Magnetic flux leakage signal analysis of
corroded reinforcing bar in concrete
1. School of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, China; 2. T. Y. Lin International Engineering Consulting（China） Co., Ltd., Chongqing 401120, China; 3. Guizhou Expressway Group Co., Ltd., Guiyang, Guizhou 550000, China
Abstract：The magnetic flux leakage (MFL) technology was applied to detect the corrosion of steel bars inside the concrete. Based on the magnetic dipole model, the corroded steel bar was numerically analyzed. The specimens were corroded，and the MFL signals were acquired and analyzed. The MFL field distribution was calculated by the proposed calculation theory based on the magnetic dipole model. The Bxx curve of magnetic induction intensity and the Kxx curve of magnetic induction intensity gradient along the specimen longitudinal direction were obtained. The results of simulation and experiment show that the steel corrosion degree can be semiquantitatively evaluated by the peak value of the Bxx curve.The area of steel corrosion can be quantitatively measured according to the zero point spacing of Kxx curve. The effects of stirrups and concrete cover thickness on the detection of steel corrosion can be negligible.
2019, Vol. 40 
