Flexural repairing of highly corroded reinforced concrete structures with engineered cementitious composites (ECC)

Corrosion of steel rebars is a principal factor leading to a reduced load-bearing capacity of structural components, necessitating appropriate repairing. The exceptional tensile properties, toughness, and crack control of Engineered Cementitious Composite (ECC) provide significant advantages in the repair of concrete components with corroded steel rebar. The present study investigates the effectiveness of ECC in repairing the flexural capacity of concrete structures with highly corroded steel rebars. The interfacial bond performance between ECC and concrete was assessed through bond flexural tests, while direct tension tests on reduced cross-sectional steel rebars surrounded by ECC evaluated the recovery of load-bearing capacity and repair effectiveness across different bond lengths. Bending tests on ECC repaired beams were also conducted to further explore their repair efficiency. The experimental findings revealed that a bond length of 5.5D ensures effective load transfer, and consequently the ultimate load recovery rate of corroded steel rebar specimens repaired with ECC exceeds 96%, with some specimens achieving full recovery. Experimental results also demonstrated the efficacy of ECC in repairing concrete structures with corroded steel rebars, achieving notable recovery rates that are nearly equivalent to or exceed 90% in both yield and ultimate strengths. A theoretical analysis was conducted to calculate the load-bearing capacity of ECC repaired specimens, explaining the differences in load-bearing capacities compared to uncorroded concrete beams.