Experimental evaluation of concrete-reinforcement bond: Bond failure mechanisms after exposure to elevated temperatures

This work presents an experimental assessment of the bond failure mechanisms after exposure to elevated temperatures. The interaction between concrete residual mechanical properties was shown to determine which failure mechanism takes place in each situation. Exposure to 200 ºC positively affects bond strength; however, as the temperature increases above this range, the bond strength progressively deteriorates. Bar slip was affected only by the bond failure mechanism change between C30 concrete and deformed rebars at 200 ºC. The absence of a standard specimen was highlighted as a challenge to understanding bond failure mechanisms. •Bar slip at ultimate bond strength is not affected by temperature.•Higher compressive strength is more influenced by the cover/diameter ratio.•Compressive and tensile strengths cause a change in bond failure mechanism.•The fib Model Code bond-slip model is not fit to describe the postfire situation.•Specimens’ geometric configuration affects the bond failure mechanism.