Multiple-scale investigations on self-healing induced mechanical property recovery of ECC

The self-healing behavior of Engineered Cementitious Composites (ECC) has attracted much research in the past decade. Nonetheless, very few study attempted to reveal the underlying mechanism of self-healing induced mechanical recovery of pre-damaged ECC. In this paper, the influence of self-healing on the material properties of ECC was investigated on multiple length scales. Plausible underlying mechanisms of mechanical properties recovery of ECC are proposed. The results show obvious regaining of tensile/flexural properties of pre-damaged ECC at macro-scale due to self-healing. At the meso-scale, self-healing leads to fiber bridging strength recovery to about the same level as that of virgin specimens. At the micro-scale, self-healing is found associated with recovery of frictional bond strength between the fiber and matrix. However, chemical bond recovery appears to be absent. The regaining in fiber/matrix interfacial friction results in the recovery of fiber bridging capacity, which forms the root cause for recovery of the mechanical properties of self-healed ECC.