Zhigang Zhang

ID No: 136 Abstract: Cracks are inevitable for concrete infrastructures during their service life. The presence of cracks reduces the mechanical properties and bring potential safety hazard to infrastructure. In this study, the influence of self-healing on the ECC’s (Engineered cementitious composite) tensile properties was investigated. ECC is a new kind of HPFRCC, featuring high strain capacity of 3-5%, accompanying by sequential multiple micro-cracks development, while maintaining tight crack width (about 20 μm in this study). The dog-bone shape specimens used in the tensile test were pre-loaded to the tensile strain levels of 1%, 2%, 3%, and 4%. After that, to achieve micro-cracks’ self-healing, the pre-loaded cracked specimens were immersed in the water, undergoing wet-dry cycles. The self-healed specimens were then reloaded under tension. The results show that ECC can still have high tensile strain capacity of 4% and more than 90% of ultimate tensile strength after healing. The first cracking strength recovers to 50% of original cracking strength, and the stiffness recovery ratio of cracked-specimens ranges from 58% to 92%. With the tensile mechanical properties recovery caused by its self-healing behavior, ECC can be a resilient material for civil infrastructures.