Effect of different exposure conditions on the self-healing capacity of engineered cementitious composites with crystalline admixture

In this study, the effect of different exposure conditions of ambient air, tap water, and seawater on two levels of crack widths in engineered cementitious composites (ECC) were investigated. Crystalline admixture (CA) was implemented in the ECC mix to promote self-healing capacity. Flexural testing on prism specimens (100 x 100 x 350 mm) was conducted to evaluate self-healing by recovering the stiffness in the specimens with crack widths below 200 mu m. Water permeability test was also carried out to assess the crack-filling capability of ECC disk specimens (100-mm diameter x 50-mm thickness) with single crack widths over 1 mm. Digital image correlation technique was used to monitor crack propagation patterns and crack widths. To analyze the microstructure of the healing products, X-ray diffraction test was conducted on groups of tap water and seawater exposures. Concluding results proved seawater to be a promising environmental condition for the self-healing process in ECC specimens incorporating CA, in terms of recovery of mechanical and transport properties. Brucite was found to be formed as the additional healing agent that promoted self-healing in this condition. These results can be applied for coastal concrete structures.

Automated summary

This study investigated the effects of different exposure conditions on crack widths in engineered cementitious composites (ECC) and found seawater to be a promising environment for the self-healing process in ECC specimens.