Experimental investigation on uneven corrosion characteristics and mechanical behaviors of rebar in pre‐cracked <scp>ECC</scp> under sustained loading

Abstract This paper is aimed at investigating the corrosion behavior of steel rebars in pre‐cracked engineered cementitious composite (ECC) under sustained loading, simulating the service conditions of coastal underground structures exposed to chloride enriched environments. Experiments combined electrochemical corrosion (5%–15% mass loss) with mechanical loading controlled by strain (800–1200 με). Results indicate that the dense microstructure of ECC significantly inhibits chloride penetration, reducing the effective corrosion ratio to 45.4% of the theoretical value under low loads (800 με). However, higher sustained loads (1200 με) and corrosion levels exacerbate localized corrosion at crack regions, increasing the effective corrosion ratio to 95.8%. 3D scanning revealed load‐dependent corrosion patterns, transitioning from uniform to multi‐peak distributions. The findings highlight that sustained loads and crack‐induced stress concentrations critically govern corrosion non‐uniformity and mechanical performance. This paper provides a foundation for designing durable ECC‐RC hybrid structures in aggressive environments.