反复荷载作用下钢筋与纤维混凝土黏结性能试验研究

为研究添加钢纤维和钢碳混杂纤维对于钢筋与混凝土在反复荷载作用下黏结性能影响，进行了48个混凝土轴心受力钢筋短锚试件在单调、等幅反复荷载以及变幅反复荷载作用下黏结性能的试验研究。结果表明：添加纤维可在一定程度上改善钢筋与混凝土间的黏结性能；黏结性能的退化在等幅反复荷载作用下主要体现在黏结应力-滑移滞回曲线峰值黏结应力的退化；在变幅反复荷载作用下主要表现为黏结强度、卸载刚度、摩阻力的不断降低，以及卸载至零时残余滑移量的不断增长；影响黏结退化的主要因素是前期的最大控制位移水平，低控制位移水平下的加载循环对高控制位移水平下的黏结性能影响较小，并给出了合理的退化机理解释。

Study on bond performance between steel and fiber reinforced concrete under cyclic loading

Experiment on bond performance between reinforcing steel and fiber reinforced concrete under monotonic and cyclic loading was carried out. Meanwhile steel fiber or hybrid of steel and carbon fiber were added to concrete to study the effect of the fibers. There were 48 specimens of short anchorage altogether, 12 for monotonic pull out test including 3 specimens of plain concrete, 3 specimens of steel fiber reinforced concrete and 3 with added hybrid of steel and carbon fiber and 36 for cyclic loading. Test results indicate that steel fiber and hybrid of steel and carbon fiber can increase peak bond stress and improve bond ductility. Under constant amplitude cyclic loading the degradation of bond performance mainly embodies in the degradation of peak bond stress. Under variable amplitude cyclic loading, the peak bond stress, stiffness of unloading branch and frictional bond stress decrease gradually. Meanwhile, the residual slip increases when loading is unloaded completely. The main influencing factor that affects the bond performance is historical maximum controlling slip and the smaller controlling displacement at early stage has less influence on bond performance under larger controlling displacement. Finally according to the theoretical analysis and testing results, the formative reasons of three typical hysteresis curves under different controlling slip are explained.