Ultrasonic monitoring of capillary porosity evolution and strength gain in hydrating cement pastes

Abstract

An ultrasonic test procedure for determining the capillary porosity in hydrating cement paste is presented. The response of hydrating cement paste through setting is monitored using horizontally polarized shear waves (SH). Changes in the ultrasonic signal through setting are related with changes in the porosity and stiffness of an equivalent water- filled poroelastic material, which provides identical acoustic impedance. The porosity obtained from the ultrasonic measurements, is identical to capillary porosity obtained from the conventional themo-gravimetric analysis. A unique relationship between capillary porosity and compressive strength is established for hydrating cement pastes. © RILEM 2013.