Investigation on early hydration behavior of cement based on piezoelectric sensor

Abstract

Cement is one of the most important building materials whose hydration behavior has great influence on quality of concrete. In this study, lead zirconate titanate (PZT) piezoelectric ceramic sensors were tailored and embedded into cement paste to monitor the early cement hydration reaction process in terms of the electromechanical impedance technique. The results show that the early hydration characteristics of the cement paste can be obtained by investigating the electromechanical impedance spectra of the PZT sensors. The impedance spectra of the PZT piezoelectric sensors exhibit distinguished variations with cement hydration reaction. The hydration index has been developed in terms of the impedance spectra variation by utilizing the piezoelectric sensors, and the early cement hydration reaction can be categorized as three periods based on this method – namely, the induction period in the initial 4 h of hydration, the accelerated period in 4–8 h of hydration and the late acceleration period in 8–12 h of hydration.