聚羧酸减水剂在水泥和泥土表面的吸附行为

采用有机碳测定仪研究了水泥、泥土和水体系中聚羧酸减水剂吸附量与吸附时间、减水剂浓度、体系温度的关系。同时,对减水剂吸附模型和吸附热进行了分析,探讨了聚羧酸减水剂在水泥、泥土颗粒表面的吸附特性。结果表明:水泥和泥土对聚羧酸减水剂的吸附量随时间延长不断增加,最后达到平衡,同时,泥土比水泥对减水剂的吸附量要大,泥土的掺入量为0.5%就会大大降低水泥净浆的流动度;聚羧酸减水剂的吸附基本符合Langmuir等温吸附模型,水泥和泥土对减水剂的饱和吸附量分别为3.7mg/g和10.1mg/g;水泥和泥土对聚羧酸减水剂的吸附量随温度的增大而减小,其吸附是一个放热过程。

Adsorption Characteristics of Polycarboxylate Superplasticizer on Surface of Cement and Clay

By using TOC,this paper studies the relationship between adsorption amount of polycarboxylate superplasticizer(PC) and adsorption time,concentration and temperature of the system in the cement,clay and water system.At the same time,adsorption model and adsorption heat are analyzed,and the adsorption characteristics of PC are investigated.The results showed that: the adsorption of PC on cement and clay increases with time elapsing,and adsorption amount finally reaches equilibrium,while adsorption amount of PC on clay is larger than that on cement,the fluidity of cement paste added PC decreases obviously with clay incorporation of 0.5%;PC adsorption model belongs to Langmuir adsorption isotherm model,saturated adsorption of PC on cement and clay is 3.7 mg/g and 10.1 mg/g,respectively;the adsorption of PC on cement and clay decreases with temperature,the adsorption is an exothermic process.