Chloride Ion Transport in Concrete Subjected to Sustained Compressive Stress Under Different Dry-Wet Ratios

Existing studies on chloride ion transport in concrete under compressive load had rarely incorporated the influence of the dry-wet time ratio, even though this ratio was a key factor affecting chloride penetration in coastal concrete structures subjected to periodic drying-wetting cycles. This study was therefore motivated to fill this gap and to provide more reliable theoretical support for the durability assessment of such engineering structures. A series of accelerated chloride ion penetration experiments was conducted on concrete under compressive load with different dry-wet time ratios. The effects of the dry-wet time ratio, compressive stress level, and exposure environment on chloride ion transport in concrete were analyzed. A chloride ion diffusion coefficient model that accounted for both the dry-wet time ratio and the compressive stress level was then established and validated. The results showed that the enhancing effect of the dry-wet time ratio on chloride ion transport became significant under relatively high compressive stress. When the dry-wet time ratio was 7:1, the convection zone depths of concrete specimens under no stress and compressive stress were both 5 mm. Moreover, when the compressive stress level was 0.5 times the compressive strength and the dry-wet time ratio was 7:1, the chloride concentration of the specimens increased by an average of 756.4% compared with that under natural immersion.