掺梳形减水剂水泥浆体早期水化产物形貌研究

Investigation on early hydrates of cement pastes superplasticized by comb-type copolymer

为揭示梳形减水剂对水泥早期水化的影响规律,指导工程应用,通过SEM分析,研究了掺用3种典型结构的梳形减水剂的水泥浆体早期水化产物形貌及其电子特征数据。结果表明,梳形减水剂加速了水泥早期水化反应,且丙烯酸类、马来酸类共聚物分别促进了AFt、AFm的形成。因此,梳形减水剂品种对水泥早期水化和混凝土工程性能具有较大影响,应根据使用要求合理选用,必要时与缓凝剂、引气剂或消泡剂复合使用。

The aim of this paper is to find out regularity of comb-type water reducers effect on early hydration of cement and to guide engineering applications of comb-type water reducers.Microstructures of early hydrates of cement superplasticized by three typical polycarboxylates were observed by SEM,and the electronic characteristic data of cement hydrates were analyzed.It is found that comb-type water reducers can accelerate hydration rate of cement minerals.Moreover,acrylic acid based copolymer promotes formation of ettringite,and maleic anhydrite based copolymer speeds up formation of monosulfoaluminate.Therefore,early hydration of cement and engineering properties of concrete are dominated by the kind of comb-type water reducers.Suitable choice should be made according to application requirements of concrete engineering,and modification should be done by blending retarders,air entraining agent or defoaming agent if needed.