Experimental study on performance deterioration of internally cured pavement concrete under sulfate-wet-dry erosion cycles

To enhance the performance of cement concrete pavements in saline soil areas, this study investigated the damage patterns of flexural and compressive strengths in pavement concrete internally cured with super absorbent polymer (SAP) under sulfate-dry-wet erosion cycles. The deterioration of chloride ion penetration resistance under different numbers of environmental erosion cycles was then examined. Furthermore, the characteristics of hydration products were analyzed based on infrared spectroscopy (FTIR) test, revealing the mechanism by which internal curing influences the performance of pavement concrete under environmental actions. The results indicate that after 90 cycles of sulfate-dry-wet erosion, the internal curing group exhibits higher flexural and compressive strengths than the control group, with maximum increases of 29.6 % and 12.8 %, respectively, while the chloride migration coefficient is reduced by 19.46 %. At the same SAP content, the specimens subjected to natural curing exhibits superior effectiveness compared to those with sealed curing using an anti-cracking coating. The incorporation of SAP is found to provide buffer space for the expansion of erosive products, thereby mitigating the extent of concrete damage during the middle and late stages of sulfate erosion.