Effect Of Clay Mineral Composition On Polycarboxylate Superplasticizer Dispersibility

During engineering applications, mud attached on the aggregate can reduce water dispersion performance of polycarboxylate superplasticizer. Clay is a significant component in mud and it is the most significant component of negative impact on the dispersion performance polycarboxylate superplasticizer. Clays adsorbing polycarboxylate superplasticizer and mixing water is the main reasons that clays can reduce the fluidity of cement paste, mortar and concrete mixed polycarboxylate superplasticizer and different kinds of clay have diferent degrees of influnence on the performance of polycarboxylate superplasticizer.Nowadays most of research focus on the effect of clay from different regions or different size on the workability and mechanical properties of concrete,these can not get a suitable conclusion, Lacking of systematic analysis of the negative effects of clay. This article mainly studied the effect of the main clay mineral of mud on the properties of polycarboxylate superplasticizer from the perspective of single mineral clay and simulated clay.Selecting of montmorillonite(sodium), illite, kaolin soil as the basic object of study, we prepared four areas of simulated clay, basing on the statistical analysis of literature.The influence rules of clay mineral composition on the dispersion performance of polycarboxylate superplasticizer was studied,through the fluidity tests of cement paste mixed with PC of different kinds of single mineral clay and different areas of simulated clay. The results show that the negative effect of montmorillonite of clay mineral composition on polycarboxylate superplasticizer is most significant.There is different negative effect among four areas of simulated clay on polycarboxylate superplasticizer due to the content of montmorillonite and the relative content changes of ilite and kaolin. The content of montmorillonite is the dominant factor of the influence of simulated clay on the dispersion performance of polycarboxylate superplasticizerThe adsorption characteristics of the clay minerals was learned through the perspective of the adsorption of single mineral clay and simulated clay to water and polycarboxylate superplasticizer, hoping it can eliminate the negative effect of clay mineral on the properties of polycarboxylate superplasticizer through adding extra polycarboxylate superplasticizer. The results show that the adsorption of montmorillonite to polycarboxylate superplasticizer is much larger than other single mineral clay. Water absorption performance of simulated clay of Southwest-C and Central-C,which content more of montmorillonite, is strong,however, polycarboxylate superplasticizer absorption performance of them is smaller than simulated clay of Northeast-C and east-C,which content less of montmorillonite.It can not eliminate the negative effect of clay mineral using adding extra water in engineering application. Engineering cost goal should be taken into consideration when using adding extra polycarboxylate superplasticizer to eliminate the negative effect of clay mineral.Adopting the method of regression analysis, through the linear regression analysis of negative effect of single mineral clay and simulated clay on the fluidity of cement paste mixed with PC and absorption performance of them, using SPSS software, Corresponding regression equation was concluded.It can be used to analyze and predict the negative effect degree of clay mineral composition on polycarboxylate superplasticizer.