含不同支链聚羧酸系减水剂的应用性能研究

摘要

合成了一系列不同支链和相近聚合度的聚羧酸系减水剂,系统研究了其对水泥净浆流动度和流动度损失、凝结时间、新拌砂浆的泌水率和硬化砂浆力学强度的影响.结果表明,长短支链结合的聚羧酸系减水剂分散性能最佳,单一长支链的次之,单一短支链的最差:长支链比例越高,净浆流动度损失越大,浆体缓凝效果越弱,新拌砂浆泌水率越小;掺减水剂硬化砂浆的力学强度变化规律与其分散性能的变化规律一致.%A series of polycarboxylate-type superplastieizers (PC), possessing almost the same degree of polymerization and different side chains,were synthesized, and the effect of side chains on the performance of PC in cement system was systematically studied. The system studied its influence to the fluidity,fluidity loss, setting time of the cement paste, bleeding rate of fresh mortar and mechanical strength of hardened mortar. The results show that,PC containing both short side chains and long side chains has the best dispersibility, while PC containing only long side chains has a better dispersibility than PC containing only short side chains. A higher long side chain ratio on PC leads to a larger fluidity loss, a retardation of setting time and a lower bleeding rate. In addition,the changing rule of mechanical strength of hardened mortar produced by PC is in accordance with the changing rule of dispersing property of PC in cement pastes.