Effect of moisture content and porosity on compressive strength of concrete during drying at 105 °C

Concrete structures can at times be exposed to temperatures of up to 105 degrees C. In this study, the compressive strength of concretes with different water-cement ratios during drying at 105 degrees C is measured. The results indicate that, with increasing moisture content, the compressive strength decreases initially and then increases. The effect of moisture content on compressive strength increases with the increasing porosity. In addition, the competitive effects of capillary pressure and microcracks on the evolution of the compressive strength during the drying process are discussed through mercury intrusion porosimetry (MIP) and the fluorescent epoxy impregnation method (FEIM). Finally, based on the strength-porosity model reported by Ryshkewitch, a strength-porosity-saturation model, which considers the effect of moisture content and porosity on the compressive strength, is proposed. (C) 2018 Elsevier Ltd. All rights reserved.