Effect of Different Kinds of Zinc (II) on Early Hydration of Calcium Aluminate Cement

Abstract

The early hydration of calcium aluminate cement (CAC) with different kinds of zinc (II), such as ZnSO4·7H2O, ZnO, Zn(NO3)2·6H2O and ZnCl2, was analyzed. Changes in consistency, setting time, hydration heat flow, hydration heat amount, ion concentration in solution, and hydration products were found upon the addition of different Zn2+. The water consumption of standard consistency of CAC is decreased with different Zn2+. Zn2+ can delay the initial hydration of CAC. The induction period of cement with Zn2+ is longer than that of CAC, especially the reaction time of the acceleration period is extended. Zn2+ can promote hydration hydrate of CAC at 24 h. The characteristic diffraction peaks of CA and CA2 in CAC with different Zn2+ are significantly reduced. It can inhibit the formation of CAH10 and promote the formation C3AH6 and AH3 in hydration products at 24 h.