Self‐healing of engineered cementitious composites under reversed and sustained loading conditions

Abstract

AbstractThe present study investigates the effects of reversed and sustained flexural loading cycles on the repeatability of self‐healing in engineered cementitious composites (ECC). The experimental work is designed to test three cases of normal (REF), reverse (REV), and reverse‐sustained (RES) loading and three different exposure conditions of tap water, sea water, and open air. A total of 27 prism specimens (100 × 100 × 350 mm) were fabricated, and a four‐point bending test was used for flexural load application at different stages and to further measure the recovery in mechanical properties. The research is proposed to elaborate on the positive/negative impact of compression cycle on the self‐healing of cracks. Ultrasonic pulse velocity (UPV) test was carried out before and after each loading and the wave travel time was compared as an indicator of healing efficiency. To monitor crack propagation patterns and crack widths, digital image correlation (DIC) technique was used. To further analyze the mineralogy and microstructure of the healing products, X‐ray diffraction (XRD) test was conducted on two groups of tap water and sea water exposures. Concluding results proved that sea water and tap water are suitable environments for autogenous self‐healing process. Furthermore, reverse loading cycles were demonstrated to impact the self‐healing results and should be considered for repeatable self‐healing evaluations.