Scale-linking model of self-healing and stiffness recovery in Engineered Cementitious Composites (ECC)

Micro-crack damage in Engineered Cementitious Composites (ECC) has demonstrated self-repairing capacity when exposed to wetting-drying cycles. Previous studies qualitatively relate composite stiffness recovery to crack width. There is a need to develop a more quantitative understanding of the relationship between the magnitude of self-healing and imposed strain in ECC. An analytic model that links the stiffness recovery of a single crack in ECC (meso-scale) to that of an ECC loaded to multiple micro-crack damage (macro-scale) was investigated in this study. The objective of this research is to develop this theoretical scale-linking model and validate it with experimental data. It is found that the proposed scale-linking model successfully predicted the composite stiffness recovery at any strain, based on known macro-scale crack patterns and meso-scale self-healing behavior. It is concluded that the new model captures the essence of self-healing behavior in ECC. The model clarifies the pathway for designing ECC with robust self-healing behavior.