Effects of Organosilane-modified PCE on the Fluidity and Hydration Properties of Cement-Fly Ash Composite Binder

Abstract

Effects of organosilane-modified PCE (OS-PCE) on the fluidity and the hydration properties of cement-fly ash (FA) composite binder were systematically analyzed. The experimental results show that OS-PCE possesses respectively 36.98% and 36.67% higher saturated adsorption amount on cement and FA, in comparison with ordinary PCE, and can contribute to higher fluidity of cement-FA composite binder. The addition of OS-PCE retards hydration process of cement-FA composite binder proportionally with the dosage of OS-PCE, but promotes the hydration kinetics of the composite binder. The reactivity enhancement is attributed to the well-dispersed FA by OS-PCE, which provides more nucleation sites for the reaction of heterogeneous C-S-H and enhances the contact with water to react with CH forming pozzolanic C-S-H. Well-distributed hydration products are exhibited in the hardened binder added with OS-PCE, with a large number of hydrated gels uniformly fill in the pores and gaps, which improves the compaction of the hardened structure.

Keywords

cement / fly ash / organosilane-modified PCE / fluidity / hydration properties