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Sample records for modified mortar adhesion

  1. 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.

  2. Mortar modified with sulfonated polystyrene produced from waste plastic cups

    Directory of Open Access Journals (Sweden)

    L. A. C. MOTTA

    Full Text Available Abstract In this work, we studied the addition of sulfonated polystyrene produced from waste plastic cups as an admixture for mortars. Mortars were analyzed with polystyrene content of 0.0; 0.2; 0.6; 1.0 and 1.4% in relation to the cement mass. The influence of polystyrene on the mortars' properties was evaluated by the consistency index, water retention, water absorption, porosity, elasticity modulus, compressive strength, flexural strength, bond tensile strength and microscopy. The increase in the sulfonated polystyrene content decreased the elasticity modulus of the mortar and, despite higher porosity, there was a reduction of water absorption by capillarity. In relation to mortar without admixture, the modified mortar showed an increase in water retention and consistency index, and a large increase in flexural strength and bond tensile strength. The significant increase of bond tensile strength (214% with admixture 1% highlights the potential of the produced material as an adhesive mortar.

  3. Quartzite mining waste for adhesive mortar production

    International Nuclear Information System (INIS)

    Dias, L.S.; Mol, R.M.R.; Silva, K.D.C.; Campos, P.A.M.; Mendes, J.C.; Peixoto, R.A.F.

    2016-01-01

    The construction sector is responsible for a high consumption of natural resources. Moreover, the mining industry generates and discard waste improperly in the environment aggravating environmental problems. In order to reduce the natural sand extraction and provide the environmentally correct disposal of mining waste, this work proposes the use of quartzite mining waste to replace natural sand for the production of adhesive mortars. The quartzite mining tailings was chemically characterized using X-ray fluorescence, and morphologically by optical microscopy. In sequence, the mortars were subjected to characterization tests in the fresh state as consistency index, slip, water retention, entrained air content, bulk density and Squeeze Flow. The results were satisfactory, indicating the viability of this material as fine aggregate in total replacement of natural aggregate, allowing the reduction of environmental impacts. (author)

  4. Characterization of Incorporation the Glass Waste in Adhesive Mortar

    Science.gov (United States)

    Santos, D. P.; Azevedo, A. R. G.; Hespanhol, R. L.; Alexandre, J.

    Ehe search for reuse generated waste in urban centers, intending to preserve natural resources, has remained fairly constant, both in context of preventing exploitation of resources as the emplacement of waste on the environment. Glass waste glass created a serious environmental problem, mainly because of inconsistency of its flows. Ehe use of this product as a mineral additive, finely ground, cement replacement and aggregate is a promising direction for recycling. This work aims to study the influence of glass waste from cutting process in adhesive mortar, replacing part of cement. Ehe glass powder is used replacing Portland cement at 10, 15 and 20% by mass. Ehe produced mortars will be evaluated its performance in fresh and hardened states through tests performed in laboratory. Ehe selected feature is indicated by producers of additive and researchers to present good results when used as adhesive mortar.

  5. Characterization of lime mortar additivated with crystallization modifiers

    NARCIS (Netherlands)

    Granneman, S.J.C.; Lubelli, B.; van Hees, R.P.J.

    2018-01-01

    Additivating mortars with crystallization modifiers is a novel approach to mitigate salt crystallization damage in historic masonry. Once verified the effectiveness of crystallization modifiers in bulk solution, the next step consists in verifying whether: (i) modifiers are still effective when

  6. Application of natural seaweed modified mortar for sustainable concrete production

    Science.gov (United States)

    Siddique, M. N. I.; Zularisam, A. W.

    2018-04-01

    The effect of seaweed such as Eucheuma Cottonii (gel) and Gracilaria Sp. modified mortar on the properties of sustainable concrete was investigated. Pre-experiment and main-experiment was conducted to carry out this study. Pre-experiment was conducted to study the compressive strength of the sustainable concrete. The main-experiment studied the compressive and splitting strength. Results showed that seaweed modified mortar yielded satisfactory compressive and splitting strength of 30 MPa and 5 MPa at 28 days.

  7. Study on effective modifiers for damaging salts in mortar

    NARCIS (Netherlands)

    Granneman, S.J.C.; Ruiz-Agudo, E.; Lubelli, B.A.; Hees, R.P.J. van; Rodgriguez-Navarro

    2014-01-01

    The use of crystallization modifiers for the prevention or mitigation of salt crystallization damage has recently received a lot of research interest in the field of building conservation. However, the use of crystallization modifiers mixed in a lime-based mortar, is still a very new field of

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

    KAUST Repository

    Hamzaoui, Rabah; Guessasma, Sofiane; Mecheri, Boubakeur; Eshtiaghi, Amir M.; Bennabi, Abdelkrim

    2014-01-01

    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

  9. Adhesives from modified soy protein

    Science.gov (United States)

    Sun, Susan [Manhattan, KS; Wang, Donghai [Manhattan, KS; Zhong, Zhikai [Manhattan, KS; Yang, Guang [Shanghai, CN

    2008-08-26

    The present invention provides useful adhesive compositions having similar adhesive properties to conventional UF and PPF resins. The compositions generally include a protein portion and modifying ingredient portion selected from the group consisting of carboxyl-containing compounds, aldehyde-containing compounds, epoxy group-containing compounds, and mixtures thereof. The composition is preferably prepared at a pH level at or near the isoelectric point of the protein. In other preferred forms, the adhesive composition includes a protein portion and a carboxyl-containing group portion.

  10. Environmental Factors Affecting the Strength Characteristics of Modified Resin Mortars

    Science.gov (United States)

    Debska, Bernardeta; Licholai, Lech

    2017-12-01

    Resin concretes are composites in which a cement binder has been completely replaced by a synthetic resin. These materials are a good choice for the construction industry, especially in solutions requiring high strength, fast curing and durability. Polymer mortars are mainly used for the manufacture of industrial floors and prefabricated products such as tanks for aggressive chemicals, sewage pipes, or road and bridge drainage systems, as well as for the repair of damaged concrete structures. In all these applications, the strength and high chemical resistance of the applied material solutions are of key importance. It is particularly crucial to obtain information on how resin composites behave when exposed to aggressive agents over extended periods of time. It is also very important to use waste materials in order to obtain resin composites, as these activities are very well inscribed in the idea of environmental protection and meet the criteria of sustainable construction. The mortars described in this article meet the above principles. The article presents how the compressive strength of glycolyzate-modified epoxy mortars, obtained with the use of poly(ethylene terephthalate), changes after they are immersed in 10% sodium chloride solution. Sodium chloride solution was chosen due to the prospective applicability of the tested composites as repair materials used for e.g. bridges or overpasses that are exposed to this salt solution in wintertime. Changes in the properties of the composite samples were monitored over the period of one year. Statistical analysis of the test results was carried out with the use of Statistica programme. The module available in the mentioned program called Nonparametric Statistics - Comparing multiple independent samples made it possible to check the monitoring times during which the compressive strength values differed significantly. The obtained results allowed for determining the equation of the function approximating the course of

  11. Solid state NMR and LVSEM studies on the hardening of latex modified tile mortar systems

    International Nuclear Information System (INIS)

    Rottstegge, J.; Arnold, M.; Herschke, L.; Glasser, G.; Wilhelm, M.; Spiess, H.W.; Hergeth, W.D.

    2005-01-01

    Construction mortars contain a broad variety of both inorganic and organic additives beside the cement powder. Here we present a study of tile mortar systems based on portland cement, quartz, methyl cellulose and different latex additives. As known, the methyl cellulose stabilizes the freshly prepared cement paste, the latex additive enhances final hydrophobicity, flexibility and adhesion. Measurements were performed by solid state nuclear magnetic resonance (NMR) and low voltage scanning electron microscopy (LVSEM) to probe the influence of the latex additives on the hydration, hardening and the final tile mortar properties. While solid state NMR enables monitoring of the bulk composition, scanning electron microscopy affords visualization of particles and textures with respect to their shape and the distribution of the different phases. Within the alkaline cement paste, the poly(vinyl acetate) (VAc)-based latex dispersions stabilized by poly(vinyl alcohol) (PVA) were found to be relatively stable against hydrolysis. The influence of the combined organic additives methyl cellulose, poly(vinyl alcohol) and latexes stabilized by poly(vinyl alcohol) on the final silicate structure of the cement hydration products is small. But even small amounts of additives result in an increased ratio of ettringite to monosulfate within the final hydrated tile mortar as monitored by 27 Al NMR. The latex was found to be adsorbed to the inorganic surfaces, acting as glue to the inorganic components. For similar latex water interfaces built up by poly(vinyl alcohol), a variation in the latex polymer composition results in modified organic textures. In addition to the networks of the inorganic cement and of the latex, there is a weak network build up by thin polymer fibers, most probably originating from poly(vinyl alcohol). Besides the weak network, polymer fibers form well-ordered textures covering inorganic crystals such as portlandite

  12. Fresh and Hardened State of Polymer Modified Concrete and Mortars – A Review

    Directory of Open Access Journals (Sweden)

    Tukimat Nurul Nadrah Aqilah

    2017-01-01

    Full Text Available Polymer modified concrete or mortar is an alternative to the advancement of long serving civil engineering material - mortar and concrete. The excellence and promising benefits of modified composites have led to numerous progressive studies of its application. This paper presented a critical review from previous research on the polymer modified concrete and mortar. Both fresh and hardened state behaviours were reviewed as they are important for the development of excellent engineering material. Most of the applications of polymer modified concrete and mortar can be seen in diverse types of polymer such as latex, epoxy and emulsion. The utilization of each type of polymers resulted in different characteristics of composite concrete or mortar. Such applications have contributed to the improvement in terms of workability and mechanical strength, especially at higher grade of composite strength of concrete material.

  13. Mortar modified with sulfonated polystyrene produced from waste plastic cups

    OpenAIRE

    MOTTA,L. A. C.; VIEIRA,J. G.; OMENA,T. H.; FARIA,F. A. C.; RODRIGUES FILHO,G.; ASSUNÇÃO,R. M. N.

    2016-01-01

    Abstract In this work, we studied the addition of sulfonated polystyrene produced from waste plastic cups as an admixture for mortars. Mortars were analyzed with polystyrene content of 0.0; 0.2; 0.6; 1.0 and 1.4% in relation to the cement mass. The influence of polystyrene on the mortars' properties was evaluated by the consistency index, water retention, water absorption, porosity, elasticity modulus, compressive strength, flexural strength, bond tensile strength and microscopy. The increase...

  14. Impact of Different Binders on the Roughness, Adhesion Strength, and Other Properties of Mortars with Expanded Cork.

    Science.gov (United States)

    Barnat-Hunek, Danuta; Widomski, Marcin K; Szafraniec, Małgorzata; Łagód, Grzegorz

    2018-03-01

    The aim of the research that is presented in this paper was to evaluate the physical and mechanical properties of heat-insulating mortars with expanded cork aggregates and different binders. In this work, the measurements of surface roughness and adhesion strength, supported by determination of basic mechanical and physical parameters, such as density, bulk density, open porosity, total porosity, absorbability, thermal conductivity coefficient, compressive strength, flexural strength, and frost resistance of mortars containing expanded oak cork, were performed. The scanning electron microscope (SEM) investigations demonstrated the microstructure, contact zone, and distribution of pores in the heat-insulating mortars containing expanded cork. The results indicated that the addition of expanded cork and different binders in heat-insulating mortars triggers changes in their roughness and adhesion strength. The SEM research confirmed the very good adhesion of the paste to the cork aggregate.

  15. 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.

  16. Improvement of adhesion performance of mortar-repair interface with inducing crack path into repair

    Directory of Open Access Journals (Sweden)

    A. Satoh

    2015-10-01

    Full Text Available The most important performance for repair materials is adhesion to the substrate. The authors experimentally find out that high modulus fine aggregates in repair material enhance strength of it as well as the strength of the interface repaired with it, compared to the ordinary repair without fine aggregates. This paper elaborates the mechanisms for that with fractographic observation and FEM analysis based on the results of experiment. Also the authors discuss the ways for enhancing the strength and ductility of the repaired mortar

  17. Effect of Gamma Irradiation on Polymer Modified White Sand Cement Mortar Composites

    International Nuclear Information System (INIS)

    Khattab, M.M.

    2012-01-01

    This study focuses on the substitution effect of standard sand of conventional cement mortar made from ordinary Portland cement (OPC) and standard sand (SS) OPC/SS 1:3; by different ratios of white sand (WS) powder to prepare three types of white sand cement mortar designated as 1OPC:2SS:1WS, 1OPC:1SS:2WS and 1OPC:0SS:3WS. The prepared samples were first cured under tap water for different time intervals namely 3, 7, 28 and 90 days. The effect of addition of 10% styrene-acrylic ester (SAE) as well as the effect of different doses of gamma rays (10, 20, 30 and 50 kGy) on the physicomechanical properties of polymer modified white sand cement mortar specimens also discussed. Compression strength test, total porosity and water absorption percentages were measured according to standard specifications. The obtained data indicated that, the cement mortar samples containing different ratios of white sand have lower values of compressive strength as compared to the conventional cement mortar while, the percentages of total porosity and water absorption increased. On the other hand, the polymer modified mortar specimens showed a noticeably enhancement in the physico-mechanical properties under the effect of gamma-radiation than those of untreated samples. These results were confirmed by scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) studies

  18. 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

  19. Studies on physico-chemical and mechanical properties of the irradiated latex modified mortar

    International Nuclear Information System (INIS)

    Yassene, A.A.M.A.

    2009-01-01

    This thesis contains three chapter; chapter(I): Introduction and literature review on:- Introduction to polymer. - Mechanism of polymer-cement co-matrix formation.-Sulphate attack. - Solidification /stabilization of heavy metal in cement mortar. chapter(II): Materials and experimental techniques that include: 1- Preparation of latex polymer films from different polymer latices of styrene butadine rubber latex (SBR), poly (styrene-acrylic ester) latex (SAE) and vinylacetate /versatic -ester copolymer latex (C2A). The effect of γ-irradiation dose on the physico - chemical and mechanical properties of different latex polymer films was studied.2- Preparation of latex polymer-modified cement mortar with different ratios of cement: latex polymer and different curing method.3- Solidification /stabilization (S/S) of electroplating heavy metal precipitate in latex polymer- modified mortar with different cement /electroplating heavy metal sludge ratio. chapter(III) results and discussion

  20. Mechanical strengths of modified PET mortar composites in aggressive MgSO4 medium: ACI & B.S predictions

    OpenAIRE

    Kazi Tani N; Benosman A.S.; Senhadji Y.; Taïbi H.; Mouli M.

    2018-01-01

    Composites mortars based on plastic aggregates are often considered as an innovative materials of the future because of their potential and the advantages they present. In this paper, a comparative study was carried out on the effect of magnesium sulfate MgSO4 (5%) attack on the durability of composite mortars modified by recycled polyethylene terephthalate (PET). Laboratory tests were accomplished on limestone sand and cement mortars where the blended Portland cement was partially replaced b...

  1. 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

  2. Mitigating salt damage in lime-based mortars with mixed-in crystallization modifiers

    NARCIS (Netherlands)

    Granneman, S.J.C.; Lubelli, B.; van Hees, R.P.J.; Quist, W.J.; Granneman, S.J.C.; van Hees, R.P.J.

    2017-01-01

    This paper describes some of the most important results of a four year PhD research on the use of crystallization modifiers mixed in lime mortar to mitigate salt crystallization damage. The research focused on two of the most damaging salts, sodium chloride and sodium sulfate, and suitable

  3. Mitigating salt damage in lime-based mortars with mixed-in crystallization modifiers

    NARCIS (Netherlands)

    Granneman, S.J.C.; Lubelli, B.; van Hees, R.P.J.; Laue, S.

    2017-01-01

    This paper presents the most important results of a research project which
    focused on the use of crystallization modifiers mixed in lime mortar to mitigate
    salt crystallization damage. The research focused on two of the most damaging
    salts, sodium chloride and sodium sulfate, and

  4. Pozzolanic properties of brick powders and their effect on the properties of modified lime mortars

    Czech Academy of Sciences Publication Activity Database

    Navrátilová, Eva; Rovnaníková, P.

    2016-01-01

    Roč. 120, SEP 1 (2016), s. 530-539 ISSN 0950-0618 Institutional support: RVO:68081731 Keywords : materials Science * pozzolanic activity * amorphous phase * modified lime mortars * compressive strength Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.169, year: 2016

  5. The effect of two types of modified Mg-Al hydrotalcites on reinforcement corrosion in cement mortar

    NARCIS (Netherlands)

    Yang, Z.; Polder, R.; Mol, J.M.C.; Andrade, C.

    2017-01-01

    Two modified Mg-Al hydrotalcites (MHTs), (MHT-pAB and MHT-NO2) were incorporated into mortar (with different w/c ratios) in two different ways: (1) as one of the mixing components in bulk mortar; (2) as part of cement paste coating of the reinforcing steel. Accelerated chloride migration, cyclic

  6. Effect of the pre-treatment and the aggregate content on the adhesion strength of repair mortars on Miocene porous limestone

    Science.gov (United States)

    Szemerey-Kiss, Balázs; Török, Ákos

    2016-04-01

    The adhesion between porous limestone and newly prepared repair mortars are crucial in the preservation of historic stone structures. Besides mechanical compatibility other matches such as chemical composition and porosity are also essential, but the current research focuses on the adhesion strength of repair mortars that are used in the restoration of Hungarian porous limestone. 8 mortars (4 commercial and 4 specially prepared) were selected for the tests. Mortars with different amount of aggregate were prepared and caste to stone surface. The stone substrate was highly porous Miocene limestone. The strength was tested by standardized pull-out tests which method is commonly used for concrete testing. The limestone surfaces were either used in their natural conditions or were pre-treated (pre-wetting). The strength of the stone/mortar bond was tested. The failure mechanism was documented and various failure modes were identified. Strength test results suggest that especially pre-treatment influences strongly the pull-out strength at mortar/stone interface. Increasing aggregate content also reduces pull out strength of tested repair mortars, but at various rates depending on the mortar type. The financial support of OTKA post-doctoral grant to BSZK (reference number is: PD 112-955) and National Research, Development and Innovation (NKFI) Fund to ÁT (ref. no. K 116532) are appreciated.

  7. Quartzite mining waste for adhesive mortar production; Rejeitos de mineracao de quartzito para producao de argamassa colante

    Energy Technology Data Exchange (ETDEWEB)

    Dias, L.S.; Mol, R.M.R.; Silva, K.D.C.; Campos, P.A.M.; Mendes, J.C.; Peixoto, R.A.F., E-mail: lumadias_mtpo@hotmail.com [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Laboratorio de Materiais de Construcao Civil; Mendes, A.J.C. [Universidade Federal de Vicosa (UFV), MG (Brazil)

    2016-07-01

    The construction sector is responsible for a high consumption of natural resources. Moreover, the mining industry generates and discard waste improperly in the environment aggravating environmental problems. In order to reduce the natural sand extraction and provide the environmentally correct disposal of mining waste, this work proposes the use of quartzite mining waste to replace natural sand for the production of adhesive mortars. The quartzite mining tailings was chemically characterized using X-ray fluorescence, and morphologically by optical microscopy. In sequence, the mortars were subjected to characterization tests in the fresh state as consistency index, slip, water retention, entrained air content, bulk density and Squeeze Flow. The results were satisfactory, indicating the viability of this material as fine aggregate in total replacement of natural aggregate, allowing the reduction of environmental impacts. (author)

  8. Effect of Modified Rubber Particles Mixing Amount on Properties of Cement Mortar

    Directory of Open Access Journals (Sweden)

    Gang Xue

    2017-01-01

    Full Text Available The crumb rubber cement mortar is prepared by the crumb rubber aggregates in 60 mesh which are modified by 1% polyvinyl alcohol (PVA solution. Some mechanical properties of cement mortar with different crumb rubber aggregate amounts are researched including compressive strength, flexural strength, the ratio of compressive strength to flexural strength, impact resistance, and dry contraction percentage. In our tests, we consider six kinds of the rubber contents, 0%, 7.5%, 15%, 19%, 22.5%, and 30%, respectively. The optimal mixing amount of crumb rubber is determined by measuring three indices, the ratio of compressive strength to flexural strength, impact resistance, and dry contraction percentage. It is shown by test that the ratio of compressive strength to flexural strength is the smallest when the mixing amount of rubber is 19%; meanwhile high impact resistance and rational drying shrinkage are observed. The optimal mixing amount of the rubber particles is 19% determined by this test.

  9. Strong composition dependence of adhesive properties of ultraviolet curing adhesives with modified acrylates

    Science.gov (United States)

    Feng, Yefeng; Li, Yandong; Wang, Fupeng; Peng, Cheng; Xu, Zhichao; Hu, Jianbing

    2018-05-01

    Ultraviolet (UV) curable adhesives have been widely researched in fields of health care and electronic components. UV curing systems with modified acrylic ester prepolymers have been frequently employed. In order to clarify composition dependence of adhesive properties of adhesives containing modified acrylates, in this work, several UV curing adhesives bearing urethane and epoxy acrylates were designed and fabricated. The effects of prepolymer, diluent, feed ratio, initiator and assistant on adhesive performances were investigated. This work might offer a facile route to gain promising high-performance UV curable adhesives with desired adhesive traits through regulating their compositions.

  10. Prepackaged polymer - modified mortar proves effective construction material - field and laboratory observations

    International Nuclear Information System (INIS)

    Afridi, M.U.K.; Khan, A.A.; Rizwan, S.A.; Khaskhali, G.B.

    2005-01-01

    Hi-Bond - prepackaged polymer - modified mortar described in this paper is a revolutionary, multifunctional, high-tech, high performance, sustainable, durability improving group of construction materials with a high cost - benefit ratio. Hi-Bond has been developed by Dadabhoy Construction Technologies (Pvt) Ltd., (DCTL), Karachi, after extensive studies and research both locally and abroad. It can be used in floorings and pavings, integral waterproofing, adhesive applications, protective and decorative coatings, repairs, renovation, rehabilitation, anti corrosive linings, deck coverings, durability and efficiency improvement of canal linings and other hydraulic structures. Hi-Bond has been applied in various projects of national importance with great success for their repairs, renovation and rehabilitation and has also been tested and evaluated at various laboratories with highly encouraging results. Some examples include: (i) earthquake damaged bridge at Lora Nallah on Brewery Road, Quetta, (ii) fire damaged building of the daily Business Recorder House, Karachi, (iii) 200 - year old main dome of the tomb of Hazrat Shah Abdul Latif Bhitai, Bhitshah, Hyderabad, (iv) RCC shell roofs of Mehtab Biscuit and Wafers Factory, Sahiwal, (v) repair of newly built concrete floor on structural slab in a factory building at Karachi, (vi) Mohatta Palace, Clifton, Karachi, (vii) swimming pool at Okara Cantt, and (viii) numerous leaking basements, underground and overhead water reservoirs at and around Karachi including those of new vegetable market on super highway. Building Research Station, Government of the Punjab, Lahore also recommended the use of Hi-Bond in the applications mentioned above after testing and evaluation. The product was found easy in application and offered numerous technical and economical advantages, over conventional products, in variety of applications. It is important to note that shortly after the repairs and renovation of the building of the daily

  11. 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

  12. Development of polymer films by the coalescence of polymer particles in powdered and aqueous polymer-modified mortars

    International Nuclear Information System (INIS)

    Afridi, M.U.K.; Ohama, Y.; Demura, K.; Iqbal, M.Z.

    2003-01-01

    This paper evaluates and compares the coalescence of polymer particles (continuous polymer films formation) in powdered polymer-modified mortars (PPMMs) and aqueous polymer-modified mortars (APMMs). Polymer-modified mortars (PMMs) using various redispersible polymer powders (powdered cement modifiers) and polymer dispersions (aqueous cement modifiers) were prepared by varying the polymer-cement ratio (P/C) and were tested for the characterization of polymer films using a scanning electron microscope (SEM) after curing for 28 days. It is concluded from the test results that mortar constituents of unmodified mortar (UMM) are loosely joined with each other due to the absence of polymer films, thus having a structure with comparatively lower mechanical and durability characteristics. By contrast, mortar constituents in PPMMs and APMMs are compactly joined with each other due to the presence of interweaving polymer films, thereby forming a monolithic structure with improved mechanical and durability characteristics. However, the results make obvious the poor coalescence of polymer particles or development of inferior quality polymers films in PPMMs as compared to that observed in APMMs. Moreover, PPMMs show less uniform distribution of polymer films as compared to that in APMMs. Different powdered cement modifiers have different film-forming capabilities. However, such difference is hardly recognized in aqueous cement modifiers. The polymer films in PPMMs and APMMs may acquire different structures. They may appear as mesh-like, thread-like, rugged, dense or fibrous with fine or rough surfaces. Development of coherent polymer films is not well pronounced at a P/C of 5% in PPMMs, whereas sometimes coherent polymer films are observed at a P/C of 5% in APMMs. At a P/C of 10% or more, fully developed, coherent polymer films are observed in both PPMMs and APMMs

  13. Limiting salt crystallization damage in lime mortar by using crystallization modifiers

    NARCIS (Netherlands)

    Granneman, S.J.C.; Shahidzadeh, N.; Lubelli, B.A.; Hees, R.P.J. van

    2014-01-01

    Salt crystallization is a recurrent cause of damage in porous building materials. Lime-based mortars, which were widely used in construction of ancient masonry, are especially prone to salt damage, due to their low mechanical strength. Existing solutions to tackle salt damage in mortars have been

  14. Adhesive and morphological characteristics of surface chemically modified polytetrafluoroethylene films

    International Nuclear Information System (INIS)

    Hopp, B.; Kresz, N.; Kokavecz, J.; Smausz, T.; Schieferdecker, H.; Doering, A.; Marti, O.; Bor, Z.

    2004-01-01

    In the present paper, we report an experimental determination of adhesive and topographic characteristics of chemically modified surface of polytetrafluoroethylene (PTFE) films. The surface chemistry was modified by ArF excimer laser irradiation in presence of triethylene-tetramine photoreagent. The applied laser fluence was varied in the range of 0.4-9 mJ/cm 2 , and the number of laser pulses incident on the same area was 1500. To detect the changes in the adhesive features of the treated Teflon samples, we measured receding contact angle for distilled water and adhesion strength, respectively. It was found that the receding contact angle decreased from 96 deg. to 30-37 deg. and the adhesion strength of two-component epoxy glue to the treated sample surface increased from 0.03 to 9 MPa in the applied laser fluence range. Additionally, it was demonstrated that the adhesion of human cells to the modified Teflon samples is far better than to the untreated ones. The contact mode and pulsed force mode atomic force microscopic investigations of the treated samples demonstrated that the measured effective contact area of the irradiated films does not differ significantly from that of the original films, but the derived adhesion force is stronger on the modified samples than on the untreated ones. Hence, the increased adhesion of the treated Teflon films is caused by the higher surface energy

  15. 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.

  16. Tensile strength of structural concrete repaired with hi-bond polymer modified mortar

    International Nuclear Information System (INIS)

    Khaskheli, G.B.

    2009-01-01

    Repair of cracks in concrete is often required to save the concrete structures. Appearance of crack in concrete is bound with the tensile strength of concrete. Recently a cement factory in Sindh has launched a HBPMM (Hi-Bond Polymer Modified Mortar) that can be used as a concrete repairing material instead of normal OPC (Ordinary Portland Cement). It is needed to investigate its performance compared to that of OPC. In total 144 concrete cylinders (150x300mm) having strength of 3000 and 5000 psi were manufactured. These cylinders were then splitted by using a UTM (Universal Testing Machine) and their actual tensile strength was obtained. The concrete cylinders were then repaired with different applications of HBPMM and arc. The repaired samples were again splitted at different curing ages (3, 7 and 28 days) and their tensile strength after repair was obtained. The results show that the concrete cylinders repaired with HBPMM could give better tensile strength than that repaired with arc, the tensile strength of concrete cylinders after repair could increase with increase in the application of repairing material i.e. HBPMM or OPC and with curing time, and HBPMM could remain more effective in case of rich mix concrete than that of normal mix concrete. (author)

  17. Study of the adherence between polymer-modified mortars and porcelain stoneware tiles

    Directory of Open Access Journals (Sweden)

    Alessandra Etuko Feuzicana de Souza Almeida

    2005-09-01

    Full Text Available Despite the excellent characteristics of porcelain tiles, their application on building facades requires special attention, since this material differs from conventional ceramics and because facades are exposed to weathering that can damage ceramic revetments. The combination of polymer and silica fume to produce mortars results in excellent properties, which are ideal for repairs and revetments requiring high performance. Such improvements justify its study for the installation of porcelain tiles. This article presents bond strength results for mortars containing different amounts of polymer and silica indicating the applicability of these mortars as a construction material. To complement this study, the interface between the porcelain and the mortars was analyzed by scanning electron microscopy (SEM.

  18. Host factors that modify Plasmodium falciparum adhesion to endothelial receptors.

    Science.gov (United States)

    Mahamar, Almahamoudou; Attaher, Oumar; Swihart, Bruce; Barry, Amadou; Diarra, Bacary S; Kanoute, Moussa B; Cisse, Kadidia B; Dembele, Adama B; Keita, Sekouba; Gamain, Benoît; Gaoussou, Santara; Issiaka, Djibrilla; Dicko, Alassane; Duffy, Patrick E; Fried, Michal

    2017-10-24

    P. falciparum virulence is related to adhesion and sequestration of infected erythrocytes (IE) in deep vascular beds, but the endothelial receptors involved in severe malaria remain unclear. In the largest ever study of clinical isolates, we surveyed adhesion of freshly collected IE from children under 5 years of age in Mali to identify novel vascular receptors, and examined the effects of host age, hemoglobin type, blood group and severe malaria on levels of IE adhesion to a panel of endothelial receptors. Several novel molecules, including integrin α3β1, VE-cadherin, ICAM-2, junctional adhesion molecule-B (JAM-B), laminin, and cellular fibronectin, supported binding of IE from children. Severe malaria was not significantly associated with levels of IE adhesion to any of the 19 receptors. Hemoglobin AC, which reduces severe malaria risk, reduced IE binding to the receptors CD36 and integrin α5β1, while hemoglobin AS did not modify IE adhesion to any receptors. Blood groups A, AB and B significantly reduced IE binding to ICAM-1. Severe malaria risk varies with age, but age significantly impacted the level of IE binding to only a few receptors: IE binding to JAM-B decreased with age, while binding to CD36 and integrin α5β1 significantly increased with age.

  19. Thermogravimetric analyses and mineralogical study of polymer modified mortar with silica fume

    Directory of Open Access Journals (Sweden)

    Alessandra Etuko Feuzicana de Souza Almeida

    2006-09-01

    Full Text Available Mineral and organic additions are often used in mortars to improve their properties. Microstructural investigation concerning the effects of styrene acrylic polymer and silica fume on the mineralogical composition of high-early-strength portland cement pastes after 28 days of hydration are presented in this paper. Thermogravimetry and derivative thermogravimetry were used to study the interaction between polymers and cement, as well as the extent of pozzolanic reaction of the mortars with silica fume. Differential scanning calorimetry and X ray diffraction were used to investigate the cement hydration and the effect of the additions. The results showed that the addition of silica fume and polymer reduces the portlandite formation due to delaying of Portland cement hydration and pozzolanic reaction.

  20. Mechanical and chemical properties of polyvinyl alcohol modified cement mortar with silica fume used as matrix including radioactive waste

    International Nuclear Information System (INIS)

    Dakroury, A. M.

    2007-01-01

    This paper discussed the mechanical and chemical properties of polyvinyl alcohol - modified cement mortar with silica fume to assess the safety for disposal of radioactive waste. The modified cement mortars containing polyvinyl alcohol (PVA) in the presence of 10 % silica fume (SF) .The chemical reaction between polymer and cement - hydrated product were investigated by the Infrared Spectral Technology, Differential Thermal Analysis and X-ray diffraction. The leaching of 137Cs from a waste composite into a surrounding fluid has been studied .The results shown that PVA increases the strength and decreases the porosity. The increase in strength duo to the interaction of PVA with cement , may be forming some new compound that fill the pores or improve the bond between the cement . The pozzolanic reaction of the SF increases the calcium silicate hydrates in the hardening matrix composites. There is distinct change in the refinement of the pore structure in cement composites giving fewer capillary pores and more of the finer gel pores

  1. Synthesis of adhesive radiohardenable resins of the modified polyepoxide type

    International Nuclear Information System (INIS)

    Acquacalda, J.-M.

    1972-01-01

    Eight adhesive radiohardenable resins of the modified epoxide type have been synthesized. Four were obtained from commercial resins: EPON 812, 827, 871 and ARALDITE 106. The synthesis of the four others required the development of analytical techniques to characterize of the reagents beforehand and then to identify the resins themselves. From a study of behavior under irradiation it seems that all the compounds obey a law of acrylic double bond disappearance with the logarithm of irradiation dose for which it is hard to find a detailed theoretical interpretation. The fracture of irradiated adhesive assemblies and their comparison has shown that for acceptable irradiation doses the synthesized resins, especially the product of Bisphenol A condensation on glycidyl acrylate, behave quite as well as polyepoxide resins without possessing the disadvantages inherent to the incorporation of standard chemical hardeners [fr

  2. Synthesis of dextrin-stabilized colloidal silver nanoparticles and their application as modifiers of cement mortar.

    Science.gov (United States)

    Konował, Emilia; Sybis, Marta; Modrzejewska-Sikorska, Anna; Milczarek, Grzegorz

    2017-11-01

    Various commercial dextrins were used as reducing and stabilizing agents for a novel one-step synthesis of silver nanoparticles from ammonia complexes of silver ions. As a result, stable colloids of silver were formed during the reaction with the particle size being the function of the dextrin type. The obtained colloids were characterized by UV-vis spectrophotometry, size distribution (using Non-Invasive Backscatter optics) and transmission electron microscopy (TEM). The achieved results clearly indicate the possibility of low-cost production of large quantities of colloidal silver nanoparticles using materials derived from renewable sources. The resulting silver colloids can be used for different purposes, e.g. as bactericidal agents. Combination of the aforementioned properties of nanosilver particles with plasticizing properties of dextrin enables to obtain cement mortars with increased workability and enhanced compressive strength. Moreover, the obtained material is also characterized by increased immunity to adverse impact of microorganisms. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Drilling mortar

    Energy Technology Data Exchange (ETDEWEB)

    Theodorescu, V; Ditulescu, E

    1979-01-30

    A method is proposed for producing stable drilling mortar from drilled rock which makes it possible to stabilize the walls of the borehole and to maintain producing horizons of oil and gas wells in an undisturbed state. The proposed drilling mortar includes 5-12 wt.-% dry modified calcium lignosulfonate in the form of a solution containing about 30% dry matter with the addition of 0.1 wt.-% anti-foaming agent consisting of C/sub 19/-C/sub 20/ alcohol dissolved in a light petroleum product; cream of milk with about 10 wt.-% Ca(OH)/sub 2/ in a quantity sufficient for reducing the pH value of the ions down to 10.5; sodium chloride in amounts from 5 mg to 100 ml (aqueous phase); ordinarily used agents for ensuring the necessary density, viscosity, and filterability. For example, the preparation of the drilling fluid begins with the processing under laboratory conditions of lignosulfonic pulp obtained in the production of yeast fodder with the following characteristics: specific density, 1.15 kgf/dm/sup 3/; water content, 67% (according to the Dean and Stark method); pH 4.0. In the vessel is placed 1000 cm/sup 3/ lignosulfonic pulp containing 33% dry matter, and the pulp is heated to 90-95/sup 0/C by means of a water bath. To the heated pulp 33 cm/sup 3/ formic acid at a 40-% concentration is added by mixing. The specific temperature of the pulp is maintained in the constant mixing process for two hours. Then the cream of milk containing 10 wt.-% Ca(OH)/sub 2/ is added to raise the pH to 10.5. The cooled product is calcium lignosulfonate. To produce a stable form of the drilling mortar, 750 g clay and 10 g trass gel are added to a vessel containing 1500 cm/sup 3/ fresh water by means of mixing. The resulting dispersed mass remains at rest for 12 hours for purposes of hydration. Then 2 g of an anti-foaming agent dissolved in 6 cm/sup 3/ benzene is introduced to 1000 cm/sup 3/ modified calcium lignosulfonate produced by the above method.

  4. Doxycycline-loaded nanotube-modified adhesives inhibit MMP in a dose-dependent fashion.

    Science.gov (United States)

    Palasuk, Jadesada; Windsor, L Jack; Platt, Jeffrey A; Lvov, Yuri; Geraldeli, Saulo; Bottino, Marco C

    2018-04-01

    This article evaluated the drug loading, release kinetics, and matrix metalloproteinase (MMP) inhibition of doxycycline (DOX) released from DOX-loaded nanotube-modified adhesives. DOX was chosen as the model drug, since it is the only MMP inhibitor approved by the U.S. Food and Drug Administration. Drug loading into the nanotubes was accomplished using DOX solution at distinct concentrations. Increased concentrations of DOX significantly improved the amount of loaded DOX. The modified adhesives were fabricated by incorporating DOX-loaded nanotubes into the adhesive resin of a commercial product. The degree of conversion (DC), Knoop microhardness, DOX release kinetics, antimicrobial, cytocompatibility, and anti-MMP activity of the modified adhesives were investigated. Incorporation of DOX-loaded nanotubes did not compromise DC, Knoop microhardness, or cell compatibility. Higher concentrations of DOX led to an increase in DOX release in a concentration-dependent manner from the modified adhesives. DOX released from the modified adhesives did not inhibit the growth of caries-related bacteria, but more importantly, it did inhibit MMP-1 activity. The loading of DOX into the nanotube-modified adhesives did not compromise the physicochemical properties of the adhesives and the released levels of DOX were able to inhibit MMP activity without cytotoxicity. Doxycycline released from the nanotube-modified adhesives inhibited MMP activity in a concentration-dependent fashion. Therefore, the proposed nanotube-modified adhesive may hold clinical potential as a strategy to preserve resin/dentin bond stability.

  5. Reducing composite restoration polymerization shrinkage stress through resin modified glass-ionomer based adhesives.

    Science.gov (United States)

    Naoum, S J; Mutzelburg, P R; Shumack, T G; Thode, Djg; Martin, F E; Ellakwa, A E

    2015-12-01

    The aim of this study was to determine whether employing resin modified glass-ionomer based adhesives can reduce polymerization contraction stress generated at the interface of restorative composite adhesive systems. Five resin based adhesives (G Bond, Optibond-All-in-One, Optibond-Solo, Optibond-XTR and Scotchbond-Universal) and two resin modified glass-ionomer based adhesives (Riva Bond-LC, Fuji Bond-LC) were analysed. Each adhesive was applied to bond restorative composite Filtek-Z250 to opposing acrylic rods secured within a universal testing machine. Stress developed at the interface of each adhesive-restorative composite system (n = 5) was calculated at 5-minute intervals over 6 hours. The resin based adhesive-restorative composite systems (RBA-RCS) demonstrated similar interface stress profiles over 6 hours; initial rapid contraction stress development (0-300 seconds) followed by continued contraction stress development ≤0.02MPa/s (300 seconds - 6 hours). The interface stress profile of the resin modified glass-ionomer based adhesive-restorative composite systems (RMGIBA-RCS) differed substantially to the RBA-RCS in several ways. Firstly, during 0-300 seconds the rate of contraction stress development at the interface of the RMGIBA-RCS was significantly (p adhesives can significantly reduce the magnitude and rate of polymerization contraction stress developed at the interface of adhesive-restorative composite systems. © 2015 Australian Dental Association.

  6. Potential dependent adhesion forces on bare and underpotential deposition modified electrode surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Serafin, J.M.; Hsieh, S.J.; Monahan, J.; Gewirth, A.A. [Univ. of Illinois, Urbana, IL (United States)

    1998-12-03

    Adhesion force measurements are used to determine the potential dependence of the force of adhesion between a Si{sub 3}N{sub 4} cantilever and a Au(111) surface modified by the underpotential deposition (upd) of Bi or Cu in acid solution or by oxide formation. The measured work of adhesion is near zero for most of the potential region examined in Bi upd but rises after the formation of a full Bi monolayer. The work of adhesion is high at positive potentials for Cu upd but then decreases as the Cu partial and full monolayers are formed. The work of adhesion is low in the oxide region on Au(111) but rises following the sulfate disordering transition at 1.1 V vs NHE. These results are interpreted in terms of the degree of solvent order on the electrode surface.

  7. Creep simulation of adhesively bonded joints using modified generalized time hardening model

    Energy Technology Data Exchange (ETDEWEB)

    Sadigh, Mohammad Ali Saeimi [Azarbaijan Shahid Madani University, Tabriz (Iran, Islamic Republic of)

    2016-04-15

    Creep behavior of double lap adhesively bonded joints was investigated using experimental tests and numerical analysis. Firstly, uniaxial creep tests were carried out to obtain the creep characteristics and constitutive parameters of the adhesive at different stress and temperature levels. Generalized time hardening model was used to predict the creep behavior of the adhesive. This model was modified to simulate the creep behavior at different stress and temperature levels. Secondly, the developed model was used to simulate the creep behavior of bonded joints using finite element based numerical analysis. Creep deformations of the joints were measured experimentally and good agreement was observed in comparison with the results obtained using numerical simulation. Afterward, stress redistribution due to the creep along the adhesively bonded joint was obtained numerically. It was observed that temperature level had a significant effect on the stress redistribution along the adhesive thickness.

  8. Modified silyl-terminated polyether polymer blends with bisphenol A diglycidyl ether epoxy for adhesive applications

    International Nuclear Information System (INIS)

    Bitenieks, J; Meri, R Merijs; Zicans, J; Berzins, R; Umbraško, J; Rekners, U

    2016-01-01

    Modified silyl-terminated polyether polymer (MS Polymer) was blended with bisphenol A diglycidyl ether (DGEBPA) epoxy at MS Polymer/epoxy ratio from 30/70 to 70/30. MS Polymer/epoxy systems were examined for two-component adhesive formulation with additional fillers. Applicability of the MS Polymer/epoxy system at the ratio of the components 60/40 is demonstrated for the development of adhesive formulation. Rheological analysis of the components A and B shows suitable viscosity values for development of two- component adhesives formulation. Curing dynamics as well as tensile stress-strain properties and Shore A hardness of the chosen adhesive formulation are reasonable for the development of MS Polymer/epoxy type adhesive. (paper)

  9. Adhesion

    Science.gov (United States)

    ... Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Adhesion URL of this page: //medlineplus.gov/ency/article/001493.htm Adhesion To use the sharing features on this page, please enable JavaScript. Adhesions are bands of scar-like tissue that form between two ...

  10. Bio-active molecules modified surfaces enhanced mesenchymal stem cell adhesion and proliferation

    International Nuclear Information System (INIS)

    Mobasseri, Rezvan; Tian, Lingling; Soleimani, Masoud; Ramakrishna, Seeram; Naderi-Manesh, Hossein

    2017-01-01

    Surface modification of the substrate as a component of in vitro cell culture and tissue engineering, using bio-active molecules including extracellular matrix (ECM) proteins or peptides derived ECM proteins can modulate the surface properties and thereby induce the desired signaling pathways in cells. The aim of this study was to evaluate the behavior of human bone marrow mesenchymal stem cells (hBM-MSCs) on glass substrates modified with fibronectin (Fn), collagen (Coll), RGD peptides (RGD) and designed peptide (R-pept) as bio-active molecules. The glass coverslips were coated with fibronectin, collagen, RGD peptide and R-peptide. Bone marrow mesenchymal stem cells were cultured on different substrates and the adhesion behavior in early incubation times was investigated using scanning electron microscopy (SEM) and confocal microscopy. The MTT assay was performed to evaluate the effect of different bio-active molecules on MSCs proliferation rate during 24 and 72 h. Formation of filopodia and focal adhesion (FA) complexes, two steps of cell adhesion process, were observed in MSCs cultured on bio-active molecules modified coverslips, specifically in Fn coated and R-pept coated groups. SEM image showed well adhesion pattern for MSCs cultured on Fn and R-pept after 2 h incubation, while the shape of cells cultured on Coll and RGD substrates indicated that they might experience stress condition in early hours of culture. Investigation of adhesion behavior, as well as proliferation pattern, suggests R-peptide as a promising bio-active molecule to be used for surface modification of substrate in supporting and inducing cell adhesion and proliferation. - Highlights: • Bioactive molecules modified surface is a strategy to design biomimicry scaffold. • Bi-functional Tat-derived peptide (R-pept) enhanced MSCs adhesion and proliferation. • R-pept showed similar influences to fibronectin on FA formation and attachment.

  11. Nano-modified adhesive by graphene: the single lap-joint case

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, Almir; Cruz, Diego Thadeu Lopes da; Avila, Antonio Ferreira, E-mail: aavila@netuno.lcc.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Mecanica

    2013-11-01

    This paper addresses the performance study on, low viscosity, nano-modified adhesives by graphene. For achieving this goal, single-lap joints following ASTM D 5868-01 were manufactured and tested. X-ray diffraction, scanning electron microscopy and nanoindentation were employed for graphene based nanostructures characterization. The increase on joint strength was around 57% when compared against the control group. Furthermore, all failures for the nano-modified adhesive were cohesive failure for the carbon fibre/epoxy composites indicating that the adhesive was tested. X-ray diffractions signatures indicate formation of nano-structures with 17-19 nm diameters. Moreover, nanoindentation tests revealed a homogeneous dispersion of graphene. (author)

  12. In vitro evaluation of tissue adhesives composed of hydrophobically modified gelatins and disuccinimidyl tartrate

    Directory of Open Access Journals (Sweden)

    Miyuki Matsuda

    2012-01-01

    Full Text Available The effect of the hydrophobic group content in gelatin on the bonding strength of novel tissue–penetrating tissue adhesives was evaluated. The hydrophobic groups introduced into gelatin were the saturated hexanoyl, palmitoyl, and stearoyl groups, and the unsaturated oleoyl group. A collagen casing was employed as an adherend to model soft tissue for the in vitro determination of bonding strength of tissue adhesives composed of various hydrophobically modified gelatins and disuccinimidyl tartrate. The adhesive composed of stearoyl-modified gelatin (7.4% stearoyl; 10Ste and disuccinimidyl tartrate showed the highest bonding strength. The bonding strength of the adhesives decreased as the degree of substitution of the hydrophobic groups increased. Cell culture experiments demonstrated that fluorescein isothiocyanate-labeled 10Ste was integrated onto the surface of smooth muscle cells and showed no cytotoxicity. These results suggest that 10Ste interacted with the hydrophobic domains of collagen casings, such as hydrophobic amino acid residues and cell membranes. Therefore, 10Ste–disuccinimidyl tartrate is a promising adhesive for use in aortic dissection.

  13. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces.

    Science.gov (United States)

    Jogikalmath, G; Stuart, J K; Pungor, A; Hlady, V

    1999-08-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface more uniform. The subsequent hydrolysis of the terminal epoxide groups resulted in a larger surface heterogeneity which was modeled by two populations of the terminal hydroxyl groups, each with its own distribution of adhesion forces and force variance. The activation of the hydroxyls with carbonyldiimmidazole (CDI) healed the surface and lowered its adhesion, however, the force variance remained rather large. Finally, the grafting of the α,ω-diamino poly(ethyleneoxide) chains to the CDI-activated glass largely eliminated adhesion except at a few discrete regions. The adhesion on the PEO grafted layer followed the Poisson distribution of the pull-off forces. With the exception of the glass surface, a correlation between the water contact angles and the mean pull-off forces measured with the Si(3)N(4) tip surfaces was found for all modified glass surfaces.

  14. Effects of delayed polymerization time and bracket manipulation on orthodontic resin modified glass ionomer adhesive

    Science.gov (United States)

    Gilbert, Danielle Wiggins

    This study examined the effect of varying delayed polymerization times in combination with bracket manipulation on shear bond strength (SBS), degree of conversion (DC), and adhesive remnant index (ARI) score when using a resin modified glass ionomer (RMGI) adhesive. Specimens were divided into three groups of clinically relevant delay times (0.5, 2, and 4-min) to simulate the delay that frequently occurs between bracket placement and manipulation and subsequent light curing. Based on an analysis of variance (alpha=.05), the SBS was not significantly different between the three groups. While one of the goals of this study was to be the first study to quantify DC of RMGI using Raman microspectroscopy, several challenges, including weak peak signal with and without fluorescence, were encountered and as a result, DC could not be determined. A significant difference (pbracket with increasing delay time. A Spearman correlation between SBS and ARI indicated no positive association between SBS and ARI measures across delay times. The results of this study suggest that clinically relevant delay times of 0.5, 2, and 4-min do not negatively impact the SBS of a RMGI adhesive. However, with increasing delay time, the results suggest that more adhesive might remain on the bracket during debonding. With more adhesive remaining on the bracket, this could be beneficial in that less adhesive needs to be removed from enamel by grinding at the time of bracket removal when orthodontic treatment is completed.

  15. Study on surface adhesion of Plasma modified Polytetrafluoroethylene hollow fiber membrane

    Science.gov (United States)

    Chen, Jiangrong; Zhang, Huifeng; Liu, Guochang; Guo, Chungang; Lv, Jinglie; Zhangb, Yushan

    2018-01-01

    Polytetrafluoroethylene (PTFE) is popular membrane material because of its excellent thermal stability, chemical stability and mechanical stability. However, the low surface energy and non-sticky property of PTFE present challenges for modification. In the present study, plasma treatment was performed to improve the surface adhesion of PTFE hollow fiber membrane. The effect of discharge voltage, treatment time on the adhesion of PTFE hollow fiber membrane was symmetrically evaluated. Results showed that the plasma treatment method contributed to improve the surface activity and roughness of PTFE hollow fiber membrane, and the adhesion strength depend significantly on discharge voltage, which was beneficial to seepage pressure of PTFE hollow fiber membrane module. The adhesion strength of PTFE membrane by plasma treated at 220V for 3min reached as high as 86.2 N, far surpassing the adhesion strength 12.7 N of pristine membrane. Furthermore, improvement of content of free radical and composition analysis changes of the plasma modified PTFE membrane were investigated. The seepage pressure of PTFE membrane by plasma treated at 220V for 3min was 0.375 MPa, which means that the plasma treatment is an effective technique to improve the adhesion strength of membrane.

  16. 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

  17. Chitosan scaffold modified with D-(+) raffinose and enriched with thiol-modified gelatin for improved osteoblast adhesion

    International Nuclear Information System (INIS)

    Galli, C; Parisi, L; Smerieri, A; Lumetti, S; Manfredi, E; Macaluso, G M; Elviri, L; Bianchera, A; Bettini, R; Lagonegro, P

    2016-01-01

    The aim of the present study was to investigate whether chitosan-based scaffolds modified with D-(+) raffinose and enriched with thiol-modified gelatin could selectively improve osteoblast adhesion and proliferation. 2, 3 and 4.5% chitosan films were prepared. Chitosan suitability for tissue engineering was confirmed by protein adsorption assay. Scaffolds were incubated with a 2.5 mg ml −1 BSA solution and the decrease of protein content in the supernatants was measured by spectrophotometry. Chitosan films were then enriched with thiol-modified gelatin and their ability to bind BSA was also measured. Then, 2% chitosan discs with or without thiol-modified gelatin were used as culture substrates for MC3T3-E1 cells. After 72 h cells were stained with trypan blue or with calcein AM and propidium iodide for morphology, viability and proliferation assays. Moreover, cell viability was measured at 48, 72, 96 and 168 h to obtain a growth curve. Chitosan films efficiently bound and retained BSA proportionally to the concentration of chitosan discs. The amount of protein retained was higher on chitosan enriched with thiol-modified gelatin. Moreover, chitosan discs allowed the adhesion and the viability of cells, but inhibited their proliferation. The functionalization of chitosan with thiol-modified gelatin enhanced cell spreading and proliferation. Our data confirm that chitosan is a suitable material for tissue engineering. Moreover, our data show that the enrichment of chitosan with thiol-modified gelatin enhances its biological properties. (paper)

  18. Preparing high-adhesion silver coating on APTMS modified polyethylene with excellent anti-bacterial performance

    Science.gov (United States)

    Li, Wenfei; Chen, Yunxiang; Wu, Song; Zhang, Jian; Wang, Hao; Zeng, Dawen; Xie, Changsheng

    2018-04-01

    Silver coating as a broad-spectrum antimicrobial agent was considered to alleviate the inflammation caused by intrauterine device (IUD) in endometrium. In this work, to avoid the damage of silver coating and ensure its antibacterial properties, 3-aminopropyltrimethoxysilane (APTMS) was introduced to modify the polyethylene (PE) substrate for the purpose of improving the adhesion of the silver coating. From the 90° peel test, it could be found that the adhesive strength of silver coating on the APTMS modified PE substrate was nearly 23 times stronger than the silver coating on substrate without surface modification. The dramatically enhanced adhesive strength could be attributed to the formation of continuous chemical bonds between the silver coatings and substrates after surface modification, which had been confirmed by the XPS. Moreover, the standard antibacterial test revealed that the silver coated samples against Staphylococcus aureus (S. aureus) exhibit excellent antibacterial efficacy. Considering the largely enhanced adhesion and the effective antibacterial property, it is reasonable to believe that the silver coating could be considered as a potential candidate for the antibacterial agent in IUD.

  19. Tracking metal ions with polypyrrole thin films adhesively bonded to diazonium-modified flexible ITO electrodes.

    Science.gov (United States)

    Lo, Momath; Diaw, Abdou K D; Gningue-Sall, Diariatou; Aaron, Jean-Jacques; Oturan, Mehmet A; Chehimi, Mohamed M

    2018-05-09

    Adhesively bonded polypyrrole thin films doped with benzene sulfonic acid (BSA) were electrodeposited on aminobenzenediazonium-modified flexible ITO electrodes and further employed for the detection of Pb 2+ , Cu 2+ , and Cd 2+ metal ions in aqueous medium. The aminophenyl (AP) adhesive layer was grafted to ITO by electroreduction of the in situ generated parent diazonium compound. Polypyrrole (PPy) thin films exhibited remarkable adhesion to aminophenyl (ITO-AP). The strongly adherent polypyrrole films exhibited excellent electroactivity in the doped state with BSA which itself served to chelate the metal ions in aqueous medium. The surface of the resulting, modified flexible electrode was characterized by XPS, SEM, and electrochemical methods. The ITO-AP-PPy electrodes were then used for the simultaneous detection of Cu 2+ , Cd 2+ , and Pb 2+ by differential pulse voltammetry (DPV). The detection limits were 11.1, 8.95, and 0.99 nM for Cu 2+ , Cd 2+ , and Pb 2+ , respectively. In addition, the modified electrodes displayed a good reproducibility, making them suitable for the determination of heavy metals in real wastewater samples.

  20. Cell Adhesion and Proliferation on Sulfonated and Non-Modified Chitosan Films.

    Science.gov (United States)

    Martínez-Campos, Enrique; Civantos, Ana; Redondo, Juan Alfonso; Guzmán, Rodrigo; Pérez-Perrino, Mónica; Gallardo, Alberto; Ramos, Viviana; Aranaz, Inmaculada

    2017-05-01

    Three types of chitosan-based films have been prepared and evaluated: a non-modified chitosan film bearing cationizable aliphatic amines and two films made of N-sulfopropyl chitosan derivatives bearing both aliphatic amines and negative sulfonate groups at different ratios. Cell adhesion and proliferation on chitosan films of C2C12 pre-myoblastic cells and B16 cells as tumoral model have been tested. A differential cell behavior has been observed on chitosan films due to their different surface modification. B16 cells have shown lower vinculin expression when cultured on sulfonated chitosan films. This study shows how the interaction among cells and material surface can be modulated by physicochemical characteristics of the biomaterial surface, altering tumoral cell adhesion and proliferation processes.

  1. Cell adhesion on polytetrafluoroethylene modified by UV-irradiation in an ammonia atmosphere

    Czech Academy of Sciences Publication Activity Database

    Heitz, J.; Švorčík, V.; Bačáková, Lucie; Ročková, K.; Ratajová, E.; Gumpenberger, T.; Bäuerle, D.; Dvořánková, B.; Kahr, H.; Graz, I.; Romanin, C.

    67A, č. 1 (2003), s. 130-137 ISSN 0021-9304 R&D Projects: GA AV ČR IAA5011301 Grant - others:FWF(AT) P14476-TPH; GA FRVŠ(CZ) 283-2002-G1; CZ-AT Scientific-Technical Cooperation(CZ) 2002-7 Institutional research plan: CEZ:AV0Z5011922 Keywords : cell adhesion * UV-modified polymer * amino acid grafting Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.397, year: 2003

  2. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces

    OpenAIRE

    Jogikalmath, G.; Stuart, J.K.; Pungor, A.; Hlady, V.

    1999-01-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface mo...

  3. An in vitro bacterial adhesion assessment of surface-modified medical-grade PVC.

    Science.gov (United States)

    Asadinezhad, Ahmad; Novák, Igor; Lehocký, Marián; Sedlarík, Vladimir; Vesel, Alenka; Junkar, Ita; Sáha, Petr; Chodák, Ivan

    2010-06-01

    Medical-grade polyvinyl chloride was surface modified by a multistep physicochemical approach to improve bacterial adhesion prevention properties. This was fulfilled via surface activation by diffuse coplanar surface barrier discharge plasma followed by radical graft copolymerization of acrylic acid through surface-initiated pathway to render a structured high density brush. Three known antibacterial agents, bronopol, benzalkonium chloride, and chlorhexidine, were then individually coated onto functionalized surface to induce biological properties. Various modern surface probe techniques were employed to explore the effects of the modification steps. In vitro bacterial adhesion and biofilm formation assay was performed. Escherichia coli strain was found to be more susceptible to modifications rather than Staphylococcus aureus as up to 85% reduction in adherence degree of the former was observed upon treating with above antibacterial agents, while only chlorhexidine could retard the adhesion of the latter by 50%. Also, plasma treated and graft copolymerized samples were remarkably effective to diminish the adherence of E. coli. Copyright 2010 Elsevier B.V. All rights reserved.

  4. Improvement of thermal stability of UV curable pressure sensitive adhesive by surface modified silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Beili; Ryu, Chong-Min; Kim, Hyung-Il, E-mail: hikim@cnu.ac.kr

    2013-11-01

    Highlights: • Silica nanoparticles were modified to carry the vinyl groups for photo-crosslinking. • Acrylic copolymer was modified to have the vinyl groups for photo-crosslinking. • Strong and extensive interfacial bondings were formed between polymer and silica. • Thermal stability of PSA was improved by forming nanocomposite with modified silica. -- Abstract: Pressure sensitive adhesives (PSAs) with higher thermal stability were successfully prepared by forming composite with the silica nanoparticles modified via reaction with 3-methacryloxypropyltrimethoxysilane. The acrylic copolymer was synthesized as a base resin for PSAs by solution polymerization of 2-EHA, EA, and AA with AIBN as an initiator. The acrylic copolymer was further modified with GMA to have the vinyl groups available for UV curing. The peel strength decreased with the increase of gel content which was dependent on both silica content and UV dose. Thermal stability of the composite PSAs was improved noticeably with increasing silica content and UV dose mainly due to the strong and extensive interfacial bonding between the organic polymer matrix and silica.

  5. Multilayer Choline Phosphate Molecule Modified Surface with Enhanced Cell Adhesion but Resistance to Protein Adsorption.

    Science.gov (United States)

    Chen, Xingyu; Yang, Ming; Liu, Botao; Li, Zhiqiang; Tan, Hong; Li, Jianshu

    2017-08-22

    Choline phosphate (CP), which is a new zwitterionic molecule, and has the reverse order of phosphate choline (PC) and could bind to the cell membrane though the unique CP-PC interaction. Here we modified a glass surface with multilayer CP molecules using surface-initiated atom-transfer radical polymerization (SI-ATRP) and the ring-opening method. Polymeric brushes of (dimethylamino)ethyl methacrylate (DMAEMA) were synthesized by SI-ATRP from the glass surface. Then the grafted PDMAEMA brushes were used to introduce CP groups to fabricate the multilayer CP molecule modified surface. The protein adsorption experiment and cell culture test were used to evaluate the biocompatibility of the modified surfaces by using human umbilical veinendothelial cells (HUVECs). The protein adsorption results demonstrated that the multilayer CP molecule decorated surface could prevent the adsorption of fibrinogen and serum protein. The adhesion and proliferation of cells were improved significantly on the multilayer CP molecule modified surface. Therefore, the biocompatibility of the material surface could be improved by the modified multilayer CP molecule, which exhibits great potential for biomedical applications, e.g., scaffolds in tissue engineering.

  6. Improvement of copper plating adhesion on silane modified PET film by ultrasonic-assisted electroless deposition

    International Nuclear Information System (INIS)

    Lu Yinxiang

    2010-01-01

    Copper thin film on silane modified poly(ethylene terephthalate) (PET) substrate was fabricated by ultrasonic-assisted electroless deposition. The composition and topography of copper plating PET films were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. Peel adhesion strength, as high as 16.7 N/cm, was achieved for the planting copper layer to the modified PET substrate with ultrasonic-assisted deposition; however, a relative low value as 11.9 N/cm was obtained for the sample without ultrasonic vibration by the same measurement. The electrical conductivity of Cu film was changed from 7.9 x 10 4 to 2.1 x 10 5 S/cm by using ultrasonic technique. Ultrasonic operation has the significant merits of fast deposition and formation of good membranes for electroless deposition of Cu on PET film.

  7. Shear bond strength evaluation of resin composite to resin-modified glass-ionomer cement using three different resin adhesives vs. glass-ionomer based adhesive

    Directory of Open Access Journals (Sweden)

    Mostafa Sadeghi

    2015-12-01

    Full Text Available Background: The clinical success of sandwich technique depends on the strength of resin-modified glass ionomer cement (RMGIC bonding to both dentin and resin composite. Therefore, the shear bond strength (SBS of resin composite bonded to RMGIC utilizing different resin adhesives versus a GIC-based adhesive was compared. Materials and methods: In this in vitro study, 84 holes (5×2 mm were prepared in acrylic blocks, randomly divided into seven groups (n=12 and filled with RMGIC (Light-Cured Universal Restorative, GC. In the Group I; no adhesive was applied on the RMGIC. In the Group II, non-etched and Group III was etched with phosphoric acid. In groups II and III, after rinsing, etch-and-rinse adhesive (OptiBond Solo Plus; in the Group IV; a two-step self-etch adhesive (OptiBond XTR and in Group V; a one-step self-etch (OptiBond All-in-One were applied on the cement surfaces. Group VI; a GIC-based adhesive (Fuji Bond LC was painted over the cement surface and cured. Group VII; the GIC-based adhesive was brushed over RMGIC followed by the placement of resin composite and co-cured. Afterward; resin composite (Point 4 cylinders were placed on the treated cement surfaces. The specimens were placed in 100% humidity at 37 ± 1°C and thermo cycled. The shear bond test was performed at a cross-head speed of 1 mm/min and calculated in MPa; the specimens were examined to determine mode of failure. The results were analyzed using one-way ANOVA and Tukey test. Results: The maximum (24.62±3.70 MPa and minimum (18.15±3.38 MPa SBS mean values were recorded for OptiBond XTR adhesive and the control group, respectively. The pairwise comparisons showed no significant differences between the groups that bonded with different adhesives. The adhesive failure was the most common failure mode observed. Conclusion: This study suggests that GIC-based adhesive could be applied over RMGIC as co-cure technique for sandwich restorations in lieu of employing the resin

  8. Bacterial adhesion studies on titanium, titanium nitride and modified hydroxyapatite thin films

    International Nuclear Information System (INIS)

    Jeyachandran, Y.L.; Venkatachalam, S.; Karunagaran, B.; Narayandass, Sa.K.; Mangalaraj, D.; Bao, C.Y.; Zhang, C.L.

    2007-01-01

    A qualitative study on adhesion of the oral bacteria Porphyromonas gingivalis on titanium (Ti), titanium nitride (TiN), fluorine modified hydroxyapatite (FHA) and zinc modified FHA (Zn-FHA) thin films is investigated. Ti and TiN thin films were deposited by DC magnetron sputtering and hydroxyapatite-based films were prepared by solgel method. The crystalline structure, optical characteristics, chemical composition and surface topography of the films were studied by XRD, optical transmission, XPS, EDAX and AFM measurements. The predominant crystallite orientation in the Ti and TiN films was along (002) and (111) of hcp and cubic structures, respectively. The Ti : O : N composition ratio in the surface of the Ti and TiN films was found to be 7 : 21 : 1 and 3 : 8 : 2, respectively. The atomic concentration ratio (Zn + Ca) / P in Zn-FHA film was found to be 1.74 whereby the Zn replaced 3.2% of Ca. The rough surface feature in modified HA films was clearly observed in the SEM images and the surface roughness (rms) of Ti and TiN films was 2.49 and 3.5 nm, respectively, as observed using AFM. The film samples were sterilized, treated in the bacteria culture medium, processed and analyzed using SEM. Surface roughness of the films was found to have least influence on the bacterial adhesion. More bacteria were observed on the TiN film with oxide nitride surface layer and less number of adhered bacteria was noticed on the Ti film with native surface oxide layer and on Zn-FHA film

  9. Bacterial adhesion studies on titanium, titanium nitride and modified hydroxyapatite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jeyachandran, Y L [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Venkatachalam, S [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Karunagaran, B [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Narayandass, Sa K [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Mangalaraj, D [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Bao, C Y [West China College of Stomatology, Sichuan University, Chengdu 610041 (China); Zhang, C L [West China College of Stomatology, Sichuan University, Chengdu 610041 (China)

    2007-01-15

    A qualitative study on adhesion of the oral bacteria Porphyromonas gingivalis on titanium (Ti), titanium nitride (TiN), fluorine modified hydroxyapatite (FHA) and zinc modified FHA (Zn-FHA) thin films is investigated. Ti and TiN thin films were deposited by DC magnetron sputtering and hydroxyapatite-based films were prepared by solgel method. The crystalline structure, optical characteristics, chemical composition and surface topography of the films were studied by XRD, optical transmission, XPS, EDAX and AFM measurements. The predominant crystallite orientation in the Ti and TiN films was along (002) and (111) of hcp and cubic structures, respectively. The Ti : O : N composition ratio in the surface of the Ti and TiN films was found to be 7 : 21 : 1 and 3 : 8 : 2, respectively. The atomic concentration ratio (Zn + Ca) / P in Zn-FHA film was found to be 1.74 whereby the Zn replaced 3.2% of Ca. The rough surface feature in modified HA films was clearly observed in the SEM images and the surface roughness (rms) of Ti and TiN films was 2.49 and 3.5 nm, respectively, as observed using AFM. The film samples were sterilized, treated in the bacteria culture medium, processed and analyzed using SEM. Surface roughness of the films was found to have least influence on the bacterial adhesion. More bacteria were observed on the TiN film with oxide nitride surface layer and less number of adhered bacteria was noticed on the Ti film with native surface oxide layer and on Zn-FHA film.

  10. Characterization of antibacterial and adhesion properties of chitosan-modified glass ionomer cement.

    Science.gov (United States)

    Ibrahim, Marrwa A; Neo, Jennifer; Esguerra, Roxanna J; Fawzy, Amr S

    2015-10-01

    The aim is to investigate the effect of modifying the liquid phase of a conventional glass ionomer restorative material with different chitosan volume contents on the antibacterial properties and adhesion to dentin. The liquids of commercially available restorative glass ionomer cements (GIC) were modified with chitosan (CH) solutions at different volume contents (5%, 10%, 25%, and 50%). The GIC powders were mixed with the unmodified and the CH-modified liquids at the desired powder/liquid (P/L) ratio. For the characterization of the antibacterial properties, Streptococcus mutans biofilms were formed on GIC discs and characterized by scanning electron microscope (SEM), confocal microscopy, colony forming unit (CFU) count, and cell viability assay (MTS). The unmodified and CH-modified GICs were bonded to dentin surfaces and the micro-tensile bond strength (µTBs) was evaluated and the interface was investigated by SEM. Modification with CH solutions enhanced the antibacterial properties against S. mutans in terms of resistance to biofilm formation, CFU count, and MTS assay. Generally, significant improvement in the antibacterial properties was found with the increase in the CH volume content. Modification with 25% and 50% CH adversely affected the µTBs with predominant cohesive failure in the GIC. However, no difference was found between the control and the 5% and 10% CH-modified specimens. Incorporation of acidic solutions of chitosan in the polyacrylic acid liquid of GIC at v/v ratios of 5-10% improved the antibacterial properties of conventional glass ionomer cement against S. mutans without adversely affecting its bonding to dentin surface. © The Author(s) 2015.

  11. Relationship of Adhesive, Contact and Electret Properties of PTFE Modified by DC Discharge

    Science.gov (United States)

    Yablokov, M.; Piskarev, M.; Gilman, A.; Kechek'yan, A.; Kuznetsov, A.

    2018-02-01

    The relationship between the contact, adhesive and electret properties of PTFE films modified by direct current glow discharge has been studied. The film samples of 40 μm thickness were placed at the anode and cathode and treated in the air as a working gas. The contact properties of polymer surface were characterized by the values of deionized water contact angle. The peel strength was determined using T-peel test for the Scotch®810/PTFE film contact. The electret potential was measured by the compensation technique using dynamic capacitor, and from the measured potential value the effective surface charge density was calculated. It has been found that there is an undoubted correlation between the change in the value of water contact angle, the peel strength of the DC discharge-treated film, and the magnitude of the effective surface charge.

  12. Mortars for 3D printing

    Directory of Open Access Journals (Sweden)

    Demyanenko Olga

    2018-01-01

    Full Text Available The paper is aimed at developing scientifically proven compositions of mortars for 3D printing modified by a peat-based admixture with improved operational characteristics. The paper outlines the results of experimental research on hardened cement paste and concrete mixture with the use of modifying admixture MT-600 (thermally modified peat. It is found that strength of hardened cement paste increases at early age when using finely dispersed admixtures, which is the key factor for formation of construction and technical specifications of concrete for 3D printing technologies. The composition of new formations of hardened cement paste modified by MT-600 admixture were obtained, which enabled to suggest the possibility of their physico-chemical interaction while hardening.

  13. Bacterial adhesion to orthopaedic implant materials and a novel oxygen plasma modified PEEK surface

    NARCIS (Netherlands)

    Rochford, E. T. J.; Poulsson, A. H. C.; Salavarrieta Varela, J.; Lezuo, P.; Richards, R. G.; Moriarty, T. F.

    2014-01-01

    Despite extensive use of polyetheretherketone (PEEK) in biomedical applications, information about bacterial adhesion to this biomaterial is limited. This study investigated Staphylococcus aureus and Staphylococcus epidermidis adhesion to injection moulded and machined PEEK OPTIMA (R) using a

  14. Protein Modifiers Generally Provide Limited Improvement in Wood Bond Strength of Soy Flour Adhesives

    Science.gov (United States)

    Charles R. Frihart; Linda Lorenz

    2013-01-01

    Soy flour adhesives using a polyamidoamine-epichlorohydrin (PAE) polymeric coreactant are used increasingly as wood adhesives for interior products. Although these adhesives give good performance, higher bond strength under wet conditions is desirable. Wet strength is important for accelerated tests involving the internal forces generated by the swelling of wood and...

  15. Natural radioactivity levels and danger ratio in cements, concretes and mortars used in construction

    International Nuclear Information System (INIS)

    Meneses, J.; Pacheco, C.; Avila, J. M.; Miro, C.

    2010-01-01

    We have determined the natural radiation level in three types of adhesive cements, five types of concrete and two types of mortars of different strength normally used in the construction field. Of these materials, both concrete and mortars were prepared in our laboratories, cements the contrary were of a commercial nature.

  16. Adhesion and removal kinetics of Bacillus cereus biofilms on Ni-PTFE modified stainless steel.

    Science.gov (United States)

    Huang, Kang; McLandsborough, Lynne A; Goddard, Julie M

    2016-01-01

    Biofilm control remains a challenge to food safety. A well-studied non-fouling coating involves codeposition of polytetrafluoroethylene (PTFE) during electroless plating. This coating has been reported to reduce foulant build-up during pasteurization, but opportunities remain in demonstrating its efficacy in inhibiting biofilm formation. Herein, the initial adhesion, biofilm formation, and removal kinetics of Bacillus cereus on Ni-PTFE-modified stainless steel (SS) are characterized. Coatings lowered the surface energy of SS and reduced biofilm formation by > 2 log CFU cm(-2). Characterization of the kinetics of biofilm removal during cleaning demonstrated improved cleanability on the Ni-PTFE coated steel. There was no evidence of biofilm after cleaning by either solution on the Ni-PTFE coated steel, whereas more than 3 log and 1 log CFU cm(-2) of bacteria remained on the native steel after cleaning with water and an alkaline cleaner, respectively. This work demonstrates the potential application of Ni-PTFE non-fouling coatings on SS to improve food safety by reducing biofilm formation and improving the cleaning efficiency of food processing equipment.

  17. Using Mortar Mixing Pump for Magnesia Mortars Preparing and Transporting

    Science.gov (United States)

    Kiyanets, A. V.

    2017-11-01

    The article is devoted to the problem of preparation and transportation of magnesia mortars with the help of screw mortar mixing pumps. The urgency of the wide use of mortars on magnesia binders (Sorel’s cement) in construction is substantiated due to their high characteristics: strength, hardening speed, wear resistance, possibility of using organic and mineral aggregates, ecological purity and economic efficiency. The necessity for the development of a technique for calculating the main parameters of a mortar mixing pump for its application in the technology of preparation and transportation of magnesia mortars is demonstrated. The analysis of various types of modern mortar mixing pumps is given. The conclusions are drawn about the advantages and disadvantages of standard schemes. The description of the experiment for determination of the productivity of a mortar mixing pump is described depending on the plasticity (mobility) of the used magnesia mortar. The graph and description of the mathematical dependency of the productivity of the mortar mixing pump on the magnesia mortar plasticity are given. On the basis of the obtained dependency, as well as the already known formulas given in the article, a new method is proposed for calculating the main parameters of the screw mortar mixing pump in preparation and transportation of magnesia mortar: productivity, feed range, supply pressure, drive power.

  18. Vascular smooth muscle cell stiffness and adhesion to collagen I modified by vasoactive agonists.

    Directory of Open Access Journals (Sweden)

    Zhongkui Hong

    Full Text Available In vascular smooth muscle cells (VSMCs integrin-mediated adhesion to extracellular matrix (ECM proteins play important roles in sustaining vascular tone and resistance. The main goal of this study was to determine whether VSMCs adhesion to type I collagen (COL-I was altered in parallel with the changes in the VSMCs contractile state induced by vasoconstrictors and vasodilators. VSMCs were isolated from rat cremaster skeletal muscle arterioles and maintained in primary culture without passage. Cell adhesion and cell E-modulus were assessed using atomic force microscopy (AFM by repetitive nano-indentation of the AFM probe on the cell surface at 0.1 Hz sampling frequency and 3200 nm Z-piezo travelling distance (approach and retraction. AFM probes were tipped with a 5 μm diameter microbead functionalized with COL-I (1 mg\\ml. Results showed that the vasoconstrictor angiotensin II (ANG-II; 10-6 significantly increased (p<0.05 VSMC E-modulus and adhesion probability to COL-I by approximately 35% and 33%, respectively. In contrast, the vasodilator adenosine (ADO; 10-4 significantly decreased (p<0.05 VSMC E-modulus and adhesion probability by approximately -33% and -17%, respectively. Similarly, the NO donor (PANOate, 10-6 M, a potent vasodilator, also significantly decreased (p<0.05 the VSMC E-modulus and COL-I adhesion probability by -38% and -35%, respectively. These observations support the hypothesis that integrin-mediated VSMC adhesion to the ECM protein COL-I is dynamically regulated in parallel with VSMC contractile activation. These data suggest that the signal transduction pathways modulating VSMC contractile activation and relaxation, in addition to ECM adhesion, interact during regulation of contractile state.

  19. Improved mortar setup technique

    CSIR Research Space (South Africa)

    De Villiers, D

    2008-10-01

    Full Text Available bearing sensor. This concept focuses directly on one of the most cumbersome aspects of a mortar set-up, namely the use of aiming posts. The prismatic mirror and bearing dials is described as well as the required setup procedures. The measurement...

  20. Novel epoxy-silicone thermolytic transparent packaging adhesives chemical modified by ZnO nanowires for HB LEDs

    International Nuclear Information System (INIS)

    He Ying; Wang Junan; Pei Changlong; Song Jizhong; Zhu Di; Chen Jie

    2010-01-01

    A novel high transparent thermolytic epoxy-silicone for high-brightness light-emitting diode (HB-LED) is introduced, which was synthesized by polymerization using silicone matrix via diglycidyl ether bisphenol-A epoxy resin (DGEBA) as reinforcing agent, and filling ZnO nanowires to modify thermal conductivity and control refractive index of the hybrid material. The interactions of ZnO nanowires with polymers are mediated by the ligands attached to the nanoparticles. Thus, the ligands markedly influence the properties of ZnO nanowires/epoxy-silicone composites. The refractive indices of the prepared hybrid adhesives can be tuned by the ZnO nanowires from 1.4711 to 1.5605. Light transmittance can be increased by 20% from 80 to 95%. The thermal conductivity of the transparent packaging adhesives is 0.89-0.90 W/mK.

  1. Study on the Soy Protein-Based Wood Adhesive Modified by Hydroxymethyl Phenol

    Directory of Open Access Journals (Sweden)

    Hong Lei

    2016-07-01

    Full Text Available To explain the reason why using phenol-formaldehyde (PF resin improves the water resistance of soy-based adhesive, the performance of soy-based adhesive cross-linked with hydroxymethyl phenol (HPF and the reaction between HPF and a common dipeptide N-(2-l-alanyl-l-glutamine (AG being used as a model compound were studied in this paper. The DSC and DMA results indicated the reaction between HPF and soy-based adhesive. The soy-based adhesive cross-linked with HPF cured at a lower temperature than the adhesive without HPF. The former showed better mechanical performance and heat resistance than the latter. The ESI-MS, FT-IR and 13C-NMR results proved the reaction between HPF and AG. Because of the existence of branched ether groups in the 13C-NMR results of HPF/AG, the reaction between HPF and AG might mainly happened between hydroxymethyl groups and amino groups under a basic condition.

  2. Domain decomposition methods for mortar finite elements

    Energy Technology Data Exchange (ETDEWEB)

    Widlund, O.

    1996-12-31

    In the last few years, domain decomposition methods, previously developed and tested for standard finite element methods and elliptic problems, have been extended and modified to work for mortar and other nonconforming finite element methods. A survey will be given of work carried out jointly with Yves Achdou, Mario Casarin, Maksymilian Dryja and Yvon Maday. Results on the p- and h-p-version finite elements will also be discussed.

  3. Microleakage after Thermocycling of Three Self-Etch Adhesives under Resin-Modified Glass-Ionomer Cement Restorations

    Directory of Open Access Journals (Sweden)

    Sabine O. Geerts

    2010-01-01

    Full Text Available This study was designed to evaluate microleakage that appeared on Resin-Modified Glass-Ionomer Cement (RMGIC restorations. Sixty class V cavities (h×w×l=2mm×2mm×3mm were cut on thirty extracted third molars, which were randomly allocated to three experimental groups. All the buccal cavities were pretreated with polyacrylic acid, whereas the lingual cavities were treated with three one-step Self-Etch adhesives, respectively, Xeno III (Dentsply Detrey GmbH, Konstanz, Germany, iBond exp (Heraeus Kulzer gmbH & Co. KG, Hanau, Germany, and Adper Prompt-L-Pop (3M ESPE AG, Dental products Seefeld, Germany. All cavities were completely filled with RMGIC, teeth were thermocycled for 800 cycles, and leakage was evaluated. Results were expressed as means ± standard deviations (SDs. Microleakage scores were analysed by means of generalized linear mixed models (GLMMs assuming an ordinal logistic link function. All results were considered to be significant at the 5% critical level (<.05. The results showed that bonding RMGIC to dentin with a Self-Etch adhesive rather than using polyacrylic acid did not influence microleakage scores (=.091, except for one tested Self-Etch adhesive, namely, Xeno III (<.0001. Nevertheless, our results did not show any significant difference between the three tested Self-Etch adhesive systems. In conclusion, the pretreatment of dentin with Self-Etch adhesive system, before RMGIC filling, seems to be an alternative to the conventional Dentin Conditioner for the clinicians as suggested by our results (thermocycling and others (microtensile tests.

  4. 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. 

  5. Thermomechanical and adhesive properties of radiation-modified polymer composites for thermosetting products

    International Nuclear Information System (INIS)

    Kalkis, V.; Maksimov, R.D.; Kalnins, M.; Zicans, J.; Bocoka, T.; Revjakin, O.

    2000-01-01

    The gamma-irradiated blends of polyethylene (PE) with ethylene / propylene / diene copolymer (Epdm) and thermotropic liquid crystalline polymer (LCP) are investigated. The radiation dose absorbed does not exceed 150 kGy (10 kGy=1 Mrad). It is shown that the even small amounts of LCP added to PE improve the mechanical and operational properties of composites and the thermosetting products made of them. The temperature dependences of the elastics modulus, tension diagrams at a temperature above the PE melting point, and recovery curves of the oriented specimens are presented. The kinetics of thermorelaxation and residual setting stresses upon isometric heating and cooling of the previously oriented composites is studied. The data on the influence of LCP on the adhesion interaction of the blend with steel are obtained. The features of thermomechanical and adhesive properties are discussed and the results of morphological and calorimetric tests are given. (author)

  6. Influence of surfaces modified with biomimetic extracellular matrices on adhesion and proliferation of mesenchymal stem cells and osteosarcoma cells.

    Science.gov (United States)

    Cai, Rong; Kawazoe, Naoki; Chen, Guoping

    2015-02-01

    Preparation of surfaces modified with biomimetic extracellular matrices (ECMs) is important for investigation of the interaction between ECMs and cells. In the present study, surfaces modified with ECMs from normal somatic cells, stem cells and tumor cells were prepared by cell culture method. The ECMs derived from bone marrow-derived mesenchymal stem cells (MSCs), dermal fibroblasts (FBs), osteoblasts (OBs) and MG63 osteosarcoma cells were deposited on the surfaces of cell-culture polystyrene plates (TCPS). The ECMs from different cell types had different compositions. The effects of the ECM-deposited surfaces on the adhesion, spreading and proliferation of MSCs and MG63 human osteosarcoma cells were dependent on the type of both ECMs and cells. The surfaces deposited with ECMs from MSCs, FBs and OBs promoted cell adhesion more strongly than surfaces deposited with ECMs from MG63 cells and TCPS. Compared to TCPS, the ECM-deposited surfaces promoted proliferation of MSCs while they inhibited the proliferation of MG63 cells. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. The long term effect on cement mortar by admixture of spray drying absorption products

    International Nuclear Information System (INIS)

    Jeppesen, K.G.

    1988-01-01

    Preliminary investigations have shown that the substitutions of up to 10% fly ash (FA), with spray drying absorption products (SDA), in cement mortars (cement: 80% rapid portland cement (RPC), 10-20% FA, 0-10% SDA) results in low early strength of the same magnitude as in mortar with 80% RPC + 20% FA. Use of the modified instructions for preparation of mortar prisms containing SDA resulted in satisfactory early strengths. A series of mortar prisms with increasing content of SDA (x% RPC, (100-x)% SDA in cements; 0 80% cannot be stored wet. The effects on mortars of the individual constituents of the SDA-products are studied by XRD, development in strength and density. Fragments of 2 year old SDA containing cement mortars and SDA containing concrete from a parking place have been studied

  8. Moisture transport properties of mortar and mortar joint: A NMR study

    OpenAIRE

    Brocken, H.J.P.; Adant, O.C.G.; Pel, L.

    1997-01-01

    The moisture transport in mortar and mortar joint often is an important parameter in degeneration of brick masonry and other block constructions. In this study, the influence of single additives on the moisture transport properties of mortar is investigated. Due to water extraction during brick laying, curing conditions of mortar in mortar joint differ from curing conditions of separately cured mortar. Consequently, the moisture transport properties of mortar joint differ. In addition to the ...

  9. Moisture transport properties of mortar and mortar joint: a NMR study

    OpenAIRE

    Brocken, H.J.P.; Adan, O.C.G.; Pel, L.

    1997-01-01

    The moisture transport in mortar and mortar joint often is an important parameter in degeneration of brick masonry and other block constructions. In this study, the influence of single additives on the moisture transport properties of mortar is investigated. Due to water extraction during brick laying, curing conditions of mortar in mortar joint differ from curing conditions of separately cured mortar. Consequently, the moisture transport properties of mortar joint differ. In addition to the ...

  10. Bond durability of adhesives containing modified-monomer with/without-fluoride after aging in artificial saliva and under intrapulpal pressure simulation.

    Science.gov (United States)

    El-Deeb, H A; Al Sherbiney, H H; Mobarak, E H

    2013-01-01

    To evaluate the dentin bond strength durability of adhesives containing modified-monomer with/without-fluoride after storage in artificial saliva and under intrapulpal pressure simulation (IPPS). The occlusal enamel of 48 freshly extracted teeth was trimmed to expose midcoronal dentin. Roots were sectioned to expose the pulp chamber and to connect the specimens to the pulpal-pressure assembly. Specimens were assigned into four groups (n=12) according to adhesive system utilized: a two-step etch-and-rinse adhesive system (SB, Adper Single Bond 2, 3M ESPE), a two-step self-etch adhesive system (CSE, Clearfil SE Bond, Kuraray Medical Inc), and two single-step self-etch adhesives with the same modified monomer (bis-acrylamide)-one with fluoride (AOF, AdheSE One F, Ivoclar-Vivadent) and the other without (AO, AdheSE One, Ivoclar-Vivadent). Bonding was carried out while the specimens were subjected to 15-mm Hg IPPS. Resin composite (Valux Plus, 3M ESPE) buildups were made. After curing, specimens were aged in artificial saliva and under 20-mm Hg IPPS at 37°C in a specially constructed incubator either for 24 hours or six months prior to testing. Bonded specimens (n=6/group) were sectioned into sticks (n=24/group) with a cross section of 0.9 ± 0.01 mm(2) and subjected to microtensile bond strength (μTBS) testing using a universal testing machine. Data were statistically analyzed using two-way analysis of variance (ANOVA) with repeated measures, one-way ANOVA tests, and a t-test (partificial saliva and under IPPS, yet these values remained significantly higher than those for the other two adhesives with modified monomers. There was no significant difference in the bond strength values between fluoride-containing and fluoride-free self-etch adhesive systems (AOF and AO) after 24 hours or six months. Modes of failure were mainly adhesive and mixed. Based on the results of this study, 1) Fluoride addition did not affect dentin bond durability; and 2) despite the fact that

  11. Estimation of Frost Resistance of the Tile Adhesive on a Cement Based with Application of Amorphous Aluminosilicates as a Modifying Additive

    Science.gov (United States)

    Ivanovna Loganina, Valentina; Vladimirovna Zhegera, Christina

    2017-10-01

    In the article given information on the possibility of using amorphous aluminosilicates as a modifying additive in the offered tile cement adhesive. In the article, the data on the preparation of an additive based on amorphous aluminosilicates, on its microstructure and chemical composition. Presented information on the change in the porosity of cement stone when introduced of amorphous aluminosilicates in the his composition. The formulation of a dry building mix on a cement base is proposed with use of an additive based on amorphous aluminosilicates as a modifying additive. Recipe of dry adhesive mixes include Portland cement M400, mineral aggregate in proportion fraction 0.63-0.315:0.315-0.14 respectively 80:20 (%) and filling density of 1538.2 kg/m3, a plasticizer Kratasol, redispersible powder Neolith P4400 and amorphous alumnosilicates. The developed formulation can be used as a tile adhesive for finishing walls of buildings and structure with tiles. Presented results of the evaluation of frost resistance of adhesives based on cement with using of amorphous aluminosilicates as a modifying additive. Installed the mark on the frost resistance of tile glue and frost resistance of the contact zone of adhesive. Established, that the adhesive layer based on developed formulation dry mixture is crack-resistant and frost-resistant for conditions city Penza and dry humidity zone - zone 3 and climatic subarea IIB (accordance with Building codes and regulations 23-01-99Ȋ) cities Russia’s.

  12. Modification of Lime Mortars with Synthesized Aluminosilicates

    Science.gov (United States)

    Loganina, Valentina I.; Sadovnikova, Marija E.; Jezierski, Walery; Małaszkiewicz, Dorota

    2017-10-01

    The increasing attention for restoration of buildings of historical and architectural importance has increased the interest for lime-based binders, which could be applied for manufacturing repair mortars and plasters compatible with historical heritage. Different additives, admixtures or fibers may be incorporated to improve mechanical and thermal features of such materials. In this study synthesized aluminosilicates (SA) were applied as an additive for lime mortar. The technology of synthesis consisted in the deposition of aluminosilicates from a sodium liquid glass by the aluminum sulphate Al2(SO4)3. The goal of this investigation was developing a new method of aluminosilicates synthesis from a sodium liquid glass and using this new material as a component for a lime mortar. Aluminosilicates were precipitated from the solution of aluminum sulphate Al2(SO)3 and sodium silicate. SA were then used as an additive to calcareous compositions and their influence was tested. Mortars were prepared with commercial air lime and siliceous river sand. Air lime binder was replaced by 5 and 10 wt.% of SA. Calcareous composition specimens were formed at water/lime ratio 1.0. The following analyses were made: grain size distribution of SA, X-ray diffraction analysis (XRD), sorption properties, plastic strength and compressive strength of lime mortars. XRD pattern of the SA shows the presence of thenardite, gibbsite and amorphous phase represented by aggregate of nano-size cristobalite-like crystallites. Application of SA leads to increase of compressive strength after 90 days of hardening by 28% and 53% at SA content 5 and 10% respectively comparing to specimens without this additive. Contents of chemically bound lime in the reference specimens after 28 days of hardening in air-dry conditions was 46.5%, while in specimens modified with SA contained 50.0-55.3% of bound lime depending on filtrate pH. This testifies to high activity of calcareous composition. The new blended lime

  13. Influence of laser surface modifying of polyethylene terephthalate on fibroblast cell adhesion

    International Nuclear Information System (INIS)

    Mirzadeh, H.; Dadsetan, M.

    2003-01-01

    Attempts have been made to evaluate the changes in physical and chemical properties of the polyethylene terephthalate (PET) surface due to laser irradiation. These changes have been investigated from viewpoints of microstructuring and its effect on fibroblast cell behavior. The surfaces of PET were irradiated using CO 2 and KrF excimer pulsed laser. The changes were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and contact angle measurements. The data from ATR-FTIR spectra showed that the crystallinity in the surface region decreased due to the CO 2 and excimer laser irradiation. SEM observations showed that specific microstructures were created on the PET surface due to laser irradiation. In order to study biocompatibility and cell behavior, we utilized standard in vitro L929-fibroblast cell culture system. Fibroblast cell adhesion and spreading were significantly correlated to the morphology and wettability of the laser irradiated PET surface

  14. Adhesive Bioactive Coatings Inspired by Sea Life.

    Science.gov (United States)

    Rego, Sónia J; Vale, Ana C; Luz, Gisela M; Mano, João F; Alves, Natália M

    2016-01-19

    Inspired by nature, in particular by the marine mussels adhesive proteins (MAPs) and by the tough brick-and-mortar nacre-like structure, novel multilayered films are prepared in the present work. Organic-inorganic multilayered films, with an architecture similar to nacre based on bioactive glass nanoparticles (BG), chitosan, and hyaluronic acid modified with catechol groups, which are the main components responsible for the outstanding adhesion in MAPs, are developed for the first time. The biomimetic conjugate is prepared by carbodiimide chemistry and analyzed by ultraviolet-visible spectrophotometry. The buildup of the multilayered films is monitored with a quartz crystal microbalance with dissipation monitoring, and their topography is characterized by atomic force microscopy. The mechanical properties reveal that the films containing catechol groups and BG present an enhanced adhesion. Moreover, the bioactivity of the films upon immersion in a simulated body fluid solution is evaluated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. It was found that the constructed films promote the formation of bonelike apatite in vitro. Such multifunctional mussel inspired LbL films, which combine enhanced adhesion and bioactivity, could be potentially used as coatings of a variety of implants for orthopedic applications.

  15. Durability of air lime mortar

    DEFF Research Database (Denmark)

    Nielsen, Anders

    2016-01-01

    This contribution deals with the physical and chemical reasons why pure air lime mortars used in masonry of burned bricks exposed to outdoor climate have shown to be durable from the Middle Ages to our days. This sounds strange in modern times where pure air lime mortars are regarded as weak...... materials, which are omitted from standards for new masonry buildings, where use of hydraulic binders is prescribed. The reasons for the durability seam to be two: 1. The old mortars have high lime contents. 2. The carbonation process creates a pore structure with a fine pored outer layer and coarser pores...

  16. The relationship between cellular adhesion and surface roughness in polystyrene modified by microwave plasma radiation

    Directory of Open Access Journals (Sweden)

    Biazar E

    2011-03-01

    Full Text Available Esmaeil Biazar1, Majid Heidari2, Azadeh Asefnezhad2, Naser Montazeri11Department of Chemistry, Islamic Azad University, Tonekabon Branch, Mazandaran; 2Department of Biomaterial Engineering, Faculty of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IranBackground: Surface modification of medical polymers can improve biocompatibility. Pure polystyrene is hydrophobic and cannot provide a suitable environment for cell cultures. The conventional method for surface modification of polystyrene is treatment with plasma. In this study, conventional polystyrene was exposed to microwave plasma treatment with oxygen and argon gases for 30, 60, and 180 seconds.Methods and results: Attenuated total reflection Fourier transform infrared spectra investigations of irradiated samples indicated clearly the presence of functional groups. Atomic force microscopic images of samples irradiated with inert and active gases indicated nanometric surface topography. Samples irradiated with oxygen plasma showed more roughness (31 nm compared with those irradiated with inert plasma (16 nm at 180 seconds. Surface roughness increased with increasing duration of exposure, which could be due to reduction of the contact angle of samples irradiated with oxygen plasma. Contact angle analysis showed reduction in samples irradiated with inert plasma. Samples irradiated with oxygen plasma showed a lower contact angle compared with those irradiated by argon plasma.Conclusion: Cellular investigations with unrestricted somatic stem cells showed better adhesion, cell growth, and proliferation for samples radiated by oxygen plasma with increasing duration of exposure than those of normal samples.Keywords: surface topography, polystyrene, plasma treatment, argon, oxygen

  17. Comparative of fibroblast and osteoblast cells adhesion on surface modified nanofibrous substrates based on polycaprolactone

    OpenAIRE

    Sharifi, Fereshteh; Irani, Shiva; Zandi, Mojgan; Soleimani, Masoud; Atyabi, Seyed Mohammad

    2016-01-01

    One of the determinant factors for successful bioengineering is to achieve appropriate nano-topography and three-dimensional substrate. In this research, polycaprolactone (PCL) nano-fibrous mat with different roughness modified with O2 plasma was fabricated via electrospinning. The purpose of this study was to evaluate the effect of plasma modification along with surface nano-topography of mats on the quality of human fibroblast (HDFs) and osteoblast cells (OSTs)-substrate interaction. Surfac...

  18. Mortar fights acid corrosion

    Energy Technology Data Exchange (ETDEWEB)

    1982-05-14

    The burning of coal or oil to produce heat required to operate a power boiler also generates a severe corrosion problem within the interior of the duct and stacks used to emit the flue gas into the atmosphere. How can concrete and steel be protected from the effects of acid attack, when the acids are carried in a gas form, or come into direct contact with the steel or concrete from spillage or immersion conditions. Industry in North America has found that the solution to this problem is to build an outside concrete column, in this case of Portland cement, and inside that column, build a totally independent brick liner bonded with Sauereisen mortar.

  19. The relationship between cellular adhesion and surface roughness for polyurethane modified by microwave plasma radiation

    Directory of Open Access Journals (Sweden)

    Heidari S

    2011-04-01

    Full Text Available Saeed Heidari Keshel1, S Neda Kh Azhdadi2, Azadeh Asefnezhad2, Mohammad Sadraeian3, Mohamad Montazeri4, Esmaeil Biazar51Stem Cell Preparation Unit, Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences; 2Department of Biomaterial Engineering, Faculty of Biomedical Engineering, Science and Research Branch - Islamic Azad University; 3Young Researchers Club, Islamic Azad University, North Tehran Branch, Tehran; 4Faculty of Medical Sciences, Babol University of Medical Sciences, Babol; 5Department of Chemistry, Islamic Azad University, Tonekabon, IranAbstract: Surface modification of medical polymers is carried out to improve biocompatibility. In this study, conventional polyurethane was exposed to microwave plasma treatment with oxygen and argon gases for 30 seconds and 60 seconds. Attenuated total reflection Fourier transform infrared spectra investigations of irradiated samples indicated the presence of functional groups. Atomic force microscope images of samples irradiated with inert and active gases indicated the nanometric topography of the sample surfaces. Samples irradiated by oxygen plasma indicated high roughness compared with those irradiated by inert plasma for the different lengths of time. In addition, surface roughness increased with time, which can be due to a reduction of contact angle of samples irradiated by oxygen plasma. Contact angle analysis indicated a reduction in samples irradiated with both types of plasma. However, samples irradiated with oxygen plasma indicated lower contact angle compared with those irradiated by argon plasma. Cellular investigations with unrestricted somatic stem cells showed better adhesion, cell growth, and proliferation among samples radiated by oxygen plasma for longer than for normal samples.Keywords: surface topography, polyurethane, plasma treatment, cellular investigation

  20. Copper tailings in stucco mortars

    Directory of Open Access Journals (Sweden)

    Osvaldo Pavez

    Full Text Available Abstract This investigation addressed the evaluation of the use of copper tailings in the construction industry in order to reduce the impact on the environment. The evaluation was performed by a technical comparison between stucco mortars prepared with crushed conventional sand and with copper tailings sand. The best results were achieved with the stucco mortars containing tailings. The tailings presented a fine particles size distribution curve different from that suggested by the standard. The values of compressive strength, retentivity, and adherence in the stucco mortars prepared with copper tailings were much higher than those obtained with crushed sand. According to the results from this study, it can be concluded that the preparation of stucco mortars using copper tailings replacing conventional sand is a technically feasible alternative for the construction industry, presenting the benefit of mitigating the impact of disposal to the environment.

  1. Method of producing grouting mortar

    Energy Technology Data Exchange (ETDEWEB)

    Shelomov, I K; Alchina, S I; Dizer, E I; Gruzdeva, G A; Nikitinskii, V I; Sabirzyanov, A K

    1980-10-07

    A method of producing grouting mortar by mixing the cement with an aqueous salt solution is proposed. So as to increase the quality of the mortar through an acceleration of the time for hardening, the mixture is prepared in two stages, in the first of which 20-30% of the entire cement batch hardens, and in the second of which the remainder of the cement hardens; 1-3-% of an aqueous salt solution is used in quantities of 0.5/1 wt.-% of weight of the cement. The use of this method of producing grouting mortar helps to increase the flexural strength of the cement brick up to 50% after two days ageing by comparison with the strength of cement brick produced from grouting mortar by ordinary methods utilizing identical quantities of the initial components (cement, water, chloride).

  2. Effect of Polysiloxanes on Roughness and Durability of Basalt Fibres–Reinforced Cement Mortar

    Directory of Open Access Journals (Sweden)

    Danuta Barnat-Hunek

    2018-04-01

    Full Text Available The influence of roughness and the way it affects the adhesion properties and surface free energy (SFE of polysiloxanes hydrophobised basalt fibres–reinforced cement mortars were determined in this article. The physical properties of mortars were investigated in the experimental part, which also explored the impact of hydrophobisation and basalt fibres (BF addition on SFE, frost resistance, contact angle (CA, and roughness. A device capable of calculating all parameters was used to indicate the surface roughness and 3D topography. Prior to and after conducting surface and weight hydrophobisation, the contact angle of mortars was specified. Subsequently, it was used for carrying out SFE calculation by means of Neumann’s method, enabling us to characterize the adhesion properties and wettability of mortars. The research indicated that the surface roughness was substantially decreased, in turn raising the frost resistance. The corrosion resistance drops when the surface roughness, water absorption, and number of fibres in the mortar increase. The SEM images presenting the structure of polysiloxane coating and mortars were provided.

  3. 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.

  4. NMR relaxometry study of plaster mortar with polymer additives

    Science.gov (United States)

    Jumate, E.; Moldovan, D.; Fechete, R.; Manea, D.

    2013-11-01

    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 T2 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 T2 distributions. These can be associated with the proton bounded chemical or physical to the mortar minerals characterized by a short T2 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 T2 relaxation rates corresponding to the bound water.

  5. NMR relaxometry study of plaster mortar with polymer additives

    International Nuclear Information System (INIS)

    Jumate, E.; Manea, D.; Moldovan, D.; Fechete, R.

    2013-01-01

    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 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 2 distributions. These can be associated with the proton bounded chemical or physical to the mortar minerals characterized by a short T 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 2 relaxation rates corresponding to the bound water

  6. Calcium Sulfoaluminate, Geopolymeric, and Cementitious Mortars for Structural Applications

    Directory of Open Access Journals (Sweden)

    Alessandra Mobili

    2017-09-01

    Full Text Available This paper deals with the study of calcium sulfoaluminate (CSA and geopolymeric (GEO binders as alternatives to ordinary Portland cement (OPC for the production of more environmentally-friendly construction materials. For this reason, three types of mortar with the same mechanical strength class (R3 ≥ 25 MPa, according to EN 1504-3 were tested and compared; they were based on CSA cement, an alkaline activated coal fly ash, and OPC. Firstly, binder pastes were prepared and their hydration was studied by means of X-ray diffraction (XRD and differential thermal-thermogravimetric (DT-TG analyses. Afterwards, mortars were compared in terms of workability, dynamic modulus of elasticity, adhesion to red clay bricks, free and restrained drying shrinkage, water vapor permeability, capillary water absorption, and resistance to sulfate attack. DT-TG and XRD analyses evidenced the main reactive phases of the investigated binders involved in the hydration reactions. Moreover, the sulfoaluminate mortar showed the smallest free shrinkage and the highest restrained shrinkage, mainly due to its high dynamic modulus of elasticity. The pore size distribution of geopolymeric mortar was responsible for the lowest capillary water absorption at short times and for the highest permeability to water vapor and the greatest resistance to sulfate attack.

  7. Improved mortar set-up technique

    CSIR Research Space (South Africa)

    De Villiers, D

    2010-05-01

    Full Text Available -up Technique Presented at the Mortar Systems Conference By D de Villiers May 2009 Mobile Mortars Slide 2 © CSIR 2008 www.csir.co.za Mobile Mortars Slide 3 © CSIR 2008 www.csir.co.za Mobile Mortars Slide 4... © CSIR 2008 www.csir.co.za Mortar Tests Slide 5 © CSIR 2008 www.csir.co.za Mortar Tests Slide 6 © CSIR 2008 www.csir.co.za Electronic Sensors Slide 7 © CSIR 2008...

  8. Comparative of fibroblast and osteoblast cells adhesion on surface modified nanofibrous substrates based on polycaprolactone.

    Science.gov (United States)

    Sharifi, Fereshteh; Irani, Shiva; Zandi, Mojgan; Soleimani, Masoud; Atyabi, Seyed Mohammad

    2016-12-01

    One of the determinant factors for successful bioengineering is to achieve appropriate nano-topography and three-dimensional substrate. In this research, polycaprolactone (PCL) nano-fibrous mat with different roughness modified with O 2 plasma was fabricated via electrospinning. The purpose of this study was to evaluate the effect of plasma modification along with surface nano-topography of mats on the quality of human fibroblast (HDFs) and osteoblast cells (OSTs)-substrate interaction. Surface properties were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle, Fourier-transformation infrared spectroscopy. We evaluated mechanical properties of fabricated mats by tensile test. The viability and proliferation of HDFs and OSTs on the substrates were followed by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT). Mineralization of the substrate was determined by alizarin red staining method and calcium content of OSTs was determined by calcium content kit. Cells morphology was studied by SEM analysis. The results revealed that the plasma-treated electrospun nano-fibrous substrate with higher roughness was an excellent designed substrate. A bioactive topography for stimulating proliferation of HDFs and OSTs is to accelerate the latter's differentiation time. Therefore, the PCL substrate with high density and major nano-topography were considered as a bio-functional and elegant bio-substrate for tissue regeneration applications.

  9. [Effects of sintered bone modified with surface mineralization/P24 peptide composite biomaterial on the adhesion, proliferation and osteodifferentiation of MC3T3-E1 cells].

    Science.gov (United States)

    Li, Jingfeng; Zheng, Qixin; Guo, Xiaodong; Chen, Liaobin

    2014-10-01

    In the present research, the effects of sintered bone modified with surface mineralization/P24 peptide composite biomaterials on the adhesion, proliferation and osteodifferentiation of MC3T3-E1 cells were investigated. The experiments were divided into three groups due to biomaterials used: Group A (composite materials of sintered bone modified with surface mineralization and P24, a peptide of bone morphogenetic protein-2); Group B (sintered bone modified with surface mineralization) and Group C (sintered bone only). The three groups were observed by scanning electron microscopy (SEM) before the experiments, respectively. Then MC3T3-E1 cells were cultured on the surfaces of the three kinds of material, respectively. The cell adhesion rate was assessed by precipitation method. The proliferative ability of MC3T3-E1 cells were measured with MTT assay. And the ALP staining and measurement of alkaline phosphatase (ALP) activity were performed to assess the differentiation of cells into osteoblasts. The SEM results showed that the materials in the three groups retained the natural pore structure and the pore sizes were in the range between 200-850 μm. The adhesive ratio measurements and MTT assay suggested that adhesion and proliferation of MC3T3-E1 cells in Group A were much higher than those in Group B and Group C (P bone modified with surface mineralization/P24 composite material was confirmed to improve the adhesion rate and proliferation and osteodifferentiation of MC3T3-E1 cells, and maintained their morphology.

  10. Adhesion of Trypanosoma cruzi trypomastigotes to fibronectin or laminin modifies tubulin and paraflagellar rod protein phosphorylation.

    Directory of Open Access Journals (Sweden)

    Eliciane C Mattos

    Full Text Available BACKGROUND: The unicellular parasite Trypanosoma cruzi is the causative agent of Chagaś disease in humans. Adherence of the infective stage to elements of the extracellular matrix (ECM, as laminin and fibronectin, is an essential step in host cell invasion. Although members of the gp85/TS, as Tc85, were identified as laminin and fibronectin ligands, the signaling events triggered on the parasite upon binding to these molecules are largely unexplored. METHODOLOGY/PRINCIPAL FINDINGS: Viable infective parasites were incubated with laminin, fibronectin or bovine serum albumin for different periods of time and the proteins were separated by bidimensional gels. The phosphoproteins were envisaged by specific staining and the spots showing phosphorylation levels significantly different from the control were excised and identified by MS/MS. The results of interest were confirmed by immunoblotting or immunoprecipitation and the localization of proteins in the parasite was determined by immunofluorescence. Using a host cell-free system, our data indicate that the phosphorylation contents of T. cruzi proteins encompassing different cellular functions are modified upon incubation of the parasite with fibronectin or laminin. CONCLUSIONS/SIGNIFICANCE: Herein it is shown, for the first time, that paraflagellar rod proteins and α-tubulin, major structural elements of the parasite cytoskeleton, are predominantly dephosphorylated during the process, probably involving the ERK1/2 pathway. It is well established that T. cruzi binds to ECM elements during the cell infection process. The fact that laminin and fibronectin induce predominantly dephosphorylation of the main cytoskeletal proteins of the parasite suggests a possible correlation between cytoskeletal modifications and the ability of the parasite to internalize into host cells.

  11. Dennexin peptides modeled after the homophilic binding sites of the neural cell adhesion molecule (NCAM) promote neuronal survival, modify cell adhesion and impair spatial learning

    DEFF Research Database (Denmark)

    Køhler, Lene B; Christensen, Claus; Rossetti, Clara

    2010-01-01

    , and the effect of dennexinA was independent of polysialic acid expression. Consistent with the effect of dennexinA on NCAM-mediated adhesion in vitro, the peptide impaired long-term memory retention in rats in the Morris water maze test. Thus, dennexins are novel site-specific pharmacological tools...

  12. rFN/Cad-11-Modified Collagen Type II Biomimetic Interface Promotes the Adhesion and Chondrogenic Differentiation of Mesenchymal Stem Cells

    Science.gov (United States)

    Guo, Hongfeng; Zhang, Yuan; Li, Zhengsheng; Kang, Fei; Yang, Bo; Kang, Xia; Wen, Can; Yan, Yanfei; Jiang, Bo; Fan, Yujiang

    2013-01-01

    Properties of the cell-material interface are determining factors in the successful function of cells for cartilage tissue engineering. Currently, cell adhesion is commonly promoted through the use of polypeptides; however, due to their lack of complementary or modulatory domains, polypeptides must be modified to improve their ability to promote adhesion. In this study, we utilized the principle of matrix-based biomimetic modification and a recombinant protein, which spans fragments 7–10 of fibronectin module III (heterophilic motif ) and extracellular domains 1–2 of cadherin-11 (rFN/Cad-11) (homophilic motif ), to modify the interface of collagen type II (Col II) sponges. We showed that the designed material was able to stimulate cell proliferation and promote better chondrogenic differentiation of rabbit mesenchymal stem cells (MSCs) in vitro than both the FN modified surfaces and the negative control. Further, the Col II/rFN/Cad-11-MSCs composite stimulated cartilage formation in vivo; the chondrogenic effect of Col II alone was much less significant. These results suggested that the rFN/Cad-11-modified collagen type II biomimetic interface has dual biological functions of promoting adhesion and stimulating chondrogenic differentiation. This substance, thus, may serve as an ideal scaffold material for cartilage tissue engineering, enhancing repair of injured cartilage in vivo. PMID:23919505

  13. Propriedades microestruturais de argamassas de cimento Portland com adições minerais e poliméricas utilizadas na fixação de porcelanato Study of the influence of additions on the adherence between polymer-modified mortars and porcelain stoneware tiles

    Directory of Open Access Journals (Sweden)

    A. E. F. S. Almeida

    2006-09-01

    characteristics of porcelain tiles, its application on building façades requires special attention, since this material differs from conventional ceramics and because façades are exposed to weathering that can damage ceramic revetments. Literature presents lots of researches about adhesive mortars properties employing ceramic tiles with higher water absorption (more than 3%. In a different way, we find about porcelain stoneware tiles with almost 0% water absorption, that is the most important cause of detachments between the back side of porcelain tiles and the mortar, for the reason that there is no mechanical adherence how occurs for porous ceramic tiles. The present study shows some properties of mortars with polymer and silica fume additions to fix porcelain tile, intending to solve the problems about the lack of adherence. The combination of polymer and silica fume to mortars results in excellent properties, which are ideal for repairs and revestments requiring high performance, thus justifying its study for the fixing of porcelain tiles. Procedures were carried out following the specifications of the NBR 14082 standard. This article presents adherence values for mortars containing different amounts of added polymer and silica, indicating the applicability of these mortars as construction material. Microstructural properties were based on mercury intrusion porosimetry tests and scanning electron microscopy of fractured samples.

  14. The comparison of properties and cost of material use of natural rubber and sand in manufacturing cement mortar for construction sub-base layer

    Science.gov (United States)

    Rahman, R.; Nemmang, M. S.; Hazurina, Nor; Shahidan, S.; Khairul Tajuddin Jemain, Raden; Abdullah, M. E.; Hassan, M. F.

    2017-11-01

    The main issue related to this research was to examine the feasibility of natural rubber SMR 20 in the manufacturing of cement mortar for sub-base layer construction. Subbase layers have certain functions that need to be fulfilled in order to assure strong and adequate permeability of pavement performance. In a pavement structure, sub-base is below the base and serves as the foundation for the overall pavement structure, transmitting traffic loads to the sub-grade and providing drainage. Based on this research, the natural rubber, SMR 20 was with the percentages of 0%, 5%, 10% and 15% to mix with sand in the manufacture of the cement mortar. This research describes some of the properties and cost of the materials for the natural rubber and sand in cement mortar manufacturing by laboratory testing. Effects of the natural rubber replacement on mechanical properties of mortar were investigated by laboratory testing such as compressive strength test and density. This study obtained the 5% of natural rubber replaced in sand can achieved the strength of normal mortar after 7 days and 28 days. The strength of cement mortar depends on the density of cement mortar. According to the cost of both materials, sand shows the lower cost in material for the cement mortar manufacturing than the uses of natural rubber. Thus, the convectional cement mortar which used sand need lower cost than the modified rubber cement mortar and the most economical to apply in industrial. As conclusion, the percentage of 5% natural rubber in the cement mortar would have the same with normal cement mortar in terms of the strength. However, in terms of the cost of the construction, it will increase higher than cost of normal cement mortar production. So that, this modified cement mortar is not economical for the road sub-base construction.

  15. FRP confined smart concrete/mortar

    Science.gov (United States)

    Xiao, Y.; Zhu, P. S.; Choi, K. G.; Wu, Y. T.; Huang, Z. Y.; Shan, B.

    2006-03-01

    In this study, fiber reinforced polymer (FRP) confined smart concrete/mortar sensors were invented and validated for significantly improved measurement range. Several trial mixes were made using cement mortar and micron-phase graphite powders at different mix proportions. Compressive loading tests were conducted on smart mortar cylinder specimens with or without FRP confinement. Two-probe method was used to detect the electrical resistance of the smart cement mortar specimens. Strong correlation was recognized between the stress and electric resistance of the smart mortar. The test results indicated that the FRP wrapping could significantly enlarge the range of such self-sensing property as a consequence of confinement.

  16. Influence of polyacrylic ester and silica fume on the mechanical properties of mortar for repair application

    Directory of Open Access Journals (Sweden)

    Chaohua Jiang

    2016-12-01

    Full Text Available Experimental investigations on the influence of different amounts of polyacrylic ester and silica fumes on the mechanical properties of mortar such as the compressive strength, splitting tensile strength, bonding strength, and abrasion resistance are presented in this article. The results show that the compressive and splitting tensile strength of mortar can be improved with the addition of polyacrylic ester and silica fumes. Results obtained from both the direct tensile bond test and flexural bond test indicate that the addition of polyacrylic ester and silica fumes improves the bond strength significantly, and the enhancement is more obvious with polyacrylic ester paste as interfacial adhesives. Furthermore, mortar incorporation of polyacrylic ester and silica fumes shows superior abrasion resistance compared to the control mortar. Therefore, the correct combination of polyacrylic ester and silica fumes to produce mortars has been shown to have synergistic effects, which results in excellent properties including high bond strength and superior abrasion resistance. Mortars containing polyacrylic ester and silica fumes are ideal for repairing concrete especially for hydraulic concrete structure.

  17. Experimental and numerical studies of hybrid PCM embedded in plastering mortar for enhanced thermal behaviour of buildings

    International Nuclear Information System (INIS)

    Kheradmand, Mohammad; Azenha, Miguel; Aguiar, José L.B. de; Castro-Gomes, João

    2016-01-01

    This paper proposes a methodology for improvement of energy efficiency in buildings through the innovative simultaneous incorporation of three distinct phase change materials (here termed as hybrid PCM) in plastering mortars for façade walls. The thermal performance of a hybrid PCM mortar was experimentally evaluated by comparing the behaviour of a prototype test cell (including hybrid PCM plastering mortar) subjected to realistic daily temperature profiles, with the behaviour of a similar prototype test cell, in which no PCM was added. A numerical simulation model was employed (using ANSYS-FLUENT) to validate the capacity of simulating temperature evolution within the prototype containing hybrid PCM, as well as to understand the contribution of hybrid PCM to energy efficiency. Incorporation of hybrid PCM into plastering mortars was found to have the potential to significantly reduce heating/cooling temperature demands for maintaining the interior temperature within comfort levels when compared to normal mortars (without PCM), or even mortars comprising a single type of PCM. - Highlights: • New concept of incorporation of more than 1 type of PCM in plastering mortars (hybrid PCM). • Assessment of thermal performance of hybrid PCM plastering mortar. • Thermo-physical properties of plastering mortars modified with PCMs incorporation. • Experimental and numerical simulations of thermal behaviour on laboratory scale prototype.

  18. Thermosetting materials from the radiation-modified polymer compositions, 2. Development of adhesion-active and thermostable thermosetting materials

    International Nuclear Information System (INIS)

    Kalkis, V.; Maksimovs, R.D.; Zicans, J.; Bocoka, T.; Revjakins, O.

    1999-01-01

    Methods that improve the adhesion and thermal stability of the thermosetting materials are considered. Experimental studies of the blends composed of polyethylene, ethylene-propylene-diene copolymer (with characteristic specific for rubbers) and mesomorphic copolyesters, using rheological, spectrometric, and thermomechanical methods, have shown that radiation modification improves the adhesion and deformation properties as well as thermal stability of these blends. Therefore, materials of such system can be successfully used, e.g., as elastic and adhesion-active thermosetting materials at temperature above 473 K. (author)

  19. 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.

  20. Flowability in crushed sand mortar

    Directory of Open Access Journals (Sweden)

    Cabrera, O. A.

    2010-12-01

    Full Text Available The present experimental study explored the relationship between mortar flowability and the voids content in crushed sand to determine the effect of grain shape and surface texture as well as dust content on the behaviour of fresh mortar. The findings revealed a close correlation between voids content and the volume of paste needed for mortar to begin to flow as a continuous material, mortar flowability and the water content needed to attain a given flowability. The comparison of the empirical findings to the results obtained with the Larrard (1, 2 model provided further information on the effect of sand grain morphology on fresh mortars.

    En el presente trabajo se plantea un estudio experimental de la fluidez de morteros basado en el contenido de vacíos de arenas machacadas, para comprender la influencia de la forma y textura superficial de los granos de arena y del contenido de polvo de las mismas sobre el estado fresco de morteros. Los resultados muestran la estrecha relación entre el contenido de vacíos entre granos y los volúmenes de pasta necesarios para iniciar el escurrimiento como un material continuo, la fluidez de los morteros, el contenido de agua para alcanzar una determinada fluidez, etc. El comportamiento evaluado se compara con resultados obtenidos aplicando el modelo de F. de Larrard (1, 2, permitiendo de este modo obtener mayor información de la influencia de la morfología de los granos de la arena sobre el estado fresco de los morteros.

  1. Enhancing the versatility of alternate current biosusceptometry (ACB) through the synthesis of a dextrose-modified tracer and a magnetic muco-adhesive cellulose gel

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Murillo L., E-mail: murillolongo@gmail.com [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Instituto de Biociências, Universidade Estadual Paulista, CP 510, 18618–970 Botucatu SP (Brazil); Calabresi, Marcos F.; Quini, Caio; Matos, Juliana F.; Miranda, José R.A.; Saeki, Margarida J. [Instituto de Biociências, Universidade Estadual Paulista, CP 510, 18618–970 Botucatu SP (Brazil); Bordallo, Heloisa N. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)

    2015-03-01

    Alternate Current Biosusceptometry (ACB) is a promising bio-magnetic method, radiation free and easily performed used for gastric emptying exams. Due to development on its sensitivity level, interesting nature, noninvasiveness and low cost it has attracted a lot of attention. In this work, magnetic nanoparticles of Mn–Zn ferrite as well as dextrose-modified nanoparticles were synthesized to be used as possible tracers in ACB gastric emptying exams. In addition, a magnetic muco-adhesive gel was obtained by modifying the ferrite nanoparticles with cellulose. Based on in-vivo tests in rats, we show that the pure ferrite nanoparticles, whose isoelectric point was found to be at pH = 3.2, present a great sensitivity to pH variations along the gastrointestinal tract, while the reduction of the isoelectric point by the dextrose modification leads to suitable nanoparticles for rapid gastric emptying examinations. On the other hand, the in-vivo tests show that the muco-adhesive cellulose gel presents substantial stomach adhesion and is a potential drug delivery system easily traceable by the ACB system.

  2. Enhancing the versatility of alternate current biosusceptometry (ACB) through the synthesis of a dextrose-modified tracer and a magnetic muco-adhesive cellulose gel

    International Nuclear Information System (INIS)

    Martins, Murillo L.; Calabresi, Marcos F.; Quini, Caio; Matos, Juliana F.; Miranda, José R.A.; Saeki, Margarida J.; Bordallo, Heloisa N.

    2015-01-01

    Alternate Current Biosusceptometry (ACB) is a promising bio-magnetic method, radiation free and easily performed used for gastric emptying exams. Due to development on its sensitivity level, interesting nature, noninvasiveness and low cost it has attracted a lot of attention. In this work, magnetic nanoparticles of Mn–Zn ferrite as well as dextrose-modified nanoparticles were synthesized to be used as possible tracers in ACB gastric emptying exams. In addition, a magnetic muco-adhesive gel was obtained by modifying the ferrite nanoparticles with cellulose. Based on in-vivo tests in rats, we show that the pure ferrite nanoparticles, whose isoelectric point was found to be at pH = 3.2, present a great sensitivity to pH variations along the gastrointestinal tract, while the reduction of the isoelectric point by the dextrose modification leads to suitable nanoparticles for rapid gastric emptying examinations. On the other hand, the in-vivo tests show that the muco-adhesive cellulose gel presents substantial stomach adhesion and is a potential drug delivery system easily traceable by the ACB system

  3. Enhancing the versatility of alternate current biosusceptometry (ACB) through the synthesis of a dextrose-modified tracer and a magnetic muco-adhesive cellulose gel.

    Science.gov (United States)

    Martins, Murillo L; Calabresi, Marcos F; Quini, Caio; Matos, Juliana F; Miranda, José R A; Saeki, Margarida J; Bordallo, Heloisa N

    2015-03-01

    Alternate Current Biosusceptometry (ACB) is a promising bio-magnetic method, radiation free and easily performed used for gastric emptying exams. Due to development on its sensitivity level, interesting nature, noninvasiveness and low cost it has attracted a lot of attention. In this work, magnetic nanoparticles of Mn-Zn ferrite as well as dextrose-modified nanoparticles were synthesized to be used as possible tracers in ACB gastric emptying exams. In addition, a magnetic muco-adhesive gel was obtained by modifying the ferrite nanoparticles with cellulose. Based on in-vivo tests in rats, we show that the pure ferrite nanoparticles, whose isoelectric point was found to be at pH=3.2, present a great sensitivity to pH variations along the gastrointestinal tract, while the reduction of the isoelectric point by the dextrose modification leads to suitable nanoparticles for rapid gastric emptying examinations. On the other hand, the in-vivo tests show that the muco-adhesive cellulose gel presents substantial stomach adhesion and is a potential drug delivery system easily traceable by the ACB system. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Effects of a hybrid micro/nanorod topography-modified titanium implant on adhesion and osteogenic differentiation in rat bone marrow mesenchymal stem cells.

    Science.gov (United States)

    Zhang, Wenjie; Li, Zihui; Huang, Qingfeng; Xu, Ling; Li, Jinhua; Jin, Yuqin; Wang, Guifang; Liu, Xuanyong; Jiang, Xinquan

    2013-01-01

    Various methods have been used to modify titanium implant surfaces with the aim of achieving better osseointegration. In this study, we fabricated a clustered nanorod structure on an acid-etched, microstructured titanium plate surface using hydrogen peroxide. We also evaluated biofunctionalization of the hybrid micro/nanorod topography on rat bone marrow mesenchymal stem cells. Scanning electron microscopy and x-ray diffraction were used to investigate the surface topography and phase composition of the modified titanium plate. Rat bone marrow mesenchymal stem cells were cultured and seeded on the plate. The adhesion ability of the cells was then assayed by cell counting at one, 4, and 24 hours after cell seeding, and expression of adhesion-related protein integrin β1 was detected by immunofluorescence. In addition, a polymerase chain reaction assay, alkaline phosphatase and Alizarin Red S staining assays, and osteopontin and osteocalcin immunofluorescence analyses were used to evaluate the osteogenic differentiation behavior of the cells. The hybrid micro/nanoscale texture formed on the titanium surface enhanced the initial adhesion activity of the rat bone marrow mesenchymal stem cells. Importantly, the hierarchical structure promoted osteogenic differentiation of these cells. This study suggests that a hybrid micro/nanorod topography on a titanium surface fabricated by treatment with hydrogen peroxide followed by acid etching might facilitate osseointegration of a titanium implant in vivo.

  5. Natural radioactivity levels and danger ratio in cements, concretes and mortars used in construction; Determinacion de niveles radiactivos naturales e indices de peligrosidad en cementos, hormigones y morteros utilizados en construccion

    Energy Technology Data Exchange (ETDEWEB)

    Meneses, J.; Pacheco, C.; Avila, J. M.; Miro, C.

    2010-07-01

    We have determined the natural radiation level in three types of adhesive cements, five types of concrete and two types of mortars of different strength normally used in the construction field. Of these materials, both concrete and mortars were prepared in our laboratories, cements the contrary were of a commercial nature.

  6. Investigations of salt mortar containing saliferous clay

    International Nuclear Information System (INIS)

    Walter, F.

    1992-01-01

    Saliferous clay mortar might be considered for combining individual salt bricks into a dense and tight long-term seal. A specific laboratory program was started to test mortars consisting of halite powder and grey saliferous clay of the Stassfurt from the Bleicherode salt mine. Clay fractions between 0 and 45% were used. The interest focused upon obtaining good workabilities of the mixtures as well as upon the permeability and compression strength of the dried mortar samples. Test results: 1) Without loss of quality the mortar can be mixed using fresh water. Apprx. 18 to 20 weight-% of the solids must be added as mixing water. 2) The porosity and the permeability of the mortar samples increases distinctly when equally coarse-grained salt power is used for mixing. 3) The mean grain size and the grain size distribution of the saliferous clay and the salt powder should be very similar to form a useful mortar. 4) The permeability of the mortar samples decreases with increasing clay fraction from 2 10 -12 m 2 to 2 10 -14 m 2 . The investigated samples, however, were large and dried at 100degC. 5) The uniaxial compressive strength of the clay mortar equals, at an average, only 4 MPa and decreases clearly with increasing clay fraction. Moist mortar samples did not show any measurable compressive strength. 6) Moistened saliferous clay mortar may show little temporary swelling. (orig./HP)

  7. The use of amorphous silica-alumina-based additive in the adhesive dry mixes of building materials

    Directory of Open Access Journals (Sweden)

    Loganina VI

    2018-01-01

    Full Text Available Proved the possibility of using amorphous aluminosilicate as a modifying agent for the adhesive dry mixes. Are given the data on the microstructure and chemical composition of the amorphous aluminosilicates. Installed , that the microstructure of the synthetic additives is characterized by particles of round shape, dimensions 5,208-5,704 μm, Also there are particles of elongated shape in size 7.13-8.56 μm. Predominate chemical elements O, Si, Na, S, and Al in quantity 60.69%, 31.26%, 24.23%, 18.69% and 8.29% respectively. Described the character changes in the rheological properties of cement-sand mortar, depending on the percentage of additives. Determined, that the introduction in the cement-sand mortar the additive based on amorphous aluminosilicate leads to higher values of plastic strength. Are given the model of cement stone strength using synthetic additives in the formulation. The results of the evaluation of the frost resistance of cement-based tile adhesives with the use of amorphous aluminosilicates as a modifying additive are presented. In the article is determined the mark on frost resistance of tile glue and frost resistance of the contact zone of tile glue. The evaluation of the performance properties of the layer of tile adhesive on the basis of cement, dry mixes. The calculation of the value of displacement of the adhesive layer made on the basis of the developed recipes cement dry mixes applied to a vertical surface. Experimental data obtained values of displacement tiles relative to the substrate. Described the results of physical and mechanical properties of tile adhesive made on the basis of the developed adhesive dry mix formulations.

  8. Wood : adhesives

    Science.gov (United States)

    A.H. Conner

    2001-01-01

    This chapter on wood adhesives includes: 1) Classification of wood adhesives 2) Thermosetting wood adhesives 3) Thermoplastic adhesives, 4) Wood adhesives based on natural sources 5) Nonconventional bonding of wood 6) Wood bonding.

  9. 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.

  10. 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.

  11. Strength of mortar containing rubber tire particle

    Science.gov (United States)

    Jusoh, M. A.; Abdullah, S. R.; Adnan, S. H.

    2018-04-01

    The main focus in this investigation is to determine the strength consist compressive and tensile strength of mortar containing rubber tire particle. In fact, from the previous study, the strength of mortar containing waste rubber tire in mortar has a slightly decreases compare to normal mortar. In this study, rubber tire particle was replacing on volume of fine aggregate with 6%. 9% and 12%. The sample were indicated M0 (0%), M6 (6%), M9 (9%) and M12 (12%). In this study, two different size of sample used with cube 100mm x 100mm x 100mm for compressive strength and 40mm x 40mm x 160mm for flexural strength. Morphology test was conducted by using Scanning electron microscopic (SEM) were done after testing compressive strength test. The concrete sample were cured for day 3, 7 and 28 before testing. Results compressive strength and flexural strength of rubber mortar shown improved compare to normal mortar.

  12. Moisture transport properties of mortar and mortar joint: A NMR study

    NARCIS (Netherlands)

    Brocken, H.J.P.; Adant, O.C.G.; Pel, L.

    1997-01-01

    The moisture transport in mortar and mortar joint often is an important parameter in degeneration of brick masonry and other block constructions. In this study, the influence of single additives on the moisture transport properties of mortar is investigated. Due to water extraction during brick

  13. Moisture transport properties of mortar and mortar joint: a NMR study

    NARCIS (Netherlands)

    Brocken, H.J.P.; Adan, O.C.G.; Pel, L.

    1997-01-01

    The moisture transport in mortar and mortar joint often is an important parameter in degeneration of brick masonry and other block constructions. In this study, the influence of single additives on the moisture transport properties of mortar is investigated. Due to water extraction during brick

  14. The adhesion and growth of vascular smooth muscle cells in cultures on carboranethiol-modified gold films

    Czech Academy of Sciences Publication Activity Database

    Pařízek, Martin; Baše, Tomáš; Londesborough, Michael Geoffrey Stephen; Lisá, Věra; Bačáková, Lucie

    2008-01-01

    Roč. 11, 81-84 (2008), s. 117-119 ISSN 1429-7248 R&D Projects: GA AV ČR(CZ) KAN400480701 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z40320502 Keywords : bioactive coating * cell adhesion * cell growth Subject RIV: EI - Biotechnology ; Bionics

  15. 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.

  16. Synthesis and characterization of methylcellulose from cellulose extracted from mango seeds for use as a mortar additive

    Directory of Open Access Journals (Sweden)

    Júlia G. Vieira

    2012-01-01

    Full Text Available Methylcellulose was produced from the fibers of Mangifera indica L. Ubá mango seeds. MCD and MCI methylcellulose samples were made by heterogeneous methylation, using dimethyl sulfate and iodomethane as alkylating agents, respectively. The materials produced were characterized for their thermal properties (DSC and TGA, crystallinity (XRD and Degree of Substitution (DS in the chemical route. The cellulose derivatives were employed as mortar additive in order to improve mortar workability and adhesion to the substrate. These properties were evaluated by means of the consistency index (CI and bond tensile strength (TS tests. The methylcellulose (MCD and MCI samples had CI increased by 27.75 and 71.54% and TS increased by 23.33 and 29.78%, respectively, in comparison to the reference sample. Therefore, the polymers can be used to produce adhesive mortars.

  17. Effect of chitosan ethers on fresh state properties of lime mortars

    Science.gov (United States)

    Vyšvařil, M.; Žižlavský, T.

    2017-10-01

    The fresh state properties of mortars are eminently important since determine the material workability and also have a great influence on its hardened state characteristics. In this paper, the behaviour of fresh lime mortars modified by etherified derivatives of chitosan (hydroxypropylchitosan (HPCH) and carboxymethylchitosan (CMCH)) is assessed with the purpose of exploring a new application of such derivatives as lime mortar admixtures. The rheological parameters (relative yield stress, consistency coefficient and fluidity index) and viscoelastic properties were correlated with flow table tests, relative density measurements, water retention abilities of mortars and air content in mortars. Results were seen to be strongly dependent on substituents of the chitosan. Non-ionic derivative (HPCH) had a plasticizing influence on the mortars; the ionic CMCH showed the thickening effect. The effect of chitosan ethers was found to be dosage-dependent. CMCH had low impact on water retention, while HPCH displayed high water retention capability. It was concluded, that the ionic derivative (CMCH) is very similar by its viscosity enhancing effect to starch ether.

  18. Alternative design of pipe sleeve for liquid removal mechanism in mortar slab layer

    Science.gov (United States)

    Nazri, W. M. H. Wan; Anting, N.; Lim, A. J. M. S.; Prasetijo, J.; Shahidan, S.; Din, M. F. Md; Anuar, M. A. Mohd

    2017-11-01

    Porosity is one of the mortar’s characteristics that can cause problems, especially in the room space that used high amount of water, such as bathrooms. Waterproofing is one of the technology that normally used to minimize this problem which is preventing deep penetration of liquid water or moisture into underlying concrete layers. However, without the proper mechanism to remove liquid water and moisture from mortar system, waterproofing layer tends to be damaged after a long period of time by the static formation of liquid water and moisture at mortar layer. Thus, a solution has been proposed to drain out water that penetrated into the mortar layer. This paper introduces a new solution using a Modified Pipe Sleeve (MPS) that installed at the mortar layer. The MPS has been designed considering the percentage surface area of the pipe sleeve that having contact with mortar layer (2%, 4%, 6%, 8% and 10%) with angle of holes of 60°. Infiltration test and flow rate test have been conducted to identify the effectiveness of the MPS in order to drain out liquid water or moisture from the mortar layer. In this study shows that, MPS surface area 10%, angled 60°, function effectively as a water removal compared to other design.

  19. Marginal microleakage of resin-modified glass-ionomer and composite resin restorations: Effect of using etch-and-rinse and self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2012-01-01

    Full Text Available Objectives: Previous studies have shown that dental adhesives increase the bond strength of resin-modified glass-ionomer (RMGI restorative materials to dentin. This in vitro study has evaluated the effect of etch-and-rinse and self-etch bonding systems v/s cavity conditioner, and in comparison to similar composite resin restorations on maintaining the marginal sealing of RMGI restorations. Materials and Methods: 98 rectangular cavities (2.5×3×1.5 mm were prepared on buccal and palatal aspects of 49 human maxillary premolars, randomly divided into 7 groups (N=14. The cavities in groups 1, 2 and 3 were restored using a composite resin (APX. The cavities in groups 4, 5, 6 and 7 were restored using a resin-modified glass-ionomer (Fuji II LC. Before restoring, adhesive systems (Optibond FL = OFL, three-step etch-and-rinse; One Step Plus = OSP, two-step etch-and-rinse; Clearfil Protect Bond = CPB, two-step self-etch were used as bonding agents in groups 1-6 as follow: OFL in groups 1 and 4, OSP in groups 2 and 5, and CPB in groups 3 and 6, respectively. The specimens in group 7 were restored with GC cavity conditioner and Fuji II LC. All the specimens were thermo-cycled for 1000 cycles. Microleakage scores were determined using dye penetration method. Statistical analyzes were carried out with Kruskal-Wallis and Mann-Whitney U tests (α=0.05. Results: There were significant differences in microleakage scores at both enamel and dentinal margins between the study groups (P<0.05. The lowest microleakage scores at enamel and dentin margins of RMGI restorations were observed in group 6. Conclusion: Use of two-step self-etch adhesive, prior to restoring cervical cavities with RMGIC, seems to be more efficacious than the conventional cavity conditioner in decreasing marginal microleakage.

  20. 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…

  1. Effect of Nanosilica Particle Size on the Water Permeability, Abrasion Resistance, Drying Shrinkage, and Repair Work Properties of Cement Mortar Containing Nano-SiO2

    Directory of Open Access Journals (Sweden)

    Sattawat Haruehansapong

    2017-01-01

    Full Text Available This work presents the effect of nanosilica particle sizes on durability properties and repair work properties of cement mortar containing nanosilica (NS. Three different NS particle sizes of 12, 20, and 40 nm were used and compared with those of cement mortar without NS and cement mortar with silica fume (SF. Interesting results were obtained in which the particle size of NS affected directly the abrasion resistance and water permeability. NS with particle size of 40 nm is the optimum size and gave the highest abrasion resistance and water permeability. For repair work properties, cement mortars containing NS (12 and 20 nm and SF experienced higher drying shrinkage than that of cement mortar without NS and then presented cracking behavior and debonding between the cement mortars and concrete substrate. Cement mortar containing 40 nm of NS gave the lowest drying shrinkage, the lowest crack number, and the highest adhesive strength. These results indicate that the particle size of NS affected not only the durability properties but also the repair work properties of cement mortar.

  2. Adsorption of carbon-14 on mortar

    International Nuclear Information System (INIS)

    Matsumoto, Junko; Banba, Tsunetaka; Muraoka, Susumu

    1995-01-01

    The sorption experiments of carbon-14 on the mortar grain (grain size: 0.50--1.0 mm) focused on the chemical form of the carbon-14 were carried out by the batch method. Three kinds of carbon-14 chemical form were used for the experiments: sodium carbonate (Na 2 14 CO 3 ) as the inorganic radiocarbon, and sodium acetate (CH 3 14 COONa) and acetaldehyde ( 14 CH 3 14 CHO) as the organic radiocarbons. 0.30 gram samples of mortar were soaked in the solution with carbon-14 at 15 C for periods of up to 160 days. At the end of each run, carbon-14 concentrations in the supernatants were determined before and after centrifugation (3,500 rpm., 1 hr). In the mortar-sodium carbonate system, the retention process of carbon-14 related to reaction on the surface of the mortar was speculated as follows. First, 3CaO-SiO 2 and 2CaO-SiO 2 of the mortar components contact with water and produce Ca(OH) 2 . Ca(OH) 2 produces Ca 2+ and OH - in the solution. Then, calcite forms from Ca 2+ and CO 3 2- in the solution. Thus, the sorption ratio of carbon-14 onto mortar will be high until mortar has been completely carbonated because Ca 2+ is rich in the mortar and the solubility of calcite is low. In the mortar-organic carbon system, the soluble organic carbon-14 is hardly sorbed on the surface of the mortar. Therefore, the cementitious materials may not inhibit the release of organic radiocarbons from the low-level radioactive wastes, contrary to the case of inorganic radiocarbon

  3. Experimental and numerical study of a modified ASTM C633 adhesion test for strongly-bonded coatings

    Energy Technology Data Exchange (ETDEWEB)

    Bernardie, Raphaëlle; Berkouch, Reda; Valette, Stéphane; Absi, Joseph; Lefort, Pierre [University of Limoges, Limoges Cedex (France)

    2017-07-15

    When coatings are strongly bonded to their substrates it is often difficult to measure the adhesion values. The proposed method, which is suggested naming “silver print test”, consists in covering the central part of the samples with a thin layer of silver paint, before coating. The process used for testing this new method was the Air plasma spraying (APS), and the materials used were alumina coatings on C35 steel substrates, previously pre-oxidized in CO{sub 2}. The silver painted area was composed of small grains that did not oxidize but that significantly sintered during the APS process. The silver layer reduced the surface where the coating was linked to the substrate, which allowed its debonding, using the classical adhesion test ASTM C633-13, while the direct use of this test (without silver painting) led to ruptures inside the glue used in this test. The numerical modelling, based on the finite element method with the ABAQUS software, provided results in good agreement with the experimental measurements. This concordance validated the used method and allowed accessing to the values of adherence when the experimental test ASTM C633-13 failed, because of ruptures in the glue. After standardization, the “silver print test” might be used for other kinds of deposition methods, such as PVD, CVD, PECVD.

  4. Adhesive interactions with wood

    Science.gov (United States)

    Charles R. Frihart

    2004-01-01

    While the chemistry for the polymerization of wood adhesives has been studied systematically and extensively, the critical aspects of the interaction of adhesives with wood are less clearly understood. General theories of bond formation need to be modified to take into account the porosity of wood and the ability of chemicals to be absorbed into the cell wall....

  5. Compressive and flexural strength of cement mortar stabilized with ...

    African Journals Online (AJOL)

    Mortar is a material with wide range of applications in the construction industry. However, plain mortar matrices are usually brittle and often cracks and fails more suddenly than reinforced mortars. In this study, the compressive and flexural strengths of cement mortar stabilized with Raffia Palm Fruit Peel (RPFP) as fibre were ...

  6. Effect of resin-modified glass-ionomer cement lining and composite layering technique on the adhesive interface of lateral wall

    Directory of Open Access Journals (Sweden)

    Larissa Marinho AZEVEDO

    2015-06-01

    Full Text Available Interface integrity can be maintained by setting the composite in a layering technique and using liners. Objective The aim of this in vitro study was to verify the effect of resin-modified glass-ionomer cement (RMGIC lining and composite layering technique on the bond strength of the dentin/resin adhesive interface of lateral walls of occlusal restorations. Material and Methods Occlusal cavities were prepared in 52 extracted sound human molars, randomly assigned into 4 groups: Group 2H (control – no lining + two horizontal layers; Group 4O: no lining + four oblique layers; Group V-2H: RMGIC lining (Vitrebond + two horizontal layers; and Group V-4O: RMGIC lining (Vitrebond + four oblique layers. Resin composite (Filtek Z250, 3M ESPE was placed after application of an adhesive system (Adper™ Single Bond 2, 3M ESPE dyed with a fluorescent reagent (Rhodamine B to allow confocal microscopy analysis. The teeth were stored in deionized water at 37oC for 24 hours before being sectioned into 0.8 mm slices. One slice of each tooth was randomly selected for Confocal Laser Scanning Microscopy (CLSM analysis. The other slices were sectioned into 0.8 mm x 0.8 mm sticks to microtensile bond strength test (MPa. Data were analyzed by two-way ANOVA and Fisher's test. Results There was no statistical difference on bond strength among groups (p>0.05. CLSM analysis showed no significant statistical difference regarding the presence of gap at the interface dentin/resin among groups. Conclusions RMGIC lining and composite layering techniques showed no effect on the microtensile bond strength and gap formation at the adhesive interface of lateral walls of high C-factor occlusal restorations.

  7. CAD/CAM monolithic restorations and full-mouth adhesive rehabilitation to restore a patient with a past history of bulimia: the modified three-step technique.

    Science.gov (United States)

    Vailati, Francesca; Carciofo, Sylvain

    2016-01-01

    Due to an increasing awareness about dental erosion, many clinicians would like to propose treatments even at the initial stages of the disease. However, when the loss of tooth structure is visible only to the professional eye, and it has not affected the esthetics of the smile, affected patients do not usually accept a full-mouth rehabilitation. Reducing the cost of the therapy, simplifying the clinical steps, and proposing noninvasive adhesive techniques may promote patient acceptance. In this article, the treatment of an ex-bulimic patient is illustrated. A modified approach of the three-step technique was followed. The patient completed the therapy in five short visits, including the initial one. No tooth preparation was required, no anesthesia was delivered, and the overall (clinical and laboratory) costs were kept low. At the end of the treatment, the patient was very satisfied from a biologic and functional point of view.

  8. Development of lightweight mortars targeted on the high strength, low density and low permeability

    NARCIS (Netherlands)

    Spiesz, P.R.; Yu, Q.; Brouwers, H.J.H.; Uzoegbo, H.C.; Schmidt, W.

    2013-01-01

    This article presents a mix design methodology for the development of cement-based lightweight mortars. Expanded-glass lightweight aggregates were used in this study as the lightweight material. The mix design was developed applying the packing theory using the modified Andreasen and Andersen model

  9. Amine modified polyethylenes, prepared in near critical propane, as adhesion promoting agents in multilayered HDPE/PET films

    NARCIS (Netherlands)

    Gooijer, de J.M.; Scheltus, M.; Koning, C.E.

    2001-01-01

    High d. polyethylene (HDPE) grafted with 0.13, 0.40 and 1.04 wt% maleic anhydride (abbreviation PEMA) was modified with an excess of a variety of diamines in near crit. propane. The resulting amic acid groups were quant. imidized to the corresponding imide (PEMI) in the melt. Increasing the

  10. Effect of hydrated lime on compressive strength mortar of fly ash laterite soil geopolymer mortar

    Science.gov (United States)

    Wangsa, F. A.; Tjaronge, M. W.; Djamaluddin, A. R.; Muhiddin, A. B.

    2017-11-01

    This paper explored the suitability of fly ash, hydrated lime, and laterite soil with several activator (sodium hydroxide and sodium tiosulfate) to produce geopolymer mortar. Furthermore, the heat that released by hydrated lime was used instead of oven curing. In order to produce geopolymer mortar without oven curing, three variations of curing condition has been applied. Based on the result, all the curing condition showed that the hardener mortar can be produced and exhibited the increasing of compressive strength of geopolymer mortar from 3 days to 7 days without oven curing.

  11. Modeling and numerical simulation of interior ballistic processes in a 120mm mortar system

    Science.gov (United States)

    Acharya, Ragini

    by using a high-resolution Godunov-type shock-capturing approach was used where the discretization is done directly on the integral formulation of the conservation laws. A linearized approximate Riemann Solver was modified in this work for the two-phase flows to compute fully non-linear wave interactions and to directly provide upwinding properties in the scheme. An entropy fix based on Harten-Heyman method was used with van Leer flux limiter for total variation diminishing. The three dimensional effects were simulated by incorporating an unsplit multi-dimensional wave propagation method, which accounted for discontinuities traveling in both normal and oblique coordinate directions. For each component, the predicted pressure-time traces showed significant pressure wave phenomena, which closely simulated the measured pressure-time traces obtained at PSU. The pressure-time traces at the breech-end of the mortar tube were obtained at Aberdeen Test Center with 0, 2, and 4 charge increments. The 3D-MIB code was also used to simulate the effect of flash tube vent-hole pattern on the pressure-wave phenomenon in the ignition cartridge. A comparison of the pressure difference between primer-end and projectile-end locations of the original and modified ignition cartridges with each other showed that the early-phase pressure-wave phenomenon can be significantly reduced with the modified pattern. The flow property distributions predicted by the 3D-MIB for 0, 2, and 4 charge increment cases as well the projectile dynamics predictions provided adequate validation of theory by experiments.

  12. Biomimetic modified clinical-grade POSS-PCU nanocomposite polymer for bypass graft applications: a preliminary assessment of endothelial cell adhesion and haemocompatibility.

    Science.gov (United States)

    Solouk, Atefeh; Cousins, Brian G; Mirahmadi, Fereshteh; Mirzadeh, Hamid; Nadoushan, Mohammad Reza Jalali; Shokrgozar, Mohammad Ali; Seifalian, Alexander M

    2015-01-01

    To date, there are no small internal diameter (nanocomposite polymers, which contain binding sites and ligands for cell surface receptors similar to extracellular matrix (ECM) will positively influence the attachment and proliferation of ECs. Since, the surface of POSS-PCU is inert and not directly suitable for immobilisation of biomolecules, plasma graft polymerisation is a suitable method to modify the surface properties ready for immobilisation and biofunctionalisation. POSS-PCU was activated by plasma treatment in air/O2 to from hydroperoxides (-OH, -OOH), and then carboxylated via plasma polymerisation of a 30% acrylic acid solution (Poly-AA) using a two-step plasma treatment (TSPT) process. Collagen type I, a major component of ECM, was covalently immobilised to mimic the ECM structures to ECs (5mg/ml) using a two-step chemical reaction using EDC chemistry. Successful immobilisation of poly-AA and collagen on to the nanocomposites was confirmed using Toluidine Blue staining and the Bradford assay. Un-treated POSS-PCU served as a simple control. The impact of collagen grafting on the physical, mechanical and biological properties of POSS-PCU was evaluated via contact angle (θ) measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA), ECs adhesion and proliferation followed by platelet adhesion and haemolysis ratio (HR) tests. Poly-AA content on each of the plasma treated nanocomposite films increased on Low, Med and High samples due to more carboxylic acid (-COOH) groups at the surface forming amide (-NH2) bonds. The amount of -COOH groups on each of the Low, Med and High nanocomposites correlated with Poly-AA grafting density at 14.7±0.9, 18.9±0.9, and 34.2±2.4 μg/cm(2). Immobilisation of collagen type I on to nanocomposite surface was also found to increase significantly on the Low, Med and High samples from 22±4, 150±15, and 219±17 μg/cm(2), respectively. The level of ECs and their

  13. physico-chemical studies on polymer impregnated blending cement mortar composite

    International Nuclear Information System (INIS)

    Abdel-Rahman, H.A.

    2001-01-01

    as the increasing of the demand on a specific performance characteristics in concrete such as improved strength, low heat, sulfate resistance, improved impermeability and certain other applications. some of the industrial waste materials such as the blast-furnace slag, silica fume and fly ash were mixed with the cement clinker to produce blended cement . the use of these materials modifies the strength, pore structure and permeability of hardened cement mortar or concrete. the incorporation of blast furnace slag and silica fume in the hardened blended cement mortar or concrete is a common practice recently due to technological, economical and environmental benefits

  14. 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.

  15. Titanium Socket for 120 mm Mortar Base

    National Research Council Canada - National Science Library

    2004-01-01

    .... However, its unique properties also make it difficult to machine productively. ARDEC was spending excessive time turning a profile of a ball socket into the component that supports the mortar tube...

  16. Improved extraction of ePTFE and medical adhesive modified defibrillation leads from the coronary sinus and great cardiac vein.

    Science.gov (United States)

    Wilkoff, Bruce L; Belott, Peter H; Love, Charles J; Scheiner, Avram; Westlund, Randy; Rippy, Marian; Krishnan, Mohan; Norlander, Barry E; Steinhaus, Bruce; Emmanuel, Janson; Zeller, Peter J

    2005-03-01

    Permanent leads with shocking coils for defibrillation therapy are sometimes implanted in the coronary sinus (CS) and great cardiac vein (GCV). These shocking coils, as documented by pathologic examination of animal investigations, often become tightly encapsulated by fibrosis and can be very difficult to remove. One of three configurations of the Guidant model 7109 Perimeter coronary sinus shocking lead was implanted into the distal portion of the GCV of 24 sheep for up to 14 months. Group 1 had unmodified coils (control), group 2 had coils backfilled with medical adhesive (MA), and Group 3 had coils coated with expanded polytetrafluoroethylene (ePTFE). Eighteen leads, three from each group at 6 and 14 months were transvenously extracted from the left jugular vein. The remaining six animals were not subject to extraction. All animals were euthanized for pathological and microscopic examination. All six of the control, three of the MA, and one of the ePTFE leads required the use of an electrosurgical dissection sheath (EDS) for extraction. Five control, two MA, and none of the ePTFE leads had significant fibrotic attachments to the shocking coils. Significant trauma was observed at necropsy for those leads requiring the use of the EDS for extraction. Tissue ingrowth is a major impediment to the removal of defibrillation leads implanted in the CS and GCV of sheep. Reduction of tissue ingrowth by coating the shocking coils with ePTFE or by backfilling with MA facilitates transvenous lead removal with reduced tissue trauma.

  17. Mechanical characterization of sisal reinforced cement mortar

    OpenAIRE

    R. Fujiyama; F. Darwish; M.V. Pereira

    2014-01-01

    This work aims at evaluating the mechanical behavior of sisal fiber reinforced cement mortar. The composite material was produced from a mixture of sand, cement, and water. Sisal fibers were added to the mixture in different lengths. Mechanical characterization of both the composite and the plain mortar was carried out using three point bend, compression, and impact tests. Specimens containing notches of different root radii were loaded in three point bending in an effort to determine the eff...

  18. 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.

  19. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Denture Adhesives

    Science.gov (United States)

    ... Devices Products and Medical Procedures Dental Devices Denture Adhesives Share Tweet Linkedin Pin it More sharing options ... Wearers Reporting Problems to the FDA Background Denture adhesives are pastes, powders or adhesive pads that may ...

  1. Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

    International Nuclear Information System (INIS)

    Li, Zhengqi

    2017-01-01

    The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa) steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete. [es

  2. Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

    Directory of Open Access Journals (Sweden)

    Zhengqi Li

    2017-03-01

    Full Text Available The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete.

  3. Rilem TC 203-RHM: Repair mortars for historic masonry. Requirements for repointing mortars for historic masonry

    NARCIS (Netherlands)

    Hees, R.P.J. van; Groot, C.; Hughes, J.J.; Balen, K. van; Bicer-Simsir, B.; Binda, L.; Elsen, J.; Konow, T. von; Lindqvist, J.E.; Papayanni, I.; Subercaseaux, M.; Tedeschi, C.; Toumbakari, E.E.; Thompson, B.

    2012-01-01

    This paper gives a summary of functional and performance requirements for repointing mortars for historic masonry (design, execution and maintenance). Successful performance of repair and conservation of mortar in historic masonry requires more care with design and execution than with modern

  4. Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

    Energy Technology Data Exchange (ETDEWEB)

    Razavizadeh, Mahmoud; Jamshidi, Masoud, E-mail: mjamshidi@iust.ac.ir

    2016-08-30

    Highlights: • In this research UV-irradiated PET fabric was chemically modified. • The fabric at first carboxylated under UV irradiation using glutaric anhydride, then it was grafted using isocyanate (i.e. MDI). • The surface of the fabric was characterized before and after each treating satge. • The composite samples were prepared and tested for T-Peel test. The surfaces of the fabrics were surface characterized to understand. - Abstract: Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

  5. Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

    International Nuclear Information System (INIS)

    Razavizadeh, Mahmoud; Jamshidi, Masoud

    2016-01-01

    Highlights: • In this research UV-irradiated PET fabric was chemically modified. • The fabric at first carboxylated under UV irradiation using glutaric anhydride, then it was grafted using isocyanate (i.e. MDI). • The surface of the fabric was characterized before and after each treating satge. • The composite samples were prepared and tested for T-Peel test. The surfaces of the fabrics were surface characterized to understand. - Abstract: Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

  6. Biomimetic modified clinical-grade POSS-PCU nanocomposite polymer for bypass graft applications: A preliminary assessment of endothelial cell adhesion and haemocompatibility

    International Nuclear Information System (INIS)

    Solouk, Atefeh; Cousins, Brian G.; Mirahmadi, Fereshteh; Mirzadeh, Hamid; Nadoushan, Mohammad Reza Jalali; Shokrgozar, Mohammad Ali; Seifalian, Alexander M.

    2015-01-01

    Background: To date, there are no small internal diameter (< 5 mm) vascular grafts that are FDA approved for clinical use due to high failure rates from thrombosis and unwanted cell proliferation. The ideal conditions to enhance bioengineered grafts would be the blood contacting lumen of the bypass graft fully covered by endothelial cells (ECs). As a strategy towards this aim, we hypothesized that by immobilising biomolecules on the surface of the polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) nanocomposite polymers, which contain binding sites and ligands for cell surface receptors similar to extracellular matrix (ECM) will positively influence the attachment and proliferation of ECs. Since, the surface of POSS-PCU is inert and not directly suitable for immobilisation of biomolecules, plasma graft polymerisation is a suitable method to modify the surface properties ready for immobilisation and biofunctionalisation. Methods: POSS-PCU was activated by plasma treatment in air/O 2 to from hydroperoxides (–OH, –OOH), and then carboxylated via plasma polymerisation of a 30% acrylic acid solution (Poly-AA) using a two-step plasma treatment (TSPT) process. Collagen type I, a major component of ECM, was covalently immobilised to mimic the ECM structures to ECs (5 mg/ml) using a two-step chemical reaction using EDC chemistry. Successful immobilisation of poly-AA and collagen on to the nanocomposites was confirmed using Toluidine Blue staining and the Bradford assay. Un-treated POSS-PCU served as a simple control. The impact of collagen grafting on the physical, mechanical and biological properties of POSS-PCU was evaluated via contact angle (θ) measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA), ECs adhesion and proliferation followed by platelet adhesion and haemolysis ratio (HR) tests. Results: Poly-AA content on each of the plasma treated nanocomposite films

  7. Biomimetic modified clinical-grade POSS-PCU nanocomposite polymer for bypass graft applications: A preliminary assessment of endothelial cell adhesion and haemocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Solouk, Atefeh [Biomedical Engineering Faculty, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Cousins, Brian G., E-mail: brian.cousins@ucl.ac.uk [Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London (United Kingdom); Mirahmadi, Fereshteh [Biomedical Engineering Faculty, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Mirzadeh, Hamid [Polymer Engineering Faculty, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Nadoushan, Mohammad Reza Jalali [Department of Pathology, School of Medicine, Shahed University, Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Seifalian, Alexander M. [Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London (United Kingdom)

    2015-01-01

    Background: To date, there are no small internal diameter (< 5 mm) vascular grafts that are FDA approved for clinical use due to high failure rates from thrombosis and unwanted cell proliferation. The ideal conditions to enhance bioengineered grafts would be the blood contacting lumen of the bypass graft fully covered by endothelial cells (ECs). As a strategy towards this aim, we hypothesized that by immobilising biomolecules on the surface of the polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) nanocomposite polymers, which contain binding sites and ligands for cell surface receptors similar to extracellular matrix (ECM) will positively influence the attachment and proliferation of ECs. Since, the surface of POSS-PCU is inert and not directly suitable for immobilisation of biomolecules, plasma graft polymerisation is a suitable method to modify the surface properties ready for immobilisation and biofunctionalisation. Methods: POSS-PCU was activated by plasma treatment in air/O{sub 2} to from hydroperoxides (–OH, –OOH), and then carboxylated via plasma polymerisation of a 30% acrylic acid solution (Poly-AA) using a two-step plasma treatment (TSPT) process. Collagen type I, a major component of ECM, was covalently immobilised to mimic the ECM structures to ECs (5 mg/ml) using a two-step chemical reaction using EDC chemistry. Successful immobilisation of poly-AA and collagen on to the nanocomposites was confirmed using Toluidine Blue staining and the Bradford assay. Un-treated POSS-PCU served as a simple control. The impact of collagen grafting on the physical, mechanical and biological properties of POSS-PCU was evaluated via contact angle (θ) measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA), ECs adhesion and proliferation followed by platelet adhesion and haemolysis ratio (HR) tests. Results: Poly-AA content on each of the plasma treated nanocomposite films

  8. Immobilization of IFR salt wastes in mortar

    International Nuclear Information System (INIS)

    Fischer, D.F.; Johnson, T.R.

    1988-01-01

    Portland cement-base mortars are being considered for immobilizing chloride salt wastes produced by the fuel cycles of Integral Fast Reactors (IFR). The IFR is a sodium-cooled fast reactor with metal alloy fuels. It has a close-coupled fuel cycle in which fission products are separated from the actinides in an electrochemical cell operating at 500/degree/C. This cell has a liquid cadmium anode in which the fuels are dissolved and a liquid salt electrolyte. The salt will be a mixture of either lithium, potassium, and sodium chlorides or lithium, calcium, barium, and sodium chlorides. One method being considered for immobilizing the treated nontransuranic salt waste is to disperse the salt in a portland cement-base mortar that will be sealed in corrosion-resistant containers. For this application, the grout must be sufficiently fluid that it can be pumped into canister-molds where it will solidify into a strong, leach-resistant material. The set times must be longer than a few hours to allow sufficient time for processing, and the mortar must reach a reasonable compressive strength (/approximately/7 MPa) within three days to permit handling. Because fission product heating will be high, about 0.6 W/kg for a mortar containing 10% waste salt, the effects of elevated temperatures during curing and storage on mortar properties must be considered

  9. Effect of Rebonding on the Bond Strength of Orthodontic Tubes: A Comparison of Light Cure Adhesive and Resin-Modified Glass Ionomer Cement In Vitro

    Directory of Open Access Journals (Sweden)

    Monika Aleksiejunaite

    2017-01-01

    Full Text Available The purpose of this study was to determine the impact of different enamel preparation procedures and compare light cure composite (LCC and resin-modified glass ionomer (RMGI on the bond strength of orthodontic metal tubes rebonded to the enamel. Twenty human molars were divided into two groups (n=10. Tubes were bonded using LCC (Transbond XT in group 1 and RMGI (Fuji Ortho LC in group 2. The tubes in each group were bonded following manufacturers’ instructions (experiment I and then debonded using testing machine. Then, the same brackets were sandblasted and rebonded twice. Before the first rebonding, the enamel was cleaned using carbide bur (experiment II and before second rebonding, it was cleaned using carbide bur and soda blasted (experiment III. Mann–Whitney and Wilcoxon signed-rank tests showed no significant difference between RMGI and LCC bond strengths in case of normal bonding and rebonding, when enamel was cleaned using carbide bur before rebonding. Enamel soda blasting before rebonding significantly increased RMGI tensile bond strength value compared to LLC (p<0.05. LCC and RMGI (especially RMGI provide sufficient bond strengths for rebonding of molar tubes, when residual adhesive from previous bonding is removed and enamel soda blasted.

  10. TCam-2 seminoma cells exposed to egg-derived microenvironment modify their shape, adhesive pattern and migratory behaviour: a molecular and morphometric analysis.

    Directory of Open Access Journals (Sweden)

    Francesca Ferranti

    Full Text Available Seminoma is one of the most common Testicular Germ Cell Tumours that originates during embryonic development due to an alteration of the local niche that in turn results in a delayed or blocked differentiation of Primordial Germ Cells. The block of differentiation is actually a common way to develop cancer disease as postulated by the "embryonic rest theory of cancer". In agreement with this theory different studies have demonstrated that embryonic cues display the capacity of reprogramming aggressive cancer cells towards a less aggressive phenotype. Herein we investigate the ability of a culture medium added with 10% egg albumen (EW, Egg White to modulate seminoma cell phenotype and behaviour, by ensuring a proper set of morphogenetic signals. We chose to use the TCam-2 seminoma cell line that has been established as the only available cell line, obtained from a primary testicular seminoma. EW is able to: 1 modify TCam-2 cell spreading rate and cell-substrate adhesion without affecting proliferation and survival indexes; 2 modulate TCam-2 actin distribution pattern increasing cortical localization of actin filaments; 3 increase TCam-2 cell-cell junction capability; 4 decrease both chemo-sensitive and collective TCam-2 migratory behaviour. According to these observations morphometric fractal analysis revealed the ability of EW to increase Circularity and Solidity parameters and, consequently, to decrease Fractal dimension. Prompted by these observations we hypothesize that EW treatment could rescue, at least in part, the neoplastic-metastatic behaviour of seminoma cells.

  11. Cement-latex grouting mortar for cementing boreholes

    Energy Technology Data Exchange (ETDEWEB)

    Kateev, I S; Golyshkina, L A; Gorbunova, I V; Kurochkin, B M; Vakula, Ya V

    1980-01-01

    The need for the development of cement-latex grouting mortar for the purpose of separating strata when reinforcing boreholes at deposits in the Tatar Associated SSR is evaluated. Results of studies of the physical and mechanical properties of cement-latex grouting mortar systems (mortar plus brick) are presented. Formulas for preparing cement-latex grouting mortor are evaluated and results of industrial tests of such mortars shown.

  12. Mechanical characterization of sisal reinforced cement mortar

    Directory of Open Access Journals (Sweden)

    R. Fujiyama

    2014-01-01

    Full Text Available This work aims at evaluating the mechanical behavior of sisal fiber reinforced cement mortar. The composite material was produced from a mixture of sand, cement, and water. Sisal fibers were added to the mixture in different lengths. Mechanical characterization of both the composite and the plain mortar was carried out using three point bend, compression, and impact tests. Specimens containing notches of different root radii were loaded in three point bending in an effort to determine the effect of the fibers on the fracture toughness of the material. The results obtained indicate that, while fiber reinforcement leads to a decrease in compressive strength, J-integral calculations at maximum load for the different notch root radii have indicated, particularly for the case of long fibers, a significant superiority of the reinforced material in comparison with the plain cement mortar, in consistence with the impact test data.

  13. Gas evolution behavior of aluminum in mortar

    Energy Technology Data Exchange (ETDEWEB)

    Hashizume, Shuji; Matsumoto, Junko; Banba, Tsunetaka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-10-01

    As a part of study of leaching behavior for solidified dry low level radioactive waste, gas evolution behavior of aluminum in mortar was investigated, and a plan of our research was proposed. The effect of pH on corrosion rate of aluminum, corrosion product, time dependency of corrosion rate of aluminum in mortar, change of corrosion mechanism, the effects of Na, Ca and Cl ions on corrosion rate of aluminum in mortar and corrosion behavior of aluminum when aluminum was used as sacrificed anode in reinforced concrete were previously clarified. Study of the effects of environmental factors such as pH, kind of ions and temperature on gas evolution behavior of aluminum and the effect of aluminum/carbon steel surface ratio no gas evolution behavior of aluminum were planed. (author). 75 refs.

  14. Gas evolution behavior of aluminum in mortar

    International Nuclear Information System (INIS)

    Hashizume, Shuji; Matsumoto, Junko; Banba, Tsunetaka

    1996-10-01

    As a part of study of leaching behavior for solidified dry low level radioactive waste, gas evolution behavior of aluminum in mortar was investigated, and a plan of our research was proposed. The effect of pH on corrosion rate of aluminum, corrosion product, time dependency of corrosion rate of aluminum in mortar, change of corrosion mechanism, the effects of Na, Ca and Cl ions on corrosion rate of aluminum in mortar and corrosion behavior of aluminum when aluminum was used as sacrificed anode in reinforced concrete were previously clarified. Study of the effects of environmental factors such as pH, kind of ions and temperature on gas evolution behavior of aluminum and the effect of aluminum/carbon steel surface ratio no gas evolution behavior of aluminum were planed. (author). 75 refs

  15. Stone mortars in Roman Cisalpine: new specimens

    Directory of Open Access Journals (Sweden)

    Andrea Caffini

    2010-07-01

    Full Text Available The mortar, made of stone or marble, represents artifact in Cisalpine widespread elsewhere in the Roman world. the morphologies are substantially grouped into two basic shapes: type 1 presents a hemispherical bowl more or less flattened, Type 2 is characterized by a conical reverse body, more or less flared. In the mortars were subjected to pounding and grinding, using a pestle driven by hand, raw materials of various origin. The fields of application were mainly three: alimentary, officinal and cosmetic. In some cases the generic definition of mortar is applied improperly to marble containers probably only be used for ornamental. It 'also demonstrated the use of artifacts attributable to type 2 as a function of urns. Therefore, in reference to decontextualized pieces, you should use a definition not unique, reflecting the different possible meanings of the artifact.

  16. Moisture transport over the brick/mortar interface

    NARCIS (Netherlands)

    Brocken, H.J.P.; Pel, L.

    1995-01-01

    The moisture transport in brick, mortar that was cured separately, and combined brick/mortar samples was studied using NMR. The experimental results show that the mortar is less permeable if it is cured bonded to the brick instead of cured separately. Models of the moisture transport are usually

  17. Influence of the mechanical properties of lime mortar on the strength of brick masonry

    OpenAIRE

    PAVIA, SARA

    2013-01-01

    PUBLISHED This paper aims at improving the quality of lime mortar masonry by understanding the mechanics of mortars and masonry and their interaction. It investigates how the mortar?s compressive and flexural strengths impact the compressive and bond strength of clay brick masonry bound with calcium lime (CL) and natural hydraulic lime (NHL) mortars. It concludes that the strength of the bond has a greater impact on the compressive strength of masonry than the mortar?s st...

  18. Compressive strength of brick masonry made with weak mortars

    DEFF Research Database (Denmark)

    Pedersen, Erik Steen; Hansen, Klavs Feilberg

    2013-01-01

    in the joint will ensure a certain level of load-carrying capacity. This is due to the interaction between compression in the weak mortar and tension in the adjacent bricks. This paper proposes an expression for the compressive strength of masonry made with weak lime mortars (fm... of masonry depends only on the strength of the bricks. A compression failure in masonry made with weak mortars occurs as a tension failure in the bricks, as they seek to prevent the mortar from being pressed out of the joints. The expression is derived by assuming hydrostatic pressure in the mortar joints......, which is the most unfavourable stress distribution with respect to tensile stresses in bricks. The expression is compared with the results of compression tests of masonry made with weak mortars. It can take into account bricks with arbitrary dimensions as well as perforated bricks. For a stronger mortar...

  19. Studies on diffusion of 137Cs in cement mortar

    International Nuclear Information System (INIS)

    Takebe, Shinichi; Shimooka, Kenji; Wadachi, Yoshiki; Kuramoto, Yuzuru.

    1989-12-01

    Penetration experiment of 137 Cs into the impermeable cement mortar which has been treated by the impermeable reagent (XYPEX reagent) was carried out in order to advance the performance of engineered barrier for Low Level Radioactive Waste. The result showed that the radioactive concentration at deeper region in the impermeable cement mortar specimen was decreased about 1 order of magnitude below that in the untreated specimen. Diffusion coefficient calculated from the radioactive concentration of 137 Cs in the cement mortar specimen was 9.1 x 10 -5 cm 2 /day for untreated cement mortar specimen and 4.0 x 10 -5 cm 2 /day for the impermeable cement mortar specimen, respectively. Treatment of cement mortar by the impermeable reagent was found to be effective to reduce the value of appearent diffusion coefficient for 137 Cs in the cement mortar. (author)

  20. 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...

  1. Gas generation from the irradiation of mortar

    International Nuclear Information System (INIS)

    Lewis, M.A.; Warren, D.W.

    1989-01-01

    A mortar formulation capable of immobilizing chloride salts with high levels of radioactivity is being developed. As part of the developmental effort, radiation effects are being investigated. The radiolytic generation of gas(es) from irradiated mortar formulations was determined for several formulations with variable salt loadings at several test temperatures. The irradiation of a mortar formulation consisting of cement, slag, fly ash, water and 0 to 10 wt % salt led to the generation of hydrogen. The rate of generation was approximately constant, steady state pressures were not attained and final pressures were comparatively high. Higher salt concentrations were correlated with higher hydrogen generation rates for experiments at ambient temperature while lower rates were observed at 120/degree/C. The irradiation of a mortar consisting of cement, fly ash, water and salt led to the radiolytic generation of both oxygen and hydrogen. The addition of 2 wt % FeS or CaS inhibited oxygen generation and changed the hydrogen production rate. 10 refs., 4 figs., 3 tabs

  2. Prediction models of mechanical properties for pet-mortar composite in sodium sulphateaggressive mediums

    Directory of Open Access Journals (Sweden)

    Kazi Tani Nabil

    2018-01-01

    Full Text Available In this research, an investigation was carried out on the effect of sodium sulphate attack on the durability of composites produced with waste polyethylene terephthalate (PET. Experiments were accomplished on limestone sand and cement mortars where the blended Portland cement was partially replaced by various volume fractions of waste PET particles (6%, 12% and 17%. The test solutions used to supply the sulphate ions and cations were 5%sodium sulphate solution. Compressive strengths measured on specimens were used to assess the changes in the mechanical properties of PET-mortars exposed to sulphate attack at different ages, mainly the Young modulus of elasticity. Based on experimental compressive tests on PETMortar composite specimens and there densities, the evolution of Young modulus of elasticity has been analyzed in accordance with normative models given by (ACI-318 and (BS-8110 codes of practice. In addition, a comparative study has been carried out for corrosion resistance coefficients K of unmodified mortar to those modified with waste PET particles. It can be noticed that, for the composite immersed in a corrosive Na2SO4 solution, the corrosion resistance coefficients decrease with the increase of the immersion period. The corrosion sulphate resistance K based on Young modulus before and after immersion of PET-mortar composites is better than that of the control mortar. Therefore, for safety considerations of PET-mortar composites use, ACI 318 is recommended code for design and investigation works. Also, it can be concluded that adding waste PET by volume fractions (6%, 12% and 17% to blend Portland cement renders this cement more resistant to the sodium sulphate aggressive medium. Therefore, composites materials based waste PET aare often presented as the materials of the future because of their potential for innovation and the advantages they offer. In fact, using waste PET as cement substitutes reduces the energy consumption. These

  3. Protein adhesives

    Science.gov (United States)

    Charles R. Frihart; Linda F. Lorenz

    2018-01-01

    Nature uses a wide variety of chemicals for providing adhesion internally (e.g., cell to cell) and externally (e.g., mussels to ships and piers). This adhesive bonding is chemically and mechanically complex, involving a variety of proteins, carbohydrates, and other compounds.Consequently,the effect of protein structures on adhesive properties is only partially...

  4. Syndecan proteoglycans and cell adhesion

    DEFF Research Database (Denmark)

    Woods, A; Oh, E S; Couchman, J R

    1998-01-01

    It is now becoming clear that a family of transmembrane proteoglycans, the syndecans, have important roles in cell adhesion. They participate through binding of matrix ligand to their glycosaminoglycan chains, clustering, and the induction of signaling cascades to modify the internal microfilament...... organization. Syndecans can modulate the type of adhesive responses induced by other matrix ligand-receptor interactions, such as those involving the integrins, and so contribute to the control of cell morphology, adhesion and migration....

  5. Evaluación de la adherencia de uniones adhesivas metálicas con adhesivos epoxídicos modificados Evaluation of the adherence of bonded metallic joints with modified epoxy adhesives

    Directory of Open Access Journals (Sweden)

    Filiberto González Garcia

    2008-03-01

    Full Text Available En este trabajo fueron evaluadas las propiedades adhesivas de la resina epoxídica del tipo éter diglicidílico del bisfenol A. La resina fue modificada con dos modificadores poliméricos, uno de ellos un copolímero derivado del butadieno, y el otro un copolímero acrílico con el propósito de aumentar la tenacidad de la resina. Tres aminas alifáticas primarias fueron utilizadas como agentes de curado, trietilentetramina, N-(2-aminoetilpiperazina e isoforondiamina. Las propiedades adhesivas fueron investigadas usando la resina pura, así como la resina modificada. Las propiedades adhesivas de la resina modificada y pura fueron estudiadas usando como adherente una aleación de acero (ASTM A36. La adherencia fue evaluada por ensayos de adhesión usando tres geometrías de uniones adhesivas de acero-acero. El comportamiento reológico de los adhesivos fue investigado en condiciones isotérmicas. Los parámetros reológicos relacionados con la reacción de polimerización tales como velocidad de reacción, tiempo de manipulación, y tiempo de gelación de los adhesivos puros fueron relacionados con la estructura química del agente de curado. El tiempo de separación de fases, y de gelación de los adhesivos modificados fue relacionado con la morfología generada, y con la velocidad de la reacción, respectivamente. La morfología fue caracterizada por microscopia electrónica de barrido. La adherencia de las uniones adhesivas sometidas a las diferentes solicitaciones mecánicas fue relacionada a la morfología generada por la fase dispersa de cada modificador, y con las estructuras de redes de los adhesivos.In this work the adhesive properties of epoxy resins based on diglycidyl ether of bisphenol A have been evaluated. The epoxy resin was modified with butadiene and acrylic copolymers to obtain toughened adhesives. The aliphatic primary amines triethylenetetramine, N-(2-aminoethylpiperazine and isophorone diamine were investigated as curing

  6. Plastering mortar with antibacterial and antifungal properties studied by 1H NMR relaxometry

    Science.gov (United States)

    Jumate, E.; Aciu, C.; Manea, D. L.; Moldovan, D.; Chelcea, R.; Fechete, R.

    2017-12-01

    The Plastering mortars, with good antibacterial (in particular Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa) and antifungal (Aspergillus niger and Penicillium chrysogenum) properties, were studied by 1D NMR relaxometry and internal humidity measurements. Three recipes based on plastering mortar with variable content (0, 5 and 10 %) of Ag/ZnO nanopowders and with adequate physical characteristics regarding the mechanical strengths (CS IV), good adhesion to the substrate and low water absorption by capillarity (W2) were considered. The distributions of transverse relaxation times T2 were measured at 2 h after preparation (for mortar pasta) and then for the same samples at 2, 7, and 28 days during the hydration of mineralogical components. The T2 distributions are characterized by four components associated with hydration water and water in three types of pores of different dimension. The dimension of pores formed during hydration process are strongly dependent on the Ag/ZnO nanopowders content but finally at 28 days the pores distributions, as resulted from the T2 distributions, looks similar. Finally, the transverse relaxation ratio was linearly correlated to the compressive strength and the hydration behaviour during 132 days measured with a dedicated humidity sensor embedded inside sampled was discussed.

  7. Design and properties of plaster mortars manufactured with ladle furnace slag

    International Nuclear Information System (INIS)

    Rodríguez, A.; Gutiérrez-González, S.; Horgnies, M.; Calderón, V.

    2013-01-01

    Highlights: • This study analyses plaster with ladle furnace slag as a mineral aggregate. • Tests are completed by characterizing the influences of two admixtures. • Microstructure, physical and mechanical results confirm the feasibility of these materials. • These new materials are potentially useful as plaster mortars for use in masonry. - Abstract: This study deals with the properties of a series of plasters containing different proportions of ladle furnace slag used as mineral aggregate. The tests characterise the influences of two admixtures: a superfluidifier to reduce the water absorption (SikaMix®) of mortar plaster and an adhesive emulsion to improve the surface adherence (SikaLatex®). The physical and mechanical results confirm the feasibility of employing ladle furnace slag as a mineral aggregate, which induces an increase in density, in vapour permeability and in porosity. The results highlight also a decrease of adherence, durability and mechanical strength, proportionally to the amount of plaster substituted by slag. Scanning electron microscopy imaging and elemental mapping show good interaction between the various constituents. The thermal degradation of the mixtures reflects an improvement in strength resistance in relation to temperature, as further slag is incorporated. The economical study suggests that these recycled materials are cost-effectively viable and may be applied as plaster mortars for use in masonry

  8. Orientation of Steel Fibers in Magnetically Driven Concrete and Mortar.

    Science.gov (United States)

    Xue, Wen; Chen, Ju; Xie, Fang; Feng, Bing

    2018-01-22

    The orientation of steel fibers in magnetically driven concrete and magnetically driven mortar was experimentally studied in this paper using a magnetic method. In the magnetically driven concrete, a steel slag was used to replace the coarse aggregate. In the magnetically driven mortar, steel slag and iron sand were used to replace the fine aggregate. A device was established to provide the magnetic force. The magnetic force was used to rotate the steel fibers. In addition, the magnetic force was also used to vibrate the concrete and mortar. The effect of magnetic force on the orientation of steel fibers was examined by comparing the direction of fibers before and after vibration. The effect of magnetically driven concrete and mortar on the orientation of steel fibers was also examined by comparing specimens to normal concrete and mortar. It is shown that the fibers could rotate about 90° in magnetically driven concrete. It is also shown that the number of fibers rotated in magnetically driven mortar was much more than in mortar vibrated using a shaking table. A splitting test was performed on concrete specimens to investigate the effect of fiber orientation. In addition, a flexural test was also performed on mortar test specimens. It is shown that the orientation of the steel fibers in magnetically driven concrete and mortar affects the strength of the concrete and mortar specimens.

  9. The influence of adding modified zirconium oxide-titanium dioxide nano-particles on mechanical properties of orthodontic adhesive: an in vitro study

    OpenAIRE

    Felemban, Nayef H.; Ebrahim, Mohamed I.

    2017-01-01

    Background The purpose of this in-vitro study was to examine the effect of incorporating different concentrations of Zirconium oxide-Titanium dioxide (ZrO2-TiO2) nanoparticles, which can have antibacterial properties, on the mechanical properties of an orthodontic adhesive. Methods ZrO2-TiO2 (Zirconium oxide, HWNANO, Hongwu International Group Ltd, China) -Titanium dioxide, Nanoshell, USA) nanopowder were incorporated into orthodontic adhesive (Transbond XT, 3?M Unitek, Monrovia, USA) with di...

  10. A new approach for enhancement of the corrosion protection properties and interfacial adhesion bonds between the epoxy coating and steel substrate through surface treatment by covalently modified amino functionalized graphene oxide film

    International Nuclear Information System (INIS)

    Parhizkar, N.; Shahrabi, T.; Ramezanzadeh, B.

    2017-01-01

    Highlights: •The steel substrate was treated by a covalently modified amino functionalized graphene oxide (fGO) film. •Deposition of fGO film at the interface of steel and epoxy could effectively improve the adhesion strength and corrosion protection properties. •More stable and stronger interfacial bonds was obtained when treating the interface by fGO film. -- Abstract: This study introduces a novel surface treatment approach of steel substrate by covalent modification of graphene oxide (fGO) nanosheets with 3-aminopropyltriethoxysilane to improve the adhesion and corrosion protection properties of an epoxy coating. The effect of fGO film on the epoxy coating performance was studied by field-emission scanning electron microscopy (FE-SEM), X-Ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), Pull-off adhesion, salt spray and cathodic delamination tests. Results revealed that deposition of fGO film on steel surface can effectively improve the adhesion strength and corrosion protection properties and reduce the cathodic delamination rate of the epoxy coating.

  11. 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.

  12. Development of low weight self-levelling mortars

    International Nuclear Information System (INIS)

    Padilla, A; Panama, I; Toledo, A; Flores, A

    2015-01-01

    This work shows the development of self levelling mortars, using micro bubbles based on aluminium silicate with a density of 0.25 g/cm 3 . Mortars formulations are composed by 8 different components in order to achieve properties balance between fresh and solid state. The mean objective is development light weight mortars with high fluidity and compression strength using micro bubbles and some additives. Formulations were designed employing Taguchi DOE of 8 variables and 3 states. Result analysis according to Taguchi method lets indentify the preponderant effect of each variable on the cited properties. Several formulations reached fluidity higher than 250%, with compression strength around 100 kg/cm 2 and a low volumetric weigh. Obtained volumetric weights are 20% less than commercial self levelling mortars weight. Finally some relations are presented such: as relation water/cement with fluidity, and micro bubble content versus mortars volumetric weight, and finally compression strength versus the volumetric weight of mortars

  13. Analysis of Bending Strength of Resin Mortars That Are at Risk of Long-Term Exposure to Environmental Corrosives

    Science.gov (United States)

    Debska, Bernardeta; Licholai, Lech

    2017-12-01

    The results of the article are part of an extensive research on new building materials including cement-free polymer composites where the binder is epoxy resin modified with glycolyzates obtained from poly (ethylene terephthalate) waste (PET). The investigation conducted con-firmed that there is a possibility of using waste materials in the production of mortar. Since they have always been an environmental problem, their utilization will help to apply the principles of sustainable development in the processes of obtaining new materials. The article discusses the results of a study of flexural strength of polymer mortars. Mortar specimens modified with propylene glycol and PET waste based glycolyzate were exposed to a 10% NaCl solution and their strength parameters were then examined after one month, six months and twelve months of immersion in this aggressive medium. The same characteristics were also determined for specimens that were not exposed to the NaCl solution. The results were presented as the trend function. The sections of the curve corresponding to the particular periods of exposure in aggressive medium vary in shape. Due to this, an attempt was made to adjust the spline function to the experimental data. The composites obtained show a deterioration in their strength properties which grows with the extension of their exposure to a corrosive medium. However, the chemical corrosion resistance of the mortars under investigation can be considered very good as it is still much higher than that of conventional cement mortars. Even after a year exposure to a corrosive substance, the mortars obtained still show high mean flexural strength values which equal about 30 MPa.

  14. Comparative evaluation of aerial lime mortars for architectural conservation

    OpenAIRE

    Faria, Paulina; Henriques, Fernando M.A.; Rato, Vasco

    2008-01-01

    Journal of Cultural Heritage 9 (2008) 338-346 International bibliography on conservation usually refers that mortars made with lime putty with long extinction periods behave better than others made with the current dry hydrated limes. In order to evaluate this assess, an experimental study of lime mortars was carried out, using dry hydrated lime and two lime putties. It becomes clear that the use of lime putties with long extinction periods in mortars allow better performances, pa...

  15. Study of mortars with industrial residual plastic scales

    OpenAIRE

    Magariños, O. E.; Alderete, C. E.; Arias, L. E.; Lucca, M. E.

    1998-01-01

    This work proposes the utilization of industrial residues of PET (Polyethylene Terephtalate) as a partial substitute of arids (sand) in mortar making for construction components. Therefore, the environmental impact of large volumes of plastic of urban residues could be decreased. When PET scales were added to mortars in partial replacement of sand, lower unitary weight, acceptable absorption and resistances according to international specifications were achieved. Mortars with 66% of sand...

  16. Moisture transfer across the interface between brick and mortar joint

    OpenAIRE

    Derluyn, Hannelore; Moonen, Peter; Carmeliet, Jan

    2008-01-01

    This paper reports on experimental and modelling work on moisture transport in masonry, with special attention to the liquid transport across the interface between brick and mortar joint. Experiments and simulations reveal that two aspects need to be taken into account: (1) the dependence of moisture transport properties on the curing of the mortar; (2) the presence of a hydraulic interface resistance between brick and mortar. The resistance is due to imperfect contact between brick and morta...

  17. 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...

  18. Characterization of backfill mortars used in different tunnels in Spain

    Directory of Open Access Journals (Sweden)

    Cavalaro, S.

    2013-03-01

    Full Text Available The main objective of this paper is to compare typical backfill mortars used in Spanish tunnels to fill the annular void left between the lining and the ground by the TBM. Initially, a new experimental program is outlined using material corresponding to 6 mixes from 4 tunnels. The results obtained indicate a considerable difference in the density and in the rheological properties of the mixes tested. According to the estimations performed, this leads to a difference of up to 67% on the potency required from the pumps to inject the material. Furthermore, a correlation between the fine content and the rheological properties of the mix was observed. This correlation may be a practical tool to control and modify the performance of the mortars directly in the worksite.

    El objetivo principal del presente estudio es llevar a cabo la comparación de las dosificaciones de mortero de relleno empleadas en algunos de los grandes túneles españoles para rellenar el hueco anular dejado entre el terreno y el extradós de las dovelas. Inicialmente se hace una nueva propuesta experimental usando la composición y los materiales correspondientes a 6 dosificaciones usadas en 4 túneles. Los resultados obtenidos indican diferencias significativas en cuanto a la densidad, a la consistencia y a las propiedades reológicas. De acuerdo con las estimaciones realizadas, ello se traduce en diferencias de hasta un 67% en la potencia requerida del sistema de bombas de la tuneladora para inyectar el material. Por otro lado, se refleja una correlación entre el contenido de finos de la mezcla y las propiedades reológicas. Esa correlación puede servir para controlar y modificar dichas propiedades de manera fácil y rápida a pie de obra.

  19. Cellular Adhesion and Adhesion Molecules

    OpenAIRE

    SELLER, Zerrin

    2014-01-01

    In recent years, cell adhesion and cell adhesion molecules have been shown to be important for many normal biological processes, including embryonic cell migration, immune system functions and wound healing. It has also been shown that they contribute to the pathogenesis of a large number of common human disorders, such as rheumatoid arthritis and tumor cell metastasis in cancer. In this review, the basic mechanisms of cellular adhesion and the structural and functional features of adhes...

  20. The influence of adding modified zirconium oxide-titanium dioxide nano-particles on mechanical properties of orthodontic adhesive: an in vitro study.

    Science.gov (United States)

    Felemban, Nayef H; Ebrahim, Mohamed I

    2017-01-13

    The purpose of this in-vitro study was to examine the effect of incorporating different concentrations of Zirconium oxide-Titanium dioxide (ZrO2-TiO2) nanoparticles, which can have antibacterial properties, on the mechanical properties of an orthodontic adhesive. ZrO2-TiO2 (Zirconium oxide, HWNANO, Hongwu International Group Ltd, China) -Titanium dioxide, Nanoshell, USA) nanopowder were incorporated into orthodontic adhesive (Transbond XT, 3 M Unitek, Monrovia, USA) with different concentrations (0.5% weight nonofiller and 1% weight nanofiller). The size of nanoparticle was 70-80 nm for ZrO2 and less than 50 nm for TiO2. For measuring the shear bond strength of the three groups of orthodontic adhesives [Transbond (control), Transbond mixed with 0.5% weight ZrO2-TiO2, and Transbond mixed with 1% weight ZrO2-TiO2], 30 freshly extracted human first premolars were used and bonded with stainless steel metal brackets (Dentaurum®, Discovery®, Deutschland), using the 3 orthodontic adhesives and 3 M Unitek; Transbond TM Plus Self-Etching Primer (10 samples in each group). The recorded values of compressive strength and tensile strength (measured separately on 10 samples of orthodontic adhesives (add the 3 D size of sample, light cured for 40 s on both sides) of each orthodontic adhesives), as well as the shear bond strength in Mega Pascal unit (MPa) were collected and exposed to one-way analysis of variance (ANOVA) and Tukey's post-hoc tests. orthodontic adhesive with 1% weight ZrO2-TiO2 showed the highest mean compressive (73.42 ± 1.55 MPa, p: 0.003, F: 12.74), tensile strength (8.65 ± 0.74 MPa, p: 0.001, F: 68.20), and shear bond strength (20.05 ± 0.2 MPa, p: 0.001, F: 0.17). Adding ZrO2-TiO2 nanoparticle to orthodontic adhesive increased compressive strength, tensile strength, and shear bond strength in vitro, but in vivo studies and randomized clinical trials are needed to validate the present findings.

  1. Adhesion science

    CERN Document Server

    Comyn, John

    1997-01-01

    The use of adhesives is widespread and growing, and there are few modern artefacts, from the simple cereal packet, to the jumbo jet, that are without this means of joining. Adhesion Science provides an illuminating account of the science underlying the use of adhesives, a branch of chemical technology which is fundamental to the science of coatings and composite materials and to the performance of all types of bonded structures. This book guides the reader through the essential basic polymer science, and the chemistry of adhesives in use at present. It discusses surface preparation for adhesive bonding, and the use of primers and coupling agents. There is a detailed chapter on contact angles and what can be predicted from them. A simple guide on stress distribution joints and how this relates to testing is included. It also examines the interaction of adhesives and the environment, including an analysis of the resistance of joints to water, oxygen and ultra-violet light. Adhesion Science provides a comprehens...

  2. Early age fracture properties of microstructurally-designed mortars

    DEFF Research Database (Denmark)

    Di Bella, Carmelo; Michel, Alexander; Stang, Henrik

    2017-01-01

    This paper compares the fracture properties as well as crack initiation and propagation of real and equivalent mortars. The development of the elastic modulus, tensile strength, and fracture energy at different hydration stages were determined by inverse analysis of load-displacement curves...... the two mortars. At early age, the moisture content has a considerable influence on the tensile strength and the fracture energy....

  3. Effects of water on mortar-brick bond

    NARCIS (Netherlands)

    Groot, C.J.W.P.

    1995-01-01

    The quality of bond in masonry is, to a large extent, a function of the (i) the hydration conditions and (ii) the mortar composition of the mortar-brick interface. For insight into the effects of these parameters on bond performance it is essential to dispose of quantitative information about water

  4. Advanced Experimental Evaluation of Asphalt Mortar for Induction Healing Purposes

    NARCIS (Netherlands)

    Apostolidis, P.; Liu, X.; Scarpas, Athanasios; van Bochove, G; van de Ven, M.F.C.

    2016-01-01

    This paper studied the induction heating and healing capacity of asphalt mortar by adding electrically conductive additives (e.g. iron powder and steel fibers), and examined the influence of different combinations of them on the mechanical response of asphalt mortars. Induction heating technique is

  5. Earth mortars and earth-lime renders

    Directory of Open Access Journals (Sweden)

    Maria Fernandes

    2008-01-01

    Full Text Available Earth surface coatings play a decorative architectural role, apart from their function as wall protection. In Portuguese vernacular architecture, earth mortars were usually applied on stone masonry, while earth renders and plasters were used on indoors surface coatings. Limestone exists only in certain areas of the country and consequently lime was not easily available everywhere, especially on granite and schist regions where stone masonry was a current building technique. In the central west coast of Portugal, the lime slaking procedure entailed slaking the quicklime mixed with earth (sandy soil, in a pit; the resulting mixture would then be combined in a mortar or plaster. This was also the procedure for manufactured adobes stabilized with lime. Adobe buildings with earth-lime renderings and plasters were also traditional in the same region, using lime putty and lime wash for final coat and decoration. Classic decoration on earth architecture from the 18th-19th century was in many countries a consequence of the François Cointeraux (1740-1830 manuals - Les Cahiers d'Architecture Rurale" (1793 - a French guide for earth architecture and building construction. This manual arrived to Portugal in the beginning of XIX century, but was never translated to Portuguese. References about decoration for earth houses were explained on this manual, as well as procedures about earth-lime renders and ornamentation of earth walls; in fact, these procedures are exactly the same as the ones used in adobe buildings in this Portuguese region. The specific purpose of the present paper is to show some cases of earth mortars, renders and plasters on stone buildings in Portugal and to explain the methods of producing earth-lime renders, and also to show some examples of rendering and coating with earth-lime in Portuguese adobe vernacular architecture.

  6. Brick mortar exposure and chronic lymphocytic leukemia.

    Science.gov (United States)

    Markovic-Denic, L; Jankovic, S; Marinkovic, J; Radovanovic, Z

    1995-01-01

    A case-control study of 130 patients with chronic lymphocytic leukemia (CLL) and 130 controls matched with respect to sex, age (2 years), type of residence (urban-rural) and area of residence (according to the national per capita income) was carried out. Conditional logistic regression analysis showed that, apart of four risk factors already described in the literature (work in a hazardous industry, hair dye use, family history of leukemia and exposure to electromagnetic radiation), brick mortar exposure was also significantly related to CLL.

  7. Brick mortar exposure and chronic lymphocytic leukemia

    International Nuclear Information System (INIS)

    Markovic-Denic, Lj.; Jankovic, S.; Marinkovic, J.; Radovanovic, Z.

    1995-01-01

    A case-control study of 130 patients with chronic lymphocytic leukemia (CLL) and 130 controls matched with respect to sex, age (2 years), type of residence, (urban-rural) and area of residence (according to the national per capita income) was carried out. Conditional logistic regression analysis showed that, apart of four risk factors already described in the literature (work in a hazardous industry, hair dye use, family history of leukemia and exposure to electromagnetic radiation), brick mortar exposure was also significantly related to CLL. (author)

  8. Brick mortar exposure and chronic lymphocytic leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Markovic-Denic, Lj; Jankovic, S [Institute of Epidemiology, Faculty of Medicine, Belgrade (Yugoslavia); Marinkovic, J [Institute of Social Medicine, Statistics and Healt Research, Faculty of Medicine, Belgrade (Yugoslavia); Radovanovic, Z [Department of Community Medicine and Behavioural Sciences, Faculty of Medicine, 13110 Safat (Kuwait)

    1996-12-31

    A case-control study of 130 patients with chronic lymphocytic leukemia (CLL) and 130 controls matched with respect to sex, age (2 years), type of residence, (urban-rural) and area of residence (according to the national per capita income) was carried out. Conditional logistic regression analysis showed that, apart of four risk factors already described in the literature (work in a hazardous industry, hair dye use, family history of leukemia and exposure to electromagnetic radiation), brick mortar exposure was also significantly related to CLL. (author) 1 tab., 30 refs.

  9. Dating mortars: three medieval Spanish architectures

    Directory of Open Access Journals (Sweden)

    Quirós Castillo, Juan Antonio

    2011-12-01

    Full Text Available One of the major issues in building archaeology is finding the age of elements and structures discovered. Mortars represent a class of material basically constituted by a mixture of different phases (i.e. binder, aggregates, water and are widely used for constructive uses and artworks. Current scientific literature regarding the possibility of accurate radiocarbon dating for mortars reports different and still contradictory results. In this study, a new protocol for radiocarbon dating of mortar developed at the Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE is used to perform 14C measurements on archaeological mortars coming from three medieval architectures of northern Spain (two churches and the walls of a castle. Results observed will be discussed and compared with independent age estimations (i.e. radiocarbon dating performed on organic materials found in the same study site, archaeological analyses in order to frame experimental observations in the actual site knowledge by means of a multidisciplinary approach.Una de las principales problemáticas a las que se enfrenta la arqueología de la arquitectura es datar los elementos y las estructuras. Las argamasas son un tipo de material constituido por una mezcla de diferentes elementos (agregados, agua y empleadas en muchos tipos de construcciones. Los estudios realizados hasta la actualidad en torno a la posibilidad de realizar dataciones radiocarbónicas precisas han proporcionado resultados contradictorios. El objetivo de este artículo es el de presentar un nuevo protocolo para datar la arquitectura histórica desarrollado por el Centre for Isotopic Research on Cultural and Enviromental Heritage (CIRCE, basado en la realización de dataciones radiocarbónicas de argamasas a partir del análisis de tres arquitecturas medievales del norte del España, dos iglesias y la muralla de un castillo. Los resultados obtenidos han sido confrontados y comparados con otros

  10. Luminescence quartz dating of lime mortars. A first research approach

    International Nuclear Information System (INIS)

    Zacharias, N.; Mauz, B.; Michael, C.T.

    2002-01-01

    Lime mortars mixed with sand are well suited for connecting structural materials, like stones and bricks, due to the mechanical properties this material exhibits. Their extensive use in architectural and decorative works during the last 4000 years motivated the introduction of the 'Luminescence clock' for age determination of mortars. The same principles as for quartz optically stimulated luminescence (OSL) dating of sediments were applied for age estimation of a mortar fragment removed from a Byzantine church monument dated by archaeological means to 1050-1100 years ago (the first half of the 10th century). The OSL from the quartz was monitored under blue light stimulation and UV detection, using a single-aliquot-regenerative-dose protocol. The quartz-OSL dating of the mortar resulted in 870±230 a. TL polymineral fine grain dating was also performed on a brick fragment which was connected to the mortar, resulting in a TL age of 1095±190 a. (author)

  11. Adhesive Bonding and Corrosion Performance Investigated as a Function of Aluminum Oxide Chemistry and Adhesives

    NARCIS (Netherlands)

    Abrahami, S.T.; Hauffman, T.; de Kok, John M.M.; Terryn, H.A.; Mol, J.M.C.

    2017-01-01

    The long-term strength and durability of an adhesive bond is dependent on the stability of the oxide-adhesive interface. As such, changes in the chemistry of the oxide and/or the adhesive are expected to modify the interfacial properties and affect the joint performance in practice. The upcoming

  12. RILEM TC 203-RHM: Repair mortars for historic masonry The role of mortar in masonry: an introduction to requirements for the design of repair mortars

    Czech Academy of Sciences Publication Activity Database

    Groot, C.; van Balen, K.; Bicer-Simsir, B.; Binda, L.; Elsen, J.; van Hees, R.; von Konow, T.; Lindqvist, J.; Mauerbrecher, P.; Papayanni, I.; Subercaseaux, M.; Tedeschi, C.; Toumbakari, E.; Thompson, M.; Válek, Jan; Veiga, R.

    2012-01-01

    Roč. 45, č. 9 (2012), s. 1287-1294 ISSN 1359-5997 Institutional support: RVO:68378297 Keywords : mortar * classification * requirements Subject RIV: JN - Civil Engineering Impact factor: 1.184, year: 2012

  13. Effect of high temperature and type of cooling on some mechanical properties of cement mortar

    Directory of Open Access Journals (Sweden)

    Abdulhussei Faisal

    2018-01-01

    Full Text Available Mortar of cement as construction materials subjected sometimes to high temperature. Some of properties of this mortar being studied after this effect. The effect of high temperature 100, 200, 400 and 700°C (exposed for two hrs. on some mechanical properties (compressive and flexural strength of two groups of cement mortar samples (with and without the addition of crushed bricks and superplasticizer as modifying materials has been studied. Two methods of cooling samples by air and by water for 1/2 hr. was used, then tested after 3, 7 and 28 days. The results showed that the compressive and flexural strength for reference mix exposed to 700°C and water cooling decreased by 65.3 % and 64.7%, respectively, compared with their reference mix tested at 20°C in 28 days. While mixes containing 100% of crushed brick as an additive and air cooling decreases by 12.3% and 9% of their compressive and flexural strength, respectively compared with the mixes tested at 20°C in 28 days. Also showed that the decreases in flexural strength for no sand mixes containing 100% of crushed brick and 4% of superplasticizer exposed to 700°C and then water cooling was 28.2% compared to those for reference mixes tested at 20°C.

  14. Tamping Mortars with Stabilizing and Plasticizing Admixtures

    Science.gov (United States)

    Terlyha, Volodymir; Sobol, Khrystyna

    2012-06-01

    Boreholes cementing operations at the depth of several kilometers requires the best technology as well as the best materials. To produce the materials satisfying all the requirements concerning the tamping works is possible using the technology of dry building mixes (DBM) prepared at the factories by thorough mixing of accurately dosed components. Using of chemical admixtures allows improving some properties of these mixes. In this work the influence of mineral fillers and chemical admixtures on the properties of the fresh mixture and hardened tamping mortar was investigated. It is established that introduction of the admixture with complex action on the basis of stabilizer Walocel 15-01 and plasticizer Melflux 2651 allows obtaining the fresh mixture with high spreadability. At the same time the value of dehydration approaches to zero which favorably effects on stabilization of fresh mixture and not allows the sedimentation processes to take place. By the X-ray analysis, the positive influence of modification admixtures on the hydration processes in the tamping mortars by activating them was identified. In the result of this, the formation of hydrate phases is accelerated; these phases tightly mud the pore area of tamping stone increasing by this its strength.

  15. Project of law authorizing the adhesion to the protocol of 1997 modifying the international convention of 1973 for the prevention of the pollution by ships, such as modified by the related protocol of 1978; Projet de loi autorisant l'adhesion au protocole de 1997 modifiant la convention internationale de 1973 pour la prevention de la pollution par les navires, telle que modifiee par le protocole de 1978 y relatif

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-04-01

    The first international agreement of May 12, 1954, for the protection of the marine and coastal environments against pollution was replaced on November 2, 1973 by a more detailed convention for the prevention of the pollution by ships. The 25 rules defined in the appendix 1 of this last document were modified and completed by the protocol of February 17, 1978. To make this system even more constraining for the atmospheric pollution, a diplomatic conference took place in September 1997 at the head office of the international maritime organization in London (UK). This conference has adopted a protocol which introduced a new appendix no. 6 in the text of the 1973 convention for the abatement of the emissions of sulfur compounds and other polluting combustion products in case of oil-tank burning. This document is a project of law authorizing the adhesion of France to the protocol of 1997. It summarizes the main content of the articles of this protocol, and in particular the rules introduced in the new appendix. The full text of the protocol and of its appendixes are also attached. (J.S.)

  16. Environmental deterioration of ancient and modern hydraulic mortars (EDAMM)

    Energy Technology Data Exchange (ETDEWEB)

    Van Balen, K.; Toumbakari, E.E.; Blanco-Varela, M.T. (and others) (eds.)

    2002-07-01

    Environmental damage to ancient and modern mortars (EDAMM) is a European Commission funded project in which three European research institutes from Belgium, Spain and Italy have been collaborating. The project has provided a better understanding of the role of environmental pollution on the deterioration of ancient and modern hydraulic mortars. Recent monuments built in the 19th and 20th century, were constructed using these types of hydraulic mortars. Increasing numbers of these monuments need restoration all over Europe. Similar hydraulic mortars have been widely used in treatments carried out during last and the present century. Tests have been carried out on the identification of historic hydraulic mortars, on the evaluation of damage on samples taken from historic buildings and on the laboratory simulations carried out to investigate damage mechanisms. Among pollutants, SO{sub 2} is the main component of pollution causing damage to hydraulic mortars. Hydraulic mortars have been identified as the most sensitive building materials because of the formation of primary and secondary damage products, such as ettringite and thaumasite. Although the important implications of these results are for the development of conservation strategies for monuments and historic buildings, they are also of great relevance to the development of sustainable construction methods as the building industry still uses these materials today.

  17. Experiments on moisture form of concrete and adhesion of paints

    International Nuclear Information System (INIS)

    Kita, Daizo; Sumino, Masahiro

    1975-01-01

    It is necessary for radiation-resisting paints to adhere tightly to concrete in order to exhibit superior effects. As adhesion of paints to concrete is greatly affected by moisture content of concrete, this content is checked severely in the field. However, it may be considered that adhesion will be affected by the form of the moisture in the concrete also. Therefore, experiments were conducted with mortar to investigate the interrelations between pF-moisture content, moisture form and adhesion of paint. The following results were obtained: 1) Adhesion of paint becomes stronger as moisture content falls. 2) Adhesion strength of paint rises sharply until moisture content falls to a pF-value of 5.5 after which the strength is increased gradually until moisture content reaches pF of 7.0. 3) The pF-moisture content of 5.5 varies greatly depending on the mix proportions of mortar, but the form of moisture in such cases remains fixed and unchanged. (auth.)

  18. Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

    Science.gov (United States)

    Razavizadeh, Mahmoud; Jamshidi, Masoud

    2016-08-01

    Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

  19. Applying a biodeposition layer to increase the bond of a repair mortar on a mortar substrate

    OpenAIRE

    Snoeck, Didier; Wang, Jianyun; Bentz, D. P.; De Belie, Nele

    2018-01-01

    One of the major concerns in infrastructure repair is a sufficient bond between the substrate and the repair material, especially for the long-term performance and durability of the repaired structure. In this study, the bond of the repair material on the mortar substrate is promoted via the biodeposition of a calcium carbonate layer by a ureolytic bacterium. X-ray diffraction and scanning electron microscopy were used to examine the interfaces between the repair material and the substrate, a...

  20. Tensile capacity of loop connections grouted with concrete or mortar

    DEFF Research Database (Denmark)

    Sørensen, Jesper Harrild; Hoang, Linh Cao; Olesen, John Forbes

    2017-01-01

    This paper presents a study of grout failure in symmetric U-bar loop connections loaded in tension, with focus on the performance of two grouting materials – concrete and mortar. The study contains an experimental investigation as well as a rigid-plastic modelling of the tensile capacity. The test...... to allow yielding of the U-bars. The experimental work showed that connections grouted with concrete performed better than the connections grouted with mortar. In the theoretical models, the difference in tested capacity is explained by the difference in the internal angle of friction and in the softening...... behaviour of concrete as compared with mortar....

  1. 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.

  2. Comparative investigation of mortars from Roman Colosseum and cistern

    International Nuclear Information System (INIS)

    Silva, D.A.; Wenk, H.R.; Monteiro, P.J.M.

    2005-01-01

    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

  3. Radiocarbon dating of mortars from ancient Greek palaces

    International Nuclear Information System (INIS)

    Zouridakis, N.; Saliege, J.F.; Person, A.; Filippakis, S.E.

    1987-01-01

    The study deals with radiocarbon dating of lime mortars which were used as supports for Mycenaean and Minoan paintings. The 14 C dates are, on the whole, compatible with the historical data, and thus show that a large proportion of the Mycenaean surficial coatings can be dated by the radiocarbon method. However, in order to determine the age of the mortars accurately, it is necessary to evaluate the amount of sedimentary carbonate which may have been added to them. It is shown here that the oxygen and carbon isotope compositions of lime mortars are significant indicators that such a mixing actually took place. (author)

  4. Radiocarbon dating of mortars from ancient Greek palaces

    Energy Technology Data Exchange (ETDEWEB)

    Zouridakis, N.; Saliege, J.F.; Person, A.; Filippakis, S.E.

    1987-02-01

    The study deals with radiocarbon dating of lime mortars which were used as supports for Mycenaean and Minoan paintings. The /sup 14/C dates are, on the whole, compatible with the historical data, and thus show that a large proportion of the Mycenaean surficial coatings can be dated by the radiocarbon method. However, in order to determine the age of the mortars accurately, it is necessary to evaluate the amount of sedimentary carbonate which may have been added to them. It is shown here that the oxygen and carbon isotope compositions of lime mortars are significant indicators that such a mixing actually took place.

  5. Test Method for Rheological Behavior of Mortar for Building Work

    Directory of Open Access Journals (Sweden)

    Korobko Bogdan

    2017-09-01

    Full Text Available This paper offers a test method for rheological behavior of mortars with different mobility and different composition, which are used for execution of construction work. This method is based on investigation of the interaction between the valve ball and the mortar under study and allows quick defining of experimental variables for any composition of building mortars. Certain rheological behavior will permit to calculate the design parameters of machines for specific conditions of work performance – mixing (pre-operation, pressure generation, pumping to the work site, workpiece surfacing.

  6. Composition of mortar as a function of distance to the brick-mortar interface : A study on the formation of cured mortar structure in masonry using NMR, PFM and XRD

    NARCIS (Netherlands)

    Brocken, H.J.P.; Larbi, J.A.; Pel, L.; Pers, N.M. van der

    1999-01-01

    The formation of cured mortar structure in masonry was studied using multiple experimental techniques. Starting with fresh mortar, nuclear magnetic resonance (NMR) was used to measure the water extraction during brick laying. After curing, the composition of cured mortar was investigated with

  7. Adhesion molecules

    CERN Document Server

    Preedy, Victor R

    2016-01-01

    This book covers the structure and classification of adhesion molecules in relation to signaling pathways and gene expression. It discusses immunohistochemical localization, neutrophil migration, and junctional, functional, and inflammatory adhesion molecules in pathologies such as leukocyte decompression sickness and ischemia reperfusion injury. Highlighting the medical applications of current research, chapters cover diabetes, obesity, and metabolic syndrome; hypoxia; kidney disease; smoking, atrial fibrillation, and heart disease, the brain and dementia; and tumor proliferation. Finally, it looks at molecular imaging and bioinformatics, high-throughput technologies, and chemotherapy.

  8. Aired-time and chamotte hydraulic mortars

    Directory of Open Access Journals (Sweden)

    González Cortina, M.

    2002-06-01

    Full Text Available The aim of this research project has been to obtain aired-li me based hydraulic mortars with the addition of chamotte or burnt clay powder obtained from the ceramic industry waste. By doing this, hydraulic properties have been included into lime and hydraulic mortars with a great improvement in mechanical properties. In order to achieve this, different types of chamotte obtained from clay burnt at different temperatures have been tested, changing, at the same time, the proportions of lime, sand, chamotte and water. All the tests have been performed preparing a double set of test pieces to be kept at room temperature or to be immersed in water, determining the Shore C hardness and the mechanical compressive and tensile strengths. Further on, X-ray diffraction analysis have been developed to determine the qualitative composition of the crystalline structure, as well as micro structural analysis, using stereomicroscope and electric microscope scanning, with X-ray microanalysis have been used. As a conclusion, several types of mortars have been created with different proportions, which can be used, due to its characteristics, as keying mortars in brickwork, for restoration works as well as for new constructions.

    El objetivo de éste trabajo es el conseguir morteros hidráulicos, a partir de la cal aérea, con adición de chamota o polvo de arcilla cocida, obtenida de los residuos-desechos de la industria cerámica. De este modo se pretende infundir propiedades hidráulicas a la cal y obtener morteros hidráulicos, con una mejora sustancial de sus propiedades mecánicas. Para ello, se ha experimentado con diversos tipos de chamotas, obtenidas a partir de arcillas cocidas a diferentes temperaturas, y con diversas granulometrías, y se han realizado morteros con distintas dosificaciones, variando las proporciones de cal, arena, chamota y agua. En todos los casos se ha preparado una doble serie de probetas, para conservarlas al aire o

  9. Hospital waste ashes in Portland cement mortars

    International Nuclear Information System (INIS)

    Genazzini, C.; Zerbino, R.; Ronco, A.; Batic, O.; Giaccio, G.

    2003-01-01

    Nowadays, most concretes incorporate mineral additions such as pozzolans, fly ash, silica fume, blast furnace slag, and calcareous filler among others. Although the technological and economical benefits were the main reasons for the use of mineral additions, the prevention of environmental contamination by means of proper waste disposal becomes a priority. The chance of incorporating hospital waste ashes in Portland cement-based materials is presented here. Ash characterization was performed by chemical analysis, X-ray diffraction, radioactive material detection, and fineness and density tests. Conduction calorimetry and setting time tests were developed on pastes including ash contents from 0% to 100%. Mortars were prepared including ash contents up to 50% of cement. The results of setting time, temperature development, flexural and compressive strengths, water absorption, density, and leachability are analyzed. Results indicate that Portland cement systems could become an alternative for the disposal of this type of ashes

  10. Immobilization of IFR salt wastes in mortar

    International Nuclear Information System (INIS)

    Fisher, D.F.; Johnson, T.R.

    1988-01-01

    Portland cement-base mortars are being considered for immobilizing chloride salt wastes from the fuel cycle of an integral fast reactor (IFR). The IFR is a sodium-cooled fast reactor with metal fuel. It has a close-coupled fuel cycle in which fission products are separated from the actinides in an electrochemical cell operating at 500 degrees C. This cell has a cadmium anode and a liquid salt electrolyte. The salt will be a low-melting mixture of alkaline and alkaline earth chlorides. This paper discusses one method being considered for immobilizing this treated salt, to disperse it in a portland cement-base motar, which would then be sealed in corrosion-resistant containers. For this application, the grout must be sufficiently fluid that it can be pumped into canisters where it will solidify into a strong, leach-resistant material

  11. Mortar alteration: experimental study and ancient analogues

    International Nuclear Information System (INIS)

    Rassineux, Francois

    1987-01-01

    As the durability of cemented matrices is a matter of great importance in numerous domains, notably for the long term reliability of surface storages of radioactive wastes, the objective of this research thesis is to define mechanisms of evolution of cemented matrices when in contact with diluted aqueous solutions. The author notably studied the influence of the lixiviation mode on the evolution of two mortars having different compositions (pH, CO 2 pressure, system containment, and cement mineralogical nature appear to be the main governing parameters), the alteration (dissolution is the prevailing process in the interaction between cemented matrices and a diluted solution such as rain water), and ancient binders (archaeological binders containing mineral phases such as hydrated calcium silicates or hydro-grossulars). The obtained results lead to the definition of alteration mechanisms in modern cements, and highlight factors governing the durability of these materials when submitted to meteoric alteration [fr

  12. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    , which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...... tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters...

  13. A multiscale mortar multipoint flux mixed finite element method

    KAUST Repository

    Wheeler, Mary Fanett; Xue, Guangri; Yotov, Ivan

    2012-01-01

    In this paper, we develop a multiscale mortar multipoint flux mixed finite element method for second order elliptic problems. The equations in the coarse elements (or subdomains) are discretized on a fine grid scale by a multipoint flux mixed finite

  14. Repair mortars based on lime. Accelerated aging tests

    Directory of Open Access Journals (Sweden)

    Martínez-Ramírez, S.

    1995-06-01

    Full Text Available The behaviour under different accelerated aging tests (freeze/thaw and crystallization cycles of a new lime mortar with biocide properties destinated to monumental repair has been studied. New mortars (which have the biocide impregnated in a clay called sepiolite have a similar behaviour to lime mortars used as a reference. After the aging tests, the biocide properties of the mortars have been tried.

    Se ha estudiado el comportamiento frente a distintos ensayos de envejecimiento acelerado (ciclos de hielo/deshielo y cristalización de sales de un nuevo mortero de cal con propiedades biocidas, destinado a la reparación monumental. Se ha comprobado que los nuevos morteros (que llevan incorporado el biocida impregnado en una arcilla denominada sepiolita tienen un comportamiento muy similar a los morteros de cal utilizados como referencia. Tras los ensayos de envejecimiento se ha visto que las propiedades biocidas de los morteros se mantienen.

  15. Future Combat Systems (FCS) Creates Cannon and Mortar Synergy

    National Research Council Canada - National Science Library

    Beard, Kirby; James, Jeff; Tolbert, Vincent J

    2008-01-01

    .... The NLOS-C is one of the eight MGVs. Program Manager FCS (Brigade Combat Team (PM FCS(BCT)) is leveraging previous and current research and development efforts to create synergy between cannons and mortars, without duplication of effort...

  16. compressive and flexural strength of cement mortar stabilized with ...

    African Journals Online (AJOL)

    PROF. BARTH EKWEME

    concrete. However, plain mortar materials are usually brittle and often crack more easily and fail more suddenly than ... impact strength, higher elastic modulus, better sound proofness ..... in Concrete. Unpublished Ph.D. Thesis, Department.

  17. The Provisional Irish Republican Army and the Development of Mortars

    Directory of Open Access Journals (Sweden)

    Gary Ackerman

    2016-03-01

    Full Text Available The Provisional Irish Republican Army (PIRA repeatedly showed itself to be one of the most inventive and adaptive of all the violent non-state actors who operated in the latter part of the twentieth century. Among its most innovative exploits was the PIRA’s successful development and fielding – spanning almost its entire operational lifetime – of improvised mortar systems. This chapter will trace the sustained development of mortars, including the underlying motivations for pursuing mortars as a complex engineering effort, the process by which the development took place and the underpinnings of its success. The discussion will show that the PIRA’s mortar development program was born out of tactical necessity but enabled by good organizational practices and the organization’s access to materials, expertise and places in which to leverage these.

  18. A Study of Array Direction HDPE Fiber Reinforced Mortar

    Science.gov (United States)

    Kamsuwan, Trithos

    2018-02-01

    This paper presents the effect of array direction HDPE fiber using as the reinforced material in cement mortar. The experimental data were created reference to the efficiency of using HDPE fiber reinforced on the tensile properties of cement mortar with different high drawn ratio of HDPE fibers. The fiber with the different drawn ratio 25x (d25 with E xx), and 35x (d35 with E xx) fiber volume fraction (0%, 1.0%, 1.5%) and fiber length 20 mm. were used to compare between random direction and array direction of HDPE fibers and the stress - strain displacement relationship behavior of HDPE short fiber reinforced cement mortar were investigated. It was found that the array direction with HDPE fibers show more improved in tensile strength and toughness when reinforced in cement mortar.

  19. A chemometric approach to the characterisation of historical mortars

    International Nuclear Information System (INIS)

    Rampazzi, L.; Pozzi, A.; Sansonetti, A.; Toniolo, L.; Giussani, B.

    2006-01-01

    The compositional knowledge of historical mortars is of great concern in case of provenance and dating investigations and of conservation works since the nature of the raw materials suggests the most compatible conservation products. The classic characterisation usually goes through various analytical determinations, while conservation laboratories call for simple and quick analyses able to enlighten the nature of mortars, usually in terms of the binder fraction. A chemometric approach to the matter is here undertaken. Specimens of mortars were prepared with calcitic and dolomitic binders and analysed by Atomic Spectroscopy. Principal Components Analysis (PCA) was used to investigate the features of specimens and samples. A Partial Least Square (PLS1) regression was done in order to predict the binder/aggregate ratio. The model was applied to historical mortars from the churches of St. Lorenzo (Milan) and St. Abbondio (Como). The accordance between the predictive model and the real samples is discussed

  20. 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

  1. 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.

  2. Mørtelegenskaber og billedbehandling (Mortar properties and image processing)

    DEFF Research Database (Denmark)

    Nielsen, Anders

    1998-01-01

    The properties of lime mortars can be essentially improved by adding fillers to the mortars in an intelligent way. This is shown in the thesis of Thorborg von Konow (1997).The changes in the pore structure and the following changes in properties can be treated by means of the rules in materials m...... mechanics developed by Lauge Fuglsang Nielsen on this institute. The necessary pore characteristics are measured by means of image processing....

  3. Syndecan-4 and focal adhesion function

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    2001-01-01

    Two groups have now reported the viability of mice that lack syndecan-4. These mice have wound healing/angiogenesis problems, and fibroblasts from these animals differ in adhesion and migration from normal. This is consistent with recent in vitro data indicating a need for signaling via syndecan-4...... for focal adhesion formation, and reports that overexpression of proteins that bind syndecan-4 can modify cell adhesion and migration....

  4. Evaluation of the antimicrobial and physical properties of an orthodontic photo-activated adhesive modified with an antiplaque agent: An in vitro study

    Directory of Open Access Journals (Sweden)

    Chanjyot Singh

    2013-01-01

    Results: The findings indicated that (1 addition of chlorhexidine to the orthodontic composite resin enhanced its antimicrobial properties, (2 there was no significant difference between the bond strengths of the control and the experimental resins tested after 24 h and 25 days and (3 maximum release of chlorhexidine from the modified resin was much higher than the minimum inhibitory concentration level.

  5. Applicability of Carbonated Electric Arc Furnace Slag to Mortar

    International Nuclear Information System (INIS)

    Yokoyama, S; Izaki, M; Arisawa, R; Hisyamudin, M N N; Murakami, K; Maegawa, A

    2012-01-01

    Authors have been studying the absorption of CO 2 in the steelmaking slag. In this study, an application of the electric arc furnace slag after the carbonation to admixture of mortar was investigated with the JIS (A6206-1997) method for ground granulated blast-furnace slag for concrete. The percent flows for the test mortar were smaller than that for the standard mortar. The percent flow of the carbonated slag whose average particle size of more than approximately 4 μm increased with an increase in the average size of the particles. Because the compressive strengths of the test mortar cured for 91 days were almost the same as those cured 28 days, the slag after the carbonation was thought not to have self-hardening property for a medium and long term. The compressive strength for the test mortar was almost unchanged within a range of approximately 2 to 7 μm of the average particle size, and it in this range was highest. The activity indexes for the test mortar prepared with the slag after the carbonation ranged from approximately 40 to 60%.

  6. 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.

  7. 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.

  8. 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

  9. The Impact of Additive on the Properties of Fresh and Hardened Mortar

    Directory of Open Access Journals (Sweden)

    Jurga Šeputytė

    2012-11-01

    Full Text Available This paper considers the impact of additives on the properties of mortar. For investigation purposes, two types of Portland cement (CEM II/A-LL 42.5 N and CEM I N (MA, fine aggregate sand, lime, water and air-entraining and stabilizing additives were used. To determine the effects of additives on the mortar mix, the analysis of cone penetration into the mix, mortar mobility, water extraction out of mortar, density and flexural and compressive testing were conducted. When put into mortar, air-entraining and stabilizing additives changed structure. In this case, density and flexural and compressive strength of mortar are reduced.

  10. Microleakage of class V cavities restored with nanofilled resin modified glass ionomer and conventional glass ionomer with self etch adhesive and self etch primer

    Directory of Open Access Journals (Sweden)

    Mansore Mirzaie

    2016-03-01

    Full Text Available Background and Aims: Microleakage is a criterion proposed for assessing the success of any restorative material. Complete seal is difficult especially for dentin margins compared to enamel margins. The aim of this study was to assess the microleakage at the enamel and dentin margins of class V cavities restored by two GIs and two self-etch adhesive systems. Materials and Methods: This study was done on forty third molars. Class V cavities (3×2×2mm were prepared on the buccal and lingual surfaces of teeth using high speed handpiece with 0.8 mm diamond fissure burr. The occlusal margins of the cavities in the enamel and gingival marginswere placed 1 mm below the CEJ. The teeth were divided into 4 groups and the bondings were cured for 20 sec and the teeth were restored. The specimens were kept in distilled water at the temperature of 37°C for 24 hrs. The teeth were thermo cycled and cut in buccolingual direction using diamond disc under water. The dye penetration was evaluated using a stereomicroscope and the leakage was scored. The scores were compared using Kruskal-Wallis test while the paired comparisons were done using Bonferroni correction. P≤0.05 was regarded as significant results. Results: Microleakage scores were similar at the occlusal and gingival walls of all test groups. At the gingival walls, the least microleakage scores were observed. “Fuji IX + SE bond” group showed significant differences with the “Fuji IX + G bond” and “Nanoglass + G bond” groups (P≤0.05. At the occlusal walls, the least scores were observed in the “Fuji IX+SE bond” specimens which were significantly different from the other groups (P≤0.05. Conclusion: Self-Cure glass ionomers yielded less microleakage scores compared to the different types of light-cures due to the less polymerization shrinkage.

  11. The effect of fly ash on the quality of mortars

    Energy Technology Data Exchange (ETDEWEB)

    Hovy, M F [Blue Circle Cement (Pty) Ltd., Industria West (South Africa)

    1994-12-31

    A comparative study of the commercially available blends of the fly cement was made. The focus of the research was to determine the suitability of fly ash blends in mortars. A comparative evaluation was made to establish the differences between laboratory analysis and on site practice. These comparisons were made using 4 different building sands. The laboratory evaluations were confined to specified test methods to determine the suitability of the mortar. However, the in-situ tests required an innovative approach such as: conducting tests on mortar joints to determine the in-situ compressive strengths. (A new technique was developed, which involves shooting nails into the mortar joint, determining the penetration depth and its pull out strength. This is then calibrated against cube strengths); and conducting tests using the SABS approach to determine the resistance to water penetration through a brick wall. The trends in the laboratory evaluations were as expected in terms of improved water demands, water retention and reduced compressive strengths. The in-situ mortar compressive strengths were marginally lower when using fly ash blends compared to ordinary portland cement. The use of fly ash blends improved the resistance of water penetration through a brick wall. In-situ tests are probably the only meaningful way to determine the effectiveness of a mortar in fulfilling its functions in a wall as laid down by SABS 0164:1990. With this in mind, the same quality or an improved quality mortar will be obtained using fly ash blended cements rather than ordinary portland cement. 10 refs., 13 figs., 5 tabs.

  12. Sulfur-free lignins from alkaline pulping tested in mortar for use as mortar additives.

    Science.gov (United States)

    Nadif, A; Hunkeler, D; Käuper, P

    2002-08-01

    Sulfur-free lignin, obtained through the acid precipitation of black liquor from the soda pulping process, has been tested as water reducer in mortar. It has also been compared to existing commercial additives such as naphthalene sulfonates and lignosulfonates. The ash content and sugar content of these lignins are low in comparison to lignosulfonates, conferring on them higher purity. A procedure for small scale testing derived from the industrial norms SN-EN196 and ASTM (Designation C230-90) is presented. Specifically, all the sulfur-free lignins tested improved the flow of the mortar. Selected flax lignins performed better than lignosulfonates though still less than naphthalene sulfonates. Furthermore, certain hemp lignins gave comparable results to the lignosulfonates. Overall, the straw lignin prepared herein is comparable in performance to commercially available lignins, such as Organocell, Alcell and Curan 100. The plant from which the lignin was isolated, and the process of the pulp mill are the primary influences on the performance of the lignin.

  13. Rilem TC 203-RHM. Repair mortars for historic masonry. The role of mortar in masonry: an introduction to requirements for the design of repair mortars

    NARCIS (Netherlands)

    Hees, R.P.J. van; Groot, C.; Balen, K. van; Bicer-Simsir, B.; Binda, L.; Elsen, J.; Konow, T. von; Lindqvist, J.E.; Maurenbrecher, P.; Papayanni, I.; Subercaseaux, M.; Tedeschi, C.; Toumbakari, E.E.; Thompson, M.

    2012-01-01

    Mortar has been in use for many thousands of years and is integral to most masonry construction. Its use is widespread in every culture where masonry is constructed. It is present in the majority of the global built cultural heritage, and is therefore a major consideration in building conservation.

  14. 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.

  15. MODIFICATION OF FOAMED CEMENT-CLAY MORTARS BY STABILIZERS

    Directory of Open Access Journals (Sweden)

    Panfilova Marina Ivanovna

    2012-10-01

    by-product generated in the course of combustion of crossties, and reduction of the cement consumption rate. The authors have identified that ash added into the injection does not cause any deterioration of the mortar strength; rather, it assures its structural stability and prevents any leaching of heavy metals that it contains. The authors have identified that adding 20 to 26 % of flue ash into the injection reduces the mortar hardening time by 30 %, while the strength of the mortar that has 20 % of ash is almost equal to the one of the benchmark sample. However, any higher ash content causes deterioration of the hardening strength of the mortar. Therefore, the authors have discovered that 20 % of the cement may be replaced by the ash generated in the course of combustion of waste crossties. This replacement is to be performed in the course of preparation of mortars, and it is aimed at the strengthening of the soil. This operation is to be performed in the incinerator to preserve the solution properties. This technology reduces the amount of hazardous by-products through their recycling.

  16. A multiscale mortar multipoint flux mixed finite element method

    KAUST Repository

    Wheeler, Mary Fanett

    2012-02-03

    In this paper, we develop a multiscale mortar multipoint flux mixed finite element method for second order elliptic problems. The equations in the coarse elements (or subdomains) are discretized on a fine grid scale by a multipoint flux mixed finite element method that reduces to cell-centered finite differences on irregular grids. The subdomain grids do not have to match across the interfaces. Continuity of flux between coarse elements is imposed via a mortar finite element space on a coarse grid scale. With an appropriate choice of polynomial degree of the mortar space, we derive optimal order convergence on the fine scale for both the multiscale pressure and velocity, as well as the coarse scale mortar pressure. Some superconvergence results are also derived. The algebraic system is reduced via a non-overlapping domain decomposition to a coarse scale mortar interface problem that is solved using a multiscale flux basis. Numerical experiments are presented to confirm the theory and illustrate the efficiency and flexibility of the method. © EDP Sciences, SMAI, 2012.

  17. Study of sticky rice-lime mortar technology for the restoration of historical masonry construction.

    Science.gov (United States)

    Yang, Fuwei; Zhang, Bingjian; Ma, Qinglin

    2010-06-15

    Replacing or repairing masonry mortar is usually necessary in the restoration of historical constructions, but the selection of a proper mortar is often problematic. An inappropriate choice can lead to failure of the restoration work, and perhaps even further damage. Thus, a thorough understanding of the original mortar technology and the fabrication of appropriate replacement materials are important research goals. Many kinds of materials have been used over the years in masonry mortars, and the technology has gradually evolved from the single-component mortar of ancient times to hybrid versions containing several ingredients. Beginning in 2450 BCE, lime was used as masonry mortar in Europe. In the Roman era, ground volcanic ash, brick powder, and ceramic chip were added to lime mortar, greatly improving performance. Because of its superior properties, the use of this hydraulic (that is, capable of setting underwater) mortar spread, and it was adopted throughout Europe and western Asia. Perhaps because of the absence of natural materials such as volcanic ash, hydraulic mortar technology was not developed in ancient China. However, a special inorganic-organic composite building material, sticky rice-lime mortar, was developed. This technology was extensively used in important buildings, such as tombs, in urban constructions, and even in water conservancy facilities. It may be the first widespread inorganic-organic composite mortar technology in China, or even in the world. In this Account, we discuss the origins, analysis, performance, and utility in historic preservation of sticky rice-lime mortar. Mortar samples from ancient constructions were analyzed by both chemical methods (including the iodine starch test and the acid attack experiment) and instrumental methods (including thermogravimetric differential scanning calorimetry, X-ray diffraction, Fourier transform infrared, and scanning electron microscopy). These analytical results show that the ancient masonry

  18. Evaluation of pulp and mortar to pack bitumen radioactive waste

    International Nuclear Information System (INIS)

    Gregorio, Marina da S.; Vieira, Vanessa M.; Tello, Cledola C.O.

    2013-01-01

    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

  19. PREPARATION OF MORTARS FOR RESTORATION OF ARCHITECTURAL MONUMENTS

    Directory of Open Access Journals (Sweden)

    TEREZA TRIBULOVÁ

    2012-09-01

    Full Text Available Mortar mixtures were prepared considering the microscopic observation, granulometric analysis, mercury porosimetry, XRD analysis, thermogravimetric and differential thermal analysis of the original plaster. Two series of lime mortar samples containing identical mixture of aggregates and admixtures but varying in the kind of a lime binder were prepared. In addition, the sample series varied in the ratio between mixing aggregate and binder. Prepared test bodies were subjected to accelerated carbonation process. Carbonated samples were characterized by the measurement of compressive strength, open porosity, water absorption and resistance to salt crystallization. The samples were also again compared with the original plaster by optical microscopy and XRD analysis. Based on the results of analyses of the original plasters and prepared samples of repair mortar the sample containing lime slurry with the mixture of aggregates in the mixing ratio of 1 : 2 was recommended for the restoration procedure.

  20. Reuse of ash coal in the formulation of mortars

    International Nuclear Information System (INIS)

    Siqueira, J.S.; Souza, C.A.G.; Souza, J.A.S.

    2012-01-01

    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)

  1. The dynamic behavior of mortar under impact-loading

    Science.gov (United States)

    Kawai, Nobuaki; Inoue, Kenji; Misawa, Satoshi; Tanaka, Kyoji; Hayashi, Shizuo; Kondo, Ken-Ichi; Riedel, Werner

    2007-06-01

    Concrete and mortar are the most fundamental structural material. Therefore, considerable interest in characterizing the dynamic behavior of them under impact-loading exists. In this study, plate impact experiments have been performed to determine the dynamic behavior of mortar. Longitudinal and lateral stresses have been directly measured by means of embedded polyvinylidene fluoride (PVDF) gauges up to 1 GPa. A 200 mm-cal. powder gun enable us to measure longitudinal and lateral stresses at several point from the impact surface, simultaneously. The shear strength under impact-loading has been obtained from measured longitudinal and lateral stresses. The longitudinal stress profile shows a two-wave structure. It is indicated that this structure is associated with the onset of pore compaction and failure of mortar by comparing with hydrocode simulations using an elastic-plastic damage model for concrete.

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

    International Nuclear Information System (INIS)

    Ribeiro, D.V.; Morelli, M.R.

    2011-01-01

    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)

  3. 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

  4. Damages to masonry due to interaction(s) between mortar and brick

    NARCIS (Netherlands)

    Klugt, L.J.A.R. van der

    1995-01-01

    Masonry consists of brick and mortar. Next to the laying mortar there can be a separate pointing mortar as well. Each of these components can suffer damage. Such damages, of course, have to do with the properties of the components and with the agressiveness of the environment. However, next to their

  5. 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

  6. Homogeneity and Strength of Mortar Joints in Pearl-Chain Bridges

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Arvidsson, Michael; Hansen, Kurt Kielsgaard

    2015-01-01

    -to-mix mortar products are tested. To the authors’ knowledge, no previous published work has documented the homogeneity and properties of mortar joints of such a height. Hence, the present study documents a practical test procedure where the homogeneity of three mortar joints measuring 20 x 220 x 2400 mm has...

  7. Various mortars for anti-fouling purposes in marine environments

    International Nuclear Information System (INIS)

    Kanematsu, Hideyuki; Masuda, Tomoka; Miura, Yoko; Kuroda, Daisuke; Hirai, Nobumitsu; Yokoyama, Seiji

    2014-01-01

    The antifouling properties for some mortars with steel making slags were investigated by real marine immersion tests and a unique laboratory acceleration tests with a specially devised biofilm acceleration reactors. Mortars mixed with steel making slags containing abundant iron elements tended to form biofilm and also bifouling. The two kinds of biofilm formation tests were used in this study. Real immersion in marine environments and laboratory test with a specially devised biofilm acceleration reactor. The former evaluated the biofouling characteristics more properly, while the latter did the biofilm formation characteristics more effectively

  8. 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...

  9. Various mortars for anti-fouling purposes in marine environments

    Energy Technology Data Exchange (ETDEWEB)

    Kanematsu, Hideyuki; Masuda, Tomoka [Department of Materials Science and Engineering, Suzuka National College of Technology, Shiroko-cho, Suzuka, Mie 510-0294 (Japan); Miura, Yoko; Kuroda, Daisuke [Department of General Education, The Company, Suzuka National College of Technology, Shiroko-cho, Suzuka, Mie 510-0294 (Japan); Hirai, Nobumitsu [Department of Chemistry and Biochemistry, Suzuka National College of Technology, Shiroko-cho, Suzuka, Mie 510-0294 (Japan); Yokoyama, Seiji [Department of Mechanical Engineering, Toyohashi University of Technology, 1-1, Hibarigaoka, Tenpaku, Toyohashi, Aichi, 441-8580 (Japan)

    2014-02-20

    The antifouling properties for some mortars with steel making slags were investigated by real marine immersion tests and a unique laboratory acceleration tests with a specially devised biofilm acceleration reactors. Mortars mixed with steel making slags containing abundant iron elements tended to form biofilm and also bifouling. The two kinds of biofilm formation tests were used in this study. Real immersion in marine environments and laboratory test with a specially devised biofilm acceleration reactor. The former evaluated the biofouling characteristics more properly, while the latter did the biofilm formation characteristics more effectively.

  10. Ancient mortars from Cape Verde: mineralogical and physical characterization

    Science.gov (United States)

    Rocha, Fernando; Costa, Cristiana; Velosa, Ana; Quintela, Ana; Terroso, Denise; Marques, Vera

    2014-05-01

    Times and locations of different building constructions means different knowledge, habits, different construction methods and materials. The study and safeguarding of the architectural heritage takes nowadays a progressive importance as a vehicle for transmission of cultures and history of nations. The coatings are of great importance in the durability of a building due to the protective role of the masonry. The compatibility between the materials with which they are executed (masonry, mortar and grout settlement) promotes the proper functioning of the wall and a consequent increase in durability. Therefore, it becomes important to study and characterize the mortar coating of buildings to know its characteristics and to use compatible materials in the rehabilitation and maintenance of buildings. This study aims to characterize the chemical, physical, mechanical and mineralogical mortar samples collected in buildings in three islands of Cape Verde, for the conservation, rehabilitation and preservation of them. The collected samples belong to buildings constructed in the end of XIX century and in the beginning of XX century. In order to characterize the mortar samples some tests was made, such as X-Ray Diffraction, X- Ray Fluorescence, acid attack and mechanical strength. The samples were divided into three groups depending on origin; so we have a first group collected on the island of Santiago, the second on the island of Saint Vincent and the third on the island of Santo Antao. The samples are all carbonated, but Santiago samples have a lower carbonates content. In terms of insoluble residue (from the acid attack) it was concluded that the samples have similar value ranging from 9 to 26%. The compressive strength of the mortars have a range between 1.36 and 4.55 MPa, which is related to the presence of more binder in samples with higher resistance. The chemical and mineralogical analyzes showed that these consist of lime mortars (binder), natural pozzolan and

  11. Study on basalt fiber parameters affecting fiber-reinforced mortar

    Science.gov (United States)

    Orlov, A. A.; Chernykh, T. N.; Sashina, A. V.; Bogusevich, D. V.

    2015-01-01

    This article considers the effect of different dosages and diameters of basalt fibers on tensile strength increase during bending of fiberboard-reinforced mortar samples. The optimal dosages of fiber, providing maximum strength in bending are revealed. The durability of basalt fiber in an environment of cement, by means of microscopic analysis of samples of fibers and fiberboard-reinforced mortar long-term tests is examined. The article also compares the behavior of basalt fiber in the cement stone environment to a glass one and reveals that the basalt fiber is not subject to destruction.

  12. Light brick mortar with low thermal conductivity for stressed brickwork. Types, properties, limits of application

    Energy Technology Data Exchange (ETDEWEB)

    Plank, A [Bundesanstalt fuer Materialpruefung, Berlin (Germany, F.R.)

    1980-03-01

    Between 40 and 50% of the total energy consumption are used for space heating. 40% of the total heat loss dissipate through external walls due to transmission. The heat insulation properties of a brickwork is decisively determined by the mortar joints. Using light brick mortars with low thermal conductivity an improvement of the total thermal insulation of nearly 20% can be reached in most of the cases. The mechanical properties of these mortars that differ from the common mortars decisively reduce the application of the light brick mortar in brick working and require special measures for stability which are described in detail.

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

    OpenAIRE

    Zhao, Xiao; Lim, Siong-Kang; Tan, Cher-Siang; Li, Bo; Ling, Tung-Chai; Huang, Runqiu; Wang, Qingyuan

    2015-01-01

    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). ...

  14. Simulation of the self-healing of dolomitic lime mortar

    NARCIS (Netherlands)

    Lubelli, B.; Nijland, T.G.; Hees, R.P.J. van

    2012-01-01

    A test procedure was set up to reproduce laboratory self-healing on lime-based (both pure calcium and magnesium-calcium) mortar specimens. After a few months of testing, during which time the specimens were submitted to wet-dry cycles, thin sections of the specimens were prepared and observed using

  15. Simulation of self-healing of dolomitic lime mortar

    NARCIS (Netherlands)

    Lubelli, B.; Nijland, T.G.; Van Hees, R.P.J.

    2011-01-01

    In the present research a test procedure was set up to reproduce self-healing on lime-based (both pure calcium and magnesium-calcium) mortar specimens in laboratory. After few months testing, during which the specimens were subjected to wet-dry cycles, thin sections of the specimens were prepared

  16. Determination of the chloride diffusion coefficient in blended cement mortars

    NARCIS (Netherlands)

    Elfmarkova, V.; Spiesz, P.R.; Brouwers, H.J.H.; Bilek, V.; Kersner, Z.

    2014-01-01

    Literature shows that the RCM test development and experience concerns only Ordinary Portland cement. Therefore, a validation of this test method is needed for other types of binders. This study analyzes the application of RCM test for mortars prepared with different binders: Ordinary Portland

  17. A nano approach to consolidation of degraded historic lime mortars

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš; Slížková, Zuzana; Ziegenbalg, G.

    2009-01-01

    Roč. 8, č. 2 (2009), s. 13-22 ISSN 1662-5250 R&D Projects: GA ČR(CZ) GA103/06/1609 Institutional research plan: CEZ:AV0Z20710524 Keywords : lime water * calcium hydroxide nanosuspension * lime mortar Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 0.571, year: 2009

  18. Lime-water consolidation effects on poor lime mortars

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš; Slížková, Zuzana

    2012-01-01

    Roč. 43, č. 1 (2012), s. 31-36 ISSN 0044-9466 R&D Projects: GA ČR(CZ) GA103/09/2067 Institutional support: RVO:68378297 Keywords : lime mortar s * lime -water consolidation * conservation Subject RIV: JN - Civil Engineering

  19. Chloride penetration into cementitious mortar at early age

    NARCIS (Netherlands)

    Caballero, J.; Polder, R.B.; Leegwater, G.A.; Fraaij, A.L.A.

    2012-01-01

    Modern service life design methods for concrete structures use chloride diffusion data as an input parameter. Abundant data exist for concrete at 28 days and, to a lesser extent, at later ages. This paper presents chloride diffusion data for mortar at ages between 1 day and 28 days age. Rapid

  20. Low Carbon Footprint mortar from Pozzolanic Waste Material

    Science.gov (United States)

    Mehmannavaz, Taha; Mehman navaz, Hossein Ali; Moayed Zefreh, Fereshteh; Aboata, Zahra

    2017-04-01

    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 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.

  1. Do Schools Still Need Brick-and-Mortar Libraries?

    Science.gov (United States)

    Johnson, Doug; Mastrion, Keith

    2009-01-01

    Do all schools need brick-and-mortar libraries? In this article, Johnson and Mastrion share their contradictory thoughts to the question. Johnson says some schools don't need library facilities or programs or librarians. These schools' teachers and administrators: (1) feel no need for a collaborative learning space; (2) feel the ability to process…

  2. Finite element stress analysis of brick-mortar masonry under ...

    African Journals Online (AJOL)

    Stress analysis of a brick-mortar couplet as a substitute for brick wall structure has been performed by finite element method, and algorithm for determining the element stiffness matrix for a plane stress problem using the displacement approach was developed. The nodal displacements were derived for the stress in each ...

  3. Mortar and concrete based on calcium sulphate binders

    NARCIS (Netherlands)

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

    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

  4. Study of the laboratory Vane test on mortars

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Elton [Post-Graduate Program in Structures and Civil Construction, Civil and Environmental Engineering Department, University of Brasilia Campus Universitario Darcy Ribeiro Asa Norte, 70910-900 Brasilia/DF (Brazil); Sousa, Jose G.G. de [Federal University of Vale do Sao Francisco, Av. Presidente Tancredo Neve, 100-56306-410 Petroline/PE (Brazil); Guimaraes, Elvio A. [University of Feira de Santana, Campus Universitario-BR 116, Km 03-44031-460-Feira de Santana/BA (Brazil); Silva, Francisco Gabriel S. [Post-Graduate Program in Structures and Civil Construction, University of Brasilia Campus Universitario Darcy Ribeiro Asa Norte, 70910-900 Brasilia/DF (Brazil)

    2007-01-15

    The Vane method (Vane test) is a simple but efficient method to measure the yield stress among other properties of non-Newtonian fluids. These fluids exhibit big flow effects in flat surfaces which are common in rheometers devices of different types (parallel disk or coaxial cylinder types). The yield stress values obtained with Vane method, in pastes, gels, soils and concentrated suspensions, have presented good agreement with results found elsewhere by most of the rheologic methods shown in the literature. The aim of this work is presenting a discussion on the capabilities of the Vane method, highlighting the theoretical basis, the functioning principle with some operational particularities, and some applications of the method in investigating the properties of fresh rendering mortars. Works of several authors that used the same method for fresh mortars were reviewed and experimental results of tests done by the authors of this paper using the method are also presented and discussed, focusing on the desirable workability for mortars. The Vane test method is an important tool in studying rheological properties in freshly applied mortar. It is able to define clear conditions in the applying of this material. (author)

  5. A Preliminary Study on Cathodic Prevention in Reinforced Mortar

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.; Mol, J.M.C.; De Wit, J.H.W.

    2010-01-01

    This work presents the preliminary tests on the performance of cathodic prevention (CPre) in reinforced mortar, subjected to aggressive (10% NaCl environment). Cathodic prevention is an electrochemical technique for minimizing, actually "preventing" any eventual corrosion of the steel bars in

  6. Investigation of Induction Heating in Asphalt Mortar: Numerical Approach

    NARCIS (Netherlands)

    Apostolidis, P.; Liu, X.; Scarpas, Athanasios; van de Ven, M.F.C.; van Bochove, G

    2016-01-01

    The research reported in this paper focuses on utilization of advanced finite-element analyses (COMSOL) for the design and assessment of the induction heating capacity of asphalt mortar by adding electrically conductive additives (e.g., steel fibers), and to understand the factors that influence the

  7. Dispersibility of silica fume in mortar and its effect on properties of mortar. Silica fume no bunsan to mortar no shotokusei

    Energy Technology Data Exchange (ETDEWEB)

    Oga, H; Uomoto, T [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

    1992-08-01

    Effect of silica fume dispersibility on concrete characteristics was discussed. Properties of mortar mixed with silica fume to exhibit compression strength varied with displacement rates, patterns, and mixing time of silica fume. In submerged curing age of 28 days, the compression strength in a mortar mixed with silica fume at 10% was affected only very little by the mixing time for both pelletizing and non-pelletizing types for up to 180 seconds. The strength increased thereafter with the mixing time. The compression strength at 1020 seconds showed higher value by about 150 kgf/cm [sup 2] than when no silica fume is added, with a difference because of patterns disappearing. In the case of a mixing time of 1020 seconds, neutralization depth receives very little effect from a pattern difference, and decreases with increasing displacement rate. Neutralization coefficient of the mortar mixed with silica fume at 10% decreased with the mixing time, and it was possible to suppress the neutralization coefficient to 25% of the case without silica fume addition in a 1020-second mixing. 7 refs., 8 figs., 1 tab.

  8. 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.

  9. The potential use of silica sand as nanomaterials for mortar

    Science.gov (United States)

    Setiati, N. Retno

    2017-11-01

    The development of nanotechnology is currently experiencing rapid growth. The use of the term nanotechnology is widely applied in areas such as healthcare, industrial, pharmaceutical, informatics, or construction. By the nanotechnology in the field of concrete construction, especially the mechanical properties of concrete are expected to be better than conventional concrete. This study aims to determine the effect of the potential of silica sand as a nanomaterial that is added into the concrete mix The methodology used consist of nanomaterial synthesis process of silica sand using Liquid Polishing Milling Technology (PLMT). The XRF and XRD testing were conducted to determine the composition of silica contained in the silica sand and the level of reactivity of the compound when added into the concrete mix. To determine the effect of nano silica on mortar, then made the specimen with size 50 mm x 50 mm x 50 mm. The composition of mortar is made in two variations, ie by the addition of 3% nano silica and without the addition of nanosilica. To know the mechanical properties of mortar, it is done testing of mortar compressive strength at the age of 28 days. Based on the analysis and evaluation, it is shown that compounds of silica sand in Indonesia, especially Papua reached more than 99% SiO2 and so that the amorphous character of silica sand can be used as a nanomaterial for concrete construction. The results of mechanical tests show that there is an increase of 12% compressive strength of mortar that is added with 3% nano silica.

  10. 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.

  11. Strengthening Masonry Arches with Lime-Based Mortar Composite

    Directory of Open Access Journals (Sweden)

    Valerio Alecci

    2017-06-01

    Full Text Available In recent decades, many strengthening interventions on masonry elements were performed by using fiber reinforced polymers (FRPs. These advanced materials proved to be effective to increase the load-carrying capacity of masonry elements and to improve their structural behavior, avoiding the most critical failure modes. Despite the advantages of this technique compared to more traditional methods, FRP systems have disadvantages related to their low resistance to high temperatures, impossibility of application on wet surfaces, low permeability, and poor compatibility with masonry supports. Therefore, composite materials made of a fiber textile embedded in an inorganic matrix were recently proposed as alternatives to FRPs for strengthening historic masonry constructions. These composite materials are easier to install, have higher resistance to high temperatures, and permit higher vapor permeability than FRPs. The inorganic matrix is frequently a cement-based mortar, and the composite materials made of a fiber textile embedded in a cement-based mortar are usually identified as FRCM (fabric reinforced cementitious matrix composites. More recently, the use of natural lime mortar as an inorganic matrix has been proposed as an alternative to cement-based mortars when historic compatibility with the substrate is strictly required, as in case of restoration of historic buildings. In this paper, the effectiveness of a fabric made of basalt fibers embedded in lime mortar matrix (Basalt-FRLM for the strengthening of masonry arches is investigated. An experimental investigation was performed on 1:2 scaled brick masonry arches strengthened at the extrados with a layer of Basalt-FRLM and tested under vertical load. The results obtained are compared with previous results obtained by the authors by testing masonry arches strengthened at their extrados with FRCM and FRP composites. This investigation highlights the effectiveness of Basalt-FRLM in increasing load

  12. Adhesion in microelectronics

    CERN Document Server

    Mittal, K L

    2014-01-01

    This comprehensive book will provide both fundamental and applied aspects of adhesion pertaining to microelectronics in a single and easily accessible source. Among the topics to be covered include; Various theories or mechanisms of adhesionSurface (physical or chemical) characterization of materials as it pertains to adhesionSurface cleaning as it pertains to adhesionWays to improve adhesionUnraveling of interfacial interactions using an array of pertinent techniquesCharacterization of interfaces / interphasesPolymer-polymer adhesionMetal-polymer adhesion  (metallized polymers)Polymer adhesi

  13. Long-term dentin retention of etch-and-rinse and self-etch adhesives and a resin-modified glass ionomer cement in non-carious cervical lesions

    DEFF Research Database (Denmark)

    Dijken, J.W.V. van; Pallesen, U.

    2008-01-01

    The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems.......The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems....

  14. Reflections about Adhesive Systems

    OpenAIRE

    de Freitas Borges, Marciano; Diesel, Pâmela Gutheil; Corrêa, Fernanda Gomez; Bernardi, Eledana; Fernandes Montagner, Anelise; Skupien, Jovito Adiel; Susin, Alexandre Henrique

    2010-01-01

    The adhesive systems are responsible for an efficient union between teeth and resin, resulting in a longevity restoration. They are organic molecules di or multifunctional that contain reactive groups that interact with dentin and with the resin monomer of composite resin. The adhesive systems are characterized by wet adhesion, which is a result of presence of hidrophylics radicals in their compositions, to promote a better bond and the best properties of the adhesion. Adhesive systems may us...

  15. Sulfate resistance of nanosilica contained Portland cement mortars

    Science.gov (United States)

    Batilov, Iani B.

    Soils, sea water and ground water high in sulfates are commonly encountered hostile environments that can attack the structure of concrete via chemical and physical mechanisms which can lead to costly repairs or replacement. Sulfate attack is a slow acting deteriorative phenomenon that can result in cracking, spalling, expansion, increased permeability, paste-to-aggregate bond loss, paste softening, strength loss, and ultimately, progressive failure of concrete. In the presented research study, Portland cement (PC) mortars containing 1.5% to 6.0% nanosilica (nS) cement replacement by weight were tested for sulfate resistance through full submersion in sodium sulfate to simulate external sulfate attack. Mortars with comparable levels of cement replacement were also prepared with microsilica (mS). Three cement types were chosen to explore nS' effectiveness to reduce sulfate expansion, when paired with cements of varying tricalcium aluminate (C3A) content and Blaine fineness, and compare it to that of mS. Mortars were also made with combined cement replacement of equal parts nS and mS to identify if they were mutually compatible and beneficial towards sulfate resistance. Besides sulfate attack expansion of mortar bars, the testing program included investigations into transport and microstructure properties via water absorption, sulfate ion permeability, porosimetry, SEM with EDS, laser diffraction, compressive strength, and heat of hydration. Expansion measurements indicated that mS replacement mortars outperformed both powder form nS, and nS/mS combined replacement mixtures. A negative effect of the dry nS powder replacement attributed to agglomeration of its nanoparticles during mixing negated the expected superior filler, paste densification, and pozzolanic activity of the nanomaterial. Agglomerated nS was identified as the root cause behind poor performance of nS in comparison to mS for all cement types, and the control when paired with a low C3A sulfate resistant

  16. 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.

  17. 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

  18. 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

  19. Study on properties of mortar using silica fume and ground blast furnace slag. Silica fume oyobi koro slag funmatsu wo mochiita mortar no tokusei ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Shiiba, H; Honda, S; Araki, A [Fukuoka University, Fukuoka (Japan). Faculty of Engineering

    1992-09-01

    The effect of silica fume and ground blast furnace slag in concrete on the content of superplasticizer, and dynamic properties of hardened mortar with such admixtures were studied experimentally. Although the dependence of a flow value on the superplasticizer was dominated by kinds of superplasticizers, blast furnace slag enhanced the flow value resulting in a high fluidity. Adsorption of superplasticizers onto admixtures was dependent on kinds of superplasticizers, and adsorption onto blast furnace slag was 1.3-2 times that onto normal Portland cement (NPC). The compressive strength of mortar increased by mixing admixtures, while the bending strength was enhanced only by mixing silica fume. Mixing mortar was lower in dynamic elastic modulus than NPC mortar at the same compressive strength, and the velocity of supersonic wave in mortar was scarcely affected by mixing. 11 refs., 14 figs., 3 tabs.

  20. Influence of the segregation of the granulate from the radwaste-mortar mixture from on the {sup 137}Cs leach-rate; Uticaj segregacije granulata iz sastava betonske - RAO forme na izluzivanje Cs{sup 137}

    Energy Technology Data Exchange (ETDEWEB)

    Peric, A; Plecas, I; Pavlovic, R; Pavlovic, S [Institute of Nuclear Sciences VINCA, Belgrade (Yugoslavia)

    1994-07-01

    In this paper. influence of the segregation of the granulate, presented in the radwaste-mortar matrix formulation, on the {sup 137}Cs, immobilized in the waste form, leach-rate is presented. {sup 137}Cs leach-rates of the two inspected groups of the radwaste-mortar mixture samples were compared, where the first group of the orthocylinder shaped samples was treated due to the Standard Hespe's method and the second group was treated using modified Hespe's method. In the prolonged experimental time, both groups have obtained leach-rate values that are nearly the same, striving to the saturation leach-rate values. This fact indicates that the leaching of the radionuclide as a consequence of the granulate segregation process is in same way rebuilt, as a result of the completed hydratation of the mortar matrix, and 'self healing' of the new open pores and cavities (author)

  1. Compressive strength of concrete and mortar containing fly ash

    Science.gov (United States)

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

    1997-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specifications required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs.

  2. Durability of Mortar Made with Fine Glass Powdered Particles

    Directory of Open Access Journals (Sweden)

    Rosemary Bom Conselho Sales

    2017-01-01

    Full Text Available Different studies investigate the use of waste glass in Portland cement compounds, either as aggregates or as supplementary cementitious materials. Nevertheless, it seems that there is no consensus about the influence of particle color and size on the behavior of the compounds. This study addresses the influence of cement replacement by 10 and 20% of the colorless and amber soda-lime glass particles sized around 9.5 μm on the performance of Portland cement mortars. Results revealed that the partial replacement of cement could contribute to the production of durable mortars in relation to the inhibition of the alkali-aggregate reaction. This effect was more marked with 20% replacement using amber glass. Samples containing glass microparticles were more resistant to corrosion, in particular those made of colorless glass. The use of colorless and amber glass microparticles promoted a reduction in wear resistance.

  3. Finite cover method with mortar elements for elastoplasticity problems

    Science.gov (United States)

    Kurumatani, M.; Terada, K.

    2005-06-01

    Finite cover method (FCM) is extended to elastoplasticity problems. The FCM, which was originally developed under the name of manifold method, has recently been recognized as one of the generalized versions of finite element methods (FEM). Since the mesh for the FCM can be regular and squared regardless of the geometry of structures to be analyzed, structural analysts are released from a burdensome task of generating meshes conforming to physical boundaries. Numerical experiments are carried out to assess the performance of the FCM with such discretization in elastoplasticity problems. Particularly to achieve this accurately, the so-called mortar elements are introduced to impose displacement boundary conditions on the essential boundaries, and displacement compatibility conditions on material interfaces of two-phase materials or on joint surfaces between mutually incompatible meshes. The validity of the mortar approximation is also demonstrated in the elastic-plastic FCM.

  4. Fracture mechanics of polymer mortar made with recycled raw materials

    Directory of Open Access Journals (Sweden)

    Marco Antonio Godoy Jurumenha

    2010-12-01

    Full Text Available The aim of this work is to show that industrial residues could be used in construction applications so that production costs as well as environmental protection can be improved. The fracture properties of polymer mortar manufactured with recycled materials are investigated to evaluate the materials behaviour to crack propagation. The residues used in this work were spent sand from foundry industry as aggregate, unsaturated polyester resin from polyethylene terephthalate (PET as matrix and polyester textile fibres from garment industry, producing an unique composite material fully from recycled components with low cost. The substitution of fresh by used foundry sand and the insertions of textile fibres contribute to a less brittle behaviour of polymer mortar.

  5. Radiation chemical treatment of cement mortar - polymer composites

    International Nuclear Information System (INIS)

    Younes, M.M.

    1994-01-01

    The development of the hardened cement pastes,mortars and concretes which contain polymers has progressed rapidly in years. Developmental work has identified a number of applications where the high strength and excellent durability of the composite materials will provide definite advantages over conventional mortars and concretes. The first investigations of polymer - impregnated concrete tried mainly to increase the quantity of absorbed and polymerised monomer because this gave a greater decrease in the original of concrete and a subsequent improvement in physico - mechanical properties. However, the production costs which is due mainly to the organic polymer, becomes the most important item. In this respect recent research showed the possibility of obtaining with a very compact concrete, of relative low porosity, a compound material with high performances after impregnation 26 tabs.,28 figs.,109 refs

  6. Effect of temperature on the mechanical properties of polymer mortars

    Directory of Open Access Journals (Sweden)

    João Marciano Laredo dos Reis

    2012-08-01

    Full Text Available This paper presents the results of an experimental program to investigate the effect of temperature on the performance of epoxy and unsaturated polyester polymer mortars (PM. PM is a composite material in which polymeric materials are used to bond the aggregates in a fashion similar to that used in the preparation of Portland cement concrete. For this purpose, prismatic and cylindrical specimens were prepared for flexural and compressive tests, respectively, at different temperatures. Measurements of the temperature-dependent elastic modulus and the compressive and flexural strength were conducted using a thermostatic chamber attached to a universal test machine for a range of temperatures varying from room temperature to 90 ºC. The flexural and compressive strength decreases as temperature increases, especially after matrix HDT. Epoxy polymer mortars are more sensitive to temperature variation than unsaturated polyester ones.

  7. Valorization of mud from Fergoug dam in manufacturing mortars

    Directory of Open Access Journals (Sweden)

    L. Laoufi

    2016-12-01

    Full Text Available The production of calcined mud, with pozzolanic properties, from the large quantities of sediments dredged from Algerian dams, could be a good opportunity for the formulation of high performance mortars and pozzolanic concretes, with lower costs and less greenhouse gas (CO2 emissions. The optimal temperatures selected for calcination were 750, 850 and 950 °C. The burning operation was continuous over a period of 3 h. Therefore, a series of physical, chemical, mechanical and microstructural analyses were conducted on sediment samples, collected from the waters of Fergoug dam. The results obtained from the analyses of the calcined mud, from the dam, allowed saying that mortars with different percentages of that mud represent a potential source of high reactivity pozzolanic materials.

  8. Characterization of civil construction waste and its incorporation to mortar

    International Nuclear Information System (INIS)

    Cunha, G.A.; Andrade, A.C.D.; Souza, J.M.M.; Evangelista, A.C.J.; Almeida, V.C.

    2009-01-01

    As the preservation of the environment is a big concern nowadays, plenty of studies have arisen in order to decrease the production or reuse the waste from human activities. In this context, the civil construction industry comes up, as it is able to incorporate waste to mortar, being a great alternative for the reuse of solid waste. The scope of this work has been the characterization of Construction and Demolishment Waste (RCD) and its incorporation to the mortar aiming at the development of alternative construction materials in the future for the economical reutilization of waste discharged in embankments and landfills so far preserving the environment so far. The experimental studies taken with sample bodies, such as water absorption, resistance to compression, X-ray diffraction, X-ray fluorescence and scanning electronic microscopy, elicits the viability of the partial substitution of cement by RCD mixed waste, taking its different applications into consideration. (author)

  9. 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 z......-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....... 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...

  10. 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.

  11. A lime based mortar for thermal insulation of medieval church vaults

    DEFF Research Database (Denmark)

    Larsen, P.K.; Hansen, Tessa Kvist

    A new mortar for thermal insulation of medieval church vaults was tested in a full scale experiment in Annisse Church, DK. The mortar consists of perlite, a highly porous aggregate, mixed with slaked lime. These materials are compatible with the fired clay bricks and the lime mortar joints....... The lambda-value of the insulation mortar is 0.08 W/m K or twice the lambda-value for mineral wool. The water vapour permeability is equal to a medieval clay brick, and it has three times higher capacity for liquid water absorption. The mortar was applied to the top side of the vaults in a thickness of 10 cm......, despite a water vapour pressure gradient up to 500 Pa between the nave and attic. There was no reduction in energy consumption the first winter, possibly due to the increased heat loss related to the drying of the mortar....

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

    International Nuclear Information System (INIS)

    Wyrzykowski, Mateusz; Trtik, Pavel; Münch, Beat; Weiss, Jason; Vontobel, Peter; Lura, Pietro

    2015-01-01

    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

  13. Freezing and thawing resistance of aerial lime mortar with metakaolin\

    Czech Academy of Sciences Publication Activity Database

    Nunes, Cristiana Lara; Slížková, Zuzana

    2016-01-01

    Roč. 114, July (2016), s. 896-905 ISSN 0950-0618 R&D Projects: GA ČR(CZ) GBP105/12/G059 Institutional support: RVO:68378297 Keywords : freeze-thaw * lime * metakaolin * linseed oil * mortar * water-repellency Subject RIV: JN - Civil Engineering Impact factor: 3.169, year: 2016 http://www.sciencedirect.com/science/article/pii/S0950061816305645

  14. Fracture mechanics of polymer mortar made with recycled raw materials

    OpenAIRE

    Jurumenha,Marco Antonio Godoy; Reis,João Marciano Laredo dos

    2010-01-01

    The aim of this work is to show that industrial residues could be used in construction applications so that production costs as well as environmental protection can be improved. The fracture properties of polymer mortar manufactured with recycled materials are investigated to evaluate the materials behaviour to crack propagation. The residues used in this work were spent sand from foundry industry as aggregate, unsaturated polyester resin from polyethylene terephthalate (PET) as matrix and po...

  15. Compressive and flexural strength of high strength phase change mortar

    Science.gov (United States)

    Qiao, Qingyao; Fang, Changle

    2018-04-01

    High-strength cement produces a lot of hydration heat when hydrated, it will usually lead to thermal cracks. Phase change materials (PCM) are very potential thermal storage materials. Utilize PCM can help reduce the hydration heat. Research shows that apply suitable amount of PCM has a significant effect on improving the compressive strength of cement mortar, and can also improve the flexural strength to some extent.

  16. Properties of Fiber-Reinforced Mortars Incorporating Nano-Silica

    OpenAIRE

    Ahmed Ghazy; Mohamed T. Bassuoni; Eugene Maguire; Mark O’Loan

    2016-01-01

    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 m...

  17. Optimization of superplasticizer in portland pozzolana cement mortar and concrete

    Science.gov (United States)

    Sathyan, Dhanya; Anand, K. B.; Mini, K. M.; Aparna, S.

    2018-02-01

    Chemical Admixtures are added to concrete at the time of mixing of its constituents to impart workability. The requirement of right workability is the essence of good concrete. It has been found that the use of optimum use of admixtures is very important since low dosage may result in loss of fluidity and over dosage could lead to segregation, bleeding, excessive air entrainment etc in concrete. Hence it is essential to find optimum dosage of superplasticizer for getting good strength and workability. But large number of trial tests are required in the field to find the saturation dosage of superplasticizer in concrete which requires more materials and consume more time. The paper deals with developing a co-relation between the quantity requirements of superplasticiser in mortar to that of cement concrete to get good workability. In this work for preparing mortar and concrete 4 brands of locally available Portland pozzolana cement (PPC) and superplasticizer (SP) belonging to 4 different families namely Polycarboxylate Ether (PCE), Lignosulphate (LS), Sulfonated Naphthalene Formaldehyde (SNF) and Sulfonated Melamine Formaldehyde (SMF) are used. Two different brands of SP’s are taken from each family. Workability study on the superplasticized mortar with cement to sand ratio 1:1.5 and water cement ratio of 0.4 was performed using marsh cone and flow table test and workability study on the concrete with same cement/sand ratio and water cement ratio was done using slump cone and flow table test. Saturation dosage of superplasticizer in mortar and concrete determined experimentally was compared to study the correlation between two. Compressive strength study on concrete cubes were done on concrete mixes with a superplasticizer dosage corresponding to the saturation dosage and a comparative study were done to analyse the improvement in the compressive strength with addition of superplasticizer from different family.

  18. Chapter 9:Wood Adhesion and Adhesives

    Science.gov (United States)

    Charles R. Frihart

    2013-01-01

    The recorded history of bonding wood dates back at least 3000 years to the Egyptians (Skeist and Miron 1990, River 1994a), and adhesive bonding goes back to early mankind (Keimel 2003). Although wood and paper bonding are the largest applications for adhesives, some of the fundamental aspects leading to good bonds are not fully understood. Better understanding of these...

  19. Strength Performance of Blended Ash Based Geopolymer Mortar

    Science.gov (United States)

    Zahib, Zaidahtulakmal M.; Kamaruddin, Kartini; Saman, Hamidah M.

    2018-03-01

    Geopolymer is a based on inorganic alumino-silicate binder system. Geopolymeric materials are formed using materials that containing silica and aluminium such as fly ash and rice husk ash, which activated by alkaline solution. This paper presents the study on the effect of replacement of SSA in RHA based geopolymer, types of curing and different molarity of NaOH used on the strength of Sewage Sludge Ash (SSA) and Rice Husk Ash (RHA) based geopolymer mortar incorporating with three (3) different mix proportions. Based geopolymer mortar was synthesized from treated sewage sludge and rice husk undergoing incineration process in producing ashes, activated with sodium silicate and sodium hydroxide solution by ratio of 2.5:1 and solution to ash ratio of 1:1. Molarity of 8M and 10M NaOH were used. The percentages of SSA replacement were 0%, 10% and 20% by weight. Compressive strength was conducted at age 7, 14 and 28 days to see the development of strength with two curing regimes, which are air curing and oven curing (60°C for 24 hours). From the research conducted, the ultimate compressive strength (6.28MPa) was obtained at zero replacement of SSA taken at 28 days of oven curing with 10M of NaOH. This shows that RHA, which is rich in silica content is enough to enhance the strength of geopolymer mortar especially with high molarity of NaOH.

  20. Techniques for measuring ammonia in fly ash, mortar, and concrete

    Energy Technology Data Exchange (ETDEWEB)

    Rathbone, R.F. [Kentucky Univ., Lexington, KY (United States). Center for Applied Energy Reseach; Majors, R.K. [Boral Material Technologies, Inc., San Antonio, TX (United States). Engineered Materials

    2003-12-01

    The presence of ammonia in fly ash that is to be used in mortar and concrete is of increasing concern in the U.S., mainly due to the installation of selective catalytic reduction (SCR) DeNOx systems. When the SCR catalyst is new, contamination of the fly ash with ammonia is generally not a concern. However, as the catalyst in the SCR ages and becomes less efficient, the ammonia slip increases and results in a greater amount of ammonium salt being precipitated on the fly ash. The increase in ammonia concentration is compounded by variability that can occur on a day-to-day basis. When marketing ammonia-laden fly ash for use in mortar and concrete it is imperative that the concentration of ammonia is known. However, there currently is no widely accepted or ''standard'' method for ammonia measurement in fly ash. This paper describes two methods that have been developed and used by the University of Kentucky Center for Applied Energy Research and Boral Material Technologies, Inc. One of the methods uses gas detection tubes and can provide an accurate determination within five to ten minutes. Thus it is suitable as a rapid field technique. The other method employs a gas-sensing electrode and requires a longer period of time to complete the measurement. However, this second method can also be used to determine the quantity of ammonia in fresh mortar and concrete. (orig.)

  1. Fatigue behaviour analysis for the durability prequalification of strengthening mortars

    International Nuclear Information System (INIS)

    Bocca, P; Grazzini, A; Masera, D

    2011-01-01

    An innovative laboratory procedure used as a preliminary design stage for the pre-qualification of strengthening mortars applied to historical masonry buildings is described. In the analysis of the behaviour of masonry structures and their constituent materials, increasing importance has been assumed by the study of the long-term evolution of deformation and mechanical characteristics, which may be affected by both loading and environmental conditions. Through static and fatigue tests on mixed specimens historical brick-reinforced mortar it has been possible to investigate the durability of strengthening materials, in order to select, from a range of alternatives, the most suitable for the historical masonry. Cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of the historical brick-strengthening mortar system under static long-time loading. This methodology has proved useful in avoiding the errors associated with materials that are not mechanically compatible and guarantees the durability of strengthening work. The experimental procedure has been used effectively in the biggest restoration building site in Europe, the Royal Palace of Venaria, and it is in progress of carrying out at the Special Natural Reserve of the Sacro Monte di Varallo, in Piedmont (Italy).

  2. SELECTED PROPERTIES OF EPOXY MORTARS WITH PERLITE AGGREGATE

    Directory of Open Access Journals (Sweden)

    Bernardeta Dębska

    2017-01-01

    Full Text Available Contemporarily designed, new polymer concrete-like composites are increasingly often used in construction, particularly where high chemical resistance of the material is important. However, their widespread use is limited, mainly due to the cost of resin binders used. This is a significant problem, especially in a situation where it is necessary to obtain elements of a substantial volume. One solution to this inconvenience is to develop lighter concrete. The article presents a lightweight resin mortar obtained by substitution of sand with expanded perlite. Thanks to its properties, this aggregate allows for the production of a material with a more porous structure, which is highlighted by the received SEM photos. The binder in the mortars was epoxy resin, hardened with triethylenetetramine. The results of the tests carried out allow us to conclude that despite the significant reduction of strength parameters of mortar, we can obtain a material with lower weight, good chemical resistance and low water absorption, and characterized by significant thermal insulation. This type of composites can be used, among others, as cores in sandwich panels.

  3. The Interfacial Transition Zone in Alkali-Activated Slag Mortars

    Directory of Open Access Journals (Sweden)

    Rackel eSan Nicolas

    2015-12-01

    Full Text Available The interfacial transition zone (ITZ is known to strongly influence the mechanical and transport properties of mortars and concretes. This paper studies the ITZ between siliceous (quartz aggregates and alkali activated slag binders in the context of mortar specimens. Backscattered electron images (BSE generated in an environmental scanning electron microscope (ESEM are used to identify unreacted binder components, reaction products and porosity in the zone surrounding aggregate particles, by composition and density contrast. X-ray mapping is used to exclude the regions corresponding to the aggregates from the BSE image of the ITZ, thus enabling analysis of only the binder phases, which are segmented into binary images by grey level discrimination. A distinct yet dense ITZ region is present in the alkali-activated slag mortars, containing a reduced content of unreacted slag particles compared to the bulk binder. The elemental analysis of this region shows that it contains a (C,N-A-S-H gel which seems to have a higher content of Na (potentially deposited through desiccation of the pore solution and a lower content of Ca than the bulk inner and outer products forming in the main binding region. These differences are potentially important in terms of long-term concrete performance, as the absence of a highly porous interfacial transition zone region is expected to provide a positive influence on the mechanical and transport properties of alkali-activated slag concretes.

  4. Physico Mechanical Properties of Irradiated Waste Rubber Cement Mortar

    International Nuclear Information System (INIS)

    Younes, M.M.

    2010-01-01

    In the present study a partial replacement of aggregate with two different ratios of waste rubber (5%, 10%) with the addition of a constant ratio of rice husk ash (RHA), 5% was carried out. The hardened cement mortar used the optimum water of consistency. The specimens were molded into 1 inch cubic moulds .The specimens were first cured for 24 hours, at 100% relative humidity and then cured under tap water for 3, 7 and 28 days followed by irradiation at different doses of gamma irradiation namely 5 and 10 kGy. The physico-chemical and mechanical properties such as compressive strength, total porosity and bulk density were studied for the three types of specimens. The results showed that the values of the compressive strength, bulk density and chemically combined water of the blended cement mortar paste (OPC-RHA) increase ,while blended cement mortar paste with 5% RHA and 5, 10% waste rubber decrease. The results were confirmed by scanning electron microscopy and thermal behavior of the specimens. Also, it was observed that the irradiated sample was thermally more stable than the unirradiated one

  5. Acidic Attack Resistance of Cement Mortar Treated with Alkaline

    Directory of Open Access Journals (Sweden)

    Nadia Nazhat Sabeeh

    2017-12-01

    Full Text Available The negative effect of acidic attack on the properties of concrete and cement mortar is a topic of increasing significance in the recent years. Many attempts has occurred to mitigate this negative impact by improving the properties of concrete and increase resistance to acids by using additives. The present study includes treatment of sand by alkaline material and examine the effect of treatment on cement mortar resistance towards hydrochloric and sulfuric acid. Results show that sand treatment by alkaline material significantly enhance mortar ability to resist acids. In terms of loss weight, the maximum weight rate gain was 25.54% for specimens immersed in Hydrochloric acid with water cement ratio 40%. For specimens immersed in HCl, the average gain in compressive strength is (20.15-19.433% for w/c (40-45% respectively. The average gain in modulus of rupture toward the influence of H2SO4 is (18.37–17.99% for w/c (40-45%, respectively.

  6. The transformation of waste Bakelite to replace natural fine aggregate in cement mortar

    Directory of Open Access Journals (Sweden)

    Nopagon Usahanunth

    2017-06-01

    Full Text Available Bakelite material has been used to produce the various components for cars and consumer goods industry in Thailand. The growth of Bakelite consumption increases Bakelite waste. Bakelite waste is prohibited from disposing of direct landfilling and open burning because of the improper disposal and emission reasons. A large amount of this waste needs the large safe space of warehouse area for keeping which becomes a waste management problem. Size reduction by milling machine is helpful for waste handling and storing, however, the post-milling waste Bakelite plastic utilization shall be studied to maintain the waste storing capacity. There are some studies of the milling machine used for waste plastic size reduction. However, the particular study of milling machine application for waste size reduction and its milling waste utilization is still insufficient in Thailand. The purpose of this research is the use of waste Bakelite aggregate milling machine for Bakelite waste size reduction and use of the post-milling waste Bakelite as a fine aggregate to replace natural sand material in cement mortar. The waste Bakelite fine aggregate (WBFA was mixed in cement mortar mixture with the proportion 0% 20% 40% 60% 80% and 100% by volume for cement mortar sample preparation. The mortar sample was tested for compressive strength follow ASTM standard. The compressive test result of mortar samples will be compared between conventional mortar (0% WBFA and waste Bakelite mortar (WBM as well as comparing with the mortar standard. From an analysis of the sample test data found that the WBFA content in cement mortar mixture can predict the strength of WBM. The compressive strength of WBM at 28 days age with the fraction of WBFA is not exceeded 11.03%, and 23.08% respectively can be met the mortar standard according to the equation. The utilization of WBM to develop mortar non-structural mortar product can be usable from a technical point of view.

  7. Effect of cement fineness and polycarboxylate dosage on the rheological and mechanical behavior of a mortar

    Directory of Open Access Journals (Sweden)

    Zahia Didouche

    2018-01-01

    Full Text Available The use of certain organic additives in the production of mortar and concrete influences the workability and the hydration kinetic of mortar. This results in a modification of some properties, namely rheological behavior and mechanical strength. The objective of this work is to evaluate the rheological and mechanical behavior of a mortar by varying the fineness of the cement and using the superplasticizer Polycarboxylate.

  8. THz Properties of Adhesives

    Science.gov (United States)

    Stübling, E.; Gomell, L.; Sommer, S.; Winkel, A.; Kahlmeyer, M.; Böhm, S.; Koch, M.

    2018-06-01

    We determined the THz properties of 12 different adhesives which are mainly used for industrial purposes. The adhesives applied can be classified according to their chemical structure: epoxy resins, acrylic resins, and polyurethane based materials. This work represents a basis for future studies, which will concentrate on aging effects, including the absorption of water of adhesive joints. Thus, the dielectric properties of the unaged adhesives are investigated and the results of these measurements are described herein.

  9. Reuse of waste of glass wool in the production of mortar

    International Nuclear Information System (INIS)

    Vieira, P.L.C.; Santos, N.A.; Louzada, D.M.; Araujo, G.S.; Della, V.P.

    2014-01-01

    In recent years, the incorporation of alternative materials, especially waste, in mortars and concretes has become a common practice in the building industry. Against this background, this paper seeks to examine the possibility of using waste glass wool resulting from the steel industry in mortars in partial replacement the thin fraction of sand. To the knowledge of their chemical and mineralogical composition, the waste was subjected to x-ray fluorescence and diffraction assays. Mortars with different percentages of incorporation of waste were produced and performed flow test assays, Water Absorption by capillarity, compressive strength and compressive flexural strength. The results were compared with a reference mortar without residue. (author)

  10. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  11. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    . As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  12. Recycling alternatives of converter slag in concrete and mortars

    International Nuclear Information System (INIS)

    Amorim, Aldo Siervo de

    2000-01-01

    The objective of this work is the study of the use of a residue of a steel plant (COSIPA-SP), constituted by magnetite, in components of the civil construction, aiming to increase the recycling and, consequently, to decrease the impact of that residue in the environment. To reach this objective, additions of this residue were tested in the formulation of concrete with the purpose of radiation shielding, as pellets in coarse aggregate, and as substitute of the fine fraction of sand in the composition of a coating mortar. The concrete produced with purpose of radiation shielding showed that for small residue additions (up to 30%), there was not significant variation in the mechanical properties, nor in the attenuation properties to the radiation. Therefore, it did not justify its addition for purpose of heavy concrete. The results obtained on pelletizing process show that the obtained pellets presented value of specific gravity (2,75 g.cm -3 ) very close to the one of the common crushed stone (2,55 g.cm -3 ), however, they presented a low resistance to the compression, (0,2 KN) for the pellets when compared to regular crushed stones (5,8 KN). These results show that its use could commit the mechanical resistance of the concrete without bringing any advantage on density increase or increment of radiation attenuation. The mortars produced by the addition of the fine residue in substitution to the sand, showed an improvement in the retention of water in green (95%), in comparison to the produced without residue (41%). Also, for ali the tested proportions of substitutions, the same resistance to the compression (approximately 40 MPa) was achieved The results of the leaching and solubility tests showed that even in case of largest amount of substitution of sand for residue (14,55%), there were not great variations on the analyzed elements in the extract, allowing to conclude that the residue behaved satisfactorily to the mortar. Its use as part of mortar composition

  13. Particle adhesion and removal

    CERN Document Server

    Mittal, K L

    2015-01-01

    The book provides a comprehensive and easily accessible reference source covering all important aspects of particle adhesion and removal.  The core objective is to cover both fundamental and applied aspects of particle adhesion and removal with emphasis on recent developments.  Among the topics to be covered include: 1. Fundamentals of surface forces in particle adhesion and removal.2. Mechanisms of particle adhesion and removal.3. Experimental methods (e.g. AFM, SFA,SFM,IFM, etc.) to understand  particle-particle and particle-substrate interactions.4. Mechanics of adhesion of micro- and  n

  14. Calibration of modified parallel-plate rheometer through calibrated oil and lattice Boltzmann simulation

    DEFF Research Database (Denmark)

    Ferraris, Chiara F; Geiker, Mette Rica; Martys, Nicos S

    2007-01-01

    inapplicable here. This paper presents the analysis of a modified parallel plate rheometer for measuring cement mortar and propose a methodology for calibration using standard oils and numerical simulation of the flow. A lattice Boltzmann method was used to simulate the flow in the modified rheometer, thus...

  15. Carbon fibre-reinforced, alkali-activated slag mortars

    Directory of Open Access Journals (Sweden)

    Garcés, P.

    2007-12-01

    Full Text Available The paper describes the effect of carbon fibre on alkaliactivated slag mortar (AAS mechanical strength, volume stability and reinforcing steel corrosion, compared to its effect on the same properties in Portland cement (PC properties. Mechanical strength and volume stability tests were performed as set out in the respective Spanish UNE standards. The corrosion rate of steel embedded in the specimens studied was determined from polarization resistance analysis. One of the findings of the study performed was that carbon fibre failed to improve AAS or CP mortar strength. As far as volume stability is concerned, the inclusion of carbon fibres in AAS with a liquid/solid ratio of 0.5 reduced drying shrinkage by about 50%. The effect of carbon fibre on PC mortars differed from its effect on AAS mortars. Studies showed that in the presence of carbonation, steel corrosion reached higher levels in carbon-fibre reinforced AAS mortars; the inclusion of 1% carbon fibre improved corrosion resistance perceptibly in these same mortars, however, when exposed to chloride attack.Se ha estudiado el efecto de la incorporación de fibras de carbón en el comportamiento mecánico, estabilidad de volumen y nivel de corrosión de la armadura en morteros de escorias activadas alcalinamente (AAS. Se evalúa la influencia de las fibras de carbón en el comportamiento de morteros alcalinos en comparación con el efecto que producen en morteros de Portland (CP. Los ensayos mecánicos y de estabilidad de volumen se han realizado según lo establecido en la norma UNE que los regula. Se ha utilizado la técnica de la Resistencia a la Polarización para determinar la velocidad de corrosión del acero embebido en las muestras estudiadas. Como consecuencia del estudio realizado, se ha podido concluir que la adición de fibras de carbón a morteros de AAS y CP no mejora las características resistentes de los mismos. En relación con la estabilidad de volumen, la incorporación de

  16. Influence of moisture condition on chloride diffusion in partially saturated ordinary Portland cement mortar

    NARCIS (Netherlands)

    Zhang, Y.; Zhang, M.; Ye, G.

    2018-01-01

    Experiments have been carried out to study the influence of moisture condition, including moisture content and its distribution, on the chloride diffusion in partially saturated ordinary Portland cement mortar. The mortar samples with water-to-cement (w/c) ratios of 0.4, 0.5 and 0.6, cured for 1

  17. Experimental study of chloride diffusivity in unsaturated ordinary Portland cement mortar

    NARCIS (Netherlands)

    Zhang, Y.; Ye, G.; Santhanam, M.

    2017-01-01

    Experiments are carried out to investigate the chloride diffusivity in partially saturated ordinary Portland cement mortars with water-to-cement (w/c) ratios of 0.4, 0.5 and 0.6. Based on resistivity measurement and Nernst-Einstein equation, the chloride diffusivities of cement mortars at various

  18. Drying Shrinkage of Mortar Incorporating High Volume Oil Palm Biomass Waste

    Science.gov (United States)

    Shukor Lim, Nor Hasanah Abdul; Samadi, Mostafa; Rahman Mohd. Sam, Abdul; Khalid, Nur Hafizah Abd; Nabilah Sarbini, Noor; Farhayu Ariffin, Nur; Warid Hussin, Mohd; Ismail, Mohammed A.

    2018-03-01

    This paper studies the drying shrinkage of mortar incorporating oil palm biomass waste including Palm Oil Fuel Ash, Oil Palm Kernel Shell and Oil Palm Fibre. Nano size of palm oil fuel ash was used up to 80 % as cement replacement by weight. The ash has been treated to improve the physical and chemical properties of mortar. The mass ratio of sand to blended ashes was 3:1. The test was carried out using 25 × 25 × 160 mm prism for drying shrinkage tests and 70 × 70 ×70 mm for compressive strength test. The results show that the shrinkage value of biomass mortar is reduced by 31% compared with OPC mortar thus, showing better performance in restraining deformation of the mortar while the compressive strength increased by 24% compared with OPC mortar at later age. The study gives a better understanding of how the biomass waste affect on mortar compressive strength and drying shrinkage behaviour. Overall, the oil palm biomass waste can be used to produce a better performance mortar at later age in terms of compressive strength and drying shrinkage.

  19. The Roman mortars used in the construction of the Ponte di Augusto (Narni, Italy)

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš; Fratini, F.; Frankeová, Dita; Slížková, Zuzana

    2013-01-01

    Roč. 38, č. 1 (2013), s. 1117-1128 ISSN 0950-0618 R&D Projects: GA ČR(CZ) GBP105/12/G059 Institutional support: RVO:68378297 Keywords : historic mortar * roman mortar * Narni bridge Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.265, year: 2013

  20. Influence of Chloride-Ion Adsorption Agent on Chloride Ions in Concrete and Mortar

    Directory of Open Access Journals (Sweden)

    Gai-Fei Peng

    2014-04-01

    Full Text Available The influence of a chloride-ion adsorption agent (Cl agent in short, composed of zeolite, calcium aluminate hydrate and calcium nitrite, on the ingress of chloride ions into concrete and mortar has been experimentally studied. The permeability of concrete was measured, and the chloride ion content in mortar was tested. The experimental results reveal that the Cl agent could adsorb chloride ions effectively, which had penetrated into concrete and mortar. When the Cl agent was used at a dosage of 6% by mass of cementitious materials in mortar, the resistance to the penetration of chloride ions could be improved greatly, which was more pronounced when a combination of the Cl agent and fly ash or slag was employed. Such an effect is not the result of the low permeability of the mortar, but might be a result of the interaction between the Cl agent and the chloride ions penetrated into the mortar. There are two possible mechanisms for the interaction between the Cl agent and chloride ion ingress. One is the reaction between calcium aluminate hydrate in the Cl agent and chloride ions to form Friedel’s salt, and the other one is that calcium aluminate hydrate reacts with calcium nitrite to form AFm during the early-age hydration of mortar and later the NO2− in AFm is replaced by chloride ions, which then penetrate into the mortar, also forming Friedel’s salt. More research is needed to confirm the mechanisms.

  1. Self-healing of lime based mortars : Microscopy observations on case studies

    NARCIS (Netherlands)

    Lubelli, B.; Nijland, T.G.; Van Hees, R.P.J.

    2011-01-01

    Lime mortars have, up to a certain extent, a self-healing capacity which may contribute to their durability. Self-healing in lime mortars consists of a process of dissolution, transport and re-precipitation of calcium compounds to heal cracks and fissures. The spontaneous occurrence of self-healing

  2. Self-healing of lime based mortars: Microscopy observations on case studies

    NARCIS (Netherlands)

    Lubelli, B.; Nijland, T.G.; Hees, R.P.J. van

    2011-01-01

    Lime mortars have, up to a certain extent, a self-healing capacity which may contribute to their durability. Self-healing in lime mortars consists of a process of dissolution, transport and re-precipitation of calcium compounds to heal cracks and fissures. The spontaneous occurrence of self-healing

  3. Repair mortars for historic masonry : Effects of the binder choice on durability

    NARCIS (Netherlands)

    Groot, C.J.W.P.

    2016-01-01

    Factors affecting the design of repair mortars for historic masonry are: the type of masonry, the condition of the masonry and the exposure conditions. Especially in case of low-strength masonry exposed to heavy rain and high salt contents the design of a repair mortar may be a challenge. The most

  4. Effect of MHEC on evaporation and hydration characteristics of glue mortar

    NARCIS (Netherlands)

    Faiyas, A.P.A.; Erich, S.J.F.; Huinink, H.P.; Adan, O.C.G; Nijland, T.G.

    2016-01-01

    The influence of methylhydroxyethylcellulose (MHEC) on both moisture distribution and hydration characteristics of glue mortar using nuclear magnetic resonance imaging (NMR) is investigated. MHEC is added to glue mortar in order to control the drying rate by increasing the open time. Besides drying,

  5. Influence of recycled fine aggregates on the resistance of mortars to magnesium sulfate attack

    International Nuclear Information System (INIS)

    Lee, Seung-Tae

    2009-01-01

    The influence of recycled fine aggregates, which had been reclaimed from field-demolished concretes, on the resistance of mortar specimens to magnesium sulfate attack was investigated. Mortar specimens were prepared with recycled fine aggregates at different replacement levels (0%, 25%, 50%, 75% and 100% of natural fine aggregate by mass). The mortar specimens were exposed to 4.24% magnesium sulfate solution for about 1 year at ambient temperature, and regularly monitored for visual appearance, compressive strength loss and expansion. Additionally, in order to identify products of magnesium sulfate attack, mortar samples incorporating 0%, 25% and 100% replacement levels of the recycled fine aggregates were examined by X-ray diffraction (XRD) technique. Experimental results confirmed that the use of recycled fine aggregates up to a maximum 50% replacement level is effective under severe magnesium sulfate environment, irrespective of type of recycled fine aggregates. However, the worse performance was observed in mortar specimens incorporating 100% replacement level. It was found that the water absorption of recycled fine aggregates affected deterioration of mortar specimens, especially at a higher replacement level. XRD results indicated that the main cause of deterioration of the mortar specimens was primarily due to the formation of gypsum and thaumasite by magnesium sulfate attack. In addition, it appeared that the conversion of C-S-H into M-S-H by the attack probably influenced mechanical deterioration of mortar specimens with recycled fine aggregates.

  6. Influence of light masonry mortar on the thermal insulation of a solid brick wall

    Energy Technology Data Exchange (ETDEWEB)

    Kupke, C

    1980-12-01

    For calculations of the thermal insulation of structural components according to DIN 4108 and to the Thermal Insulation Ordinance, characteristic data of thermal conductivity are used which are contained in DIN 4108 and in the Bundesanzeiger in Supplements to the publication of material characteristics for the calculation of thermal insulation according to the Thermal Insulation Ordinance. For masonry, this value is equivalent to the thermal conductivity of the bricks, including mortar joints. The mortar considered is standard mortar, group II, according to DIN 1053. In the last few years, in order to improve the thermal insulation, mortars of low thermal conductivity and low volume weight - so-called light masonry mortars - have been used to an increasing extent. The improvement in thermal conductivity as compared with standard mortar is referred to as ..delta..lambda; it depends mostly on the thermal conductivity of the light mortar and the bricks. In the article, the laws governing the influence of light masonry mortar on the thermal insulation of masonry of solid bricks and solid blocks are reviewed.

  7. Water extraction out of mortar during brick laying: A NMR study

    NARCIS (Netherlands)

    Brocken, H.J.P.; Spiekman, M.E.; Pel, L.; Kopinga, K.; Larbi, J.A.

    1998-01-01

    The water extraction out of mortar during brick laying was studied using nuclear magnetic resonance. The experiments show that using a fired-clay brick, the water is extracted out of the mortar within 3 minutes, whereas in the case of a sand-lime brick this takes about 10 minutes. Prewetting a

  8. Water extraction out of mortar during brick laying : a NMR study

    NARCIS (Netherlands)

    Brocken, H.J.P.; Spiekman, M.E.; Kopinga, K.; Larbi, J.A.

    1998-01-01

    The water extraction out of mortar during brick laying was studied using nuclear magnetic resonance. The experiments show that using a fired-clay brick, the water is extracted out of the mortar within 3 minutes, whereas in the case of a sand-lime brick this takes about 10 minutes. Prewetting a

  9. Economic Analysis of Small Scale Forest-Based Mortar and Pestles ...

    African Journals Online (AJOL)

    The problems militating against the production of mortar and pestles in the area were high transportation cost, high cost of tools, poor weather condition, poor road network, finance and marketing problems. To bring about sustainable production and enhance the level of profitability from production of mortar and pestle, there ...

  10. 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.

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

    Science.gov (United States)

    Zhao, Xiao; Lim, Siong-Kang; Tan, Cher-Siang; Li, Bo; Ling, Tung-Chai; Huang, Runqiu; Wang, Qingyuan

    2015-01-30

    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.

  12. 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

  13. Enhanced H2/CH4 and H2/CO2 Separation by Carbon Molecular Sieve Membrane Coated on Titania Modified Alumina Support: Effects of TiO2 Intermediate Layer Preparation Variables on Interfacial Adhesion.

    Czech Academy of Sciences Publication Activity Database

    Tseng, H.-H.; Wang, Ch.-T.; Zhuang, G.-L.; Uchytil, Petr; Řezníčková Čermáková, Jiřina; Setničková, Kateřina

    2016-01-01

    Roč. 510, JUL 15 (2016), s. 391-404 ISSN 0376-7388 Grant - others:NSC(TW) NSC100-2221-E- 040-004-MY3 Institutional support: RVO:67985858 Keywords : carbon membrane * intermediate layer * adhesion Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 6.035, year: 2016

  14. 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.

  15. 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.

  16. Study of mortars with industrial residual plastic scales

    Directory of Open Access Journals (Sweden)

    Magariños, O. E.

    1998-06-01

    Full Text Available This work proposes the utilization of industrial residues of PET (Polyethylene Terephtalate as a partial substitute of arids (sand in mortar making for construction components. Therefore, the environmental impact of large volumes of plastic of urban residues could be decreased. When PET scales were added to mortars in partial replacement of sand, lower unitary weight, acceptable absorption and resistances according to international specifications were achieved. Mortars with 66% of sand replacement by scales and without any additive, showed optimal characteristics to be used in concret block manufacturing.

    Este trabajo de investigación se desarrolla a partir de la hipótesis de utilizar los desechos post-industriales de PET (Tereftalato de Polietileno como sustituto de áridos (arena, ingrediente de morteros, en la fabricación de componentes constructivos. En dicho trabajo se estudian las propiedades físico-químicas de distintos morteros en los que se reemplazó el contenido de árido por escamas de plástico en distintas proporciones. Se compararon y evaluaron las propiedades físico-mecánicas de los morteros en estudio con los convencionales mediante ensayos de resistencia a la flexión, compresión, absorción, durabilidad y microfotografías por barrido electrónico. Estos estudios determinaron que el agregado de PET en morteros puede ser usado como un posible sustituto de áridos, ya que se obtuvieron morteros con 66% de reemplazo de arena por escamas que presentaron menor peso unitario, absorción aceptable y resistencias acordes a las exigidas por normas.

  17. 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

  18. 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.

  19. The influence of hardening conditions on the properties of masonry cement mortar prisms made in brick moulds

    NARCIS (Netherlands)

    Bertram, G.; Lourenco, P.B.; Hasseltine, B.A.; Vasconseles, G.

    2014-01-01

    One aspect of our investigation into the spacing of movement joints involved the short and long term deformation of mortar embedded in masonry. In this research the influence of hardening conditions on the physical and mechanical properties of masonry cement mortar [M5] were studied. Mortar prisms

  20. Self-flowing mortar for ferrocement in strengthening applications

    Directory of Open Access Journals (Sweden)

    Shamir Sakir

    2016-09-01

    Full Text Available Ferrocement technology is becoming more and more important nowadays for strengthening and retrofitting of concrete structures mainly due to its inherent strength properties. However, its labour intensive nature makes it undesirable for rapid strengthening works. In narrow spaces, strengthening with conventional ferrocement is very critical and also time consuming. Self-flowing mortar (SFM could be used with this technology to overcome these limitations. This article discusses the applicability of SFM in ferrocement technology. The aim of this study is to summarize available knowledge on SFM to make it feasible for optimization in different industrial applications.

  1. Measurement of mortar permittivity during setting using a coplanar waveguide

    International Nuclear Information System (INIS)

    Juan-García, P; Torrents, J M

    2010-01-01

    A sensor based on a coplanar waveguide structure was designed to perform non-destructive tests for material characterization in which the measurement can be done only on one side of the sample. The measurements were compared with the impedance of a capacitor filled with the same material. The permittivity and insertion loss of the sensor showed valuable information about the setting process of a mortar slab during the first 28 days of the hardening process, and a good correlation between both measurements was obtained, so the proposed setup can be useful for structural surveillance and moisture detection in civil structures

  2. Axial compression behavior of concrete masonry wallettes strengthened with cement mortar overlays

    Directory of Open Access Journals (Sweden)

    F. L. De Oliveira

    Full Text Available This paper presents the results of a series of axial compression tests on concrete block wallettes coated with cement mortar overlays. Different types of mortars and combinations with steel welded meshes and fibers were tested. The experimental results were discussed based on different theoretical approaches: analytical and Finite Element Method models. The main conclusions are: a the application of mortar overlays increases the wall strength, but not in a uniform manner; b the strengthening efficiency of wallettes loaded in axial compression is not proportional to the overlay mortar strength because it can be affected by the failure mechanisms of the wall; c steel mesh reinforced overlays in combination with high strength mortar show better efficiency, because the steel mesh mitigates the damage effects in the block wall and in the overlays themselves; d simplified theoretical methods of analysis as described in this paper can give satisfactory predictions of masonry wall behavior up to a certain level.

  3. Continuous monitoring of setting and hardening of mortar using FBG sensors

    Science.gov (United States)

    Lima, H.; Ribeiro, R.; Nogueira, R.; Silva, L.; Abe, I.; Pinto, J. L.

    2007-05-01

    The use of fibre Bragg grating sensors to study mortars' dimensional variations during the setting process is reported. When determining a mortar's potential to fissure, it's important to know its total retraction. This means it is necessary to know not only the mortar's retraction after hardened, but also to know how much it retracts during the plastic phase. This work presents a technique which allows to measure dimensional variations, either expansion or retraction, during the whole setting process. Temperature and strain evolution during both plastic and hardened phase of the mortar were obtained, allowing the determination of dimensional variations and setting times. Due to its high-speed, ease of implementation and low operation costs, this technique will allow to get a deeper knowledge of the effects of several additives on the mortar's behaviour, allowing to improve its mechanical properties through the determination of the proper chemical composition.

  4. Physical and mechanical properties of cement mortar made with brick waste

    Directory of Open Access Journals (Sweden)

    Mohamed Guendouz

    2018-01-01

    Full Text Available The development of new building materials is a current problem where researchers are trying to find the right materials for each region and returning cheapest countries. Recycling and recovery of waste are now considered as a promising solution to meet the deficit between production and consumption and protecting the environment. This work focused on the study of the effect of brick waste in the production of cement mortar with substitution rates ranging from 5-30% by weight of cement and to compare its performance with fresh and hardened state with ordinary mortar considered as control mortar. Compressive and tensile strengths up to 28 days of age were compared with those of controlled mortar. Water absorption was also measured at 28 days of age. The test results indicate the beneficial effect of brick waste powder on performance of cement mortar with an optimum of 15% of cement weight substitution.

  5. HEAT INSULATING LIME DRY MORTARS FOR FINISHING OF WALLS MADE OF FOAM CONCRETE

    Directory of Open Access Journals (Sweden)

    Loganina Valentina Ivanovna

    2016-05-01

    Full Text Available Different aerated mortars are used for pargeting of walls made of aerated concrete. Though the regulatory documents don’t specify the dependence of plaster density from the density grade of gas-concrete blocks. In case of facing of gas-concrete blocks with the grade D500 using plaster mortars with the density 1400…1600 km/m3 there occurs a dismatch in the values of thermal insulation and vapor permeability of the plaster and base. The authors suggest using dry mortars for finishing of gas-concrete block of the grades D500 и D600, which allow obtaining facing thermal insulating coatings. The efficiency of using four different high-porous additives in the lime dry mortar was compared. They were: hollow glass microspheres, aluminosilicate ash microspheres, expanded vermiculite sand, expanded pearlitic sand. The high efficiency of hollow glass microspheres in heat insulating finishing mortars compared to other fillers is proved.

  6. Statistical approach to predict compressive strength of high workability slag-cement mortars

    International Nuclear Information System (INIS)

    Memon, N.A.; Memon, N.A.; Sumadi, S.R.

    2009-01-01

    This paper reports an attempt made to develop empirical expressions to estimate/ predict the compressive strength of high workability slag-cement mortars. Experimental data of 54 mix mortars were used. The mortars were prepared with slag as cement replacement of the order of 0, 50 and 60%. The flow (workability) was maintained at 136+-3%. The numerical and statistical analysis was performed by using database computer software Microsoft Office Excel 2003. Three empirical mathematical models were developed to estimate/predict 28 days compressive strength of high workability slag cement-mortars with 0, 50 and 60% slag which predict the values accurate between 97 and 98%. Finally a generalized empirical mathematical model was proposed which can predict 28 days compressive strength of high workability mortars up to degree of accuracy 95%. (author)

  7. Energetics of bacterial adhesion

    International Nuclear Information System (INIS)

    Loosdrecht, M.C.M. van; Zehnder, A.J.B.

    1990-01-01

    For the description of bacterial adhesion phenomena two different physico-chemical approaches are available. The first one, based on a surface Gibbs energy balance, assumes intimate contact between the interacting surfaces. The second approach, based on colloid chemical theories (DLVO theory), allows for two types of adhesion: 1) secondary minimum adhesion, which is often weak and reversible, and 2) irreversible primary minimum adhesion. In the secondary minimum adhesion a thin water film remains present between the interacting surface. The merits of both approaches are discussed in this paper. In addition, the methods available to measure the physico-chemical surface characteristics of bacteria and the influence of adsorbing (in)organic compounds, extracellular polymers and cell surface appendages on adhesion are summarized. (author) 2 figs., 1 tab., 50 refs

  8. Radiation-curable adhesives

    International Nuclear Information System (INIS)

    Woods, J.G.

    1992-01-01

    Radiation-curable adhesives may be classified into two broad categories. In the first category, adhesive bonding occurs as a direct result of irradiation. The second category includes pressure-sensitive and hot-melt adhesives, which are composed of linear or lightly cross-linked polymers prepared by a radiation-induced polymerization reaction. This chapter is mainly concerned with radiation-curable adhesives of the first category. The various adhesive types are discussed and adhesive performance is examined, particularly in relation to the chemistry and chemical technology which underlies the individual materials. A description of a limited number of representative applications is included as is an outline of recent developments of curing and dispensing equipment. 268 refs., 14 figs., 13 tabs

  9. The adhesive strength and initial viscosity of denture adhesives.

    Science.gov (United States)

    Han, Jian-Min; Hong, Guang; Dilinuer, Maimaitishawuti; Lin, Hong; Zheng, Gang; Wang, Xin-Zhi; Sasaki, Keiichi

    2014-11-01

    To examine the initial viscosity and adhesive strength of modern denture adhesives in vitro. Three cream-type denture adhesives (Poligrip S, Corect Cream, Liodent Cream; PGS, CRC, LDC) and three powder-type denture adhesives (Poligrip Powder, New Faston, Zanfton; PGP, FSN, ZFN) were used in this study. The initial viscosity was measured using a controlled-stress rheometer. The adhesive strength was measured according to ISO-10873 recommended procedures. All data were analyzed independently by one-way analysis of variance combined with a Student-Newman-Keuls multiple comparison test at a 5% level of significance. The initial viscosity of all the cream-type denture adhesives was lower than the powder-type adhesives. Before immersion in water, all the powder-type adhesives exhibited higher adhesive strength than the cream-type adhesives. However, the adhesive strength of cream-type denture adhesives increased significantly and exceeded the powder-type denture adhesives after immersion in water. For powder-type adhesives, the adhesive strength significantly decreased after immersion in water for 60 min, while the adhesive strength of the cream-type adhesives significantly decreased after immersion in water for 180 min. Cream-type denture adhesives have lower initial viscosity and higher adhesive strength than powder type adhesives, which may offer better manipulation properties and greater efficacy during application.

  10. Evaluation of adhesive penetration of wood fibre by nanoindentation and microscopy

    Science.gov (United States)

    Christopher G. Hunt; Joseph E. Jakes; Warren Grigsby

    2010-01-01

    Adhesives used in wood products sometimes infiltrate, or diffuse into the solid material of, wood cell walls, potentially modifying their properties. These changes in cell wall properties are likely to impact the performance of adhesive bonds. While adhesive infiltration has been observed by multiple methods, the effect on cell wall properties is not well understood....

  11. Synaptic Cell Adhesion

    OpenAIRE

    Missler, Markus; Südhof, Thomas C.; Biederer, Thomas

    2012-01-01

    Chemical synapses are asymmetric intercellular junctions that mediate synaptic transmission. Synaptic junctions are organized by trans-synaptic cell adhesion molecules bridging the synaptic cleft. Synaptic cell adhesion molecules not only connect pre- and postsynaptic compartments, but also mediate trans-synaptic recognition and signaling processes that are essential for the establishment, specification, and plasticity of synapses. A growing number of synaptic cell adhesion molecules that inc...

  12. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  13. Characterization of mudejar mortars from St. Gil Abbot church (Zaragoza, Spain: Investigation of the manufacturing technology of ancient gypsum mortars

    Directory of Open Access Journals (Sweden)

    Igea, J.

    2012-12-01

    Full Text Available This work has been focused on the investigation of the technological procedure of Mudejar mortars applied to the characterization of a group of unaltered samples from an example church of Mudejar architecture of Aragon. The research was carried out using multi-analytical techniques including petrographic study, chemistry and mineralogical analysis. All mortars present a homogeneous composition. The binder is made up of a mixture of gypsum and a very low proportion of lime, while the main components of the aggregate are gypsum and carbonate rock fragments, both in a different thermal state of decomposition. The results have proved that both, binder and aggregates display the same composition in these mortars. These aggregates are the by-product of a grinding process of the previously burnt raw materials which have had a positive influence on the properties of the mortars in improving their quality.

    Este trabajo se ha centrado en la investigación de la tecnología de fabricación de morteros mudéjares mediante la caracterización de un conjunto de muestras inalteradas procedentes de una iglesia representativa de la arquitectura Mudéjar aragonesa. La investigación se llevó a cabo mediante el uso combinado de técnicas analíticas incluyendo el estudio petrográfico y el análisis químico y mineralógico. Todos los morteros presentan una composición constante formada por una mezcla de yeso y cal, en muy baja proporción, como ligante, mientras que el árido está formado por fragmentos de rocas yesíferas y carbonatadas en distinto estado de descomposición térmica. Los resultados confirman que en la fabricación de los morteros, ligante y áridos presentan la misma composición, siendo éstos últimos el subproducto de la misma materia prima calcinada, incorporados para elaborar el mortero, tras un proceso de molienda. Esta característica ha influido positivamente en las propiedades de los morteros, mejorando su calidad.

  14. Adhesives for fixed orthodontic brackets.

    Science.gov (United States)

    Mandall, N A; Millett, D T; Mattick, C R; Hickman, J; Macfarlane, T V; Worthington, H V

    2003-01-01

    Bonding of orthodontic brackets to teeth is important to enable effective and efficient treatment with fixed appliances. The problem is bracket failure during treatment which increases operator chairside time and lengthens treatment time. A prolonged treatment is likely to increase the oral health risks of orthodontic treatment with fixed appliances one of which is irreversible enamel decalcification. To evaluate the effectiveness of different orthodontic adhesives for bonding. Electronic databases: the Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Date of most recent searches: August 2002 (CENTRAL) (The Cochrane Library Issue 2, 2002). Trials were selected if they met the following criteria: randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing two different adhesive groups. Participants were patients with fixed orthodontic appliances. The interventions were adhesives that bonded stainless steel brackets to all teeth except the molars. The primary outcome was debond or bracket failure. Data were recorded on decalcification as a secondary outcome, if present. Information regarding methods, participants, interventions, outcome measures and results were extracted in duplicate by pairs of reviewers (Nicky Mandall (NM) and Rye Mattick (CRM); Declan Millett (DTM) and Joy Hickman (JH2)). Since the data were not presented in a form that was amenable to meta-analysis, the results of the review are presented in narrative form only. Three trials satisfied the inclusion criteria. A chemical cured composite was compared with a light cure composite (one trial), a conventional glass ionomer cement (one trial) and a polyacid-modified resin composite (compomer) (one trial). The quality of the trial reports was generally poor. It is difficult to draw any conclusions from this review, however, suggestions are made for methods of improving future research involving

  15. Experimental analysis of compaction of concrete and mortar

    Science.gov (United States)

    Burlion, Nicolas; Pijaudier-Cabot, Gilles; Dahan, Noël

    2001-12-01

    Compaction of concrete is physically a collapse of the material porous microstructure. It produces plastic strains in the material and, at the same time, an increase of its bulk modulus. This paper presents two experimental techniques aimed at obtaining the hydrostatic response of concrete and mortar. The first one is a uniaxial confined compression test which is quite simple to implement and allows to reach hydrostatic pressures of about 600 MPa. The specimen size is large enough so that concrete with aggregate sizes up to 16 mm can be tested. The second one is a true hydrostatic test performed on smaller (mortar) specimens. Test results show that the hydrostatic response of the material is elasto-plastic with a stiffening effect on both the tangent and unloading bulk moduli. The magnitude of the irreversible volumetric strains depends on the initial porosity of the material. This porosity can be related in a first approximation to the water/cement ratio. A comparison of the hydrostatic responses obtained from the two testing techniques on the same material show that the hydrostatic response of cementitious materials cannot be uncoupled from the deviatoric response, as opposed to the standard assumption in constitutive relations for metal alloys. This feature should be taken into account in the development of constitutive relations for concrete subjected to high confinement pressures which are needed in the modelling of impact problems.

  16. The Effect of Graphene Oxide on Cement Mortar

    Science.gov (United States)

    Kjaernsmo, Henrik; Kakay, Samdar; Fossa, Kjell T.; Gronli, John

    2018-05-01

    This paper investigates the effect of water dispersed- and powder Graphene oxide (GO) nanoparticle on fresh cement mortar, microstructure and mechanical strength after 3,7, and 28 days of curing. These properties were studied by treating the cement mortar with 0.03 wt%, 0.05 wt%, and 0.2 wt% GO of the cement weight combined with 0.8wt % polycarboxylate superplasticizer. The results show that the workability decreases as increasing the content of water dispersed GO. The heat of hydration is increased for both types of GO systems. The percent air content in 0.03 wt% and 0.05 wt% GO is almost constant, but increased from 3.2 % to 4.9 % in 0.2 wt% water dispersed GO. The increased air content has effect on poor compaction and workability. GO has the potential of accelerating the hydration process and enhance the early mechanical strength (3 and 7 days), but the workability seems to diminish the mechanical strength after 28 days of curing, particularly for the highest content of water dispersed GO. No distinct influence of GO on the microstructure. The overall results showed that the impact of water dispersed GO was found out to be higher than the powder GO.

  17. Coupling nonlinear Stokes and Darcy flow using mortar finite elements

    KAUST Repository

    Ervin, Vincent J.

    2011-11-01

    We study a system composed of a nonlinear Stokes flow in one subdomain coupled with a nonlinear porous medium flow in another subdomain. Special attention is paid to the mathematical consequence of the shear-dependent fluid viscosity for the Stokes flow and the velocity-dependent effective viscosity for the Darcy flow. Motivated by the physical setting, we consider the case where only flow rates are specified on the inflow and outflow boundaries in both subdomains. We recast the coupled Stokes-Darcy system as a reduced matching problem on the interface using a mortar space approach. We prove a number of properties of the nonlinear interface operator associated with the reduced problem, which directly yield the existence, uniqueness and regularity of a variational solution to the system. We further propose and analyze a numerical algorithm based on mortar finite elements for the interface problem and conforming finite elements for the subdomain problems. Optimal a priori error estimates are established for the interface and subdomain problems, and a number of compatibility conditions for the finite element spaces used are discussed. Numerical simulations are presented to illustrate the algorithm and to compare two treatments of the defective boundary conditions. © 2010 Published by Elsevier B.V. on behalf of IMACS.

  18. Evaluation of Electrochemical Treatment of Chloride Contaminated Mortar Containing GGBS

    Directory of Open Access Journals (Sweden)

    Ki Hong Lee

    2017-01-01

    Full Text Available The present study concerns the influence of cementitious binder on electrochemical treatment of steel embedded in salt contaminated mortar. As binder, ordinary Portland cement (OPC and ground granulated blast furnace slag (GGBS were used and the current density of 250–750 mA/m2 was applied for 4 weeks to complete electrochemical chloride extraction. To evaluate the effect of electrochemical treatment the chloride profile and corrosion behaviour covering chloride concentration, galvanic current density, linear polarization resistance, open circuit potential, and mass loss were measured. An increase in the applied direct current density resulted in a decrease in the chloride concentration at the vicinity of steel, accompanying the mitigated corrosion damage. The performance of electrochemical treatment was more remarkable in mortar containing GGBS presumably due to binding mechanism. However, corrosion damage was more detrimental in GGBS rather than OPC at a given potential, while GGBS had superior corrosion resistance to a corrosive environment and treatment conditions. Therefore, the electrochemical treatment should be conducted prudently to evaluate the corrosion state of embedded steel depending on binder type.

  19. Polymer-Cement Mortar with Quarry Waste as Sand Replacement

    Directory of Open Access Journals (Sweden)

    D. N. Gómez-Balbuena

    2018-01-01

    Full Text Available The activities of carved Quarry extraction generate problems of landscape pollution such is the case of solid waste discharged into open land dumps in central Mexico. This article presents the technological application of this solid waste in a new polymeric material with properties similar to those of a traditional mortar. It is concluded that the polymeric material uses low amounts of cement with respect to the traditional mortar, and it is elaborated with the recycled quarry as they are presented in its granulometry. The polymer used favored a low water/cement ratio (0.3 which did not allow to decrease resistance due to the fine nature of the materials (residues and cement in addition to maintaining the workability of the material. The quarry residue was classified as silt with low plasticity and was characterized by X-ray diffraction and Fluorescence to identify 76% of SiO2, which is why it was used as a stone aggregate even though the fines content was approximately 93%. The maximum compression resistance obtained at 28 days were 8 Mpa with the polymer/solid ratios of 0.10, water/solids of 0.30, and quarry/solids of 0.67. Linear equations were analyzed for more representative values with R squared adjustment.

  20. Syndecan-4 and integrins: combinatorial signaling in cell adhesion

    DEFF Research Database (Denmark)

    Couchman, J R; Woods, A

    1999-01-01

    It is now becoming clear that additional transmembrane components can modify integrin-mediated adhesion. Syndecan-4 is a transmembrane heparan sulfate proteoglycan whose external glycosaminoglycan chains can bind extracellular matrix ligands and whose core protein cytoplasmic domain can signal...... during adhesion. Two papers in this issue of JCS demonstrate, through transfection studies, that syndecan-4 plays roles in the formation of focal adhesions and stress fibers. Overexpression of syndecan-4 increases focal adhesion formation, whereas a partially truncated core protein that lacks the binding...... site for protein kinase C(&agr;) and phosphatidylinositol 4, 5-bisphosphate acts as a dominant negative inhibitor of focal adhesion formation. Focal adhesion induction does not require interaction between heparan sulfate glycosaminoglycan and ligand but can occur when non-glycanated core protein...

  1. Design methodology for nano-engineered surfaces to control adhesion: Application to the anti-adhesion of particles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taekyung [National Center for Optically-Assisted Ultra-High Precision Mechanical Systems, Yonsei University, Seoul 03722 (Korea, Republic of); School of Mechanical Engineering, Yonsei University, Seoul 03722 (Korea, Republic of); Min, Cheongwan [National Center for Optically-Assisted Ultra-High Precision Mechanical Systems, Yonsei University, Seoul 03722 (Korea, Republic of); Jung, Myungki; Lee, Jinhyung; Park, Changsu [National Center for Optically-Assisted Ultra-High Precision Mechanical Systems, Yonsei University, Seoul 03722 (Korea, Republic of); School of Mechanical Engineering, Yonsei University, Seoul 03722 (Korea, Republic of); Kang, Shinill, E-mail: snlkang@yonsei.ac.kr [National Center for Optically-Assisted Ultra-High Precision Mechanical Systems, Yonsei University, Seoul 03722 (Korea, Republic of); School of Mechanical Engineering, Yonsei University, Seoul 03722 (Korea, Republic of)

    2016-12-15

    Highlights: • A design method using the Derjaguin approximation with FEA for low-adhesion surface. • Fabrication of nanostructures with small adhesion forces by presented design method. • Characterization of adhesion force via AFM FD-curve with modified atypical tips. • Verification of low-adhesion of designed surfaces using centrifugal detachment tests. • Investigation of interdependence of hydrophobicity and anti-adhesion force. - Abstract: With increasing demand for means of controlling surface adhesion in various applications, including the semiconductor industry, optics, micro/nanoelectromechanical systems, and the medical industry, nano-engineered surfaces have attracted much attention. This study suggests a design methodology for nanostructures using the Derjaguin approximation in conjunction with finite element analysis for the control of adhesion forces. The suggested design methodology was applied for designing a nano-engineered surface with low-adhesion properties. To verify this, rectangular and sinusoidal nanostructures were fabricated and analyzed using force-distance curve measurements using atomic force microscopy and centrifugal detachment testing. For force-distance curve measurements, modified cantilevers with tips formed with atypical particles were used. Subsequently, centrifugal detachment tests were also conducted. The surface wettability of rectangular and sinusoidal nanostructures was measured and compared with the measured adhesion force and the number of particles remaining after centrifugal detachment tests.

  2. 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.

  3. 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.

  4. The Influence of Biochemical Modification on the Properties of Adhesive Compounds

    OpenAIRE

    Anna Rudawska; Izabela Haniecka; Magdalena Jaszek; Monika Osińska-Jaroszuk

    2016-01-01

    The main objective of this study was to determine the effect of biochemical modification of epoxy adhesive compounds on the mechanical properties of a cured adhesive exposed to various climatic factors. The epoxy adhesive was modified by lyophilized fungal metabolites and prepared by three methods. Additionally, the adhesive compound specimens were seasoned for two months at a temperature of 50 °C and 50% humidity in a climate test chamber, Espec SH 661. The tensile strength tests of the adh...

  5. Adhesive compositions and methods

    Science.gov (United States)

    Allen, Scott D.; Sendijarevic, Vahid; O'Connor, James

    2017-12-05

    The present invention encompasses polyurethane adhesive compositions comprising aliphatic polycarbonate chains. In one aspect, the present invention encompasses polyurethane adhesives derived from aliphatic polycarbonate polyols and polyisocyanates wherein the polyol chains contain a primary repeating unit having a structure:. In another aspect, the invention provides articles comprising the inventive polyurethane compositions as well as methods of making such compositions.

  6. Soy protein adhesives

    Science.gov (United States)

    Charles R. Frihart

    2010-01-01

    In the quest to manufacture and use building materials that are more environmentally friendly, soy adhesives can be an important component. Trees fix and store carbon dioxide in the atmosphere. After the trees are harvested, machinery converts the wood into strands, which are then bonded together with adhesives to form strandboard, used in constructing long-lasting...

  7. 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.

  8. Characterization of historic lime mortars by neutron scattering and mercury porosimetry

    International Nuclear Information System (INIS)

    Zouridakis, N.; Stefanopoulos, K.L.; Treimer, W.

    1999-01-01

    Complete text of publication follows. Lime mortars were commonly used in building from ancient Greek times through to the beginning of the nineteenth century [1]. In the past few years, the increased interest in conservation and restoration of historic monuments requires a better knowledge of the structure and composition of lime mortars resulting from the various additives, as well as the preparation technique each time used. Lime mortars from ancient Greek monuments have been dated by using the radiocarbon method [2]. Furthermore, a wide selection of lime mortars from known historic periods and monuments in Greece has been examined by mercury porosimetry. It was found that their structure depends on the utilization of the monument which come from. In specific, lime mortars coming from residences have more or less the same structure, whereas the preparation technique differs for lime mortars coming from tombs and walls. The weathering effects on the porous system of the mortars are studied by neutron scattering. (author) [1] Brown, P.W., and Clifton, J.R., 'Air pollution and conservation', eds. J. Roswall and S. Aleby, 225 (1988), Elsevier, Amsterdam.; [2] N. Zouridakis, J.F. Sliege, A. Person et al., Archaeometry, 60 (1987) 29

  9. Biopolymers to improve physical properties and leaching characteristics of mortar and concrete: A review

    Science.gov (United States)

    Olivia, M.; Jingga, H.; Toni, N.; Wibisono, G.

    2018-04-01

    The invention of environmentally friendly, high performance, and green material such as biopolymers marked an emerging trend for sustainable construction over the past decades. Biopolymer comprises of natural monomers and synthesized by plants or other organisms. The sustainable, biodegradable, and renewable biopolymers were used in concrete mixes to improve their physical and mechanical properties and durability. The aim of this paper is to provide a brief an overview of the impact of biopolymer addition into concrete and mortar mixes. Many studies on the influence of biopolymer on the properties of concrete and mortar by adding biopolymers at a certain proportion (usually less than one wt.%) to the concrete or mortar mixes, and the heavy metal leaching, rheological, and mechanical properties of the mixes were conducted. Biopolymers included in this review are chitosan (CH), xanthan gum (XG), guar gum (GG), lignosulphonate (LS), and cellulose ethers (CE). Data from previous studies showed that the addition of certain types of biopolymer into concrete and mortar mixes improve workability, water retention, and compressive strength by up to 30 percent. Chitosan strengthens heavy metal encapsulation in the mortar and neutralizes the negative impact of heavy metal on the mortar properties and environment. To sum up, the use of biopolymers improve physical properties and leaching characteristics of mortar and concrete.

  10. Resistance of biofilm-covered mortars to microbiologically influenced deterioration simulated by sulfuric acid exposure

    Energy Technology Data Exchange (ETDEWEB)

    Soleimani, Sahar, E-mail: ssoleima@connect.carleton.ca; Isgor, O. Burkan, E-mail: burkan_isgor@carleton.ca; Ormeci, Banu, E-mail: banu_ormeci@carleton.ca

    2013-11-15

    Following the reported success of biofilm applications on metal surfaces to inhibit microbiologically influenced corrosion, effectiveness and sustainability of E. coli DH5α biofilm on mortar surface to prevent microbiologically influenced concrete deterioration (MICD) are investigated. Experiments simulating microbial attack were carried out by exposing incrementally biofilm-covered mortar specimens to sulfuric acid solutions with pH ranging from 3 to 6. Results showed that calcium concentration in control reactors without biofilm was 23–47% higher than the reactors with biofilm-covered mortar. Formation of amorphous silica gel as an indication of early stages of acid attack was observed only on the control mortar specimens without biofilm. During acidification, the biofilm continued to grow and its thickness almost doubled from ∼ 30 μm before acidification to ∼ 60 μm after acidification. These results demonstrated that E. coli DH5α biofilm was able to provide a protective and sustainable barrier on mortar surfaces against medium to strong sulfuric acid attack. -- Highlights: •Effectiveness of E.coli DH5α biofilm to prevent MICD was studied. •Conditions that lead to MICD were simulated by chemical acidification. •Biofilm-covered mortar specimens were exposed to sulfuric acid solutions. •The presence of biofilm helped reduce the chemically-induced mortar deterioration. •Biofilm remained alive and continued to grow during the acidification process.

  11. Use of limestone obtained from waste of the mussel cannery industry for the production of mortars

    International Nuclear Information System (INIS)

    Ballester, Paloma; Marmol, Isabel; Morales, Julian; Sanchez, Luis

    2007-01-01

    Various types of cement-SiO 2 -CaCO 3 mortar were prepared by replacing quarry limestone aggregate with limestone obtained as a by-product from waste of the mussel cannery industry. The CaCO 3 aggregate consists mainly of elongated prismatic particles less than 4 μm long rather than of the rounded particles of smaller size (2-6 μm) obtained with quarry limestone. The mechanical and structural properties of the mortars were found to be influenced by aggregate morphology. Setting of the different types of mortar after variable curing times was evaluated by scanning electron microscopy (SEM), thermogravimetric analysis (TG) and mercury intrusion porosimetry (MIP) techniques. Mortars with a high content in mussel shell limestone exhibited a more packed microstructure, which facilitates setting of cement and results in improved mortar strength. The enhanced mechanical properties of the new mortars allow the cement content in the final mortar composition to be decreased and production costs to be reduced as a result

  12. Resistance of biofilm-covered mortars to microbiologically influenced deterioration simulated by sulfuric acid exposure

    International Nuclear Information System (INIS)

    Soleimani, Sahar; Isgor, O. Burkan; Ormeci, Banu

    2013-01-01

    Following the reported success of biofilm applications on metal surfaces to inhibit microbiologically influenced corrosion, effectiveness and sustainability of E. coli DH5α biofilm on mortar surface to prevent microbiologically influenced concrete deterioration (MICD) are investigated. Experiments simulating microbial attack were carried out by exposing incrementally biofilm-covered mortar specimens to sulfuric acid solutions with pH ranging from 3 to 6. Results showed that calcium concentration in control reactors without biofilm was 23–47% higher than the reactors with biofilm-covered mortar. Formation of amorphous silica gel as an indication of early stages of acid attack was observed only on the control mortar specimens without biofilm. During acidification, the biofilm continued to grow and its thickness almost doubled from ∼ 30 μm before acidification to ∼ 60 μm after acidification. These results demonstrated that E. coli DH5α biofilm was able to provide a protective and sustainable barrier on mortar surfaces against medium to strong sulfuric acid attack. -- Highlights: •Effectiveness of E.coli DH5α biofilm to prevent MICD was studied. •Conditions that lead to MICD were simulated by chemical acidification. •Biofilm-covered mortar specimens were exposed to sulfuric acid solutions. •The presence of biofilm helped reduce the chemically-induced mortar deterioration. •Biofilm remained alive and continued to grow during the acidification process

  13. Effect of Polypropylene and Basalt Fiber on the Behavior of Mortars for Repair Applications

    Directory of Open Access Journals (Sweden)

    Chaohua Jiang

    2016-01-01

    Full Text Available The fresh, mechanical, and durability properties of the polypropylene fiber-reinforced mortar (PP FRM and the basalt fiber-reinforced mortar (BFRM with various fiber contents were tested in this paper. The test results show that the presence of polypropylene (PP fiber and basalt fiber (BF in the mortar reduces the initial slump flow and increases the slump flow loss rate. The bond strength and flexural strength of fiber-reinforced mortar (FRM are improved, whereas no obvious improvement on the compressive strength has been observed. Compared with the control mortar, the bond strength of PP FRM and BFRM reinforced with 0.6 kg/m3, 1.6 kg/m3, and 2.6 kg/m3 fiber increases by 16.60%–28.80% and 10.60%–21.40%, respectively. Furthermore, FRM shows lower drying shrinkage, superior abrasion resistance, water impermeability, and freeze-thaw resistance compared with the control mortar. The abrasion resistance strength of PP FRM and BFRM is 77.30% and 38.65% more than the control mortar with 2.6 kg/m3 fiber content. Therefore, PP FRM and BFRM are suitable to be utilized as repair materials, especially in repairing hydraulic structures surfaces with excellent bond strength and abrasion resistance.

  14. Carbonation kinetics in roman-like lime mortar

    Directory of Open Access Journals (Sweden)

    Sánchez-Moral, S.

    2004-09-01

    Full Text Available The kinetic parameterisation of lime mortar carbonation is a useful technique for understanding ancient building methods and the long-lived physical-chemical stability of roman monuments. Portlandite (Ca(OH2 binders harden in the air on contact with atmospheric CO2, producing CaCO3. Water evaporation and the presence of silicate aggregates have a three-fold effect: prompting the development of a pore system that permits CO2, self-diffusion, reducing shrinkage and cracking during drying and (possibly giving rise to subsequent pozzolanic reactions. The present survey involved air-hardening a series of roman-like lime mortars which differed in terms of: (i type of aggregate, volcanic tephra and arkose; (ii aggregate/binder ratio, 1:2 as used in the catacombs and 1:4 as found in standard roman construction and (iii temperature, the 17 ºC prevailing in underground environments and the 30 ºC typical of warm Mediterranean areas. The analyses that provided the most useful information were performed in a classic X-ray diffractometer adapted to accommodate an author-designed chamber in which temperature control was achieved by an internal refrigerant and a PID-governed electrical heater Additional data were obtained with DTA and environmental scanning electron microscopy (ESEM. The tests conducted on the Roman-like lime mortars manufactured for the experiment showed that the hardening temperature is a critical factor in the initial phases of carbonation. Calcite precipitation rates and total mineral precipitation increased with temperature, but fell very quickly as calcite precipitated. In theoretical calculations assuming an open reactor with continuous CO2, input, total calcitisation time was found to be 156 m in. at 30 ºC and 175 min. at 17 ºC, whilst in the mortars actually hardened in the experimental part of the study, calcitisation gradually blocked the flow or CO2, gas into the

  15. AMS radiocarbon dating of mortar: The case study of the medieval UNESCO site of Modena

    Energy Technology Data Exchange (ETDEWEB)

    Carmine, Lubritto [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche & CIRCE lab, Seconda Università degli Studi di Napoli, I-81100 Caserta (Italy); Caroselli, Marta; Lugli, Stefano [Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, I-41100 Modena (Italy); Marzaioli, Fabio [Dipartimento di Matematica e Fisica & CIRCE lab, Seconda Università degli Studi di Napoli, I-81100 Caserta (Italy); Nonni, Sara [Università degli Studi “Sapienza”, Dipartimento di Scienze della Terra, I-00185 Roma (Italy); Marchetti Dori, S. [Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, I-41100 Modena (Italy); Terrasi, Filippo [Dipartimento di Matematica e Fisica & CIRCE lab, Seconda Università degli Studi di Napoli, I-81100 Caserta (Italy)

    2015-10-15

    The carbon dioxide contributing to binder formation during the set of a lime mortar reflects the atmospheric {sup 14}C content at the time of construction of a building. For this reason, the {sup 14}C dating of mortars is used with increasing frequencies in archaeological and architectural research. Mortars, however, may also contain carbonaceous contaminants potentially affecting radiocarbon dating. The Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) of the Second University of Naples (SUN) has recently obtained some promising results in mortar radiocarbon dating thanks to the development of a procedure (i.e. CryoSoniC/Cryo2SoniC) aiming to eliminate exogenous C contamination that may occur in a mortar. The construction history of the UNESCO World Heritage Site of Modena (Italy) is still controversial and represents a challenging case study for the application of absolute dating methodologies for different reasons. From the point of view of {sup 14}C dating, for example, given the high percentage of carbonate aggregates composing these samples, Modena mortars represent an experimental test particularly indicative of exogenous carbon sources suppression ensuring methodology accuracy. In this paper several AMS Radiocarbon dates were carried out on lime lumps with the aim to: (i) verify procedure accuracy by a comparison of the results obtainable from lime lumps dated after different treatments (i.e. bulk lime lumps vs. CryoSoniC purified lime lumps); (ii) compare different building phases absolute chronology for the medieval UNESCO site of Modena, with that assumed by historical sources in order to assess preliminary the {sup 14}C dating feasibility for of the site. Historical temporal constraints and mortar clustering, based on petrography, have been applied to define a temporal framework of the analyzed structure. Moreover, a detailed petrographic characterization of mortars was used both as a preliminary tool for the choice of samples

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

    International Nuclear Information System (INIS)

    Ling, Tung-Chai; Poon, Chi-Sun

    2011-01-01

    Graphical abstract: Display Omitted Highlights: → A recycling/treatment process to remove lead on funnel glass surface is described. → Utilizing recycled funnel glass in mortar can reduce hazardous CRT glass wastes. → Effects of CRT glass content on the properties of cement mortar are studied. → Fly ash can effectively mitigate ASR expansion of mortar even at 100% glass content. → Alkaline medium in cement matrix successfully prevented the leaching of lead. - Abstract: 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.

  17. The increase of compressive strength of natural polymer modified concrete with Moringa oleifera

    Science.gov (United States)

    Susilorini, Rr. M. I. Retno; Santosa, Budi; Rejeki, V. G. Sri; Riangsari, M. F. Devita; Hananta, Yan's. Dianaga

    2017-03-01

    Polymer modified concrete is one of some concrete technology innovations to meet the need of strong and durable concrete. Previous research found that Moringa oleifera can be applied as natural polymer modifiers into mortars. Natural polymer modified mortar using Moringa oleifera is proven to increase their compressive strength significantly. In this resesearch, Moringa oleifera seeds have been grinded and added into concrete mix for natural polymer modified concrete, based on the optimum composition of previous research. The research investigated the increase of compressive strength of polymer modified concrete with Moringa oleifera as natural polymer modifiers. There were 3 compositions of natural polymer modified concrete with Moringa oleifera referred to previous research optimum compositions. Several cylinder of 10 cm x 20 cm specimens were produced and tested for compressive strength at age 7, 14, and, 28 days. The research meets conclusions: (1) Natural polymer modified concrete with Moringa oleifera, with and without skin, has higher compressive strength compared to natural polymer modified mortar with Moringa oleifera and also control specimens; (2) Natural polymer modified concrete with Moringa oleifera without skin is achieved by specimens contains Moringa oleifera that is 0.2% of cement weight; and (3) The compressive strength increase of natural polymer modified concrete with Moringa oleifera without skin is about 168.11-221.29% compared to control specimens

  18. Influence of Curing Conditions on Long-Term Compressive Strength of Mortars with Accelerating Admixtures

    Science.gov (United States)

    Pizoń, Jan; Łaźniewska-Piekarczyk, Beata

    2017-10-01

    One of disadvantages of accelerating admixtures usage is possibility of significant decline of long-term compressive strength of concrete in comparison to non-modified one. Described tests were intended to define scale of lowered long-term compressive strength of mortars caused by accelerating admixtures in different curing conditions. Portland cement and blended cement with ground granulated blast furnace slag (GGBFS) addition and four types of non-chloride accelerating agents were used. Compressive strength was tested after 7 up to 360 days. Curing conditions were designed to simulate probable conditions close to reality. Such conditions are simulation of internal concrete elements, external elements cast on start of summer and external elements cast on start of winter. Results had shown that it is invalid to state that every accelerating admixture will cause drop of long-term compressive strength in every conditions and for every cement type. Change of curing conditions even after a long time (in this case half of the year) leads to significant differences in compression strength.

  19. Improving adhesion of seasonings to crackers with hydrocolloid solutions.

    Science.gov (United States)

    Armstrong, Matthew E; Barringer, Sheryl A

    2013-11-01

    Food powders were applied on crackers that had been coated using water, oil, emulsion, sucrose, or hydrocolloid solutions. The hydrocolloids that were used include gellan gum, kappa-carrageenan, methylcellulose, gum karaya, gum tragacanth, gum arabic, guar gum, modified starch, and maltodextrin. Solutions of similar hydrophobicity to the powder gave the greatest adhesion. NaCl, barbecue (BBQ), ranch, and sour cream & onion (SC&O) seasoning showed greatest adhesion with water, cheese powder with an emulsion of 12.5% to 25% oil, and cocoa powder with oil. For NaCl, BBQ, ranch, and SC&O seasoning, hydrocolloids improved the adhesion over using water alone, with gellan gum providing the greatest adhesion. Hydrocolloid structural differences, including the presence or absence of branching, substitution of sugar units, and molecular weight affect water binding and thickening of the hydrocolloid spray that seemed to be significant factors affecting adhesion of powders to the target surface. For cheese powder, hydrocolloids were capable of replacing the oil within an emulsion while improving or maintaining the same level of adhesion, with gum arabic providing the greatest adhesion. For cocoa powder, hydrocolloid solutions were ineffective adhesives due to differences in hydrophilicity that result in insolubility. The effect of hydrocolloid concentration on adhesion was dependent both on the hydrocolloid type and the concentration that is sprayable, with 0.5% being the optimum concentration for most gums. Adhesion using sucrose solutions was determined by particle size and relative hydrophobicity. Increasing sucrose concentration decreased adhesion of smaller particles, but increased adhesion of larger particles. Adhesion of NaCl significantly increased with decreasing NaCl size using oil, water, and sucrose solutions. © 2013 Institute of Food Technologists®

  20. A pulsed field gradient and NMR imaging investigations of the water retention mechanism by cellulose ethers in mortars

    International Nuclear Information System (INIS)

    Patural, Laetitia; Porion, Patrice; Van Damme, Henri; Govin, Alexandre; Grosseau, Philippe; Ruot, Bertrand; Deves, Olivier

    2010-01-01

    The study presented in this paper is devoted to improve the knowledge on the influence of cellulose ethers (CE) on the freshly-mixed mortars water retention. Indeed, this crucial property is the most important imparted by these polysaccharides. One of the assumptions proposed to explain this phenomenon is that CE acts as diffusion barrier to the water. To test this hypothesis, the CE effect on the self-diffusion coefficient of water in solution and on the water mobility between two fresh cement pastes was studied by Nuclear Magnetic Resonance. CE does not significantly modify the water self-diffusion coefficient in CE solution or in admixed cement pastes. Moreover the interdiffusion imaging experiments demonstrated that the water diffusion at the paste/paste interface is not affected by the presence of cellulosic admixture.

  1. Physics of adhesion

    International Nuclear Information System (INIS)

    Gerberich, W W; Cordill, M J

    2006-01-01

    Adhesion physics was relegated to the lowest echelons of academic pursuit until the advent of three seemingly disconnected events. The first, atomic force microscopy (AFM), eventually allowed fine-scale measurement of adhesive point contacts. The second, large-scale computational materials science, now permits both hierarchical studies of a few thousand atoms from first principles or of billions of atoms with less precise interatomic potentials. The third is a microelectronics industry push towards the nanoscale which has provided the driving force for requiring a better understanding of adhesion physics. In the present contribution, an attempt is made at conjoining these separate events into an updating of how theoretical and experimental approaches are providing new understanding of adhesion physics. While all material couples are briefly considered, the emphasis is on metal/semiconductor and metal/ceramic interfaces. Here, adhesion energies typically range from 1 to 100 J m -2 where the larger value is considered a practical work of adhesion. Experimental emphasis is on thin-film de-adhesion for 10 to 1000 nm thick films. For comparison, theoretical approaches from first principles quantum mechanics to embedded atom methods used in multi-scale modelling are utilized

  2. Effect of crushed sand on mortar and concrete rheology

    Directory of Open Access Journals (Sweden)

    Cabrera, O. A.

    2011-09-01

    Full Text Available This article describes an experimental study conducted on fresh mortars and concretes made with crushed sand. The aim of this research was to assess the effect of aggregate particle shape and surface texture as well as dust content on mortar and concrete rheology. The experimental programme also addressed the impact of angular grains on chemical admixture performance and concrete bleeding. The findings showed that the use of crushed sand induces rheological behaviour that differs from the behaviour observed in natural sand and that superplasticisers can improve this behaviour considerably.

    En el presente trabajo se plantea un estudio experimental del estado fresco de morteros y hormigones con arenas de machaqueo, orientado a la evaluación de la incidencia de la forma y textura superficial de los granos del árido fino y del contenido de polvo sobre la reología de las mezclas. El programa experimental comprendió el estudio del estado fresco de hormigones con arenas con partículas angulares, la influencia de este tipo de partículas sobre la efectividad de los aditivos químicos y la evaluación de la influencia de las características físicas del árido fino sobre la exudación. Los resultados muestran que el empleo de arenas de machaqueo provoca un comportamiento reológico diferente al de hormigones con arenas naturales, y que el efecto de los aditivos superfluidificantes mejora notablemente este comportamiento.

  3. Fire Related Temperature Resistance of Fly Ash Based Geopolymer Mortar

    Directory of Open Access Journals (Sweden)

    Jeyalakshmi R.

    2017-01-01

    Full Text Available The study presented in this paper is on the effect of heat treatment on fly ash based geopolymer mortar synthesized from fly ash (Class F –Low lime using alkaline binary activator solution containing sodium hydroxide (18 M and sodium silicate solution (MR 2.0, cured at 80oC for 24 h. 7 days aged specimen heated at elevated temperature (200°C, 400°C, 600°C and 800°C for the sustained period of 2hrs. The TGA/DTA analysis and thermal conductivity measurement as per ASTM C113 were carried out besides the compressive strengths. The thermal stability of the fly ash mortar at elevated temperature was found to be high as reflected in the observed value of f800°C/f30°C being more than 1 and this ratio was raised to about 1.3 with the addition of 2% Zirconium di oxide (ZrO2. No visible cracks were found on the specimens with and without ZrO2 when 800°C was sustained for 4 hrs in smaller specimens of size: 50 mm diameter x 100 mm height and in also bigger size specimens: 22 cm × 11 cm × 7 cm specimens. TGA/DTA analysis of the geopolymer paste showed that the retention of mass was around 90%. The addition of ZrO2 improved thermal resistance. The micro structure of the matrix found to be intact even at elevated temperature that was evident from the FESEM studies.

  4. EB curable laminating adhesives

    International Nuclear Information System (INIS)

    Matsuyama, Asao; Kobayashi, Masahide; Gotoh, Sakiko

    1992-01-01

    New developed solvent free EB curable laminating adhesives have two liquid components, A with hydroxy and acryloyl group, B with isocyanate and acryloyl group in a molecule. These EB laminating adhesives do not need any aging process, which is a big advantage, and are very suitable for environment, safety, and health because of no heating process and solvent free formulas. And we have made basic research about the relation of peel strength or heat seal strength versus Tg of cured film, elongation at break, elastic modulus, and so on. Basic specifications of the new developed adhesives are shown. (author)

  5. Mineralogical and microstructural studies of mortars from the bath complex of the Roman villa rustica near Mosnje (Slovenia)

    International Nuclear Information System (INIS)

    Kramar, Sabina; Zalar, Vesna; Urosevic, Maja; Koerner, Wilfried; Mauko, Alenka; Mirtic, Breda; Lux, Judita; Mladenovic, Ana

    2011-01-01

    This study deals with the characterization of mortars collected from bath complex of the Roman villa rustica from an archeological site near Mosnje (Slovenia). The mortar layers of the mosaics, wall paintings and mortar floors were investigated. A special aggregate consisting of brick fragments was present in the mortars studied. The mineralogical and petrographic compositions of the mortars were determined by means of optical microscopy, X-ray powder diffraction and FTIR spectroscopy. Analysis of aggregate-binder interfaces using SEM-EDS revealed various types of reactivity rims. In order to assess the hydraulic characteristics of the mortars, the acid-soluble fractions were determined by ICP-OES. Furthermore, the results of Hg-porosimetry and gas sorption isotherms showed that mortars with a higher content of brick fragments particles exhibited a higher porosity and a greater BET surface area but a lower average pore diameter compared to mortars lacking this special aggregate. - Highlights: → Mineral and microstructural characterizations of brick-lime mortars. → Hydraulic character of mortars in Roman baths complex. → Reaction rims were observed around brick fragments and dolomitic grains. → Higher content of brick particles yielded a higher BET surface area. → Addition of brick particles increased porosity and diminished pore size diameter.

  6. Analysis of main parameters affecting substrate/mortar contact area through tridimensional laser scanner.

    Science.gov (United States)

    Stolz, Carina M; Masuero, Angela B

    2015-10-01

    This study assesses the influence of the granulometric composition of sand, application energy and the superficial tension of substrates on the contact area of rendering mortars. Three substrates with distinct wetting behaviors were selected and mortars were prepared with different sand compositions. Characterization tests were performed on fresh and hardened mortars, as well as the rheological characterization. Mortars were applied to substrates with two different energies. The interfacial area was then digitized with 3D scanner. Results show that variables are all of influence on the interfacial contact in the development area. Furthermore, 3D laser scanning proved to be a good method to contact area measurement. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. DOMAIN DECOMPOSITION FOR POROELASTICITY AND ELASTICITY WITH DG JUMPS AND MORTARS

    KAUST Repository

    GIRAULT, V.; PENCHEVA, G.; WHEELER, M. F.; WILDEY, T.

    2011-01-01

    by introducing DG jumps and mortars. The unknowns are condensed on the interface, so that at each time step, the computation in each subdomain can be performed in parallel. In addition, by extrapolating the displacement, we present an algorithm where

  8. Study of the fracture behavior of mortar and concretes with crushed rock or pebble aggregates

    Directory of Open Access Journals (Sweden)

    Sebastião Ribeiro

    2011-03-01

    Full Text Available The objective of this work was to compare the fracture energy of mortar and concretes produced with crushed rock and pebble aggregates using zero, 10, 20, 30 and 40% of aggregates mixed with standard mortar and applying the wedge splitting method to achieve stable crack propagation. The samples were cast in a special mold and cured for 28 days, after which they were subjected to crack propagation tests by the wedge splitting method to determine the fracture energies of the mortar and concrete. The concretes showed higher fracture energy than the mortar, and the concretes containing crushed rock showed higher resistance to crack propagation than all the compositions containing pebbles. The fracture energy varied from 38 to 55 J.m-2. A comparison of the number of aggregates that separated from the two concrete matrices with the highest fracture energies indicated that the concrete containing pebbles crumbled more easily and was therefore less resistant to crack propagation.

  9. SYSTEM OF CONTROL AND MANAGEMENT OF THE PROCESS OF THE MORTAR SLURRY PREPARATION

    Directory of Open Access Journals (Sweden)

    D. M. Kukuj

    2007-01-01

    Full Text Available The technological schema of automatic flow line allowing to prepare with minimum charges of manual labor the refined from solid additives mortar slurry with stable density is presented in the article.

  10. A case study and mechanism investigation of typical mortars used on ancient architecture in China

    International Nuclear Information System (INIS)

    Zeng Yuyao; Zhang Bingjian; Liang Xiaolin

    2008-01-01

    Mortars sampled from Dutifulness Monument, where typical ancient China mortar formulas and manufacturing processes were used, were analyzed by starch-iodine test, FTIR, DSC-TG, SEM and XRD methods. Several modeling samples were then made according to historical records of Chinese ancient mortar formulas and analyzed with the same techniques. The modeling formulas also were used to consolidate loose specimens. The results show that sticky rice plays a crucial role in the microstructure and the consolidation properties of lime mortars. A possible mechanism was suggested that biomineralization may occur during the carbonation of calcium hydroxide, where the sticky rice functions as a template and controls the growth of calcium carbonate crystal. The organic-inorganic materials formed based on this mechanism will be more favorable for consolidating the loose samples both in strength improvement and durability

  11. Valorisation of waste plastic bags in cement-mortar composites as ...

    African Journals Online (AJOL)

    2015-01-07

    Jan 7, 2015 ... Keywords: Waste plastic bags, cement-plastic-mortar composite, aggregates coating ..... and closely attached to the aggregate by physical bonds and ... transformation steps, known as fusing material behaviour. In fact,.

  12. Comparison of setting time and temperature hydration in mortar with substituent ceramic

    International Nuclear Information System (INIS)

    Rodrigues, R.A.; Alves, L.S.; Evangelista, A.C.J.; Almeida, V.C.

    2011-01-01

    The workability of mortar is determined mainly by the kinetics of hydration of the hydraulic binder, the process of gelation / hydration of this material in aqueous solutions is significantly influenced by the presence of additives. As a result, this work aims at studying changes in setting time and temperature of hydration of mortars with 10, 15 and 30% of Portland cement replaced by residues of porcelain and ceramic bricks. The influence of these residues in the cement hydration process was studied by testing takes time, temperature, hydration and X-ray diffraction. The results indicate that the mortar setting time not changed significantly since the temperature of hydration has a minor variation on what is preferred because it reduces the microcracks created in mortar during drying.(author)

  13. Synthesis of Expansive Mortar Developed in Laboratory for Dismounting of Ornamental Rocks

    International Nuclear Information System (INIS)

    Lucena D V; Campos D B C; Lira H L; Neves G A

    2011-01-01

    The expansive mortar is constituted by a mixture of watery phase with an agent expander, when hydrated, presents volume increase and the generation of fictions in the rock due to generated pressure. The objective of this work is to synthecize expansive mortar that they present enough expansive pressure for the dismounting of granite and marble. They had been used as raw materials: carbonate of calcium, Portland cement and additives for control of the expansion. The formularizations had been synthecized on the basis of the chemical analysis of a mortar commercial and characterized by XRD, laser particle size measurements and evaluation of expansive pressure. All the developed formularizations had presented similar characteristics to the ones of the commercial mortar.

  14. Effect of water curing duration on strength behaviour of portland composite cement (PCC) mortar

    Science.gov (United States)

    Caronge, M. A.; Tjaronge, M. W.; Hamada, H.; Irmawaty, R.

    2017-11-01

    Cement manufacturing of Indonesia has been introduced Portland Composite Cement (PCC) to minimize the rising production cost of cement which contains 80% clinker and 20% mineral admixture. A proper curing is very important when the cement contains mineral admixture materials. This paper reports the results of an experimental study conducted to evaluate the effect of water curing duration on strength behaviour of PCC mortar. Mortar specimens with water to cement ratio of (W/C) 0.5 were casted. Compressive strength, flexural strength and concrete resistance were tested at 7, 28 and 91 days cured water. The results indicated that water curing duration is essential to continue the pozzolanic reaction in mortar which contributes to the development of strength of mortar made with PCC.

  15. Field and laboratory determination of a poly(vinyl/vinylidene chloride) additive in brick mortar.

    Science.gov (United States)

    Law, S L; Newman, J H; Ptak, F L

    1990-02-01

    A polymerized vinyl/vinylidene chloride additive, used in brick mortar during the 60s and 70s, is detected at the building site by the field method, which employs a commercially available chloride test strip. The field test results can then be verified by the laboratory methods. In one method, total chlorine in the mortar is determined by an oxygen-bomb method and the additive chloride is determined by difference after water-soluble chlorides have been determined on a separate sample. In the second method, the polymerized additive is extracted directly from the mortar with tetrahydrofuran (THF). The difference in weight before and after extraction of the additive gives the weight of additive in the mortar. Evaporation of the THF from the extract leaves a thin film of the polymer, which gives an infrared "fingerprint" spectrum characteristic of the additive polymer.

  16. Recycled Glass Fiber Reinforced Polymer Composites Incorporated in Mortar for Improved Mechanical Performance

    Science.gov (United States)

    2017-12-11

    Glass fiber reinforced polymer (GFRP) recycled from retired wind turbines was implemented in mortar as a volumetric replacement of sand during the two phases of this study. In Phase I, the mechanically refined GFRP particle sizes were sieved for four...

  17. Role of cellular adhesions in tissue dynamics spectroscopy

    Science.gov (United States)

    Merrill, Daniel A.; An, Ran; Turek, John; Nolte, David

    2014-02-01

    Cellular adhesions play a critical role in cell behavior, and modified expression of cellular adhesion compounds has been linked to various cancers. We tested the role of cellular adhesions in drug response by studying three cellular culture models: three-dimensional tumor spheroids with well-developed cellular adhesions and extracellular matrix (ECM), dense three-dimensional cell pellets with moderate numbers of adhesions, and dilute three-dimensional cell suspensions in agarose having few adhesions. Our technique for measuring the drug response for the spheroids and cell pellets was biodynamic imaging (BDI), and for the suspensions was quasi-elastic light scattering (QELS). We tested several cytoskeletal chemotherapeutic drugs (nocodazole, cytochalasin-D, paclitaxel, and colchicine) on three cancer cell lines chosen from human colorectal adenocarcinoma (HT-29), human pancreatic carcinoma (MIA PaCa-2), and rat osteosarcoma (UMR-106) to exhibit differences in adhesion strength. Comparing tumor spheroid behavior to that of cell suspensions showed shifts in the spectral motion of the cancer tissues that match predictions based on different degrees of cell-cell contacts. The HT-29 cell line, which has the strongest adhesions in the spheroid model, exhibits anomalous behavior in some cases. These results highlight the importance of using three-dimensional tissue models in drug screening with cellular adhesions being a contributory factor in phenotypic differences between the drug responses of tissue and cells.

  18. Optical adhesive property study

    Energy Technology Data Exchange (ETDEWEB)

    Sundvold, P.D.

    1996-01-01

    Tests were performed to characterize the mechanical and thermal properties of selected optical adhesives to identify the most likely candidate which could survive the operating environment of the Direct Optical Initiation (DOI) program. The DOI system consists of a high power laser and an optical module used to split the beam into a number of channels to initiate the system. The DOI requirements are for a high shock environment which current military optical systems do not operate. Five candidate adhesives were selected and evaluated using standardized test methods to determine the adhesives` physical properties. EC2216, manufactured by 3M, was selected as the baseline candidate adhesive based on the test results of the physical properties.

  19. Influence of cellulose ether particle size on water retention of freshly-mixed mortars

    OpenAIRE

    Patural , Laetitia; Govin , Alexandre; Grosseau , Philippe; Ruot , Bertrand; Deves , Olivier

    2009-01-01

    International audience; Cellulose ethers are polymers frequently introduced into mortar formulations in order to improve water retention capacity and workability of the freshly-mixed materials. Physico-chemical parameters of these admixtures (molecular weight, granulometry, substitution degrees, etc) seem to have a strong influence on mortar water retention capacity. In this paper, the influence of cellulose ether particle size was studied. Two behaviors were highlighted regarding the particl...

  20. Global consolidation of industries and business failures: insights from brick-and-mortar and online outlets

    OpenAIRE

    Amankwah-Amoah, Joseph

    2017-01-01

    Although online platforms are increasingly seen as a linchpin for firms competing in the 21st century, our understanding of competition between the traditional brick-and-mortar and online outlets, and how this can lead to different types of business failures, remains limited. In the light of the disjointed nature of the current streams of research, we propose an integrated framework that classifies the differential effects of online and brick-and-mortar competition. Based on a review of the l...

  1. Hydromechanical properties of some mortars used in some ecologic construction techniques

    OpenAIRE

    Hoxha , Dashnor; Vladimir Nicolae , Ungureanu; Belayachi , Naima; Duc Phi , Do

    2012-01-01

    International audience; This paper presents results of hydromechanical characterization tests performed on some mortars used in eco-construction practice. Typically, such mortars could be found in buildings constructed following so called GREB technique that uses straw bales as structural and insulating elements in addition to a wood frame. The full experimental program includes thermal, mechanical and hydraulic - hygroscopic tests. Mechanical tests, including uniaxial compression test and th...

  2. Bioinspired pressure actuated adhesive system

    NARCIS (Netherlands)

    Paretkar, D.R.; Kamperman, M.M.G.; Schneider, A.S.; Martina, D.; Creton, C.; Arzt, E.

    2011-01-01

    We developed a dry synthetic adhesive system inspired by gecko feet adhesion that can switch reversibly from adhesion to non-adhesion with applied pressure as external stimulus. Micropatterned polydimethylsiloxane (PDMS) surfaces with pillars of 30 µm length and 10 µm diameter were fabricated using

  3. Many Roles of Wood Adhesives

    Science.gov (United States)

    Charles R. Frihart

    2014-01-01

    Although wood bonding is one of the oldest applications of adhesives, going back to early recorded history (1), some aspects of wood bonds are still not fully understood. Most books in the general area of adhesives and adhesion do not cover wood bonding. However, a clearer understanding of wood bonding and wood adhesives can lead to improved products. This is important...

  4. Cohesion and Adhesion with Proteins

    Science.gov (United States)

    Charles R. Frihart

    2016-01-01

    With increasing interest in bio-based adhesives, research on proteins has expanded because historically they have been used by both nature and humans as adhesives. A wide variety of proteins have been used as wood adhesives. Ancient Egyptians most likely used collagens tobond veneer to wood furniture, then came casein (milk), blood, fish scales, and soy adhesives, with...

  5. 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.

  6. FREEZE-THAW AND FIRE RESISTANCE OF GEOPOLYMER MORTAR BASED ON NATURAL AND WASTE POZZOLANS

    Directory of Open Access Journals (Sweden)

    F.Nurhayat Degirmenci

    2017-12-01

    Full Text Available The purpose of this research was to investigate the resistance of pozzolan-based geopolymer mortars subjected to high temperatures and freeze-thaw cycles. Low calcium fly ash and granulated blast furnace slag as waste pozzolans and natural zeolite as a natural pozzolan were used as base materials for producing geopolymer mortar. The other purpose the research was to study the effect of alkaline activator ratio (Na₂SiO₃/NaOH on the performance of pozzolan-based geopolymer mortar specimens subjected to extreme temperatures. The influence of high temperatures on the properties of mortars was investigated at 300°C, 600°C, and 900°C. Fire and freeze-thaw and resistance of mortars were investigated in terms of visual appearance, weight loss and residual compressive strength. The minimal values of the residual compressive strength were obtained at 900°C for all mixtures. The residual compressive strength of all specimens was lower than the values obtained for specimens not subjected to any freeze-thaw resistance test, except those containing GGBS. The Na₂SiO₃/NaOH ratios of the alkaline activator solution used to prepare the geopolymer mortars have an effect on the weight losses and residual compressive strengths of the specimens subjected to high temperatures and freeze-thaw cycles. As the Na2SiO3/NaOH ratios increased, the weight and strength losses decreased.

  7. Effect of nylon fiber on mechanical properties of cement based mortar

    Science.gov (United States)

    Hanif, I. M.; Syuhaili, M. R. Noor; Hasmori, M. F.; Shahmi, S. M.

    2017-11-01

    An investigation has been carried out to study the effect of nylon fiber on the mechanical properties of cement based mortar after receiving large quantities of nylon waste. Subsequently, this research was conducted to compare the compressive, tensile and flexural strength of normal cement based mortar with nylon fiber cement based mortar. All samples using constant water-cement ratio of 0.63 and three different percentages of nylon fiber were added in the mixture during the samples preparation period which consists of 0.5%, 1.5% and 2.5% by total weight of cement based mortar. The results obtained with different nylon percentage marked an increases in compressive strength (up to 17%), tensile strength (up to 21%) and flexural strength (up to 13%) when compared with control cement based mortar samples. Therefore, the results obtained from this study shows that by using nylon fiber as additive material can improve the mechanical properties of the cement based mortar and at the same time produce a good sustainable product that can protects and conserve the marine environment.

  8. Study on compressive strength of self compacting mortar cubes under normal & electric oven curing methods

    Science.gov (United States)

    Prasanna Venkatesh, G. J.; Vivek, S. S.; Dhinakaran, G.

    2017-07-01

    In the majority of civil engineering applications, the basic building blocks were the masonry units. Those masonry units were developed as a monolithic structure by plastering process with the help of binding agents namely mud, lime, cement and their combinations. In recent advancements, the mortar study plays an important role in crack repairs, structural rehabilitation, retrofitting, pointing and plastering operations. The rheology of mortar includes flowable, passing and filling properties which were analogous with the behaviour of self compacting concrete. In self compacting (SC) mortar cubes, the cement was replaced by mineral admixtures namely silica fume (SF) from 5% to 20% (with an increment of 5%), metakaolin (MK) from 10% to 30% (with an increment of 10%) and ground granulated blast furnace slag (GGBS) from 25% to 75% (with an increment of 25%). The ratio between cement and fine aggregate was kept constant as 1: 2 for all normal and self compacting mortar mixes. The accelerated curing namely electric oven curing with the differential temperature of 128°C for the period of 4 hours was adopted. It was found that the compressive strength obtained from the normal and electric oven method of curing was higher for self compacting mortar cubes than normal mortar cube. The cement replacement by 15% SF, 20% MK and 25%GGBS obtained higher strength under both curing conditions.

  9. Repair Mortars and New Concretes with Coal Bottom and Biomass Ashes Using Rheological Optimisation

    International Nuclear Information System (INIS)

    Bras, A.; Faustino, P.

    2016-01-01

    The objective of the present work is to analyse the potential of using non-classical additions in concrete and mortar compositions such as coal bottom ash and biomass ash (Bio), as partial replacing binder of ordinary Portland cement. It is intended to deal with production of these type of wastes and its accumulation and contribute to the minimisation of carbon and embodied energy in construction materials. The aim is to identify the concrete and mortars formulation types where it is possible to get more benefit by incorporating bottom ash and Bio. Based on the optimisation of the rheological properties of cement-based materials, mortars with repair function and concrete compositions were developed including 0%, 10%, 15% and 20% of bottom ash and Bio as cement replacement. An assessment of the evolution of relative concrete compressive strength was calculated as a function of the relative solid volume fraction of several concretes. bottom ash compositions present low resistance to high flow rates, increasing the ease of placement and vibration. bottom ash seems to present more filler and pozzolanic effect when compared with Bio. bottom ash mortars fulfil the compressive strength and stiffness requirements to be used as repair mortars, allowing the replacement of 15% or 20% of cement by an industrial waste. This by-product is able to work in the development of the mortar and concrete microstructure strength adopting a much more sustainable solution for the environment.

  10. Effects of Shrinkage Reducing Agent and Expansive Additive on Mortar Properties

    Directory of Open Access Journals (Sweden)

    Sarapon Treesuwan

    2017-01-01

    Full Text Available This research is to study the effect of mortar mixed with shrinkage reducing agent (polyoxyalkylene alkyl ether type, expansive additive (CaO type, and fly ash (hereinafter “SRA,” “EX,” and “FA,” resp.. Moreover, steam curing was studied to improve the properties of mortar. The plastic shrinkage test was conducted by using the strain gauge embedded at 0.5 cm from the surface according to the ASTM C1579-06 standard within early age followed by the total shrinkage test and compressive strength test. The test results showed that mixing both the EX and SRA increases the plastic enlargement of the mortar during the early age more than using either the EX or SRA solely. The steam curing helps to reduce the plastic shrinkage when the mortar is added with the FA and SRA while adding the EX increases the enlargement compared to the normal curing. When the EX, SRA, and FA are all added to the mortar mixing, great attention should be paid due to the increase of greater enlargement. For the compressive strength view, the steam curing increases the compressive strength in all types of mixture. The steam curing significantly helps increasing the compressive strength of mortar with combination of EX, SRA, and FA. Nevertheless, the XRD and SEM tests explain such enlargement accordingly.

  11. Mineralogical and textural characterization of mortars and plasters from the archaeological site of Barsinia, northern Jordan

    Directory of Open Access Journals (Sweden)

    Mustafa Mohammad AL-Naddaf

    2014-12-01

    Full Text Available Twelve mortar and plaster samples excavated in the archaeological site of Barsinia were mineralogically and petrographically examined by XRay Diffraction (XRD and Stereo and Polarized Light Microscopy, while the total carbonate content was measured using a DietrichFruhling Calcimeter. The physical properties of the samples, such as water uptake under atmospheric pressure and under vacuum, together with density and porosity, were measured. Only twelve samples were available for the purposes of this study: 8 plaster samples and 4 mortar samples. Eleven samples out of the total number of samples were mortars or plasters with lime binder and silica aggregate; calcite and quartz were identified in all of these samples. In most of the samples one or more pozzolanic components were detected; a hydraulic effect therefore exists in practically most of the studied mortars. Excluding the plasters taken from waterbearing constructions such as cisterns, and the mortar sample from the compact floor, the binder content is high; in general, the overall porosity of the studied samples is high. Porosity and petrographic investigation results suggest that the burning temperature of the limestone was low and/or the duration of the combustion was short; such preparation conditions produce a desirable quicklime. Owing to the significant compositional and textural differences between the samples that were reported, there is consequently no suitable general mortar that can be adopted for the restoration of the whole site.

  12. The influence of untreated sugarcane bagasse ash on the microstructural and mechanical properties of mortars

    International Nuclear Information System (INIS)

    Maldonado-García, M.A.; Hernández-Toledo, U.I.; Montes-García, P.; Valdez-Tamez, P.L.

    2018-01-01

    This study investigated the effects of the addition of untreated sugarcane bagasse ash (UtSCBA) on the microstructural and mechanical properties of mortars. The SCBA was sieved for only five minutes through a No. 200 ASTM mesh, and fully characterized by chemical composition analysis, laser ray diffraction, the physical absorption of gas, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Mortar mixtures with 0, 10 and 20% UtSCBA as cement replacement and a constant 0.63 water/cementitious material ratio were prepared. Fresh properties of the mortars were obtained. The microstructural characteristics of the mortars at 1, 7, 28, 90 and 600 days were evaluated by SEM and XRD. The compressive strengths of the mortars at the same ages were then obtained. The results show that the addition of 10 and 20% UtSCBA caused a slight decrease in workability of the mortars but improved their microstructure, increasing the long-term compressive strength. [es

  13. Chloride Ion Adsorption Capacity of Anion Exchange Resin in Cement Mortar

    Directory of Open Access Journals (Sweden)

    Yunsu Lee

    2018-04-01

    Full Text Available This paper presents the effect of anion exchange resin (AER on the adsorption of chloride ions in cement mortar. The kinetic and equilibrium behaviors of AER were investigated in distilled water and Ca(OH2 saturated solutions, and then the adsorption of chloride ions by the AER in the mortar specimen was determined. The AER was used as a partial replacement for sand in the mortar specimen. The mortar specimen was coated with epoxy, except for an exposed surface, and then immersed in a NaCl solution for 140 days. The chloride content in the mortar specimen was characterized by energy dispersive X-ray fluorescence analysis and electron probe microanalysis. The results showed that the AER could adsorb the chloride ions from the solution rapidly but had a relatively low performance when the pH of its surrounding environment increased. When the AER was mixed in the cement mortar, its chloride content was higher than that of the cement matrix around it, which confirms the chloride ion adsorption capacity of the AER.

  14. Effects of replacement of binder content on bond strength of mortars

    Directory of Open Access Journals (Sweden)

    E. B. C. Costa

    Full Text Available The reduction of binder content in cementitious systems is an effective way to mitigate environmental impacts without increasing costs. The main purpose of this study is to evaluate the effect of content binder on bond strength of mortar-brick interface. For thus, it was studied mortars produced with two limestone fines with different particle size distribution. The limestone fines were added at rates of 0% to 60% at increments of 15% as partial volume replacement of binder. Mortars were prepared in proportion of 1:3 (binder + limestone: sand in volume. The water content was kept constant and equal to 18% in relation to total weight of solids. The mechanical property of mortars was evaluated by tensile strength and the performance of interface by bond strength tests at 14 days. Results indicate that is possible make mortars with 45% less than binder without reducing bond strength. Thus, the use of appropriate particles of limestone can produce more environmentally friendly concrete and rendering mortars by reducing its binder factor without affecting its performance.

  15. Experimental Investigation of Multi-mode Fiber Laser Cutting of Cement Mortar

    Science.gov (United States)

    2018-01-01

    This study successfully applied multi-mode laser cutting with the variation of the laser cutting speed to cement mortar for the first time. The effects of the amount of silica sand in the cement mortar on laser cutting are tested and analyzed. The kerf width and penetration depth of the specimens after laser cutting are investigated. As the laser cutting speed increases, the penetration depth decreases for both cement paste and cement mortar, whereas the kerf width becomes saturated and increases, respectively, for cement paste and cement mortar. Cross sections of the specimens are compared with illustrations. Top-view images of the cement mortar with indicators of the physical characteristics, such as re-solidification, burning, and cracks are examined, and the possible causes of these characteristics are explained. The optical absorption rates of cement-based materials are quantified at wide ranges of wavelength to compare the absorption rates in accordance with the materials compositions. The chemical composition variation before and after laser cutting is also compared by EDX (Energy Dispersive X-Ray) analysis. In addition to these observations, material removal mechanisms for cement mortar are proposed. PMID:29439431

  16. Compressive and flexural strength of expanded perlite aggregate mortar subjected to high temperatures

    Science.gov (United States)

    Zulkifeli, Muhamad Faqrul Hisham bin Mohd; Saman@Hj Mohamed, Hamidah binti Mohd

    2017-08-01

    Work on thermal resistant of outer structures of buildings is one of the solution to reduce death, damages and properties loss in fire cases. Structures protected with thermal resistant materials can delay or avoid failure and collapse during fire. Hence, establishment of skin cladding with advance materials to protect the structure of buildings is a necessary action. Expanded perlite is a good insulation material which can be used as aggregate replacement in mortar. This study is to study on mortar mechanical properties of flexural and compressive strength subjected to elevated temperatures using expanded perlite aggregate (EPA). This study involved experimental work which was developing mortar with sand replacement by volume of 0%, 10%, 20%, 30% and 40% of EPA and cured for 56 days. The mortars then exposed to 200°C, 400 °C, 700 °C and 1000 °C. Flexural and compressive strength of the mortar were tested. The tests showed that there were increased of flexural and compressive strength at 200°C, and constantly decreased when subjected to 400°C, 700°C and 1000 °C. There were also variation of strengths at different percentages of EPA replacement. Highest compressive strength and flexural strength recorded were both at 200 °C with 65.52 MPa and 21.34 MPa respectively. The study conclude that by using EPA as aggregate replacement was ineffective below elevated temperatures but increased the performance of the mortar at elevated temperatures.

  17. Experimental Investigation of Multi-mode Fiber Laser Cutting of Cement Mortar.

    Science.gov (United States)

    Lee, Dongkyoung; Pyo, Sukhoon

    2018-02-10

    This study successfully applied multi-mode laser cutting with the variation of the laser cutting speed to cement mortar for the first time. The effects of the amount of silica sand in the cement mortar on laser cutting are tested and analyzed. The kerf width and penetration depth of the specimens after laser cutting are investigated. As the laser cutting speed increases, the penetration depth decreases for both cement paste and cement mortar, whereas the kerf width becomes saturated and increases, respectively, for cement paste and cement mortar. Cross sections of the specimens are compared with illustrations. Top-view images of the cement mortar with indicators of the physical characteristics, such as re-solidification, burning, and cracks are examined, and the possible causes of these characteristics are explained. The optical absorption rates of cement-based materials are quantified at wide ranges of wavelength to compare the absorption rates in accordance with the materials compositions. The chemical composition variation before and after laser cutting is also compared by EDX (Energy Dispersive X-Ray) analysis. In addition to these observations, material removal mechanisms for cement mortar are proposed.

  18. Adhesives for orthodontic bracket bonding

    Directory of Open Access Journals (Sweden)

    Déborah Daniella Diniz Fonseca

    2010-04-01

    Full Text Available The advent of acid etching, introduced by Buonocore in 1955, brought the possibility of bonding between the bracket base and enamel, contributing to more esthetic and conservative orthodontics. This direct bracket bonding technique has brought benefits such as reduced cost and time in performing the treatment, as well as making it easier to perform oral hygiene. The aim of this study was to conduct a survey of published studies on orthodontic bracket bonding to dental enamel. It was verified that resin composites and glass ionomer are the most studied and researched materials for this purpose. Resin-modified glass ionomer, with its biocompatibility, capacity of releasing fluoride and no need for acid etching on the tooth structure, has become increasingly popular among dentists. However, due to the esthetic and mechanical properties of light polymerizable resin composite, it continues to be one of the adhesives of choice in the bracket bonding technique and its use is widely disseminated.

  19. Dry adhesives with sensing features

    International Nuclear Information System (INIS)

    Krahn, J; Menon, C

    2013-01-01

    Geckos are capable of detecting detachment of their feet. Inspired by this basic observation, a novel functional dry adhesive is proposed, which can be used to measure the instantaneous forces and torques acting on an adhesive pad. Such a novel sensing dry adhesive could potentially be used by climbing robots to quickly realize and respond appropriately to catastrophic detachment conditions. The proposed torque and force sensing dry adhesive was fabricated by mixing Carbon Black (CB) and Polydimethylsiloxane (PDMS) to form a functionalized adhesive with mushroom caps. The addition of CB to PDMS resulted in conductive PDMS which, when under compression, tension or torque, resulted in a change in the resistance across the adhesive patch terminals. The proposed design of the functionalized dry adhesive enables distinguishing an applied torque from a compressive force in a single adhesive pad. A model based on beam theory was used to predict the change in resistance across the terminals as either a torque or compressive force was applied to the adhesive patch. Under a compressive force, the sensing dry adhesive was capable of measuring compression stresses from 0.11 Pa to 20.9 kPa. The torque measured by the adhesive patch ranged from 2.6 to 10 mN m, at which point the dry adhesives became detached. The adhesive strength was 1.75 kPa under an applied preload of 1.65 kPa for an adhesive patch with an adhesive contact area of 7.07 cm 2 . (paper)

  20. Dry adhesives with sensing features

    Science.gov (United States)

    Krahn, J.; Menon, C.

    2013-08-01

    Geckos are capable of detecting detachment of their feet. Inspired by this basic observation, a novel functional dry adhesive is proposed, which can be used to measure the instantaneous forces and torques acting on an adhesive pad. Such a novel sensing dry adhesive could potentially be used by climbing robots to quickly realize and respond appropriately to catastrophic detachment conditions. The proposed torque and force sensing dry adhesive was fabricated by mixing Carbon Black (CB) and Polydimethylsiloxane (PDMS) to form a functionalized adhesive with mushroom caps. The addition of CB to PDMS resulted in conductive PDMS which, when under compression, tension or torque, resulted in a change in the resistance across the adhesive patch terminals. The proposed design of the functionalized dry adhesive enables distinguishing an applied torque from a compressive force in a single adhesive pad. A model based on beam theory was used to predict the change in resistance across the terminals as either a torque or compressive force was applied to the adhesive patch. Under a compressive force, the sensing dry adhesive was capable of measuring compression stresses from 0.11 Pa to 20.9 kPa. The torque measured by the adhesive patch ranged from 2.6 to 10 mN m, at which point the dry adhesives became detached. The adhesive strength was 1.75 kPa under an applied preload of 1.65 kPa for an adhesive patch with an adhesive contact area of 7.07 cm2.

  1. Modification of in natura starch for application in adhesives

    International Nuclear Information System (INIS)

    Lopes, Gisela K.; Andrade, Cristina T.

    2001-01-01

    Commercial modified starches used in adhesive formulations have been characterized by infrared, spectroscopy, 13 C-NMR and viscosimetry. Several reactions have been carried out with starch in natura in acid solutions and the resulting products have been compared with the commercial samples. The product obtained by acid hydrolysis at 60 deg C for 90 min was characterized as the most appropriate to be used in adhesive formulations. (author)

  2. Lime mortar with mixed in crystallization modifiers to mitigate salt damage

    NARCIS (Netherlands)

    Granneman, S.J.C.; Lubelli, B.; Hees, R.P.J. van

    2016-01-01

    Although salt crystallization damage is a widespread damage process in the porous materials of our built cultural heritage, no definite solution yet exists to improve the durability of materials with respect to salt crystallization. Most research focuses on improving material properties, whereas

  3. Microstructural Properties of Cement Paste and Mortar Modified by Low Cost Nanoplatelets Sourced from Natural Materials

    Directory of Open Access Journals (Sweden)

    Piao Huang

    2018-05-01

    Full Text Available Nanomaterials have been widely used in cement-based materials. Graphene has excellent properties for improving the durability of cement-based materials. Given its high production budget, it has limited its wide potential for application in the field of engineering. Hence, it is very meaningful to obtain low cost nanoplatelets from natural materials that can replace graphene nanoplatelets (GNPs The purpose of this paper is to improve the resistance to chloride ion penetration by optimizing the pore structure of cement-based materials, and another point is to reduce investment costs. The results illustrated that low cost CaCO3 nanoplatelets (CCNPs were successfully obtained under alkali treatment of seashell powder, and the chloride ion permeability of cement-based materials significantly decreased by 15.7% compared to that of the control samples when CCNPs were incorporated. Furthermore, the compressive strength of cement pastes at the age of 28 days increased by 37.9% than that of the plain sample. Improvement of performance of cement-based materials can be partly attributed to the refinement of the pore structure. In addition, AFM was employed to characterize the nanoplatelet thickness of CCNPs and the pore structures of the cement-based composites were analyzed by MIP, respectively. CCNPs composite cement best performance could lay the foundation for further study of the durability of cement-based materials and the application of decontaminated seashells.

  4. Adhesives for fixed orthodontic brackets.

    Science.gov (United States)

    Mandall, Nicky A; Hickman, Joy; Macfarlane, Tatiana V; Mattick, Rye Cr; Millett, Declan T; Worthington, Helen V

    2018-04-09

    duplicate by pairs of review authors. Since the data were not presented in a form that was amenable to meta-analysis, the results of the review are presented in narrative form only. Three trials satisfied the inclusion criteria. A chemical cured composite was compared with a light cured composite (one trial), a conventional glass ionomer cement (one trial) and a polyacid-modified resin composite (compomer) (one trial). The quality of the trial reports was generally poor. There is no clear evidence on which to make a clinical decision of the type of orthodontic adhesive to use.

  5. 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

  6. Influence of light-weight masonry mortar on the thermal insulation of walling made from hollow blocks

    Energy Technology Data Exchange (ETDEWEB)

    Kupke, C; Schuele, M

    1984-10-01

    The thermal conductivity equivalent of hollow-block masonry with different types of mortar is calculated for ten different types of blocks as a function of the thermal conductivity of the brick material. A measure is derived for determining the improved thermal conductivity of hollow-block masonry with light mortar as compared to walls with normal mortar. The findings supplement the findings already obtained for solid bricks.

  7. Parallel 3D Mortar Element Method for Adaptive Nonconforming Meshes

    Science.gov (United States)

    Feng, Huiyu; Mavriplis, Catherine; VanderWijngaart, Rob; Biswas, Rupak

    2004-01-01

    High order methods are frequently used in computational simulation for their high accuracy. An efficient way to avoid unnecessary computation in smooth regions of the solution is to use adaptive meshes which employ fine grids only in areas where they are needed. Nonconforming spectral elements allow the grid to be flexibly adjusted to satisfy the computational accuracy requirements. The method is suitable for computational simulations of unsteady problems with very disparate length scales or unsteady moving features, such as heat transfer, fluid dynamics or flame combustion. In this work, we select the Mark Element Method (MEM) to handle the non-conforming interfaces between elements. A new technique is introduced to efficiently implement MEM in 3-D nonconforming meshes. By introducing an "intermediate mortar", the proposed method decomposes the projection between 3-D elements and mortars into two steps. In each step, projection matrices derived in 2-D are used. The two-step method avoids explicitly forming/deriving large projection matrices for 3-D meshes, and also helps to simplify the implementation. This new technique can be used for both h- and p-type adaptation. This method is applied to an unsteady 3-D moving heat source problem. With our new MEM implementation, mesh adaptation is able to efficiently refine the grid near the heat source and coarsen the grid once the heat source passes. The savings in computational work resulting from the dynamic mesh adaptation is demonstrated by the reduction of the the number of elements used and CPU time spent. MEM and mesh adaptation, respectively, bring irregularity and dynamics to the computer memory access pattern. Hence, they provide a good way to gauge the performance of computer systems when running scientific applications whose memory access patterns are irregular and unpredictable. We select a 3-D moving heat source problem as the Unstructured Adaptive (UA) grid benchmark, a new component of the NAS Parallel

  8. Incorporation mode effect of Nano-silica on the rheological and mechanical properties of cementitious pastes and cement mortars

    Science.gov (United States)

    Safi, B.; Aknouche, H.; Mechakra, H.; Aboutaleb, D.; Bouali, K.

    2018-04-01

    Previous research indicates that the inclusion of nanosilica (NS) modifies the properties of the fresh and hardened state, compared to the traditional mineral additions. NS decreases the setting times of the cement mortar compared to silica fume (SF) and reduce of required water while improving the cohesion of the mixtures in the fresh state. Some authors estimate that the appropriate percentage of Nano-silica should be small (1 to 5% by weight) because of difficulties caused by agglomeration to particles during mixing, while others indicate that 10% by weight, if adjustments are made to the formulation to avoid an excess of self-drying and micro cracks that could impede strength. For this purpose, the present work aim to see the effect of the introduction mode of the nanosilica on the rheological and physic mechanical properties of cement mortars. In this study, NS was used either powdered with cement or in solution with the superplasticizer (Superplasticizer doped in nanosilica). Results show that the use of nanosilica powder (replacing cement on the one hand) has a negative influence on the rheological parameters and the rheological behavior of cementitious pastes. However, the introduction of nanosilica in solution in the superplasticizer (SP) was significantly improved the rheological parameters and the rheological behavior of cementitious pastes. Indeed, more the dosage of NS-doped SP increases more the shear stress and viscosities of the cementitious pastes become more fluid and manageable. A significant reduction of shear stress and plastic viscosity were observed that due to the increase in superplasticizer. A dosage of 1.5% NS-doped SP gave adequate fluidity and the shear rate was lower.

  9. 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.

  10. Electrically Conductive Epoxy Adhesives

    Directory of Open Access Journals (Sweden)

    Lan Bai

    2011-02-01

    Full Text Available Conductive adhesives are widely used in electronic packaging applications such as die attachment and solderless interconnections, component repair, display interconnections, and heat dissipation. The effects of film thickness as functions of filler volume fraction, conductive filler size, shape, as well as uncured adhesive matrix viscosity on the electrical conduction behavior of epoxy-based adhesives are presented in this work. For this purpose, epoxy-based adhesives were prepared using conductive fillers of different size, shape, and types, including Ni powder, flakes, and filaments, Ag powder, and Cu powder. The filaments were 20 μm in diameter, and 160 or 260 μm in length. HCl and H3PO4 acid solutions were used to etch and remove the surface oxide layers from the fillers. The plane resistance of filled adhesive films was measured using the four-point method. In all cases of conductive filler addition, the planar resistivity levels for the composite adhesive films increased when the film thickness was reduced. The shape of resistivity-thickness curves was negative exponential decaying type and was modeled using a mathematical relation. The relationships between the conductive film resistivities and the filler volume fractions were also derived mathematically based on the experimental data. Thus, the effects of surface treatment of filler particles, the type, size, shape of fillers, and the uncured epoxy viscosity could be included empirically by using these mathematical relations based on the experimental data. By utilizing the relations we proposed to model thickness-dependent and volume fraction-dependent conduction behaviors separately, we were able to describe the combined and coupled volume fraction-film thickness relationship mathematically based on our experimental data.

  11. Influence of bending deflection rate on properties of fibrous mortar

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    Metwally Abd Allah Abd el Aty

    2013-04-01

    Full Text Available Selection of the construction materials is affected by many factors including their properties under the applied loads. Loading rate is considered as a very important parameter which influences the behavior of the materials. Fibrous concrete is commonly used in applications in which the loading rate exceeds quasi static conditions by a large margin. This paper investigates the influence of flexural loading rate on the performance of fibrous concrete prisms in flexure. Two hundred and fifty two prisms include fibrous concrete and control specimens were prepared and tested. Fiber type, fiber dosage and flexural loading rate were the main parameters considered in this study. Two types of fibers were investigated namely polypropylene fibers and glass fibers. Three dosages of fiber volume fractions were implemented as 0.5%, 1.0% and 2.0%. A total of 12 different rates of displacement (0.0039 up to 8 mm/s for load application were conducted. A computer controlled universal testing machine provided with data acquisition system capable of performing 1000 loop per second was used. Load–central deflection, flexural strength and toughness were the evaluated properties for the investigated specimens. The results indicated that the flexure strength values exhibited loading rate dependence not only for the control mix but also for the investigated fibrous mortar mixes. Also the performance in flexure varied substantially not only with loading rate but with fiber type and fiber volume fractions as well.

  12. Mortar cohesión. The effect of additives

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    Castro, J. H.

    1975-12-01

    Full Text Available This study was concerned with the hydration of clinker compounds in the presence of different additives; it appeared that accelerating additives, such as calcium chloride and silicic acid, produce longer fibers of tobermorite, whereas inhibitors, such as sugar, produce shorter fibers of tobermorite. This same effect was observed in the hydration of anhydrite, in which large crystals of gypsum were produced in the presence of sodium sulphate. So the cohesion in mortars of cement and anhydrite is explained in terms of the role of fibers.Se estudia la hidratación del clínker en presencia de diferentes aditivos encontrándose que los aceleradores, como el cloruro cálcico y el ácido salicílico, producen tobermorita de fibra larga y los inhibidores, como el azúcar, tobermorita de fibra corta. Este mismo efecto se encuentra en la anhidrita, produciéndose cristales de yeso largo, en presencia del sulfato de sodio, y cristales cortos en ausencia del catalizador. La cohesión de un mortero depende luego del largo de sus fibras. Así la cohesión de los morteros de cemento y anhidrita se explican en función del rol de la fibra.

  13. Intensified Pozzolanic Reaction on Kaolinite Clay-Based Mortar

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    Yang-Hee Kwon

    2017-05-01

    Full Text Available The objective of this study is to develop and characterize kaolinite clay-based structural mortar. The pozzolanic reaction induced from two mineral additives, i.e., calcium hydroxide and silica fume (SF, and the physical filling effect from SF, were found to be effective on the enhancement of structural properties. Based on several preliminary experiments, 7:3 ratio of kaolinite clay/calcium hydroxide was selected as a basic binder. Then, the amount of SF was chosen as 0%, 7.5%, and 15% of the total binder to consider both the chemical and physical effects. The results showed that compressive strengths of samples with 7.5% and 15% SF are significantly increased by approximately 200% and 350%, respectively, at 28 days compared to the sample without SF. However, based on the results of the sample with 15% SF, it is found that excessive addition of SF causes long-term strength loss, possibly owing to micro cracks. With the careful consideration on this long-term behavior, this suggested new mix design can be further extended to develop sustainable structural materials using natural minerals or waste materials with nonbinding properties.

  14. Scientific studies on decorated mud mortar of Ajanta

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    M. Singh

    2014-01-01

    Full Text Available This study is an attempt to reveal the decorated earthen plaster of Ajanta. The mud plaster of Ajanta caves has been analyzed with the help of physical and analytical tools. The results indicate that high silt (>70% low clay soil may have been mixed purposefully with lime (calcite for the reason to enhance the cementing characteristics. The presence of calcium oxalate was detected from FTIR spectra may have been the resultant product of proteic materials presented in mud plaster. Ferrugineous silicate along with rarer gluconite–celendonite and white zeolites were also perceived from SEM and FTIR spectral analysis. The existence of quartz and sepiolite in mud mortar was also detected from XRD and SEM studies. The vegetal matter might have been added to tailor the construction behavior. The analytical results authenticate the similarity of earthen plaster of Ajanta and alluvion deposits of Waghura River just in front of caves, probably used as raw material in improvement of new material that suits for restoration for optimize performance and compatibility with the existing materials.

  15. Sulfate resistance of fly ash-based geopolymer mortar

    Science.gov (United States)

    Saloma, Iqbal, Maulid Muhammad; Aqil, Ibnu

    2017-09-01

    This paper presents sulfuric acid attack of fly ash-based geopolymer mortar. Precursor used in this study was fly ash, and activator used was NaOH and Na2SiO3. The ratio of activator/precursor, ratio of Na2SiO3/NaOH, and ratio of fine aggregate/precursor is 0.42, 2.00, and 2.00, respectively. The molar concentration of NaOH which was used were 8, 10, 12, 14, and 16 M. This study used cube specimen with 5 cm x 5 cm x 5 cm. The results showed that the higher the molar concentration of NaOH, the lower the weight loss. Maximum percentage of weight loss is 3.54% occured for the specimen with molar concentration of NaOH 8 M. The compressive strength for all specimens decreased due to the longer duration of immersion in sulfuric acid solution. However, this percentage of decreasing for compressive strength will be as lower as increasing the molar concentration of NaOH used. The maximum percentage of decreasing is 35.49% for specimen with NaOH 8 M with 90 days of immersion.

  16. Characteristics of shock propagation in high-strength cement mortar

    Science.gov (United States)

    Wang, Zhanjiang; Li, Xiaolan; Zhang, Ruoqi

    2001-06-01

    Planar impact experiments have been performed on high-strength cement mortar to determine characteristics of shock propagation.The experiments were conducted on a light-gas gun,and permanent-magnet particle velocity gages were used to obtain the sand of 0.5 3.5mm size.A bulk density of 2.31g/cm^3,and a compressive and tensile strength of 82MPa and 7.8MPa,respectively,were determined.Three kinds of experimental techniques were used,including the reverse ballistic configuration.These techniques effectively averaged the measured dynamic compression state over a sensibly large volume of the test sample.The impact velocities were controlled over a range of approximately 80m/s to 0.83km/s.Hugoniot equation of state data were obtained for the material over a pressure range of approximately 0.2 2.0GPa,and its nonlinear constitutive relation were analyzed.The experiment results show that,in higher pressure range provided in the experiment,the shock wave in the material splits into two components of an elastic and a plastic,with the Hugoniot elastic limit 0.4 0.5GPa and the precursor velocity about 4.7km/s,and the material presents a very strong nonlinear dynamic response,and its shock amplitude will greatly decrease in propagation.

  17. Influence of polymer fibers on rheological properties of cement mortars

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    Malaszkiewicz Dorota

    2017-10-01

    Full Text Available The reinforcing effect of fibers in cement composites often results in the improvement of the brittle nature of cementitious materials. But the decrease in the workability of fresh concrete is often the disadvantage of fibers addition. Conventional single-point workability tests cannot characterize workability of concrete in terms of fundamental rheological parameters. To this end, this paper describes an investigation of the influence of synthetic fiber additions (fiber length in the range 12–50 mm and volume fraction in the range 0–4% on the rheological properties of fiber reinforced fresh mortar (FRFM and development of these properties over time. The rheometer Viskomat XL was used in this study. Within the limitations of the instrument and testing procedure it is shown that FRFMs conform to the Bingham model. Natural postglacial sand 0/4 mm was used as a fine aggregate and cement CEMI 42.5 R was used as a binder. Three commercial synthetic fibers were selected for these examinations. Rheological properties were expressed in terms of Bingham model parameters g (yield value and h (plastic viscosity. Based on the test results it was found out that the fiber type and volume fraction affected both the yield stress and plastic viscosity.

  18. Influence of polymer fibers on rheological properties of cement mortars

    Science.gov (United States)

    Malaszkiewicz, Dorota

    2017-10-01

    The reinforcing effect of fibers in cement composites often results in the improvement of the brittle nature of cementitious materials. But the decrease in the workability of fresh concrete is often the disadvantage of fibers addition. Conventional single-point workability tests cannot characterize workability of concrete in terms of fundamental rheological parameters. To this end, this paper describes an investigation of the influence of synthetic fiber additions (fiber length in the range 12-50 mm and volume fraction in the range 0-4%) on the rheological properties of fiber reinforced fresh mortar (FRFM) and development of these properties over time. The rheometer Viskomat XL was used in this study. Within the limitations of the instrument and testing procedure it is shown that FRFMs conform to the Bingham model. Natural postglacial sand 0/4 mm was used as a fine aggregate and cement CEMI 42.5 R was used as a binder. Three commercial synthetic fibers were selected for these examinations. Rheological properties were expressed in terms of Bingham model parameters g (yield value ) and h (plastic viscosity). Based on the test results it was found out that the fiber type and volume fraction affected both the yield stress and plastic viscosity.

  19. The Influence of Biochemical Modification on the Properties of Adhesive Compounds

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    Anna Rudawska

    2016-12-01

    Full Text Available The main objective of this study was to determine the effect of biochemical modification of epoxy adhesive compounds on the mechanical properties of a cured adhesive exposed to various climatic factors. The epoxy adhesive was modified by lyophilized fungal metabolites and prepared by three methods. Additionally, the adhesive compound specimens were seasoned for two months at a temperature of 50 °C and 50% humidity in a climate test chamber, Espec SH 661. The tensile strength tests of the adhesive compounds were performed using a Zwick/Roell Z150 testing machine in compliance with the DIN EN ISO 527-1 standard. The examination of the adhesive specimens was performed using two microscopes: a LEO 912AB transmission electron microscope equipped with Quantax 200 for EDS X-ray spectroscopy and a Zeiss 510 META confocal microscope coupled to an AxioVert 200M. The experiments involved the use of a CT Skyscan 1172 tomograph. The results revealed that some mechanical properties of the modified adhesives were significantly affected by both the method of preparation of the adhesive compound and the content of the modifying agent. In addition, it was found that seasoning of the modified adhesives does not lead to a decrease in some of their mechanical properties.

  20. Reversible adhesion switching of porous fibrillar adhesive pads by humidity.

    Science.gov (United States)

    Xue, Longjian; Kovalev, Alexander; Dening, Kirstin; Eichler-Volf, Anna; Eickmeier, Henning; Haase, Markus; Enke, Dirk; Steinhart, Martin; Gorb, Stanislav N

    2013-01-01

    We report reversible adhesion switching on porous fibrillar polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP) adhesive pads by humidity changes. Adhesion at a relative humidity of 90% was more than nine times higher than at a relative humidity of 2%. On nonporous fibrillar adhesive pads of the same material, adhesion increased only by a factor of ~3.3. The switching performance remained unchanged in at least 10 successive high/low humidity cycles. Main origin of enhanced adhesion at high humidity is the humidity-induced decrease in the elastic modulus of the polar component P2VP rather than capillary force. The presence of spongelike continuous internal pore systems with walls consisting of P2VP significantly leveraged this effect. Fibrillar adhesive pads on which adhesion is switchable by humidity changes may be used for preconcentration of airborne particulates, pollutants, and germs combined with triggered surface cleaning.

  1. Switchable bio-inspired adhesives

    Science.gov (United States)

    Kroner, Elmar

    2015-03-01

    Geckos have astonishing climbing abilities. They can adhere to almost any surface and can run on walls and even stick to ceilings. The extraordinary adhesion performance is caused by a combination of a complex surface pattern on their toes and the biomechanics of its movement. These biological dry adhesives have been intensely investigated during recent years because of the unique combination of adhesive properties. They provide high adhesion, allow for easy detachment, can be removed residue-free, and have self-cleaning properties. Many aspects have been successfully mimicked, leading to artificial, bio-inspired, patterned dry adhesives, and were addressed and in some aspects they even outperform the adhesion capabilities of geckos. However, designing artificial patterned adhesion systems with switchable adhesion remains a big challenge; the gecko's adhesion system is based on a complex hierarchical surface structure and on advanced biomechanics, which are both difficult to mimic. In this paper, two approaches are presented to achieve switchable adhesion. The first approach is based on a patterned polydimethylsiloxane (PDMS) polymer, where adhesion can be switched on and off by applying a low and a high compressive preload. The switch in adhesion is caused by a reversible mechanical instability of the adhesive silicone structures. The second approach is based on a composite material consisting of a Nickel- Titanium (NiTi) shape memory alloy and a patterned adhesive PDMS layer. The NiTi alloy is trained to change its surface topography as a function of temperature, which results in a change of the contact area and of alignment of the adhesive pattern towards a substrate, leading to switchable adhesion. These examples show that the unique properties of bio-inspired adhesives can be greatly improved by new concepts such as mechanical instability or by the use of active materials which react to external stimuli.

  2. Properties of mortars made by uncalcined FGD gypsum-fly ash-ground granulated blast furnace slag composite binder

    International Nuclear Information System (INIS)

    Zhong Shiyun; Ni Kun; Li Jinmei

    2012-01-01

    Highlights: ► The mortar with uncalcined FGD gypsum has suitable workability. ► The strength of mortar with uncalcined FGD gypsum is higher than that of mortar without uncalcined FGD gypsum. ► The dry shrinkage of mortar with uncalcined FGD gypsum is lower than that of mortar without uncalcined FGD gypsum. ► The leaching of sulfate ion of mortar is studied. - Abstract: 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.

  3. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. AMS radiocarbon dating of mortar: The case study of the medieval UNESCO site of Modena

    International Nuclear Information System (INIS)

    Carmine, Lubritto; Caroselli, Marta; Lugli, Stefano; Marzaioli, Fabio; Nonni, Sara; Marchetti Dori, S.; Terrasi, Filippo

    2015-01-01

    The carbon dioxide contributing to binder formation during the set of a lime mortar reflects the atmospheric "1"4C content at the time of construction of a building. For this reason, the "1"4C dating of mortars is used with increasing frequencies in archaeological and architectural research. Mortars, however, may also contain carbonaceous contaminants potentially affecting radiocarbon dating. The Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) of the Second University of Naples (SUN) has recently obtained some promising results in mortar radiocarbon dating thanks to the development of a procedure (i.e. CryoSoniC/Cryo2SoniC) aiming to eliminate exogenous C contamination that may occur in a mortar. The construction history of the UNESCO World Heritage Site of Modena (Italy) is still controversial and represents a challenging case study for the application of absolute dating methodologies for different reasons. From the point of view of "1"4C dating, for example, given the high percentage of carbonate aggregates composing these samples, Modena mortars represent an experimental test particularly indicative of exogenous carbon sources suppression ensuring methodology accuracy. In this paper several AMS Radiocarbon dates were carried out on lime lumps with the aim to: (i) verify procedure accuracy by a comparison of the results obtainable from lime lumps dated after different treatments (i.e. bulk lime lumps vs. CryoSoniC purified lime lumps); (ii) compare different building phases absolute chronology for the medieval UNESCO site of Modena, with that assumed by historical sources in order to assess preliminary the "1"4C dating feasibility for of the site. Historical temporal constraints and mortar clustering, based on petrography, have been applied to define a temporal framework of the analyzed structure. Moreover, a detailed petrographic characterization of mortars was used both as a preliminary tool for the choice of samples and to infer

  5. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives.

    Science.gov (United States)

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-11-04

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structures. In this study, we demonstrate that these adhesives are capable of switching adhesion not only in ambient air conditions but also in vacuum. Our bioinspired patterned adhesive with an area of 1 cm(2) provided an adhesion force of 2.6 N ± 0.2 N in air, which was reduced to 1.9 N ± 0.2 N if measured in vacuum. Detachment was induced by buckling of the structures due to a high compressive preload and occurred, independent of air pressure, at approximately 0.9 N ± 0.1 N. The switch in adhesion was observed at a compressive preload between 5.6 and 6.0 N and was independent of air pressure. The difference between maximum adhesion force and adhesion force after buckling gives a reasonable window of operation for pick and place processes. High reversibility of the switching behavior is shown over 50 cycles in air and in vacuum, making the bioinspired switchable adhesive applicable for handling operations of fragile objects.

  6. Mechanical and radiation shielding properties of mortars with additive fine aggregate mine waste

    International Nuclear Information System (INIS)

    Gallala, Wissem; Hayouni, Yousra; Gaied, Mohamed Essghaier; Fusco, Michael; Alsaied, Jasmin; Bailey, Kathryn; Bourham, Mohamed

    2017-01-01

    Highlights: • Effectiveness of mine waste as additive fine aggregate has been investigated. • Experimental results are verified by computationally from composition of synthesized samples. • Work focuses on shielding materials for nuclear systems including spent fuel storage and drycasks. - Abstract: Incorporation of barite-fluorspar mine waste (BFMW) as a fine aggregate additive has been investigated for its effect on the mechanical and shielding properties of cement mortar. Several mortar mixtures were prepared with different proportions of BFMW ranging from 0% to 30% as fine aggregate replacement. Cement mortar mixtures were evaluated for density, compressive and tensile strengths, and gamma ray radiation shielding. The results revealed that the mortar mixes containing 25% BFMW reaches the highest compressive strength values, which exceeded 50 MPa. Evaluation of gamma-ray attenuation was both measured by experimental tests and computationally calculated using MicroShield software package, and results have shown that using BFMW aggregates increases attenuation coefficient by about 20%. These findings have demonstrated that the mine waste can be suitably used as partial replacement aggregate to improve radiation shielding as well as to reduce the mortar and concrete costs.

  7. Strength and Density of Geopolymer Mortar Cured at Ambient Temperature for Use as Repair Material

    Science.gov (United States)

    Warid Wazien, A. Z.; Bakri Abdullah, Mohd Mustafa Al; Abd. Razak, Rafiza; Mohd Remy Rozainy, M. A. Z.; Faheem Mohd Tahir, Muhammad

    2016-06-01

    Geopolymers produced by synthesizing aluminosilicate source materials with an alkaline activator solution promised an excellent properties akin to the existing construction material. This study focused on the effect of various binder to sand ratio on geopolymer mortar properties. Mix design of geopolymer mortar was produced using NaOH concentration of 12 molars, ratio of fly ash/alkaline activator and ratio Na2SiO3/NaOH of 2.0 and 2.5 respectively. Samples subsequently ware cured at ambient temperature. The properties of geopolymer mortar were analysed in term of compressive strength and density at different period which are on the 3rd and 7th day of curing. Experimental results revealed that the addition of sand slightly increase the compressive strength of geopolymer. The optimum compressive strength obtained was up to 31.39 MPa on the 7th day. The density of geopolymer mortar was in the range between 2.0 g/cm3 to 2.23 g/cm3. Based on this findings, the special properties promoted by geopolymer mortar display high potential to be implemented in the field of concrete patch repair.

  8. Calcium Extraction from Blast-Furnace-Slag-Based Mortars in Sulphate Bacterial Medium

    Directory of Open Access Journals (Sweden)

    Adriana Estokova

    2018-01-01

    Full Text Available Wastewater structures, such as treatment plants or sewers can be easily affected by bio-corrosion influenced by microorganisms living in waste water. The activity of these microbes results in deterioration and can cause the reduction in structural performance of such structures. In order to improve the durability of mortar and concrete, different admixtures are being used and the best impact is observed in cement based materials combined with blast furnace slag. In this study, mortar samples with blast furnace slag were exposed to bacterial sulphate attack for 90 and 180 days. The leaching of calcium ions from the cement matrix and equivalent damaged depths of studied mortar samples were evaluated. The results showed more significant leaching of samples placed in bacterial environment, compared to the samples placed in non-bacterial environment. Similarly, the equivalent damaged depths of mortars were much higher for the bacteria-influenced samples. The slag-based cement mortars did not clearly show improved resistance in bacterial medium in terms of calcium leaching.

  9. Characterization of a new protocol for mortar dating: 13C and 14C evidences

    International Nuclear Information System (INIS)

    Marzaioli, F.

    2011-01-01

    This paper reviews the present knowledge about the analysis of mortars in the framework of artworks absolute chronology determination with the aim to formulate a new methodology capable of systematically and accurately estimating the age of these constructive and/or art materials. The core of the proposed methodology is represented by a physical procedure (ultrasonication) selecting only carbonaceous materials represented by carbonates formed after the absorption of atmospheric Co2 (carbonatation) by mortars (binder) during their setting. With the aim to evaluate the procedure efficiency in the isolation of binder signal from the most important source of carbonates, the proposed procedure was tested on a series of laboratory mortars produced, in a simplified version, in the laboratory environment. Mortar production was characterized by means of a series of measurements allowing to draw important indications about the applied procedure. The radiocarbon value of isolated binder carbonates was compared with the Co2 signal sampled form laboratory air during mortar setting. The observed results confirmed preliminarily the good protocol accuracy for radiocarbon dating suggesting its capability for the application to real study cases.

  10. Acoustic Behavior of Subfloor Lightweight Mortars Containing Micronized Poly (Ethylene Vinyl Acetate) (EVA).

    Science.gov (United States)

    Brancher, Luiza R; Nunes, Maria Fernanda de O; Grisa, Ana Maria C; Pagnussat, Daniel T; Zeni, Mára

    2016-01-15

    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.

  11. Alkali activated slag mortars provide high resistance to chloride-induced corrosion of steel

    Science.gov (United States)

    Criado, Maria; Provis, John L.

    2018-06-01

    The pore solutions of alkali-activated slag cements and Portland-based cements are very different in terms of their chemical and redox characteristics, particularly due to the high alkalinity and high sulfide content of alkali-activated slag cement. Therefore, differences in corrosion mechanisms of steel elements embedded in these cements could be expected, with important implications for the durability of reinforced concrete elements. This study assesses the corrosion behaviour of steel embedded in alkali-activated blast furnace slag (BFS) mortars exposed to alkaline solution, alkaline chloride-rich solution, water, and standard laboratory conditions, using electrochemical techniques. White Portland cement (WPC) mortars and blended cement mortars (white Portland cement and blast furnace slag) were also tested for comparative purposes. The steel elements embedded in immersed alkali-activated slag mortars presented very negative redox potentials and high apparent corrosion current values; the presence of sulfide reduced the redox potential, and the oxidation of the reduced sulfur-containing species within the cement itself gave an electrochemical signal that classical electrochemical tests for reinforced concrete durability would interpret as being due to steel corrosion processes. However, the actual observed resistance to chloride-induced corrosion was very high, as measured by extraction and characterisation of the steel at the end of a 9-month exposure period, whereas the steel embedded in white Portland cement mortars was significantly damaged under the same conditions.

  12. Lime-pozzolana mortars in Roman catacombs: composition, structures and restoration

    International Nuclear Information System (INIS)

    Sanchez-Moral, Sergio; Luque, Luis; Canaveras, Juan-Carlos; Soler, Vicente; Garcia-Guinea, Javier; Aparicio, Alfredo

    2005-01-01

    Analyses of microsamples collected from Roman catacombs and samples of lime-pozzolana mortars hardened in the laboratory display higher contents in carbonated binder than other subaerial Roman monuments. The measured environmental data inside the Saint Callistus and Domitilla catacombs show a constant temperature of 15-17 deg C, a high CO 2 content (1700 to 3500 ppm) and a relative humidity close to 100%. These conditions and particularly the high CO 2 concentration speed-up the lime calcitization roughly by 500% and reduce the cationic diffusion to form hydrous calcium aluminosilicates. The structure of Roman catacomb mortars shows (i) coarser aggregates and thicker beds on the inside, (ii) thin, smoothed, light and fine-grained external surfaces with low content of aggregates and (iii) paintings and frescoes on the outside. The observed high porosity of the mortars can be attributed to cracking after drying linked with the high binder content. Hardened lime lumps inside the binder denote low water/mortar ratios for slaking. The aggregate tephra pyroclasts rich in aluminosilicate phases with accessorial amounts of Ba, Sr, Rb, Cu and Pb were analysed through X-ray diffraction (XRD), electron microprobe analysis (EMPA) and also by environmental scanning electron microscopy (ESEM) to identify the size and distribution of porosity. Results support procedures using local materials, special mortars and classic techniques for restoration purposes in hypogeal backgrounds

  13. Crushed and River-Origin Sands Used as Aggregates in Repair Mortars

    Directory of Open Access Journals (Sweden)

    Maria Stefanidou

    2016-04-01

    Full Text Available The systematic analysis of mortars from monuments or historic buildings and the simultaneous study of the construction environment show that it was common practice to use naturally occurring sand from local rivers or streams for the production of the mortars. There are cases though, mainly on islands, where sands of natural origin were limited, and marine or crushed sands were used possibly after elaboration. In all cases the particle size analysis of old mortar confirms the presence of even distribution of the granules. As regards the design of the repair mortars, there are criteria that should be taken into consideration in order to produce materials with compatible properties. The main properties concerning sands are the grain distribution and maximum size, the color, the content of fines, and soluble salts. The objective of this research is the study of the physical characteristics of the sands such as the sand equivalent, the gradation, the apparent density, the morphology of the grains, their mineralogical composition and the influence of these properties on the behavior of lime mortars, notably the mechanical and physical properties acquired.

  14. 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.

  15. 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.

  16. Coupled Effect of Elevated Temperature and Cooling Conditions on the Properties of Ground Clay Brick Mortars

    Science.gov (United States)

    Ali Abd El Aziz, Magdy; Abdelaleem, Salh; Heikal, Mohamed

    2013-12-01

    When a concrete structure is exposed to fire and cooling, some deterioration in its chemical resistivity and mechanical properties takes place. This deterioration can reach a level at which the structure may have to be thoroughly renovated or completely replaced. In this investigation, four types of cement mortars, ground clay bricks (GCB)/sand namely 0/3, 1/2, 2/1 and 3/0, were used. Three different cement contents were used: 350, 400 and 450 kg/m3. All the mortars were prepared and cured in tap water for 3 months and then kept in laboratory atmospheric conditions up to 6 months. The specimens were subjected to elevated temperatures up to 700°C for 3h and then cooled by three different conditions: water, furnace, and air cooling. The results show that all the mortars subjected to fire, irrespective of cooling mode, suffered a significant reduction in compressive strength. However, the mortars cooled in air exhibited a relativity higher reduction in compressive strength rather than those water or furnace cooled. The mortars containing GCB/sand (3/0) and GCB/sand (1/2) exhibited a relatively higher thermal stability than the others.

  17. 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.

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

    International Nuclear Information System (INIS)

    Naceri, Abdelghani; Hamina, Makhloufi Chikouche

    2009-01-01

    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.

  19. 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.

  20. 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.

  1. an Adhesive Patch

    Directory of Open Access Journals (Sweden)

    S. Mojtaba Taghizadeh

    2013-01-01

    Full Text Available Drug-in-adhesive transdermal drug delivery systems  TDDSs containing stimulants, termed as energetic substances, such as caffeine and pantothenic acid, were studied. Caffeine is a white crystalline substance and a stimulant to central nervous system. In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness. Pantothenic acid, also recognized as vitamin B5, is a water-soluble vitamin. For many animals, pantothenic acid is an essential nutrient. Animals require pantothenic acid to synthesize and metabolize proteins, carbohydrates and fats. For this purpose caffeine and pantothenic acid were  used  as  drug  components with  6.32%  and  1.12%  loadings,  in  different functional and non-functional acrylic pressure sensitive adhesives (PSAs of 52.89%, respectively. Ethylene glycol as a chemical enhancer was used in all TDDSs with 39.67%. The effect of PSAs  type on  in vitro  release and adhesion properties  (peel strength and tack values from drug delivery devices were evaluated. It was found that TDDS containing -COOH functional PSA showed  the  lowest steady state fux. The adhesion properties of the samples were improved by addition of functional acrylic PSA in formulations.

  2. Leukocyte adhesion deficiencies

    NARCIS (Netherlands)

    van de Vijver, Edith; van den Berg, Timo K.; Kuijpers, Taco W.

    2013-01-01

    During inflammation, leukocytes play a key role in maintaining tissue homeostasis through elimination of pathogens and removal of damaged tissue. Leukocytes migrate to the site of inflammation by crawling over and through the blood vessel wall, into the tissue. Leukocyte adhesion deficiencies (ie,

  3. Adhesive tape exfoliation

    DEFF Research Database (Denmark)

    Bohr, Jakob

    2015-01-01

    Single-crystal graphite can be cleaved by the use of an adhesive tape. This was also the initial route for obtaining graphene, a one-layer thick graphite slab. In this letter a few simple and fun considerations are presented in an attempt to shed some light on why this procedure is successful...

  4. Wood Composite Adhesives

    Science.gov (United States)

    Gomez-Bueso, Jose; Haupt, Robert

    The global environment, in which phenolic resins are being used for wood composite manufacture, has changed significantly during the last decade. This chapter reviews trends that are driving the use and consumption of phenolic resins around the world. The review begins with recent data on volume usage and regional trends, followed by an analysis of factors affecting global markets. In a section on environmental factors, the impact of recent formaldehyde emission regulations is discussed. The section on economics introduces wood composite production as it relates to the available adhesive systems, with special emphasis on the technical requirement to improve phenolic reactivity. Advances in composite process technology are introduced, especially in regard to the increased demands the improvements place upon adhesive system performance. The specific requirements for the various wood composite families are considered in the context of adhesive performance needs. The results of research into current chemistries are discussed, with a review of recent findings regarding the mechanisms of phenolic condensation and acceleration. Also, the work regarding alternate natural materials, such as carbohydrates, lignins, tannins, and proteinaceous materials, is presented. Finally, new developments in alternative adhesive technologies are reported.

  5. Preparation of starch-g-polyacrylamide and its utilization as an adhesive for wood, paper and glass

    International Nuclear Information System (INIS)

    Abu-Ayana, Y.M.; Abou Zeid, N.Y.; Asran, A.Sh.; Aly, A.S.

    2005-01-01

    Starch- based adhesives are capable of wetting polar surfaces such as cellulose, penetrating pores, and forming strong bonds through mechanical and physical bonds. This paper studies the modification of starch by grafting with acrylamide, and the relation between modification and adhesion properties. Six formulae are prepared from modified and unmodified starch, and evaluated as adhesives for wood, glass, carton, and paper. Study of the factors affecting the adhesive bond is performed. Promising results are obtained. The adhesive formulae I-VI can be used successfully as paper and carton adhesives. Formulae I, TI and III can be used as wood adhesives. Excellent value for shear strength using formula No. I, comparable with other known thermoplastic and thermoset adhesives., formula I also can be used as glass adhesive, but in narrow applications and in absence of water

  6. Adhesive bonding of wood materials

    Science.gov (United States)

    Charles B. Vick

    1999-01-01

    Adhesive bonding of wood components has played an essential role in the development and growth of the forest products industry and has been a key factor in the efficient utilization of our timber resource. The largest use of adhesives is in the construction industry. By far, the largest amounts of adhesives are used to manufacture building materials, such as plywood,...

  7. Effect of ionizing radiation on properties of acrylic pressure sensitive adhesives

    International Nuclear Information System (INIS)

    Panta, P.P.; Zimek, Z.A.; Giuszewski, W.; Kowalewski, R.; Wojtynska, E.; Wnuk, A.

    1998-01-01

    Pressure-sensitive adhesives for technical application are widely produced. The biological properties of adhesives depend on the type of monomers used. The available literature data as experience of the authors of this study in the area of pressure-sensitive acrylic adhesive, polymers used in medicine, polymerisation in aqueous media, radiation sterilization, permit to make an assumption that it is possible to elaborate the technology of production of pressure-sensitive adhesives in aqueous emulsion for medical applications. Identification of phenomena influencing the adhesive properties, especially its adhesion, cohesion, tack and durability is of great importance. The control of polymer structure is performed by means of adequate selection of conditions of synthesis and parameters of radiation processing. The authors investigate the influence on the final products of such factors as the type and amount of monomers used, their mutual ratio, as well as the ratio monomers and the dose of ionising radiation. There is no available literature information concerning the investigation of resistance of acrylic emulsion adhesive to sterilisation by electron beam. It is known from unpublished research that some adhesives are resistant to radiation, while others undergo destruction. It probably depends on the composition of emulsion, specifically on the additives which modify adhesives. Simultaneous achievement of good cohesion and adhesion in the case of such types of pressure sensitive adhesives is very difficult pressure sensitive adhesives is very difficult

  8. Generation of Rayleigh waves into mortar and concrete samples.

    Science.gov (United States)

    Piwakowski, B; Fnine, Abdelilah; Goueygou, M; Buyle-Bodin, F

    2004-04-01

    The paper deals with a non-destructive method for characterizing the degraded cover of concrete structures using high-frequency ultrasound. In a preliminary study, the authors emphasized on the interest of using higher frequency Rayleigh waves (within the 0.2-1 MHz frequency band) for on-site inspection of concrete structures with subsurface damage. The present study represents a continuation of the previous work and aims at optimizing the generation and reception of Rayleigh waves into mortar and concrete be means of wedge transducers. This is performed experimentally by checking the influence of the wedge material and coupling agent on the surface wave parameters. The selection of the best combination wedge/coupling is performed by searching separately for the best wedge material and the best coupling material. Three wedge materials and five coupling agents were tested. For each setup the five parameters obtained from the surface wave measurement i.e. the frequency band, the maximal available central frequency, the group velocity error and its standard deviation and finally the error in velocity dispersion characteristic were investigated and classed as a function of the wedge material and the coupling agent. The selection criteria were chosen so as to minimize the absorption of both materials, the randomness of measurements and the systematic error of the group velocity and of dispersion characteristic. Among the three tested wedge materials, Teflon was found to be the best. The investigation on the coupling agent shows that the gel type materials are the best solutions. The "thick" materials displaying higher viscosity were found as the worst. The results show also that the use of a thin plastic film combined with the coupling agent even increases the bandwidth and decreases the uncertainty of measurements.

  9. Highly permeable, cement-bounded backfilling mortars for SMA repositories

    International Nuclear Information System (INIS)

    Jacobs, F.; Mayer, G.; Wittmann, F.H.

    1994-03-01

    In low- and intermediate-level waste repositories, gas is produced due e.g. to corrosion. This gas must be able to escape from the repository in order to prevent damage to the repository structure. A cement-based backfill should take over this function. For this purpose, the composition of cement-based materials was varied to study their influence on porosity and permeability. In parallel to this study the behaviour of fresh concrete, the liberation of the heat of hydration and the hardened concrete properties were investigated. To characterize the permeability of cement-based materials the following parameters are important: 1) composition of the material (pore fabric), 2) storage conditions (degree of saturation), 3) degree of hydration (age), 4) measuring fluid. A change in the composition of cement-based materials can vary the permeability by ten orders of magnitude. It is shown that, by using dense aggregates, the transport of the fluid takes place through the matrix and along the aggregate/matrix interface. By using porous aggregates the permeability can be increased by two orders of magnitude. In the case of a dense matrix, porous aggregates do not alter the permeability. Increasing the matrix content or interface content increases permeability. Hence light weight mortars are an obvious choice. Like-grained mixes showed higher permeabilities in combination with better mechanical properties but, in comparison to normal mixes, they showed worse flow properties. With the composition cement-: water-: aggregate content 1:0.4:5.33 the likegrained mix with aggregates ranging from 2 to 3 mm proved to be a suitable material. With a low compaction after 28 days this mix reaches a permeability of 4.10 -12 m 2 and an uniaxial cylinder compressive strength of 16 N/mm 2 . (author) 58 figs., 23 tabs., refs

  10. Commercial NHL-containing mortars for the preservation of historical architecture. Part 1: Compositional and mechanical characterisation

    NARCIS (Netherlands)

    Nijland, T.G.; Gulotta, D.; Goidanich, S.; Tedeschi, C.; Toniolo, L.

    2013-01-01

    This paper presents the characterisation of a selection of NHL-based commercial products for the conservation of historic masonries. Two binders and four ready-mixed mortars have been analysed; both the anhydrous raw materials and the hardened mortars have been studied, focusing on those parameters

  11. Properties, characterization, and decay of sticky rice–lime mortars from the Wugang Ming dynasty city wall (China)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Ya [State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083 (China); Cultural Relics and Archaeology Institute of Hunan, Changsha 410083 (China); Fu, Xuan; Gu, Haibing [Cultural Relics and Archaeology Institute of Hunan, Changsha 410083 (China); Gao, Feng [State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083 (China); Liu, Shaojun, E-mail: liumatthew@csu.edu.cn [State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083 (China)

    2014-04-01

    Urgent restoration of the Wugang Ming dynasty city wall brings about the need for a study of the formulation and properties of mortars. In the present paper, mortar samples from the Wugang Ming dynasty city wall were characterized in a combination of sheet polarized light optical microscopy, scanning electron microscopy with X-ray energy dispersive spectrometer, thermogravimetric/differential scanning calorimetry, X-ray powder diffraction, Fourier transform infrared spectroscopy, and inductively coupled plasma emission spectroscopy. Results show that mortars are mainly built up from inorganic calcium carbonate based organic–inorganic hybrid material with a small amount of sticky rice, which plays a crucial role in forming dense and compact microstructure of mortars and effectively hindering penetration of water and air into mortars. Analysis of decayed products shows that the detrimental soluble salts originates from ambient environment. - Highlights: • Mortars used in the Wugang city wall are a calcium carbonate-sticky rice hybrid bonding material. • Carbonation processing is extremely slow due to dense and compact microstructure of mortars. • Decying of mortars results from the appearance of soluble salt from ambient environment.

  12. Influence of Titanium Dioxide Nanoparticles on the Sulfate Attack upon Ordinary Portland Cement and Slag-Blended Mortars

    Directory of Open Access Journals (Sweden)

    Atta-ur-Rehman

    2018-02-01

    Full Text Available In this study, the effects of titanium dioxide (TiO2 nanoparticles on the sulfate attack resistance of ordinary Portland cement (OPC and slag-blended mortars were investigated. OPC and slag-blended mortars (OPC:Slag = 50:50 were made with water to binder ratio of 0.4 and a binder to sand ratio of 1:3. TiO2 was added as an admixture as 0%, 3%, 6%, 9% and 12% of the binder weight. Mortar specimens were exposed to an accelerated sulfate attack environment. Expansion, changes in mass and surface microhardness were measured. Scanning Electron Microscopy (SEM, Energy Dispersive Spectroscopy (EDS, X-ray Diffraction (XRD, Thermogravimetry Analysis (TGA and Differential Scanning Calorimetry (DSC tests were conducted. The formation of ettringite and gypsum crystals after the sulfate attack were detected. Both these products had caused crystallization pressure in the microstructure of mortars and deteriorated the mortars. Our results show that the addition of nano-TiO2 accelerated expansion, variation in mass, loss of surface microhardness and widened cracks in OPC and slag-blended mortars. Nano-TiO2 containing slag-blended mortars were more resistant to sulfate attack than nano-TiO2 containing OPC mortars. Because nano-TiO2 reduced the size of coarse pores, so it increased crystallization pressure due to the formation of ettringite and gypsum thus led to more damage under sulfate attack.

  13. Microstructural Characterization of Reinforced Mortar after Corrosion and Cathodic Prevention in the Presence of Core-Shell Micelles

    NARCIS (Netherlands)

    Koleva, D.A.

    2010-01-01

    This work reports on the microstructural properties of reinforced mortar after chloride-induced corrosion and two regimes of cathodic prevention. Additionally, the impact of a very low concentration polymeric nano-aggregates (core-shell micelles from PEO113-b-PS218), admixed in the mortar mixture is

  14. Properties, characterization, and decay of sticky rice–lime mortars from the Wugang Ming dynasty city wall (China)

    International Nuclear Information System (INIS)

    Xiao, Ya; Fu, Xuan; Gu, Haibing; Gao, Feng; Liu, Shaojun

    2014-01-01

    Urgent restoration of the Wugang Ming dynasty city wall brings about the need for a study of the formulation and properties of mortars. In the present paper, mortar samples from the Wugang Ming dynasty city wall were characterized in a combination of sheet polarized light optical microscopy, scanning electron microscopy with X-ray energy dispersive spectrometer, thermogravimetric/differential scanning calorimetry, X-ray powder diffraction, Fourier transform infrared spectroscopy, and inductively coupled plasma emission spectroscopy. Results show that mortars are mainly built up from inorganic calcium carbonate based organic–inorganic hybrid material with a small amount of sticky rice, which plays a crucial role in forming dense and compact microstructure of mortars and effectively hindering penetration of water and air into mortars. Analysis of decayed products shows that the detrimental soluble salts originates from ambient environment. - Highlights: • Mortars used in the Wugang city wall are a calcium carbonate-sticky rice hybrid bonding material. • Carbonation processing is extremely slow due to dense and compact microstructure of mortars. • Decying of mortars results from the appearance of soluble salt from ambient environment

  15. 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

    Air pollution control (APC) residues from municipal solid waste incineration (MSWI) are considered hazardous waste and need pretreatment prior to possible reuse. Here, two MSWI APC residues, from which the most mobile fraction of heavy metals and salts has been removed by carbonation and/or elect......Air pollution control (APC) residues from municipal solid waste incineration (MSWI) are considered hazardous waste and need pretreatment prior to possible reuse. Here, two MSWI APC residues, from which the most mobile fraction of heavy metals and salts has been removed by carbonation and....../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...

  16. 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.

  17. Influence of citric acid as setting retarder in CPV portland cement pastes and mortars

    International Nuclear Information System (INIS)

    Mendes, B.C.; Lopes, M.M.S.; Alvarenga, R.C.S.S.; Fassoni, D.P.; Pedroti, L.G.; Azevedo, A.R.G. de

    2016-01-01

    This work aims to study the availability of using and the influence of citric acid in the properties of pastes and mortars made with Portland cement CPV ARI both in fresh and hardened form. The citric acid dosages were 0, 0.4%, and 0.8% relative to the cement mass. The produced cement pastes were tested to determine normal consistency water and initial and final setting times. Mortars were tested to determine the consistency index, specific gravity, air entrained content in the fresh stage, hardened bulk density, compressive strength at ages 7, 14, and 28 days, and analysis by XRD technique. The results show that citric acid, besides improve the mortar workability, contribute to an increase in mechanical strength in older than 14 days. (author)

  18. Study of water retention capacity in mortars with the incorporation of exhaust powder

    International Nuclear Information System (INIS)

    Pereira, Helena Ravache Samy; Valentina, Luiz Veriano Oliveira Dalla; Priscila Warch

    2011-01-01

    The purpose of this study is to suggest the incorporation of exhaust powder waste in mortars for laying and coating walls and ceilings, to evaluate the representative proportions through mixture design, aiming for a satisfactory performance of the analyzed property and the water retention capacity. In the experimental procedure ten mixtures were performed with consistence index of 230±10mm. The surface response generated showed a water retention capacity in mortar varying from 88% to 95%, which could be classified as normal and high. In relation to the water retention, the incorporation of foundry exhaust powder waste in the studied proportions is viable in mortars for laying and coating walls and ceilings. (author)

  19. Effect of brief heat-curing on microstructure and mechanical properties in fresh cement based mortars

    International Nuclear Information System (INIS)

    Ballester, P.; Hidalgo, A.; Marmol, I.; Morales, J.; Sanchez, L.

    2009-01-01

    The effect of temperature on fresh mortar and cement paste was evaluated by simulating the curing conditions of external buildings plastering applied under extremely hot weather. The specimens were heated at controlled temperatures in the 40-80 o C range by exposure to IR radiation over short periods. The effect of soaking for a short time was also examined. The results of compressive strength tests, scanning electron microscopy, infrared spectroscopy and mercury porosimetry helped to characterize the mechanical and physico-chemical properties of the studied sample. Early age behaviour (28 days) in neat cement was barely affected by the temperature. By contrast, exposure to high temperatures caused significant microstructural changes in the mortar. However, successive soaking over short periods was found to reactivate the mechanism of curing and restore the expected mechanical properties. Based on the results, application of cement based mortar at high temperatures is effective when followed by a short, specific soaking process.

  20. Influence of bicarbonate ions on the deterioration of mortar bars in sulfate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kunther, W., E-mail: Wolfgang.Kunther@empa.ch [Empa, Laboratory for Concrete and Construction Chemistry, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Lothenbach, B. [Empa, Laboratory for Concrete and Construction Chemistry, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Scrivener, K. [EPFL, Laboratory of Construction Materials, CH-1015 Lausanne (Switzerland)

    2013-02-15

    This work investigates the influence of bicarbonate ions on the deterioration of cementitious material exposed to sulfate ions. Mortars based on a CEM I and on a CEM III/B cement were investigated. Experimental investigations were compared to thermodynamic modeling and phase characterization to understand the differences in deterioration. The presence of bicarbonate ions significantly reduced the expansion of the CEM I mortars. Thermodynamic modeling showed that at high concentrations of bicarbonate ettringite and gypsum become unstable. Microstructural characterization combined with information from thermodynamic modeling suggests that conditions of high supersaturation with respect to ettringite are unlikely in the samples exposed in solutions containing bicarbonate. Consequently, expansive forces are not generated by the crystallization pressure of ettringite. There was little expansion of the CEM III/B sample even in the sodium sulfate solution. In the bicarbonate solution this mortar showed a highly leached zone at the surface in which calcite was observed.