考虑均匀/非均匀锈蚀特征参数的钢筋力学与变形性能

开展了45个混凝土试件中135根加速锈蚀钢筋的单轴拉伸试验，分别建立了均匀/非均匀锈蚀特征参数与锈蚀钢筋的力学性能参数和变形性能参数之间的定量关系，进而提出了基于均匀/非均匀锈蚀特征参数的锈蚀钢筋应力应变关系模型。结果表明：锈蚀钢筋的力学和变形性能参数与锈蚀特征参数之间的相关性较大，随着质量锈蚀率、最大截面锈蚀率和最大锈蚀深度相对值的增加呈现线性减小趋势，而随着最小剩余截面积相对值和面积点蚀因子的增大呈现线性增大趋势；随着钢筋锈蚀程度的增加，锈蚀钢筋的屈服平台会出现明显退化现象，当质量锈蚀率、最大截面锈蚀率和最大锈蚀深度相对值分别大于20%、60%和40%左右或最小剩余截面积相对值和面积点蚀因子分别小于40%和60%左右时，屈服平台基本消失；轻度锈蚀钢筋可以利用均匀和非均匀锈蚀特征参数来描述应力应变关系曲线，而重度锈蚀钢筋采用非均匀锈蚀特征参数来描述应力应变关系曲线更合理。

Mechanical and deformation properties of steel bars based on uniform/non-uniform corrosion characteristic parameters

Based on the uniaxial tensile tests of 135 accelerated corrosion steel bars from 45 concrete specimens, quantitative relationships between uniform and non-uniform corrosion characteristic parameters of reinforcement bars and the mechanical and deformation parameters were established. Then the stress-strain model of corroded steel bars based on the above characteristic parameters was proposed. The results show that the correlations between the mechanical/deformation property parameters and the corrosion characteristic parameters of corroded steel bars are relatively high. The above mechanical/deformation property parameters of corroded steel bars decrease linearly with increase of the mass loss ratio, the maximum cross-sectional loss ratio and the relative maximum corrosion depth, while increase with the relative minimum residual cross-sectional area and the area pitting factor. Moreover, the yielding platform of the corroded steel bars deteriorates obviously with increase of degree of corrosion. When the mass loss ratio, the maximum cross-sectional loss ratio and the relative maximum corrosion depth is greater than 20%, 60% and 40%, respectively, or the relative minimum residual cross-sectional area and the area pitting factor is less than 40% and 60%, respectively, the yielding platform of corroded steel bars almost disappears. Both uniform and non-uniform corrosion characteristic parameters are suitable to describe the stress-strain curves of steel bars with slight corrosion, while the non-uniform corrosion characteristic parameters are more suitable for steel bars with severe corrosion.