【作者】 丛立庆；

【导师】 范基骏；

【作者基本信息】 广西大学 ， 化学工艺， 2004， 硕士

【摘要】 本论文通过对当前国内外文献的查阅，综述了纳米二氧化硅的结构、性能及其各种制备方法，阐述了各种制备方法的优缺点。同时总结了纳米二氧化硅在橡胶制品、塑料制品、涂料和建筑材料等领域的应用情况。另外，还综述了当前国内外高性能水泥的种类和性能，以及我国水泥的发展现状，提出了固相制备纳米SiO₂及其复合水泥的研究方向。 纳米级SiO₂具有纳米材料特有的性质，如表面效应、小尺寸效应等，而且与水泥基材料发生水化反应，具有高的活性。本论文探讨了这些纳米技术理论与水泥水化理论的有机结合，提出“纳米诱导水化效应”。论述制备纳米SiO₂复合水泥的可行性。 用TEM、SEM、TG／DTA、XRD和IR等测试方法，研究了共沸蒸馏和直接干燥方法处理纳米SiO₂粉末对其性能的影响。结果表明，共沸蒸馏法能有效的脱除SiO₂凝胶中的水，防止干燥过程中颗粒间硬团聚的形成。所制得的纳米SiO₂粉体颗粒为无定型态，粒径在30～40nm间。 在分别研究了纳米级SiO₂和硅灰的活性对水泥基材料的改性后，将它们复合，作为高活性的掺合料，加入水泥基材料中，探索对水泥基材料的复合改性效应。对复合改性后的水泥硬化浆体进行宏观力学 广西大学硕士学位论文纳米5102的合成及其对水泥基材料性能影响的研究性能测试、抗渗性能测试和孔隙率的测试，发现复合改性后的水泥硬化浆体其抗压强度、抗渗性能和孔隙率都得到明显改善。用OTA、XRD、SEM分析了水泥基材料的组成、显微结构，结果表明，纳米级5 1 02比硅灰具有高的活性，二者复合活性更佳，它们改性的水泥硬化浆体显微结构致密，C一S一H凝胶交织成致密的网状结构，缺陷显著降低;尚且，纳米 5 1 02对水泥硬化浆体中的氢氧化钙相有显著的吸收作用。 本论文经过以上对复合改性水泥性能的研究，探讨了纳米5 1 02与水泥浆体作用的机理，提出了用固相反应法制备纳米二氧化硅的新思路和纳米诱导水化效应的新概念。更多还原

【Abstract】 The characteristic, structure, preparation methods of nano-SiO2, merits and demerits of these methods are summarized in the thesis after looking up the literatures at home and abroad. Its application in the fields of rubber, plastics and building materials are also recounted. In addition, developing situation in our country, the kinds and properties for high-performence OPC(Ordinary Portland cement) at home and abroad are also summed up. Then the methods of solid-phase preparation of nano-SiO2 and study orientation of nano-SiO2 composite cement are posed.The properties of nanometer materials, for instance, surface-effect, small-size effect and so on, were presented in nano-SiO2. And high activities of reacting chemically with cement matrix existed in nano-SiO2. In this thesis, the effective combination nanometer technology theories with cement hydrate theories are approched and the effect of nanometer inducement hydrate was firstly put forward. The feasibility of preparation nano-SiO2 composite cement was discussed here.With the use of test methods of TEM, SEM, TG/DTA, XRD and IR, the influences on the properties in azeotropic distillation and direct dry during preparing nano- SiO2 powder are studied. The results show that thewater in silica gel can be effectively removed by azeotropic distillation and the formation of hard agglomerates in the drying process is prevented. The particles of nano-SiO2 powder are amorphous and average particle diameters are in the range of 20 to 30 nm.After studying the activities of nano-SiO2 and silica fume individully, they are mixed into highly active additives and added to ordinary Portland cement for approaching composite modified effect. After testing the properties of macroscopic mechanics, anti-penetrability and porosity in modified hardening slurry, compressive strength, anti-penetrability and porosity are obviously improved and the activities of nano-SiO2 powder are higher than these of silica fume. When mixing them, these activities are even excellent. There are dense microstructure, thick interwoven net-C-S-H and fewer defects in modified hardening slurry. The nano-SiO2 powder can evidently absorb the Ca (OH) 2 phases in the slurry.According to the above-mentioned studies, the reactive mechanism of nano-SiO2 in the slurry is approched. New thinking of preparing nano-SiO2 with the help of method of solid phase reaction and up-to-date concept of nanometer inducement hydrate effect are put forward here.更多还原