硫酸盐对掺聚羧酸减水剂水泥浆体流变性的影响

Effect of Sulfate on Rheological Properties of Cement Paste with Polycarboxylate-Type Superplasticizer

研究了6种硫酸盐对掺聚羧酸减水剂水泥浆体的Marsh时间、剪切应力及表观黏度的影响.通过微观手段分析硫酸根离子对聚羧酸减水剂吸附量的影响.结果表明:碱金属硫酸盐会显著降低掺聚羧酸减水剂水泥浆体的分散性,而难溶性硫酸盐对掺聚羧酸减水剂水泥浆体分散性的影响较小.硫酸根离子大量存在时,聚羧酸减水剂的表观吸附量及无效吸附量增加,聚羧酸减水剂的分散性能降低,浆体絮凝结构数量及强度增大.

Effects of different sulfates on Marsh time,shear stress,and apparent viscosity of cement paste with polycarboxylate-type（PC）superplasticizer were investigated.Through a series of micro measurements,it was indicated that with abundant SO2-4in the cement paste,the adsorption amount of PC superplasticizer increased.The results show that sulfates with alkali ions（such as Na2SO4 and K2SO4）have a pronounced negative effect on the dispersity of PC superplasticizer,while the effect of indissolvable sulfate（such as CaSO4·2H2O）on the dispersity of PC superplasticizer is slight.Large amount of SO2-4contributed to the declining dispersity of PC superplasticizer,and the increasing amount and strength of flocculent structure in cement paste.