聚合物改性机制砂的制备及其对水泥基复合材料的影响机理

Cement-based materials have advantages such as high compressive strength, good durable performance , low price and so on. However, its application has been limited due to its low flexural strength and tensile strength. According to the concrete principle , the principle of polymer modification, and the toughening mechanism of polymer materials, the polymer-grafting modified manufactured sand is prepared to improve the flexural and tensile properties of concrete. Then, the structure and properties of polymer-grafting modified manufactured sand can be regulated by changing the types and quantity of functional groups on the surface of manufactured sand, the types of macromolecular monomers, the length of polymer chains, solvents and coupling agents. Moreover, the effect of polymer-grafting modified manufactured sand on the concrete mixture ratio,structure and properties of concrete is studied. In this project, the mechanism of action of polymer grafting modified manufactured and its influence principle on the flexural strength and tensile strength of concrete will be investigated thoroughly. These studies will explore a new realm of improving the performance of concrete. The project not only possesses great academic value, but also has great economic value.

水泥基复合材料具有抗压强度高、耐久性能好、价格低廉等优点，但其低抗折、抗拉强度限制了应用范围。本项目根据混凝土和高分子改性材料的设计和合成原理，以及高分子材料增韧理论，制备出聚合物接枝改性机制砂，以提高混凝土的抗折、抗拉性能。通过改变机制砂表面官能团种类和数量、偶联剂、聚合物单体、高分子链长、溶剂等调节聚合物接枝改性机制砂的结构和性质；研究聚合物接枝改性机制砂对混凝土配合比、结构以及性能的影响；探讨聚合物接枝改性机制砂在混凝土中的作用机理，着重研究其对混凝土抗折、抗拉强度的影响原理。该研究将开拓提高混凝土性能的研究新领域，不但具有很强的学术价值，而且具有很大的经济价值！

随着建筑用河砂需求量的增加及河砂开采的限制，机制砂因具有经济环保的作用将成为河砂的有效替代品。机制砂是一种混凝土理想的细骨料，然而目.前机制砂应用在混凝土中会减小混凝土的流动性，增加需水量，导致混凝土容易出现较大地自收缩和脆性骨折，极大的影响混凝土的抗折强度和抗压强度。.近年来，无机粒子与聚合物通过化学键相结合进行表面修饰取得了快速发展。在这里，机制砂粒子通过聚合物进行修饰，减弱机制砂粒子对混凝土流动性及.需水量的影响，从而改善工作性和提高抗折强度。机制砂粒子通过化学键与高分子进行键合，使得机制砂粒子与混凝土浆体之间的界面结合力增强。