Experimental study on bond-slip behavior of steel reinforced high strength concrete after high temperature

In order to study the bond-slip behavior between shape steel and high strength concrete after high temperature, a total of 17 steel reinforced high strength concrete (SRHC) specimens were designed for push out test. Concrete strength, constant temperature and anchorage length were considered to research their influences on ultimate bond strength and residual bond strength of SRHC. The load-slip curves with the characteristic point parameters were gotten, and the formulas to calculate the ultimate bond strength and the residual bond strength were gained by regression using the results of this experiment and previous studies. The influence of constant temperature on the invalidation mechanism was researched in details. Test results show that the shapes of load-slip curves at the loading ends and free ends are similar, and the loading ends slip earlier than the free ends. The ultimate bond strength and residual bond strength of SRHC decrease first and then recover partly with the constant temperature increasing. The bond strength is proportional to the concrete strength, and the bond strength is proportional to the anchoring length when the constant temperature is low, while the opposite situation occurs when the constant temperature is high. The interface elastic shear strength decreases first and then recovers partly with the increasing of constant temperature. The bond damage of specimens with lower constant temperature developes earlier and faster than the specimens with higher constant temperature. The energy dissipation capacity of the bonding interface is proportional to the constant temperature.