HRB600级钢筋与高强混凝土的黏结性能试验研究

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

为进一步了解HRB600级钢筋与高强混凝土之间的黏结性能,进行48个试件的中心拔出试验,对比分析不同参数对于HRB600级钢筋与高强混凝土黏结性能的影响.主要变化参数为混凝土强度、锚固长度、保护层厚度、配箍率和钢纤维掺量.在试验基础上,确立HRB600级钢筋与高强混凝土的极限黏结强度公式和黏结滑移本构关系,评价分析现行规范对HRB600级钢筋高强混凝土锚固设计的适用性.试验结果表明:HRB600级钢筋与高强混凝土的极限黏结强度与普通钢筋混凝土极限黏结强度随各影响因素的变化规律基本一致,即极限黏结强度随混凝土强度、保护层厚度、横向配筋率的提高而提高;掺入钢纤维后,极限黏结强度随钢纤维掺量的增多而提高;HRB600级钢筋与高强混凝土黏结破坏时脆性增强,延性相对较差,在高强混凝土中掺入钢纤维或配置一定量的箍筋可以显著改善其延性.

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.