聚羧酸序列结构对水泥浆体早期性能的影响

Impact of polycarboxylate superplasticizer with different sequence structures on early properties of cement paste

通过测试不同序列结构的聚羧酸(PCE)在水泥浆体中的吸附特性,对水泥浆体流动度、水化放热速率、水化产物生成量、水泥水化产物形貌等的影响,揭示了PCE序列结构对水泥浆体早期性能的影响规律。结果表明:与无规PCE相比,嵌段PCE吸附量较大,吸附速率较快,因此,初始分散性较好,流动度损失较大。水化放热速率表明:掺嵌段PCE的水泥水化诱导期缩短、水化主放热峰出现得更早。XRD、SEM结果进一步表明:嵌段PCE加速了钙矾石和C-S-H凝胶的生成,同时促进了C_3A和C_3S的水化过程。

The influence of polycarboxylate （PCE） with different sequence structures on the early hydration of cement,for instance, adsorption amount onto fresh cement paste,fluidity,rate of heat of hydration,content of hydration products and morphology were investigated systematically. The results indicated that compared with PCE with random distribution,block PCE adsorbed faster on cement particle surfaces with a larger adsorption amount,subsequent the better initial dispersity and the faster loss of fluidity. The heat flow rate showed that block PCE shortened the dormant period of the ＇hydration with earlier main hydration peak. The results from XRD and SEM illustrated that block PCE accelerated the formation of ettringite and C-S-H gel, promoting both the hydration of C3A and C3S.