Investigating the failure process of concrete under the coupled actions between sulfate attack and drying-wetting cycles by using X-ray CT

X-ray CT was implemented to investigate the failure process of concrete material under the coupled actions between sulfate attack and drying-wetting cycles. Macroscopic performance of concrete and microcosmic variation of concrete pores under sulfate attack combined with drying-wetting cycles were experimentally investigated, and then the correlation between them was analyzed by using grey incidence theory. The results showed that the coupled actions from sulfate attack and drying-wetting cycles intensified the damage of interior structure of concrete pores. The higher concentration of salt solution was, the more serious damage of pore structure was. Drying-wetting cycles coarsened the pores of concrete specimens so that the sulfate was more prone to enter the interior of concrete, thereby accelerate the failure of concrete material.