Cement-based materials are fundamental in the construction industry,and enhancing their properties is an ongoing challenge.The use of superabsorbent polymers(SAP)has gained significant attention as a possible way to i...Cement-based materials are fundamental in the construction industry,and enhancing their properties is an ongoing challenge.The use of superabsorbent polymers(SAP)has gained significant attention as a possible way to improve the performance of cement-based materials due to their unique water-absorption and retention properties.This study investigates the multifaceted impact of kaolin intercalation-modified superabsorbent polymers(K-SAP)on the properties of cement mortar.The results show that K-SAP significantly affects the cement mortar’s rheological behavior,with distinct phases of water absorption and release,leading to changes in workability over time.Furthermore,K-SAP alters the hydration kinetics,delaying the exothermic peak of hydration and subsequently modifying the heat release kinetics.Notably,K-SAP effectively maintains a higher internal relative humidity within the mortar,reducing the autogenous shrinkage behavior.Moreover,K-SAP can have a beneficial effect on pore structure and this can be ascribed to the internal curing effect of released water from K-SAP.展开更多
To investigate the influences of different admixtures on the drying shrinkage of polymer mortar in a metakaolin base,the experiments of VAE(vinyl acetate ethylene copolymer),APAM(anionic polyacrylamide)and CPAM(cation...To investigate the influences of different admixtures on the drying shrinkage of polymer mortar in a metakaolin base,the experiments of VAE(vinyl acetate ethylene copolymer),APAM(anionic polyacrylamide)and CPAM(cationic polyacrylamide)on the drying shrinkage properties of geopolymer mortar were designed under normal temperature curing conditions.An SP-175 mortar shrinkage dilatometer was introduced to measure the dry shrinkage of geopolymer mortar.Meanwhile,the drying shrinkage properties of geopolymer mortar are exhibited by the parameters of water loss rate,drying shrinkage rate,drying shrinkage strain and drying shrinkage coefficient.The experimental data are further fitted to obtain the prediction model of dry shrinkage of geopolymer mortar,which can better reflect the relationship between dry shrinkage rate and time.Finally,the experimental results demonstrate that the dry shrinkage of geopolymer mortar can be significantly increased by adding 4%VAE admixture,meanwhile under the condition that the polymer film formed by VAE reaction can strengthen and toughen the mortar.2.5%APAM admixture and 1.5%CPAM admixture can enhance the dry shrinkage performance of geopolymer mortar in a certain range.展开更多
Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexur...Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexural strength, brittleness index （σF/σC） and abrasion resistance can be improved significantly by the addition of PP fiber and SBR polymer latex. The relationship between the flexural strength and abrasion resistance was analyzed, showing a good linear relationship between them. The reinforced mechanism of PP fiber and SBR polymer latex on cement mortar was analyzed by some microscopic tests. The test results show that the addition of SBR polymer latex has no significant influence on the cement hydration after 7 d curing. Adding SBR polymer latex into cement mortar can form a polymer transition layer in the interfaces of PP fiber and cement hydrates, which improves the bonding properties between the PP fiber and cement mortar matrix effectively.展开更多
At present, the basic technical principle in China is to adopt polymers to modifying the properties of mortar so as to improve the crack-resistance of construction structures and to strengthen their water-resisting an...At present, the basic technical principle in China is to adopt polymers to modifying the properties of mortar so as to improve the crack-resistance of construction structures and to strengthen their water-resisting and climate-resisting properties as well. However, how polymer acts on anti-crack mortar is short of systematic research. Theoretical exposition of polymer mortar is basically explained by Ohama Model, which is cement slaking and polymer coating are carried on together and mutually-cross web structure interweaved with liquid and polymer coating. But anti-crack mortar has its own special characteristics because of fewer polymers mixed in it and its high viscosity. So this paper is to showing how different polymers affect its crack-resistance cannot be reflected from this theory. Vinyl-acetate ethylene (VAC/E) has been selected as representation of polymerization, whose property is modified by compounding it from some inorganic components, such as talc, CaCO3 and so on. And then the mechanics property and shrinkage of anti-crack polymer mortar is tested when different amount of polymers is added as admixture of mortar. The result indicates that, the working performance and mechanics property of the polymer mortar are worse mixed VAC/E only. It basically meets the demands for mechanics strength and working performance when mixed both VAC/E and CaCO3 While it achieves much better mechanical property and working performance than the two former when mixed VAC/E, talc and CaCO3; the result of corresponding scanning electron microscopy (SEM) of sample indicates that the internal result of the polymer mortar, compared with classical Ohama Model, has a particularity that its structure is formed by polymer coating instead of filling up the intervals among cement grains.展开更多
基金the National Natural Science Foundation of China(52172017 and 51902095).
文摘Cement-based materials are fundamental in the construction industry,and enhancing their properties is an ongoing challenge.The use of superabsorbent polymers(SAP)has gained significant attention as a possible way to improve the performance of cement-based materials due to their unique water-absorption and retention properties.This study investigates the multifaceted impact of kaolin intercalation-modified superabsorbent polymers(K-SAP)on the properties of cement mortar.The results show that K-SAP significantly affects the cement mortar’s rheological behavior,with distinct phases of water absorption and release,leading to changes in workability over time.Furthermore,K-SAP alters the hydration kinetics,delaying the exothermic peak of hydration and subsequently modifying the heat release kinetics.Notably,K-SAP effectively maintains a higher internal relative humidity within the mortar,reducing the autogenous shrinkage behavior.Moreover,K-SAP can have a beneficial effect on pore structure and this can be ascribed to the internal curing effect of released water from K-SAP.
基金Funded by the the Shaanxi Provincial Natural Science Basic Research Plan(No.2021JQ-471)the Natural Science Project of Shaanxi Provincial Department of Education(No.21JK0802)。
文摘To investigate the influences of different admixtures on the drying shrinkage of polymer mortar in a metakaolin base,the experiments of VAE(vinyl acetate ethylene copolymer),APAM(anionic polyacrylamide)and CPAM(cationic polyacrylamide)on the drying shrinkage properties of geopolymer mortar were designed under normal temperature curing conditions.An SP-175 mortar shrinkage dilatometer was introduced to measure the dry shrinkage of geopolymer mortar.Meanwhile,the drying shrinkage properties of geopolymer mortar are exhibited by the parameters of water loss rate,drying shrinkage rate,drying shrinkage strain and drying shrinkage coefficient.The experimental data are further fitted to obtain the prediction model of dry shrinkage of geopolymer mortar,which can better reflect the relationship between dry shrinkage rate and time.Finally,the experimental results demonstrate that the dry shrinkage of geopolymer mortar can be significantly increased by adding 4%VAE admixture,meanwhile under the condition that the polymer film formed by VAE reaction can strengthen and toughen the mortar.2.5%APAM admixture and 1.5%CPAM admixture can enhance the dry shrinkage performance of geopolymer mortar in a certain range.
基金Funded by the Science Project from Department of Communication of Hubei Province
文摘Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexural strength, brittleness index （σF/σC） and abrasion resistance can be improved significantly by the addition of PP fiber and SBR polymer latex. The relationship between the flexural strength and abrasion resistance was analyzed, showing a good linear relationship between them. The reinforced mechanism of PP fiber and SBR polymer latex on cement mortar was analyzed by some microscopic tests. The test results show that the addition of SBR polymer latex has no significant influence on the cement hydration after 7 d curing. Adding SBR polymer latex into cement mortar can form a polymer transition layer in the interfaces of PP fiber and cement hydrates, which improves the bonding properties between the PP fiber and cement mortar matrix effectively.
基金Funded bv "863" Proaram of China (No. 2005AA332010)
文摘At present, the basic technical principle in China is to adopt polymers to modifying the properties of mortar so as to improve the crack-resistance of construction structures and to strengthen their water-resisting and climate-resisting properties as well. However, how polymer acts on anti-crack mortar is short of systematic research. Theoretical exposition of polymer mortar is basically explained by Ohama Model, which is cement slaking and polymer coating are carried on together and mutually-cross web structure interweaved with liquid and polymer coating. But anti-crack mortar has its own special characteristics because of fewer polymers mixed in it and its high viscosity. So this paper is to showing how different polymers affect its crack-resistance cannot be reflected from this theory. Vinyl-acetate ethylene (VAC/E) has been selected as representation of polymerization, whose property is modified by compounding it from some inorganic components, such as talc, CaCO3 and so on. And then the mechanics property and shrinkage of anti-crack polymer mortar is tested when different amount of polymers is added as admixture of mortar. The result indicates that, the working performance and mechanics property of the polymer mortar are worse mixed VAC/E only. It basically meets the demands for mechanics strength and working performance when mixed both VAC/E and CaCO3 While it achieves much better mechanical property and working performance than the two former when mixed VAC/E, talc and CaCO3; the result of corresponding scanning electron microscopy (SEM) of sample indicates that the internal result of the polymer mortar, compared with classical Ohama Model, has a particularity that its structure is formed by polymer coating instead of filling up the intervals among cement grains.
