In this study, the push-out experiment with load reversal and up to four load half-cycles was conducted on concrete-filled steel tube (CFST) members to investigate parameters affecting the natural bond capacity (chemical adhesion, micro-locking, and macro-locking) and bond-slip curves before and after heat-induced damage. Variables under study included the exposure temperature, length-to-diameter ratio of steel tube (L/D), diameter to thickness ratio of steel tube (D/t), grade of cementitious materials, and type of concrete (pumice lightweight concrete and normal concrete). The results showed that exposure to heat often had a negative effect on chemical cohesion and friction between the steel tube and concrete core. In this regard, after exposure to 200, 400, and 600 °C, the bond capacity of the lightweight CFST specimens respectively remained relatively unchanged (negligible increase or decrease) and declined by 84 and 94% compared with that at the ambient temperature. An increase in parameter L/D due to an increase in length and a decrease in diameter led to a drop and a rise in the bond capacity, respectively. As the D/t ratio increased (due to a rise in D or a drop in t) in the lightweight CFST specimens, the bond capacity declined after exposure to all the target temperatures. In addition, lightweight concrete specimens with a smaller cement grade showed greater bond capacities compared with the corresponding columns with a higher cement grade for most exposure temperatures. Moreover, the bond capacity of the specimen with normal concrete was significantly higher than the corresponding specimen with lightweight concrete (around 8 times) for the exposure temperature of 600 °C. By comparing half-cycles 1 and 3 of CFST specimens, the share of macro-locking was obtained as 12 and 34% for 600 °C. The initial stiffness and energy absorption of the specimens with the lightweight concrete experience a significant drop after exposure to 600 °C compared with the ambient
