冻融环境下钢筋与再生混凝土粘结性能及界面损伤研究

为了揭示冻融环境下钢筋与再生混凝土的粘结破坏机理及其影响因素,对冻融环境下钢筋与再生混凝土的界面粘结试验进行数据统计后,利用几何损伤理论建立粘结退化模型,引入指数函数对损伤滑移曲线进行拟合后,建立冻融环境下钢筋与再生混凝土的粘结滑移损伤本构关系;并从能量损伤的角度分析界面粘结耗能,定义粘结能量因子以量化不同冻融循环次数...

Bond Performance and Interface Damage Between Reinforcement and Recycled Concrete under Freezing-thawing Environment

On the basis of statistical data of interfacial bonding test between steel bar and recycled concrete under freezing-thawing environment, we built a model of bonding degradation in line with the gemetric damage theory. By fitting the bond strength-slip curve using exponential function, we established a bond-slip damage constitutive relation between steel bar and recycled concrete in freezing-thawing environment. Moreover, we analyzed the interfacial bonding energy consumption by defining the bonding energy factor to quantify the changes of interfacial bonding performance under different freeze-thaw cycles. Results revealed that the bonding energy of specimen with zero recycled aggregate was close to that with 100% of recycled aggregate, both larger than those with 30% and 60% of recycled aggregate. Given the same replacement ratio of recycled aggregate, the bonding energy factor declined with the proceeding of freezing-thawing cycles, indicating evident reduction of energy consumption ability; at the same cycle, the bonding energy factor first increased while then dropped with the augment of recycled aggregate ratio; when the replacement ratio of recycled aggregate was 30%, the energy consumption ability reached the optimum. The research findings revealed the failure mechanism and influencing factors for the interface between steel bar and recycled concrete in freeze-thaw environment, helped improving the basic theoretical system of recycled concrete, and offered reference for the application of recycled concrete in practical engineering.