The damage mechanism and failure prediction of concrete under wetting–drying cycles with sodium sulfate solution

Abstract

This study aims to investigate the damage mechanism and predict the failure time of concrete subjected to wetting and drying (WD) cycles in a sodium sulfate solution. To explore the growth rules and the growth rates of gypsum, the reaction-rate constant calculation formula of gypsum is proposed based on theories of chemical reaction kinetics. Subsequently, the formulae of the volume fractions of mirabilite and gypsum in the pore under each WD cycle are proposed and used to calculate the macroscopical tensile stress to determine the WD cycle number that the concrete can sustain. Finally, the reliability of the proposed model is verified by an indoor experiment. In addition, a new damage type of concrete, induced by filling-damaging cycles, is also found during the experiment. These findings can be used for evaluating the damage of concrete that is subjected to cyclic WD in sodium sulfate solution.