Degradation behaviors and damage model of the interface between ECC and concrete under sulfate wet-dry cycling

This study investigated the deterioration behaviors and damage model of the interface between ECC and concrete subjected to sulfate wet-dry cycling. The investigation considered how interface roughness and the frequency of sulfate dry and wet cycles influence the mechanical properties and durability of the ECC-concrete interface. The findings indicated that increased roughness significantly enhanced the durability of interface. Specifically, increasing the roughness substantially mitigates the rate of sulfate erosion, thereby improving the longevity of the interface. Conversely, a higher number of sulfate dry and wet cycles negatively affects interface durability, with an observable decrease in ultimate shear load correlating with the increase in cycle frequency. Importantly, a damage model was developed based on deterioration mechanism observed at the ECC-concrete interface during sulfate wet-dry cycling. This model effectively predicted interface behavior in erosive environments, aligning well with experimental results. Overall, this research offers valuable experimental data and theoretical insights that can aid in the strengthening of coastal concrete structures and promote wider application of ECC in reinforcing of concrete structures vulnerable to sulfate erosion. © 2025 Elsevier Ltd