Experimental investigation on the bond-slip behavior between TRC-confined concrete and rebars after exposure to elevated temperatures

In this study, the bond-slip behavior between textile reinforced concrete (TRC)-confined concrete and rebars both at ambient temperature and after ISO 834 standard fire was investigated experimentally through pull-out tests. The failure modes, ultimate load, average ultimate bonding stress and energy consumption were obtained and discussed. Effects of rebar diameters (12 mm, 14 mm and 16 mm), bonding lengths (2.5d, 5d and 7.5d) and high-temperature exposure durations (30 min and 60 min) on the bonding behavior between TRC-confined concrete and rebars were examined emphatically. It was observed that the damage modes of specimens changed from pull-out failure at ambient temperature into splitting failure for both TRC-confined specimens and companion unconfined specimens exposed to high temperatures. The results obtained demonstrated that both the ultimate load and the average ultimate bonding stress can be significantly improved by the utilization of TRC jackets after 30 min exposure, and the increment of the average ultimate bonding stress can reach up to 90% as compared to those unconfined specimens. However, the enhancement of TRC jackets became unobvious after 60 min. Finally, based on test results and Prigogine's dissipative structure theory, the energy analysis of bond-slip curves was evaluated to verify the enhancement of TRC jackets quantitatively.