1.Guangxi university;2.Tongji university
The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan)
In order to study the bond-slip performance between concrete and steel rebar after different cooling ways, 39 pull-out tests of reinforced concrete specimens after exposure to high temperature and the splitting tensile strength tests of concrete under natural cooling way were carried out. The effect of high temperature and different cooling ways on peak bond stress and peak slip are discussed. The calculation equations between peak bond stress, peak slip and temperatures are established, and the full curve equation of bond slip considering initial temperature damage is also proposed. Based on the theoretical model, the theoretical bond strength after natural cooling is calculated. The results show that: with the increase of temperature, the peak bond stress decreases linearly, the maximum reduction for 500℃ reaches to 80.5% ,and the peak slip first decreases and then increases after the same cooling way, and the cooling way has little effect on these parameters; the theoretical damage bond slip curves is consistent with the test curves; the bond strength calculated by the theoretical model well agree with the test value.