锈蚀与冻融耦合作用下再生混凝土与钢筋黏结性能梁式试验研究

为了研究锈蚀与冻融循环耦合作用下再生混凝土与钢筋的黏结滑移性能，以钢筋锈蚀率及冻融循环次数为变量，对耦合作用下的钢筋再生混凝土梁试件进行试验，分析其黏结滑移特征值变化规律，并与普通混凝土梁试件进行比较。根据试验结果建立钢筋再生混凝土黏结 滑移本构关系。结果表明：各组试件均发生纵筋拔出破坏；在钢筋锈蚀与冻融循环耦合作用下，冻融循环较钢筋锈蚀对黏结性能的影响更大；平均黏结应力-滑移曲线可大致分为线性上升段、非线性上升段、非线性下降段及残余段；再生混凝土试件的各黏结滑移特征值的波动幅度相对于普通混凝土的较大；在钢筋锈蚀与冻融循环耦合作用下，再生混凝土与钢筋间的化学胶着力要优于普通混凝土；普通混凝土的起始黏结应力与极限黏结应力的比值介于0.38~0.49之间，低于再生混凝土试件，再生混凝土抗滑移性能优于普通混凝土的。建立了考虑钢筋锈蚀与冻融循环耦合作用下的钢筋与再生混凝土黏结滑移本构关系，可为北方地区锈蚀率小于3%的再生混凝土梁黏结性能研究提供参考。

Beam test study on bond performance of recycledconcrete and steel bar under coupling effect of steel corrosion and freeze-thaw cycles

In order to study the bond-slip performance of recycled concrete and steel bars under the coupling effect of corroded steel bars and freeze-thaw cycles, the corrosion rate and the number of freeze-thaw cycles were used as parameters to perform beam test on beam specimens. The characteristic values of the bondslip were analyzed and compared with those of ordinary concrete. According to the test results, the bond-slip constitutive relationship of recycled concrete was established. The results show that the longitudinal reinforcement of all specimens are damaged by pulling out. Under the coupling effect of steel corrosion and freeze thaw cycles, the freeze thaw cycle has a greater impact on the bonding performance than steel bar corrosion. The average bond strength-slip curve can be roughly divided into linear ascending stage, nonlinear ascending stage, nonlinear decending stage and residual stage. The fluctuation range of the characteristic value of each bond-slip of recycled concrete is larger than that of ordinary concrete. Under the coupling effect of steel corrosion and freeze-thaw cycles, the chemical adhesion between recycled concrete and steel is better than that of ordinary concrete. The ratio of the initial bonding strength to the ultimate bonding strength of ordinary concrete is between 0.38~0.49, which is lower than that of recycled concrete, and the sliding resistance of recycled concrete is better than that of ordinary concrete. The constitutive relationship between the bond and slip of reinforced steel and recycled concrete under the coupling effect of reinforced steel corrosion and freeze-thaw cycles is established, which can provide reference for the bond performance analysis of recycled concrete beams with a corrosion rate of less than 3% in the north China.