Zhao Jun, Yin Lu, Li Xiaopeng, Yue Xinjie
School of Civil Engineering, Zhengzhou University, Zhengzhou 450001, China.
Materials (Basel). 2023 Jul 5;16(13):4836. doi: 10.3390/ma16134836.
Plain bars with a diameter of 10 mm are widely used in reinforced concrete buildings, and the bond behavior between the bars and concrete has an essential effect on the seismic performance of concrete structures. Thus, to assess the safety of old buildings and repaired buildings with normal concrete, it was necessary to further investigate the bond performance of the plain bars in the concrete. The bonding tests under monotonic and reversed cyclic loading were carried out on the specimens reinforced with plain bars, and the influences of concrete grade and embedment length on the bond behavior were taken into consideration. The results indicate the maximum bond stress under reversed cyclic loading is less than that under monotonic loading, and this is the same for corresponding slip for the same test parameters. The concrete compressive strength positively affects the maximum bond stress, whereas the embedment length has a negative effect. Based on the elasticity analysis and test data fitting, the expressions of bond stress at characteristic points on the bond stress-slip curves were carried out. Consequently, the bond stress-slip model was established, which could be applied to calculate the bond stress-slip relationships under monotonic and reversed cyclic loading. By comparison between the test curves and proposed model, a good agreement is observed, which indicates that the proposed model can be used to predict the bond stress-slip curve of plain bars in concrete.
直径为10毫米的光圆钢筋在钢筋混凝土建筑中广泛应用，钢筋与混凝土之间的粘结性能对混凝土结构的抗震性能有着至关重要的影响。因此，为评估普通混凝土旧建筑和修复建筑的安全性，有必要进一步研究光圆钢筋在混凝土中的粘结性能。对光圆钢筋加固的试件进行了单调加载和反复循环加载下的粘结试验，并考虑了混凝土等级和锚固长度对粘结性能的影响。结果表明，反复循环加载下的最大粘结应力小于单调加载下的最大粘结应力，对于相同的试验参数，相应的滑移情况也是如此。混凝土抗压强度对最大粘结应力有积极影响，而锚固长度则有负面影响。基于弹性分析和试验数据拟合，得出了粘结应力-滑移曲线上特征点的粘结应力表达式。进而建立了粘结应力-滑移模型，该模型可用于计算单调加载和反复循环加载下的粘结应力-滑移关系。通过试验曲线与所提模型的对比，发现两者吻合良好，这表明所提模型可用于预测混凝土中光圆钢筋的粘结应力-滑移曲线。
