Self-healing of engineered cementitious composites at simulated summer conditions

Self-healing of engineered cementitious composites (ECC) subjected to a cyclic drying and wetting regime simulated summer outdoor environment was investigated in this paper. Uniaxial tension tests were used to generate multiple cracks in ECC specimens deformed to varying tensile strains. To quantify self-healing, resonant frequency measurements were conducted throughout drying-wetting cycles followed by tensile testing of self-healing ECC specimens. It was found that through self-healing the resonant frequency of ECC can recover 81 % to 90 % of initial values while showing a distinct rebound in stiffness of cracked ECC after self-healing. For specimens pre-loaded to high levels of strain between 2 % and 3 %, the tensile strain after self-healing can recover from 1.8% to 2.2%. Also, the effects of temperature during cyclic regime can lead to an increase in the ultimate strength of the material while slightly decreasing the strain-hardening capacity of ECC due to further hydration of unreacted cement and fly ash.