可再分散聚合物对水泥水化反应热释放规律及性能影响研究.doc

可再分散聚合物对水泥水化反应热的 释放规律与性能影响研究 摘要 可再分散聚合物对水泥水化热的释放和水化产物会产生显著的影响，对改善水泥浆体性能具有重要意义。在本论文工作中，选取聚乙烯醋酸乙烯酯可再分散乳胶粉作为水泥浆体的改性聚合物，通过测定聚合物水泥浆体的水化热，利用X射线衍射（XRD）（IR））C-S-H凝胶生成时间延缓，生成量低于相同龄期纯水泥的C-S-H生成量，即延缓了C3S的水化。EVA能明显延迟Ca(OH)2生成时间，降低其含量且低于相同水化时间的纯水泥浆体，并且随胶粉掺量的增加其含量越来越低，相同掺量乳胶粉的聚合物改性水泥浆体水化7天时期Ca(OH)2含量多于3天的含量。这是因为EVA与Ca(OH)2发生了反应，有乙酸钙和聚乙烯醇生成。与纯水泥相比，水化早期的 Ca(OH)2降低了，反应生成的乙酸钙具有促进C3A水化的作用，所以刚开始水化时有一小的放热峰。随着聚灰比的提高，聚合物改性水泥浆体的抗折强度先提高，然后呈下降趋势，说明存在一个最佳的掺量范围。 关键词: 水泥浆体 ；聚乙烯醋酸乙烯脂乳胶粉；水化热；水化产物 Study on Effect of Redispersible Polymer on Liberation Discipline of Heat of Hydration and Property of Cement Wang Longlong (Anhui Institute of Architecture Industry) Abstract Redispersible polymer can have a significant effect on the heat of hydration and hydration products of cement when this type of polymer is added in cement paste. This effect means a lot to the improvement of properties of cement paste. In this article, Ethylene and Vinyl Acetate Copolymer（EVA）was chosen as the modified polymer of cement paste. Through measuring the heat of hydration, the mechanism of affecting the heat of hydration were investigated by means of XRD 、IR and SEM. The results show that the polymer powder can postpone the peak time of heat of hydration, lower the peak temperature and temperature rise of fresh cement paste. But different types of powder have different degrees of effect on the hydration heat. The results of XRD show that polymer powder was added in cement paste to make formation time of C-S-H gel delay. Besides, the formation content is lower than that of the pure cement paste within same hydration age. Namely, the polymer powder can postpone the hydration process of C3S. Besides EVA can significantly delay the formation time of Ca(OH)2 , reducing its content. The content is lower than that of pure cement paste of the same hydration time, and is also reducing more and more with the increasing content of powder. The content of Ca(OH)2 within hydration ti