Multiple-scaled investigations on mechanical properties of medium-early- strength PVA-ECC with recycled tire crumb rubber incorporated

In recent years, significant attention has been directed toward advancing medium-early-strength engineered cementitious composites (MES-ECC), reflecting their growing importance in construction research. However, limited research has explored the fundamental principles governing the mechanical behavior of MES-ECC. This study systematically investigates the multi-scale effects of crumb rubber (CR) content and curing duration on the mechanical performance of MES-ECC. The results showed that the compressive strength and tensile strength of MES-ECC of 3 days at the macro-scale are reached more than 60 % of 28 days. The incorporation of CR in MES-ECC produced a characteristic trade-off between strength and ductility. While compressive strength showed measurable reduction, the MES-ECC demonstrated significantly enhanced deformation capacity through featuring greater the number of cracks and reduced crack widths at macroscopic scale. The pseudo-strain-hardening (PSH) value decreased with extended curing ages, correlating directly with the observed ductility reduction in MES-ECC. Notably, incorporating CR enhances the ductility and multiple cracking behavior of MES-ECC, successfully counteracting the detrimental impacts of reduced deformability.