Influences of Corrosion Degree and Uniformity on Bond Strength and Cracking Pattern of Cement Mortar and PVA-ECC

Abstract

Engineered cementitious composites (ECCs), which have a strain-hardening behavior under tension, is widely used for repairing and retrofitting reinforced concrete structures. In such applications, the performance of the bond between the ECC and corroded rebar is critical for the service life prediction of the repaired structures. In this study, the cracking patterns and bond behavior of polyvinyl alcohol (PVA) ECCs (PVA-ECCs) and cement mortar with uniform and nonuniform corroded steel rebars were studied. It was found that the uniform corrosion–induced cracks were randomly distributed, while the nonuniform corrosion–induced cracks were concentrated perpendicular to the most corroded side. The bond strength of PVA-ECC and mortar specimens was independent of the corrosion method. The bond strength of PVA-ECC and mortar specimens both showed a trend of increasing first and then decreasing with the development of corrosion rate. The threshold corrosion rate for mortar specimens was 0.125%, and the threshold corrosion rate of PVA-ECC specimens was 0.922%.