不同黏土对掺减水剂水泥净浆流动度影响

目的 研究4种不同黏土对掺聚羧酸减水剂及萘系减水剂水泥净浆流动度的影响规律并从黏土的吸附性能角度探究其影响机理.方法 采用水泥净浆流动度试验方法比较了4种黏土对掺聚羧酸减水剂水泥净浆流动度的影响,通过TOC总有机碳测试仪测定了4种黏土对聚羧酸减水剂的吸附量.结果 4种黏土对水泥净浆流动度的影响差异较大,其中钙基蒙脱土和钠基蒙脱土的掺量为2％时,掺聚羧酸减水剂水泥净浆已基本没有流动度,掺萘系减水剂的水泥净浆流动度也有所下降,但降幅稍小,而伊利土和高岭土对掺减水剂水泥净浆流动度无明显负面影响；钙基蒙脱土和钠基蒙脱土对聚羧酸减水剂的吸附量较大,伊利土、高岭土对聚羧酸减水剂的吸附能力和水泥相当.结论蒙脱土对掺聚羧酸减水剂水泥净浆流动度负面影响极为严重,而伊利土和高岭土对掺减水剂水泥净浆基本没有负面影响.

Effect of Microfines on Fluidity of Cement Paste Mixed with Polycarboxylate Superplasticizer

Figure out the impact regularity and mechanism of four microfines on the fluidity of cement paste mixed with polycarboxylate superplasticizer from the perspective of adsorption properties of clay. Adopt the fluidity of cement paste as a performance index to compare the effect of four micro fines on the fluidity of ce- ment paste mixed with polycarboxylate superplasticizer and use TOC to determine the adsorption of four mi- crofines to polycarboxylate. Four microflnes have quite different influence on the fluidity of cement paste. The fluidity of cement paste added PC almost lost with Ca-Montmorillonite and Na-Montmorillonite incorpo- ration of 2%. We discover that the adsorption amount of PC on the two kinds of Montmorillonite is lager and the adsorption amount of PC on the Illite and Kaolin is equal with the cement. The results show that the fluidity of cement paste that added with PC lost much more than that of Montmorillonite, but Illite and Kao- lin have no negative effects on the fluidity of cement paste added water-reducer.