中文摘要：

分别用水泥及水化硅酸钙研究了硫酸盐对掺聚羧酸减水剂水泥浆体流动性及其吸附量的影响,发现Na2SO4会显著降低聚羧酸减水剂的分散性及其在水化硅酸钙表面的吸附量,而CaSO4·2H2O对聚羧酸减水剂分散性及吸附量的影响较小。通过一系列微观测试手段对硫酸盐降低聚羧酸减水剂分散性及吸附量的原因进行了分析,认为其主要原因是由于聚羧酸减水剂与硫酸盐之间存在着竞争吸附、硫酸盐会使聚羧酸减水剂聚集体增大、硫酸盐增大了水化硅酸钙Ca2＋溶出浓度。实际工程中,需严格控制早强剂Na2SO4的掺量,以保证掺聚羧酸减水剂的水泥浆体维持较高的分散性。

英文摘要：

The effect of sulfate on the fluidity of cement paste with superplasticizer and the adsorption capacity of superplasticizer by calcium silicate hydrates were investigated. The results show that Na2SO4 has a pronounced negative effect on the dispersity and adsorption of superplasticizer. However, the effect of CaSO4·2H2O on the dispersity and adsorption capacity of superplasticizer is slight. It is indicated that the competitive adsorption between sulfate and superplasticizer, the aggregation behavior of superplasticizer and the increase of Ca2＋ dissolved are due to the effect of sulfate on the dispersity of superplasticizer. It is suggested that the dosage of Na2SO4 as an early strength agent should be strictly controlled in practical engineering in order to ensure the cement paste maintain with a high dispersity.