Experimental Study on Bond Behavior Between HRB600 Steel Bars and High-strength Concrete

To investigate the bond behaviors between HRB600 steel bars and high-strength concrete, the central pull-out tests of 48 specimens were carried out in this research. The influences of different parameters on the bond behaviors between HRB600 steel bars and high-strength concrete were compared and analyzed. The main design parameters were concrete strength, anchorage length, thickness of concrete cover, stirrup ratio and steel fiber content.The formula of ultimate bond strength and bond-slip constitutive relation between the HRB600 steel bars and high-strength concrete were established and the applicability of the current standard to anchorage design of HRB600 steel bars and high-strength concrete was evaluated based on the test results. The test results show that the change rules of bond strength between HRB600 steel bars and high strength concrete with different design parameters are basically consistent with that of ordinary reinforced concrete, which demonstrates that the bond strength increases with the increase of concrete strength, thickness of concrete cover and stirrup ratio. After adding the steel fiber in the high-strength concrete, the bond strength increases with the increase of steel fiber content. The bond failure of specimens with HRB600 steel bars and high-strength concrete shows less ductility compared with that of specimens with ordinary steel bars and concrete, and the ductility can be obviously improved by adding steel fiber or deploying stirrups in high-strength concrete.