基于压磁效应的锈蚀钢筋应力状态检测试验研究

钢筋锈蚀是严重威胁结构安全的耐久性问题,基于压磁效应,研究均匀锈蚀和坑蚀两种锈蚀钢筋的应力状态与压磁场变化的关系。首先,采用通电加速锈蚀方法进行钢筋均匀锈蚀和点蚀试验;然后,通过轴向拉伸静载试验和疲劳加载试验,分析锈蚀钢筋的压磁信号特征。试验结果显示,磁感强度与钢筋应力状态之间具有较好的对应关系,屈服阶段不同锈蚀率下的钢筋磁感强度曲线有较明显区别,疲劳荷载作用下锈蚀钢筋的法向残余磁感强度和磁滞回环面积均呈现疲劳三阶段变化规律,可进一步运用于钢筋应力状态的检测中。

Experimental study on stress detection of corroded steel bars based on piezomagnetic effect

Rebar corrosion has become a serious threat to structural safety. Based on piezomagnetic effect, it was focused on relationships between the stress states and magnetic signal changes under two kinds of corrosion forms (uniform corrosion and pitting corrosion). Firstly, the accelerated corrosion method was applied to obtain corroded steel bars. Uniaxial tension tests under static and cyclic loadings were carried out to analyze the evolution of magnetic signal. The test result indicates that the magnetic field intensity is corresponding to the stress state of the rebar. In the yield stage, the magnetic field intensity curves under different corrosion ratios are obviously different. It also shows that the residual magnetic intensity and the hysteresis loop area experience three steps of varieties, which can be further utilized in the stress detection of corroded rebar.