Selfhealing Processes and Products of Engineered Cementitious Composites Materials

Abstract:

The growth processes of selfhealing products on 15 μm,30 μm,and 50 μm cracks as well as on fiber surfaces were displayed by means of ESEM.The chemical characterizations of healing products were reported by applying many advanced research technologies such as EDS,TEM,XRD and FTIR.These results suggest that further hydration of cementitious materials and the formation of CSH gel and CaCO3 crystals are the main reasons for the selfhealing phenomena.CSH is the main selfhealing product for crack widths of 15 μm,and CSH and CaCO3are the main selfhealing products for crack widths of 30 μm.Selfhealing products couldn’t fill in the crack widths of 50 μm within observation period.At the microlevel,cracks below 30 μm in width can be almost totally healed.Meanwhile,PVA fibers with hydrophilic nature in ECC provide nucleation sites for healing products that may aid in the selfhealing of ECC.