Effects of Adsorption Group and Molecular Weight of Viscosity-Modifying Admixtures on the Properties of Cement Paste

AbstractTo explore the potential application of high-performance viscosity-modifying admixtures (VMAs) is of great importance. In this work, the effects of the adsorption group and molecular weight of VMAs on the properties of fresh cement paste were studied. A series of copolymers having similar molecular weights but different adsorption groups (carboxyl, sulfonic, and quaternary ammonium groups) were compared for the first time. A series of copolymers having the same chemical structure but different molecular weights were also compared. The adsorption, fluidity, bleeding, and rheological properties of the fresh cement paste mixed with different copolymers were tested. The results show that the copolymer, having stronger adsorption group (carboxyl group) and higher molecular weight, could decrease the bleeding and fluidity while enhancing the stability of the fresh cement paste more effectively. The study may help explore ideal materials for the design and preparation of synthetic polymer VMAs.