基于金属磁记忆的钢筋混凝土结构锈蚀检测

Corrosion detection of reinforced concrete structures based on metal magnetic memory

针对钢筋混凝土结构锈蚀检测难的问题,采用金属磁记忆(Metal Magnetic Memory)无损检测技术,开展了钢筋混凝土锈蚀检测试验,探索其内部钢筋锈蚀与漏磁信号之间的特征关系。首先对10片试验梁采用电化学加速锈蚀,然后对锈蚀后的试验梁进行漏磁信号采集,最后开展破坏性试验来验证钢筋锈蚀情况。结果表明:钢筋锈蚀区域用漏磁信号切向分量Bx曲线交点或其梯度dBx/dx曲线判断;当漏磁探头提离高度Z=2 cm时,漏磁信号切向分量极值增量ΔBx_i与钢筋锈蚀深度h呈明显线性相关性;钢筋断裂可以通过漏磁信号切向分量Bx极值或其梯度dBx/dx极值相对上一个阶段不再增加来进行判别。并通过COMSOL建模验证了试验梁锈蚀检测试验结果的可靠性。

In view of the problem of corrosion detection of reinforced concrete structure,the Metal Magnetic Memory(MMM)nondestructive testing technology is used to carry out the experiment about the corrosion detection of reinforced concrete structure to explore the relationship between corrosion of rebar and magnetic flux leakage signals.In the experiment,firstly the ten test beams were rusted by the electrochemical accelerated method.Then the magnetic flux leakage signal was collected from the rusted test beams.Finally,destructive test is carried out to verify the corrosion of rebar.Research shows both the magnetic leakage signal tangential component Bx distribution curve and its gradient d Bx/dx distribution curve can identify areas of corrosion.When the magnetic memory signal acquisition probe lifting height is Z=2 cm,there is obviously linear correlation between the peak value of the tangential component of the magnetic flux leakage signal and the corrosion depth of the rebar.When the maximum value of the tangential component of the magnetic leakage signal or its gradient is invariant or decreased compared with its last stage,the rebar is ruptured.COMSOL modeling is used to verify the reliability of test results of corrosion of steel bars in concrete structure.