EXPERIMENTAL RESEARCH OF HIGH TEMPERATURE EFFECT ON BONDING PERFORMANCES BETWEEN STEEL BARS AND CONCRETE

Central pulling test on 44 cubic specimens of conventional concrete and recycled concrete (the replacement ratio of coarse aggregate is 100%) were subjected to high temperatures. Tthe damage laws of bonding performances of the steel bars and concrete after and in high temperatures and the characteristics of bond-slip (τ-s) relation curves were studied.The experimental results showed that after and in high temperatures, the ultimate bond strength of steel bars and concrete decreased with increase of temperatures, and the ultimate slip values increased with increase of temperatures.According to the changing characteristics of the bond-slip curves between steel bars and concrete, the bond-slip failure process of steel bars and concrete in high temperaturs could be divided into five stages to analyze the bond performance damage.By setting damage variables and using regression analysis methods, to establish the τ-s relation equations between steel bars and concrete after and in high temperatures. And through the calculation of test deviation, the calculation results were in good agreements with the test results.