Effects of organosilane-modified polycarboxylate superplasticizer on the fluidity and hydration properties of cement paste

A series of organosilane-modified polycarboxylate (PCE) superplasticizer were synthesized, in which acrylic acid (AA) was partially or completely substituted by 3-(trimethoxysilyl) propyl methacrylate. This study mainly investigated their adsorption behavior, dispersing performance as well as their effects on cement hydration process. Results indicate that partially silylated PCEs exhibit larger adsorption than the reference PCE, decrease zeta potential of cement paste to a larger negative value and improve the fluidity properties of cement paste. The fluidity retention property of organosilane-modified PCEs is weaker, and the viscosity and the yield stress increase more steeply with time. Partially silylated PCEs can accelerate the cement hydration rate, and the mechanical strength is higher at 3 d due to accelerated hydration as well as improved pore structures.