聚羧酸減水劑與減縮劑的相容性研究
發(fā)布時間：2018-10-31 14:06
【摘要】：高性能混凝土由于其具有優(yōu)良的工作性能、高強和耐久性好的突出優(yōu)勢而被廣泛研究和應用。高效減水劑的應用是實現(xiàn)混凝土高性能化的必要技術手段，正是高效減水劑的應用使混凝土實現(xiàn)（超）低水膠比成為可能。然而高性能混凝土采用（超）低水膠比時，混凝土體積收縮顯著，由此引起的開裂風險大大提高。因此研究改善高性能混凝土體積收縮導致開裂影響耐久性的相關問題迫在眉睫。減縮劑是一種能從本質(zhì)上顯著抑制混凝土收縮的化學外加劑，近年來受到越來越多的關注和重視，因此減縮劑的應用將來可能成為一種趨勢。利用高效減水劑和減縮劑以實現(xiàn)高性能混凝土優(yōu)良的工作性能和低收縮效果時，，兩者將不可避免在混凝土中共同使用，因此研究高效減水劑和減縮劑共同使用可能引起的一系列相容性問題具有積極的理論價值和實際意義。 本文對高效減水劑與減縮劑相容性的研究主要從兩者共同使用時對減水劑塑化效果的影響、對減縮劑減縮效果以及對水泥基材料力學性能的影響來展開。在此基礎上，采用紫外-可見光分光光度計（UV）、Zeta電位儀、熒光光譜儀、X射線衍射（XRD）及氮吸附分析儀等分析手段對聚羧酸減水劑與減縮劑相容性機理進行研究，結果表明： 減縮劑對聚羧酸減水劑塑化效果基本不存在負面影響，對凈漿流動度甚至有增大作用；聚羧酸減水劑與減縮劑同摻后對水泥基材料的減縮效果增強；減縮劑3.0%摻量下，減縮劑（SRA-SBT）與醚類聚羧酸減水劑（PC1）同摻后砂漿強度僅為單摻PC1組的78.6%，低于減縮劑（SRA-G）與PC1同摻組的強度，與酯類聚羧酸減水劑（PC2）同摻后的砂漿強度下降幅度均小于5%，且可以改善減縮劑內(nèi)摻對砂漿力學性能的負面影響；減縮劑與聚羧酸減水劑同摻后混凝土強度較單摻減水劑組下降幅度小于7%，較與萘系減水劑同摻組高5MPa左右。由此可知，PC1與減縮劑SRA-G的相容性優(yōu)于與減縮劑SRA-SBT的相容性，PC2與兩種減縮劑的相容性均較好。 采用UV、zeta電位儀及熒光光譜儀等分析手段，研究了水泥基材料對兩者的吸附、兩者同摻后對水泥漿體zeta電位以及對聚羧酸減水劑微結構的影響，發(fā)現(xiàn)減縮劑的加入會略微降低摻有聚羧酸減水劑的水泥顆粒表面zeta電位，但會明顯降低摻有萘系減水劑的靜電斥力，并且使聚羧酸的根均方半徑增大且PEO支鏈得到伸展，有利于增加其空間位阻勢能，從而可以適當增加聚羧酸減水劑的塑化效果。 通過研究減縮劑存在下對孔隙溶液蒸發(fā)速率、砂漿和混凝土質(zhì)量損失的影響，探討兩者同摻后引起水泥基材料減縮效果變化的原因。減縮劑主要通過降低溶液表面張力來實現(xiàn)對水泥基材料的收縮抑制效果；同時減縮劑能夠增加溶液粘度并減小孔隙溶液的蒸發(fā)速率和在孔隙中的遷移速度，因此使水泥基材料質(zhì)量損失速率降低，也能夠在一定程度上降低其干燥收縮。 采用XRD及氮吸附等分析手段，研究了兩者同摻后對水泥石中氫氧化鈣衍射峰強度、化學結合水含量以及水泥石孔隙結構發(fā)展的影響，探討引起水泥基材料力學性能發(fā)生改變的原因。減縮劑對水泥水化的影響主要表現(xiàn)為不同齡期水泥石中化學結合水以及氫氧化鈣含量的降低，當減縮劑摻量為3.0%時可使水泥石中30nm以上的孔隙顯著增多，孔隙率顯著提高，以上原因均可造成水泥基材料早期強度降低。
[Abstract]:High performance concrete is widely researched and applied due to its excellent performance, high strength and durability. The application of high efficiency water reducer is the necessary technical means to realize the high performance of concrete. It is the application of high efficiency water reducer to make concrete realize (super) low water cement ratio. However, when high performance concrete uses (super) low water cement ratio, the volume shrinkage of concrete is significant, thus the risk of cracking is greatly improved. Therefore, it is urgent to study the related problems of improving the durability of cracking caused by shrinkage of high performance concrete. Shrinkage-reducing agent is a chemical additive which can significantly inhibit concrete shrinkage from nature, and has attracted more and more attention and attention in recent years. Therefore, the application of shrinkage reducing agent may become a trend in the future. When the high-performance concrete excellent working performance and low shrinkage effect are realized by utilizing the high-efficiency water reducing agent and the reducing agent, both of the high-performance water reducing agent and the reducing agent will inevitably be used together in the concrete, Therefore, it is valuable and practical to study a series of compatibility problems which can be caused by co-use of high-efficiency water reducer and reducer. In this paper, the study of compatibility between high-efficiency water reducing agent and shrinkage reducing agent mainly affects the plasticizing effect of water reducing agent, the reducing effect of reducing agent and the influence on the mechanical properties of cement-based material. On the basis of this, the compatibility mechanism of polyacrylate water reducer and reducer was studied by UV-VIS spectrophotometer (UV), Zeta potential instrument, fluorescence spectrometer, Xray diffraction (XRD) and nitrogen adsorption analyzer. It is shown that the shrinkage reducing agent has no negative influence on the plasticizing effect of the polyacrylate water reducing agent, and even has an increasing effect on the fluidity of the net slurry; the shrinkage reducing agent of the polyacetal resin reducing agent and the reducing agent is enhanced with the reduction effect of the cement-based material; and the reducing agent 3 is used. The strength of the shrinkage-reducing agent (SRA-SBT) and the ether-like water-reducing agent (PC1) was 78.6% of the single-mixed PC1 group, lower than the strength of the reducing agent (SRA-G) and PC1, and the decrease of the strength of the mixed mortar with the ester polyacetal resin-reducing agent (PC2). It is less than 5%, and can improve the negative effect of the reducing agent on the mechanical properties of the mortar. The decreasing amplitude of the reducing agent and the water reducing agent in the same admixture with the water reducing agent is less than 7%, and the reducing agent is 5% higher than that of the water reducing agent. Therefore, the compatibility of PC1 with the reducing agent SRA-G is superior to that of the reducing agent SRA-SBT, and PC2 is compatible with the two reducing agents. The adsorption of cement-based materials on the two kinds of cement-based materials was studied by means of UV, zeta potential instrument and fluorescence spectrometer. The influence of the microstructure of water agent shows that the addition of shrinkage reducing agent reduces the surface zeta potential of the cement particle doped with the water reducing agent, but obviously decreases the electrostatic repulsion of the water reducing agent doped with the water reducing agent, increases the root mean square radius of the polyacetal resin and expands the PEO branched chain, which is beneficial to the increase. and the space position resistance potential energy is added, so that the polylactide can be appropriately increased. The effect of reducing agent on the evaporation rate, mortar and concrete mass loss in the presence of shrinkage reducing agent is studied. The shrinkage reduction effect of the cement-based material is realized mainly by reducing the surface tension of the solution, the shrinkage reducing agent can increase the viscosity of the solution and reduce the evaporation rate of the pore solution and the migration speed in the pores, the quality loss rate of the base material is reduced, By means of XRD and nitrogen adsorption, the effects of both the diffraction peak intensity, chemical bonding water content of calcium hydroxide and the development of cement stone pore structure in cement stone were studied. The effect of shrinkage reducing agent on hydration of cement is mainly shown as the decrease of chemical bonding water and calcium hydroxide content in cement stone at different age, and when the amount of shrinkage reducing agent is 3. 0%, it can make it more than 30nm in cement stone. the porosity is obviously increased, the porosity is obviously improved, and the above reasons are all
【學位授予單位】：重慶大學
【學位級別】：碩士
【學位授予年份】：2012
【分類號】：TU528.042
本文編號：2302464
[Abstract]:High performance concrete is widely researched and applied due to its excellent performance, high strength and durability. The application of high efficiency water reducer is the necessary technical means to realize the high performance of concrete. It is the application of high efficiency water reducer to make concrete realize (super) low water cement ratio. However, when high performance concrete uses (super) low water cement ratio, the volume shrinkage of concrete is significant, thus the risk of cracking is greatly improved. Therefore, it is urgent to study the related problems of improving the durability of cracking caused by shrinkage of high performance concrete. Shrinkage-reducing agent is a chemical additive which can significantly inhibit concrete shrinkage from nature, and has attracted more and more attention and attention in recent years. Therefore, the application of shrinkage reducing agent may become a trend in the future. When the high-performance concrete excellent working performance and low shrinkage effect are realized by utilizing the high-efficiency water reducing agent and the reducing agent, both of the high-performance water reducing agent and the reducing agent will inevitably be used together in the concrete, Therefore, it is valuable and practical to study a series of compatibility problems which can be caused by co-use of high-efficiency water reducer and reducer. In this paper, the study of compatibility between high-efficiency water reducing agent and shrinkage reducing agent mainly affects the plasticizing effect of water reducing agent, the reducing effect of reducing agent and the influence on the mechanical properties of cement-based material. On the basis of this, the compatibility mechanism of polyacrylate water reducer and reducer was studied by UV-VIS spectrophotometer (UV), Zeta potential instrument, fluorescence spectrometer, Xray diffraction (XRD) and nitrogen adsorption analyzer. It is shown that the shrinkage reducing agent has no negative influence on the plasticizing effect of the polyacrylate water reducing agent, and even has an increasing effect on the fluidity of the net slurry; the shrinkage reducing agent of the polyacetal resin reducing agent and the reducing agent is enhanced with the reduction effect of the cement-based material; and the reducing agent 3 is used. The strength of the shrinkage-reducing agent (SRA-SBT) and the ether-like water-reducing agent (PC1) was 78.6% of the single-mixed PC1 group, lower than the strength of the reducing agent (SRA-G) and PC1, and the decrease of the strength of the mixed mortar with the ester polyacetal resin-reducing agent (PC2). It is less than 5%, and can improve the negative effect of the reducing agent on the mechanical properties of the mortar. The decreasing amplitude of the reducing agent and the water reducing agent in the same admixture with the water reducing agent is less than 7%, and the reducing agent is 5% higher than that of the water reducing agent. Therefore, the compatibility of PC1 with the reducing agent SRA-G is superior to that of the reducing agent SRA-SBT, and PC2 is compatible with the two reducing agents. The adsorption of cement-based materials on the two kinds of cement-based materials was studied by means of UV, zeta potential instrument and fluorescence spectrometer. The influence of the microstructure of water agent shows that the addition of shrinkage reducing agent reduces the surface zeta potential of the cement particle doped with the water reducing agent, but obviously decreases the electrostatic repulsion of the water reducing agent doped with the water reducing agent, increases the root mean square radius of the polyacetal resin and expands the PEO branched chain, which is beneficial to the increase. and the space position resistance potential energy is added, so that the polylactide can be appropriately increased. The effect of reducing agent on the evaporation rate, mortar and concrete mass loss in the presence of shrinkage reducing agent is studied. The shrinkage reduction effect of the cement-based material is realized mainly by reducing the surface tension of the solution, the shrinkage reducing agent can increase the viscosity of the solution and reduce the evaporation rate of the pore solution and the migration speed in the pores, the quality loss rate of the base material is reduced, By means of XRD and nitrogen adsorption, the effects of both the diffraction peak intensity, chemical bonding water content of calcium hydroxide and the development of cement stone pore structure in cement stone were studied. The effect of shrinkage reducing agent on hydration of cement is mainly shown as the decrease of chemical bonding water and calcium hydroxide content in cement stone at different age, and when the amount of shrinkage reducing agent is 3. 0%, it can make it more than 30nm in cement stone. the porosity is obviously increased, the porosity is obviously improved, and the above reasons are all
【學位授予單位】：重慶大學
【學位級別】：碩士
【學位授予年份】：2012
【分類號】：TU528.042
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