Monitoring Steel Rebar Corrosion-induced Cracking in ECC Cover byDOFS

Abstract

Steel corrosion is the main threat to the durability of concrete structures, and the cracking or spalling of concrete cover caused by the expansion of corroded steel can largely accelerate the deterioration process. Engineered cementitious composites (ECCs), as one type of high-performance fiber-reinforced cementitious composites with high tensile ductility and excellent ability of crack width control, have a great potential to be able to improve the durability of structures under corrosive environment. Nevertheless, corrosion of steel rebar may still happen in ECC if aggressive agents depassivate the rebar; therefore, the relationship between the corrosion level and cracking degree in ECC cover is essential for accurately estimating the corrosion condition as well as service life of steel reinforced ECC structures. This study investigates the cracking process of ECC under accelerated steel corrosion implemented by impressed current, during which the distributed optical fiber sensors (DOFS) were employed both on the steel rebar surface and surface of ECC specimens to monitor the internal strain and surface strain generated by the corrosion expansion. The results show that DOFS provide an effective non-destructive tool for detecting the corrosion of steel rebar at early stage when the surface cracks in ECC are not visible.

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