The effect of carbon nanotube on self‐healing properties of engineered cementitious composites subjected to high temperatures

Abstract

AbstractThis study aims to examine the effect of carbon nanotubes (CNT) on the self‐healing performance of engineered cementitious composites (ECC) subjected to high temperatures. In ECC samples, CNT was used at 0%, 0.25%, 0.50%, and 0.75% by weight instead of cementitious materials. The cylindrical specimens containing CNT (Ø100 × 200 mm) were manufactured. The produced specimens were subjected to temperatures of 23 ± 2, 100, 200, 300, 400, 500, 600, 700, and 800°C after being cured at 23 ± 2°C for 28 days, and then, they left to cool at 23 ± 2°C for 1 day. Then, these specimens were preloaded at 70% of the ultimate splitting tensile strength to produce microcracks. Lastly, wetting–drying cycles were performed on ECCs for self‐healing. The ultrasonic pulse velocity (UPV), splitting tensile strength (fst), and rapid chloride permeability (RCPT) tests were applied to evaluate the self‐healing performance of specimens. Moreover, microstructural analyses such as scanning electron microscope (SEM), energy dispersive X‐ray spectroscopy (EDX), and X‐ray diffraction (XRD) were accomplished to identify the healing products formed in self‐healed cracks. According to the results of this study, the highest recovery rate of fst with 103.46% was attained from the ECC specimen containing 0.25% CNT exposed to 200°C.