Chloride penetration of concrete exposed to dry-wet cycle with various dry-wet ratios and temperature

Abstract

Numerous factors influence the concrete performance in dry-wet cycle environment, with dry-wet ratio and temperature being particularly significant. In this paper, the effect of dry-wet ratios (1:3, 1:1, and 3:1) on the chloride corrosion resistance of concrete was studied, and the variable test temperature and constant test temperature were implemented in the dry-wet cycle. The deterioration law of chloride corrosion resistance of concrete was investigated, and the microstructure, phase composition, and pore structure were examined. The results showed that the deterioration degree of concrete performance was intensified by a higher dry-wet ratio. Compared with D1W3 (the dry-wet ratio is 1:3), the compressive strength, splitting tensile strength, flexural strength, mass, and relative dynamic elasticity modulus (RDEM) of D3W1 (the dry-wet ratio is 3:1) exposed to 72 dry-wet cycles decreased by 11.05%, 19.40%, 8.33%, 1.09%, and 6.14%, respectively, while the peak chloride content and erosion depth increased by 40.98% and 22.75%. Compared to the dry-wet cycle with constant temperature, the cumulative damage caused by the dry-wet cycle with variable temperature was greater, resulting in more severe deterioration of concrete performance. Variable temperature accelerated the diffusion rate and penetration depth of chloride ions. The peak chloride content and erosion depth of D1W3 were 27.08% and 18.44% higher than those of control group after 72 dry-wet cycles. Microscopic analysis confirmed that higher dry-wet ratio and variable temperature cycles accelerated the decay of mechanical strength and the decline of chloride erosion resistance.