聚羧酸系减水剂侧链结构对水泥塑化效果的影响

Effects of polycarboxylate-type water-reducer side chains on plasticizing effect of cement

通过不同分子量聚乙二醇(PEG)复配,合成含有不同长度的聚氧乙烯基侧链,同时带有羧酸基团、磺酸基团的聚羧酸系减水剂。着重讨论减水剂在水泥表面的吸附性,不同长度的侧链在摩尔比不同时对水泥塑化效果的影响。实验结果表明,聚羧酸共聚物合成时将不同长度侧链的聚乙二醇调整为n(PEG1500)∶n(PEG1000)∶n(PEG800)=1∶2∶2时,可以获得最佳的塑化效果。当聚羧酸系减水剂掺量为0.6%,W/C为0.29时,水泥初始净浆流动度和2 h经时流动度达到297mm和270mm。

Polycarboxylate-type water-reducers with carboxyl acid groups, sulfonic groups and polyoxyethylene side chains in different length were synthesized through mixing polyethylene glycol （PEG）with different molecular weight. Emphasis is laid on discussion about absorbability of the water reducer on the surface of cement and influences of the side-chains with different length in different mol ratio on plasticizing effect of cement. The experimental t＇esuhs show that the optimal plasticizing effect can be obtained by adjusting the mol ratio of polyethylene glycol（PEG} with different length of side-chains when synthesize polyocarboxy acid copolymer i.e. n（PEG1500）：n（ PEG1000）：n （PEG800）=1：2：2. The initial cement paste fluidity and cement paste fluidity after 2 h. is up to 297 mm and 270 mm respectively when the content of polycarboxylate-type water-reducer is 0,6% and W/C is 0.29.