Research progress on polycarboxylate based superplasticizers with tolerance to clays - A review

Polycarboxylate ether/ester (PCE) superplasticizers are widely used due to their molecular structural designability, low dosage and high efficiency. However, their high sensitivity and strong interactions with clays in concrete reduce their dispersion and water-reduction capability, which can affect the performance of concrete seriously. This paper reviews the interactions between PCE superplasticizers and clays before and after calcination, and the enhancement techniques of the resistance of PCE superplasticizers to clays, and points out their advantages and disadvantages. Reduction in the number of active sites of clays by the addition of small molecular polymers as sacrificial agents can decrease the physical and chemical adsorption of PCEs. Introduction of functional groups into PCE can restrain its intercalation by clays. Apparently, more clays robust PCE superplasticizers can be achieved via molecular design. This review can provide a direction for the further design and development of PCE superplasticizers.