Abstract
This paper presents a new judging principle for corrosion testing of steel bars buried in reinforced concrete based on the self-magnetic flux leakage. The magnetic field signals decrease monotonously with the increase of the lift-off height of the magnetic sensor, which denotes the distance between the magnetic sensor and the specimen surface, for the undamaged area of the reinforcing steel bar while a reversal phenomenon appears for the corroded area. The lift-off height related to the reversal point will increase with the increase of the corrosion degree, and the corroded area could also be extracted from the magnetic field data. The competition between the demagnetizing field and the magnetic flux leakage from the corroded area could be used to explain the phenomena. The results indicate that the lift-off height related to the reversal point can be acted as the judging criterion for assessing the corrosion degree and the corrosion area of the reinforcing steel bar. The findings have extensive application prospect for detecting and evaluating the corrosion degree of reinforced concrete in engineering practice.