锈蚀钢筋截面分布特征及轴向拉伸力学性能

采用半浸泡通电加速锈蚀法获得平均锈蚀率为0%～18%的钢筋,应用三维扫描的实物反求技术获得精确的锈蚀钢筋截面积数据,研究得到了平均锈蚀率与最大截面锈蚀率的关系,统计建立了锈蚀钢筋截面积概率分布模型;通过轴向拉伸试验研究锈蚀钢筋力学性能退化原因,定量分析锈蚀率与钢筋各力学特征值损失率的关系.结果表明:锈蚀钢筋实际材料性能未发生改变,其名义屈服强度、名义极限强度由钢筋最小残余截面积决定;钢筋变形与钢筋残余截面积分布有关,与平均锈蚀率及最大截面锈蚀率的相关程度较低;锈蚀钢筋本构关系仍可采用未锈蚀钢筋的本构关系,并可通过残余截面积概率分布模型来反映锈蚀对钢筋力学性能的影响.

Cross Section Distribution Characteristics and Tensile Behavior of Corroded Reinforcing Steel Bars

The steel bars with corrosion degree of 0%18% were collected from accelerated corrosion method by impressing current. Reverse engineering techniques were then applied to obtain accurate cross sectional area of steel bars. Based on the data, the relationship between average and maximum cross section loss ratio was studied and the probability distribution model of cross sectional area was established statistically. Axial tensile tests for steel bars were carried out to investigate the deterioration of mechanical properties due to corrosion. Furthermore, the relationship between mechanical characteristics loss ratio and cross section loss ratio was analyzed. The results show that the nominal yield strength and ultimate strength are dependent on the minimum residual cross sectional area, and that the deformation is related to the distribution of residual cross sectional area, but little to the average or maximum cross section loss ratio. The actual material properties of corroded bars are not changed, which means the effect of corrosion on the mechanical performances of steel bars can be considered by reducing the residual cross sectional area and the constitutive model of uncorroded bars is still applicable.