The Polycarboxylate-based Superplasticizers Modified with thickening agents: the performance and Influece on Cement Hydration

Keywords: Polycarboxylate-based superplasticizer, thickening agent, water-reducing ratio, compressive strength, cement hydration. Abstract. The application of effective superplasticizer is helpful to improve the working performance and durability of concrete. In our work, several high performance polycarboxylate-based superplasticizers were prepared by modifying the commercial products with two types of thickening agents. Their dispersion ability for cement was investigated by fluidity and bleeding tests, while their influences on mortar working performance were evaluated based on the water-reducing ratio and the compressive strength experiments. The hydrated products of cement mortar were characterized by SEM and DSC-TGA technologies as well. Results indicated that three types of superplasticizers, including PCA, PCA-1 and PCA-2, exhibited good cement compatibility and water-reducing effects. These superplasticizers delayed the initial period of cement hydration, and made the hydration products of mortar develop into the more compact and ordered structures, consequently leading to the higher compressive strength.