Investigations on the shear performance degradation of ECC-NC grooved interface under salt freeze-thaw cycles

This study aims to clarify the mechanical behavior of engineered cementitious composite (ECC)normal concrete (NC) grooved interface under salt freeze-thaw cycles. A comprehensive analysis was conducted to study the effects of the cycle number, interface agent, and ECC strength on the interface shear performance. The results showed that, compared with specimens in room temperature conditions, after 200 cycles, the shear strength and shear stiffness of all specimens decreased by no less than 37.8 % and 52.7 %, respectively. Moreover, using different interface agents or increasing ECC strength improved the interface salt freeze-thaw resistance significantly. Among all specimens using interface agents, fly ash had the best-enhancing effect on the interface shear performance. Additionally, considering interface area corrosion and degradation of material properties, a damage model was established. Based on the damage model, an equation for calculating the interface shear capacity was proposed, providing a valuable reference for the engineering application of ECC reinforcement in extreme environments.