硅酸盐水泥干缩特性曲线的建立与研究

Establish of Drying Shrinkage Characteristics Curve of Portland Cement and Research

通过水泥砂浆干缩特性的分析,建立硅酸盐水泥干缩特性曲线,讨论化学外加剂对硅酸盐水泥干缩特性的影响。研究表明:硅酸盐水泥干缩特性曲线变化规律呈“W”形,第1峰谷形成的主导因素是物理作用,第2个峰谷形成的主导因素可能是C—S—H凝胶等水化产物的化学作用。减水剂使第1峰谷出现的时间提前,促进了早期的干缩行为;单掺减缩剂对砂浆干缩历程的影响不大,对砂浆25 d的减缩效果较弱;减水剂与减缩剂的复合显著削弱第1峰谷和第2峰谷,叠加效应表现出各组分单掺情况下所不具有的显著减缩功能。

Based on the analysis of drying shrinkage characteristics, the influences of chemical admixtures on the drying shrinkage characteristics were studied in this paper. The results show that the drying shrinkage characteristics curve acted as ＂W＂, the first peak was formed because of physical mechanism, while the second peak was formed for chemical mechanism. The first peak was accelerated by water-reducing agent, the early shrinkage behavior was promoted; the drying shrinkage process was not markedly changed by shrinkage-reducing agent, and the shrinkage of 25 days was not reduced obviously; Both of the peaks were weakened remarkably by the compound of water-reducer agent and shrinkage-reduclng agent, which didn＇t exist in each member solely.