluated to have internal curing action which leads to reasonable strength development and durability performances. The results show a potential applicability of PA to concrete aggregate, which can reduce consuming natural resources and lead to active reutilization of coal product waste.

  17. Studies on potential of Portland cement mortar for binding of waterworks sludge to reduce heavy metal leaching

    Indian Academy of Sciences (India)

    PARAMALINGGAM THANALECHUMI; ABDULL RAHIM MOHD YUSOFF; MOHANADOSS PONRAJ; HANIM AWAB

    2016-03-01

    The investigation of heavy metal leaching and physicochemical properties of cement-solidified waterworks sludge (CMWWS) formed by incorporating waterworks sludge (WWS) into cement mortar was carried out. The chemical composition, compressive strength and other physicochemical properties of the CMWWS cube specimens were determined using field emission scanning electron microscopy (FESEM), X-ray diffractometry (XRD) and Fourier transform-infrared spectroscopy (FTIR). The major type of chemical components present in CMWWS was found to be Al and Fe. The increasing amount of WWS added to cement mortar resulted in the increasing of organic matter, urchin-like morphology and clear peak intensity. At the end of 28 days of curing, the soaking solution became strongly basic and CMWWS cube specimens leached out higher amount of heavy metals. The compressive strength of CMWWS increased up to a WWS percentage of 10%, and basic (pH [ 7) curing solution was found to be better than water for curing purposes. It is concluded that solidification–stabilisation (S/S) technique is able to effectively reduce the leaching of heavy metals from the WWS and CMWWS containing up to 10% WWS can be used as construction material.

  18. Effect of nano-Si2O and nano-Al2O3 on cement mortars for use in agriculture and livestock production

    OpenAIRE

    León Brito, Nestor; Massana Guitart, Jordi; Alonso Peralta, Francisco; Moragues Terrades, Amparo; Sanchez Espinosa, Elvira

    2014-01-01

    The effect of nano-silica, nano-alumina and binary combinations on surface hardness, resistance to abrasion and freeze-thaw cycle resistance in cement mortars was investigated. The Vickers hardness, the Los Angeles coefficient (LA) and the loss of mass in each of the freeze–thaw cycles to which the samples were subjected were measured. Four cement mortars CEM I 52.5R were prepared, one as control, and the other three with the additions: 5% nano-Si, 5% nano-Al and mix 2.5% n-Si and 2.5% n-Al. ...

  19. Effect of kaolin treatment temperature on mortar chloride permeability

    Directory of Open Access Journals (Sweden)

    Puertas, F.

    2007-03-01

    Full Text Available The present paper discusses the results of chloride resistance tests conducted on ordinary Portland cement (OPC mortars containing a Colombian kaolin pre-treated at temperatures of from 600 to 800 ºC. The resulting metakaolin (MK was added to OPC mortar mixes in proportions of 10 and 20% by cement weight. The mortars were compared for physical and chemical properties, including capillary absorption, chloride permeability and pore microstructure as assessed by mercury porosimetry. The best performance was recorded for the samples containing 20% of the material treated at 800 ºC.En el presente trabajo se incluyen los resultados de la resistencia a la penetración de cloruros de morteros de Cemento Portland Ordinario (OPC adicionados con un caolín colombiano sometido a tratamiento térmico en un rango de temperaturas entre 600 y 800 °C. Los productos del tratamiento térmico, metacaolín (MK, son incorporados en mezclas de morteros de OPC en proporciones del 10 y 20% en relación al peso del cemento. Se comparan sus características físico-químicas, entre las cuales se incluye la microestructura de poros evaluada por la técnica de porosimetría de mercurio, con la absorción capilar y la permeabilidad a cloruros. Se concluye que las muestras adicionadas con un 20% del material tratado térmicamente a 800 °C presentan el mejor desempeño en sus propiedades finales.

  20. [Microbial settlement of paint- and building-materials in the sphere of drinking water. 9. Communication: experimental examination of cement mortar for the lining with tiles (author's transl)].

    Science.gov (United States)

    Schoenen, D; Thofern, E

    1981-12-01

    The observation of a microbial growth in form of macrocolonies upon the joints of a tiled drinking water reservoir caused the microbiological testing of different pure mineral and some plastic containing cement mortar. Besides the conditions allowing the growth of macrocolonies on tiled plates with a construction like in a reservoir were examined.

  1. Corrosion rate of steel embedded in blended Portland and fluid catalytic cracking catalyst residue (FC3R cement mortars

    Directory of Open Access Journals (Sweden)

    Payá, J.

    2008-12-01

    Full Text Available This paper reports on a study of the corrosion levels in steel bars embedded in mortars made with a blend of Portland cement and (0-20% spent fluid catalytic cracking catalyst residue (FC3R, with a variable (0.3-0.7 water/binder (w/b ratio. The specimens were stored in the following conditions: relative humidity of 40, 80 or 100% and CO2 concentrations of 5 and 100%. The steel corrosion rate was measured with polarization resistance techniques. In the absence of aggressive agents, the steel was found to remain duly passivated in mortars with an FC3R content of up to 15% under all the conditions of relative humidity tested. The reinforcement corrosion level in mortars with a w/b ratio of 0.3 and 15% FC3R subjected to accelerated carbonation was similar to the level observed in the unblended Portland cement control mortar.En este trabajo se ha estudiado el nivel de corrosión de barras de acero embebidas en morteros de cemento Portland con relación agua/material cementante (a/mc variable (0,3-0,7, en los que parte del cemento (0-20% se sustituyó por catalizador de craqueo usado (FC3R. Las condiciones de conservación de las probetas elaboradas fueron las siguientes: distintas humedades relativas (40, 80 y 100% y dos concentraciones de CO2 (5 y 100%. La velocidad de corrosión de los aceros se midió mediante la técnica de resistencia de polarización. Se ha podido determinar que, bajo las distintas condiciones de humedad relativa y ausencia de agresivo, los aceros se mantuvieron correctamente pasivados en los morteros con contenidos de FC3R de hasta el 15%. El nivel de corrosión que presenta el refuerzo embebidos en morteros con sustitución de un 15% de cemento por FC3R y relación a/mc 0,3, al ser sometidos a un proceso de carbonatación acelerada, era muy similar al mostrado por el mortero patrón, sin FC3R.

  2. Use of Stone Dust & Granite Powder as a Partial Replacement of Cement

    Directory of Open Access Journals (Sweden)

    Prerit Saxena

    2016-06-01

    Full Text Available The research demonstrate the use of naturally available waste material as a partial replacement of OPC cement resulting in improving the compressive strength of cement. Since cement manufacturing process involves emission of CO2 to a considerable amount in the environment resulting in global warming, thus use of these partial substituents in cement reduces this ill effect making an environment free construction. The objective of this thesis is to find optimum percentage up to which these pozzolanic waste materials can replace OPC-43 grade cement to obtain maximum compressive strength. In this thesis OPC-43 grade cement is replaced partially by stone dust & granite powder simultaneously in the proportion of 5%, 10%, 15% & 20% by weight. Mortar cubes were casted, tested and compared in terms of compressive strength to the standard mortar mixtures. Cubes were subjected to compressive strength test to determine strength at 7 days, 28 days & 56 days. The result obtained clearly represents that on partial replacement of cement by 5% with stone dust, compressive strength obtained is maximum. On the other hand, higher strength is obtained when cement is replaced with 10% granite powder

  3. Effect of sewage sludge ash (SSA on the mechanical performance and corrosion levels of reinforced Portland cement mortars

    Directory of Open Access Journals (Sweden)

    Andión, L. G.ª

    2006-06-01

    Full Text Available The article describes a study conducted to determinecorrosion in reinforcement embedded in Portland cement(PC mortars with different percentages of sewage sludgeash (SSA admixtures. The polarization resistancetechnique was used to determine the steel corrosion rate(Icorr in the test specimens. The samples were subjectedto different environmental conditions and aggressiveagents: 100% relative humidity (RH, accelerated carbonationat 70% RH and seawater immersion. Portlandcement was partially substituted for SSA in the mixes atrates of 0, 10, 20, 30 and 60% (by mass to make thedifferent mortars. The results show that where cementwas replaced by SSA at rates of up to 10% by mass,mortar corrosion performance was comparable to thebehaviour observed in SSA-free mortars (control mortar:0% SSA. Data for higher rates are also shown. From themechanical standpoint, SSA exhibited moderate pozzolanicactivity and the best performance when SSA wasadded at a rate of 10% to mixes with a water/(binder:PC + SSA (w/b ratio of 0.5.Se ha estudiado el nivel de corrosion que presentan lasarmaduras embebidas en morteros fabricados con cementoPortland (CP con diferentes porcentajes de sustitucion deceniza de lodo de depuradora (CLD. Se ha utilizado la tecnicade la Resistencia a la Polarizacion para determinar lavelocidad de corrosion del acero embebido en las muestrasestudiadas. Las muestras se han sometido a diferentes condicionesambientales y agentes agresivos: 100% de humedadrelativa (HR, carbonatacion acelerada al 70% HR einmersion en agua de mar. Para la fabricacion de los distintosmorteros, el cemento Portland ha sido parcialmente sustituidopor CLD en los siguientes porcentajes en masa: 0,10, 20, 30 y 60%. Los resultados muestran que sustitucionesde cemento por CLD de hasta el 10% en masa no alteranel comportamiento frente a la corrosion de los morterosal compararlos con los morteros libres de CLD (morteroscontrol: 0% de sustitucion de cemento por CLD. Se

  4. Mechanism and Preventive Technology of the Thaumasite Form of Sulfate Attack on Cement Mortars

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The deterioration mechanism of thaumasite towards cement or concrete structure and the deterioration pattern of in-situ construction caused by the formation of thaumasite were studied in this paper. To improve the TSA (the thaumasite form of sulfate attack) resistance, the cement type, water to cement ratios, the mineral admixture and the circumstance factors should be taken into consideration.

  5. Effect of mineral additives (natural pozzolana and sand of dunes) by substitution of cement on the performance and durability of mortars

    Science.gov (United States)

    Saidi, M.; Safi, B.

    2016-04-01

    The objective of our work consists of the study of the substitution effects of clinker by mineral additions such as: natural pozzolana (PZ) and the sand of dunes (SD) finely crushed on the mechanical properties and the durability of the mortars worked out according to various combinations containing these additions. The results from this research confirm that the substitution of 20% to 30% of cement APC (Artificial Portland Cement) by additions in binary cement (APC + PZ) or ternary (APC + PZ + SD) contributes positively to the mechanical strength of mortars and resistance to the chemical attacks in various corrosive conditions such as: hydrochloric acid, sulfuric acid and nitric acid. The mechanical strength of the different variants is comparable to those of the APC. The test results of the weight loss and phenolphthalein shows that the chemical resistance of variants (PZ20) and (PZ20 with SD5) are larger compared to the reference mortar APC and other variants. This study shows that adding value by substituting a part of clinker. This substitution can save 20% to 30% of clinker used for the manufacture of cement; this will have a beneficial effect for cement and economically (less energy spent for the clinker burning). This study contributes to the protection of the environment as to produce one ton of clinker generates about one ton of CO2 is harmful to the atmosphere. Based on our results we will reduce from 20% to 30% CO2 gas responsible for the greenhouse effect.

  6. Influence on the physical-mechanical properties of portland-cement mortar, have admixtures of colophony and tannin

    Directory of Open Access Journals (Sweden)

    Fernández Cánovas, M.

    1989-12-01

    Full Text Available The colophony has been used as an admixture in the Portland cement mortar with the intention to observe its influence on the air content, water absorption, adhesive capacity and mechanical properties. The results obtained have shown that, the colophony acts as air entrainment, reduces the permeability and improves the adhesion between the past and aggregates. Likewise, the addition of tannin and montan wax to the colophony has the efect of reducing the formation of foam and improves the impermeability of the mortar.

    Se ha empleado la colofonia como aditivo en el mortero de cemento portland con el fin de observar su influencia sobre el contenido de aire, absorción de agua, capacidad adhesiva y propiedades mecánicas. Los resultados obtenidos han puesto de manifiesto que la colofonia actúa como aireante, aumenta la impermeabilidad y mejora la adherencia de la pasta al árido. Asimismo, la adición de tanino y cera montana a la colofonia tiene el efecto de reducir la formación de espuma y mejorar también la impermeabilidad del mortero.

  7. Mechanism and Test of Mineral Admixture Filling in Cement Mortar%矿物掺合料在水泥砂浆中的填充机理及试验研究

    Institute of Scientific and Technical Information of China (English)

    李滢

    2013-01-01

    主要讨论了矿物掺合料在水泥砂浆中的填充机理,并且以粉煤灰、矿渣粉及硅灰单一组分、复合组分考察其对水泥胶砂强度及微观结构的影响.研究表明,不同细度的矿物掺合料掺入到水泥浆体中后,可以优化粉体的次级颗粒级配,提高密实度.从而表现出水泥砂浆的强度得到提高,微观结构趋于密实.%Filling mechanism of mineral admixture in cement mortar was discussed,with fly ash,superfine slag powder,silica fume and their compounds filling into cement mortar to study their influence on the strength and microstructure of cement mortar.It is demonstrated that the different mineral admixtures can improve the secondary particles size distribution of cementations materials,and then improve the density of cement mortar.So the strength of cement mortar increased and the microstructure of cement mortar get denser.

  8. Steel passive state stability in activated fly ash mortars

    Directory of Open Access Journals (Sweden)

    Fernández-Jiménez, A.

    2010-12-01

    Full Text Available The present study explores the behaviour of structural steel embedded in Portland cement (OPC mortars and NaOH- and NaOH-waterglass-activated fly ash, in the presence and absence of 2 % Cl- (CaCl2. Variations were determined in the corrosion potential (Ecorr, linear polarization resistance (Rp and corrosion current density (icorr under different environmental conditions (90 days at 95 % relative humidity (RH, 30 days at ≈ 30 % RH, 760 days at ≈ 95 % RH. In the absence of Cl-, fly ash mortars were able to passivate steel reinforcement, although the stability of the passive state in changing environmental conditions was found to depend heavily on the activating solution used. Steel corrosion in the presence of 2 % Cl- was observed to be similar to the corrosion reported for the material in OPC mortars.

    En el presente trabajo se estudia el comportamiento del acero estructural embebido en morteros de cemento Pórtland (OPC y de cenizas volantes activadas con NaOH y una mezcla de NaOH y waterglass, en ausencia y en presencia de un 2% de Cl- (CaCl2. Se determino la evolución del potencial de corrosión (Ecorr, la resistencia de polarización lineal (Rp y la intensidad de corrosión (icorr, variando las condiciones ambientales (90 días al 95% de humedad relativa (HR-30 días a ≈ 30% HR- 760 días a ≈ 95% HR. En ausencia de Cl- los morteros de cenizas volantes activadas pueden pasivar los refuerzos de acero, si bien la estabilidad del estado pasivo ante cambios en las condiciones ambientales parece mostrar una fuerte dependencia de la solución activadora empleada. En presencia de un 2% de Cl- los aceros se corroen mostrando en comportamiento similar al observado en morteros en base OPC.

  9. The Effect Of Pozzolan Surface Properties On Physical And Mechanical Properties Of Cement Mortars

    OpenAIRE

    KOÇAK, YILMAZ; DORUM, Atila; Bülent YILMAZ; UCAR, Ali

    2010-01-01

    This study aims to determine mutual influence on blast furnace slag, fly ash and cement with added trass with Portland cement. For this purpose, physical, chemical, XRD, FT-IR, zeta (electrokinetic) potential and standard cement tests were applied to materials. In this study, it is shown that physical characteristics of pozzolan mostly depend on their molecular structures. Properties of molecular structure, in addition to its chrystal and amorphous character, change based on the existence of ...

  10. Evaluation of the properties of bitumen and cement pastes and mortars used in the immobilization of waste radioactive

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Vanessa Mota; de Tello, Cledola Cassia Oliveira, E-mail: vanessamotavieira@gmail.com, E-mail: tellocc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The Project RBMN was launched in November 2008 and aims to establish, manage and execute all tasks for implementing the Brazilian Repository, from its conception to its construction. The concept to be adopted will be a near-surface repository. The inventory includes wastes from the operation of nuclear power plants, fuel cycle facilities and from the use of radionuclides in medicine, industry and activities research and development. The implementation of the national repository is an important technical requirement, and a legal requirement for the entry into operation of the nuclear power plant Angra 3. In Brazil, for the immobilization and solidification of radioactive waste of low and intermediate level of radiation from NPPs are used cement, in Angra 1, and bitumen, in Angra 2. Studies indicate serious concerns about the risks associated with bituminization radioactive waste, much related to the process as the product. There are two major problems due to the presence of products bituminization in repositories, swelling of the waste products and their degradation in the long term. To accommodate the swelling, filling the drums must be limited to 70 - 90% of its volume, which reduces the structural stability of the repository and the optimization of deposition. This study aims to evaluate of the properties of bitumen and cement pastes and mortars used in the immobilization of waste radioactive. (author)

  11. [Microbial settlement of paint- and building-materials in the sphere of drinking water. 5. Communication: Macrocolonies on the cement mortar lining in a water main (author's transl)].

    Science.gov (United States)

    Schoenen, D

    1980-09-01

    It is reported a microbial growth in form of macrocolonies on a cement mortar line in a potable water main. Simultaneously an increase of bacterial content in the water could be observed. The bacterial content could be reduced by chlorination, but the microbial growth on the surface of the lining was not suppressed. Macrocolonies could be observed the same as before at the last inspection 6 1/2 years after opening of the main.

  12. The effect of pozzolan additions on the shrinkage of cement pastes and mortars during their first hours of age

    Directory of Open Access Journals (Sweden)

    Ossa, M. Mauricio

    1992-03-01

    Full Text Available The traditional favour enjoyed by cement including additions and by their diverse uses in Chile calls for an extense investigation of their behaviour in order that the results may justify their utilization in specific projects. This works studies volume changes occurring in cement pastes and mortars containing pozzolan additions during their first hours of age. This investigation used cements made in the laboratory from raw materials supplied by chilean manufacturers. Two types of clinkers were used, namely; a gypsum type and a natural pozzolan type, added in proportions ranging from 0 to 30%.Tests were conducted to ascertain the shrinkage of cement pastes and mortars since the first moments following their mixing operation, employing there for moulds fitted with a special device designed and implemented at the laboratory of the IDIEM Department of Agglomerants. The results thus gathered corroborated the fact that independently of cement characteristics, in general the deformation of pastes and mortars exhibits successive periods of first shrinkage swelling, and second shrinkage. The first shrinkage is affected by the ambient conditions of humidity, temperature, and wind (evaporation, but also in a preponderant way by cement specific surface, which allows higher velocity in the chemical reactions occurring during that period. Moreover the compactation degree is also affecting shrinkage, here. On the other hand, it was confirmed that with cements of like fineness, those having higher C3A contents exhibit an overall shrinkage larger than that of cements having low contents. At last it was possible to ascertain that an increase in pozzolan contents does not affect shrinkage directly, but that its presence may eventually modify the gypsum/clinker ratio and thus give rise to changes, specially in the two States of swelling and second shrinkage.

    La tradicional aceptación en Chile de los cementos con adición y su diversidad

  13. Effects of GH Admixture on the Early Strength of Fly Ash Concrete and Mortar

    Institute of Scientific and Technical Information of China (English)

    KANG Jingfu; WANG Xiufen

    2008-01-01

    The enhancement effects of GH admixture on the early strengths of fly ash concrete and mortar were studied, and the mechanism was analyzed by X-ray diffraction (XRD) and scanning electro microscope (SEM). Experimental results show that, by the incorporation of GH admixture, both of cement hydration and pozzolanic reaction of fly ash are accelerated, the strengths of fly ash concrete and mortar are enhanced noticeably, especially the early strength. With a mixture design of 200 kg/m3 OPC (Ordinary Portland Cement), 200 kg/m3 fly ash and 50 kg/m3 GH admixture, the strength of concrete at 1 d, 3 d and 28 d reaches 25 Mpa, 50 Mpa and 70 Mpa respectively.

  14. 流变学的水泥砂浆螺旋输送机理%RESEARCH ON SCREW CONVEYING MECHANISM FOR CEMENT MORTAR BASED ON RHEOLOGY

    Institute of Scientific and Technical Information of China (English)

    张永顺; 丁凡

    2001-01-01

    简要介绍了油田水泥砂浆衬里注水管道补口作业机器人的系统结构及工作原理,以水泥砂浆流变学为基础,建立了螺旋输送物理模型,对机器人螺旋送料作业装置的输送机理进行了研究,通过引入螺旋输送效率的概念,解决了水泥砂浆螺旋输送的定量计算问题,进而实现了机器人自主喷涂补口作业的水泥砂浆输送量的准确控制,保证了补口作业质量。实验证明理论分析的正确性,目前该机器人已交付大庆油田在工程中推广应用。%The systematical structure and operation principle of a welding seam anti-corrosion applicator in-pipe robot for water injection pi peline with cement mortar liner in oilfield is introduced briefly,the physical m odel of cement mortar by screw conveying is set up on the basis of its rheology ,then screw conveying mechanism of cement mortar when being conveyed by operatio n unite of the in-pipe robot is analyzed,by introducing the concept of screw co nveying efficiency,the quantitative calculation of cement mortar being conveyed by screw conveyor is solved,as a result,that makes the accurate quantitative co ntrol for cement mortar through screw conveying feasible when robot mending the welding seem by harmonious operation,the quality of the mending operation is gua ranteed,the experiments show the rightness of the theoretical analysis,this robo t has already been found its application in Daqing Oil Field.

  15. 酸雨侵蚀对水泥砂浆力学性能的影响%Effect of acid rain attack on mechanical properties of cement mortar

    Institute of Scientific and Technical Information of China (English)

    李军

    2015-01-01

    研究了不同水胶比、不同胶凝材料的水泥砂浆受酸雨侵蚀后的力学性能变化。结果表明:在酸雨侵蚀条件下,砂浆抗压强度和抗折强度呈现先快速增长,而后迅速降低的趋势,且水灰比越小,强度增长和下降速度越快;粉煤灰掺量越高,56 d以前强度增长越快,56 d以后强度下降速度越缓慢;28 d前掺矿粉砂浆在酸雨中的抗压强度增长幅度高于未掺加矿粉的基准砂浆,且矿渣掺量越高砂浆抗压强度越高,矿粉对砂浆抗折强度的作用相对较小。%The mechanical properties of cement material of various water cement ratio and cement mortar under acid rain stress were studied. The results show that the compressive strength and bending strength of mortar show a rapid increase under acid rain stress,and then decrease,the strength increases and the decrease rate is faster when the water cement ratio is small. The strength of cement with the increase of fly ash show a rapid growth before 56d and a slow down after 56 d.The compressive strength of mortar with mineral powder increased more than that of control sample under acid rain stress before 28 d,The strength of mortar would be increased with the propor-tions of slag increased ,and mineral powder has little effect on the flexural strength of mortar.

  16. Experimental study on the basic properties of cement admixture containing waste mortar powder%废砂浆粉作为水泥混合材的基本性能试验研究

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The article studies the basic properties of the waste mortar powder and the influence of it as a cement ad⁃mixture on the main properties of cement mortar, including grinding performance, water amount of normal consisten⁃cy, mobility and strength. Results show that waste mortar powder of fluidity of cement mortar is decreased and water amount of normal consistency is increased. And the fineness and content of waste mortar powder will affect the strength of cement mortar, bend-press ratio is increased, the material ductility is better.%研究了废砂浆粉基本性能及作为水泥混合材对水泥胶砂主要性能的影响,包括粉磨性能、标准稠度需水量、流动性和强度。结果表明,掺入废砂浆粉的混合水泥胶砂流动度有所下降,标准稠度需水量增加。而且废砂浆粉的细度和掺量都会影响强度,混合水泥折压比有所增长,材料延性较好。

  17. Influence of Fly Ash and Slag Powder on Autogenous Shrinkage of Cement Mortars%粉煤灰和矿粉对水泥胶砂自收缩的影响

    Institute of Scientific and Technical Information of China (English)

    肖佳; 陈雷; 邢昊

    2011-01-01

    试验研究了粉煤灰和矿粉对水泥胶砂自收缩的影响.结果表明:当胶砂比(质量比)为1∶0.5,水胶比(质量比)为0.3时,随水化龄期延长,水泥胶砂自收缩增大,早期自收缩发展急剧.粉煤灰降低了水泥胶砂的自收缩,随着粉煤灰掺量(质量分数)增大,水泥胶砂自收缩减小;掺10%和20%粉煤灰水泥胶砂的21d自收缩较纯水泥胶砂分别下降了21.1%和29.5%.水化早期(5d前),矿粉掺量(质量分数)在10%~20%时,随着矿粉掺量增大,水泥胶砂自收缩降低;掺10%和20%矿粉水泥胶砂的21 d自收缩较纯水泥胶砂分别增加了11.1%和6.6%.%The influence of fly ash and slag powder on the autogenous shrinkage of cement mortars was studied. The experiment test results indicate that the autogenous shrinkage of cement mortar made with 1:0. 5 binder to sand ratio(by mass) and 0. 3 water to binder ratio(by mass) increases with development of hydration. At early age, rate of autogenous shrinkage develops sharply. Addition of fly ash reduces the autogenous shrinkage of cement mortar, and the autogenous shrinkage of cement mortar decreases with increase of fly ash content(by mass). Compared to pure cement mortar, after hydrated for 21 d , the 10% and 20% of fly ash addition reduce autogenous shrinkage of cement mortar by 21. 1% and 29. 5% respectively. Originally within 5 d, the 10%- 20% (by mass) of slag powder addition decreases autogenous shrinkage of cement mortar. Compared to pure cement mortar, after hydrated for 21 d, the 10% and 20% of slag powder addition increase autogenous shrinkage of cement mortar by 11. 1% and 6. 6% respectively.

  18. Performance Characteristics of Waste Glass Powder Substituting Portland Cement in Mortar Mixtures

    OpenAIRE

    Kara, P; Csetényi, L; Borosnyói, A

    2014-01-01

    In several countries, waste glass causes environmental concerns as quantities stockpiled exceed recycling in the packaging stream. Being amorphous and having relatively high silicium and calcium contents, glass is pozzolanic or even cementitious, when finely ground. Reducing particle sizes typically to less than 100 µm may give control over the alkali-silica reaction in concrete, therefore making this material a possible substitute to Portland cement. Such use may moderate the problem of dump...

  19. 水泥砂浆孔结构分形特征的研究%Study of Pore Fractal Characteristic of Cement Mortar

    Institute of Scientific and Technical Information of China (English)

    金珊珊; 张金喜; 陈春珍; 陈炜林

    2011-01-01

    利用压汞仪测定了不同水灰比及龄期水泥砂浆的孔结构,通过基于热力学关系的分形模型计算得到了水泥砂浆的孔表面积分形维数,并探讨了孔表面积分形维数与微观孔隙率、孔表面积、平均孔径、中值孔径等其他孔结构参数及砂浆强度之间的关系.结果表明:基于热力学关系的分形模型能够很好地表征水泥砂浆孔隙的复杂程度;孔表面积分形维数与微观孔隙率的相关性较差,而与孔表面积、平均孔径、中值孔径以及强度之间有较好的相关关系;随着孔表面积分形维数的增大,平均孔径和中值孔径减小,孔表面积增加,水泥砂浆的抗折强度及抗压强度增加.基于热力学关系的分形模型计算得到的孔表面积分形维数可作为水泥砂浆孔结构特征的综合评价指标,并且分形维数与其宏观力学性能相关性良好.%Pore structure of cement mortar was tested by mercury intrusion porosimetry(MIP) with different water-cement ratio at different age.Fractal model based on thermodynamic method was used in calculation of pore surface fractal dimension of cement mortar.The relationships between pore surface fractal dimensions and porosity, pore surface area, average pore diameter, median pore diameter and strength of mortar were studied.The results indicate that pore surface fractal dimension which is calculated by fractal model based on thermodynamic method can represent the complexity of pore structure very well, and pore surface fractal dimension has poor correlation with porosity but good correlation with pore surface area,average pore diameter,median pore diameter and strength.As pore surface fractal dimension increases,average pore diameter and median pore diameter of cement mortar decrease,and pore surface area and strength of mortar increase.Thus, pore surface fractal dimension that is calculated by fractal model based on thermodynamic method can be assumed as integrative

  20. Study of Effect of Fly Ash on Fluidity and Strength of Cement Mortar%粉煤灰对水泥砂浆流动度和强度的影响研究

    Institute of Scientific and Technical Information of China (English)

    姚立阳; 姚丽红; 汪潇; 杨留栓

    2013-01-01

    Detailed study of fluidity and strength of cement mortar mixed with I Grade fly ash at different content showed that fly ash could improve the performance of cement mortar effectively. With water to binder ratios increasing, the fluidity of cement mortar with fly ash increased, higher fly ash content, the larger the fluidity. The early strength of cement mortar reduced slightly because fly ash admixed, but later strength increased, especially at 30%amount, 28d strength of cement mortar reached to peak.%通过对不同掺量时的Ⅰ级粉煤灰水泥砂浆的流动度和强度的研究,结果表明,粉煤灰的掺入可以有效改善水泥砂浆的性能。随水胶比增大,可使粉煤灰水泥砂浆的流动度得到提高,而且流动度随粉煤灰掺量的增加而增加;粉煤灰的掺入早期强度有所降低,但后期强度得到了提高,尤其是当粉煤灰掺量为30%时,28 d 龄期时强度达到最高。

  1. Modifications on Microporosity and Physical Properties of Cement Mortar Caused by Carbonation: Comparison of Experimental Methods

    Directory of Open Access Journals (Sweden)

    Son Tung Pham

    2013-01-01

    Full Text Available The influence of carbonation on the microstructure of normalised CEM II mortar was studied using nitrogen adsorption and porosity accessible to water. Samples were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity, and 20% CO2 concentration. Conflicts in results were observed because while the pore size distributions calculated by BJH method from nitrogen adsorption provided evolution of the micro- and mesopores during carbonation, the porosity accessible to water showed changes in all three porous domains: macro-, meso- and micropores. Furthermore, the porous domains explored by water and nitrogen molecules are not the same because of the difference in the molecular sizes. These two techniques are therefore different and help to complementarily evaluate the effects of carbonation. We also examined the evolution of macrophysical properties such as the solid phase volume using helium pycnometry, gas permeability, thermal conductivity, thermal diffusivity, and longitudinal and transverse ultrasonic velocities. This is a multiscale study where results on microstructural changes can help to explain the evolution of macro physical properties.

  2. STUDY ON PASTES AND MORTARS OF PORTLAND CEMENT WITH REPLACEMENT BY SANITARY WARE

    Directory of Open Access Journals (Sweden)

    Silvina Zito

    2016-06-01

    Full Text Available In this paper the Sanitary Faience, use as a replacement for portland cement is analyzed. Replacements used were 8, 24 and 40% by weight; the assays used contemplated the evolution of hydration from the first minutes (up to 48 hours by calorimetry, and from 2 days (to 28 days by the fixing of calcium hydroxide, water chemically combined, mechanical flexural and compression and porosity. The results showed that with increasing the percentage of replacement, at the earliest ages the effect of dilution overlaps and contrats with the physical stimulation; and at the 28 days all blends showed, as well as physical stimulation, chemistry stimulation, trough of pozzolanic reactivity.

  3. Dosification of a cement-talc-chamotte refractory mortar subjected to thermal shock

    OpenAIRE

    Kittl, P.; Díaz, G.; Alarcón, H.

    1992-01-01

    A cement-talc-chamotte refractory mixture was dosified by subjecting the same to thermal shock. To this end, specimens compacted to 350 Kg/cm2 through compression as well as specimens compacted manually were prepared. All the specimens were submitted to an initial working temperature of 1000ºC and then left to cool down to room temperature. The thermal shock was originated by heating the specimens in an oven till reaching a certain temperature T¡ ...

  4. Influence of the activators’ type and content on the properties of no cement mortars%激发剂种类及掺量对无水泥砂浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    张海龙; 裴长春

    2015-01-01

    为了优化工业垃圾粉煤灰、高炉矿渣及生石灰作为胶凝材料的无水泥砂浆配合比设计,提高无水泥砂浆的基础性能,试验通过改变碱性激发剂的种类及掺量,研究了无水泥砂浆的表观密度及力学性能,得出了一些有价值的结论。%In order to optimize the mix design of no cement mortars with fly ash, blast furnace slag and lime as cementitious materials and to im-prove the performance of no cement mortars, the test studied the apparent density and mechanical properties of no cement mortars by changing the type and dosage of alkaline activator, some valuable conclusions are obtained.

  5. Efeito do tempo de cura na rigidez de argamassas produzidas com cimento Portland Effect of the curing time on the stiffness of mortars produced with Portland cement

    Directory of Open Access Journals (Sweden)

    G. C. R. Garcia

    2011-03-01

    Full Text Available O concreto de cimento Portland é um dos materiais mais usados no mundo inteiro, entretanto, devido a sua estrutura ser muito complexa, torna-se imprescindível estudar suas propriedades com bastante profundidade. O concreto é produzido a partir de uma argamassa, de areia e cimento, com adição de agregados graúdos, sendo que suas propriedades estão basicamente suportadas nessa argamassa de constituição. O objetivo deste trabalho foi estudar a variação da rigidez de duas argamassas de composições com razão cimento:areia de 1:2 e 1:3 em função do tempo de cura, tendo como parâmetro a variação do módulo de Young. Os resultados mostraram que o módulo de Young cresce até atingir o valor máximo no oitavo dia, sendo que nos três primeiros dias esse crescimento é mais acentuado. A análise dos resultados indica que grande parte do processo de hidratação do cimento, com formação das ligações químicas responsáveis pela rigidez da argamassa, acontece nos primeiros dias de cura.Concrete produced with Portland cement is one of building materials most widely used worldwide. However, due to its highly complex structure, its properties require in-depth studies. Concrete is a mortar consisting of a mixture of cement, sand and coarse aggregates, and its properties are represented basically by the mortar base. The aim of this work was to study the change in stiffness of two mortar compositions cured at 25 ºC with a cement-to-sand ratio of 1:2 and 1:3, as a function of curing time using the variation of Young modulus as the measuring parameter. The results showed that Young modulus increases up to a maximum value on the 8th day, and that this increase is more pronounced during the first three days. An analysis of the results indicates that a large part of the cement hydration process, involving the formation of chemical bonds that are responsible for the mortar stiffness, takes place in the early days of curing.

  6. Dosification of a cement-talc-chamotte refractory mortar subjected to thermal shock

    Directory of Open Access Journals (Sweden)

    Kittl, P.

    1992-03-01

    Full Text Available A cement-talc-chamotte refractory mixture was dosified by subjecting the same to thermal shock. To this end, specimens compacted to 350 Kg/cm2 through compression as well as specimens compacted manually were prepared. All the specimens were submitted to an initial working temperature of 1000ºC and then left to cool down to room temperature. The thermal shock was originated by heating the specimens in an oven till reaching a certain temperature T¡ and then quenching the same through immersion in water at 20ºC; temperature T¡ was varied between 170ºC and 970ºC by means of 100ºC increments. The optimum dosification amounting to 90 % cement-talc and 10 % chamotte was obtained by studying mean stress at compression fracture of five cement-talc-chamote mixtures as a function of thermal shock. In addition, thermal fatigue exhibited by the optimum dosification was studied through the determination of mean loss in compressive strength, which amounted to 52% after 7 cycles with ΔT = 500ºC.

    Se dosificó una mezcla refractaria cemento-talco-chamota sometiéndola a un choque térmico. Con este objeto se fabricaron probetas compactadas a 350 kg/cm2 mediante compresión y probetas compactadas manualmente. Se aplicó a todas ellas una temperatura inicial de trabajo a 1.000 ºC, luego se las dejó enfriar hasta que alcanzaran la temperatura de sala del laboratorio. El choque térmico se originó calentando las probetas en un horno hasta una temperatura T¡ y luego se las enfrió súbitamente sumergiéndolas en agua a 20 ºC; la temperatura T¡ varió entre 170 ºC y 970 ºC con incrementos de 100 ºC. La dosificación óptima, 90% cemento-talco y 10% chamota, se obtuvo estudiando la tensión media de fractura a la compresión de cinco mezclas de cemento-talco-chamota en función del choque térmico. Se estudió además la fatiga térmica de la dosificación óptima determinando la

  7. Influence of chloride in mortar made of Portland cement types II, III, and V on the near-field microwave reflection properties

    Science.gov (United States)

    Hu, Cairong; Benally, Aaron D.; Case, Tobias; Zoughi, Reza; Kurtis, Kimberly

    2000-07-01

    Corrosion of steel rebar in reinforced concrete structures, can be induced by the presence of chloride in the structure. Corrosion of steel rebar is a problematic issue in the construction industry as it compromises the strength and integrity of the structure. Although techniques exist for chloride detection and its migration into a structure, they are destructive, time consuming and cannot be used for the interrogation of large surfaces. In this investigation three different portland cement types; namely, ASTM types II, III and V were used, and six cubic (8' X 8' X 8') mortar specimens were produced all with water-to-cement (w/c) ratio of 0.6 and sand-to-cement (s/c) ratio of 1.5. Tap water was used when producing three of these specimens (one of each cement type). For the other three specimens calcium chloride was added to the mixing tap water resulting in a salinity of 2.5%. These specimens were placed in a hydration room for one day and thereafter left it the room temperature with low humidity. The reflection properties of these specimens, using an open-ended rectangular waveguide probe, were monitored daily at 3 GHz (S-band) and 10 GHz (X-band). The results show the influence of cement type on the reflection coefficient as well as the influence of chloride on the curing process and setting time.

  8. Effect of cement sand ratio on industrial waste residue dry-mixed mortar properties%灰砂比对工业废渣干混砂浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘秀伟; 杨林; 秦贤顺

    2015-01-01

    研究了高掺量磷渣粉、粉煤灰干混砂浆的灰砂比对砂浆性能的影响及激发剂对砂浆的作用机理。结果表明,在砂浆稠度基本不变的前提下,随着灰砂比减小,砂浆和易性变差,凝结时间延长,抗压强度降低,拉伸黏结强度逐渐减小,28 d干缩逐渐增大,但在灰砂比为1:1~1:6的范围内其性能均能满足GB/T 25181—2010《预拌砂浆》中对应等级标准要求,调整灰砂比可以配制出M5.0~M30不同强度等级的普通干混砂浆。%Study on the mechanism of effect of high content of phosphorus slag powder,fly ash dry mixed mortar cement sand ratio on the properties of mortar and activator on the mortar. The results show that,on the premise of mortar consistency basically unchanged, with the cement sand ratio decreases,mortar workability variation,extended the setting time,compressive strength decreases,the tensile bond strength decreases,28 d shrinking gradually increased,but in the cement sand ratio is in the range of 1:1~1:6 and its performance can meet the GB/T 25181—2010 ready mixed mortar in the corresponding grade standards,adjust the cement sand ratio can be prepared M5.0~M30 of different strength grade of ordinary dry mixed mortar.

  9. Experiment and Study for Corrosion of Fly Ash Cement Mortar by Sulfuric Acid%掺粉煤灰水泥砂浆抗稀硫酸侵蚀的试验研究

    Institute of Scientific and Technical Information of China (English)

    李燕涛; 宋志刚; 闵红光

    2012-01-01

    为研究稀硫酸侵蚀掺粉煤灰水泥砂浆的规律,对砂浆试块进行长期浸泡试验,用滴酸法间接测得腐蚀速率并结合偏相关理论分析了影响砂浆试块腐蚀速率各个因素.分析表明:pH值相同时,粉煤灰掺量0%~3 0%的砂浆试块的腐蚀过程符合浓度边界层溶解反应模型;试块的流动度与抗腐蚀能力呈负相关;掺粉煤灰并不能明显改善水泥砂浆的抗稀硫酸侵蚀的性能.%A long time immersion test of fly ash cement mortar in dilute sulfuric acid was carried out to study the mechanisms of corrosion-resistant. The rate of mortar corrosion was indirectly recorded and combining with the theory of partial correlation, the parameters that can affect the rate were obtained. It was showed that in soak solution with the same pH value, corrosion process of cement mortar with 0%~30% fly ash can reflect the dissolving reaction model of consistency boundary, with the fluidity of cement mortar inversely related to corrosion -resistant capability of cement mortar. The corrosion-resistant capability of cement mortar can not be improved remarkably by fly ash.

  10. 改性稻壳水泥砂浆的性能研究%Study on properties of modified rice husk cement mortar

    Institute of Scientific and Technical Information of China (English)

    左洁; 董莪; 刘杰胜

    2016-01-01

    The potential value of rice husk will have important social significance as a green resource. This paper mainly studies the macroscopic physical properties of modified rice husk cement mortar. The results show that dif⁃ferent incorporation amount of modified rice husk has different degrees of impact on the porosity, water absorption, consistency and water retention of the cement mortar.%稻壳作为大宗废料处理是一种浪费,研究稻壳的潜在价值将其作为一种绿色资源具有重要的社会意义。主要研究改性稻壳水泥砂浆的宏观物理性能。通过试验得出,掺入不同量的改性稻壳对水泥砂浆的孔隙率、吸水率、稠度、保水率有不同程度的影响。

  11. 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.

  12. Use of copper slag in cement mortar Uso de escória de cobre na fabricação de argamassas de cimento

    Directory of Open Access Journals (Sweden)

    Amin Salvador Nazer

    2012-03-01

    Full Text Available The use of a Chilean copper smelter slag in the manufacture of cement mortars was studied. Copper slag was characterized from the chemical, mineralogical and size distribution point of view. In addition, different Chilean standards were used to determine some important parameters of the waste and to perform compression and flexural assays of the cement mortars. The results obtained showed that the mortars manufactured with copper slag present a higher resistance to compression and flexural than those manufactured with river sand. It is concluded that this metallurgical residue can be used in civil construction.Estudou-se a utilização da escória de cobre de uma fundição do Chile na fabricação de argamassas de cimento. A escória foi caracterizada através de análise química, mineralógica e granulométrica. Também foram usados diferentes padrões para se conhecerem alguns parâmetros importantes da escória e se fazerem os ensaios de compressão e de flexão das argamassas. Os resultados mostraram que as argamassas feitas com escória de cobre apresentaram maior resistência à compressão e à flexão que as preparadas com areia. O estudo conclui que esse resíduo metalúrgico poderia ser utilizado na construção civil.

  13. Pengaruh Perendaman Air Laut Terhadap Kualitas Mortar Semen

    OpenAIRE

    Damayanti, Mentari C.; Rauf, Nurlaela; Juarlin, Eko

    2015-01-01

    This research of fabrication cement with adding sugarcane bagasse ash (SBA) as pozzolan. Then chemical composition of cement sample is measured by XRF, setting time of cement and mortar compressive strength is examined with and without immersion. The result showed sea water gives influence for mortar compressive strength. Mortar compressive strength without immersion increases with 6% persentage composition of SBA. While mortar compressive strength with immersion of sea water decreases along ...

  14. Behaviour of corroded steel in a Ca(OH2-saturated solution and in cement mortar. Possibility of rehabilitation

    Directory of Open Access Journals (Sweden)

    Hernández, L. S.

    2007-03-01

    Full Text Available The present study compared the response of rust-free and corroded steel electrodes in Ca(OH2-saturated solutions and in cement mortar, essentially defined in terms of polarization resistance as measured with gravimetric, metallographic and electrochemical methods. Answers were sought for the following questions, which persist despite the use of reinforced concrete (RC in building for over a century: At what corrosion rate is RC durability seriously compromised? Does restoration of the initial conditions in properly manufactured concrete guarantee repassivation of corroded steel? Does the use of inhibitors enhance repassivation? Does the nature of the corrosion products have any significant effect on the response of corroded steel reinforcement? The results obtained in indicated that the effectiveness of preventive methods is much more closely related to the degree of existing corrosion than to the nature of the corrosion products.En el presente trabajo se analizan las respuestas de electrodos de acero, limpios y precorroídos, en soluciones saturadas de Ca(OH2 y en mortero de cemento, recurriendo para ello a técnicas gravimétricas, metalográficas y electroquímicas, esencialmente a medidas de resistencia de polarización. Se intenta encontrar respuesta a las siguientes dudas persistentes después de más de un siglo de utilización de las estructuras de hormigón armado (EHA: ¿qué velocidades de corrosión comprometen seriamente la durabilidad de las EHA? ¿La restauración de las condiciones iniciales de un hormigón correctamente fabricado garantiza la recuperación del estado pasivo en los refuerzos ya corroídos? ¿La utilización de inhibidores facilita la repasivación de los refuerzos? ¿Cambia la naturaleza de los productos de corrosión sustancialmente la respuesta de las armaduras ya corroídas? Los resultados obtenidos indican que la eficacia de las medidas preventivas resulta mucho más condicionada por el grado de

  15. 含砂量对水泥砂浆强度与孔结构的影响%Effect of Sand Content on Strength and Pore Structure of Cement Mortar

    Institute of Scientific and Technical Information of China (English)

    周继凯; 金龙; 丁宁

    2013-01-01

    Results of a study conducted to evaluate the effect of four sand content on the compressive,flexural and splitting-tensile strength of cement mortar are report.An experimental investigation in the pore structure of cement mortar brought about by changing the sand content and water/cement ratio is also reportsed.The changes in the pore structure were quantified by measuring the porosity,and pore size distribution obtained using mercury intrusion porosimetry technique.Test results show that the strengths of cement mortar increase with increasing sand content.Sand content is an important parameter influencing the pore structure of cement mortar.Moreover,there is a good relationship between pore structure and strength of cement mortar.A quantative expression is given between strength and pore parameters.%探讨四种不同含砂量对水泥砂浆抗压、弯拉和劈拉强度的影响.通过试验研究了随着含砂量和水灰比的变化水泥砂浆孔结构的不同.通过测量孔隙率及压汞法测量孔径分布来描述水泥砂浆的孔结构.试验结果表明水泥砂浆的强度(弯拉,劈拉和抗压)随含砂量的增加而提高.含砂量对水泥砂浆的孔结构也有十分重要的影响,水泥砂浆强度与其孔结构间有一定的相关性,给出相对应孔结构参数(孔径分布与孔隙率)与强度的定量关系表达式.

  16. Biofouling e biodeterioração química de argamassa de cimento portland em reservatório de usina hidroelétrica Biofouling and chemical biodeterioration in hydroeletric power plant portland cement mortar

    Directory of Open Access Journals (Sweden)

    Kleber Franke Portella

    2009-01-01

    Full Text Available Last decade Brazilian rivers experimented progressive biofouling of Limnoperna fortunei communities and Cordylophora caspia hydroids. The microhabitat is so favorable that in around 1.5 years L. fortunei increased from 0.39 to nearby 149,000 units/m². Ten Portland cement mortar samples were produced with 1: 3.5: 0.4 dosages and installed for 1 year at Salto Caxias Brazilian Power Plant reservoir in 0.5 m and 1.0 m deep to investigate the biofouling influence on hydraulic civil structures. SEM, EDS, visual investigation and XRF results indicate none direct chemical interrelationships between L. fortunei and the mortar samples. However C. caspia diminished the mortar surface resistance and caused cement paste leaching.

  17. Influence of Rubber Aggregate on Pore Structure of Cement Mortar%橡胶集料对水泥砂浆孔结构的影响

    Institute of Scientific and Technical Information of China (English)

    张海波; 管学茂; 勾密峰; 刘小星

    2013-01-01

    孔结构是影响砂浆或混凝土性能的重要参数.通过压汞法研究了橡胶颗粒对砂浆孔隙率及孔径分布的影响规律,分析了橡胶颗粒对砂浆孔结构的影响机理.结果表明,随橡胶颗粒含量增加,橡胶砂浆最可几孔径增加,总孔隙率增加,其中大孔(D>1000 nm)含量增加最为明显,而凝胶孔(D<10 nm)含量变化不大.橡胶表面与水的接触角为99.5.,说明其具有憎水性,同时由于橡胶颗粒表面存在着大量凹坑,水在毛细管作用下无法充满橡胶颗粒表面凹坑,导致橡胶颗粒与水泥基体界面处存在大量孔径较大的孔隙.%Pore structure is an important factor for performance of rubber cement mortar and concrete.The pore structure and pore size distributions of rubber mortars with different amount of rubber granules addition was examined using mercury porosimetry,and the influence mechanism of rubber granules on pore structure of mortar was analyzed.The increasement of rubber granules addition results in the increasement of mode pore diameter and the total porosity,particularly for the amount of macropore(D〉1000 nm).Nevertheless,the amount of gel pore(D<10 nm)is proximally the same as that of specimen with no rubber addition.The examined contact angle of water against rubber is 99.5°,which suggests the hydrophobic nature of rubber surface.Due to rubber granules' hydrophobic surface and rough surface morphology,the water in mortar can not fill the dent in rubber surface,which illustrates the formation of the pore structure of transition zone between rubber and cement matrix.

  18. Sulfate Attack of Cement-Based Material with Limestone Filler Exposed to Different Environments

    Science.gov (United States)

    Gao, Xiaojian; Ma, Baoguo; Yang, Yingzi; Su, Anshuang

    2008-08-01

    Mortar prisms made with OPC cement plus 30% mass of limestone filler were stored in various sulfate solutions at different temperatures for periods of up to 1 year, the visual appearance was inspected at intervals, and the flexural and compressive strength development with immersion time was measured according to the Chinese standard GB/T17671-1999. Samples were selected from the surface of prisms after 1 year immersion and examined by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), laser-raman spectroscopy and scanning electron microscopy (SEM). The results show that MgSO4 solution is more aggressive than Na2SO4 solution, and Mg2+ ions reinforce the thaumasite sulfate attack on the limestone filler cement mortars. The increase of solution temperature accelerates both magnesium attack and sulfate attack on the limestone filler cement mortar, and leads to more deleterious products including gypsum, ettringite and brucite formed on the surface of mortars after 1 year storage in sulfate solutions. Thaumasite forms in the mortars containing limestone filler after exposure to sulfate solutions at both 5 °C and 20 °C. It reveals that the thaumasite form of sulfate attack is not limited to low-temperature conditions.

  19. 水泥砂孔隙特征对抗冻性影响的研究%Research of cement mortar air content on the effects of pore characterstics and frost resistance

    Institute of Scientific and Technical Information of China (English)

    陈松; 李建新; 王起才; 李伟龙

    2015-01-01

    Through the frost resistance test,mercury intrusion test,hole spacing coefficient test to determine the cement mortar pore structure characteristics and the frost resistance under different air content,study the relationship between frost resistance and cement mortar pore structure characteristics,in addition,also analyzed the compressive strength of cement mortar under different air content. Ex-perimental results show that the as increase of air content the pore porosity of cement mortar,total pore volume,total hole area,average pore diameter are all increased,hole spacing coefficient decreases,and improved pore structure internal of cement mortar ,and pore size distribution more uniform and reasonable,although the strength decreases a bit,but the frost resistance was improved greatly.%通过抗冻性试验、压汞试验、孔间距系数试验测定了不同含气量下水泥砂的浆孔结构特征及其抗冻性,研究了抗冻性与孔结构之间的关系,此外,还分析了不同含气量水泥砂浆的抗压强度。试验结果表明:含气量的增加使水泥砂浆孔隙率、总孔体积、总孔面积、平均孔径均增加,孔间距系数减小,改善了其内部孔结构,孔径分布也比较均匀合理,虽然其强度有所降低,但大大提高了抗冻性。

  20. Microstructure and Composition of Hydration Products of Ordinary Portland Cement with Ground Steel-making Slag

    Institute of Scientific and Technical Information of China (English)

    LI Yong-xin; CHEN Yi-min; ZHANG Hong-tao; HE Xing-yang; WEI Jiang-xiong; ZHANG Wen-sheng

    2003-01-01

    The effect of ground steel-making slag on microstructure and composition of hydration products of ordinary Portland cement (OPC) was investigated by mercury intrusion porosimetry ( MIP ), X- ray diffraction (XRD) and differential thermal analysis (DTA). Results show that ground steel-making slag is a kind of high activity mineral additives and it can raise the longer-age strength of OPC mortar. The total porosity and average pore diameter of OPC paste with groand steel-making slag increase with the increase of the amount of ground steelmaking slag replacing OPC at various ages, while after 28 days most pores in OPC paste with ground steel-making slag do not influeace the strength because the diameter of those pores is in the rang of 20 to 50nm. The hydration mechanism of ground steel-making slag is similar to that of OPC but different from that of fly ash and blast furnace slag. The hydration products of ground steel-making slag contain quite a lot of Ca( OH)2 in long age.

  1. Low Carbon Footprint Mortar from Pozzolanic Waste Material

    OpenAIRE

    Taha Mehmannavaz; Salihuddin Radin Sumadi; Muhammad Aamer Rafique Bhutta; Mostafa Samadi; Seyed Mahdi Sajjadi

    2014-01-01

    Nowadays, Portland cement clinker leads to emission of CO2 into the atmosphere and therefore causes greenhouse effect. Incorporating of Palm Oil Fuel Ash (POFA) and Pulverized Fuel Ash (PFA) as partial cement replacement materials into mix of low carbon mortar decreases the amount of cement use and reduces high dependence on cements compared to ordinary mortar. The result of this research supported use of the new concept in preparing low carbon mortar for industrial constructions. Strength of...

  2. 水泥乳化沥青砂浆孔体积的分形特征%Fractal Characteristic of Pore Volume of Cement and Asphalt Mortar

    Institute of Scientific and Technical Information of China (English)

    傅强; 郑克仁; 谢友均; 周锡玲; 蔡锋良

    2013-01-01

    The volume fractal characteristic of pores with the size of >1000nm in cement and asphalt mortar (CA mortar) was deter-mined by mercury intrusion porosimetry. The effect of internal physical and chemical properties of CA mortar on the fractal charac-teristic of pore volume was analyzed. The results show that the most probable pore diameter and the volume of pores with the size of >5000nm decrease,while the big capillary pores in the size range from 1000nm to 5000nm increase with the increase of age. The formation and filling effect of the hydration products of cement are the main influence factors that cause this phenomenon. The fractal dimension increases with the increase of age, but the increased rate reduces due to the influence of asphalt membrane on cement hy-dration. The porosity and the average of pore diameter decrease with the increase of fractal dimension, further indicating that the in-crease of fractal dimension is a continuous optimization of pore structure inside of CA mortar. The compressive strength and elastic modulus increase, the increased rate decreases when the fractal dimension increases. The fractal dimension is the indirect characteri-zation parameter of macro-mechanical property of CA mortar.%采用压汞测孔试验研究了水泥乳化沥青砂浆(CA砂浆)1000 nm以上孔径孔隙的体积分形特征,并进一步分析了CA砂浆内部微细观物理化学性能对其孔体积分形特征的影响机理。结果表明:随着龄期的增加,最可几孔径逐渐减小,CA砂浆内部孔径在5000 nm以上的孔隙体积逐渐减少,孔径为1000~5000 nm的大毛细孔体积逐渐增加,水泥水化产物的形成及其填充作用是主要影响因素;分形维数随龄期增加而逐渐增大,沥青膜对水泥水化的影响是分形维数增加速率逐渐减慢的主要原因;孔隙率和平均孔径随分形维数的增加而逐渐减小,进一步证明了分形维数的增大象征着CA砂浆内部孔结构的优化。

  3. Laboratory investigation of the influence of two types of modified hydrotalcites on chloride ingress into cement mortar

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.; Polder, R.

    2015-01-01

    Owing to the unique molecular structure and high ion exchange capacity, hydrotalcites are believed to have a potential to be modified and tailor-made as an active component of mortar and/or concrete. In this paper, two types of modified hydrotalcites (MHT-pAB and MHT-NO2) were incorporated into ceme

  4. Fly and bottom ashes from biomass combustion as cement replacing components in mortars production: rheological behaviour of the pastes and materials compression strength.

    Science.gov (United States)

    Maschio, Stefano; Tonello, Gabriele; Piani, Luciano; Furlani, Erika

    2011-10-01

    In the present research mortar pastes obtained by replacing a commercial cement with the equivalent mass of 5, 10, 20 and 30 wt.% of fly ash or bottom ash from fir chips combustion, were prepared and rheologically characterized. It was observed that the presence of ash modifies their rheological behaviour with respect to the reference blend due to the presence, in the ashes, of KCl and K2SO4 which cause precipitation of gypsum and portlandite during the first hydration stages of the pastes. Hydrated materials containing 5 wt.% of ash display compression strength and absorption at 28 d of same magnitude as the reference composition; conversely, progressive increase of ash cause a continuous decline of materials performances. Conversely, samples tested after 180 d display a marked decline of compression strength, as a consequence of potassium elution and consequent alkali-silica reaction against materials under curing.

  5. Study on the property of cement mortar with scrap rubber powder%橡胶粉水泥砂浆的性能研究

    Institute of Scientific and Technical Information of China (English)

    杨文华; 吴法宝

    2011-01-01

    本文以不同掺量废轮胎橡胶粉取代部分细集料的方法,研究橡胶粉的掺量对橡胶水泥砂浆流动度和和物理力学性能的影响。实验结果表明流动度随着胶粉掺量的增大而增大,强度随着胶粉掺量增加而降低。%The effect on mobility and mechanical property of cement mortar were investigated respectively when additive composition of scrap tire powder replaces part of sand.The result showed mobility was up, but strength was down with increasing scrap tire powder.

  6. Inorganic contaminants attenuation in acid mine drainage by fly ash and fly ash-ordinary Portland cement (OPC) blends : column experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gitari, W.M. [Venda Univ., Thohoyandou (South Africa). Dept. of Ecology and Resources Management, School of Environmental Studies; Petrik, L.F.; Etchebers, O. [Western Cape Univ., Bellville (South Africa). Environmental and Nanosciences Group, Dept. of Chemistry; Key, D.L. [Western Cape Univ., Bellville (South Africa). Dept. of Chemistry; Okujeni, C. [Western Cape Univ., Bellville (South Africa). Dept. of Earth Sciences

    2010-07-01

    The infiltration of acid mine drainage (AMD) material into mine voids is one of the environmental impacts of underground coal mining. In this study, the mitigation of AMD in a mine void was simulated in laboratory conditions. Various mixtures of fly ash, solid residues, and Portland cement were added to packed columns over a 6-month period. The fly ash additions generated near-neutral to alkaline pH levels, which in turn induced precipitation, co-precipitation, and adsorption contaminant attenuation mechanisms. A modelling study demonstrated that the precipitation of ferrihydrite, Al-hydroxides, Al-oxyhydroxysulphates, gypsum, ettringite, manganite, and rhodochrosite lowered contaminant levels. Results of the study indicated that the pH regime and acidity level of the AMD strongly influenced both the leaching of the toxic trace elements as well as the attenuation of the AMD. 3 refs., 2 figs.

  7. The effects of BaSO4 loading on OPC cementing system for encapsulation of BaSO4 scale from oil and gas industry

    International Nuclear Information System (INIS)

    Highlights: • Fine BaSO4 powder can promote the formation of CaCO3 in the wasteform. • w/c = 0.53 is better than w/s = 0.53 to maintain the low porosity and low carbonation. • Water has little impact on the formation of CaCO3 when coarse BaSO4 was introduced. • It is possible to load 60 wt% of BaSO4 with a sufficient integrity of wasteform. -- Abstract: The BaSO4 scales obtained from piping decontamination from oil and gas industries are most often classified as low level radioactive waste. These wastes could be immobilised by stable cement matrix to provide higher safety of handling, transportation, storage and disposal. However, the information available for the effects of the basic formulation such as waste loading on the fundamental properties is still limited. The present study investigated the effect of BaSO4 loading and water content on the properties of OPC–BaSO4 systems containing fine BaSO4 powder and coarse granules. The BaSO4 with different particle size had a marked effect on the compressive strength due to their different effects on hydration products formed. Introduction of fine BaSO4 powder resulted in an increased formation of CaCO3 in the system, which significantly contributed to the compressive strength of the products. Amount of water was important to control the CaCO3 formation, and water to cement ratio of 0.53 was found to be a good level to maintain a low porosity of the products both for fine BaSO4 powder and coarse BaSO4 granule. BaSO4 loading of up to 60 wt% has been achieved satisfying the minimum compressive strength of 5 MPa required for the radioactive wasteforms

  8. Farklı Puzolanik Katkıların Çimento Harçlarının Mekanik Özelikleri Üzerine Etkisi = The Effect of Different Puzzolanic Additives on Mechanical Properties of Cement Mortars

    Directory of Open Access Journals (Sweden)

    H. Aygül YEPREM

    2004-06-01

    Full Text Available In this study, cement mortar samples containing fly ash obtained from Soma Power Plant, two different types of natural pozzolan supplied from Yenişehir and Bilecik and silica fume from Antalya Ferrocrom Industry partial replacement of cement clinker. The strength of the mortars prepared by these mixtures were investigated. The mixtures were prepared by using 10% fly ash and 5% silica fume and the trass contents varied as 30%, 35%, and 40%. Chemical analyses of these mixtures were carried out and Blaine specific surface area values were measured. In performed tests, the highest strength values were noticed in mortars containing natural puzzolan from Bilecik which has high fineness.

  9. 胶凝材料性质对干混砂浆抗压强度的影响研究%Influence of the properties of cementing materials on the unconfined compressive strengths of dry-mixed mortar

    Institute of Scientific and Technical Information of China (English)

    郑娟荣; 赵雪飞

    2014-01-01

    为了研究胶凝材料性质对干混砂浆抗压强度的影响规律,共制备了24组样品,其中3组样品的微观形貌和孔结构采用扫描电子显微镜和压汞测孔仪(Autopore IV 9500)等测试手段进行了分析。试验结果表明:无论胶凝材料是100%水泥、50%水泥+50%矿渣粉和50%水泥+50%粉煤灰,7 d和28 d砂浆抗压强度均随胶凝材料总量增加而明显提高,增加水泥掺量对砂浆早期强度有利;与以100%水泥为胶凝材料制备的砂浆相比,当每吨干混砂浆中胶凝材料总量分别为100、150、200、250 kg时,以50%水泥+50%矿渣粉为胶凝材料制备的砂浆的抗压强度分别提高47%、55%、10%和0,而以50%水泥+50%粉煤灰为胶凝材料制备的砂浆的抗压强度分别降低77%、66%、56%和44%。与15%水泥制备的砂浆28 d硬化体相比,7.5%水泥+7.5%矿渣制备的砂浆28 d硬化体中水化产物更多或更分散、基体与骨料结合更密实、总孔隙更低及孔径更细;7.5%水泥+7.5%粉煤灰制备的砂浆28 d硬化体中水化产物更少、基体更松散、总孔隙更高及孔径更大。%24 groups of samples were made so as to investigating the influence of the properties of cementing materials on the uncon-fined compressive strengths (UCS) of dry-mixed mortar.The morphology and pore structure of 3 groups of 24 samples were investigated by scanning electron microscope(SEM) and mercury intrusion porosimeter(Autopore IV 9500)(MIP).The results showed that the 7 d and 28 d UCS of hardened mortars increased with the increase of the total content of cementing materials no matter what cementing materials were 100%cement and 50%cement+50%slag powder and 50%cement+50%fly-ash ,and the increase of cement content was in favour of early strength of hardened mortar.Comparing with the hardened mortar of 100%cement as cementing material ,the 28 d UCS of the hard-ened mortar of 50%cement+50%slag powder as cementing material respectively

  10. 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.

  11. Evaluation of red mud as pozzolanic material in replacement of cement for production of mortars; Avaliacao da lama vermelha como material pozolanico em substituicao ao cimento para producao de argamassas

    Energy Technology Data Exchange (ETDEWEB)

    Manfroi, E.P.; Cheriaf, M.; Rocha, J.C., E-mail: elizmanfroi@yahoo.com.b, E-mail: malik@valores.ufsc.b [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Civil

    2010-07-01

    Red mud is a by-product of the alkaline extraction of aluminum from the bauxite and represents a renewed environmental problem due the significant annual throughput by the plants. In the present work, the pozzolanic properties of Brazilian red mud fired at 600, 700, 800 and 900 deg C were investigated by monitoring lime consumption using DTA analysis and Brazilian standard methodology NBR 5772 (1992). Products and kinetics of hydration were determined in cement pastes produced with 5 and 15% red mud using x-ray diffraction and DTA analysis. Compressive strength and capillary absorption tests were realized on mortars constituted by 5, 10 and 15% red mud in replacement of cement. When calcined at 600 deg C, the red mud develops good pozzolanic properties, and the compressive strength of mortars produced with this waste meet values in accordance with regulatory standard. These results shown than red mud can be used, in partial replacement of cement, as new construction material to produce sustainable mortars with low environmental impact. (author)

  12. Characteristics of Wood ASH/OPC Concrete

    OpenAIRE

    Abdullahi, M

    2006-01-01

    The study presents the behaviour of wood ash / OPC concrete. Chemical analysis of wood ash, bulk density, sieve analysis and specific gravity of wood ash and aggregates, consistency, setting time and slump test of the fresh paste were conducted to determine the suitability of the materials for concrete making. Mix ratio of 1:2:4 and percentage replacement level of 0, 10, 20, 30 and 40 percents of cement by wood ash were used. 150mm´150mm cubes were cast, cured and crushed at 28 and 60 days to...

  13. Crack-closing of cement mortar beams using NiTi cold-drawn SMA short fibers

    Science.gov (United States)

    Choi, Eunsoo; Kim, Dong Joo; Chung, Young-Soo; Kim, Hee Sun; Jung, Chungsung

    2015-01-01

    In this study, crack-closing tests of mortar beams reinforced by shape memory alloy (SMA) short fibers were performed. For this purpose, NiTi SMA fibers with a diameter of 0.965 mm and a length of 30 mm were made from SMA wires of 1.0 mm diameter by cold drawing. Four types of SMA fibers were prepared, namely, straight and dog-bone-shaped fiber and the two types of fibers with paper wrapping in the middle of the fibers. The paper provides an unbonded length of 15 mm. For bending tests, six types of mortar beams with the dimensions of 40 mm × 40 mm × 160 mm (B×H×L) were prepared. The SMA fibers were placed at the bottom center of the beams along with an artificial crack of 10 mm depth and 1 mm thickness. This study investigated the influence of SMA fibers on the flexural strength of the beams from the measured force- deflection curves. After cracking, the beams were heated at the bottom by fire to activate the SMA fibers. Then, the beams recovered the deflection, and the cracks were closed. This study evaluated crack-closing capacity using the degree of crack recovery and deflection-recovery factor. The first factor is estimated from the crack-width before and after crack-closing, and the second one is obtained from the downward deflection due to loading and the upward deflection due to the closing force of the SMA fibers.

  14. AUTOMATED TESTING OF OPC SERVERS

    CERN Document Server

    Farnham, B

    2011-01-01

    CERN relies on OPC Server implementations from 3rd party device vendors to provide a software interface to their respective hardware. Each time a vendor releases a new OPC Server version it is regression tested internally to verify that existing functionality has not been inadvertently broken during the process of adding new features. In addition bugs and problems must be communicated to the vendors in a reliable and portable way. This presentation covers the automated test approach used at CERN to cover both cases: Scripts are written in a domain specific language specifically created for describing OPC tests and executed by a custom software engine driving the OPC Server implementation.

  15. CRTSⅡ型水泥乳化沥青砂浆施工质量控制%Impacts Analysis of Gap and Construction Quality Control on CRTSⅡ Type Cement Asphalt Mortar

    Institute of Scientific and Technical Information of China (English)

    钟杰

    2014-01-01

    Based on the practical experience from the construction of Beijing-shanghai high-speed railway and beijing-tianjin intercity passenger dedicated line , the control points of construction quality of cement asphalt mortar are expounded. The common diseases in the construction are described and the causes of diseases are analyzed. Effects of gap between slab and cement asphalt mortar layer on the deformation and stress of track structure are studied on the base of elastic foundation beam theory and finite element method. The results show that the gap between slab and cement asphalt mortar layer has significance effect on the deformation of track structure. In order to guarantee the train running quality and durability of track, the construction quality of cement asphalt mortar must be control strictly, the gap between slab and cement asphalt mortar layer must be prevented and adjusting the construction technology and maintenance timely.%本文以京沪高速铁路和京津城际客运专线工程施工实践为基础,阐述了水泥乳化沥青砂浆层施工质量控制要点,对施工中常见病害进行了描述与原因分析,最后基于弹性地基梁理论与有限元方法,研究了砂浆层离缝对轨道结构受力和变形的影响。结果表明轨道板与水泥乳化沥青砂浆层之间的离缝将加剧轨道结构的变形,为了保证高速列车行车品质与轨道结构的耐久性,必须严格控制水泥乳化沥青砂浆的施工质量,防止灌浆时砂浆离缝的出现,并及时进行施工工艺调整与养护维修。

  16. A new surface-modified technology of cement mortar using calcium carbonate biodeposition%一种基于微生物沉积的水泥砂浆表面改性技术

    Institute of Scientific and Technical Information of China (English)

    朱飞龙; 李庚英; 杜虹; 崔鹏飞; 吴亚庆; 刘海峰

    2013-01-01

    The paper presents a new surface modification of cement mortar using biodeposition involving a method employing sporosarcina pasteurii (bacillus pasteurii) bacteria and using cement mortar power as covering layer. It was possible to obtain reduction in water absorption of cement mortars. The effect was more visible in case of using nutrient medium containing urea, and the coefficient of capillary suction of the treated cement mortar was reduced by 58%. Presence of spherical and columnar vaterite and calcite calcium carbonate crystals filling-voids in cement mortar was confirmed by observations under SEM and XRD. The total porosity reduced by 40% was demonstrated by using mercury intrusion porosimetry (MIP).%某些微生物能诱导沉积出具有胶凝和矿化作用的碳酸钙,可以用来修复和密实水泥基材料.但是目前微生物沉积技术工艺复杂,成本高,不利于推广和工程应用.尝试采用水泥砂浆粉作为覆膜载体,利用巴斯德芽孢杆菌对水泥砂浆进行表面处理.研究结果表明,采用该方法能使巴斯德芽孢杆菌在水泥试块表面诱导沉积出碳酸钙,有效减少水泥砂浆的吸水性能.当微生物采用含有尿素的培养基培养时,表面改性后的水泥砂浆吸水系数降低了58%.采用压汞测试仪(MIP)分析了处理前后水泥试块表层的孔隙率以及孔结构特征.发现采用巴斯德芽孢杆菌处理后,样品孔隙率显著降低,大孔的含量显著减少,当微生物采用含有尿素的培养基培养时,总孔隙率降低了40%.X射线衍射仪(XRD)和场发射扫描电镜(SEM)分析表明,经微生物技术处理后水泥试块内部的孔洞和裂缝被球霰石和方解石填充.

  17. Crack-closing of cement mortar beams using NiTi cold-drawn SMA short fibers

    International Nuclear Information System (INIS)

    In this study, crack-closing tests of mortar beams reinforced by shape memory alloy (SMA) short fibers were performed. For this purpose, NiTi SMA fibers with a diameter of 0.965 mm and a length of 30 mm were made from SMA wires of 1.0 mm diameter by cold drawing. Four types of SMA fibers were prepared, namely, straight and dog-bone-shaped fiber and the two types of fibers with paper wrapping in the middle of the fibers. The paper provides an unbonded length of 15 mm. For bending tests, six types of mortar beams with the dimensions of 40 mm × 40 mm × 160 mm (B×H×L) were prepared. The SMA fibers were placed at the bottom center of the beams along with an artificial crack of 10 mm depth and 1 mm thickness. This study investigated the influence of SMA fibers on the flexural strength of the beams from the measured force- deflection curves. After cracking, the beams were heated at the bottom by fire to activate the SMA fibers. Then, the beams recovered the deflection, and the cracks were closed. This study evaluated crack-closing capacity using the degree of crack recovery and deflection-recovery factor. The first factor is estimated from the crack-width before and after crack-closing, and the second one is obtained from the downward deflection due to loading and the upward deflection due to the closing force of the SMA fibers. (paper)

  18. Microstructure Formation in Cement Mortars Modified With Water-Soluble Polymers (Microstructuuropbouw bij cementmortels gemodificeerd met wateroplosbare polymeren)

    OpenAIRE

    KNAPEN, Elke

    2007-01-01

    Tijdens de uitharding van cementmortels gemodificeerd met wateroplosbare polymeren vinden er twee processen plaats: cementhydratatie en polymeerfilmvorming. Het hoofddoel van dit doctoraatswerk is het bestuderen van het effect van polymeeroplossingen op de cementhydratatiereacties, van de polymeer-cement interacties in een vroeg stadium en van de polymeerfilmvorming bij zeer lage polymeerconcentraties (1% van het cementgewicht). In de praktijk werd polymeerfilmvorming bij deze kleine poly...

  19. PVA 改性碳黑-水泥砂浆力学性能及微观结构%Mechanical properties and microstructure of carbon black modified cement mortar incorporating PVA

    Institute of Scientific and Technical Information of China (English)

    范杰; 李庚英; 熊光晶

    2016-01-01

    试验探讨了聚乙烯醇(PVA)及其掺量对纳米碳黑‐水泥砂浆力学性能的影响,结果表明:当PVA掺量为0.2%时,改性水泥砂浆的抗压、抗折强度和黏结弯曲强度分别提高了32.1%,12.2%和18.6%.采用扫描电镜、傅里叶红外光谱、X射线衍射光谱和差示扫描热分析仪观察了 PV A改性纳米碳黑‐水泥砂浆的物理化学性能,结果表明:当PVA掺量较少时,PVA形成丝状聚合物膜均匀分散于水泥砂浆中,填充孔洞和桥接裂缝,改善了水泥砂浆的微细观结构;但是,当 PVA掺量过多时会在水泥浆体内形成大量片状结构,包裹水泥颗粒和水泥水化产物,阻碍水泥的水化速度,导致改性砂浆的力学强度降低.%The effect of polyvinyl alcohol (PVA) on the mechanical properties of carbon black modi‐fied cement mortar was investigated .Results show that the compressive strength ,flexural strength and felt‐bending strength of modified cement mortar increase 32 .1% ,12 .2% and 18 .6% when 0 .2%PVA is incorporated .Fourier scanning electron microscope infrared spectrum ,X ray diffraction and differential scanning thermal analyzer were used to analyze the physical and chemical properties of modified cement mortar incorporating PVA ,and the results show that PVA polymer films bridging cracks w ere responsible for the considerable enhancement of mechanical properties w hen incorporated few PVA .However ,large amount of polymer films will be precipitated in the cement matrix when the mixing amount of PVA supersaturated ,and the main hydration products of cement will be reduced with the agglomeration of PVA films ,leading a low mechanical strength of cement mortar .

  20. Polymer and bitumen modified OPC for the immobilisation of ILW

    International Nuclear Information System (INIS)

    A detailed study has been made of the modification of ordinary Portland cement with polymeric additives, and of the properties of waste forms based on these matrix materials. The additives were styrene butadiene and bitumen emulsions, and epoxide and polyurethane resins: the simulated wastes were organic ion exchanger beads, PWR evaporator concentrate, reprocessing concentrate and Magnox metal. The effect of polymer:cement (p:c) and water:cement ratios on the properties of the hardened cement paste has been comprehensively investigated. Substantial increases in strain to failure, and modest reductions in permeability to water and leach rates for 137Cs, are obtained at p:c >= 0.2. Much larger volume fractions of organic ion exchange beads can be encapsulated in polymer modified OPC than in unmodified OPC, perhaps because of their better strain capability. The radiation stability of cemented PWR evaporator concentrate is better for a polymer modified matrix than an unmodified OPC matrix. Two hundred litre trials have been successfully demonstrated. (author)

  1. 纤维水泥砂浆与混凝土界面黏结性能钻芯拉拔试验研究%Core drilling and pull-off tests of interfacial bond behaviors between fiber cement mortar and concrete

    Institute of Scientific and Technical Information of China (English)

    卜良桃; 周云鹏

    2016-01-01

    To investigate the interfacial bond behaviors between fiber cement mortar and concrete with core drilling and pull⁃off tests, medium⁃sized columnar concrete samples enclosed with different strengths of polyvinyl alcohol fiber cement mortar, polypropylene fiber cement mortar, and steel fiber cement mortar were prepared. Core drilling and pull⁃off tests were conducted on the samples to obtain the pulling force with failure occurring at the interface, and the results of different kinds of samples from pull⁃off tests were compared with the axial tensile strength of concrete and compressive strength of fiber cement mortar. The results show that the interfacial bond strength between synthetic fiber cement mortar and concrete is higher than that between steel fiber cement mortar and concrete, and that the interfacial bond strength is positively correlated with the axial tensile strength of concrete and compressive strength of fiber cement mortar. There is also a linear correlation between the interfacial bond strength and compressive strength of fiber cement mortar.%为研究纤维水泥砂浆与混凝土界面黏结性能,采用钻芯拉拔法试验制作模拟中型柱混凝土构件,并分别外包不同强度的聚乙烯醇纤维水泥砂浆、聚丙烯纤维水泥砂浆、钢纤维水泥砂浆。对制作的试验构件进行钻芯拉拔试验,得出界面破坏时的拉拔力,将得到的不同类型的纤维水泥砂浆构件拉拔力数据与构件混凝土轴心抗拉强度、纤维水泥砂浆抗压强度进行比较分析。结果表明,在该试验中合成纤维水泥砂浆的界面黏结强度比钢纤维水泥砂浆的界面黏结强度高;界面黏结强度与构件混凝土轴心抗拉强度呈正相关关系,与纤维水泥砂浆抗压强度呈正相关关系,界面黏结力与砂浆抗压强度呈线性相关关系。

  2. 多孔集料砂浆的吸波特性%Absorbing Properties of Cement Mortar Filled with Porous Aggregates

    Institute of Scientific and Technical Information of China (English)

    李宝毅; 段玉平; 刘顺华

    2011-01-01

    对发泡聚苯乙烯、膨胀珍珠岩、页岩陶粒等3种多孔集料填充水泥基复合材料的电磁波吸收性能进行了研究。结果表明:多孔集料提高了复合材料与自由空间的波阻抗匹配程度,还可引起电磁波多次反射和散射,从而使电磁波迅速衰减;多孔集料填充率、集料种类、集料粒径等对电磁波吸收性能有显著影响;选用的多种集料中发泡聚苯乙烯对复合材料吸波性能的改善最为明显,当发泡聚苯乙烯粒径为2mm、与水泥体积比为1:l时,试样在4.5GHz处有最小反射率-18dB,且小于-10dB的吸收带宽达8.1GHz。%The absorbing properties of cement mortar filled with porous aggregates, such as expanded polystyrene, expanded perlite and shale, were investigated. The results show that porous aggregates can improve the impedance matching characteristic of the composites, and attenuate the electromagnetic wave by mulitple scattering and reflection. The filling ratio, the type and the size of porous aggregates all had effects on the absorbing properties. Among the aggregates used, the expanded polystyrene (EPS) had a superior ability to improve the absorbing properties of cement composite. When the filling ratio of EPS with the size of 2 mm to cement was 1:1 in volume, the lowest reflectivity of-18 dB was obtained at 4.5 GHz and the bandwidth less than -10 dB was 8.1 GHz.

  3. ASSESSMENT OF FINE RECYCLED AGGREGATES IN MORTAR

    OpenAIRE

    Feys, Charles; Joseph, Miquel; Boehme, Luc; Zhang, Yunlian

    2016-01-01

    In this study, the influence of fine recycled concrete aggregates as replacement for sand in mortar and the use as cement replacement and filler is investigated. Mortar with fine recycled aggregates is examined on its mechanical and physical properties. The samples are also examined on a microscopic scale. The fine recycled concrete aggregates are made with one-year old concrete made in the laboratory. Fine recycled aggregates (FRCA) are added as a cement replacement (0 %, 10 %...

  4. Generic OPC UA Server Framework

    Science.gov (United States)

    Nikiel, Piotr P.; Farnham, Benjamin; Filimonov, Viatcheslav; Schlenker, Stefan

    2015-12-01

    This paper describes a new approach for generic design and efficient development of OPC UA servers. Development starts with creation of a design file, in XML format, describing an object-oriented information model of the target system or device. Using this model, the framework generates an executable OPC UA server application, which exposes the per-design OPC UA address space, without the developer writing a single line of code. Furthermore, the framework generates skeleton code into which the developer adds the necessary logic for integration to the target system or device. This approach allows both developers unfamiliar with the OPC UA standard, and advanced OPC UA developers, to create servers for the systems they are experts in while greatly reducing design and development effort as compared to developments based purely on COTS OPC UA toolkits. Higher level software may further benefit from the explicit OPC UA server model by using the XML design description as the basis for generating client connectivity configuration and server data representation. Moreover, having the XML design description at hand facilitates automatic generation of validation tools. In this contribution, the concept and implementation of this framework is detailed along with examples of actual production-level usage in the detector control system of the ATLAS experiment at CERN and beyond.

  5. Changes in constituent equilibrium leaching and pore water characteristics of a Portland cement mortar as a result of carbonation.

    Science.gov (United States)

    Garrabrants, A C; Sanchez, F; Kosson, D S

    2004-01-01

    Two equilibrium-based characterization protocols were applied to ground samples of a cement-based material containing metal oxide powders in both noncarbonated and carbonated states. The effects of carbonation were shown through comparison of (i) material buffering capacity, (ii) constituent equilibrium as a function of leachate pH, and (iii) constituent solubility and release as a function of liquid-to-solid (LS) ratio. As expected, the material alkalinity was significantly neutralized during carbonation. In addition, carbonation of the cement material led to the formation of calcium carbonate and a corresponding increase in arsenic release across the entire pH range. The solubility as a function of pH for lead and copper was lower in the alkaline pH range (pH>9) for carbonated samples compared with the parent material. When solubility and release as a function of LS ratio was compared, carbonation was observed to decrease calcium solubility, sodium and potassium release, and ionic strength. In response to carbonate solid formation, chloride and sulfate release as a function of LS ratio was observed to increase. Trends in constituent concentration as a function of LS ratio were extrapolated to estimate pore water composition at a 0.06 mL/g LS ratio. Significant differences were observed upon comparison of estimated pore water composition to leachate concentrations extracted at LS ratio of 5 mL/g. These differences show that practical laboratory extractions cannot be assumed directly representative of pore water concentrations.

  6. Effect of gypsum content on sulfoaluminate mortars stability

    OpenAIRE

    DESBOIS, Tiffany; Le Roy, Robert; PAVOINE, Alexandre; PLATRET, Gérard; FERAILLE-FRESNET, Adélaïde; ALAOUI, Amina

    2010-01-01

    Calcium sulfoaluminate clinker is one of the most promising cements that would lower the greenhouse gas effect accompanying cement production. This article examines the effect of gypsum content on the dimensional stability of sulfoaluminate mortars. Mechanical properties as chemical evolution are studied. Our results show that the mortar with the greatest gypsum content expands without a decrease of its mechanical properties when it is cured in water. Two hypotheses about the mortars hydratio...

  7. 一种外掺新型引气剂的水泥胶砂抗折强度试验研究%A Study on the Bending Strength Test of Cement Mortar Added in a New Type of Air Entraining Agent

    Institute of Scientific and Technical Information of China (English)

    李铁军; 郭红兵

    2014-01-01

    In order to improve the mechanical property of cement mortar, admixtures are pro-posed to be put into cement mortar by adding air-entraining agent separately or mixing air en-training agent and water-reducing agent. The bending strength test of cement mortar has been done. The best model and the optimal dosage of air entraining agent in cement mortar have been determined for its optimal mechanical property. The result shows that the bending strength of cement mortar is significantly greater when air entraining agent and water-reducing agent are mixed. 2 # air-entraining agent has better effect in meeting the requirements of the bending strength of cement mortar.%为了提高水泥胶砂的力学性能,提出在水泥胶砂中掺加外加剂的方法,通过在水泥胶砂中单掺引气剂、复掺引气剂与减水剂两种途径,进行水泥胶砂抗折强度检测试验,对比确定水泥胶砂力学性能最优的引气剂型号及其最佳掺量。结果表明:引气剂与减水剂复掺时水泥胶砂的抗折强度明显大于引气剂单掺时水泥胶砂的抗折强度,2#引气剂最能满足水泥胶砂抗折强度要求。

  8. 微生物水泥砂浆的强度及耐久性试验研究%EXPERIMENTAL STUDY OF STRENGTH AND DURABILITY OF MICROBIAL CEMENT MORTAR

    Institute of Scientific and Technical Information of China (English)

    谭谦; 郭红仙; 程晓辉

    2015-01-01

    The bacteria Sporosarcina pasteurii ( S.p ) solution and the urease of S.p was added into the cement mortar.The urea-calcium acetate solution, bacterial culture medium and water were used to cure specimens.The uniaxial compressive test, the split tensile strength test and freeze-thaw cycling test were carried out to study the changes of their strength and durability .The mercury intrusion porosimeter was used to understand the microstructure of microbial cement mortar.The results showed that the microbial cement mortar had an increase in strength, the highest compressive strength increased by 47.22%, the highest tensile strength increased by 60.39%.In addition, the microbial cement mortar specimen cured in water had an excellent performance in freeze-thaw cycle test.%以添加巴氏芽孢八叠球菌或其脲酶的水泥砂浆试块为研究对象,分别使用营养液(尿素-乙酸钙溶液)、细菌培养液和水对水泥砂浆试块进行养护,通过单轴抗压强度、劈裂抗拉强度和冻融循环等试验研究其强度和耐久性的变化,并通过压汞试验研究其微观孔隙结构。结果表明:添加微生物后,水泥砂浆的抗压和抗拉强度都有提高,抗压、抗拉强度提高最多的分别是对照组的1.47倍和1.60倍;添加菌液在水中养护的水泥砂浆试块的抗冻融能力有较大提高。

  9. Effect of Fly Ash and Silica Fume on Hydration Rate of Cement Pastes and Strength of Mortars

    Institute of Scientific and Technical Information of China (English)

    LIU Jun; ZHANG Yun; LIU Runqing; ZHANG Bing

    2014-01-01

    The effect of fly ash and silica fume on hydration rate and strength of cement in the early stage was studied. Contrast test was applied to the complex cementitious system to investigate the hydration rate. Combined with mechanical strength, the influence of fly ash and silica fume during the hydration process of complex binder was researched. The peak of the rate of hydration heat evolution and the mechanical strength decreased as the ratio of fly ash increased, however, as the ratio of silica fume increased, the peak of the rate of hydration heat evolution and the mechanical strength increased obviously. When the ratios of fly ash and silica fume are 10%and 5%, the peak of the rate of hydration heat evolution is the highest. At the same time 7 days of flexural and compressive strength are the highest as 8.89 MPa and 46.52 MPa, respectively. Fly ash and silica fume are the main factors affecting the hydration rate and the mechanical property.

  10. Use of disposed waste ash from landfills to replace Portland cement.

    Science.gov (United States)

    Rukzon, Sumrerng; Chindaprasirt, Prinya

    2009-09-01

    In this study, waste ash was utilized as a pozzolanic material in blended Portland cement in order to reduce negative environmental effects and landfill volume required to dispose of waste ash. The influence of waste ash, namely palm oil fuel ash, rice husk ash and fly ash on compressive strength and sulfate resistance in mortar were studied and evaluated by some accelerated short-term techniques in sodium sulfate solutions. Ordinary Portland cement (OPC) was partially replaced with ground palm oil fuel ash (POA), ground rice husk ash (RHA) and classified fly ash (FA). Single pozzolan and a blend of equal weight portions of POA, RHA and FA were also used. The resistance to sulfate attack of mortar improves substantially with partial replacement of OPC with POA, RHA and FA. The use of a blend of equal weight portions of FA and POA or RHA produced mixes with good strength and resistance to sulfate attack. POA, RHA and FA have a high potential to be used as a pozzolanic material.

  11. Auxiliary pattern for cell-based OPC

    Science.gov (United States)

    Kahng, Andrew B.; Park, Chul-Hong

    2006-10-01

    The runtime of model-based optical proximity correction (OPC) tools has grown unacceptably with each successive technology generation, and has emerged as one of the major bottlenecks for turnaround time (TAT) of IC data preparation and manufacturing. The cell-based OPC approach improves runtime by performing OPC once per cell definition as opposed to once per cell instantiation in the layout. However, cell-based OPC does not comprehend inter-cell optical interactions that affect feature printability in a layout context. In this work, we propose auxiliary pattern-enabled cell-based OPC which can minimize the CD differences between cell-based OPC and model-based OPC. To enable effective insertion of auxiliary pattern (AP) in the design, we also propose a post-placement optimization of a standard cell block with respect to detailed placement. By dynamic programming-based placement perturbation, we achieve 100% AP applicability in designs with placement utilizations of cell-based OPC with AP can match gate edge placement error (EPE) count of model-based OPC within 4%. This is an improvement of 90%, on average, over cell-based OPC without APs. The AP-based OPC approach can reduce OPC runtimes versus model-based OPC by up to 40X in our benchmark designs. We can also achieve reduction of GDSII file size and ORC runtimes due to hierarchy maintenance of cell-based OPC.

  12. Effect of additives on the performance of recycled fine aggregate cement mortar%外加剂对再生细骨料水泥砂浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    王复星; 李国忠; 陈娟

    2014-01-01

    The effect of additives on the mechanical properties and water resistance of recycled fine aggregate cement mortar is studied. The result shows that the 28d flexural strength, compressive strength and osmotic pressure of cement mortar samples compared with the blank sample are increased by15.6%, 35.5%, 41.1%when silicone waterproofing agent is 0.2wt%, naphdalin series water reducer is wt1.0%,polycarboxylate super plasticizer is 0.8wt%.%研究了外加剂对再生细骨料水泥砂浆力学性能、防水性能的影响。结果表明:当有机硅防水剂掺量0.2 wt%、萘系减水剂1.0 wt%、聚羧酸减水剂0.8 wt%时,水泥砂浆试样与空白试样相比,其28 d抗折强度、抗压强度、渗透压力分别提高15.6%、35.5%、41.1%。实验中利用SEM对砂浆试样断面微观形貌进行了观察分析,同时利用XRD对水化产物进行了物相鉴定。

  13. The performance of mortar containing added metakaolin regarding sulfate action

    Directory of Open Access Journals (Sweden)

    Janneth Torres Agredo

    2010-04-01

    Full Text Available This paper evaluates the performance of adding Colombian metakaolin (MK to mortar when these are submitted to sulphate action. Four proportions of MK were used as cement replacement in this study: 10%, 20%, 35% and 50% by weight of cement; cement having 11% tricalcium aluminate was used. Mortar specimens were immersed in 5% sodium sulphate solution for a total period of 280 days after the specified initial moist curing period, The degree of sulphate attack was evaluated by measuring the mortar’s cylindrical expansion, mortar cubes’ compressive strength reduction and visual inspection of mortar specimens. An additional study using X-ray diffraction was conducted to determine the products formed in the cement pastes due to the sulphate attack. The results showed that MK mortar sulphate resistance increased when increasing MK replacement level. An MK proportion greater than 20% is re-commended for obtaining better performance against sulphate attack.

  14. Quantitative microstructure analysis of polymer-modified mortars.

    Science.gov (United States)

    Jenni, A; Herwegh, M; Zurbriggen, R; Aberle, T; Holzer, L

    2003-11-01

    Digital light, fluorescence and electron microscopy in combination with wavelength-dispersive spectroscopy were used to visualize individual polymers, air voids, cement phases and filler minerals in a polymer-modified cementitious tile adhesive. In order to investigate the evolution and processes involved in formation of the mortar microstructure, quantifications of the phase distribution in the mortar were performed including phase-specific imaging and digital image analysis. The required sample preparation techniques and imaging related topics are discussed. As a form of case study, the different techniques were applied to obtain a quantitative characterization of a specific mortar mixture. The results indicate that the mortar fractionates during different stages ranging from the early fresh mortar until the final hardened mortar stage. This induces process-dependent enrichments of the phases at specific locations in the mortar. The approach presented provides important information for a comprehensive understanding of the functionality of polymer-modified mortars.

  15. Potencialidades de um caulim calcinado como material de substituição parcial do cimento portland em argamassas Potentialities of a calcined kaolin as material of partial replacement of portland cement in mortars

    Directory of Open Access Journals (Sweden)

    Marilia P. de Oliveira

    2006-06-01

    Full Text Available A utilização de argilas calcinadas na forma de metacaulinita, como material pozolânico para argamassas e concretos, tem recebido atenção considerável nos últimos anos. Este trabalho objetivou avaliar o desempenho mecânico de argamassas, nas quais foi utilizado um caulim calcinado proveniente do Estado da Paraíba, como material de substituição parcial do cimento Portland. Utilizaram-se duas finuras do caulim: passando nas peneiras ABNT 200 (0,074 mm e 325 (0,044 mm e calcinados nas temperaturas de 700, 800 e 900 ºC pelo tempo de 2 h. As amostras foram caracterizadas através de análise química, análise térmica diferencial, difração de raios-X e área específica. Obteve-se o índice de atividade pozolânica com a cal e o cimento Portland. O percentual de substituição adotado foi de 0, 10, 20, 30 e 40%. A relação aglomerante: areia foi de 1:1,5 e a relação água/aglomerante fixada igual 0,4. O efeito da substituição parcial do cimento na argamassa foi avaliado através da resistência à compressão simples, nas idades de 7, 28 e 90 dias. As argamassas estudadas apresentaram resistência superior em relação à da referência, até o nível de 30% de substituição.The use of burnt clays, in the metakaolin form, as pozzolanic material for mortars and concretes has received a remarkable attention in the last years. This paper aimed to evaluate the mechanical property of mortars, in which a calcined kaolin originating from the State of Paraiba, was used as partial cement replacement material. Two finess of the kaolin were used: ABNT 200 (0.074 mm and 325 (0.044 mm and burnt at temperatures of 700, 800 and 900 ºC for a period of 2 h. Both materials were characterized by chemical analysis, differential thermal analysis, X-ray diffraction, specific area tests. The pozolanic activity index was obtanied using lime and cement Portland. The amounts of replacement were 10, 20, 30 and 40%, besides the reference mortar. The binder

  16. Effects of Ethylene/Vinyl Chloride/Vinyl Laurate Redispersible Terpolymer on Pore Structure and Properties of Cement Mortar%E/VC/VL三元共聚物对水泥砂浆孔结构和性能的影响

    Institute of Scientific and Technical Information of China (English)

    张国防; 王培铭

    2013-01-01

    Effects of ethylene/vinyl chloride/vinyl laurate redispersible terpolymer(E/VC/VL) on the pore structure of cement mortar were studied through mercury intrusion porosimeter(MIP) and environmental scanning electron microscopy(ESEM). The relationships between the pore structure and the properties of cement mortar were also discussed. The results show that E/VC/VL remarkably affects the pore structure of cement mortar. E/VC/VL definitely increases the total pore volume, porosity and the average pore radius. E/VC/VL significantly increases the content of large capillary pores of cement mortar, which distribute in the C-S-H gel. With the increase of its use level, the effect of E/VC/VL on the pore structure of cement mortar is enhanced. As the porosity and the total pore volume of cement mortar modified with E/VC/VL increases, the bulk density and the compressive strength of cement mortar decrease, but the water permeation resistance is greatly enhanced.%利用压汞法和环境扫描电子显微镜分析方法,研究了乙烯/氯乙烯/月桂酸乙烯酯(E/VC/VL)三元共聚物对水泥砂浆孔结构的影响规律,并探讨了其与水泥砂浆的体积密度、抗压强度、抗水渗性、吸水量和吸水率等宏观性能的关系.研究表明:E/VC/VL三元共聚物能显著影响水泥砂浆的孔结构,增大水泥砂浆的孔隙率、总孔体积和平均孔半径;导致大毛细孔显著增多,且密布在C-S-H凝胶之间.E/VC/VL三元共聚物掺量越大,对水泥砂浆孔结构的影响越显著.E/VC/VL三元共聚物改性水泥砂浆的孔隙率和孔体积与宏观性能之间存在密切关系:孔隙率和孔体积越大,水泥砂浆的体积密度和抗压强度越小,但其抗水分渗透性能则越好.

  17. Study on properties of cement mortar mixed with powdered slag & flyash%掺矿渣微粉和粉煤灰的水泥胶砂性能试验研究

    Institute of Scientific and Technical Information of China (English)

    杨华全; 覃理利; 董维佳; 王仲华

    2001-01-01

    Based on orthogonal design method,the orthogonal list L24(61×41×23) was selected for arranging test,the influences of the quantity of pozzolanic admixture,the ratio of powdered slag and flyash,the fineness of powdered slag,and the quality of flyash on the flowabilities,the compressive and flexural strengths of cement mortar at ages of 7,28,90 and 180 days,respectively,were explored.On the basis of experimental tests,the optimum combination of cement,powdered slag and flyash was determined. The test results showed that the cement mortar containg powdered slag and flyash is better than that only mixing with either powdered slag or flyash.%根据正交设计法,利用L24(61×41×23)正交表安排试验,探讨了混合材掺量、矿渣微粉与粉煤灰的比例、矿渣微粉细度、粉煤灰品种对水泥胶砂流动度、7,28,90 d龄期的抗压强度的影响,初步确定水泥熟料、矿渣微粉、粉煤灰三元体系的较优组合。结果表明,粉煤灰与矿渣微粉双掺比单掺矿渣微粉或单掺粉煤灰的水泥胶砂,具有一定的优势。

  18. Strength and Drying Shrinkage of Alkali-Activated Slag Paste and Mortar

    Directory of Open Access Journals (Sweden)

    Mao-chieh Chi

    2012-01-01

    Full Text Available The aim of this study is to investigate the strengths and drying shrinkage of alkali-activated slag paste and mortar. Compressive strength, tensile strength, and drying shrinkage of alkali-activated slag paste and mortar were measured with various liquid/slag ratios, sand/slag ratios, curing ages, and curing temperatures. Experimental results show that the higher compressive strength and tensile strength have been observed in the higher curing temperature. At the age of 56 days, AAS mortars show higher compressive strength than Portland cement mortars and AAS mortars with liquid/slag ratio of 0.54 have the highest tensile strength in all AAS mortars. In addition, AAS pastes of the drying shrinkage are higher than AAS mortars. Meanwhile, higher drying shrinkage was observed in AAS mortars than that observed comparable Portland cement mortars.

  19. The shrinkage in lime mortars

    Directory of Open Access Journals (Sweden)

    Sánchez, J. A.

    1997-03-01

    Full Text Available Nowadays, the methodology existing to measure the shrinkage in air, developed for paste and cement mortars, has serious problems to be applied to lime mortars, due to its different mechanism of hardening several modifications in Norms UNE 80-113-86 y 80-112-89 make possible the determination of the shrinkage in these traditional mortars.

    La metodología existente en la actualidad para la medida de la retracción de secado, desarrollada para las pastas y los morteros de cemento, presenta serios problemas a la hora de su aplicación a los morteros de cal debido a su distinto mecanismo de endurecimiento. Algunas modificaciones de las normas UNE 80-113-86 y 80-112-89 hacen posible la determinación de la retracción en estos morteros tradicionales.

  20. 高性能混凝土外加剂对水泥砂浆力学性能的影响%Mechanical properties research of high-performance concrete admixtures on the cement mortar

    Institute of Scientific and Technical Information of China (English)

    程朝霞; 张自新; 胡志超; 杨健辉

    2011-01-01

    A new type of admixtures on mortar strength was researched with mixed-level orthogonal table.Mixing a few different factors and levels of additives to form a new group of 16 specimens of cement mortar,and testing 3 d and 28 d strength of these prism specimens,then using orthogonal design analysis of variance test methods such as error analysis researched the influence of high-performance concrete admixtures on the cement mortar strength.The results showed that high-performance concrete admixtures are not the most perfect additives.Without reducing water consumption,high performance concrete admixtures with the same quality of cement replacement,the admixtures on the strength of the effect is not significant factors.In the dosage less case,the improvement is not obvious on the strength of concrete,and mixed with excessive can cause retardation.Admixture of polycarboxylate superplasticizer increases the strength.There was an interaction between high-performance concrete admixtures and water reducing agent.%采用混合水平正交表研究了新型外加剂对砂浆强度的影响.通过掺加不同因子及水平数的新型外加剂成型了16组水泥砂浆试件,测试了3 d和28 d龄期的强度,采用正交设计中的方差分析、试验误差等方法分析表明,高性能混凝土外加剂并不是性能最好的外加剂,不减少用水量的情况下,用高性能混凝土外加剂替代同等质量水泥后,外加剂对强度的影响并不是显著因素.掺量较少的情况下,对混凝土强度的提高不明显,掺量过大,会造成缓凝.掺加聚羧酸减水剂提高强度,高性能混凝土外加剂和减水剂之间存在交互作用.

  1. Role of different superplasticizers on hydrated lime pastes and mortars

    OpenAIRE

    Alvarez, J. I.; Fernandez, J M; Sirera, R. (Rafael); Perez-Nicolas, M. (María); Navarro-Blasco, I. (Íñigo); Duran, A

    2015-01-01

    The behaviour of different superplasticizers admixtures was assessed for hydrated lime pastes and mortars. Sometimes, air lime pastes and mortars were modified with two supplementary cementing materials (SCMs), namely nanosilica (NS) and metakaolin (MK). Two different polycarboxylate ethers, a lignosulfonate and a naphthalene condensed sulfonate superplasticizer were added to lime pastes and mortars and their effects on fresh-state properties as well as on the mechanical strengths were evalua...

  2. 砂浆板冲击破坏试验研究%Damage tests for a cement mortar plate under shock load

    Institute of Scientific and Technical Information of China (English)

    顾培英; 邓昌; 章道生; 汤雷; 王建

    2015-01-01

    通过锤击、均匀冲击荷载试验,采用逐级递增循环冲击加载方式,研究冲击荷载下砂浆板的破坏特征及冲击力、冲击能与最大加速度响应间关系。试验表明,二种冲击作用均使砂浆板跨中区域出现贯穿裂缝,呈脆性劈裂破坏形态,均匀冲击作用下破坏位置与跨中有一定偏移;锤击力时程经历主冲击、次冲击、卸载三阶段,加速度响应随锤击力增加而增加,裂缝贯穿后冲击力、加速度响应大幅减小;均匀冲击下加速度有二组响应区,响应随冲击能增加而增加,当冲击能达一定程度时响应大幅减小;继续增加冲击能,响应又会增加,并较快发生劈裂破坏,响应大幅减小;支座螺栓松动能缓冲部分冲击作用。%Hammering and uniform shock tests of a cement mortar plate were conducled.The opposite sides of the plate were elastic supports.Through cyclic shocks with amplitude increasing,the failure features,the relationship between shock force and acceleration response,and the relationship between impact energy and acceleration response of the plate were studied.The results showed that a transverse crack nearby the midspan of the plate appears,its failure state is brittle splitting;the location of failure offsets the midspan under uniform shock;time history curves of the hammering force include three stages of major shock,secondary shock and unloading;the acceleration response of the plate increases with increase in the hammering force,however,the hammering force and acceleration response decrease obviously after the transverse crack appears;there are two groups of acceleration response regions under uniform shock;the acceleration response increases with increase in impact energy;once impact energy reaches a certain level,the acceleration response decreases obviously;if impact energy continuously increases,the acceleration response increases again,brittle splitting failure occurs

  3. Corrosion performance of reinforced mortar in the presence of polymeric nano-aggregates: electrochemical behavior, surface analysis, and properties of the steel/cement paste interface

    NARCIS (Netherlands)

    Hu, J.; Koleva, D.A.; Van Breugel, K.

    2012-01-01

    This study reports on the effect of admixed polyethylene oxide-b-polystyrene (PEO113-b-PS70)micelles on corrosion behavior of reinforced mortar. The electrochemical measurement shows that the corrosion performance of the reinforcing steel was not significantly improved. However, surface analysis and

  4. Swine deep bedding ashes as a mineral additive for cement based mortar Cinzas de cama sobreposta de suínos como adição mineral em argamassas de cimento

    Directory of Open Access Journals (Sweden)

    Melissa Selaysim Di Campos

    2008-04-01

    Full Text Available The sustainability of intensive swine production demands alternative destinations for the generated residues. Ashes from swine rice husk-based deep bedding were tested as a mineral addition for cement mortars. The ashes were obtained at 400 to 600ºC, ground and sieved through a 325 mesh sieve (# 0.045 mm. The characterization of the ashes included the determination of the index of pozzolanic activity with lime. The ashes were also tested as partial substitutes of Portland cement. The mortars were prepared using a cement:sand proportion of 1:1.5, and with water/cement ratio of 0.4. Three percentages of mass substitution of the cement were tested: 10, 20 and 30%. Mortar performances were assessed at 7 and 28 days determining their compressive strength. The chosen condition for calcinations at the laboratory scale was related to the maximum temperature of 600ºC since the resulting ashes contained vitreous materials and presented satisfactory values for the pozzolanic index under analysis. The pozzolanic activity indicated promising results for ashes produced at 600ºC as a replacement of up to 30% in cement masses.A sustentabilidade das regiões de produção intensiva de suínos requer destinos alternativos para os resíduos gerados. Cinzas de cama sobreposta de suínos à base casca de arroz, foram testadas como adição mineral em substituição ao cimento. As cinzas foram obtidas nas temperaturas de 400 a 600ºC, moídas e passadas por peneira ABNT 325 (# 0,045 mm. A caracterização de cinzas incluiu a determinação do índice de atividade pozolânica com a cal. As cinzas também foram testadas como substitutos parciais de cimento Portland. As argamassas foram preparadas na proporção cimento:areia de 1:1,5 e com fator água-cimento de 0,4. Três porcentagens de substituição do cimento comercial foram usadas: 10, 20 e 30% em massa. O desempenho das argamassas foi avaliado aos 7 e aos 28 dias com a determinação da resistência

  5. 不同含气量水泥砂浆孔体积分形维数研究%Study on Pore Volume Fractal Dimension for Cement Mortar with Different Air Contents

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    The pore structure parameters of cement mortar with different air contents are measured by mercury porosimeter and pore structure analyzer. Fractal model based on thermodynamic method is used in calculation of different scales' pore structure fractal dimensions of cement mortar. The relationships between fractal dimension and porosity, average pore diameter, pore specific surface area, pore spacing coefficient, total pore volume of cement mortar are analyzed. The result shows that ( 1 ) the fractal dimension of pore structures with different scales calculated by the fractal model based on thermodynamics presents multiplicity, it can represent the complexity of cement mortar pore structure very well; ( 2 ) the increase of air content makes the fractal dimension of the pore whose diameter is more than the range of 102 nm has increase trend, while the fractal dimension of the pore whose diameter is under the range of 102 nm shows a trend of decrease; (3) the increase of age makes the fractal dimension of the pore whose diameter is in the range of 103 nm to 104 nm shows a trend of decrease, the others shows a trend of increase; (4) among the pore structure parameters, the pore volume fractal dimension has good correlation with porosity, average pore diameter and total pore volume, and has poor correlation with pore specific surface area in the range of 103 -104 nm and 102 -103 nm pore diameters. Considering the pores whose diameters in the range of 102 -103 nm have a high proportion in the total pore, it can be as a unified fractal dimension to signify the change of pore structure parameters.%采用压汞仪、气孔结构分析仪测定了不同含气量水泥砂浆的孔结构参数,通过热力学关系的分形模型计算得到了水泥砂浆不同尺度孔结构分形维数,并分析了水泥砂浆不同尺度孔结构孔体积分形维数与孔隙率、平均孔径、孔比表面积、孔间距系数、孔总体积关系.结果表明:基于热力学关系的分

  6. Water extraction out of mortar during brick laying. An NMR study

    NARCIS (Netherlands)

    Brocken, H.J.P.

    1996-01-01

    The water extraction out of mortar during brick laying was studied by nuclear magnetic resonance. The water extraction is an important parameter that determines, e.g., the stiffness of the mortar due to compaction of the cement particles and the bond strength of the cured-mortar interfaces but allo

  7. Self healing phenomena in concretes and masonry mortars: A microscopic study

    NARCIS (Netherlands)

    Nijland, T.G.; Larbi, J.A.; Hees, R.P.J. van; Lubelli, B.A.; Rooij, M.R. de

    2007-01-01

    A microscopic survey of over 1000 of samples of concrete and masonry mortars from structures in the Netherlands shows that, in practice, self healing occurs in historic lime and lime – puzzolana mortars, in contrast to modern cement bound concretes and mortars. Self healing may be effected by the fo

  8. Durability of expanded polystyrene mortars

    OpenAIRE

    Ferrándiz Mas, Verónica; García Alcocel, Eva María

    2013-01-01

    The influence of the addition of various types and various concentrations of expanded polystyrene foam (both commercial and recycled) on the durability of Portland cement mortars is studied. In particular, the microstructure is studied utilizing the following methods: capillary absorption of water, mercury intrusion porosimetry, impedance spectroscopy and open porosity. In addition, the effects of heat cycles and freeze–thaw cycles on compressive strength are examined. Scanning electron micro...

  9. Salt resistant mortars: present knowledge and future perspectives

    NARCIS (Netherlands)

    Lubelli, B.

    2013-01-01

    Salt crystallization damage is one of the most common causes of decay for bedding, pointing and plastering mortar. Attempts to tackle the problem have been mainly focused on increasing the mechanical strength of the mortar, by the replacement of lime with (PTL) cement, or on reducing the moisture tr

  10. Salt resistant mortars: present knowledge and future perspectives

    NARCIS (Netherlands)

    Lubelli, B.A.

    2013-01-01

    Salt crystallization damage is one of the most common causes of decay for bedding, pointing and plastering mortar. Attempts to tackle the problem have been mainly focused on increasing the mechanical strength of the mortar by the replacement of lime with (PTL) cement, or on reducing the moisture tra

  11. Efeito da aplicação do poliestireno sulfonado (PSSNa como aditivo em argamassas e concretos de cimento Portland CPV32 Effect of PSSNa as admixture in mortars and concrete of cement portand CPV32

    Directory of Open Access Journals (Sweden)

    Betina Royer

    2005-03-01

    Full Text Available Neste trabalho foi investigado o uso do Poliestireno sulfonado (PSSNa, produzido a partir de copos plásticos descartáveis de Poliestireno (PS, como aditivo em argamassas e concretos de cimento Portland CPV32. A avaliação do PSSNa como aditivo foi baseada em ensaios de fluidez e resistência mecânica à compressão de corpos de prova. Foi observado, em argamassas com relação água/cimento (a/c de 0,48, um aumento na fluidez com o aumento das porcentagens de PSSNa (0,25 a 1,00%. A adsorção do PSSNa sobre as partículas de cimento melhora a dispersão dos componentes da argamassa, aumentando a resistência mecânica à compressão dos corpos de prova após a cura. A aplicação do PSSNa em concreto apresentou o mesmo efeito. O abatimento do concreto sem PSSNa foi de 50 mm, atingindo cerca de 200 mm com o uso do polieletrólito. Devido à elevada plasticização observada é possível empregar o PSSNa como aditivo redutor de água. Foi produzido um concreto com o mesmo abatimento da referência sem aditivo reduzindo-se a quantidade de água em 20,8%. O ganho de resistência mecânica à compressão obtido foi de 21,5 e 26,3 %, respectivamente aos 7 e 28 dias de cura. Estes resultados mostraram que soluções de PSSNa podem atuar eficientemente como aditivo superplastificante ou redutor de água em argamassas e concretos.In this work an investigation was made of the effects from adding PSSNa, obtained from disposable polystyrene (PS cups, as admixture agent in mortars and concrete with varying ratios from 0.25 to 1.00%. The evaluation of PSSNa as additive was based on results of fluidity and mechanical strength to compression. In mortars with water/cement ratio of 0.48, an increase in flow was observed when the dosage of PSSNa varied from 0.25 to 1.00%. The dispersion of mortar components was improved due to the adsorption of PSSNa on cement particles, which increased the mechanical strength of mortars. Similar results were obtained with the

  12. INFLUENCE OF GROUND MINERAL ADMIXTURES ON PORE STRUCTURE OF HARDENED CEMENT PASTE AND STRENGTH OF CEMENT MORTAR%磨细矿物掺合料对水泥硬化浆体孔结构及砂浆强度的影响

    Institute of Scientific and Technical Information of China (English)

    李永鑫; 陈益民

    2006-01-01

    采用压汞法研究了钢渣、矿渣、粉煤灰单掺或复掺对水泥硬化浆体孔结构的影响.同时还研究了掺合料单掺或复掺对水泥砂浆抗压强度的影响.结果表明:掺合料单掺或复掺对早期水泥硬化浆体的孔结构有一定的劣化作用;水化后期,矿渣与钢渣均明显降低了水泥硬化浆体的孔隙率,矿渣与粉煤灰均明显降低了水泥硬化浆体的中值孔径并改善了水泥石的孔径分布,掺合料复掺对改善水泥硬化浆体的孔结构有积极作用,尤其是掺合料三元复合可取得最佳的效果.3种掺合料降低水泥硬化浆体孔隙率能力的大小顺序为:矿渣>钢渣>粉煤灰.3种掺合料降低水泥硬化浆体孔径并改善孔径分布能力的大小顺序为:矿渣>粉煤灰>钢渣.掺合料降低了水泥砂浆早期的抗压强度,却增加了水泥砂浆90 d的抗压强度.掺合料的活性大小顺序为:矿渣>钢渣>粉煤灰.%The influence of singly and compositely adding steel slag, blast furnace slag and fly ash on the pore structure of handened cement paste was studied using mercury intrusion porosimetry (MIP). Furthermore, their influence on the compressive strength of cement mortar was also investigated. The results show that the pore structure of cement paste become worse at early ages by singly or compositely adding any of the mineral admixtures. At later ages, adding either blast furnace slag or steel slag remarkably reduces the porosity of cement paste, while either blast furnace slag or fly ash remarkably reduces median pore diameter and improves pore size distribution. The most reduction in the porosity of cement paste is observed for the cement with blast furnace slag, while the cement with steel slag less, and the cement with fly ash the least. The biggest improvement on pore structure is observed for the cement with blast furnace slag, while the cement with fly ash smaller, and the cement with steel slag the smallest. Pore structure

  13. Rendering mortars in Medina Azahara, Part I: Material characterization and alteration process

    OpenAIRE

    Blanco-Varela, M. T.; Puertas, F.; Palomo, A.

    1997-01-01

    Rendering mortars, which are still exposed to the open air on some of the walls of Medina Azahara, are studied and characterized in this work. Some repairing mortars used in different previous restorations are also characterized. Those rendering mortars are of different make considering the composition of their binder: lime, gypsum and mixed lime/ gypsum. Repairing mortars used in previous interventions are made of lime, excepting for a portland cement used by Félix Hernández in the rest...

  14. Sulfate and acid resistant concrete and mortar

    Science.gov (United States)

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1998-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance.

  15. The Aesthetical quality of SSA-containing mortar and concrete

    DEFF Research Database (Denmark)

    Kappel, Annemette; Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.;

    2014-01-01

    that gives a characteristic red colour. The process of grinding SSA has shown to improve the compressive strength of SSA- containing mortar (Donatello et al. 2010). Thus, in this study SSA was grinded in 6 different intervals ranging from 0 – 10 min, and then added to the mortar mix replacing 20% of cement....... The experiment revealed that the colour of the SSA-containing mortar intensified as the time interval of the grinding process increased. Each of the 6 steps within the time interval provided an additional colour tone and generated a colour scale consisting of mortar samples ranging from greyish to a more...

  16. The Effective Superiority of I Grade Fly Ash and Effects on the Strength of Cement Sand Mortar in Sanxia Engineering%三峡工程用Ⅰ级粉煤灰效应优势及其对水泥砂浆强度贡献

    Institute of Scientific and Technical Information of China (English)

    朱蓓蓉; 张树青; 吴学礼; 黄士元

    2001-01-01

    研究了三峡工程用Ⅰ级粉煤灰效应优势及其对水泥砂浆强度的贡献。结果表明:相比于Ⅱ级粉煤灰,Ⅰ级粉煤灰的火山灰活性未必更高,但Ⅰ级粉煤灰颗粒形态效应上的优势导致了其对水泥砂浆强度产生更明显的影响。%This paper studies the effective superiority of Ⅰ grade fly ash and effects on the strength of cement sand mortar in Sanxia engineering.The results show that compared with Ⅱ grade fly ash,Ⅰ grade fly ash is not certainly good in chemical reactivity,but its  advantage in shape effect is obvious to the strength of cement sand mortar.

  17. Effect of Crumb Rubber on Pore Structure of Cement Mortar%橡胶集料对水泥砂浆孔结构的影响

    Institute of Scientific and Technical Information of China (English)

    杨林虎; 朱涵; 张亚梅

    2011-01-01

    采用压汞法(MIP)测试了掺加橡胶集料的水泥砂浆的孔径分布和孔隙率,研究了橡胶集料对水泥砂浆孔结构的影响.通过橡胶集料含量与孔隙率和含气量之间的关系,分析了橡胶集料的引气作用.测试结果表明,掺入橡胶集料后,砂浆的最可几孔径、平均孔径、中值孔径以及孔隙率均增大,但砂浆的孔径分布趋于均匀.橡胶集料的引气作用随其含量的增加而增强.%In this paper, mercury intrusion porosimeter(MIP) was used to test pore size distribution and porosity of the mortar incorporating crumb rubber. The effect of crumb rubber on pore structure of mortar was investigated. The air-entraining ability of crumb rubber was analyzed based on the relationship between crumb rubber content and porosity and air content. The test results show that mode pore diameter, mean pore diameter, median pore diameter and porosity of the mortar increase after crumb rubber is incorporated, but the distribution of pore size reveals a uniform distribution tendency. The air-entraining ability of crumb rubber is enhanced as its content increases.

  18. 掺活化煤矸石粉、粉煤灰水泥砂浆抗压强度预测%Prediction of compressive strength of cement mortars with fly ash and activated coal gangue

    Institute of Scientific and Technical Information of China (English)

    周双喜; 陈益民; 张文生

    2006-01-01

    The pozzolanic activity of coal gangue, which is calcining at 500 to 1 000 ℃, differs distinctly. The simplex-centroid design with upper and lower bounds of component proportion is adopted to study the compressive strength of mortars made with ternary blends of cement, activated coal gangue and fly ash. Based on the results of a minimum of seven design points, three special cubic polynomial models are used to establish the strength predicating equations at different ages for mortars. Five experimental checkpoints were also designed to verify the precision of the equations. The most frequent errors of the predicted values are within 3%. A simple and practical way is provided for determining the optimal proportion of two admixtures when they are used in concrete.%煤矸石经不同的温度(500~1000 ℃)热活化后,其辅助胶凝性能相差很大.为了研究双掺活化煤矸石与粉煤灰对水泥强度性能的影响,运用单纯形-中心设计方法,并确立各组分的上下限,通过7组砂浆实验,得出活化煤矸石粉、粉煤灰多元复合水泥不同龄期强度数学模型,并利用5组砂浆实验,对强度预测方程的精确性进行了研究.实验结果表明方程的计算值与实验测量值相差很小,误差范围在3%以下.为配制多种混合材的复合水泥最优配比提供了一个简单实用的方法.

  19. High performance superplasticized silica fume mortars for ferrocement works

    Directory of Open Access Journals (Sweden)

    Rathish Kumar P.

    2010-01-01

    Full Text Available Ferrocement works demand cement mortars of good workability and high strength. Reduction in water-cement ratio combined with a refined pore structure increases the compressive strength in addition to the enhancement of durability characteristics, but the workability decreases. Workability becomes important, as the mortar has to easily penetrate between the layers of the mesh wires. A reasonably workable high strength cement mortar can be obtained by using a high cement content coupled with the use of superplasticizers. These were also found to retain the cohesiveness and check undesirable bleeding and segregation. An experimental program was conducted to study the functional efficacy of an SNF condensate used as a water reducing superplasticizer. The compressive strength and flow characteristics of the mortars were determined to decide their suitability for ferrocement works. The parameters included the mix proportions, the grade of cement, age of curing and the dosage of superplasticizer. It was concluded from the study that the addition of an optimum dosage of superplasticizer improved the workability and strength characteristics of silica fume mortars. There was a late gain in the compressive strength of silica fume mortars.

  20. Polymer and bitumen-modified OPC for the immobilization of ILW

    International Nuclear Information System (INIS)

    A detailed study has been made of the modification of ordinary Portland cement with polymeric additives, and of the properties of waste forms based on these matrix materials. The additives were styrene butadiene and bitumen emulsions, and epoxide and polyurethane resins: the simulated wastes were organic ion exchanger beads, PWR evaporator concentrate, reprocessing concentrate and Magnox metal. The effect of polymer: cement (p:c) and water:cement ratios on the properties of the hardened cement paste has been comprehensively investigated. Substantial increases in strain to failure, and modest reductions in permeability to water and leach rates for Cs137, are obtained at p:c > 0.2. Much larger volume fractions of organic ion exchange beads can be encapsulated in polymer modified OPC than in unmodified OPC, perhaps because of their better strain capability. The radiation stability of cemented PWR evaporator concentrate is better for a polymer-modified matrix than an unmodified OPC matrix. Two hundred litre trials have been successfully demonstrated. 20 refs, 20 tabs, 10 figs

  1. Effect of Binder’s Type on Physico-Mechanical and Thermal Properties of Mortars with a Basis of Coir

    Directory of Open Access Journals (Sweden)

    Athanas Konin

    2012-05-01

    Full Text Available This study aims to study the effect of type of binder on properties of mortars with coir. Two types of binders were used for the manufacturing of mortars containing coir: lime is used as binder for mortar nº1 (Mortar 1 and cement is used for mortar nº2 (Mortar 2. The measurements of the physical, mechanical and thermal properties of the specimens show that Mortar 1 has higher water absorption values than those of Mortar 2 and consequently has the lowest values of thermal conductivity. The results also indicate that dry density of the specimens has more important role than the type of binder on mechanical properties. Relationships were established between mechanical properties and dry density of these mortars. These relationships are independent to the type of binder. The mortars also satisfied most recommended thermal insulation standards.

  2. Properties of Rice Husk Ash (RHA and MIRHA Mortars

    Directory of Open Access Journals (Sweden)

    Narayanan Sambu Potty

    2014-05-01

    Full Text Available Rice husk Ash (produced by traditional burning called RHA and by using microwave incinerator called MIRHA has shown promise as a cement replacement material. This study investigated the properties of RHA and MIRHA mortar used for brick manufacture at binder sand proportions of 1:3 and 1:4. RHA and MIRHA were intermediate in particle size to cement and sand particles. Percentages of replacement were 5, 10, 15, 20, 25 and 30%, respectively. Strength at w/c ratios (0.5, 0.55, 0.6 and 0.65, respectively was investigated to identify optimum w/c ratios as well as optimum percent replacement of RHA and MIRHA. Variations of IRS, density and water absorption were investigated. Generally 1:3 RHA and 1:3 MIRHA mortars strength showed decreasing trend with increasing percentage replacement with RHA and MIRHA. Whereas 1:4 RHA and 1:4 MIRHA mortars showed increase in strength at 5% replacement and decrease thereafter. IRS values for RHA mortars are generally within limits (0.25-1.5 kg/m2.min recommended. Water absorption values of RHA mortars are generally higher than control mortar. IRS values for MIRHA mortars with w/c 0.5 and 0.55 ranged between 1.4-2.0 kg/m2 .min; indicating the need for wetting the bricks before use. IRS values for 1:3 MIRHA mortars with w/c 0.6 and 0.65 were below 1.0 kg/m2.min indicating low suction values. For 1:4 MIRHA mortars, IRS values were very low in all cases. Water absorption values of MIRHA mortars are generally higher than the control mortar. MIRHA mortars with w/c 0.6 and 0.65 showed low percentages of water absorption.

  3. MORTAR WITH UNSERVICEABLE TIRE RESIDUES

    Directory of Open Access Journals (Sweden)

    José Aparecido Canova

    2009-12-01

    Full Text Available This study analyzes the effects of unserviceable tire residues on rendering mortar using lime and washed sand at a volumetric proportion of 1:6. The ripened composite was dried in an oven and combined with both cement at a volumetric proportion of 1:1.5:9 and rubber powder in proportional aggregate volumes of 6, 8, 10, and 12%. Water exudation was evaluated in the plastic state. Water absorption by capillarity, fresh shrinkage and mass loss, restrained shrinkage and mass loss, void content, flexural strength, and deformation energy under compression were evaluated in the hardened state. There was an improvement in the water exudation and water absorption by capillarity and drying shrinkage, as well as a reduction of the void content and flexural strength. The product studied significantly aided the water exudation from mortar and, capillary elevation in rendering.

  4. MORTAR WITH UNSERVICEABLE TIRE RESIDUES

    Directory of Open Access Journals (Sweden)

    J. A. Canova

    2009-01-01

    Full Text Available This study analyzes the effects of unserviceable tire residues on rendering mortar using lime and washed sand at a volumetric proportion of 1:6. The ripened composite was dried in an oven and combined with both cement at a volumetric proportion of 1:1.5:9 and rubber powder in proportional aggregate volumes of 6, 8, 10, and 12%. Water exudation was evaluated in the plastic state. Water absorption by capillarity, fresh shrinkage and mass loss, restrained shrinkage and mass loss, void content, flexural strength, and deformation energy under compression were evaluated in the hardened state. There was an improvement in the water exudation and water absorption by capillarity and drying shrinkage, as well as a reduction of the void content and flexural strength. The product studied significantly aided the water exudation from mortar and, capillary elevation in rendering.

  5. 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.

  6. Mortar and concrete based on calcium sulphate binders

    NARCIS (Netherlands)

    Bakker, J.J.F.; Brouwers, H.J.H.

    2006-01-01

    In this study both hemi-hydrate and anhydrite are tested as calcium sulphate binders for structural mortar and concrete. The advantage of using calcium sulphates instead of cement as a binder is the fact that the production of calcium sulphate is more environmental friendly than that of cement. For

  7. Characterization and Degradation of Masonry Mortar in Historic Brick Structures

    Directory of Open Access Journals (Sweden)

    Denis A. Brosnan

    2014-01-01

    Full Text Available This study characterized mortars from a masonry fortification in Charleston, South Carolina (USA, harbor where construction was during the period 1839–1860. This location for analysis was interesting because of the sea water impingement on the structure. The study was included as part of an overall structural assessment with restoration as an objective. The mortars were found to be cement, lime, and sand mixtures in proportions similar to ones expected from the historic literature, that is, one part binder to two parts of sand. The binder was found to be American natural cement, a substance analogous to the European Roman cement. The results suggest that the thermal history of the cement during manufacturing affected setting rate explaining why the cements were considered as variable during the mid-to-late 1800s. Fine pores were found in mortars exposed to sea water resulting from corrosion. Contemporary natural cement was shown to release calcium in aqueous solution. While this release of calcium is necessary for setting in natural and Portland cements, excessive calcium solution, as exacerbated by sea water contact and repointing with Portland cement mortars, was shown to result in brick scaling or decay through cryptoflorescence.

  8. The long-term durability of low alkali cements. Evidence from new natural analog sites in Europe and North Africa

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, W. Russell [Bedrock Geosciences, Auenstein (Switzerland); Laine, Heini M. [Saanio and Riekkola Oy, Helsinki (Finland); Khoury, Hani [Jordan Univ., Amman (Jordan). Dept. of Geology

    2015-07-01

    The long-term durability of low alkali cements is of interest where they are under consideration as repository tunnel and exploration borehole seals and plugs. It is essential to have an appropriate understanding of their longevity to inform decisions on their potential use in a repository environment. Archaelogical analogues of low alkali cement have been studied for some time. Thomassin and Rassineux (1992), for example, reviewed some of the literature on Gallo-Roman cement-based materials and noted that one of the most impressive examples is the 1700 year old Roman mortar used in Hadrian's Wall (UK) which still contains substantial amounts of CSH (calcium silicate hydrate) compounds. These mortars were studied specifically with the behaviour of an ILW repository in mind (Jull and Lees 1990). However, plugs and seals will generally be required to be durable for longer than the few thousand years which can be accessed via archaeological analogues, so it is essential to turn to natural systems for evidence of longer term durability. To date, there have been no reported studies on natural low alkali cements. In principle, however, such cements should exist and the Bituminous Marl Formation, which hosts the natural OPC cements in Jordan (Pitty and Alexander, 2011), is a likely source. This Formation constitutes a widespread terrain which stretches from Syria in the north, through Israel and Jordan to Saudi Arabia in the south. The natural cement was formed by the combustion of organic rich limestones, a process which continues today. In Syria and northern Jordan, for example, the Formation is punctured by Late Oligocene to Quaternary volcanics so sites which include pozzolanic ash mixed with the Bituminous Marl exist and, on combustion, should produce natural low alkali cements. A site in northern Jordan is currently under investigation for evidence of long-term fresh groundwater/low alkali cement interaction and the preliminary results of the study will be

  9. Optimization of Mix Proportion of High Performance Mortar for Structural Applications

    Directory of Open Access Journals (Sweden)

    Cheah C. Ban

    2010-01-01

    Full Text Available Problem statement: Mortar mix is a major construction material in fabrication of ferrocement structural elements. However, there have been scarce amount of technical data available on suitable mix proportion to achieve structural grade mortar with specific strength requirement and adequate level of workability for proper placement into construction formwork. Moreover, current practice in ferrocement construction work which uses mortar mix with cement: sand ratio ranging between 1:1.5 to 1:2 incurs high requirement of cement yet producing mix with suboptimum level of compressive strength. Approach: An experimental investigation was carried out to evaluate workability and compressive strength properties of structural grade mortar mixes with various cement: sand ratios ranging from 1:2.0-1:2.75 and varying water/binder ratio between 0.35 and 0.50. Throughout the laboratory investigation, a total of 28 batches of mortar mixes with various mix proportion were designed, cast and tested in accordance to relevant standards of practice prescribed by British Standard Institute (BSI and American Society of Testing Material (ASTM. Results: At the end of the laboratory investigation program, high performance mortar mix with compressive strength exceeding 55 MPa and slump level within 50-90 mm which is suitable for heavy duty ferrocement construction work was successfully developed. Moreover, data on mix proportion for several other grades of mortar mixes ranging from grade 35 to grade 55 were also derived. Conclusion: It was found that optimum cement: Sand ratio of structural mortar is 1:2.25. With the use of this cement: Sand ratio in the production of structural grade mortar mix in fabrication of ferrocement structural elements, consumption of cement binder will be economized hence resulting in potential savings in term of material and production cost of mortar mix in the construction industry. Besides, it was also observed that strengths

  10. STUDY OF EXPANSIVE REACTIONS IN MORTAR MADE OF PORTLAND CEMENT WITH RICE HUSK ASH (RHA = ESTUDO DE REAÇÕES EXPANSIVAS EM ARGAMASSAS DE CIMENTO PORTLAND COM CINZA DE CASCA DE ARROZ (CCA

    Directory of Open Access Journals (Sweden)

    Jorge Luis Akasaki

    2007-01-01

    Full Text Available Rice husk is an agroindustrial residue which, when adequately burned and ground, may become an important pozzolan to be added in mortars. One factor contributing to the feasibility of its use is that of the 10 million tons of rice produced annually in this country, two million tons of husk remain, which can produce about 400 thousand tons of ash - enough to supply the market for mortars, concrete andothers. This large amount of material has become an environmental problem because it is being discarded inappropriately. Seeking a viable use of rice husk ash in the civil construction, the present research studies the variation in mortar behavior with different levels of RHA (Rice Husk Ash. Prismatic specimens were used, measuring 25x25x285mm, moulded with 0% (reference, 5%, 10% and 25% RHA. The influence of the RHA’s was verified through the following tests: efficiency of pozzolanic materials in avoiding expansion and alkali-aggregate reaction. The result obtained in the expansion reduction test (NBR 12651 showed that RHA reduces considerably the expansion of mortars due to reaction with the alkalis in the cement(94.29%, with the minimum reduction required by the norm for a pozolan being 75%. Although the expansion values in the alkali-aggregate reaction test (ASTM C-1260 remained above the limit allowed to consider the material innocuous, RHA levels of 5% as well as 10% obtained better results (expanded less then the referenceline. = A casca de arroz é um resíduo agroindustrial que adequadamente queimada e moída, pode se tornar uma importante pozolana a ser adicionada em argamassas. Um fator que viabiliza o seu emprego, é que dos 10 milhões de toneladas de arroz que o país produz por ano, sobram dois milhões de toneladas de casca – que podem rendercerca de 400 mil toneladas de cinza, o suficiente para suprir o mercado de argamassas, concreto e outros. Esta grande quantidade de material produzido passa a se tornar um problema, porque

  11. Recycled sand in lime-based mortars.

    Science.gov (United States)

    Stefanidou, M; Anastasiou, E; Georgiadis Filikas, K

    2014-12-01

    The increasing awareness of the society about safe guarding heritage buildings and at the same time protecting the environment promotes strategies of combining principles of restoration with environmentally friendly materials and techniques. Along these lines, an experimental program was carried out in order to investigate the possibility of producing repair, lime-based mortars used in historic buildings incorporating secondary materials. The alternative material tested was recycled fine aggregates originating from mixed construction and demolition waste. Extensive tests on the raw materials have been performed and mortar mixtures were produced using different binding systems with natural, standard and recycled sand in order to compare their mechanical, physical and microstructure properties. The study reveals the improved behavior of lime mortars, even at early ages, due to the reaction of lime with the Al and Si constituents of the fine recycled sand. The role of the recycled sand was more beneficial in lime mortars rather than the lime-pozzolan or lime-pozzolan-cement mortars as a decrease in their performance was recorded in the latter cases due to the mortars' structure.

  12. Bayesian inference for OPC modeling

    Science.gov (United States)

    Burbine, Andrew; Sturtevant, John; Fryer, David; Smith, Bruce W.

    2016-03-01

    The use of optical proximity correction (OPC) demands increasingly accurate models of the photolithographic process. Model building and inference techniques in the data science community have seen great strides in the past two decades which make better use of available information. This paper aims to demonstrate the predictive power of Bayesian inference as a method for parameter selection in lithographic models by quantifying the uncertainty associated with model inputs and wafer data. Specifically, the method combines the model builder's prior information about each modelling assumption with the maximization of each observation's likelihood as a Student's t-distributed random variable. Through the use of a Markov chain Monte Carlo (MCMC) algorithm, a model's parameter space is explored to find the most credible parameter values. During parameter exploration, the parameters' posterior distributions are generated by applying Bayes' rule, using a likelihood function and the a priori knowledge supplied. The MCMC algorithm used, an affine invariant ensemble sampler (AIES), is implemented by initializing many walkers which semiindependently explore the space. The convergence of these walkers to global maxima of the likelihood volume determine the parameter values' highest density intervals (HDI) to reveal champion models. We show that this method of parameter selection provides insights into the data that traditional methods do not and outline continued experiments to vet the method.

  13. 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.

  14. Characterization of the leaching behaviour of concrete mortars and of cement-stabilized wastes with different waste loading for long term environmental assessment.

    Science.gov (United States)

    van der Sloot, H A

    2002-01-01

    The leaching behaviour of cement-based products-both construction products and cement-stabilized wastes--have been shown to be similar after assessing the leaching characteristics by means of a pH dependence leaching test. This procedure is particularly suited to identifying the chemical speciation of materials. Geochemical modelling has shown a number of solubility controlling phases in this largely inorganic matrix, that can very well explain the observed leaching patterns as a function of pH. Understanding these relationships allows the prediction of leaching behaviour under other exposure conditions and to improve the ultimate quality of products, if so desired. The role of ettringite-type phases for the binding of oxyanions in the pH range above pH 12 has been identified before and confirmed in this work. The order of incorporation follows from the ratio between the maximum leachability at mildly alkaline pH and at high pH. Increased levels of sulfate negatively influence the binding of oxyanions in cement-stabilized waste through site competition.

  15. Mortar and concrete based on calcium sulphate binders

    OpenAIRE

    Bakker, J.J.F.; Brouwers, H. J. H.

    2006-01-01

    In this study both hemi-hydrate and anhydrite are tested as calcium sulphate binders for structural mortar and concrete. The advantage of using calcium sulphates instead of cement as a binder is the fact that the production of calcium sulphate is more environmental friendly than that of cement. For the calcinations of Portland cement, temperatures up to 1480 oC are needed, while the calcination of for instance hemihydrate requires a temperature of 170 oC

  16. Influence Of Volcanic Scoria On Mechanical Strength, Chemical Resistance And Drying Shrinkage Of Mortars

    Directory of Open Access Journals (Sweden)

    Al-Swaidani A.

    2014-09-01

    Full Text Available In the study, three types of cement have been prepared; one CEM I type (the control sample and two blended cements: CEM II/A-P and CEM II/B-P (EN 197-1, each of them with three replacement levels of volcanic scoria: (10 %, 15 %, 20 % wt. and (25 %, 30 %, 35 % wt., respectively. Strength development of mortars has been investigated at 2, 7, 28 and 90 days curing. Evaluation of chemical resistance of mortars containing scoria-based cements has been investigated through exposure to 5 % sulphate and 5 % sulphuric acid solutions in accordance with ASTM C1012 & ASTM 267, respectively. Drying shrinkage has been evaluated in accordance with ASTM C596. Test results showed that at early ages, the mortars containing CEM II/B-P binders had strengths much lower than that of the control mortar. However, at 90 days curing, the strengths were comparable to the control mortar. In addition, the increase of scoria significantly improved the sulphate resistance of mortars. Further, an increase in scoria addition improved the sulphuric acid resistance of mortar, especially at the early days of exposure. The results of drying shrinkage revealed that the CEM II/B-P mortar bars exhibited a greater contraction when compared to the control mortar, especially at early ages. However, drying shrinkage of mortars was not influenced much at longer times.

  17. Effect of Fly Ash on Microstructure Property of Cement Mortar%粉煤灰对水泥砂浆微结构性能的影响

    Institute of Scientific and Technical Information of China (English)

    张乃明

    2014-01-01

    矿物掺合料如粉煤灰、矿渣等,能显著改善结构混凝土的耐久性,而得到普遍应用。从微观角度出发,采用压汞法(MIP)和X-CT断层扫描技术分析粉煤灰分别为10%、30%和50%对水泥基材料微结构的影响,进一步从氯离子传输角度分析掺合料对微结构改变的本质。压汞法的结果表明,粉煤灰掺量从10%到50%,水泥基材料的毛细孔和凝胶孔的体积率分别减少和增加,但总孔隙率在50%时出现增加;X-CT三维重构的结果显示,水泥基材料的微缺陷随着掺合料的增加而减少;氯离子传输的实验显示,含50%掺合料的试样,具有较大的传输系数,表明不适量的掺合料会降低水泥基材料的抗渗透性能。%Mineral admixture like fly ash and slag is applied widely because it can greatly improve the durability of the structure concrete. The Mercury Intrusion Pore method (MIP) and X-CT were employed to study the effect of binding materials with 10%, 30%and 50%fly ash on microstructure property of cement based materials, which further analyzes the affect of admixture to the microstructure property from the angle of chloride ion diffusion. Test result of MIP shows that volume fraction of capillary pore and gel pore in cement based materials decreased and increased with fly ash content from 10%~50%, total pore volume fraction of cement based materials increased with 50% of admixture. 3D reconfiguration result of X-CT indicates that micro-defect volume fraction of cement based materials decreased with increasing fly ash content. The Chloride ion penetration resistance of cement based materials decreased at 50 % content of admixture.

  18. The Influence of Mineral Admixtures on Bending Strength of Mortar on the Premise of Equal Compressive Strength

    Institute of Scientific and Technical Information of China (English)

    WANG Qiang; YAN Peiyu; FENG Jianwen

    2012-01-01

    The influence of mineral admixtures on bending strength of mortar on the premise of equal compressive strength was investigated.Three mineral admixtures (fly ash,ground granulated blast-furnace slag and steel slag) were used.The adding amount of mineral admixture in this study ranges from 22.5% to 60%,and the water-to-binder ratio ranges from 0.34 to 0.50.With equal compressive strength,different mortars can be arranged in such a descending order with their bending strength:cement-fly ash mortar,cement mortar,cement-GGBS mortar,and cement-steel slag mortar.With the same compressive strength,the higher the steel slag content and water-to-binder ratio,the lower the bending strength of mortars.However,the effect of mineral mixture content and water-to-binder ratio on the bending strength of cement-fly ash mortar and cement-GGBS mortar is far inconspicuous.

  19. Porosity estimation of aged mortar using a micromechanical model.

    Science.gov (United States)

    Hernández, M G; Anaya, J J; Sanchez, T; Segura, I

    2006-12-22

    Degradation of concrete structures located in high humidity atmospheres or under flowing water is a very important problem. In this study, a method for ultrasonic non-destructive characterization in aged mortar is presented. The proposed method makes a prediction of the behaviour of aged mortar accomplished with a three phase micromechanical model using ultrasonic measurements. Aging mortar was accelerated by immersing the probes in ammonium nitrate solution. Both destructive and non-destructive characterization of mortar was performed. Destructive tests of porosity were performed using a vacuum saturation method and non-destructive characterization was carried out using ultrasonic velocities. Aging experiments show that mortar degradation not only involves a porosity increase, but also microstructural changes in the cement matrix. Experimental results show that the estimated porosity using the proposed non-destructive methodology had a comparable performance to classical destructive techniques.

  20. Optimization of Blended Mortars Using Steel Slag Sand

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new kind of mortar made of ground granulated blast-furnace slag (GGBFS), gypsum,clinker and steel slag sand (<4.75 mm) was developed. The ratio of steel slag sand to GGBFS was 1:1 and the amount of gypsum was 4% by weight while the dosage of clinker ranged from 0% to 24%. The optimization formulation of such mortar was studied. The content of steel slag sand should be less than 50% according to the volume stability of blended mortar, and the dosage of clinker is about 10% based on the strength development.Besides strength, the hydration heat, pore structure and micro pattern of blended mortar were also determined.The experimental results show the application of steel slag sand may reduce the dosage of cement clinker and increase the content of industrial waste product such as GGBFS, and the clinker is also a better admixture for blended mortar using steel slag sand.

  1. Preliminary investigation of the effect of air-pollution-control residue from waste incineration on the properties of cement paste and mortar

    DEFF Research Database (Denmark)

    Geiker, Mette Rica; Kjeldsen, Ane Mette; Galluci, Emmanuel;

    2006-01-01

    For preliminary assessment of the engineering properties of concrete with air-pollution-control residue from waste incineration (APC) the possible reactivity of APC and the effect of APC on cement hydration were investigated by isothermal calorimetry, chemical shrinkage (pychnometry), thermal...... analysis (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Furthermore, compressive strength development was measured and impregnated plane sections were prepared. The APC was from a Danish wet process plant. Although the APC contained high amounts of chloride (approx. 10%) and heavy...

  2. Neutron radiography of heated high-performance mortar

    OpenAIRE

    Weber B; Wyrzykowski M.; Griffa M.; Carl S.; Lehmann E.; Lura P.

    2013-01-01

    Neutron radiography was applied to investigate the water distribution in mortar samples heated from one side to 600 °C. In mortar, aggregates and anhydrous cement are almost transparent to neutrons, while hydration products and water-filled capillary pores bear the largest attenuation. The evolution of the moisture profile shows a sharp dehydration front and accumulation of water due to condensation of water vapor behind this front.

  3. Neutron radiography of heated high-performance mortar

    Directory of Open Access Journals (Sweden)

    Weber B.

    2013-09-01

    Full Text Available Neutron radiography was applied to investigate the water distribution in mortar samples heated from one side to 600 °C. In mortar, aggregates and anhydrous cement are almost transparent to neutrons, while hydration products and water-filled capillary pores bear the largest attenuation. The evolution of the moisture profile shows a sharp dehydration front and accumulation of water due to condensation of water vapor behind this front.

  4. Laboratory Investigation on the Strength Gaining of Brick Aggregate Concrete Using Ordinary Portland Cement and Portland Composite Cement

    Directory of Open Access Journals (Sweden)

    Hoque M H, Numen E H, Islam N., Mohammed

    2014-05-01

    Full Text Available This study focused on the laboratory investigation of strength variation of brick aggregate concrete made with ordinary Portland cement (OPC and Portland composite cement (PCC.The investigation was conducted by testing concrete cylinder specimens at different ages of concrete with concrete mix ratios: 1:1.5:3 and 1:2:4 by volume and with water cement ratios=0.45 and 0.60. The test result reveals that at the early age, concrete composed with OPC attained larger compressive strength than the concrete made of PCC. However, in the later age concrete made with PCC achieved higher strength than OPC.

  5. Strength and durability of concrete: Effects of cement paste-aggregate interfaces. Part 2: Significance of transition zones on physical and mechanical properties of portland cement mortar; Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T.F.F.; Cohen, M.D.; Chen, W.F.; Zhang, Y.

    1998-08-01

    The research was based on a two-part basic research investigation studying the effects of cement paste-aggregate interfaces (or interfacial transition zones-ITZ) on strength and durability of concrete. Part 1 dealt with the theoretical study and Part 2 dealt with the experimental.

  6. UAF: a generic OPC unified architecture framework

    Science.gov (United States)

    Pessemier, Wim; Deconinck, Geert; Raskin, Gert; Saey, Philippe; Van Winckel, Hans

    2012-09-01

    As an emerging Service Oriented Architecture (SOA) specically designed for industrial automation and process control, the OPC Unied Architecture specication should be regarded as an attractive candidate for controlling scientic instrumentation. Even though an industry-backed standard such as OPC UA can oer substantial added value to these projects, its inherent complexity poses an important obstacle for adopting the technology. Building OPC UA applications requires considerable eort, even when taking advantage of a COTS Software Development Kit (SDK). The OPC Unied Architecture Framework (UAF) attempts to reduce this burden by introducing an abstraction layer between the SDK and the application code in order to achieve a better separation of the technical and the functional concerns. True to its industrial origin, the primary requirement of the framework is to maintain interoperability by staying close to the standard specications, and by expecting the minimum compliance from other OPC UA servers and clients. UAF can therefore be regarded as a software framework to quickly and comfortably develop and deploy OPC UA-based applications, while remaining compatible to third party OPC UA-compliant toolkits, servers (such as PLCs) and clients (such as SCADA software). In the rst phase, as covered by this paper, only the client-side of UAF has been tackled in order to transparently handle discovery, session management, subscriptions, monitored items etc. We describe the design principles and internal architecture of our open-source software project, the rst results of the framework running at the Mercator Telescope, and we give a preview of the planned server-side implementation.

  7. Comparative investigation of mortars from Roman Colosseum and cistern

    Energy Technology Data Exchange (ETDEWEB)

    Silva, D.A. [Department of Civil and Environmental Engineering, 725 Davis Hall 94720-1710, University of California at Berkeley, Berkeley, CA (United States)]. E-mail: denise@ecv.ufsc.br; Wenk, H.R. [Department of Earth and Planetary Science, 497 McCone 94720-4767, University of California at Berkeley, Berkeley, CA (United States); Monteiro, P.J.M. [Department of Civil and Environmental Engineering, 725 Davis Hall 94720-1710, University of California at Berkeley, Berkeley, CA (United States)

    2005-11-01

    Mortar from the Roman Colosseum and a Roman cistern from Albano Laziale were characterized with optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and thermal analysis (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). The different techniques provided consistent results that the mortar of the Colosseum is mainly calcareous lime, while the mortar of the cistern is pozzolanic siliceous material. The study highlights the capabilities of the different methods for the analysis of cement. For routine analysis XRD is adequate but for characterization of poorly crystalline phases FT-IR and TGA have definite advantages.

  8. An electrochemical and microstructural characterization of steel-mortar admixed with corrosion inhibitors

    Institute of Scientific and Technical Information of China (English)

    Tuan; Anh; Nguyen; Recep; AVCI

    2009-01-01

    The present research brings new insights on the role of admixed corrosion inhibitors in the processes of cement hydration and rebar corrosion. The admixing of NaCl and the corrosion inhibitors in fresh mortar was found to alter the morphology and microstructure of the hardened mortar at the steel-mortar interfacial region. The admixing of the inhibitors increased the risk of carbonation of cement hydrates at the steel-mortar interfacial region, but partially displaced chloride ions. Chloride and the admixed inhibitors facilitated the formation of different cement hydrates and affected chloride binding at the steel-mortar interfacial region. The admixing of all three inhibitors was found to increase the polarization resistance of steel, indicating reduced corrosion rate of the steel over 48-day exposures to salt ponding.

  9. Intelligent model-based OPC

    Science.gov (United States)

    Huang, W. C.; Lai, C. M.; Luo, B.; Tsai, C. K.; Chih, M. H.; Lai, C. W.; Kuo, C. C.; Liu, R. G.; Lin, H. T.

    2006-03-01

    Optical proximity correction is the technique of pre-distorting mask layouts so that the printed patterns are as close to the desired shapes as possible. For model-based optical proximity correction, a lithographic model to predict the edge position (contour) of patterns on the wafer after lithographic processing is needed. Generally, segmentation of edges is performed prior to the correction. Pattern edges are dissected into several small segments with corresponding target points. During the correction, the edges are moved back and forth from the initial drawn position, assisted by the lithographic model, to finally settle on the proper positions. When the correction converges, the intensity predicted by the model in every target points hits the model-specific threshold value. Several iterations are required to achieve the convergence and the computation time increases with the increase of the required iterations. An artificial neural network is an information-processing paradigm inspired by biological nervous systems, such as how the brain processes information. It is composed of a large number of highly interconnected processing elements (neurons) working in unison to solve specific problems. A neural network can be a powerful data-modeling tool that is able to capture and represent complex input/output relationships. The network can accurately predict the behavior of a system via the learning procedure. A radial basis function network, a variant of artificial neural network, is an efficient function approximator. In this paper, a radial basis function network was used to build a mapping from the segment characteristics to the edge shift from the drawn position. This network can provide a good initial guess for each segment that OPC has carried out. The good initial guess reduces the required iterations. Consequently, cycle time can be shortened effectively. The optimization of the radial basis function network for this system was practiced by genetic algorithm

  10. 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.

  11. Effect of water-repellent admixtures on the behaviour of aerial lime-based mortars

    OpenAIRE

    Izaguirre, A.; Lanas, J.; Alvarez, J I

    2009-01-01

    Two different anionic surfactants, sodium oleate and calcium stearate, commercialized as water repellents for cement-based mortars, were added to lime-based mortars in order to check whether they were improved by these admixtures. Different properties of lime-based mortars were evaluated: fresh state behaviour through water retention, air content and setting time, hardened state properties such as density, water absorption through capillarity, water vapour permeability, long-term compressive ...

  12. Integrating OPC Data into GSN Infrastructures

    CERN Document Server

    Passalacqua, Olivier; Huget, Marc-Philippe; Moreaux, Patrice

    2008-01-01

    This paper presents the design and the implementation of an interface software component between OLE for Process Control (OPC) formatted data and the Global Sensor Network (GSN) framework for management of data from sensors. This interface, named wrapper in the GSN context, communicates in Data Access mode with an OPC server and converts the received data to the internal GSN format, according to several temporal modes. This work is realized in the context of a Ph.D. Thesis about the control of distributed information fusion systems. The developed component allows the injection of OPC data, like measurements or industrial processes states information, into a distributed information fusion system deployed in a GSN framework. The component behaves as a client of the OPC server. Developed in Java and based on the Opensaca Utgard, it can be deployed on any computation node supporting a Java virtual machine. The experiments show the component conformity according to the Data Access 2.05a specification of the OPC st...

  13. Multivariate optimization and simultaneous determination of hydride and non-hydride-forming elements in samples of a wide pH range using dual-mode sample introduction with plasma techniques: application on leachates from cement mortar material.

    Science.gov (United States)

    Mulugeta, Mesay; Wibetoe, Grethe; Engelsen, Christian J; Asfaw, Alemayehu

    2009-02-01

    Analytical methods have been developed for the simultaneous determination of hydride-forming (As, Sb) and non-hydride-forming (Cr, Mo, V) elements in aqueous samples of a wide pH range (pH 3-13). The methods used dual-mode (DM) sample introduction with ICP-AES and ICP-MS instruments. The effect of selected experimental variables, i.e., sample pH and concentrations of HNO(3), thiourea, and NaBH(4), were studied in a multivariate way using face-centered central composite design (FC-CCD). Compromised optimum values of the experimental parameters were identified using a response optimizer. The statistically found optimum values were verified experimentally. The methods provided improved sensitivities for the hydride-forming elements compared with the respective conventional nebulization (Neb) systems by factors of 67 (As) and 64 (Sb) for ICP-AES and 36 (As) and 54 (Sb) for ICP-MS. Slight sensitivity improvements were also observed for the non-hydride-forming elements. The limits of detection (LOD) of As and Sb were lowered, respectively, to 0.8 and 0.9 microg L(-1) with the DM-ICP-AES system and to 0.01 and 0.02 microg L(-1) with the DM-ICP-MS system. The short-term stabilities of both methods were between 2.1 and 5.4%. The methods were applied for the analysis of leachates of a cement mortar material prepared in the pH range 3-13. The elemental concentration of the leachates determined by the two DM methods were statistically compared with the values obtained from Neb-ICP-MS analysis; the values showed good agreement at the 95% confidence level. Quantitative spike recoveries were obtained for the analytes from most of the leachates using both DM methods.

  14. Valorization of Drinking Water Treatment Sludges as Raw Materials to Produce Concrete and Mortar

    Directory of Open Access Journals (Sweden)

    R. M.R. Zamora

    2008-01-01

    Full Text Available The purpose of this work was to assess the technical feasibility to valorize sludges, generated and stored at the Los Berros drinking water facility (PPLB, as raw material to produce building products (mortar and concrete for the construction industry. The experimental study was divided into three stages: 1 sampling and characterization of PPLB sludges to determine their potential as raw material (sand substitute and supplementary cementing materials to produce mortar and concrete; 2 production and characterization of specimens, using sludge in different weight ratios of mixtures with cement, lime, commercial mortar and plaster to prepare mortars and concretes and 3 comparison of compressive strength and drying contraction values between each specimen and the Mexican criteria to build mortars and concretes. The characterization results of the PPLB sludges showed that these residues could be used as a sand substitute in mortar and concrete formulations, since they were mainly comprised of this material (46.83%. The specimens prepared with a the binary formulations, sludge-cement and sludge-mortar (90-10% and b the ternary formulation, sludge-lime-cement (90-5-5%, gave the best results (ranging from 130 to 150 kg cm-2 of the compressive strength test. The compressive strength values of these formulations were higher than those of equivalent mortar (types I, II and III and cement mixtures (125 kg cm-2 prepared according to the Mexican complementary technical criteria to design and build masonry. These cementing properties exhibited by the PPLB sludges might be associated to their high content of aluminum and silicon oxides, 31.98 and 33.23%, respectively. Thus, calcium silicate (the main carrier strength in hardened cement can be produced from lime hydration of cement with the active silica present in the sludge. Considering all these results, the PPLB sludges present a high feasibility for being valorized as raw materials (supplementary cementing

  15. Properties of Foamed Mortar Prepared with Granulated Blast-Furnace Slag

    Directory of Open Access Journals (Sweden)

    Xiao Zhao

    2015-01-01

    Full Text Available Foamed mortar with a density of 1300 kg/m3 was prepared. In the initial laboratory trials, water-to-cement (w/c ratios ranging from 0.54 to 0.64 were tested to determine the optimal value for foamed mortar corresponding to the highest compressive strength without compromising its fresh state properties. With the obtained optimal w/c ratio of 0.56, two types of foamed mortar were prepared, namely cement-foamed mortar (CFM and slag-foamed mortar (SFM, 50% cement was replaced by slag weight. Four different curing conditions were adopted for both types of foamed mortar to assess their compressive strength, ultrasonic pulse velocity (UPV and thermal insulation performance. The test results indicated that utilizing 50% of slag as cement replacement in the production of foamed mortar improved the compressive strength, UPV and thermal insulation properties. Additionally, the initial water curing of seven days gained higher compressive strength and increased UPV values as compared to the air cured and natural weather curing samples. However, this positive effect was more pronounced in the case of compressive strength than in the UPV and thermal conductivity of foamed mortar.

  16. Reuse of ground waste glass as aggregate for mortars.

    Science.gov (United States)

    Corinaldesi, V; Gnappi, G; Moriconi, G; Montenero, A

    2005-01-01

    This work was aimed at studying the possibility of reusing waste glass from crushed containers and building demolition as aggregate for preparing mortars and concrete. At present, this kind of reuse is still not common due to the risk of alkali-silica reaction between the alkalis of cement and silica of the waste glass. This expansive reaction can cause great problems of cracking and, consequently, it can be extremely deleterious for the durability of mortar and concrete. However, data reported in the literature show that if the waste glass is finely ground, under 75mum, this effect does not occur and mortar durability is guaranteed. Therefore, in this work the possible reactivity of waste glass with the cement paste in mortars was verified, by varying the particle size of the finely ground waste glass. No reaction has been detected with particle size up to 100mum thus indicating the feasibility of the waste glass reuse as fine aggregate in mortars and concrete. In addition, waste glass seems to positively contribute to the mortar micro-structural properties resulting in an evident improvement of its mechanical performance.

  17. Interfacial (Fiber-matrix) Properties of High-strength Mortar (150 MPa) from Fiber Pullout

    DEFF Research Database (Denmark)

    Shannag, M.J.; Brincker, Rune; Hansen, Will

    1996-01-01

     The steel fiber-matrix properties of high-strength mortar (150 MPa), such as DSP (densified small particle), are obtained and compared to an ordinary strength mortar (40 MPa) using a specially designed fiber pullout apparatus. A new method for estimating the debonding energy of the interfacial......-strength DSP mortar has significantly improved interfacial properties compared to ordinary strength mortar. These results are important in the understanding of the role of steel fibers in improving the tensile properties of high-strength, brittle, cement-matrix composites....

  18. Enforcement of Mask Rule Compliance in Model-Based OPC'ed Layouts during Data Preparation

    Science.gov (United States)

    Meyer, Dirk H.; Vuletic, Radovan; Seidl, Alexander

    2002-12-01

    Currently available commercial model-based OPC tools do not always generate layouts which are mask rule compliant. Additional processing is required to remove mask rule violations, which are often too numerous for manual patching. Although physical verification tools can be used to remove simple mask rule violations, the results are often unsatisfactory for more complicated geometrical configurations. The subject of this paper is the development and application of a geometrical processing engine that automatically enforces mask rule compliance of the OPC'ed layout. It is designed as an add-on to a physical verification tool. The engine constructs patches, which remove mask rule violations such as notches or width violations. By employing a Mixed Integer Programming (MIP) optimization method, the edges of each patch are placed in a way that avoids secondary violations while modifying the OPC'ed layout as little as possible. A sequence of enforcement steps is applied to the layout to remove all types of mask rule violations. This approach of locally confined minimal layout modifications retains OPC corrections to a maximum amount. This method has been used successfully in production on a variety of DRAM designs for the non-array regions.

  19. Drying shrinkage of mortars with limestone filler and blast-furnace slag

    OpenAIRE

    Carrasco, M. F.; Bonavetti, V. L.; Irassar, E. F.

    2003-01-01

    During the 1990's the use of cements made with port land clinker and two mineral admixtures, called ternary or blended cements, has grown considerably. Nowadays, cements containing several combinations of fly ash and silica fume, blast-furnace slag and silica fume or blast-furnace slag and limestone filler are commonly used. There are numerous works on the influence of blended cements on the fresh state and mechanical properties of mortar and concrete, but the their deformations due to drying...

  20. INFLUENCE OF ENVIRONMENTAL CHARACTERISTICS ON SULFATE ATTACK TYPES OF CEMENT MORTARS%特性环境对水泥砂浆硫酸盐侵蚀类型的影响

    Institute of Scientific and Technical Information of China (English)

    马保国; 罗忠涛; 李相国; 高小建; 张美香

    2007-01-01

    研究了硫酸盐种类(Na2SO4,MgSO4)及温度(5 ℃,20 ℃)等影响因素对水泥砂浆硫酸盐侵蚀类型的影响,以明确碳硫硅酸钙型硫酸盐侵蚀的特性环境条件.试验结果表明:掺加石灰石粉的水泥砂浆试件置于5% MgSO4溶液、5 ℃及20 ℃温度环境下浸泡450 d后,均能生成碳硫硅酸钙.而一般水泥砂浆试件置于5% Na2SO4溶液、5 ℃及20 ℃温度环境浸泡侵蚀后,未生成碳硫硅酸钙.证明水泥混凝土在>15 ℃的硫酸盐侵蚀环境下亦可生成碳硫硅酸钙,而Mg2+的存在对碳硫硅酸钙的形成过程具有加速催化作用.%The influence of environmental factors with different sulfate types (Na2SO4, MgSO4) and temperatures (5, 20 ℃) on various kinds of sulfate attack of cement mortars was studied, and the special environmental factors for the formation of thaumasite were confirmed. The experimental results show that after immersion for 450 d, the samples including limestone exposed to 5% MgSO4 solution at 5 ℃ and 20 ℃ both could produce thaumasite. However, thaumasite could not be found in the samples without limestone exposed to 5% Na2SO4 solution at 5 ℃ and 20 ℃. This proves that concrete can produce thaumasite in a sulfate environment over 15 ℃, and the existence of Mg2+ can accelerate the formation of thaumasite.

  1. The colour potentials of SSA-containing mortar

    DEFF Research Database (Denmark)

    Kappel, Annemette; Ottosen, Lisbeth M.; Kirkelund, Gunvor Marie;

    2015-01-01

    is with a few exceptions landfilled and thus, wasted.The purpose of the experiments was to examine the influence of SSA and how it affected the colour of mortar samples. SSA was ground in 6 different intervals and added to mortar mixes by replacing 20% of the cement. An additional focus was to examine......This paper reports an experimental study of aesthetical qualities of mortar containing sewage sludgeash (SSA). SSA is the residue produced at water treatment plants where incineration of the sludge is applied in order to decrease volume and to prevent pathogens from spreading. Today SSA...... the possibilities to accentuate the colours of the hardened mortar by using paper cuttings in the production of the samples. The result of the experiments showed that a colour scale can be developed from ground SSA, and that paper may have the potential of providing divers textural qualities when it is used...

  2. A study of the application of residue from burned biomass in mortars

    Directory of Open Access Journals (Sweden)

    Enori Gemelli

    2004-12-01

    Full Text Available The goal of this work was to study the viability of burnt biomass residue from a pulp and paper plant applied as a raw material for mortar used in the construction industry. The waste - bottom ash - was incorporated into the mortar as a mineral addition to the Portland cement. The effect of the waste's grain size on the properties of mortars containing 10% in volume of waste was investigated, as well as the effect of the concentration of waste with grain size under 0.15 mm. The samples were evaluated after 28 days of aging by uniaxial compression, leaching test and scanning electron microscopy. These characterization techniques indicated that the properties of the mortars depend on the concentration, granulation and size distribution of the waste in the mortar's structure. Furthermore, some chemical elements may be present in stabilized and/or encapsulated form in the cement matrix.

  3. Effect of Modified Polymer on Crack Resistance of Mortar

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    At present, the basic technical principle in China is to adopt polymers to modifying the properties of mortar so as to improve the crack-resistance of construction structures and to strengthen their water-resisting and climate-resisting properties as well. However, how polymer acts on anti-crack mortar is short of systematic research. Theoretical exposition of polymer mortar is basically explained by Ohama Model, which is cement slaking and polymer coating are carried on together and mutually-cross web structure interweaved with liquid and polymer coating. But anti-crack mortar has its own special characteristics because of fewer polymers mixed in it and its high viscosity. So this paper is to showing how different polymers affect its crack-resistance cannot be reflected from this theory. Vinyl-acetate ethylene (VAC/E) has been selected as representation of polymerization, whose property is modified by compounding it from some inorganic components, such as talc, CaCO3 and so on. And then the mechanics property and shrinkage of anti-crack polymer mortar is tested when different amount of polymers is added as admixture of mortar. The result indicates that, the working performance and mechanics property of the polymer mortar are worse mixed VAC/E only. It basically meets the demands for mechanics strength and working performance when mixed both VAC/E and CaCO3. While it achieves much better mechanical property and working performance than the two former when mixed VAC/E,talc and CaCO3; the result of corresponding scanning electron microscopy (SEM) of sample indicates that the internal result of the polymer mortar, compared with classical Ohama Model, has a particularity that its structure is formed by polymer coating instead of filling up the intervals among cement grains.

  4. Use of Artificial Neural Network for the Simulation of Radon Emission Concentration of Granulated Blast Furnace Slag Mortar.

    Science.gov (United States)

    Jang, Hong-Seok; Xing, Shuli; Lee, Malrey; Lee, Young-Keun; So, Seung-Young

    2016-05-01

    In this study, an artificial neural networks study was carried out to predict the quantity of radon of Granulated Blast Furnace Slag (GBFS) cement mortar. A data set of a laboratory work, in which a total of 3 mortars were produced, was utilized in the Artificial Neural Networks (ANNs) study. The mortar mixture parameters were three different GBFS ratios (0%, 20%, 40%). Measurement radon of moist cured specimens was measured at 3, 10, 30, 100, 365 days by sensing technology for continuous monitoring of indoor air quality (IAQ). ANN model is constructed, trained and tested using these data. The data used in the ANN model are arranged in a format of two input parameters that cover the cement, GBFS and age of samples and, an output parameter which is concentrations of radon emission of mortar. The results showed that ANN can be an alternative approach for the predicting the radon concentration of GBFS mortar using mortar ingredients as input parameters.

  5. Use of Artificial Neural Network for the Simulation of Radon Emission Concentration of Granulated Blast Furnace Slag Mortar.

    Science.gov (United States)

    Jang, Hong-Seok; Xing, Shuli; Lee, Malrey; Lee, Young-Keun; So, Seung-Young

    2016-05-01

    In this study, an artificial neural networks study was carried out to predict the quantity of radon of Granulated Blast Furnace Slag (GBFS) cement mortar. A data set of a laboratory work, in which a total of 3 mortars were produced, was utilized in the Artificial Neural Networks (ANNs) study. The mortar mixture parameters were three different GBFS ratios (0%, 20%, 40%). Measurement radon of moist cured specimens was measured at 3, 10, 30, 100, 365 days by sensing technology for continuous monitoring of indoor air quality (IAQ). ANN model is constructed, trained and tested using these data. The data used in the ANN model are arranged in a format of two input parameters that cover the cement, GBFS and age of samples and, an output parameter which is concentrations of radon emission of mortar. The results showed that ANN can be an alternative approach for the predicting the radon concentration of GBFS mortar using mortar ingredients as input parameters. PMID:27483913

  6. Improvement of the efficiency of OPC data handling

    Science.gov (United States)

    Toyama, Nobuhito; Ikemoto, Takayuki; Ishida, Kouji; Miyashita, Hiroyuki

    2001-01-01

    OPC has been acknowledged essential technique to achieve low k1 lithography applying any optical process or even if phase-shift controlling. Since several years ago some aspect of OPC technique has been realized with OPC oriented tools, applied to actual design, and many success stories are reported. However according to semiconductor design scale itself is growing as millions of transistors a year as the rule decreasing, so called aggressive OPC is forcing not only data handling distress but also reticle fabrication difficulty even though the hardware's progressing. In this paper, we introduce the evaluation of the performance and the effect from weak to aggressive OPC that has been proposed. Then we will discuss the improved OPC applying modeling and criteria based on the trade off between OPC data handling efficiency and the effect.

  7. Plastic shrinkage of mortars with shrinkage reducing admixture and lightweight aggregates studied by neutron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wyrzykowski, Mateusz, E-mail: mateusz.wyrzykowski@empa.ch [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland); Lodz University of Technology, Department of Building Physics and Building Materials, Lodz (Poland); Trtik, Pavel [Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, Villigen (Switzerland); Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland); Münch, Beat [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland); Weiss, Jason [Purdue University, School of Civil Engineering, West Lafayette (United States); Vontobel, Peter [Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, Villigen (Switzerland); Lura, Pietro [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Dübendorf (Switzerland); ETH Zurich, Institute for Building Materials (IfB), Zurich (Switzerland)

    2015-07-15

    Water transport in fresh, highly permeable concrete and rapid water evaporation from the concrete surface during the first few hours after placement are the key parameters influencing plastic shrinkage cracking. In this work, neutron tomography was used to determine both the water loss from the concrete surface due to evaporation and the redistribution of fluid that occurs in fresh mortars exposed to external drying. In addition to the reference mortar with a water to cement ratio (w/c) of 0.30, a mortar with the addition of pre-wetted lightweight aggregates (LWA) and a mortar with a shrinkage reducing admixture (SRA) were tested. The addition of SRA reduced the evaporation rate from the mortar at the initial stages of drying and reduced the total water loss. The pre-wetted LWA released a large part of the absorbed water as a consequence of capillary pressure developing in the fresh mortar due to evaporation.

  8. Strength, porosity, and chloride resistance of mortar using the combination of two kinds of pozzolanic materials

    Science.gov (United States)

    Rukzon, Sumrerng; Chindaprasirt, Prinya

    2013-08-01

    This article presents a study on the resistance to chloride penetration, corrosion, porosity, and strength of mortar containing fine fly ash (FA), ground rice husk-bark ash (RB), and ground bagasse ash (BA). Ordinary Portland cement (CT) was blended with a single pozzolan and two pozzolans. Strength, porosity, rapid chloride penetration, immersion, and corrosion tests were performed to characterize the mortar. Test results showed that the use of ternary blends of CT, FA, and RB or BA decreased the porosity of the mortar, as compared with binary blended mortar containing CT and RB or BA. The resistance to chloride penetration of the mortar improved substantially with partial replacement of CT with FA, RB, and BA. The use of ternary blends of CT, FA and RB or BA produced the mortar with good strength and resistance to chloride penetration. The resistance to chloride penetration was higher with an increase in the replacement level due to the reduced calcium hydroxide.

  9. Filler effect of fine particle sand on the compressive strength of mortar

    Science.gov (United States)

    Jaturapitakkul, Chai; Tangpagasit, Jatuphon; Songmue, Sawang; Kiattikomol, Kraiwood

    2011-04-01

    The river sand, which is a non-pozzolanic material, was ground into 3 different particle sizes. Portland cement type I was replaced by the ground river sands at 10wt%-40wt% of binder to cast mortar. Compressive strengths of mortar were investigated and the filler effect of different fine particles of sand on the compressive strength of mortar was evaluated. The results show that the compressive strength of mortar contributed from the filler effect of smaller particles is higher than that of the coarser ones. The difference in compressive strength of mortar tends to be greater as the difference in ground river sand fineness increases. The results also suggest that ASTM C618 specification is not practically suitable for specifying pozzolan in concrete since the strength activity index of mortar containing ground river sand (high crystalline phase) with 33.8wt% of particles retained on a 45-μm sieve can pass the strength requirement.

  10. An electrochemical and microstructural characterization of steel-mortar admixed with corrosion inhibitors

    Institute of Scientific and Technical Information of China (English)

    SHI XianMing; YANG ZhengXian; Tuan Anh Nguyen; SUO ZhiYong; Recep AVCI; SONG ShiZhe

    2009-01-01

    The present research brings new insights on the role of admixed corrosion inhibitors in the processes of cement hydration and rebar corrosion. The admixing of NaCI and the corrosion inhibitors in fresh mortar was found to alter the morphology and microstructure of the hardened mortar at the steel-mor-tar interfacial region. The admixing of the inhibitors increased the risk of carbonation of cement hy-drates at the steel-mortar interracial region, but partially displaced chloride ions. Chloride and the ad-mixed inhibitors facilitated the formation of different cement hydrates and affected chloride binding at the steel-mortar interfacial region. The admixing of all three inhibitors was found to increase the po-larization resistance of steel, indicating reduced corrosion rate of the steel over 48-day exposures to salt ponding.

  11. The effects of nano-materials on the behaviors of sludge mortar specimens.

    Science.gov (United States)

    Luo, H L; Lin, D F; Kuo, W T

    2004-01-01

    In this research, nano-composites are added to sewage sludge ash to create a mixture, which then replaces part of cement. Nano-composites are manufactured from pure quartzose sand. The influences of different amounts of nano-composites and sludge ash on mortar are evaluated. Cement, sludge ash (0%, 10%, and 20%), and nano-composites (0%, 0.5%, 1%, 2%, and 3%), which defined as the percent weight of cement and sludge ash, are mixed together in batches to make mortar specimens. Results show that the flowability of sludge ash mortar reduces with increasing amount of cement replaced and of nano-composites added. The compressive strength of mortar lowers when more amounts of cement are replaced by sludge ash, but increases with more quantity of nano-composites added. Moreover, the study shows that nano-composites can fortify the compressive strength of mortar. With the help of efficiency of compressive strength, nano-composites benefit most to the mortar with replacement of 10% sludge ash, followed by the substitution of 20% and 0%.

  12. Concretes and mortars with waste paper industry: Biomass ash and dregs.

    Science.gov (United States)

    Martínez-Lage, Isabel; Velay-Lizancos, Miriam; Vázquez-Burgo, Pablo; Rivas-Fernández, Marcos; Vázquez-Herrero, Cristina; Ramírez-Rodríguez, Antonio; Martín-Cano, Miguel

    2016-10-01

    This article describes a study on the viability of using waste from the paper industry: biomass boiler ash and green liquor dregs to fabricate mortars and concretes. Both types of ash were characterized by obtaining their chemical and mineralogical composition, their organic matter content, granulometry, adsorption and other common tests for construction materials. Seven different mortars were fabricated, one for reference made up of cement, sand, and water, three in which 10, 20, or 30% of the cement was replaced by biomass ash, and three others in which 10, 20, or 30% of the cement was replaced with dregs. Test specimens were fabricated with these mortars to conduct flexural and compression tests. Flexural strength is reduced for all the mortars studied. Compressive strength increases for the mortars fabricated with biomass ash and decreases for the mortar with dregs. Finally, 5 concretes were made, one of them as a reference (neither biomass ash nor dregs added), two of them with replacements of 10 and 20% of biomass ash instead of cement and another two with replacements of 10 and 20% of dregs instead of cement. The compressive and tensile splitting strength increase when a 10% of ash is replaced and decrease in all the other cases. The modulus of elasticity always decreases.

  13. OPC recipe optimization using genetic algorithm

    Science.gov (United States)

    Asthana, Abhishek; Wilkinson, Bill; Power, Dave

    2016-03-01

    Optimization of OPC recipes is not trivial due to multiple parameters that need tuning and their correlation. Usually, no standard methodologies exist for choosing the initial recipe settings, and in the keyword development phase, parameters are chosen either based on previous learning, vendor recommendations, or to resolve specific problems on particular special constructs. Such approaches fail to holistically quantify the effects of parameters on other or possible new designs, and to an extent are based on the keyword developer's intuition. In addition, when a quick fix is needed for a new design, numerous customization statements are added to the recipe, which make it more complex. The present work demonstrates the application of Genetic Algorithm (GA) technique for optimizing OPC recipes. GA is a search technique that mimics Darwinian natural selection and has applications in various science and engineering disciplines. In this case, GA search heuristic is applied to two problems: (a) an overall OPC recipe optimization with respect to selected parameters and, (b) application of GA to improve printing and via coverage at line end geometries. As will be demonstrated, the optimized recipe significantly reduced the number of ORC violations for case (a). For case (b) line end for various features showed significant printing and filling improvement.

  14. Relation between Modulus of Elasticity and Compressive Strength of Ultrahigh-Strength Mortar with Mixed Silicon Carbide as Fine Aggregate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Ultrahigh-strength mortar mixed surface-oxidized silicon carbide as a fine aggregate was prepared by means of press-casting followed by curing in an autoclave. The relation between modulus of elasticity up to 111 GPa and compressive strength up to 360 MPa of mortar mixed silicon carbide was discussed and it was revealed that the contributions of the aggregate hardness and of the interfacial strength between the aggregate and the cement paste on the elasticity of mortar were imporant.

  15. Hydration of Portland cement with additions of calcium sulfoaluminates

    Energy Technology Data Exchange (ETDEWEB)

    Le Saout, Gwenn, E-mail: gwenn.le-saout@mines-ales.fr [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Lothenbach, Barbara [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Hori, Akihiro [DENKA Chemicals GmbH, Wehrhahn-Center, Cantadorstr. 3, D-40211 Duesseldorf (Germany); Higuchi, Takayuki [Denki Kagaku Kogyo Kabushiki Kaisha (DENKA), Omi, Itoigawa, Niigata, 949-0393 (Japan); Winnefeld, Frank [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland)

    2013-01-15

    The effect of mineral additions based on calcium aluminates on the hydration mechanism of ordinary Portland cement (OPC) was investigated using isothermal calorimetry, thermal analysis, X-ray diffraction, scanning electron microscopy, solid state nuclear magnetic resonance and pore solution analysis. Results show that the addition of a calcium sulfoaluminate cement (CSA) to the OPC does not affect the hydration mechanism of alite but controls the aluminate dissolution. In the second blend investigated, a rapid setting cement, the amorphous calcium aluminate reacts very fast to ettringite. The release of aluminum ions strongly retards the hydration of alite but the C-S-H has a similar composition as in OPC with no additional Al to Si substitution. As in CSA-OPC, the aluminate hydration is controlled by the availability of sulfates. The coupling of thermodynamic modeling with the kinetic equations predicts the amount of hydrates and pore solution compositions as a function of time and validates the model in these systems.

  16. Hydration of Portland cement with additions of calcium sulfoaluminates

    International Nuclear Information System (INIS)

    The effect of mineral additions based on calcium aluminates on the hydration mechanism of ordinary Portland cement (OPC) was investigated using isothermal calorimetry, thermal analysis, X-ray diffraction, scanning electron microscopy, solid state nuclear magnetic resonance and pore solution analysis. Results show that the addition of a calcium sulfoaluminate cement (CSA) to the OPC does not affect the hydration mechanism of alite but controls the aluminate dissolution. In the second blend investigated, a rapid setting cement, the amorphous calcium aluminate reacts very fast to ettringite. The release of aluminum ions strongly retards the hydration of alite but the C–S–H has a similar composition as in OPC with no additional Al to Si substitution. As in CSA–OPC, the aluminate hydration is controlled by the availability of sulfates. The coupling of thermodynamic modeling with the kinetic equations predicts the amount of hydrates and pore solution compositions as a function of time and validates the model in these systems.

  17. Mortar constituent of concrete under cyclic compression

    Science.gov (United States)

    Maher, A.; Darwin, D.

    1980-10-01

    The behavior of the mortar constituent of concrete under cyclic compression was studied and a simple analytic model was developed to represent its cyclic behavior. Experimental work consisted of monotonic and cyclic compressive loading of mortar. Two mixes were used, with proportions corresponding to concretes having water cement ratios of 0.5 and 0.6. Forty-four groups of specimens were tested at ages ranging from 5 to 70 days. complete monotonic and cyclic stress strain envelopes were obtained. A number of loading regimes were investigated, including cycles to a constant maximum strain. Major emphasis was placed on tests using relatively high stress cycles. Degradation was shown to be a continuous process and a function of both total strain and load history. No stability or fatigue limit was apparent.

  18. Properties of microcement mortar with nano particles

    Science.gov (United States)

    Alimeneti, Narasimha Reddy

    Carbon nanotubes (CNT) and Carbon nanofibers (CNF) are one of the toughest and stiffest materials in the world presently with extreme properties yet to be discovered in terms of elastic modulus and tensile strength. Due to the advanced properties of these materials they are being used in almost all fields of science at nanolevel and are being used in construction industry recently for improvement of material properties. Microcement is fine ground cement which as half the particle size of ordinary Portland cement. In this research the behavior of cement mortar of micro cement with the addition of nanoparticles is studied. Due to high aspect ratio and strong van der Waal forces between the particles of CNT and CNF, they agglomerate and form bundles when mixed with water, sonication method is used to mix nanoparticles with few drops of surfactant and super plasticizer. Mechanical properties such as compressive strength and flexural strength with CNT and CNF composites are examined and compared with control samples. 0.1% and 0.05 % of nanoparticles (both CNT and CNF) by the weight of cement are used in this research and 0.8% of super plasticizer by weight of cement was also used along with 0.4, 0.45 and 0.50 water cement ratios for making specimens for compression test. The compressive strength results are not satisfactory as there was no constant increase in strength with all the composites, however strength of few nanocomposites increased by a good percentage. 0.5 water cement ratio cement mortar had compressive strength of 7.15 ksi (49.3 MPa), whereas sample with 0.1% CNT showed 8.38 ksi (57.8 MPa) with 17% increase in strength after 28 days. Same trend was followed by 0.4 water cement ratio as the compressive strength of control sample was 8.89 ksi (61.3 MPa), with 0.05% of CNT strength increased to 10.90 ksi (75.2 MPa) with 23% increase in strength. 0.4 water cement ratio was used for flexural tests including 0.1%, 0.05% of CNT and 0.1%, 0.05% of CNF with 0

  19. Rietveld quantitative phase analysis of Yeelimite-containing cements

    OpenAIRE

    Álvarez-Pinazo, Gema; Cuesta, Ana; García-Maté, Marta; Santacruz, Isabel; Losilla, Enrique R.; De la Torre, Ángeles G.; León-Reina, Laura; Aranda, Miguel A. G.

    2012-01-01

    Yeelimite-containing cements are attracting attention for their tailored properties. Calcium sulfoaluminate, CSA, cements have high contents of Yeelimite and they are used for special applications. Belite calcium sulfoaluminate, BCSA or sulfobelite, cements have high contents of belite and intermediate contents of Yeelimite, and they may become an alternative to OPC. Here, we report Rietveld quantitative phase analyses for three commercially available CSA clinkers, one CSA cement,...

  20. Energetically Modified Cement (EMC) - Performance Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ronin, Vladimir; Elfgren, Lennart [Luleaa Univ. of Technology (Sweden). Centre for High Performance Cement

    2003-03-01

    Energetically Modified Cements, EMC, made of intensively milled cement (50%) and fillers (50%) of quartz or fly ash have been compared to blends of Ordinary Portland Cement, OPC, and fillers. The EMCs have better properties than other blends and are comparable to unblended OPC. This remarkable fact can probably be explained as follows. The grinding process reduces the size of both cement grains and fillers. This combined with the creation of micro defects gives the ground cement a very high degree of hydration. The increased early hydration and a better distribution of hydration products results in an extensive pore size refinement of the hardened binder. This pore size refinement leads to a favorably reduced permeability and diffusivity and very good mechanical properties.

  1. Processing and characterisation of calcium sulphoaluminate (CSA) eco-cements with tailored performances

    OpenAIRE

    García-Maté, Marta

    2014-01-01

    Climate change mitigation usually involves the reduction of greenhouse gases emissions, such as carbon dioxide (CO2). Every tonne of Ordinary Portland Cement (OPC) produces about one tonne of CO2. Consequently, OPC accounts for 5-6% of anthropogenic CO2 emissions and for 4% of total global warming. Due to these environmental problems the industry of building materials is under increasing pressure to reduce the energy used in the production of OPC and the greenhouse gas emissions. Hence, t...

  2. Oyster shell as substitute for aggregate in mortar.

    Science.gov (United States)

    Yoon, Hyunsuk; Park, Sangkyu; Lee, Kiho; Park, Junboum

    2004-06-01

    Enormous amounts of oyster shell waste have been illegally disposed of at oyster farm sites along the southern coast of Korea. In this study to evaluate the possibility of recycling this waste for use as a construction material, the mechanical characteristics of pulverized oyster shell were investigated in terms of its potential utilization as a substitute for the aggregates used in mortar. The unconfined compressive strengths of various soil mortar specimens, with varying blending ratios of cement, water and oyster shell, were evaluated by performing unconfined compression tests, and the results were compared with the strengths of normal cement mortar made with sand. In addition, the effect of organic chemicals on the hardening of concrete was evaluated by preparing ethyl-benzene-mixed mortar specimens. The long-term strength improvement resulting from the addition of fly ash was also examined by performing unconfined compression tests on specimens with fly-ash content. There was no significant reduction in the compressive strength of the mortars containing small oyster shell particles instead of sand. From these test data, the possible application of oyster shells in construction materials could be verified, and the change in the strength parameters according to the presence of organic compounds was also evaluated.

  3. Strength of Ternary Blended Cement Sandcrete Containing Afikpo Rice Husk Ash and Saw Dust Ash

    Directory of Open Access Journals (Sweden)

    L. O. Ettu

    2013-01-01

    Full Text Available This work investigated the compressive strength of ternary blended cement sandcrete containing Afikpo rice husk ash (RHA and sawdust ash (SDA. 105 sandcrete cubes of 150mm x 150mm x 150mm were produced with OPC-RHA binary blended cement, 105 with OPC-SDA binary blended cement, and 105 with OPC-RHA-SDA ternary blended cement, each at percentage OPC replacement with pozzolan of 5%, 10%, 15%, 20%, and 25%. Three cubes for each percentage replacement of OPC with pozzolan and the control were tested for saturated surface dry bulk density and crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, and 90 days of curing. The 90-day strengths obtained from ternary blending of OPC with equal proportions of RHA and SDA were 11.80N/mm2for 5% replacement, 11.20N/mm2for 10% replacement, 10.60N/mm2for 15% replacement, 10.00N/mm2for 20% replacement, and 9.10N/mm2for 25% replacement, while that of the control was 10.90N/mm2. This suggests that very high sandcrete strength values could be obtained with OPCRHA-SDA ternary blended cement with richer mixes, high quality control, and longer days of hydration. Thus, OPC-RHA-SDA ternary blended cement sandcrete could be used for various civil engineering and building works, especially where early strength is not a major requirement.

  4. Use of glazed ceramic waste as additive in mortar and the mathematical modelling of its strength.

    Science.gov (United States)

    Altin, Zehra Gulten; Erturan, Seyfettin; Tepecik, Abdulkadir

    2008-04-01

    This study investigated the reusability of waste material from the tile manufacturing industry as an alternative material to natural pozzolan trass. Yield strength values of mortar made from Portland cement (CEM 142.5), were measured by adding glazed ceramic waste and trass at various weight ratios (5 to 40%). The test results proved that the strength values at 2, 7, and 28 days gave good results for concentrations of waste materials less than 5-10% in the cement. A decrease in strength was observed at higher concentrations. Mathematical modelling results showed a logarithmic correlation between the mortar strength and weight fraction of cement.

  5. Use of glazed ceramic waste as additive in mortar and the mathematical modelling of its strength.

    Science.gov (United States)

    Altin, Zehra Gulten; Erturan, Seyfettin; Tepecik, Abdulkadir

    2008-04-01

    This study investigated the reusability of waste material from the tile manufacturing industry as an alternative material to natural pozzolan trass. Yield strength values of mortar made from Portland cement (CEM 142.5), were measured by adding glazed ceramic waste and trass at various weight ratios (5 to 40%). The test results proved that the strength values at 2, 7, and 28 days gave good results for concentrations of waste materials less than 5-10% in the cement. A decrease in strength was observed at higher concentrations. Mathematical modelling results showed a logarithmic correlation between the mortar strength and weight fraction of cement. PMID:18578160

  6. Steelmaking slag as aggregate for mortars: effects of particle dimension on compression strength.

    Science.gov (United States)

    Faraone, Nicola; Tonello, Gabriele; Furlani, Erika; Maschio, Stefano

    2009-11-01

    The present paper reports on the results of some experiments obtained from the production, hydration and subsequent measurement of the mechanical properties of several mortars prepared using a commercial CII/B-LL Portland cement, steelmaking slag, superplasticizer and water. Relevant parameters for the mortar preparation are the weight ratios of cement/water, the weight ratio superplasticizer/cement and between fine and granulated coarse particles. It has been demonstrated that optimisation of such parameters leads to the production of materials with mechanical properties suitable for civil engineering applications. Moreover, materials with improved compressive strength can be prepared by the use of slag containing extensive amounts of large particles.

  7. Strength of Blended Cement Sandcrete & Soilcrete Blocks Containing Cassava Waste Ash and Plantain Leaf Ash

    Directory of Open Access Journals (Sweden)

    L. O. Ettu

    2013-01-01

    Full Text Available This work investigated the compressive strength of binary and ternary blended cement sandcrete and soilcrete blocks containing cassava waste ash (CWA and plantain leaf ash (PLA. 135 solid sandcrete blocks and 135 solid soilcrete blocks of 450mm x 225mm x 125mm were produced with OPC-CWA binary blended cement, 135 with OPC-PLA binary blended cement, and 135 with OPC-CWA-PLA ternary blended cement, each at percentage OPC replacement with pozzolan of 5%, 10%, 15%, 20%, and 25%.Three sandcrete blocks and three soilcrete blocks for each OPC-pozzolan mix and the control were crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, 90, 120, and 150 days of curing. Sandcrete and soilcrete block strengths from binary and ternary blended cements were found to be higher than the control values beyond 90 days of hydration. The 150-day strength values for OPC-CWA-PLA ternary blended cement sandcrete and soilcrete blocks were respectively 5.90N/mm2and 5.10N/mm2for 5% replacement, 5.80N/mm2and 4.95N/mm2for 10% replacement, 5.65N/mm2and 4.85N/mm2for 15% replacement, 5.60N/mm2and 4.75N/mm2for 20% replacement, and 5.25N/mm2and 4.65N/mm2for 25% replacement; while the control values were 5.20N/mm2and 4.65N/mm2. Thus, OPC-CWA and OPC-PLA binary blended cements as well as OPC-CWA-PLA ternary blended cement could be used in producing sandcrete and soilcrete blocks with sufficient strength for use in building and minor civil engineering works where the need for high early strength is not a critical factor.

  8. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.;

    1999-01-01

    modelled on Fick's law modified by a term for chloride binding. Inclusion of chloride binding significantly improves the profile shape of the modelled ingress profiles. The presence of fine aggregate and formation of interfacial transition zones at paste-aggregate boundaries does not significantly affect...

  9. The effects of different types of nano-silicon dioxide additives on the properties of sludge ash mortar.

    Science.gov (United States)

    Luo, Huan-Lin; Chang, Wei-Che; Lin, Deng-Fong

    2009-04-01

    To improve the drawbacks caused by the sludge ash replacement in mortar, the previous studies have shown that the early strength and durability of sludge ash/cement mortar are improved by adding nano-silicon dioxide (nano-SiO2) to mortar. In this article, three types of nano-SiO2--SS, HS, and SP (manufacturer code names)--were applied to sludge ash/cement mixture to make paste or mortar specimens. The object is to further extend the recycle of the sludge ash by determining the better type of nano-SiO2 additive to improve properties of sludge ash/ cement paste or mortar. The cement was replaced by 0, 10, 20, and 30% of sludge ash, and 0 and 2% of nano-SiO2 additives were added to the sludge ash paste or mortar specimens. Tests such as setting time, compressive strength, scanning electron microscopy, X-ray diffraction, nuclear magnetic resonance, and thermogravimetric analysis/differential thermal analysis were performed in this study. Test results show that nano-SiO2 additives can not only effectively increase the hydration product (calcium silicate hydrate [C-S-H] gel), but also make the crystal structure denser. Among the three types of nano-SiO2 additive, the SS type can best improve the properties of sludge ash/cement paste or mortar, followed by the SP and HS types.

  10. Use of olive biomass fly ash in the preparation of environmentally friendly mortars.

    Science.gov (United States)

    Cruz-Yusta, Manuel; Mármol, Isabel; Morales, Julián; Sánchez, Luis

    2011-08-15

    The incorporation of fly ash from olive biomass (FAOB) combustion in cogeneration plants into cement based mortars was explored by analyzing the chemical composition, mineralogical phases, particle size, morphology, and IR spectra of the resulting material. Pozzolanic activity was detected and found to be related with the presence of calcium aluminum silicates phases. The preparation of new olive biomass fly ash content mortars is effective by replacing either CaCO(3) filler or cement with FAOB. In fact, up to 10% of cement can be replaced without detracting from the mechanical properties of a mortar. This can provide an alternative way to manage the olive biomass fly ash as waste produced in thermal plants and reduce cement consumption in the building industry, and hence an economically and environmentally attractive choice.

  11. Properties of wastepaper sludge in geopolymer mortars for masonry applications.

    Science.gov (United States)

    Yan, Shiqin; Sagoe-Crentsil, Kwesi

    2012-12-15

    This paper presents the results of an investigation into the use of wastepaper sludge in geopolymer mortar systems for manufacturing construction products. The investigation was driven by the increasing demand for reuse options in paper-recycling industry. Both fresh and hardened geopolymer mortar properties are evaluated for samples incorporating dry wastepaper sludge, and the results indicate potential end-use benefits in building product manufacture. Addition of wastepaper sludge to geopolymer mortar reduces flow properties, primarily due to dry sludge absorbing water from the binder mix. The average 91-day compressive strength of mortar samples incorporating 2.5 wt% and 10 wt% wastepaper sludge respectively retained 92% and 52% of the reference mortar strength. However, contrary to the normal trend of increasing drying shrinkage with increasing paper sludge addition to Portland cement matrices, the corresponding geopolymer drying shrinkage decreased by 34% and 64%. Equally important, the water absorption of hardened geopolymer mortar decreased with increasing paper sludge content at ambient temperatures, providing good prospects of overall potential for wastepaper sludge incorporation in the production of building and masonry elements. The results indicate that, despite its high moisture absorbance due to the organic matter and residual cellulose fibre content, wastepaper sludge appears compatible with geopolymer chemistry, and hence serves as a potential supplementary additive to geopolymer cementitious masonry products.

  12. 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

  13. 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.

  14. Strength and shrinkage properties of mortar containing a nonstandard high-calcium fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Cengiz Duran Atis; Alaettin Kilic; Umur Korkut Sevim [Cukurova University, Balcali-Adana (Turkey). Engineering and Architecture Faculty

    2004-01-01

    A laboratory study was undertaken to assess the compressive and flexural tensile strength and drying shrinkage properties of mortar mixtures containing high-calcium nonstandard Afsin-Elbistan fly ash (FA). Possibility of using Afsin-Elbistan FA in cement-based materials as shrinkage-reducing or compensation agent was also discussed. Five mortar mixtures including control Portland cement (PC) and FA mortar mixtures were prepared. FA replaced the cement on mass basis at the replacement ratios of 10%, 20%, 30% and 40%. Water-cementitious materials ratio was 0.4 for all mixtures. The mixtures were cured at 65% relative humidity and 20{+-}2{sup o}C. The compressive and flexural tensile strength and drying shrinkage values of the mortar mixtures were measured. The results show that Afsin-Elbistan FA reduced drying shrinkage of the mortar by 40%. Therefore, it was concluded that Afsin-Elbistan FA can be used as a shrinkage-reducing agent. The mortar containing 40% FA expanded. This indicates that Afsin-Elbistan FA may be utilized to compensate drying shrinkage of cement-based materials.

  15. 石灰-水泥系外墙防水装饰砂浆与外墙外保温系统适应性研究%The adaptive research of lime-cement waterproof decorative mortar for exterior wall and exterior insulation system

    Institute of Scientific and Technical Information of China (English)

    韩方晖; 王栋民; 许晨阳; 刘晓斌; 刘天德

    2012-01-01

    To make lime-cement waterproof decorative mortar for exterior wall which successes through chemical modification technology to be widely applied in exterior insulation system, it must have good adaptability with exterior insulation system. This paper through establishing force diagram of facing external wall thermal insulation and adopting ESP external wall thermal insulation to be used in high-rise building)analyzing and calculating the earthquake effect by level, wind load and both combination effect and vertical stress gravity and bond force: meanwhile,on the basis of the calculation method to calculate the force of the 100 m-high high-rise building top exterior insulation system in the Beijing center: furthermore, calculating the force of facing external wall thermal insulation when the exterior wall facing is ceramic tile, coating and carrying on the comparison. Results indicate: it is safe when the exterior wall facing is lime-cement waterproof decorative mortar for exterior wall in high-rise exterior insulation system; by the size of the load is for ceramic tile > lime-cement waterproof decorative mortar for exterior wall > coating, in comprehensive comparison, lime-cement waterproof decorative mortar for exterior wall has superiority.%要使通过化学改性技术研制成功的石灰-水泥系外墙防水装饰砂浆在外墙外保温系统中得到广泛应用,其必须与外墙外保温系统有很好的适应性.通过建立饰面外墙外保温系统受力图,对采用膨胀聚苯板作为高层建筑外墙外保温时,所受水平地震作用、风荷载和两者组合效应及竖直方向受力重力和压剪粘结力分析计算;同时,依据这些计算方法计算了北京市中心高为100m的高层建筑顶部外墙外保温系统受力情况;计算了外墙饰面为瓷砖、涂料时外墙外保温系统的受力情况,并对其进行比较.结果表明:外墙饰面为石灰-水泥系外墙防水装饰砂浆时应用于高层外

  16. Modelling the effects of waste components on cement hydration

    NARCIS (Netherlands)

    Eijk, van R.J.; Brouwers, H.J.H.

    2001-01-01

    Ordinary Portland Cement (OPC) is often used for the solidification/stabilization (S/S) of waste containing heavy metals and salts. These waste components will precipitate in the form of insoluble compounds on to unreacted cement clinker grains preventing further hydration. In this study the long te

  17. Modelling the effects of waste components on cement hydration

    NARCIS (Netherlands)

    Eijk, van R.J.; Brouwers, H.J.H.

    2000-01-01

    Ordinary Portland Cement (OPC) is often used for the Solidification/Stabilization (S/S) of waste containing heavy metals and salts. These waste componenents will precipitate in the form of insoluble compounds onto unreacted cement clinker grains preventing further hydration. In this study the long t

  18. INVESTIGATING EFFECTS OF INTRODUCTION OF CORNCOB ASH INTO PORTLAND CEMENTS CONCRETE: MECHANICAL AND THERMAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Antonio Price

    2014-01-01

    Full Text Available The purpose of this study was to evaluate the benefits of replacing Ordinary Portland Cement (OPC with Corncob Ash (CCA blended cements. The cement industry contributes considerable amount of Carbon Dioxide (CO2 emissions into the atmosphere. The main contribution of CO2 emissions from cement production results from the process of creating Calcium Oxide (CaO from limestone (CaCO3 commonly known as the calcination process. Blending OPC with a pozzolanic material will assist in the reduction of CO2 emissions due to calcination as well as enhance the quality of OPC. There are various pozzolanic materials such as fly ash, rice husk, silica fume and CCA that could be promising partial replacement for OPC. In this study, CCA will serve as the primary blending agent with OPC. An experiment was performed to designate an appropriate percentage replacement of CCA that would comply with specific standards of cement production. The experimental plan was designed to analyze compressive strength, workability and thermal performance of various CCA blended cements. The data from the experiment indicates that up to 10% CCA replacement could be used in cement production without compromising the structural integrity of OPC. In addition, it was found that the compressive strength and workability of the resulting concrete could be improved when CCA is added to the mixtures. Furthermore, it was shown that the introduction of 10% CCA can lead to significant reduction in thermal conductivity of the mixture.

  19. Caracterização física e mecânica de argamassas à base de cimento Portland e cinza de casca de arroz residual Physical and mechanical characterization on Portland cement mortar with rice husk ash addition

    Directory of Open Access Journals (Sweden)

    Michelle S Rodrigues

    2010-04-01

    Full Text Available A casca de arroz, utilizada como fonte de energia em indústrias de beneficiamento de arroz, converte-se, depois da queima, em uma cinza residual. Esse resíduo, ainda sem um destino adequado, é muitas vezes depositado em grandes áreas abertas e provoca elevado impacto ambiental. Este trabalho teve como objetivo avaliar a viabilidade de utilização da cinza de casca de arroz (CCA residual na produção de argamassas, como substituta parcial do cimento. A caracterização da CCA foi realizada por meio da análise de fluorescência de raios-X (composição química, análise do teor de carbono e difração de raios-X; também foi realizada análise granulométrica a laser. Os corpos de prova foram submetidos a dois tipos de exposição: ambientes externo e interno, com duração máxima de cinco meses. Foram realizados os ensaios de resistência à compressão simples e não destrutivo (velocidade do pulso ultrassônico - VPU. Embora as argamassas tenham apresentado bom desempenho mecânico, os ensaios de pozolanicidade indicaram que a cinza de casca de arroz residual utilizada não é uma pozolana, mas pode ser utilizada em matrizes cimentícias como material inerte (filler.Rice husk, employed as an energy source at milling industries in Brazil generates, after burning, a dark ash. This residue is not yet conveniently disposed, being currently dumped on large areas, causing environmental problems. This research intended to evaluate the applications of residual rice husk ashes (RHA as a partial replacement of cement for mortar production. Rice husk ash was chemically characterized through X-ray fluorescence, determination of carbon content, X-ray diffraction, and laser granulometric analysis. Mortar specimens were submitted to two different exposure conditions: internal and external environments at a maximum period of five months. Physical-mechanical testing were compressive strength and ultrasonic pulse velocity (UPV. Although presenting good

  20. InfIuence of curing conditions on the performance of persuIphated phosphogypsum-sIag cement mortar%养护条件对过硫磷石膏矿渣水泥砂浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    曾潇; 水中和; 丁沙; 田素芳; 陈飞翔

    2015-01-01

    PPSC is a kind of new cementing materials.Itˊs a mixture of 40%~50%phosphogypsum(PG),40%~50%ground granulated blast-furnace slag(GGBFS),2%steel slag(SS)and 4% portland cement clinker.The influence of thermostatic temperature,delay time and thermostatic period on the strength of PPSC mortar was studied by using orthogonal design testing method. Based on the testing technology of XRD and SEM,the influence of thermostatic temperature on the strength and microstructure of PPSC mortar was also studied.The results indicated that thermostatic temperature has a significant influence on the strength and microstructure of PPSC mortar under steam curing,and 40 ℃ of thermostatic temperature is favorable for its strength and microstructure.%过硫磷石膏矿渣水泥( PPSC)是由40%~50%磷石膏、40%~50%粒化高炉矿渣、2%钢渣以及4%水泥熟料混合而成的一种新型胶凝材料。通过正交试验设计研究了恒温温度、静停时间和保温时间对过硫磷石膏矿渣水泥砂浆强度的影响,并通过X射线衍射( XRD)和扫描电子显微镜( SEM)测试技术初步探讨了恒温温度对蒸养过硫磷石膏矿渣水泥砂浆强度和微观结构的影响。试验结果表明:在蒸汽养护条件下,恒温温度对强度的影响最为显著,静停时间和养护时间影响较小,高温不利于其强度发展,40℃为适宜的恒温温度。

  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. Sulfate resistance of ordinary Portland cement with fly ash

    OpenAIRE

    Irassar, Edgardo F.; Batic, Oscar R.

    1989-01-01

    Low calcium fly ash has demonstrated to be an effective pozzolan to improve sulfate resistance of ordinary portland cement (type I). In this paper physico-chemical effects that produce this pozzolan in the mortar exposed to sulfate attack are studied. Dilution and dispersion affects are analyzed using mixes of cement with an inert mineral admixture. Mineralogical changes of mortar are studied using X-ray diffraction and the help of scanning electron microscope. The results show that fly...

  3. The physical, chemical, and microscopic properties of masonry mortars from Alhambra Palace (Spain in reference to their earthquake resistance

    Directory of Open Access Journals (Sweden)

    Hanifi Binici

    2016-03-01

    Full Text Available Al-Andalus mortar is an ancient binding material (lime mortar that was used for centuries in numerous historical buildings in Al-Andalus, Granada (Spain. The physico-chemical and microscopic properties of Al-Andalus mortars in Granada were studied as part of an investigation into the mineral raw materials present in the territory of Spain. Scanning electron microscope and X-ray diffraction analyses of eight main types of mortars were performed to show the presence of calcite, gypsum, quartz, and muscovite minerals with organic fibers. Chemical analyses of the specimens showed that high SiO2+Al2O3+Fe2O3 contents yielded high values of hydraulicity and cementation indices. A significant result of this study was that mortars with high hydraulicity and cementation indices have high mechanical strengths. This characteristic may be the main reason for the earthquake resistance of the historical Alhambra Palace.

  4. Deterioration of limestone aggregate mortars by liquid sodium in fast breeder reactor environment

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed Haneefa, K., E-mail: mhkolakkadan@gmail.com [Department of Civil Engineering, IIT Madras, Chennai (India); Santhanam, Manu [Department of Civil Engineering, IIT Madras, Chennai (India); Parida, F.C. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2014-08-15

    Highlights: • Limestone mortars were exposed to liquid sodium exposure at 550 °C. • Micro-analytical techniques were used to characterize the exposed specimens. • The performance of limestone mortar was greatly influenced by w/c. • The fundamental degradation mechanisms of limestone mortars were identified. - Abstract: Hot liquid sodium at 550 °C can interact with concrete in the scenario of an accidental spillage of sodium in liquid metal cooled fast breeder reactors. To protect the structural concrete from thermo-chemical degradation, a sacrificial layer of limestone aggregate concrete is provided over it. This study investigates the fundamental mechanisms of thermo-chemical interaction between the hot liquid sodium and limestone mortars at 550 °C for a duration of 30 min in open air. The investigation involves four different types of cement with variation of water-to-cement ratios (w/c) from 0.4 to 0.6. Comprehensive analysis of experimental results reveals that the degree of damage experienced by limestone mortars displayed an upward trend with increase in w/c ratios for a given type of cement. Performance of fly ash based Portland pozzolana cement was superior to other types of cements for a w/c of 0.55. The fundamental degradation mechanisms of limestone mortars during hot liquid sodium interactions include alterations in cement paste phase, formation of sodium compounds from the interaction between solid phases of cement paste and aggregate, modifications of interfacial transition zone (ITZ), decomposition of CaCO{sub 3}, widening and etching of rhombohedral cleavages, and subsequent breaking through the weakest rhombohedral cleavage planes of calcite, staining, ferric oxidation in grain boundaries and disintegration of impurity minerals in limestone.

  5. Microstructure and mechanical performance of modified mortar using hemp fibres and carbon nanotubes

    KAUST Repository

    Hamzaoui, Rabah

    2014-04-01

    Mechanical performance of modified mortar using hemp fibres is studied following various processing conditions. Hemp fibres combined with carbon nanotubes (CNT) are introduced in mortar and their effect is studied as function of curing time. The cement phase is replaced by different percentages of dry or wet hemp fibres ranging from 1.1. wt% up to 3.1. wt% whereas carbon nanotubes are dispersed in the aqueous solution. Our experimental results show that compressive and flexural strengths of wet fibres modified mortar are higher than those for dry hemp-mortar material. The achieved optimal percentage of wet hemp fibres is 2.1. wt% allowing a flexural strength higher than that of reference mortar. The addition of an optimal CNT concentration (0.01. wt%) combined with wet hemp has a reinforcing effect which turns to be related to an improvement of compressive and flexural strengths by 10% and 24%, respectively, in comparison with reference condition. © 2013 Elsevier Ltd.

  6. OPC Data Acquisition Server for CPDev Engineering Environment

    Science.gov (United States)

    Rzońca, Dariusz; Sadolewski, Jan; Trybus, Bartosz

    OPC Server has been created for the CPDev engineering environment, which provides classified process data for OPC client applications. Hierarchical Coloured Petri nets are used at design stage to model communications of the server with CPDev target controllers. Implementation involves an universal interface for acquisition data via different communication protocols like Modbus or .NET Remoting.

  7. Concentration Boundary Layer Model of Mortar Corrosion by Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    SONG Zhigang; ZHANG Xuesong; MIN Hongguang

    2011-01-01

    A long time immersion experiment of mortar specimens is carried out to investigate their degradation mechanism by sulfuric acid. Water-cement ratios of mortar are ranging from 0.5 to 0.7 and the pH value of sulfuric acid is 3.5 and 4.0 respectively. The pH meter is used to monitor the soak solution and the titration sulfuric acid with given concentration is added to maintain original pH value, through which the acid consumption of mortar is recorded. A theoretical reaction rate model is also proposed based on concentration boundary layer model. The results show that theoretical model fits the experimental results well and the corrosion mechanism can be modeled by a diffusion process accompanied with an irreversible chemical reaction when pH value of soak solution is no less than 3.5.

  8. Application of micromechanics to the characterization of mortar by ultrasound.

    Science.gov (United States)

    Hernández, M G; Anaya, J J; Izquierdo, M A G; Ullate, L G

    2002-05-01

    Mechanical properties of concrete and mortar structures can be estimated by ultrasonic non-destructive testing. When the ultrasonic velocity is known, there are standardized methods based on considering the concrete a homogeneous material. Cement composites, however, are heterogeneous and porous, and have a negative effect on the mechanical properties of structures. This work studies the impact of porosity on mechanical properties by considering concrete a multiphase material. A micromechanical model is applied in which the material is considered to consist of two phases: a solid matrix and pores. From this method, a set of expressions is obtained that relates the acoustic velocity and Young's modulus of mortar. Experimental work is based on non-destructive and destructive procedures over mortar samples whose porosity is varied. A comparison is drawn between micromechanical and standard methods, showing positive results for the method here proposed.

  9. Performance of Polymer Modified Mortar with Different Dosage of Polymeric Modifier

    OpenAIRE

    Ganesan Shankar; Othuman Mydin Md Azree; Sani Norazmawati Md.; Che Ani Adi Irfan

    2014-01-01

    Polymer modified mortar system is defined as hydraulic cement combined at the time of mixing with organic polymers that are dispersed or re-dispersed in water, with or without aggregates. The compressive strength and flexural strength of polymer modified mortar obtained at early age are low and it required prolong curing period for the strength enhancement. In order to enhance the mechanical properties of cementitious mixture as well as its durability, hybridization of polymeric modifiers are...

  10. Effect of carbonation on the chloride diffusion of mortar specimens exposed to cyclic wetting and drying

    OpenAIRE

    Malheiro, Raphaele Lira Meireles Castro; Camões, Aires; Ferreira, Rui Miguel; Meira, Gibson; Amorim, M. T. Pessoa de

    2014-01-01

    Carbonation and chloride ingress are the two main causes of corrosion in reinforced concrete structures. Despite the combined action of these mechanisms being a reality, there is little research on the effect of carbonation on the chloride diffusion in concrete. This work intends to study the influence of carbonation on chloride diffusion of mortar specimens. Cubic mortar specimens were cast with 0.55 of water-cement ratio. After curing, the specimens were subjected to 56 days of wetting and ...

  11. Research on the Correlation between Pore Structures and the Strength of Cement Mortar with Pozzolanic%火山灰水泥砂浆孔结构与其强度相关性的研究

    Institute of Scientific and Technical Information of China (English)

    张凌; 孙海燕; 龚爱民; 张国林

    2013-01-01

    In this paper, the strength of mortars with the 15%, 30% and 45% dosages pozzolanic and the 7 d, 28 d and 60 d curing ages is studied. Meanwhile, based on the absorption-hydrodynamic method, pore structure of mortars with the different dosages pozzolanic is tested by the parameters of pore homogeneity and average pore diameter when at different curing ages. When a certain a-mount pozzolanic is mixed, pore structure of mortars can be optimized and denser. That is, the optimum parameters value of pore structure can be achieved when pozzolanic dosage increases to 30%, but after increasing continuously to exceed 45%, pore structure of mortars begin to be deteriorated. There is a better correlation between the parameters of pore structured and λ-) and the strength of mortars with different pozzolanic dosages at different curing ages.%研究了15%、30%和45%3种火山灰掺量和7d、28 d和60d3个养护龄期对水泥砂浆强度的影响,并基于吸水动力学法以孔径均匀性和平均孔径两个参数,研究了不同水化龄期下,3种掺量火山灰对水泥砂浆孔结构的影响规律.结果表明:不同掺量的火山灰水泥砂浆试件,随火山灰掺量在增加,其最佳活性效应位置点和孔结构均出现在30%时,向水泥砂浆中掺入一定量的火山灰可以细化水化浆体的孔结构,当火山灰的掺量不超过30%时,水泥石的平均孔径参数均随火山灰的掺量增加而减小,且孔径均匀性提高,对水泥砂浆的孔结构改善效果比较好,当其掺量增加到45%后,水泥砂浆的孔结构反而又开始呈现出劣化趋势.不同水化龄期时各掺量粉煤灰砂浆孔结构参数(α和λ)与其强度试验结果间相关性较好.

  12. A Study on the Properties of Carbon Black Mortar Using Granulated Blast Furnace Slag and Polymer.

    Science.gov (United States)

    Jang, Hong-Seok; Jeon, Ui-Hyeon; So, Seung-Young

    2015-11-01

    White Portland Cement (WPC) and inorganic pigment have been used in colored concrete, but there are some physical problems such as increases in efflorescence, and poor workability and low economics. The aim of this study was to investigate the effects of GBFS and polymer (methyl cellulose) on the physical properties of carbon black mortar. For this purpose, a flow test, compressive strength test and color evaluation and was carried out on cement mortar mixed with polymer by changing the proportion of cement and ratio of GBFS. The results show that the addition of polymer influences significantly the color value efficiency in colored mortar. This is due to the reduction of overall amount of micro pore. This polymer films prevent the transport of soluble calcium towards the surface, and decreases efflorescence. And the flow of colored mortar was increased in proportion to the addition rate of the GBFS. In addition the strength of colored mortars with GBFS at the long-term aged (after 28 days) was higher than that of the general WPC mortar, although its strength was developed slowly at the early ages. PMID:26726652

  13. A Study on the Properties of Carbon Black Mortar Using Granulated Blast Furnace Slag and Polymer.

    Science.gov (United States)

    Jang, Hong-Seok; Jeon, Ui-Hyeon; So, Seung-Young

    2015-11-01

    White Portland Cement (WPC) and inorganic pigment have been used in colored concrete, but there are some physical problems such as increases in efflorescence, and poor workability and low economics. The aim of this study was to investigate the effects of GBFS and polymer (methyl cellulose) on the physical properties of carbon black mortar. For this purpose, a flow test, compressive strength test and color evaluation and was carried out on cement mortar mixed with polymer by changing the proportion of cement and ratio of GBFS. The results show that the addition of polymer influences significantly the color value efficiency in colored mortar. This is due to the reduction of overall amount of micro pore. This polymer films prevent the transport of soluble calcium towards the surface, and decreases efflorescence. And the flow of colored mortar was increased in proportion to the addition rate of the GBFS. In addition the strength of colored mortars with GBFS at the long-term aged (after 28 days) was higher than that of the general WPC mortar, although its strength was developed slowly at the early ages.

  14. Pullout behavior of steel fibers from cement-based composites

    DEFF Research Database (Denmark)

    Shannag, M. Jamal; Brincker, Rune; Hansen, Will

    1997-01-01

    fiber reinforcement. The parameters investigated included a specially designed high strength cement based matrix called Densified Small Particles system (DSP), a conventional mortar matrix, fiber embeddment length, and the fiber volume fraction. The mediums from which the fiber was pulled included...... a control mortar mix without fibers, a mortar mix with 3, and 6 percent fibers by volume. The results indicate that: (1) The dense DSP matrix has significantly improved interfacial properties as compared to the conventional mortar matrix. (2) Increasing the fiber embeddment length and the fiber volume...

  15. Preparation and Properties of a New Composite of Epoxy Emulsion(EEM)Modified Cement

    Institute of Scientific and Technical Information of China (English)

    XIAO Liguang; JIN Yujie; GU Lixia

    2009-01-01

    High performance cement based composite materials was prepared by adding epoxy emulsion.The epoxy emulsion was synthesized with epoxy phosphoric acid ester and poly-glycol in laboratory.This epoxy emulsion has advantages over other emulsion,such as dehydrated slightly,and well film formation abilities.The mechanical properties, corruptness resistance and structure of ep-oxy emulsion modified cement mortars were studied.Experimental results show that the mechanical properties of modified cement mortars are slightly increased with increasing epoxy emulsion content, especially the flexure strength.The corruptness resistance of all modified mortars is better than the unmodified mortar.The polymer film forms the bridge phases between the matrix and the aggregate regions,and forms a three-dimension structure in the cement hydration system,which improves the mechanical properties of modified mortars.

  16. DURABILITY OF NATURAL POZZOLAN-BASED MORTAR EXPOSED TO SULFATE ATTACK

    Directory of Open Access Journals (Sweden)

    L. Laoufi

    2016-05-01

    Full Text Available Cement is a strategic commodity in the civil engineering for the construction of reinforced concrete structures. But its production generates around 5% of toxic gases such as CO2 responsible for environmental degradation. Furthermore, cement industry is a consumer sector of non-renewable energy. The use in the cement of natural additions is a solution to reduce the CO2 gas and the cost of production. The purpose of this work is the study of a sustainable building material: natural pozzolan Beni-saf (PNB incorporated to mortars exposed to sulfate attack (5% Na2SO4. The loss of mass, monitoring the pH reading of each attack solution as well as specimens dimensions are different tests to study the durability of mortars made with 10, 20 and 30% of natural pozzolan. The result derived from this research is that pozzolan improves mortars resistance to sodium sulfate environment.

  17. Chloride ion transport performance in slag mortar under fatigue loading

    Institute of Scientific and Technical Information of China (English)

    WANG CaiHui; SUN Wei; JIANG JinYang; HAN JianDe; YE BangTu

    2012-01-01

    The transport performance of chloride ion in slag cement mortar was investigated experimentally.In the self-designed experiment,fatigue loading was coupled simultaneously with ion transportation process,the diffusion law of chloride ion was obtained by titration and the AE (acoustic emission) technique was employed to detect the real-time damage distribution in the mortar specimen.The results for fatigue stress levels of 0.3,0.4 and 0.5 and slag contents of 0,10%,30% and 50% showed that fatigue loading accelerated the diffusion of chloride ion in mortar and the acceleration effect increased with the increase in stress levels.Slag addition was found to improve anti-chloride ion erosion performance effectively with the best substitution level at 30%,because the inhibition effect of slag on chloride ion diffusion diminished when the slag content exceeded 30%.The comparative experiments indicated that dynamic load has a significant effect on the transport performance of chloride ion in slag cement mortar.

  18. A new geopolymeric binder from hydrated-carbonated cement

    OpenAIRE

    Paya Bernabeu, Jorge Juan; Borrachero Rosado, María Victoria; Monzó Balbuena, José Mª; Soriano Martinez, Lourdes; Mitsuuchi Tashima, Mauro

    2012-01-01

    This paper evaluates the use of hydrated Portland cement as the raw material in the production of geopolymers. The silicon and aluminium oxides needed for the geopolymerization process were produced by the carbonation of hydrated Portland cement, which transforms CSH and CAH (Portland cement hydrates) into silica and alumina gels. Hydrated-carbonated Portland cement was alkali activated with a NaOH/waterglass solution. Pastes and mortars were prepared, and micro-structural and mechanical prop...

  19. NMR relaxometry study of plaster mortar with polymer additives

    Energy Technology Data Exchange (ETDEWEB)

    Jumate, E.; Manea, D. [Technical University of Cluj-Napoca, Faculty of Civil Engineering. 15 C Daicoviciu Str., 400020, Cluj-Napoca (Romania); Moldovan, D.; Fechete, R. [Technical University of Cluj-Napoca, Department of Physics and Chemistry, 25 G. Baritiu Str., 400027, Cluj-Napoca (Romania)

    2013-11-13

    The cement mixed with water forms a plastic paste or slurry which stiffness in time and finally hardens into a resistant stone. The addition of sand aggregates, polymers (Walocel) and/or calcium carbonate will modify dramatically the final mortar mechanic and thermal properties. The hydration processes can be observed using the 1D NMR measurements of transverse T{sub 2} relaxation times distributions analysed by a Laplace inversion algorithm. These distributions were obtained for mortar pasta measured at 2 hours after preparation then at 3, 7 and 28 days after preparation. Multiple components are identified in the T{sub 2} distributions. These can be associated with the proton bounded chemical or physical to the mortar minerals characterized by a short T{sub 2} relaxation time and to water protons in pores with three different pore sizes as observed from SEM images. The evaporation process is faster in the first hours after preparation, while the mortar hydration (bonding of water molecules to mortar minerals) can be still observed after days or months from preparation. Finally, the mechanic resistance was correlated with the transverse T{sub 2} relaxation rates corresponding to the bound water.

  20. The colour potentials of SSA-containing mortar

    DEFF Research Database (Denmark)

    Kappel, Annemette; Ottosen, Lisbeth M.; Kirkelund, Gunvor Marie;

    2015-01-01

    This paper reports an experimental study of aesthetical qualities of mortar containing sewage sludgeash (SSA). SSA is the residue produced at water treatment plants where incineration of the sludge is applied in order to decrease volume and to prevent pathogens from spreading. Today SSA is with a......This paper reports an experimental study of aesthetical qualities of mortar containing sewage sludgeash (SSA). SSA is the residue produced at water treatment plants where incineration of the sludge is applied in order to decrease volume and to prevent pathogens from spreading. Today SSA...... is with a few exceptions landfilled and thus, wasted.The purpose of the experiments was to examine the influence of SSA and how it affected the colour of mortar samples. SSA was ground in 6 different intervals and added to mortar mixes by replacing 20% of the cement. An additional focus was to examine...... the possibilities to accentuate the colours of the hardened mortar by using paper cuttings in the production of the samples. The result of the experiments showed that a colour scale can be developed from ground SSA, and that paper may have the potential of providing divers textural qualities when it is used...

  1. Use of rubble from building demolition in mortars.

    Science.gov (United States)

    Corinaldesi, V; Giuggiolini, M; Moriconi, G

    2002-01-01

    Because of increasing waste production and public concerns about the environment, it is desirable to recycle materials from building demolition. If suitably selected, ground, cleaned and sieved in appropriate industrial crushing plants, these materials can be profitably used in concrete. Nevertheless, the presence of masonry instead of concrete rubble is particularly detrimental to the mechanical performance and durability of recycled-aggregate concrete and the same negative effect is detectable when natural sand is replaced by fine recycled aggregate fraction. An alternative use of both masonry rubble and fine recycled material fraction could be in mortars. These could contain either recycled instead of natural sand or powder obtained by bricks crushing as partial cement substitution. In particular, attention is focused on the modification that takes place when either polypropylene or stainless steel fibers are added to these mortars. Polypropylene fibers are added in order to reduce shrinkage of mortars, stainless steel fibers for improving their flexural strength. The combined use of polypropylene fibers and fine recycled material from building demolition could allow the preparation of mortars showing good performance, in particular when coupled with bricks. Furthermore, the combined use of stainless steel fibers and mortars containing brick powder seems to be an effective way to guarantee a high flexural strength.

  2. Material Performance and Animal Clinical Studies on Performance-Optimized Hwangtoh Mixed Mortar and Concrete to Evaluate Their Mechanical Properties and Health Benefits

    Directory of Open Access Journals (Sweden)

    Bon-Min Koo

    2015-09-01

    Full Text Available In this study, the amount of cement used in a concrete mix is minimized to reduce the toxic effects on users by adjusting the concrete mixture contents. The reduction of cement is achieved by using various admixtures (ground granulated blast-furnace slag, flyash, ordinary Portland cement, and activated Hwangtoh powder. To apply the mix to construction, material property tests such as compressive strength, slump, and pH are performed. Preliminary experimental results showed that the Hwangtoh concrete could be used as a healthy construction material. Also, the health issues and effects of Hwangtoh mortar are quantitatively evaluated through an animal clinical test. Mice are placed in Hwangtoh mortar and cement mortar cages to record their activity. For the test, five cages are made with Hwangtoh and ordinary Portland cement mortar floors, using Hwangtoh powder replacement ratios of 20%, 40%, 60%, and 80% of the normal cement mortar mixing ratio, and two cages are made with Hwangtoh mortar living quarters. The activity parameter measurements included weight, food intake, water intake, residential space selection, breeding activity, and aggression. The study results can be used to evaluate the benefits of using Hwangtoh as a cement replacing admixture for lifestyle, health and sustainability.

  3. Use of a multi-species reactive transport model to simulate chloride ingress in mortar exposed to NaCl solution or sea-water

    DEFF Research Database (Denmark)

    Jensen, Mads Mønster; De Weerdt, K.; Johannesson, Björn;

    2015-01-01

    Simulations of ion ingress in Portland cement mortar using a multi-species reactive mass transport model are compared with experimental test results. The model is an extended version of the Poisson–Nernst–Planck equations, accounting for chemical equilibrium. Saturated mortar samples were exposed...

  4. Application of encapsulated lightweight aggregate impregnated with sodium monofluorophosphate as a self-healing agent in blast furnace slag mortar

    NARCIS (Netherlands)

    Sisomphon, K.; Copuroglu, O.; Fraaij, A.

    2011-01-01

    This paper studies the potential of using expanded clay lightweight aggregate impregnated with sodium monofluorophosphate (Na2FPO3) solution which is eventually encapsulated by a cement paste layer to produce a self-healing system in blast furnace slag cement mortars. It was found that the technique

  5. Link between microstructure and tritiated water diffusivity in mortars

    Directory of Open Access Journals (Sweden)

    Dangla P.

    2013-07-01

    Full Text Available Ions and radionuclide diffusivity in concrete is one of the most important factors that determine service life and safety assessment of cement based structures in nuclear power plants and radioactive-waste repositories. Apart from the influence of cement paste microstructure, the presence of aggregates may have an impact on transport properties of the material. The well-known interfacial transition zone, denoted by ITZ, is created near the aggregates and characterized by a greater porosity. The goal of this study is to investigate the competition between the more diffusing ITZ zone and the less diffusing aggregates. To this end, several series of tritiated water diffusion tests are conducted on mortars characterized by different water-to-cement ratios and sand volume fractions. In parallel, microstructure of these materials is explored by mercury and water porosimetry. It was observed that at low sand content (0% – 50%, diffusion properties of mortars are dominated by aggregates dilution effect. At 60% sand, diffusion increases significantly suggesting that percolation’s pores threshold has been reached. Results indicate also that sand particle size distribution has a great impact on the diffusivity of mortars.

  6. Link between microstructure and tritiated water diffusivity in mortars

    Science.gov (United States)

    Larbi, B.; Dridi, W.; Le Bescop, P.; Dangla, P.; Petit, L.

    2013-07-01

    Ions and radionuclide diffusivity in concrete is one of the most important factors that determine service life and safety assessment of cement based structures in nuclear power plants and radioactive-waste repositories. Apart from the influence of cement paste microstructure, the presence of aggregates may have an impact on transport properties of the material. The well-known interfacial transition zone, denoted by ITZ, is created near the aggregates and characterized by a greater porosity. The goal of this study is to investigate the competition between the more diffusing ITZ zone and the less diffusing aggregates. To this end, several series of tritiated water diffusion tests are conducted on mortars characterized by different water-to-cement ratios and sand volume fractions. In parallel, microstructure of these materials is explored by mercury and water porosimetry. It was observed that at low sand content (0% - 50%), diffusion properties of mortars are dominated by aggregates dilution effect. At 60% sand, diffusion increases significantly suggesting that percolation's pores threshold has been reached. Results indicate also that sand particle size distribution has a great impact on the diffusivity of mortars.

  7. Some masonary mortar from Hellenistic and Roman period Greece

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, H.H.G.

    1985-01-01

    The Mineral Resources Research Center at the University of Minnesota has been engaged for the past six years in projects to synthesize various hydraulic cements by plasma fusion. An analytical scheme was developed to examine the plasma products. The techniques used to examine these cements were applied to five masonary mortar samples of Hellenistic and Roman periods from three sites in Greece (Olympia, Larissa, and Trikkala). These were examined by chemical, microscopical (polarized light and scanning electron), x-ray diffraction, and differential thermal analysis methods. These samples are typical sand-lime mortars: The aggregates consist of quartz with small amounts of microcline or orthoclase and, in several of the samples, rock and chert fragments. The matrix is largely fine grained calcite and a small amount of calcium silicate hydrate, a typical phase found in hydraulic cements. The sample from the Altis in Olympia (160 to 170 A.D.) is a pink, dense mortar with medium to fine grained aggregate and shows excellent workmanship. This specimen contains reddish fragments which are probably pieces of ceramics which either are used as fill or are poorly crushed material added as a pozzolana. The samples were probably emplaced as a sand and slaked-lime mixture. The limes are impure and thus have feebly hydraulic properties.

  8. Modeling of properties of fiber reinforced cement composites

    Directory of Open Access Journals (Sweden)

    Jevtić Dragica

    2008-01-01

    Full Text Available This paper presents the results of authors' laboratory testing of the influence of steel fibers as fiber reinforcement on the change of properties of cement composite mortar and concrete type materials. Mixtures adopted - compositions of mortars had identical amounts of components: cement, sand and silica fume. The second type of mortar contained 60 kg/m3 of fiber reinforcement, as well as the addition of the latest generation of superplasticizer. Physical and mechanical properties of fiber reinforced mortars and etalon mixtures (density, flexural strength, compressive strength were compared. Tests on concrete type cement composites included: density, mechanical strengths and the deformation properties. The tests showed an improvement in the properties of fiber reinforced composites.

  9. SCIENTIFIC AND TECHNICAL PRECONDITIONS FOR EXTRUDED LIGHTWEIGHT CEMENT SYSTEMS

    Directory of Open Access Journals (Sweden)

    Oreshkin Dmitriy Vladimirovich

    2012-10-01

    The paper also presents the results of the research of the microstructure of spilt Portland cement and hollow glass spheres, their mineral and chemical analyses, as well as the properties of masonry mortars. The paper presents a conclusion that their high process-dependent parameters and superior operating performance are attainable through the introduction of effective hollow glass spheres into masonry mortars and the application of the extrusion method. The aforementioned novelties may reduce the water consumption rate, improve the strength, freeze resistance and durability of cement mortars. The preparation of this paper involved the study of nine reference books. This paper is the first one of a series of papers covering the method of extrusion of lightweight cement mortars.

  10. Effect of Nano-Alumina on Pore Structure and Durability of Class F Fly Ash Self-Compacting Mortar

    OpenAIRE

    E. Mohseni; Tsavdaridis, KD

    2016-01-01

    In this study the effect of pore structure on the mechanical properties and durability characteristics of Self-Compacting Mortars (SCM) containing nano-Al2O3 (NA) and class F fly ash are investigated. Al2O3 nanoparticles with the maximum size of 15 nm in three different proportions of 1, 3 and 5% of the binder content were utilized to partially replace the cement. The 25% of the cement weight was also replaced by class F fly ash. The pore structure of cement mortars was determined through the...

  11. 2nd Historic Mortars Conference

    CERN Document Server

    Hughes, John; Groot, Caspar; Historic Mortars : Characterisation, Assessment and Repair

    2012-01-01

    This volume focuses on research and practical issues connected with mortars on historic structures. The book is divided into four sections: Characterisation of Historic Mortars, Repair Mortars and Design Issues, Experimental Research into Properties of Repair Mortars, and Assessment and Testing. The papers present the latest work of researchers in their field. The individual contributions were selected from the contributions to the 2nd Historic Mortars Conference, which took place in Prague, September, 22-24, 2010. All papers were reviewed and improved as necessary before publication. This peer review process by the editors resulted in the 34 individual contributions included in here. One extra paper reviewing and summarising State-of-the-Art knowledge covered by this publication was added as a starting and navigational point for the reader. The editors believe that having these papers in print is important and they hope that it will stimulate further research into historic mortars and related subjects. 

  12. Compressive strength and heavy metal leaching behaviour of mortars containing spent catalyst.

    Science.gov (United States)

    Rattanasak, U; Jaturapitakkul, C; Sudaprasert, T

    2001-10-01

    This investigation was set and aimed to study the possibility of using spent catalyst as a concrete constituent which the spent catalyst was used as sand. Besides the spent catalyst was used as sand, it was also ground to very small particle size as small as that of cement and used as 20% replacement of cement by weight. Compressive strengths and leaching characteristics of lead, chromium, cadmium, and nickel in mortars containing spent catalyst and ground spent catalyst were tested. The results presented revealed that the compressive strength of mortar containing spent catalyst increased with ages. The results also indicated that the compressive strength of mortar containing spent catalyst at the proportion of 1.25 times of cement by weight was strong enough to make a concrete brick. In case of the ground spent catalyst being used to replace cement, it made the compressive strength lower than that of the standard mortar approximately 20%. The leachate results of lead and chromium from spent catalyst were lower than the allowance, but cadmium and nickel exceeded the limits. After the spent catalyst was fixed with cement, the leaching of the heavy metals did not exceed the industrial effluent standard. Therefore, the heavy metals mentioned earlier were not a problem in using spent catalyst as a concrete constituent.

  13. The adherence in the union stone-mortar

    Directory of Open Access Journals (Sweden)

    Rodríguez García, María Reyes

    1994-06-01

    Full Text Available Stones placates present a wide of problems that result in the fall of plates. One of the causes is the lack of adherence stone-mortar. We considered a study to determine the adherence between several cement mortars (1:3, 1:5, 1:7, 1:9 and a especial mortar prepared with latex and stones (white granite, pink granites, black granites, white marble and cream limestones. The results obtained suggest that only adequate adherence rates (higher than 3 kgf/cm2 achieved with cement mortar 1:3 and especial mortar. Besides it is observed that in the stones studied there is no relation between adherence and the absorption values.

    Los aplacados de piedra presentan una extensa patología que se traduce en la caída de las placas colocadas. Una de las causas es la falta de adherencia mortero-piedra. El estudio se realiza para determinar la tensión de adherencia entre diversos morteros de cemento (1:3, 1:5, 1:7, 1:9 y otro compuesto por mortero y látex y piedras (granito blanco, granitos rosa, granitos negros, mármol blanco y calizas crema. De los resultados obtenidos se deduce que los únicos morteros que permiten valores de adherencia aceptables (superiores a 3 kp/cm2 son el mortero de cemento 1:3 y el especial. Igualmente se comprueba que, en las piedras estudiadas, no existe relación alguna entre la adherencia y la absorción de agua.

  14. Transport Properties of Carbon-Nanotube/Cement Composites

    NARCIS (Netherlands)

    Han, B.; Yang, Z.; Shi, X.; Yu, X.

    2012-01-01

    This paper preliminarily investigates the general transport properties (i.e., water sorptivity, water permeability, and gas permeability) of carbon-nanotube/cement composites. Carboxyl multi-walled carbon nanotubes (MWNTs) are dispersed into cement mortar to fabricate the carbon nanotubes (CNTs) rei

  15. The Polymer Modified Mortar Used for Exterior Insulation%外墙外保温专用聚合物改性砂浆的研究

    Institute of Scientific and Technical Information of China (English)

    王治; 胡浩然

    2013-01-01

    研究了水泥、可再分散乳胶粉、纤维素醚等因素对抹面砂浆抗裂性能和粘结砂浆粘结性能的影响,并进行了分析,得出了抹面砂浆和粘结砂浆的最优配比。%The influences of cement,redispersable powder and cellulose ether on anti-cracking performance of anti-crack mortar and adhesive property of adhesive mortar were researched. Then the optimum proportion of anti-crack mortar and adhesive mortar was obtained.

  16. Mathematical Model Relating Uniaxial Compressive Behavior of Manufactured Sand Mortar to MIP-Derived Pore Structure Parameters

    OpenAIRE

    Tian, Zhenghong; Bu, Jingwu

    2014-01-01

    The uniaxial compression response of manufactured sand mortars proportioned using different water-cement ratio and sand-cement ratio is examined. Pore structure parameters such as porosity, threshold diameter, mean diameter, and total amounts of macropores, as well as shape and size of micropores are quantified by using mercury intrusion porosimetry (MIP) technique. Test results indicate that strains at peak stress and compressive strength decreased with the increasing sand-cement ratio due t...

  17. Análise fluido-dinâmica do escoamento em ensaio de permeabilidade ao ar de argamassas preparadas com cimento Portland de alto-forno Fluid-dynamic analysis of the flow in air permeability measurement of mortars prepared with blast-slag furnace Portland cement

    Directory of Open Access Journals (Sweden)

    V. M. Pereira

    2008-06-01

    . These studies not only have evaluated the permeability of porous media, but also to analyze the behavior of the fluid during the flow. Being about to the cement based materials, the measuring of the permeability becomes basic so that the durability of these can be estimate, therefore is the permeability that controls the rate of ingression and movement of deleterious agents inside these materials. Thus, diverse methodologies and mathematical equations have been used to foresee the permeability of cementitious materials, however, some discrepancies and nonsense in the results have been found. Amongst the used methodologies to measure the permeability of porous media, one meets developed it by Thenoz, which it has demonstrated good results in cement based materials. Thus, this work aims at, by means of assay of permeability to air, carried through in accordance with the methodology of Thenoz, to evaluate the fluid-dynamic behavior of air during the assay of permeability in mortars. For this, mortars prepared with two types of Portland cement of blast furnace (CP IIE-32 and CP III - 32, two relations water/cement (0.5 and 0.6 and ages of 14 and 28 days were used. By means of the gotten results it was possible to observe that during the draining the compressibility of air can be ignored, the regimen of draining can be considered as to plate, demonstrating that the methodology proposal for Thenoz and used mathematical equations can result in coefficients of trustworthy air permeability, therefore phenomena and considerations that could influence in this type of flow can be neglected, in accordance with what it is considered by literature.

  18. WATER QUALITY AND TREATMENT CONSIDERATIONS FOR CEMENT-LINED AND A-C PIPE

    Science.gov (United States)

    Both cement mortar lined (CML) and asbestos-cement pipes (A-C) are widely used in many water systems. Cement linings are also commonly applied in-situ after pipe cleaning, usually to prevent the recurrence of red water or tuberculation problems. Unfortunately, little consideratio...

  19. Correlation Between Initial Calcium Oxide Content of Slag Blended Cement and Mortar Leaching Mass Loss%矿渣混合水泥中初始氧化钙含量与砂浆溶蚀质量损失的关系

    Institute of Scientific and Technical Information of China (English)

    王培铭; 庞敏; 刘贤萍

    2016-01-01

    In the accelerated corrosion 142 d, the leaching mass loss behavior of Portland cement and slag blended cement of three different slag contents (50%, 70% and 90%, in mass fraction) mortar with two different pre-cured ages (28 and 180 d) was investigated. The initial CaO content, calcium hydroxide (CH) content and total hydration degree were analyzed. Based on the relation between CH content and initial CaO content in cement as well as mass loss, the correlation between the initial CaO content and mass loss, and the effect of total hydration degree on mass loss were studied. The results show that the mass loss of all the specimens of two different pre-cured age increase with the increase of leaching time (after 84 d increased slowly), decrease with the increase of addition of slag in blended cement. That is slag can improve the corrosion resistance performance, the fundamental cause of above improvement lies in slag reduced the CH content and hydration degree of blended cement paste. The mass loss with leaching time of 84 d and CH content (0 except) in cement paste, as well as the hydration degree (only slag blended cement) has the following linear relationship respectively. The former is y=0.207 5x–0.015 7, the latter is y=0.029 6x–0.125 4. The mass loss with leaching time of 84 d and initial CaO content in cement has a logarithmic relationship. Pre-cured 28 d, the regression equation is y=6.059ln(x)–22.164. Pre-cured 180 d, the regression equation is y=7.612 3ln(x)–27.656. Based on the logarithmic relationship, cement mortar corrosion resistance can be preliminary judged.%研究了2个预养护龄期(28和180 d)的硅酸盐水泥和3个矿渣粉掺量(50%、70%和90%)的混合水泥砂浆在加速溶蚀142 d 内的溶蚀质量损失规律,分析了硅酸盐水泥和混合水泥初始 CaO 含量、浆体中氢氧化钙(CH)含量和水化程度,基于浆体中 CH 含量与水泥初始 CaO 含量,以及溶蚀质量损失之间的

  20. Carbonation Characteristics of Alkali-Activated Blast-Furnace Slag Mortar

    Directory of Open Access Journals (Sweden)

    Keum-Il Song

    2014-01-01

    Full Text Available Alkali-activated ground granulated blast-slag (AAS is the most obvious alternative material for ordinary Portland cement (OPC. However, to use it as a structural material requires the assessment and verification of its durability. The most important factor for a durability evaluation is the degree of carbonation resistance, and AAS is known to show lower performance than OPC. A series of experiments was conducted with a view to investigate the carbonation characteristics of AAS binder. As a consequence, it was found that the major hydration product of AAS was calcium silicate hydrate (CSH, with almost no portlandite, unlike the products of OPC. After carbonation, the CSH of AAS turned into amorphous silica gel which was most likely why the compressive strength of AAS became weaker after carbonation. An increase of the activator dosage leads AAS to react more quickly and produce more CSH, increasing the compaction, compressive strength, and carbonation resistance of the microstructure.

  1. 《水泥砂浆和混凝土用天然火山灰质材料》JG/T315—2011解读%Interpretation of Natural Pozzolanic Materials Used for Cement Mortar and Concrete JG/T315—2011

    Institute of Scientific and Technical Information of China (English)

    周永祥; 王永海; 何更新; 王晶

    2012-01-01

    Compilation background and significance of Natural pozzolanic materials used for cement mortar and concrete JG/T315?011 are introduced. The main technique clauses of this code are explained. The scope,terms,definition, material composition and main technical indexes of natural pozzolanic materials are described in detail. Authors hope that the code issue can improve the development of natural pozzolanic materials.%介绍了《水泥砂浆和混凝土用天然火山灰质材料》JG/T315—2011的编制背景和意义.对标准的主要技术条款进行了解释和说明,详细阐述了天然火山灰质材料包括的范围、术语、定义,原材料组成,主要技术指标要求等.希望本标准的制定能为天然火山灰的开发利用起到积极促进作用.

  2. Improvements of nano-SiO2 on sludge/fly ash mortar.

    Science.gov (United States)

    Lin, D F; Lin, K L; Chang, W C; Luo, H L; Cai, M Q

    2008-01-01

    Sewage sludge ash has been widely applied to cementitious materials. In this study, in order to determine effects of nano-SiO(2) additives on properties of sludge/fly ash mortar, different amounts of nano-SiO(2) were added to sludge/fly ash mortar specimens to investigate their physical properties and micro-structures. A water-binding ratio of 0.7 was assigned to the mix. Substitution amounts of 0%, 10%, 20%, and 30% of sludge/fly ash (1:1 ratio) were proposed. Moreover, 0%, 1%, 2%, and 3% of nano-SiO(2) was added to the mix. Tests, including SEM and compressive strength, were carried out on mortar specimens cured at 3, 7, and 28 days. Results showed that sludge/fly ash can make the crystals of cement hydration product finer. Moreover, crystals increased after nano-SiO(2) was added. Hence, nano-SiO(2) can improve the effects of sludge/fly ash on the hydration of mortar. Further, due to the low pozzolanic reaction active index of sludge ash, early compressive strengths of sludge/fly ash mortar were decreased. Yet, nano-SiO(2) could help produce hydration crystals, which implies that the addition of nano-SiO(2) to mortar can improve the influence of sludge/fly ash on the development of the early strength of the mortar.

  3. Combined Effects of Non-Conforming Fly Ash and Recycled Masonry Aggregates on Mortar Properties

    Directory of Open Access Journals (Sweden)

    Ana Isabel Torres-Gómez

    2016-08-01

    Full Text Available This work evaluates the effects of using non-conforming fly ash (Nc-FA generated in a thermoelectric power plant as filler material for mortars made with natural sand (NA and recycled sand from masonry waste (FRMA. The incorporation of powdered recycled masonry filler (R-MF is also tested as an alternative to siliceous filler (Si-F. Three families of mortars were designed to study: the effect of replacing Si-F with Nc-FA on mortars made with NA; the effect of replacing Si-F with Nc-FA on mortars made with 50% of NA and 50% of FRMA; and the effect of replacing Si-F with R-MF on mortars made with NA and FRMA. Replacing Si-F with Nc-FA is a viable alternative that increases the mechanical strength, the workability and durability properties and decreases the shrinkage. The use of FRMA and Nc-FA improved the mechanical strength of mortars, and it slightly increased the shrinkage. The replacement of Si-F with R-MF on mortars made with FRMA is not a good alternative, because it has a negative impact on all of the properties tested. This work can help both to reduce cement and natural resources’ consumption and to increase the recycling rate of Nc-FA and FRMA.

  4. Compression Sensibility of Magnetic-concentrated Fly Ash Mortar under Uniaxial Loading

    Institute of Scientific and Technical Information of China (English)

    JIA Xingwen; ZHANG Yajie; QIAN Jueshi

    2012-01-01

    The electrical conductivity,compression sensibility,workability and cost are factors that affect the application of conductive smart materials in civil structures.Consequently,the resistance and compression sensibility of magnetic-concentrated fly ash (MCFA) mortar were investigated using two electrode method,and the difference of compression sensibility between MCFA mortar and carbon fiber reinforced cement (CFRC)under uniaxial loading was studied.Factors affecting the compression sensibility of MCFA mortar,such as MCFA content,loading rate and stress cycles,were analyzed.Results show that fly ash with high content of Fe3O4 can be used to prepare conductive mortar since Fe3O4 is a kind of nonstoichiometric oxide and usually acts as semiconductor.MCFA mortar exhibits the same electrical conductivity to that of CFRC when the content of MCFA is more than 40% by weight of sample.The compression sensibility of mortar is improved with the increase of MCFA content and loading rate.The compression sensibility of MCFA mortar is reversible with the circling of loading.Results show that the application of MCFA in concrete not only provides excellent performances of electrical-functionality and workability,but also reduces the cost of conductive concrete.

  5. FORMULATION OF EXPANSIVE MORTAR TO TILL THE STONES USING NON-METALLIC MINERALS OF NORTHEAST OF COUNTRY

    Directory of Open Access Journals (Sweden)

    Danielly Vieira de Lucena

    2015-03-01

    Full Text Available One of the most significant methods of advanced technology for mining, the rock massif is employing expansive mortar for cutting of Rock. Furthermore, the entire expansive mortar commercialized in the Brazilian domestic market are imported, as well as those in industrialized country. Both have components from the external market. The aim of this work is to develop expansive mortar with raw materials that have regional and pressure sufficient to remove the rocks of granite and marble type expansion. For this, expansive grout formulations using calcium oxide, calcium carbonate, carboxymethylcellulose are used - CMC (Portland cement, and from the chemical analysis by means of thermal analysis, X-ray diffraction and laser granulometry compared the results with a commercial mortar. The results indicated that the formulations showed characteristics similar to the commercial mortar.

  6. Effect of Mineral Admixtures on Resistance to Sulfuric Acid Solution of Mortars with Quaternary Binders

    Science.gov (United States)

    Makhloufi, Zoubir; Bederina, Madani; Bouhicha, Mohamed; Kadri, El-Hadj

    This research consists to study the synergistic action of three mineral additions simultaneously added to the cement. This synergistic effect has a positive effect on the sustainability of limestone mortars. Tests were performed on mortars based on crushed limestone sand and manufactured by five quaternary binders (ordinary Portland cement and CPO mixed simultaneously with filler limestone, blast-furnace and natural pozzolan). The purpose of this research was to identify the resistance of five different mortars to the solution of sulfuric acid. Changes in weight loss and compressive strength measured at 30, 60, 90, 120 and 180 days for each acid solution were studied. We followed up on the change in pH of the sulfuric acid solution at the end of each month up to 180 days.

  7. Greenlandic Waste Incineration Fly And Bottom Ash As Secondary Resource In Mortar

    DEFF Research Database (Denmark)

    Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.; Jensen, Pernille Erland;

    2016-01-01

    , the effects on compressive strengths of mortars by substituting cement or sand by raw, washed and electrodialytically treated fly ash or bottom ash were investigated. Parts of the experimental fly ash had been pre-treated by either washing with distilled water or electro-dialytically treated to remove salts...

  8. Microstructure development of a drying tile mortar containing methylhydroxy-ethylcellulose (MHEC)

    NARCIS (Netherlands)

    Faiyas, A.P.A.; Erich, S.J.F.; Nijland, T.G.; Hunnink, H.P.; Adan, O.C.G.

    2015-01-01

    Cement based mortars are widely used as adhesive for tiles in building and construction. They have a limited timespan during which a tile can be placed effectively in order to develop sufficient bond strength. This timespan, usually called ’open time’, is controlled, amongst others, by adding water

  9. Performance of Polymer Modified Mortar with Different Dosage of Polymeric Modifier

    Directory of Open Access Journals (Sweden)

    Ganesan Shankar

    2014-01-01

    Full Text Available Polymer modified mortar system is defined as hydraulic cement combined at the time of mixing with organic polymers that are dispersed or re-dispersed in water, with or without aggregates. The compressive strength and flexural strength of polymer modified mortar obtained at early age are low and it required prolong curing period for the strength enhancement. In order to enhance the mechanical properties of cementitious mixture as well as its durability, hybridization of polymeric modifiers are applied into cementitious mixture specimens. Thus, this study is intended to examine the mechanical properties of hybrid polymer modified mortar system at various levels of polymeric modifier dosage; styrene-butadiene rubber (SBR latex and epoxy resin. Laboratory tests for density, compressive strength and flexural strength were carried out to determine the strength of hybrid polymer modified mortar. In this study, the hybrid polymer of SBR latex with epoxy resin gives discontented results compared to unmodified cement system. The results of density, compressive strength and flexural strength of hybrid polymer modified cement system had shown negative outcomes and did not make any improvement to cement system.

  10. Electrochemical Behavior, Microstructural Analysis, and Morphological Observations in Reinforced Mortar Subjected to Chloride Ingress

    NARCIS (Netherlands)

    Koleva, D.A.; Van breugel, K.; De Wit, J.H.W.; Van Westing, E.; Boshkov, N.; Fraaij, A.L.A.

    2007-01-01

    The behavior of steel reinforcement was studied using electrochemical impedance spectroscopy (EIS) and polarization resistance (PR) techniques in conditions of chloride-induced corrosion in ordinary Portland cement-mortar specimens immersed in 7% NaCl for a test period of 120 days and compared to sp

  11. [Based on Curing Age of Calcined Coal Gangue Fine Aggregate Mortar of X-Ray Diffraction and Scanning Electron Microscopy Analysis].

    Science.gov (United States)

    Dong, Zuo-chao; Xia, Jun-wu; Duan, Xiao-mu; Cao, Ji-chang

    2016-03-01

    By using X-ray diffraction (XRD) and environmental scanning electron microscope (SEM) analysis method, we stud- ied the activity of coal gangue fine aggregate under different calcination temperature. In view of the activity of the highest-700 degrees C high temperature calcined coal gangue fine aggregate mortar of hydration products, microstructure and strength were discussed in this paper, and the change laws of mortar strength with curing age (3, 7, 14, 28, 60 and 90 d) growth were analyzed. Test results showed that coal gangue fine aggregate with the increase of calcination temperature, the active gradually increases. When the calcination temperature reaches 700 degrees C, the activity of coal gangue fine aggregate is the highest. When calcining temperature continues to rise, activity falls. After 700 degrees C high temperature calcined coal gangue fine aggregate has obvious ash activity, the active components of SiO2 and Al2 O3 can be with cement hydration products in a certain degree of secondary hydration reaction. Through on the top of the activity of different curing age 700 degrees C high temperature calcined coal gangue fine aggregate mortar, XRD and SEM analysis showed that with the increase of curing age, secondary hydration reaction will be more fully, and the amount of hydration products also gradually increases. Compared with the early ages of the cement mortar, the products are more stable hydration products filling in mortar microscopic pore, which can further improve the microstructure of mortar, strengthen the interface performance of the mortar. The mortar internal structure is more uniform, calcined coal gangue fine aggregate and cement mortar are more of a strong continuous whole, which increase the later strength of hardened cement mortar, 700 degrees C high temperature calcined coal gangue fine aggregate pozzolanic effect is obvious.

  12. Utilization of washed MSWI fly ash as partial cement substitute with the addition of dithiocarbamic chelate.

    Science.gov (United States)

    Gao, Xingbao; Wang, Wei; Ye, Tunmin; Wang, Feng; Lan, Yuxin

    2008-07-01

    The management of the big amount of fly ash as hazardous waste from the municipal solid waste incinerator (MSWI) has encountered many problems in China. In this study, a feasibility research on MSWI fly ash utilization as partial cement substitute in cement mortars was therefore carried out. MSWI fly ash was subjected to washing process to reduce its chlorine content (from 10.16% to 1.28%). Consequently, it was used in cement mortars. Ten percent and 20% replacement of cement by washed ash showed acceptable strength properties. In TCLP and 180-day monolithic tests, the mortars with washed ash presented a little stronger heavy metal leachability, but this fell to the blank level (mortar without washed ash) with the addition of 0.25% chelate. Therefore, this method is proposed as an environment-friendly technology to achieve a satisfactory solution for MSWI fly ash management.

  13. Compatibility of repair mortars in restoration projects

    OpenAIRE

    Schueremans, Luc; Van Balen, Koenraad; Cizer, Özlem; Janssens, Elke; Serré, Gerty; Elsen, Jan; Brosens, Kris; Ignoul, Sven

    2010-01-01

    Mortars used for restoration must be highly compatible with historic materials in terms of physical, chemical and mechanical properties in order to assure the durability of masonry on the long term. Compatibility criteria are defined based on the original mortar characteristics but the efficiency and the performance of the repair mortar after application on masonry are not generally evaluated. From this perspective, historic mortars and repair mortars from 3 historic masonry structures were a...

  14. Dry-grinded ultrafine cements hydration. physicochemical and microstructural characterization

    OpenAIRE

    Foteini Kontoleontos; Petros Tsakiridis; Apostolos Marinos; Nikolaos Katsiotis; Vasileios Kaloidas; Margarita Katsioti

    2013-01-01

    The aim of the present research work was the evaluation of the physicochemical and microstructural properties of two ultrafine cements, produced by dry grinding of a commercial CEM I 42.5N cement. The effect of grinding on particle size distribution was determined by laser scattering analyzer. All cements were tested for initial and final setting times, consistency of standard paste, soundness, flow of normal mortar and compressive strengths after 1, 2, 7 and 28 days. The effect of the finene...

  15. Mathematical model relating uniaxial compressive behavior of manufactured sand mortar to MIP-derived pore structure parameters.

    Science.gov (United States)

    Tian, Zhenghong; Bu, Jingwu

    2014-01-01

    The uniaxial compression response of manufactured sand mortars proportioned using different water-cement ratio and sand-cement ratio is examined. Pore structure parameters such as porosity, threshold diameter, mean diameter, and total amounts of macropores, as well as shape and size of micropores are quantified by using mercury intrusion porosimetry (MIP) technique. Test results indicate that strains at peak stress and compressive strength decreased with the increasing sand-cement ratio due to insufficient binders to wrap up entire sand. A compression stress-strain model of normal concrete extending to predict the stress-strain relationships of manufactured sand mortar is verified and agreed well with experimental data. Furthermore, the stress-strain model constant is found to be influenced by threshold diameter, mean diameter, shape, and size of micropores. A mathematical model relating stress-strain model constants to the relevant pore structure parameters of manufactured sand mortar is developed.

  16. Reuse of ash coal in the formulation of mortars; Reaproveitamento de cinzas de carvao mineral na formulacao de argamassas

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, J.S.; Souza, C.A.G.; Souza, J.A.S., E-mail: jacilene_s@yahoo.com.br, E-mail: celioag@ufpa.br, E-mail: jass@ufpa.br [Programa de Pos Graduacao em Engenharia Quimica, Universidade Federal do Para, UFPA/PPEQ, Belem, PA (Brazil)

    2012-04-15

    This paper aims to study the ash incorporation from the combustion of coal in fluidized bed boilers, in production of mortar, replacing part of cement. Specimens were prepared using Portland cement to the specifications CPII-E-32 of normal characteristics and classification of sand below 100 mesh. Blends in the 4:1 ratio, that is, 4 parts of aggregate to 1 part of cement, with insertion of ashes in the proportions 0, 10, 20, 30, 40 and 50%. The mortar was developed in mixing and casting was made in a mold of 5 cm x 10 cm. The behavior of compressive strength was evaluated after 28 days; the strength decreases with increasing percentage of ash. Additional analysis was carried out by X-ray diffraction, and it was found that the substitution of this waste can be successfully used in mortars with blends of up to 30%. (author)

  17. Mathematical Model Relating Uniaxial Compressive Behavior of Manufactured Sand Mortar to MIP-Derived Pore Structure Parameters

    Directory of Open Access Journals (Sweden)

    Zhenghong Tian

    2014-01-01

    Full Text Available The uniaxial compression response of manufactured sand mortars proportioned using different water-cement ratio and sand-cement ratio is examined. Pore structure parameters such as porosity, threshold diameter, mean diameter, and total amounts of macropores, as well as shape and size of micropores are quantified by using mercury intrusion porosimetry (MIP technique. Test results indicate that strains at peak stress and compressive strength decreased with the increasing sand-cement ratio due to insufficient binders to wrap up entire sand. A compression stress-strain model of normal concrete extending to predict the stress-strain relationships of manufactured sand mortar is verified and agreed well with experimental data. Furthermore, the stress-strain model constant is found to be influenced by threshold diameter, mean diameter, shape, and size of micropores. A mathematical model relating stress-strain model constants to the relevant pore structure parameters of manufactured sand mortar is developed.

  18. Mathematical model relating uniaxial compressive behavior of manufactured sand mortar to MIP-derived pore structure parameters.

    Science.gov (United States)

    Tian, Zhenghong; Bu, Jingwu

    2014-01-01

    The uniaxial compression response of manufactured sand mortars proportioned using different water-cement ratio and sand-cement ratio is examined. Pore structure parameters such as porosity, threshold diameter, mean diameter, and total amounts of macropores, as well as shape and size of micropores are quantified by using mercury intrusion porosimetry (MIP) technique. Test results indicate that strains at peak stress and compressive strength decreased with the increasing sand-cement ratio due to insufficient binders to wrap up entire sand. A compression stress-strain model of normal concrete extending to predict the stress-strain relationships of manufactured sand mortar is verified and agreed well with experimental data. Furthermore, the stress-strain model constant is found to be influenced by threshold diameter, mean diameter, shape, and size of micropores. A mathematical model relating stress-strain model constants to the relevant pore structure parameters of manufactured sand mortar is developed. PMID:25133257

  19. Inhibition of TROY promotes OPC differentiation and increases therapeutic efficacy of OPC graft for spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Sun Liang; Feng Xiaoling; Duan Yongshun; Zhang Yafang; Wu Shuliang; Liu Shengliang; Sun Qi; Li Zhuying; Xu Fengyan; Hou Chunmei; Harada Toshihide; Chu Ming; Xu Kun

    2015-01-01

    Objective:To observe the regulatory effects of TROY on neural myelination in central nervous system ( CNS ) and remyelination in response to spinal cord injury ( SCI ) by oligodendrocyte precursor cell ( OPC) . Results:TROY expression was detected by RT-PCR and Western blotting in OPCs as well as in differen-tiated premature and mature oligodendrocytes of postnatal mice. Pharmacological inhibition or RNAi-induced knockdown of TROY promotes OPC differentiation, whereas overexpression of TROY dampens oligodendrocyte mat-uration. Furthermore, treatment of co-cultures of DRG neurons and OPCs with TROY inhibitors promotes myelina-tion and myelin sheath-like structures. Mechanically, protein kinase C ( PKC) signaling is involved in the regula-tion of the inhibitory effects of TROY. Moreover, in situ transplantation of OPCs with TROY knockdown leads to notably enhanced remyelination as well as augmented recovery of motor function and nervous conduction in rats with SCI. Conclusions:Our results indicate that TROY negatively modulates remyelination in the CNS, and thus may be a suitable target for improving the therapeutic efficacy of cell transplantation for CNS injury.

  20. Effects of slag fineness on durability of mortars

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fine aggregate, reduce the consumption of the natural resources and improve the durability of concrete. In this study, the effect of the fineness on the high temperature and sulphate resistances of concrete mortar specimens, produced with ground granulated blast-furnace slag (GBFS)replacing cement, is investigated. The compressive and flexural strength test results for all series related to durability effects,exposing temperature and solutions, exposure times for these durability effects, slag content and fineness are discussed. Consequently, the optimum slag contents are determined for producing the sulphate and high temperature resistant mortars.

  1. Further investigations of the properties of polymer modified cements

    International Nuclear Information System (INIS)

    This report concludes the work done on behalf of the Department of the Environment on polymer modified cement composites. Topics covered include: the influence of cure schedule on flexural properties, observation of the onset and cracking during flexural testing, measurement of water permeability and caesium diffusion rates, and the use of Back Scattered Electron Imaging to identify the polymer phase. The properties of epoxide resin modified cements in the previous report were disappointing. Air entrainment of the mixing stage was a likely cause of the poor performance of these products and procedures to overcome this problem were devised. The range of polymer additives investigated was broadened by the inclusion of modified acrylic latexes and a polymensable acrylate resin additive. Properties for OPC and 9 BFS: 1 OPC cements are compared and the modification of properties achieved by polymer additions to both cement systems is discussed. (author)

  2. Production of cement requiring low energy expenditure. An industrial test

    Energy Technology Data Exchange (ETDEWEB)

    Gimenez, S.; Blanco, M.T.; Palomo, A.; Puertas, F. (Instituto de Ciencias de la Construccion, Madrid (Spain))

    1991-01-01

    A new method for making cement is proposed. It is based on the use of CaF{sub 2} and CaSO{sub 4} for partial replacement of the usual raw materials in cement manufacturing. This paper shows the feasibility of the proposed method on an industrial scale. A test carried out in a Spanish cement factory (1500 t yield of the new cement) has revealed that the mehtod can not only be adapted to the current technology but also requires a much lower energy expenditure. The final product is shown to have excellent properties in comparison with OPC. (orig.).

  3. 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.

  4. Influence of Cellulose Ethers on Hydration Products of Portland Cement

    Institute of Scientific and Technical Information of China (English)

    MA Baoguo; OU Zhihua; JIAN Shouwei; XU Rulin

    2011-01-01

    Cellulose ethers are widely used to mortar formulations, and it is significant to understand the interaction between cellulose ethers and cement pastes. FT-IR spectra, thermal analysis and SEM are used to investigate hydration products in the cement pastes modified by HEMC and HPMC in this article. The results show that the hydration products in modified cement pastes were finally identical with those in the unmodified cement paste, but the major hydration products, such as CH (calcium hydroxide), ettringite and C-S-H, appeared later in the modified cement pastes than in the unmodified cement paste. The cellulose ethers decrease the outer products and increase inner products of C-S-H gels. Compared to unmodified cement pastes, no new products are found in the modified cement pastes in the present experiment. The HEMC and HPMC investigation shows almost the same influence on the hydration products of Portland cement.

  5. Rheological and hydration characterization of calcium sulfoaluminate cement pastes

    OpenAIRE

    García-Maté, Marta; Santacruz, Isabel; de la Torre, Ángeles G.; León-Reina, Laura; Aranda, Miguel A. G.

    2012-01-01

    Calcium sulfoaluminate (CSA) cements are currently receiving a lot of attention because their manufacture produces less CO2 than ordinary Portland cement (OPC). However, it is essential to understand all parameters which may affect the hydration processes. This work deals with the study of the effect of several parameters, such as superplasticizer (SP), gypsum contents (10, 20 and 30 wt%) and w/c ratio (0.4 and 0.5), on the properties of CSA pastes during early hydration. This characteriza...

  6. Chemical functionalization of ceramic tile surfaces by silane coupling agents: polymer modified mortar adhesion mechanism implications

    Directory of Open Access Journals (Sweden)

    Alexandra Ancelmo Piscitelli Mansur

    2008-09-01

    Full Text Available Adhesion between tiles and mortars are crucial to the stability of ceramic tile systems. From the chemical point of view, weak forces such as van der Waals forces and hydrophilic interactions are expected to be developed preferably at the tiles and polymer modified Portland cement mortar interface. The main goal of this paper was to use organosilanes as primers to modify ceramic tile hydrophilic properties to improve adhesion between ceramic tiles and polymer modified mortars. Glass tile surfaces were treated with several silane derivatives bearing specific functionalities. Contact angle measurements and Fourier Transform Infrared Spectroscopy (FTIR were used for evaluating the chemical changes on the tile surface. In addition, pull-off tests were conducted to assess the effect on adhesion properties between tile and poly(ethylene-co-vinyl acetate, EVA, modified mortar. The bond strength results have clearly shown the improvement of adherence at the tile-polymer modified mortar interface, reflecting the overall balance of silane, cement and polymer interactions.

  7. 不同底模对砂浆强度的影响%Effect of Different Bottom Formwork on Strength of Mortar

    Institute of Scientific and Technical Information of China (English)

    孙永民; 胡长明; 宋方方

    2012-01-01

    The strength of cement mortar and mixed mortar with different bottom formwork were studied by tests. Results show that under the same consistency, the change of bottom mould has bigger influence on the strength of cement mortar than mixed mortar. Specifically, the discreteness of mortar strength with steel formwork is smaller than that with brick formwork. With the change of consistency, the cement mortar strength shows higher variation with steel formwork than with brick formwork. However for mixed mortar strength, the influence of consistency with steel formwork is smaller than that with brick formwork.%通过对不同底模的水泥砂浆试块和混合砂浆试块的强度试验研究,在相同稠度情况下,采用不同底模时,水泥砂浆强度比混合砂浆强度影响大.研究结果表明:钢底模比砖底模的离散性小;随着稠度变化,水泥砂浆采用钢底模比采用砖底模影响因素大,但混合砂浆采用钢底模比砖底模影响因素小.

  8. Modelling mirror aberrations in FEL oscillators using OPC

    NARCIS (Netherlands)

    Slot, van der P.J.M.; Karssenberg, J.G.; Boller, K.J.

    2007-01-01

    Several high power free-electron lasers (FELs) are currently under design, operational or being upgraded. One central issue is the beam outcoupling and mirror deformation due to absorbed power. Here we present an extension to the OPC code that allows it to model mirror distorions. We use this code t

  9. Active iron-rich belite sulfoaluminate cements: clinkering and hydration.

    Science.gov (United States)

    Cuberos, Antonio J M; De la Torre, Angeles G; Alvarez-Pinazo, G; Martín-Sedeño, M Carmen; Schollbach, Katrin; Pöllmann, Herbert; Aranda, Miguel A G

    2010-09-01

    Ordinary Portland cement (OPC) is an environmentally contentious material, as for every ton of OPC produced, on average, 0.97 tons of CO2 are released. Conversely, belite sulfoaluminate (BSA) cements are promising eco-friendly building materials, as their production may deplete CO2 emissions up to 35% (compared to OPC). However, the hydration rate of belite is slow. Here, we report the clinkering of iron-rich BSA materials, their activation with B2O3, and establishing a methodology to measure their improved reactivities. Nonactivated BSA clinker contained only beta belite phase, 52 wt %. Meanwhile, BSA clinkers activated with 1 and 2 wt % of B2O3 contained 28 wt % of beta and 25 wt % of alpha'H; and 54 wt % of alpha'H phase, respectively. Therefore, activation of BSA has been proved as alpha'H-belite is stabilized. The hydration of the cements has been studied by laboratory and synchrotron X-ray powder diffraction (using Rietveld method and chemical constraints), calorimetry, and environmental scanning electron microscopy. Cement pastes have different hydration rates. For nonactivated BSA cement, 20 and 48% of the belite reacted after one and three months, respectively. Conversely, 37-49% after one month and 52-62% after three months of overall belite reactivities have been measured for BSA cements activated with B2O3. PMID:20701316

  10. EFFECT OF NATURAL ZEOLITE ON THE COMPRESSIVE STRENGTH AND FREEZE-THAW RESISTANCE OF PORTLAND CEMENT

    OpenAIRE

    Bayartsetseg, E.; Lkhagvajargal, G.; Batgerel, D.; Sarangerel, D.; Ochirkhuyag, B

    2011-01-01

    Effects of zeolites in various natural deposits as replacement cementing material on mechanical performance of Portland cement were studied. The blended cement pastes with zeolites were cured at room temperature in air for various durations (1, 7 and 28 days). Mechanical performance of the blended cement samples such as setting time, volume of water, compressive strength, normal consistency and freeze-thaw resistance of the mortar are determined. The optimal substitution ratio was 20 wt. % of...

  11. Pozzolanic Activity Assessment of LUSI (LUmpur SIdoarjo Mud in Semi High Volume Pozzolanic Mortar

    Directory of Open Access Journals (Sweden)

    Danny Christianto

    2012-09-01

    Full Text Available LUSI mud obtained from the mud volcano in Sidoarjo, Indonesia, is a viable aluminosilicate material to be utilized as pozzolanic material. LUSI is an abbreviation of the local name of the mud, i.e., Lumpur Sidoarjo, meaning Sidoarjo mud. This paper reports the results of an investigation to assess the pozzolanic activity of LUSI mud, especially in semi high volume pozzolanic mortar. In this case, the amount of mud incorporated is between 30% to 40% of total cementitious material, by mass. The content of SiO2 in the mud is about 30%, whilst the total content of SiO2, Fe2O3 and Al2O3 is more than 70%. Particle size and degree of partial cement replacement by treated LUSI mud affect the compressive strength, the strength activity index (SAI, the rate of pozzolanic activity development, and the workability of mortar incorporating LUSI mud. Manufacturing semi high volume LUSI mud mortar, up to at least 40% cement replacement, is a possibility, especially with a smaller particle size of LUSI mud, less than 63 μm. The use of a larger percentage of cement replacement by LUSI mud does not show any adverse effect on the water demand, as the flow of the fresh mortar increased with the increase of percentage of LUSI mud usage.

  12. Scanner OPC signatures: automatic vendor-to-vendor OPE matching

    Science.gov (United States)

    Renwick, Stephen P.

    2009-03-01

    As 193nm lithography continues to be stretched and the k1 factor decreases, optical proximity correction (OPC) has become a vital part of the lithographer's tool kit. Unfortunately, as is now well known, the design variations of lithographic scanners from different vendors cause them to have slightly different optical-proximity effect (OPE) behavior, meaning that they print features through pitch in distinct ways. This in turn means that their response to OPC is not the same, and that an OPC solution designed for a scanner from Company 1 may or may not work properly on a scanner from Company 2. Since OPC is not inexpensive, that causes trouble for chipmakers using more than one brand of scanner. Clearly a scanner-matching procedure is needed to meet this challenge. Previously, automatic matching has only been reported for scanners of different tool generations from the same manufacturer. In contrast, scanners from different companies have been matched using expert tuning and adjustment techniques, frequently requiring laborious test exposures. Automatic matching between scanners from Company 1 and Company 2 has remained an unsettled problem. We have recently solved this problem and introduce a novel method to perform the automatic matching. The success in meeting this challenge required three enabling factors. First, we recognized the strongest drivers of OPE mismatch and are thereby able to reduce the information needed about a tool from another supplier to that information readily available from all modern scanners. Second, we developed a means of reliably identifying the scanners' optical signatures, minimizing dependence on process parameters that can cloud the issue. Third, we carefully employed standard statistical techniques, checking for robustness of the algorithms used and maximizing efficiency. The result is an automatic software system that can predict an OPC matching solution for scanners from different suppliers without requiring expert intervention.

  13. Preparation and mechanical properties of graphene oxide: cement nanocomposites.

    Science.gov (United States)

    Babak, Fakhim; Abolfazl, Hassani; Alimorad, Rashidi; Parviz, Ghodousi

    2014-01-01

    We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1-2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM) used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H) gels in GO cement mortar compared with the normal cement mortar.

  14. Preparation and Mechanical Properties of Graphene Oxide: Cement Nanocomposites

    Directory of Open Access Journals (Sweden)

    Fakhim Babak

    2014-01-01

    Full Text Available We investigate the performance of graphene oxide (GO in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1–2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H gels in GO cement mortar compared with the normal cement mortar.

  15. Influence of the calcium sulfate source on the rheological behaviour of calcium sulfoaluminate cement pastes

    OpenAIRE

    Santacruz, Isabel; García-Maté, Marta; G. Aranda, Miguel Ángel; De la Torre, Ángeles G.

    2013-01-01

    Calcium sulfoaluminate (CSA) cements are receiving increasing attention since their manufacture produces much less CO2 than ordinary Portland cement (OPC) [1]. In addition, they show interesting properties such as high early-age strengths, short setting times and impermeability. The main uses of these CSA cements are for quick repairs and pre-cast products or floor concrete applications. They are prepared by mixing the clinker with different amounts of a calcium sulfate set regulator such as ...

  16. PROPERTIES OF LIGHTWEIGHT MASONRY MORTARS WITH HOLLOW GLASS MICROSPHERES FOR WINTER CONDITIONS

    Directory of Open Access Journals (Sweden)

    Semenov Vyacheslav Sergeevich

    2012-10-01

    reduction fillers (such as inflated pearlite, vermiculite etc. demonstrate low strength properties, as such fillers have a high water content. Hollow glass (or ceramic microspheres are known as efficient fillers for lightweight mortars. Multiple research undertakings contain information on the masonry mortar that has the following properties: average density of dry mortar - 450 kg/m3, thermal conductivity factor - 0.17 W/(m·°C, compressive strength at the age of 28 days - 3.2 MPa, water retention rate - over 90 %. The climatic conditions of Russia determine the need to perform masonry works at negative temperatures. Adding antifreeze admixtures is an easy and cheap method that guarantees hydration of the Portland-cement at negative temperatures. The subject of this research covers masonry mortars that have a 15 % hollow glass microsphere content and antifreeze admixtures. Contemporary antifreeze admixtures are multifunctional. Therefore, traditional antifreeze admixtures such as sodium chloride, calcium chloride, sodium nitrite, sodium nitrate, sodium formate, potash were used in the research. The per-cent content of antifreeze admixtures was calculated. The following properties of masonry mortars with a 15 % content of hollow glass microspheres and antifreeze admixtures were identified: average mortar and mortar mixture density, setting time, water retention, compressive and bending strength, and water absorption. Standard research methods were employed. Every mortar has an 8 cm mobility. The benchmark mixture has an average density of 1.085 kg/ m3, average cement stone density of 980 kg/m3, compressive strength at the age of 28 days - 19.8 MPa, water retention rate - 97 %, setting time - 4.5 hours. The attention was driven to the strength analysis of mortars with hollow glass microspheres and antifreeze admixtures at positive and negative temperatures. The authors proved that antifreeze admixtures demonstrated a negative influence on the strength and setting

  17. Energy absorption at high strain rate of glass fiber reinforced mortars

    Directory of Open Access Journals (Sweden)

    Fenu Luigi

    2015-01-01

    Full Text Available In this paper, the dynamic behaviour of cement mortars reinforced with glass fibers was studied. The influence of the addition of glass fibers on energy absorption and tensile strength at high strain-rate was investigated. Static tests in compression, in tension and in bending were first performed. Dynamic tests by means of a Modified Hopkinson Bar were then carried out in order to investigate how glass fibers affected energy absorption and tensile strength at high strain-rate of the fiber reinforced mortar. The Dynamic Increase Factor (DIF was finally evaluated.

  18. Energy absorption at high strain rate of glass fiber reinforced mortars

    Science.gov (United States)

    Fenu, Luigi; Forni, Daniele; Cadoni, Ezio

    2015-09-01

    In this paper, the dynamic behaviour of cement mortars reinforced with glass fibers was studied. The influence of the addition of glass fibers on energy absorption and tensile strength at high strain-rate was investigated. Static tests in compression, in tension and in bending were first performed. Dynamic tests by means of a Modified Hopkinson Bar were then carried out in order to investigate how glass fibers affected energy absorption and tensile strength at high strain-rate of the fiber reinforced mortar. The Dynamic Increase Factor (DIF) was finally evaluated.

  19. Effect of Slag Content on the Strength of Mortar and Concrete%矿渣掺量对胶砂和混凝土强度的影响

    Institute of Scientific and Technical Information of China (English)

    周万良; 方坤河

    2012-01-01

    In this paper,the effects of the content of slag on the strength of mortar and concrete and the bond strength between concrete and steel bar were studied. With the increase of substituted amount of cement by slag in cement mortar or in fly ash-cement mortar, 3 d strength of the mortar continuously decreased. If substituted amount of cement by slag was less than 55% in cement mortar or in fly ash-cement mortar,the 28 d strength of the mortar would increase;if substituted amount of cement was more than 60% , the strength of the mortar would decrease. Whether in cement concrete or in fly ash-cement concrete, the compressive strength and bond strength would increase if the substituted amount of cement by slag was less than 50% ;they would decrease if the substituted amount of cement was higher than 60%.%本文研究了矿渣掺量对胶砂强度、混凝土强度和混凝土与钢筋的粘结强度的影响.在水泥胶砂或粉煤灰-水泥胶砂中,用矿渣取代部分水泥后,胶砂3d强度会降低,且随取代量增加,胶砂3d强度逐渐降低.在水泥胶砂或粉煤灰-水泥胶砂中,当矿渣取代水泥量≤55%时胶砂28 d强度会增加,但矿渣取代水泥量至60%时胶砂28 d强度会下降.在水泥混凝土或粉煤灰-水泥混凝土中,当矿渣取代水泥量≦50%时混凝土28 d强度及其与钢筋的粘结强度会提高,但矿渣取代水泥量≥60%时混凝士强度和粘结强度会降低.

  20. Cement pastes alteration by liquid manure organic acids: chemical and mineralogical characterization

    International Nuclear Information System (INIS)

    Liquid manure, stored in silos often made of concrete, contains volatile fatty acids (VFAs) that are chemically very aggressive for the cementitious matrix. Among common cements, blast-furnace slag cements are classically resistant to aggressive environments and particularly to acidic media. However, some standards impose the use of low C3A content cements when constructing the liquid manure silos. Previous studies showed the poor performance of low-C3A ordinary Portland cement (OPC). This article aims at clarifying this ambiguity by analyzing mechanisms of organic acid attack on cementitious materials and identifying the cement composition parameters influencing the durability of agricultural concrete. This study concentrated on three types of hardened cement pastes made with OPC, low-C3A OPC and slag cement, which were immersed in a mixture of several organic acids simulating liquid manure. The chemical and mineralogical modifications were analyzed by electronic microprobe, XRD and BSE mode SEM observations. The attack by the organic acids on liquid manure may be compared with that of strong acids. The alteration translates into a lixiviation, and the organic acid anions have no specific effect since the calcium salts produced are soluble in water. The results show the better durability of slag cement paste and the necessity to limit the amount of CaO, to increase the amount of SiO2 (i.e., reduction of the Ca/Si ratio of C-S-H is not sufficient) and to favor the presence of secondary elements in cement

  1. The characterisation, improvement and modelling aspects of Frost Salt Scaling of Cement-Based Materials with a High Slag Content

    NARCIS (Netherlands)

    Copuroglu, O.

    2006-01-01

    Blast furnace slag cement concrete is used extensively in a number of countries. In comparison with OPC, it is particularly well known for its excellent performance in marine environments. One dis-advantage of slag cement is its vulnerability to scaling under the combined load of freezing-thawing an

  2. 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.

  3. Properties of Fiber-Reinforced Mortars Incorporating Nano-Silica

    Directory of Open Access Journals (Sweden)

    Ahmed Ghazy

    2016-02-01

    Full Text Available Repair and rehabilitation of deteriorating concrete elements are of significant concern in many infrastructural facilities and remain a challenging task. Concerted research efforts are needed to develop repair materials that are sustainable, durable, and cost-effective. Research data show that fiber-reinforced mortars/concretes have superior performance in terms of volume stability and toughness. In addition, it has been recently reported that nano-silica particles can generally improve the mechanical and durability properties of cement-based systems. Thus, there has been a growing interest in the use of nano-modified fiber-reinforced cementitious composites/mortars (NFRM in repair and rehabilitation applications of concrete structures. The current study investigates various mechanical and durability properties of nano-modified mortar containing different types of fibers (steel, basalt, and hybrid (basalt and polypropylene, in terms of compressive and flexural strengths, toughness, drying shrinkage, penetrability, and resistance to salt-frost scaling. The results highlight the overall effectiveness of the NFRM owing to the synergistic effects of nano-silica and fibers.

  4. Experimental Study of the Possibility to Make a Mortar with Ternary Sand (Natural and Artificial Fine Aggregates)

    Science.gov (United States)

    Baali, L.; Naceri, A.; Rahmouni, Z.; Mehidi, M. W. Noui

    This experimental study investigates the possibility to make a mortar with a ternary sand (natural and artificial fine aggregates). This method is utilized to correct the particle size distribution of various sands used in mortar. For this investigation, three sands have been used: a dune sand (DS), a slag sand (SS), and brick sand (BS) at different proportions in mortar. After crushing, the artificial fine aggregate (blast furnace slag and waste brick fine aggregate) was sifted in order to use it as fine aggregate. The effect of the quality and grain size distribution of natural fine aggregate (i.e., DS) and artificial fine aggregates (i.e., SS and BS) on the physical properties of ternary sand confected (density, porosity, fineness modulus, equivalent sand, particle size distribution, water absorption) and properties of fresh and hardened mortar were analysed. In the same way for this study, the physical properties and chemical compositions of DS, SS, BS and cement were investigated. The results obtained show that the mechanical strength on mortar depends of the nature and particle size distribution of sand studied. The reuse of this recycled material (slag blast furnace and waste brick) in the industry would contribute to the protection of the environment. This study shows the potential of this method to make mortar with ternary sand (natural and artificial fine aggreagates) in order to improve the physical properties of sand. Utilising natural and artificial fine aggregates to produce quality mortar should yield significant environmental benefits.

  5. Tracing formation and durability of calcite in a Punic-Roman cistern mortar (Pantelleria Island, Italy).

    Science.gov (United States)

    Dietzel, Martin; Schön, Frerich; Heinrichs, Jens; Deditius, Artur P; Leis, Albrecht

    2016-01-01

    Ancient hydraulic lime mortar preserves chemical and isotopic signatures that provide important information about historical processing and its durability. The distribution and isotopic composition of calcite in a mortar of a well-preserved Punic-Roman cistern at Pantelleria Island (Italy) was used to trace the formation conditions, durability, and individual processing periods of the cistern mortar. The analyses of stable carbon and oxygen isotopes of calcite revealed four individual horizons, D, E, B-1 and B-2, of mortar from the top to the bottom of the cistern floor. Volcanic and ceramic aggregates were used for the production of the mortar of horizons E/D and B-1/B-2, respectively. All horizons comprise hydraulic lime mortar characterized by a mean cementation index of 1.5 ± 1, and a constant binder to aggregate ratio of 0.31 ± 0.01. This suggests standardized and highly effective processing of the cistern. The high durability of calcite formed during carbonation of slaked lime within the matrix of the ancient mortar, and thus the excellent resistance of the hydraulic lime mortar against water, was documented by (i) a distinct positive correlation of δ(18)Ocalcite and δ(13)Ccalcite; typical for carbonation through a mortar horizon, (ii) a characteristic evolution of δ(18)Ocalcite and δ(13)Ccalcite through each of the four mortar horizons; lighter follow heavier isotopic values from upper to lower part of the cistern floor, and (iii) δ(18)Ocalcite varying from -10 to -5 ‰ Vienna Pee Dee belemnite (VPDB). The range of δ(18)Ocalcite values rule out recrystallization and/or neoformation of calcite through chemical attack of water stored in cistern. The combined studies of the chemical composition of the binder and the isotopic composition of the calcite in an ancient mortar provide powerful tools for elucidating the ancient techniques and processing periods. This approach helps to evaluate the durability of primary calcite and demonstrates the

  6. Incorporation of titanium dioxide nanoparticles in mortars - Influence of microstructure in the hardened state properties and photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, S.S., E-mail: sandra.lucas@ua.pt [University of Aveiro/CICECO, Department of Civil Engineering, 3810-193 Aveiro (Portugal); Ferreira, V.M., E-mail: victorf@ua.pt [University of Aveiro/CICECO, Department of Civil Engineering, 3810-193 Aveiro (Portugal); Barroso de Aguiar, J.L., E-mail: aguiar@civil.uminho.pt [University of Minho, Department of Civil Engineering, Campus de Azurem, 4800-058 Guimaraes (Portugal)

    2013-01-15

    The environmental pollution in urban areas is one of the causes for poor indoor air quality in buildings, particularly in suburban areas. The development of photocatalytic construction materials can contribute to clean the air and improve sustainability levels. Previous studies have focused mainly in cement and concrete materials, disregarding the potential application in historic buildings. In this work, a photocatalytic additive (titanium dioxide) was added to mortars prepared with aerial lime, cement and gypsum binders. The main goal was to study the way that microstructural changes affect the photocatalytic efficiency. The photocatalytic activity was determined using a reactor developed to assess the degradation rate with a common urban pollutant, NO{sub x}. The laboratory results show that all the compositions tested exhibited high photocatalytic efficiency. It was demonstrated that photocatalytic mortars can be applied in new and old buildings, because the nanoadditives do not compromise the mortar hardened state properties.

  7. Dry ripened mortar with quarry waste and rubber powder from unserviceable tires

    Directory of Open Access Journals (Sweden)

    José Aparecido Canova

    2015-01-01

    Full Text Available Stone-quarry fines have been evaluated in mortar and concrete, but have presented drying shrinkage and consequently higher incidence of cracks than those with natural sand. This study compared the dry ripened mortar in two types of aggregates added of 8% rubber powder. It was used quicklime, artificial and natural sand in volumetric proportions of 1:6. Mixtures were oven-dried, received the cement, establishing the volumetric proportion of 1: 1.5:9. Inplastic state, we evaluated aspects such as consistence, air content, water retention and bleeding; whereas compressive strength, static deformation modulus and water absorption by capillarity was determined in hardened state. Cracking aspects were evaluated in substrate. As a result, the mortar with artificial sand showed higher increases in compressive strength, capillarity rate and cracking, and greater reductions in air content and bleeding. As for the rubber powder, exhibited a greater reduction in the cracking rate and capillarity was found.

  8. Preparation and Characterization of New Geopolymer-Epoxy Resin Hybrid Mortars

    Directory of Open Access Journals (Sweden)

    Raffaele Cioffi

    2013-07-01

    Full Text Available The preparation and characterization of metakaolin-based geopolymer mortars containing an organic epoxy resin are presented here for the first time. The specimens have been prepared by means of an innovative in situ co-reticulation process, in mild conditions, of commercial epoxy based organic resins and geopolymeric slurry. In this way, geopolymer based hybrid mortars characterized by a different content of normalized sand (up to 66% in weight and by a homogeneous dispersion of the organic resin have been obtained. Once hardened, these new materials show improved compressive strength and toughness in respect to both the neat geopolymer and the hybrid pastes since the organic polymer provides a more cohesive microstructure, with a reduced amount of microcracks. The microstructural characterization allows to point out the presence of an Interfacial Transition Zone similar to that observed in cement based mortars and concretes. A correlation between microstructural features and mechanical properties has been studied too.

  9. Influence of particle packing density on the rheology of low cement content concrete

    NARCIS (Netherlands)

    Fennis-Huijben, S.A.A.M.; Grunewald, S.; Walraven, J.C.; Den Uijl, J.A.

    2012-01-01

    Optimizing concrete mixtures with regard to cement content is one of the most important solutions in sustainable concrete design. Workability o f these low cement content or ecological mixtures is very important. Eleven mortar mixtures are presented, which show how a higher packing density can be us

  10. Immobilization of radioactive waste in cement-based matrices

    International Nuclear Information System (INIS)

    A solubility model of the system CaO-SiO2-H2O is developed which takes account of the state of Si polymerization in the solid. Free energies of formations of its bonding hydrogel are tabulated. The internal redox conditions in cements have been measured; in particular, slags lower the Esub(eta) relative to OPC. The fate of Sr and U in cement systems has been determined; Sr is incorporated in the aluminate phases, while U6+ is precipitated as Ca-U-O-H2O phases. Lowering the internal Esub(eta) reduces U solubility. Studies of the carbonation of slag-cement blends are reported. (author)

  11. Influence of Bed Ash and Fly Ash Replacement in Mortars

    Directory of Open Access Journals (Sweden)

    S. L. Summoogum-Utchanah

    2015-03-01

    Full Text Available The study evaluates the influence of fly ash and bottom ash as partial cement substitutes in mortars by studying the particle size distribution, consistency, flow, fresh density, air content, compressive strength and flexural strength characteristics. The results revealed that fly ash and cement had relatively the same particle size distribution unlike bottom ash. In the fresh state, as the amount of pozzolans increased in the mixtures, the mortars showed an enhancement in workability, were susceptible to water loss by bleeding, and exhibited a decline in fresh density. The early strength gains of the fly ash samples were low but reached higher than the control after 28 days of curing. The flexural strength increased as the fly ash content rose to reach a maximum at 20 % replacement. However, the 2-day compressive strength of bottom ash samples was higher than the control but decreased after 28 days of curing while the flexural strength declined with addition of bottom ash except at 5 % substitution.

  12. Immobilization of radioactive waste in cement-based matrices

    International Nuclear Information System (INIS)

    Model studies of the behaviour of cement systems have been advanced by considering the nature of the phases formed during hydration and deriving pH-composition models for the CaO-SiO2-H2O system. Preliminary results of Esub(h) measurements are also reported. Leach tests on Sr from cements are interpreted in terms of Sr retention mechanisms. Present results indicate that the aluminate phases in OPC contribute to the chemical retentivity. Studies on cement-clinoptilolite reactions, made using coarse grained clinoptilolite are reported: ferrierite also reacts chemically with cement. Two critical surveys are presented, together with new data: one on the potential of blended cements, the other on cement durability in CO2-containing environments. (author)

  13. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar.

    Science.gov (United States)

    Jackson, Marie D; Landis, Eric N; Brune, Philip F; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans-Rudolf; Monteiro, Paulo J M; Ingraffea, Anthony R

    2014-12-30

    The pyroclastic aggregate concrete of Trajan's Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime-volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium-aluminum-silicate-hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8-0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥ 90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900-y-old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45-0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale.

  14. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

    Science.gov (United States)

    Landis, Eric N.; Brune, Philip F.; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans-Rudolf; Monteiro, Paulo J. M.; Ingraffea, Anthony R.

    2014-01-01

    The pyroclastic aggregate concrete of Trajan’s Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime–volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium–aluminum-silicate–hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8–0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900-y-old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45–0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale. PMID:25512521

  15. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar.

    Science.gov (United States)

    Jackson, Marie D; Landis, Eric N; Brune, Philip F; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans-Rudolf; Monteiro, Paulo J M; Ingraffea, Anthony R

    2014-12-30

    The pyroclastic aggregate concrete of Trajan's Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime-volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium-aluminum-silicate-hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8-0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥ 90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900-y-old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45-0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale. PMID:25512521

  16. Language Select Language Article Tools Print this article Indexing metadata How to cite item Email this article Email the author Information For Authors For Librarians p-ISSN: 2088-4842 e-ISSN: 2442-8795 Home > Vol 15, No 1 > Putri Penjadwalan Cement Mill Berbasis Minimasi Faktor Klinker dalam Proses Pembilasan dan Impor Klinker

    Directory of Open Access Journals (Sweden)

    Nilda Tri Putri

    2016-04-01

    Full Text Available PT Semen Padang is one of the cement companies in indonesia. Cement production influenced by the number of demand, raw materials and the number of available machine. The number of demand increases with a corporate capacity which keep the company had to set an optimal production schedule. Scheduling production should be followed by the availability of raw materials (clinker. The number of clinker required influenced by the number of demands and clinker elapsed to the flushing process. Flushing process happen if the transition products produced from Non OPC to a product OPC, for one flushing process causes clinker consumption 7% more that the existing capacity decreases. Deficient in capacity covered by importing clinker which causes high cost production. So, it necessary to make cement mill schedule by minimize flushing process, so clinker that will be used become optimized. Steps that will be done in this study began with the survey system, identify problems, and data collection. Data collected are machine cement mill and kiln capacity, demands, and flushing process. Then designed a formulation model that is minimize clinker factor and the number of clinker imports needed, so that obtained scheduling machine cement mill to produce OPC and Non OPC. Results obtained by reducing the number of flushing process because the cement mill designed to producing one type of product per day, so the flushing process could happen if there is transition cement production Non OPC on the day-i to cement OPC on the day i+1. Cement OPC produced by indarung II, III, and V. Indarung IV only produced cement Non OPC, so the flushing process happened in Indarung II, III, and V.

  17. Cross-contamination in Porcelain Mortars.

    Science.gov (United States)

    Bauer-Brandl, A; Falck, A; Ingebrigtsen, L; Nilson, C

    2001-01-01

    Porcelain mortars and pestles are frequently used to comminute drug substances on a small scale and (in some cases) in the production of liquid and semisolid suspensions. Although it is generally accepted that removal of a drug substance from a rough surface by rinsing may be difficult and may lead to cross-contamination, no hard data support that theory. In this study, the amount of salicylic acid remaining on a porcelain mortar after different washing procedures was quantified and compared with the amount remaining on a plastic mortar. Drug residues in the "mg" range on the porcelain mortars made common rinsing procedures appear inappropriate, but no traces of drug were detected on plastic mortars. In addition, the quality of suspension ointments with respect to particle size and homogeneity produced by the two types of mortars was compared. Porcelain and plastic mortars appeared equally suitable for use in the production of semisolid suspensions.

  18. The effect of temperature rise on microstructural properties of cement-based materials: correlation of experimental data and a simulation approach

    NARCIS (Netherlands)

    Susanto, A.; Koleva, D.A.; Van Breugel, K.

    2015-01-01

    This work reports on the influence of stray current flow on temperature rise in hardening cement-based materials and consequently altered cement hydration. To simulate stray current, different levels of electrical current were applied to cement paste and mortar specimens immediately after casting. I

  19. Evaluation of pulp and mortar to pack bitumen radioactive waste; Avaliacao de pastas e argamassas para o embalado de rejeitos radioativos betuminizados

    Energy Technology Data Exchange (ETDEWEB)

    Gregorio, Marina da S.; Vieira, Vanessa M.; Tello, Cledola C.O., E-mail: msg@cdtn.br, E-mail: vanessamotavieira@gmail.com, E-mail: tellocc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    According to international experience, for the deposition of cement in surface repository, is necessary the use of cement mortar pastes to immobilize the product. Determining the most efficient folder or for the packed mortar, as well as its ideal formulation, is the goal of this study. To do various experiments with samples of cement paste and mortar, with presence of fluxing and / or clay were performed. Viscosity, density, setting time and compressive strength were evaluated. This study will be presented only the results found in testing of compressive strength to be an essential parameter in the transport, storage and disposal of the product. From the results found will be selected the best formulations for use in packed bitumen tailings from the National Radioactive Waste Repository.

  20. Application of Image Analysis Based on SEM and Chemical Mapping on PC Mortars under Sulfate Attack

    Institute of Scientific and Technical Information of China (English)

    YU Cheng; SUN Wei; Scrivener Karen

    2014-01-01

    The degradation mechanisms of cementitious materials exposed to sulfate solutions have been controversial, despite considerable research. In this paper, two methodologies of image analysis based on scanning electron microscope and chemical mapping are used to analyse Portland cement mortars exposed to sodium sulfate solution. The effects of sulfate concentration in solution and water to cement ratio of mortar, which are considered as the most sensitive factors to sulfate attack, are investigated respectively by comparing the macro expansion with microstructure analysis. It is found that the sulfate concentration in pore solution, expressed as sulfate content in C-S-H, plays a critical role on the supersaturation with respect to ettringite and so on the expansion force generated.

  1. Properties of mortars made by uncalcined FGD gypsum-fly ash-ground granulated blast furnace slag composite binder.

    Science.gov (United States)

    Zhong, Shiyun; Ni, Kun; Li, Jinmei

    2012-07-01

    A series of novel mortars were developed from composite binder of uncalcined FGD gypsum, fly ash (FA) and ground granulated blast furnace slag (GGBFS) for the good utilization of flue gas desulphurization (FGD) gypsum. At a fixed ratio (20%) of GGBFS to the composite binder, keeping consistency of the mortar between 9.5 and 10.0 cm, the properties of the composite mortar were studied. The results show that higher water/binder (W/B) is required to keep the consistency when increasing the percentage of FGD gypsum. No obvious influences of the W/B and content of FGD gypsum on the bleeding of paste were observed which keeps lower than 2% under all experimental conditions tried. The highest compressive and flexural strengths (ratio is 20% FGD gypsum, 20% GGBFS and 60% FA) are 22.6 and 4.3 MPa at 28 days, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that massive ettringite crystals and C-S-H gels exist in the hydration products. At 90 days the mortars with FGD gypsum is dramatically smaller drying shrinkage (563-938 micro strain) than that without FGD gypsum (about 2250 micro strain). The release of the SO(4)(2-) from the mortar was analyzed, indicating that the dissolution of sulfate increases with FGD gypsum. The concentration of SO(4)(2-) releasing from the mortar with 10% FGD gypsum is almost equal to that obtained from the mortar without FGD gypsum. The release of SO(4)(2-) from the mortar with 20% FGD gypsum is 9200 mg·m(-2), which is lower than that from the mortar with 95% cement clinker and 5% FGD gypsum.

  2. Acoustic Behavior of Subfloor Lightweight Mortars Containing Micronized Poly (Ethylene Vinyl Acetate (EVA

    Directory of Open Access Journals (Sweden)

    Luiza R. Brancher

    2016-01-01

    Full Text Available This paper aims to contribute to acoustical comfort in buildings by presenting a study about the polymer waste micronized poly (ethylene vinyl acetate (EVA to be used in mortars for impact sound insulation in subfloor systems. The evaluation method included physical, mechanical and morphological properties of the mortar developed with three distinct thicknesses designs (3, 5, and 7 cm with replacement percentage of the natural aggregate by 10%, 25%, and 50% EVA. Microscopy analysis showed the surface deposition of cement on EVA, with preservation of polymer porosity. The compressive creep test estimated long-term deformation, where the 10% EVA sample with a 7 cm thick mortar showed the lowest percentage deformation of its height. The impact noise test was performed with 50% EVA samples, reaching an impact sound insulation of 23 dB when the uncovered slab was compared with the 7 cm thick subfloor mortar. Polymer waste addition decreased the mortar compressive strength, and EVA displayed characteristics of an influential material to intensify other features of the composite.

  3. Mechanical Properties and Solidiifed Mechanism of Tailings Mortar with Waste Glass

    Institute of Scientific and Technical Information of China (English)

    NING Baokuan; XU Jingwen; CHEN Sili

    2015-01-01

    In order to improve the comprehensive utilization of solid waste such as iron tailings and waste glass and so on, mechanical property test of cement tailings mortar mixed waste glass and curing mechanism research were conducted in the key materials mechanics lab of Liaoning province. The experimental results show that adding waste glass particles can improve the grain size distribution of tailings. The effect is proportional to the content. The compressive strength of tailings mortar has increased signiifcantly. The ifneness modulus of tailings mortar mixture adding waste glass powder was gradually reducing with the increase of the dosage of waste glass powder, but the compressive strength of the mixture has gradually enhanced with the increase of the dosage. Microscopic analysis shows that the waste glass particles in the mortar mainly play a role of coarse aggregate and glass powder after grinding fine below a certain size shows strong volcanic activity, which can act hydration with tailings, at the same time glass powder also, plays a role in ifne aggregate iflling. Therefore, all of glass particles and glass powder can be used as the additive material for improving and optimizing the mechanical property of tailings mortar.

  4. The effect of chemical admixtures and mineral additives on the properties of self-compacting mortars

    Energy Technology Data Exchange (ETDEWEB)

    Mustafa Sahmaran; Heru Ari Christianto; Ismail Ozgur Yaman [Middle East Technical University, Ankara (Turkey). Department of Civil Engineering

    2006-05-15

    Mortar serves as the basis for the workability properties of self-compacting concrete (SCC) and these properties could be assessed by self-compacting mortars (SCM). In fact, assessing the properties of SCM is an integral part of SCC design. The objective of this study was to evaluate the effectiveness of various mineral additives and chemical admixtures in producing SCMs. For this purpose, four mineral additives (fly ash, brick powder, limestone powder, and kaolinite), three superplasticizers (SP), and two viscosity modifying admixtures (VMA) were used. Within the scope of the experimental program, 43 mixtures of SCM were prepared keeping the amount of mixing water and total powder content (Portland cement and mineral additives) constant. Workability of the fresh mortar was determined using mini V-funnel and mini slump flow tests. The setting time of the mortars, were also determined. The hardened properties that were determined included ultrasonic pulse velocity and strength determined at 28 and 56 days. It was concluded that among the mineral additives used, fly ash and limestone powder significantly increased the workability of SCMs. On the other hand, especially fly ash significantly increased the setting time of the mortars, which can, however, be eliminated through the use of ternary mixtures, such as mixing fly ash with limestone powder. The two polycarboxyl based SPs yield approximately the same workability and the melamine formaldehyde based SP was not as effective as the other two.

  5. Improvement of Cracking-resistance and Flexural Behavior of Cement-based Materials by Addition of Rubber,Particles

    Institute of Scientific and Technical Information of China (English)

    KANG Jingfu; JIANG Yongqi

    2008-01-01

    By ring test and bend test,the improvement of waste tire rubber particles on the crack-resistance and flexural behaviors of cement-based materials were investigated.Test results show that the cracking time of the ring specimens can be retarded by the incorporation of rubber particles in the cement paste and mortar.The improvement in the crack-resistance depended on the rubber fraction.When the rubber fraction was 20%in volume,the cracking time was retarded about 15 h for the paste and 24 d for the mortar respectively.Flexural properties were evaluated based on the bend test results for both mortar and concrete containing different amount of rubber particles.Test results show that rubberized mortar and concrete specimens exhibit ductile failure and significant deformation before fracture.The ultimate deformations of both mortar and concrete specimen increase more than 2-4 times than control specimens.

  6. Leaching of metals from cement under simulated environmental conditions.

    Science.gov (United States)

    Lu, Huixia; Wei, Fang; Tang, Jingchun; Giesy, John P

    2016-03-15

    Leaching of metals from cement under various environmental conditions was measured to evaluate their environmental safety. A cement product containing clinker, which was produced from cement kiln co-processing of hazardous wastes, was solidified and leaching of metals was characterized using the 8-period test. Concentrations and speciation of metals in cements were determined. Effects of ambient environment and particle size on leachability of metals and mineralogical phases of cement mortars were evaluated by use of XRD and SEM. Results indicated that metals in cements were leachable in various media in descending order of: sea water, groundwater and acid rain. Cr, Ni, As, Co and V were leached by simulated sea water, while Cu, Cd, Pb, Zn, Mn, Sb and Tl were not leached in simulated sea water, groundwater or acid rain. When exposed to simulated acid rain or groundwater, amounts of Cr, Ni, As and V leached was inversely proportional to particle size of cement mortar. According to the one-dimensional diffusion equation, Cr was most leachable and the cumulative leached mass was predicted to be 9.6 mg kg(-1) after 20 years. Results of this study are useful in predicting releases of metals from cement products containing ash and clinkers cement kiln co-processing of hazardous wastes, so that they can be safely applied in the environment.

  7. Comportamento à compressão de argamassas reforçadas com fibras vegetais da Amazônia Behavior of cement mortar reinforced with Amazonian fibers subjected to compression

    Directory of Open Access Journals (Sweden)

    Marcelo de Souza Picanço

    2008-03-01

    matriz.In recent years, there has been intense research worldwide for alternative materials to substitute asbestos fiber, a component of asbestos cement, which has been found to be hazardous to human and animal health and has been banned in many countries. Since 1979 the Non-conventional Materials Research Group of PUC-Rio has carried out research on the application of vegetable fibers, available in abundance in Brazil, for the fabrication of construction components, aiming mainly at the fabrication of popular housing. The Curaúa fiber has been studied, as it is already of popular use in the manufacture of ropes, baskets and carpets in the region, known as Baixo Amazonas, in the state of Para, Brazil, where the first plantations have been organized on a commercial scale. In this work, mechanical properties of the Curauá fiber, as well as their application as a cementicious matrix reinforcement, have been studied. The performance of Curauá fiber and its composites was compared with other vegetable fibers, such as sisal and jute, as a substitute for asbestos fiber and its composites. The data on sisal fibres from previous works by the same research group at PUC-Rio was considered for comparison. The behavior of jute fiber, as well as cementicious composites, reinforced with jute and sisal fibers, has also been studied in this work. The results have shown that the Curauá fiber has appropriate physical and mechanical characteristics that make it suitable to be used as reinforcement of cementicious matrixes, with a high ductility and post-cracking resistance capacity.

  8. Strengthening of two-way reinforced concrete slabs with Textile Reinforced Mortars (TRM)

    OpenAIRE

    Papanicolaou, Catherine; Triantafillou, Thanasis; Papantoniou, Ioannis; Balioukos, Christos

    2009-01-01

    An innovative strengthening technique is applied for the first time in this study to provide flexural strengthening in two-way reinforced concrete (RC) slabs supported on edge beams. The technique comprises external bonding of textiles on the tension face of RC slabs through the use of polymer-modified cement- based mortars. The textiles used in the experimental campaign comprised fabric meshes made of long stitch-bonded fibre rovings in two orthogonal directions. The specimens measured 2 x 2...

  9. Mechanical strength development of mortars containing volcanic scoria-based binders with different fineness

    Directory of Open Access Journals (Sweden)

    Aref M. al-Swaidani

    2016-06-01

    Full Text Available The benefits of using natural pozzolan as cement replacement are often associated with shortcomings such as the need to moist-curing for longer time and a reduction of strength at early ages. The objective of the study is to investigate the influence of binder fineness on the mechanical strength development of scoria-based binder mortars. In the study, mortar specimens have been produced with four types of binder: one plain Portland cement (control and three scoria-based binders with three replacement levels: 25%, 30% and 35%, respectively. All scoria-based binders have been inter-ground into four different Blaine fineness: 2400, 3200, 4200 and 5100 cm2/g. The development of the compressive and flexural tensile strength of all mortar specimens with curing time has been investigated. The effects of the Blaine fineness of the scoria-based blended cement on the compressive and flexural strengths of mortar have been evaluated at curing ages of 2, 7, 28 and 90 days, respectively. Particle size distribution measured by a laser diffractometer has been considered in the study. Test results revealed that there is a decrease in strength with increasing amounts of scoria. In addition, there was found an increase in strength with increasing the Blaine fineness values. No direct relationship between Blaine and particle size distribution was observed. Effects of Blaine fineness on some physical properties of blended cements such as water demand, setting times and soundness have also been investigated. Further, an estimation equation for strength development incorporating the effects of fineness measured either by Blaine or by particle size distribution has been derived by the authors.

  10. Early-age hydration and volume change of calcium sulfoaluminate cement-based binders

    Science.gov (United States)

    Chaunsali, Piyush

    Shrinkage cracking is a predominant deterioration mechanism in structures with high surface-to-volume ratio. One way to allay shrinkage-induced stresses is to use calcium sulfoaluminate (CSA) cement whose early-age expansion in restrained condition induces compressive stress that can be utilized to counter the tensile stresses due to shrinkage. In addition to enhancing the resistance against shrinkage cracking, CSA cement also has lower carbon footprint than that of Portland cement. This dissertation aims at improving the understanding of early-age volume change of CSA cement-based binders. For the first time, interaction between mineral admixtures (Class F fly ash, Class C fly ash, and silica fume) and OPC-CSA binder was studied. Various physico-chemical factors such as the hydration of ye'elimite (main component in CSA cement), amount of ettringite (the main phase responsible for expansion in CSA cement), supersaturation with respect to ettringite in cement pore solution, total pore volume, and material stiffness were monitored to examine early-age expansion characteristics. This research validated the crystallization stress theory by showing the presence of higher supersaturation level of ettringite, and therefore, higher crystallization stress in CSA cement-based binders. Supersaturation with respect to ettringite was found to increase with CSA dosage and external supply of gypsum. Mineral admixtures (MA) altered the expansion characteristics in OPC-CSA-MA binders with fixed CSA cement. This study reports that fly ash (FA) behaves differently depending on its phase composition. The Class C FA-based binder (OPC-CSA-CFA) ceased expanding beyond two days unlike other OPC-CSA-MA binders. Three factors were found to govern expansion of CSA cement-based binders: 1) volume fraction of ettringite in given pore volume, 2) saturation level of ettringite, and 3) dynamic modulus. Various models were utilized to estimate the macroscopic tensile stress in CSA cement

  11. Sodium Sulphate Effect on Cement Produced with Building Stone Waste

    Directory of Open Access Journals (Sweden)

    Emre Sancak

    2015-01-01

    Full Text Available In this study, the blended cements produced by using the building stone waste were exposed to sulphate solution and the cement properties were examined. Prepared mortar specimens were cured under water for 28 days and then they were exposed to three different proportions of sodium sulphate solution for 125 days. Performances of cements were determined by means of compressive strength and tensile strength tests. The broken parts of some mortar bars were examined with scanning electron microscope (SEM. Besides, they were left under moist atmosphere and their length change was measured and continuously monitored for period of 125 days. In blended cements, solely cements obtained by replacing 10–20% of diatomites gave similar strength values with ordinary Portland cement (CEM I 42.5R at the ages of 7, 28, and 56 days. In all mortar specimens that included either waste andesite (AP or marble powder (MP showed best performance against very severe effective sodium sulphate solutions (13500 mg/L.

  12. Influence of portland cement replacement in high calcium fly ash geopolymer paste

    Directory of Open Access Journals (Sweden)

    Tanakorn Phoo-ngernkham

    2014-03-01

    Full Text Available This article presents the influence of ordinary Portland cement (OPC replacement in high calcium fly ash (FA geopolymer paste. FA was used to replace OPC at the rate of 5, 10 and 15% by mass of binder. Sodium silicate (Na2SiO3 and 10 molar sodium hydroxide (NaOH solutions were used as the alkaline solution in the reaction. The Na2SiO3/NaOH ratio of 2.0 and the liquid/binder (L/B ratio of 0.60 were used in all mixtures. The results of increase OPC replacement, the setting time and compressive strain capacity decreased while the compressive strength and modulus of elasticity increased. The compressive strength and modulus of elasticity at 28 days of geopolymer pastes with 15% OPC replacement were 36.7 MPa and 13,300 MPa, respectively.

  13. 3D Simulation of micromechanical behavior of cement paste

    NARCIS (Netherlands)

    Qian, Z.; Ye, G.; Schlangen, H.E.J.G.; Van Breugel, K.

    2010-01-01

    Numerical modeling of fracture processes of brittle materials, such as cement paste, mortar, concrete and rocks, started in the late 1960s when the discrete and smeared cracking models were introduced. In the 1990s, Schlangen and van Mier proposed another numerical model to compensate the drawbacks

  14. New OPC verification method using die-to-database inspection

    Science.gov (United States)

    Yang, Hyunjo; Choi, Jaeseung; Cho, Byungug; Hong, Jongkyun; Song, Jookyoung; Yim, Donggyu; Kim, Jinwoong; Yamamoto, Masahiro

    2006-03-01

    The minimum feature size of new generation memory devices is approaching down to 50 nm era. And a very precise CD control is demanded not only for cell layouts but also for core and peripheral layouts of DRAM devices. However, as NA of lens system grows higher and higher and Resolution Enhancement Techniques (RETs) becomes more and more aggressive, isolated-dense bias increases and process window for the core and peripheral layouts decreases dramatically. So, the burden of OPC increases in proportion and it is requisite to verify as many features as possible on wafer. If possible, it would be desirable to verify all the features in a die. Recently, a novel inspection tool has been developed which can verify all kinds of patterns on wafer based on Die to Database copmarison method. It can identify all the serious systematic defects of nm order size error from the original layout target and feed back the systematic error points to OPC for more accurate model tuning. In addition we can obtain the full field CD distribution diagram of some specific transistors with hundreds of thousands of measurement data. So, we can analyze the root cause of the CD distribution in a field, such as mask CDU or lens aberrations and so on. And we can also perform Process Window Qualification of all the features in a die. In this paper, OPC verification methodology using the new inspection tool will be introduced and the application to the analysis of full field CD distribution and Process Window Qualification will be presented in detail.

  15. 7nm logic optical lithography with OPC-Lite

    Science.gov (United States)

    Smayling, Michael C.; Tsujita, Koichiro; Yaegashi, Hidetami; Axelrad, Valery; Nakayama, Ryo; Oyama, Kenichi; Yamauchi, Shohei; Ishii, Hiroyuki; Mikami, Koji

    2015-03-01

    The CMOS logic 22nm node was the last one done with single patterning. It used a highly regular layout style with Gridded Design Rules (GDR). Smaller nodes have required the same regular layout style but with multiple patterning for critical layers. A "line/cut" approach is being used to achieve good pattern fidelity and process margin.[1] As shown in Fig. 1, even with "line" patterns, pitch division will eventually be necessary. For the "cut" pattern, Design-Source-Mask Optimization (DSMO) has been demonstrated to be effective at the 20nm node and below.[2,3,4] Single patterning was found to be suitable down to 16nm, while double patterning extended optical lithography for cuts to the 10-12nm nodes. Design optimization avoided the need for triple patterning. Lines can be patterned with 193nm immersion with no complex OPC. The final line dimensions can be achieved by applying pitch division by two or four.[5] In this study, we extend the scaling using simplified OPC to the 7nm node for critical FEOL and BEOL layers. The test block is a reasonably complex logic function with ~100k gates of combinatorial logic and flip-flops, scaled from previous experiments. Simulation results show that for cuts at 7nm logic dimensions, the gate layer can be done with single patterning whose minimum pitch is 53nm, possibly some of the 1x metal layers can be done with double patterning whose minimum pitch is 53nm, and the contact layer will require triple patterning whose minimum pitch is 68nm. These pitches are less than the resolution limit of ArF NA=1.35 (72nm). However these patterns can be separated by a combination of innovative SMO for less than optical resolution limit and a process trick of hole-repair technique. An example of triple patterning coloring is shown in Fig 3. Fin and local interconnect are created by lines and trims. The number of trim patterns are 3 times (min. pitch=90nm) and twice (min. pitch=120nm), respectively. The small number of masks, large pitches, and

  16. 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)

  17. Effect of Metakaolin on Strength and Efflorescence Quantity of Cement-Based Composites

    OpenAIRE

    Tsai-Lung Weng; Wei-Ting Lin; An Cheng

    2013-01-01

    This study investigated the basic mechanical and microscopic properties of cement produced with metakaolin and quantified the production of residual white efflorescence. Cement mortar was produced at various replacement ratios of metakaolin (0, 5, 10, 15, 20, and 25% by weight of cement) and exposed to various environments. Compressive strength and efflorescence quantify (using Matrix Laboratory image analysis and the curettage method), scanning electron microscopy, and X-ray diffraction anal...

  18. COMPRESSIVE STRENGTH TESTING OF EARTH MORTARS

    Directory of Open Access Journals (Sweden)

    Givanildo Alves Azeredo

    2007-06-01

    Full Text Available This paper discusses the compressive strength of earth mortars. The goal is to use these mortars for masonry construction. Although it is necessary to study the whole masonry behaviour, the scope of this paper refers to the mortar only, without taking into account the blocks. As with other masonry units, compressive strength is a basic measure of quality for masonry mortars. However, there is a great variety of methodology for determining their parameters and properties, such as different samples geometry, the way strains are measured and also the platen restraint effect adopted. The present paper outlines certain experimental devices used to determine compressive strength of earth mortars and tries to show their influence on the properties determined. Proposals for the future development of testing earth mortars are outlined.

  19. A study on the effect of nano silica on compressive strength of high volume fly ash mortars and concretes

    International Nuclear Information System (INIS)

    Highlights: • The addition of NS compensates low early age compressive strength of HVFA system. • NS also contributes to later age compressive strength gain of HVFA system. • The XRD results confirm the reduction of CH in HVFA paste due to addition of NS. - Abstract: This paper presents the effect of nano silica (NS) on the compressive strength of mortars and concretes containing different high volume fly ash (HVFA) contents ranging from 40% to 70% (by weight) as partial replacement of cement. The compressive strength of mortars is measured at 7 and 28 days and that for concretes is measured at 3, 7, 28, 56 and 90 days. The effects of NS in microstructure development and pozzolanic reaction of pastes containing above HVFA contents are also studied through backscattered electron (BSE) image and X-ray diffraction (XRD) analysis. Results show that among different NS contents ranging from 1% to 6%, cement mortar containing 2% NS exhibited highest 7 and 28 days compressive strength. This NS content (2%) is then added to the HVFA mortars and concretes and the results show that the addition of 2% NS improved the early age (7 days) compressive strength of mortars containing 40% and 50% fly ash by 5% and 7%, respectively. However, this improvement is not observed at high fly ash contents beyond 50%. On the other hand, all HVFA mortars exhibited improvement in 28 days compressive strength due to addition of 2% NS and the most significant improvement is noticed in mortars containing more than 50% fly ash. In HVFA concretes, the improvement of early age (3 days) compressive strength is also noticed due to addition of 2% NS. The BSE and XRD analysis results also support the above findings

  20. Immobilisation of ion exchange resins in cement

    International Nuclear Information System (INIS)

    Over the last seven years, Low Oxidation State Metal Ion reagents (LOMI) have been used to decontaminate the 100 MW(e) Steam Generating Heavy Water Ractor (SGHWR) at Winfrith. The use of these reagents has resulted in a dilute ionic solution containing activation products which are produced by corrosion of metallic components in the reactor. It has been demonstrated that the amount of activity in the solution can be reduced using organic ion exchanger resins. These resins consist of a cross linked polystyrene with sulphonic acid or quaternary ammonium function groups and can be successfully immobilised in blended cement systems. The formulation which has been developed is produced from a 9 to 1 blend of ground granulated blast furnace slag (BFS) and ordinary Portland cement (OPC) containing 28% ion exchange resin in the water saturated form. If 6% Microsilica is added to the blended cement the waste loading can be increased to 36 w/o. (author)

  1. Corrosion Resistance of Calcium Aluminate Cement Concrete Exposed to a Chloride Environment

    Directory of Open Access Journals (Sweden)

    Ki Yong Ann

    2014-01-01

    Full Text Available The present study concerns a development of calcium aluminate cement (CAC concrete to enhance the durability against an externally chemically aggressive environment, in particular, chloride-induced corrosion. To evaluate the inhibition effect and concrete properties, CAC was partially mixed with ordinary Portland cement (OPC, ranging from 5% to 15%, as a binder. As a result, it was found that an increase in the CAC in binder resulted in a dramatic decrease in the setting time of fresh concrete. However, the compressive strength was lower, ranging about 20 MPa, while OPC indicated about 30–35 MPa at an equivalent age. When it comes to chloride transport, there was only marginal variation in the diffusivity of chloride ions. The corrosion resistance of CAC mixture was significantly enhanced: its chloride threshold level for corrosion initiation exceeded 3.0% by weight of binder, whilst OPC and CAC concrete indicated about 0.5%–1.0%.

  2. Natural cement in the nineteenth century city of Madrid. Identification of their application, conservation status and their compatibility with moderns cements.

    Science.gov (United States)

    Corrochano, Cristina Mayo; Lasheras Merino, Felix; Sanz-Arauz, David

    2016-04-01

    Roman cement was patented in 1796 and it arrived to Spain in 1835. Although the natural cement used in Madrid came mainly from Guipúzcoa's factories, there were a few small factories producing natural cement in the area. In the south east of Madrid, in "Morata de Tajuña", are the marl quarries of the Madrid Community. Natural cement was extensively used to decorate buildings in Madrid during the 19th century and the beginning of the 20th. It was highly demanded in various sectors of civil engineering: sewerage, water supply, canals, ports and tunnels. In the building sector, at first the use of cements was limited to building foundations and masonry mortars, but never as render mortar because it was considered an unsightly and vulgar material. For renders still traditional lime mortar was used. And is not till the end of the 19th century when it was used in facade decorations for the first time. We have analysed 25 buildings in Madrid built in that period of time. It was used microscopy techniques for the identification of these cements, checking how many of them used natural cement, how they used it, what is its conservation status and their compatibility with modern cements.

  3. Effect of Concentration of Sodium Hydroxide and Degree of Heat Curing on Fly Ash-Based Geopolymer Mortar

    OpenAIRE

    Subhash V. Patankar; Ghugal, Yuwaraj M.; Jamkar, Sanjay S.

    2014-01-01

    Geopolymer concrete/mortar is the new development in the field of building constructions in which cement is totally replaced by pozzolanic material like fly ash and activated by alkaline solution. This paper presented the effect of concentration of sodium hydroxide, temperature, and duration of oven heating on compressive strength of fly ash-based geopolymer mortar. Sodium silicate solution containing Na2O of 16.45%, SiO2 of 34.35%, and H2O of 49.20% and sodium hydroxide solution of 2.91, 5.6...

  4. Test on Sensor Effect of Cement Matrix Piezoelectric Composite

    Institute of Scientific and Technical Information of China (English)

    YANG Xiaoming; LI Zhongxian; DING Yang; LI Zongjin

    2005-01-01

    A novel cement matrix smart piezoelectric composite and its application as sensing element are presented.A cement matrix smart piezoelectric composite piece encapsulated in a cement mortar formed a practical sensor, and it was tested on material test system with cyclic loading.According to the theoretical analysis, the function of the cement matrix piezoelectric sensor output voltage was expressed in terms of the magnitude of the input cyclic loading amplitude and frequency.The curve fitting of gain function that is defined as sensor′s gain factor under different frequencies of input loading was carried out. From the results of curve fitting, it is found that the cement matrix smart piezoelectric composite has a simple relationship between input loading and output voltage.Therefore the cement matrix piezoelectric composite sensor is suitable to be applied in structural health monitoring.

  5. Corrosion Resistance of Calcium Aluminate Cement Concrete Exposed to a Chloride Environment

    OpenAIRE

    Ki Yong Ann; Chang-Geun Cho

    2014-01-01

    The present study concerns a development of calcium aluminate cement (CAC) concrete to enhance the durability against an externally chemically aggressive environment, in particular, chloride-induced corrosion. To evaluate the inhibition effect and concrete properties, CAC was partially mixed with ordinary Portland cement (OPC), ranging from 5% to 15%, as a binder. As a result, it was found that an increase in the CAC in binder resulted in a dramatic decrease in the setting time of fresh concr...

  6. Properties and durability of metakaolin blended cements

    Directory of Open Access Journals (Sweden)

    Ezzat, El-Sayed

    2010-09-01

    Full Text Available This paper evaluates the optimal calcination temperature and replacement ratio to ensure high metakaolin (MK pozzolanicity in blended cement. The MK used was prepared by firing two types of local at temperatures ranging from 700 to 850 ºC. Dry blends of ordinary Portland cement (OPC and varying proportions of MK were mixed with the amount of water required to ensure optimal consistency of the resulting pastes. The specimens were cured at 100% RH for 24 h and then immersed in water for 3, 7, 28, 90 or 180 days. At each test time, the degree of hydration and compressive strength of the hardened cement pastes were measured The findings showed that the most suitable calcination temperature to obtain metakaolin is 700 ºC, while the optimal replacement ratio ranges from 25 to 30%. DTA was used to determine the phases comprising the hydration products forming at the ages studied. Pure OPC and OPC-MK specimens were immersed in 3% NaCl and 5% MgSO4 solutions for 30, 90 and 180 days to measure their durability. The OPC-MK pastes immersed in the 3% NaCl solution were observed to be highly resistant to chloride attack.

    El presente trabajo evalúa el comportamiento puzolánico de metacaolín (MK, producto de la calcinación a distintas temperaturas de dos tipos de caolín local de composiciones químicas diferentes, al incorporarse al cemento en diferentes proporciones. Se preparó un cemento adicionado mediante la mezcla en seco de cemento Portland ordinario (OPC y metacaolín (MK, a los que se añadió la cantidad óptima de agua para obtener una pasta de la consistencia deseada. Las probetas se curaron a una HR del 100% durante 24 horas, sumergiéndose posteriormente en agua durante 3, 7, 28, 90 o 180 días. A cada tiempo de ensayo se controló el grado de hidratación de las pastas endurecidas y se comprobó la resistencia a la compresión de las probetas cúbicas a las edades de curado establecidas. Los resultados obtenidos indican que la

  7. 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

  8. The Effect of VAc-VeoVa10 Latex Powder on Mechanical Properties of Modified Mortar%VAc-VeoVa10乳胶粉对改性水泥砂浆力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    程祥龙; 班倩; 滕朝辉; 夏大寒; 申迎华

    2012-01-01

    According to the bad caking property and flexibility of cement mortar used in external thermal insulation system, Vac-VeoVa10 latex powder was used to modify the cement mortar. The effect of dosage of Vac-VeoVa10 latex powder on mechanical properties of modified mortar was studied. The results show that with the increase of dosage of latex powder, both the bond strength between modified mortar and expanded polystyrene boards (EPS), and the strength between modified mortar and cement mortar block increased; the flexural strength and flexibility were improved, but the compressive strength decreased. At the same time, the influence of cement/sand ratio, dosage of Vac-VeoVa10 and dosage of water retaining agent on mortar performance was analyzed by orthogonal test, including the bond strength between modified mortar and expanded polystyrene boards (EPS), the strength between modified mortar and cement mortar block by compressive strength,flexural strength,and ratio of compressive strength to flexural strength. By comprehensive consideration, at the cement/sand ratio 1:1, the mass fraction of polymer powder 4% ,and the mass fraction of water retaining agent 0. 2%, the properties of modified mortar was the best.%针对目前膨胀聚苯板(EPS)外墙外保温系统用水泥砂浆粘结性差、柔韧性差等问题,用醋酸乙烯酯(VAc)与叔碳酸乙烯酯(VeoVa10)共聚乳胶粉对其进行改性.研究了乳胶粉用量对改性水泥砂浆力学性能的影响.结果表明,随着乳胶粉用量的增加,砂浆的粘结强度增加、抗折强度提高、抗压强度降低、柔韧性提高.通过正交试验研究了灰砂质量比、乳胶粉用量、保水剂用量等因素对改性水泥砂浆与EPS以及与基础砂浆粘结强度、抗折强度、抗压强度以及压折比的影响,得出改性水泥砂浆的最优配比为:水泥与石英砂的质量比1∶1,乳胶粉质量分数4%,保水剂质量分数0.2%.

  9. Effects of the restoration mortar on chalk stone buildings

    Science.gov (United States)

    Ion, R. M.; Teodorescu, S.; Ştirbescu, R. M.; Dulamă, I. D.; Şuică-Bunghez, I. R.; Bucurică, I. A.; Fierăscu, R. C.; Fierscu, I.; Ion, M. L.

    2016-06-01

    The monument buildings as components of cultural heritage are exposed to degradation of surfaces and chemical and mechanical degradation, often associated to soiling and irreversible deterioration of the building. In many conservative and restorative works, a cement-based mortar was used without knowing all the adverse effects of this material on the building. This paper deals with the study of the effects of natural cement used in restorative works in the particular case of the Basarabi-Murfatlar Churches Ensemble. Cement-based materials exposed to sulfate present in the chalk stone - gypsum (CaSO4.2H2O), can induce signs of deterioration, due to ettringite ([Ca3Al (OH)612H2O]2(SO4)32H2O) or thaumasite (Ca3[Si(OH)612H2O](CO3)SO4) formation. These phases contribute to strain within the material, inducing expansion, strength loss, spalling and severe degradation. Several combined techniques (XRD, EDXRF, ICP-AES, SEM, EDS, sulphates content, FT-IR and Raman analysis were carried out to put into evidence the effects of them on the building walls.

  10. Rendering mortars in Medina Azahara, Part I: Material characterization and alteration process

    Directory of Open Access Journals (Sweden)

    Blanco-Varela, M. T.

    1997-03-01

    Full Text Available Rendering mortars, which are still exposed to the open air on some of the walls of Medina Azahara, are studied and characterized in this work. Some repairing mortars used in different previous restorations are also characterized. Those rendering mortars are of different make considering the composition of their binder: lime, gypsum and mixed lime/ gypsum. Repairing mortars used in previous interventions are made of lime, excepting for a portland cement used by Félix Hernández in the restoration of one of the rooms back in the 50's. Biological colonization is the main cause of decay in lime mortars, while in mortars made of gypsum, decay is a result of the solubilizating action of rain water.

    En este trabajo se analizan y caracterizan los revocos que, todavía hoy, permanecen sobre algunos paramentos de los muros de la ciudad de Medina Azahara, expuestos a la intemperie. También se caracterizan algunos de los molleros de reparación aplicados en las distintas restauraciones de los revocos. Los revocos están formados por tres clase de morteros, atendiendo a la composición de su ligante: de cal, de yeso y bastardos de cal y yeso. Los morteros de reparación que se han utilizado son de cal, a excepción del utilizado en la restauración de Félix Hernández (década de 1950, en una de las salas, que es de cemento portland. La colonización biológica es la principal causa de deterioro de los morteros de cal, en tanto que la solubilización por las aguas de lluvia lo es en los morteros que contienen yeso.

  11. Study on Thermal Conductivity of PVC Plastic Mortar%PVC 塑料砂浆导热性研究∗

    Institute of Scientific and Technical Information of China (English)

    张海波; 师广岭; 尚海涛; 于连林

    2015-01-01

    The heat-insulating properties of cement mortar can be improved by adding polyvinyl chloride(PVC) plastic aggregates.A series model and a parallel models of thermal conductivity of cement mortar were established,to study the effect of PVC plastic aggregates on thermal conductivity of cement mortar and the heat transmission mode in the mortar.According to the results,a series-parallel hybrid model of thermal conductivity of PVC plastic mortar were further proposed.The study showed that the theoretical values calculated by the series-parallel hybrid model agreed well with the experimental values.%水泥砂浆中加入聚氯乙烯(PVC)塑料骨料可以改善砂浆的保温性能,为了探索热流在砂浆中的传输方式及研究 PVC 塑料骨料对水泥砂浆导热系数的影响,建立了水泥砂浆的串联导热模型与并联导热模型,根据实验结果进一步提出了 PVC 塑料砂浆串并联混合导热模型,研究表明由串并联混合模型计算出的理论值与实测值呈现出了良好的一致性。

  12. Cement mortar resistance to corrosion caused by magnesium salt solutions

    Directory of Open Access Journals (Sweden)

    García de Paredes y Gaibrois, Pablo

    1974-12-01

    Full Text Available Not availableEntre los agentes químicos que destruyen a los morteros y hormigones elaborados con conglomerantes hidráulicos, silícicos o aluminosos, inspira mucho temor el catión magnesio, principalmente si en las disoluciones acuosas le acompañan los aniones sulfato y/o cloruro. Por esta razón el trabajo del Sr. Riedel adquiere especial interés, tanto más cuánto no es numerosa ni resolutiva la experiencia expuesta en la literatura.

  13. Influence of calcium sulfoaluminate cement on the pullout performance of reinforcing fibers: An evaluation of the micro-mechanical behavior

    Science.gov (United States)

    Jewell, Robert Benjamin

    The objective of this research was to determine the influence of calcium sulfoaluminate (CSA) cement on reinforcing fibers by evaluating the fiber pullout behavior, and bonding characteristics, of a single fiber embedded in a cementitious paste matrix. Four types of fibers commonly used in industry were evaluated: 1) Polyvinyl alcohol; 2) Polypropylene; 3) Coated Steel; and 4) Plain Steel. Upward trends in energy costs and potential greenhouse gas regulations favor an increased use of construction materials that require lower energy and lower CO2 emissions to fabricate, such as CSA cement, as opposed to the production of ordinary portland cement (OPC), which is more energy intensive and produces more CO2 emissions. However, widespread use of CSA cement requires a more in-depth understanding of the engineering characteristics that govern its performance, including interaction with reinforcing fibers. The overarching objective of this research was to provide the engineering base needed for the utilization of reinforcing fibers in CSA cement-based construction materials. The aims of the research were (1) to develop an ettringite-rich calcium sulfoaluminate cement, and (2) evaluate the pullout characteristics of reinforcing fibers embedded in a CSA-cement matrix. Key elements of the strategy included (1) Compare the performance of a laboratory-fabricated CSA cement to a commercial CSA cement and OPC, (2) Evaluate the peak load, and toughness of reinforcing fibers in CSA cement and OPC, (3) Evaluate the debonding-energy density and multiple-cracking behavior of fibers in CSA cement and OPC, and (4) Evaluate the shear bond strength of reinforcing fibers in CSA cement and OPC. Based on the findings of this PhD dissertation, calcium sulfoaluminate cement has a significant influence on the characteristics and behavior of embedded reinforcing fibers. An important factor contributing to the bond strength between fiber and matrix was the ability to transfer interfacial

  14. Studies on termite hill and lime as partial replacement for cement in plastering

    Energy Technology Data Exchange (ETDEWEB)

    Olusola, K.O.; Olanipekun, E.A.; Ata, O.; Olateju, O.T. [Obafemi Awolowo University, Ile-Ife, Osun State (Nigeria). Department of Building

    2006-03-15

    This study investigated the compressive strength and water absorption capacity of 50x50x50mm mortar cubes made from mixes containing lime, termite hill and cement and sand. Two mix ratios (1:4 and 1:6) and varying binder replacements of cement with lime or termite hill amounting to 0%, 10%, 20%, 30%, 40% and 50% were used. Test results showed that the compressive strength of the mortar cubes increases with age and decreases with increasing percentage replacement of cement with lime and termite hill. However, for mix ratio 1:6, up to 20% replacement of cement with either lime or termite hill, all the mortar cubes had the same strength; subsequently, the termite hill exhibited a higher compressive strength. For mix ratio 1:4, mortar cubes made from lime/cement and termite hill/cement mixtures had the same strength at 50% replacement. Generally, water absorption is higher in mixtures containing lime (18.10% and 14.20% for mix ratios 1:6 and 1:4, respectively, both at 50% replacement level) than those containing termite hill (16.10% and 13.02% for mix ratios 1:6 and 1:4, respectively, both at 50% replacement level). Termite hills seem to be promising as a suitable, locally available housing material for plastering. (author)

  15. Casting granular ion exchange resins with medium-active waste in cement

    International Nuclear Information System (INIS)

    Medium active waste from nuclear power stations in Sweden is trapped in granular ion exchange resins. The resin is mixed with cement paste and cast in a concrete shell which is cubic and has an edge dimension of 1.2 m. In some cases the ion exchange cement mortar has cracked. The report presents laboratory sutdies of the properties of the ion exchange resin and the mortar. Also the leaching of the moulds has been investigated. It was shown that a mixture with a water cement ratio higher than about 0.5 swells considerably during the first weeks after casting. The diffusion constant for cesium 137 has been determined at 3.10-4 cm2/24-hour period in conjunction with exposure of the mould and mortar to sea water. The Swedish language report has 400 pages with 90 figures and 30 tables. (author)

  16. Estimates of zooplankton abundance and size distribution with the Optical Plankton Counter (OPC)

    DEFF Research Database (Denmark)

    Wieland, Kai; Petersen, D.; Schnack, D.

    1997-01-01

    and widely overlapping size ranges prevented a detailed analysis of the fine scale vertical distribution and the horizontal variability of abundance for distinct species. These results are used to discuss the limitations of the OPC for rapid and continuous surveying of spatial distribution and abundance......The capability of the Optical Plankton Count er (OPC) to examine the abundance and size distribution of zooplankton was tested in Storfjorden, Norway, in June 1993. Selected material obtained from net sampling was measured with a laboratory version of the OPC and compared with microscope analysis...... in order to identify main species in the in situ size frequency distributions obtained by the submersible version of the OPC. Differences in the particle concentration between shallow and deep water layers were clearly resolved by the submersible OPC, but the high diversity of the zooplankton community...

  17. Testing Machine for Expansive Mortar

    CERN Document Server

    Silva, Romulo Augusto Ventura

    2011-01-01

    The correct evaluation of a material property is fundamental to, on their application; they met all expectations that were designed for. In development of an expansive cement for ornamental rocks purpose, was denoted the absence of methodologies and equipments to evaluate the expansive pressure and temperature of expansive cement during their expansive process, having that data collected in a static state of the specimen. In that paper, is described equipment designed for evaluation of pressure and temperature of expansive cements applied to ornamental rocks.

  18. Damage diagnosis and compatible repair mortars

    NARCIS (Netherlands)

    Hees, R.P.J. van

    1999-01-01

    Mortars for repair and maintenance of historic masonry have to meet specific requirements. Several authors have made contributions, however many cases of failure show that there still is quite a lack of knowledge on the compatibility of repair mortars for historic masonry. The diagnosis of the cause

  19. Simple Analysis of Historical Lime Mortars

    Science.gov (United States)

    Pires, Joa~o

    2015-01-01

    A laboratory experiment is described in which a simple characterization of a historical lime mortar is made by the determination of its approximate composition by a gravimetric method. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) are also used for the qualitative characterization of the lime mortar components. These…

  20. Performance of portland limestone cements: Cements designed to be more sustainable that include up to 15% limestone addition

    Science.gov (United States)

    Barrett, Timothy J.

    In 2009, ASTM and AASHTO permitted the use of up to 5% interground limestone in ordinary portland cement (OPC) as a part of a change to ASTM C150/AASHTO M85. When this work was initiated a new proposal was being discussed that would enable up to 15% interground limestone cement to be considered in ASTM C595/AASHTO M234. This work served to provide rapid feedback to the state department of transportation and concrete industry for use in discussions regarding these specifications. Since the time this work was initiated, ASTM C595/AASHTO M234 was passed (2012c) and PLCs are now able to be specified, however they are still not widely used. The proposal for increasing the volume of limestone that would be permitted to be interground in cement is designed to enable more sustainable construction, which may significantly reduce the CO2 that is embodied in the built infrastructure while also extending the life of cement quarries. Research regarding the performance of cements with interground limestone has been conducted by the cement industry since these cements became widely used in Europe over three decades ago, however this work focuses on North American Portland Limestone Cements (PLCs) which are specifically designed to achieve similar performance as the OPCs they replace.This thesis presents a two-phase study in which the potential for application of cements containing limestone was assessed. The first phase of this study utilized a fundamental approach to determine whether cement with up to 15% of interground or blended limestone can be used as a direct substitute to ordinary portland cement. The second phase of the study assessed the concern of early age shrinkage and cracking potential when using PLCs, as these cements are typically ground finer than their OPC counterparts. For the first phase of the study, three commercially produced PLCs were obtained and compared to three commercially produced OPCs made from the same clinker. An additional cement was tested