Rapid detection of embedded steel bars using scanning eddy current thermography

To rapidly visualize steel reinforcements in existing reinforced concrete (RC) structures is crucial prior to undertaking strengthening and repair operations. This study proposes a novel non-destructive evaluation (NDE) method, scanning eddy current thermography (ECT), for visualization of steel bars embedded in RC structures. A scanning ECT system was specifically developed, aiming at detecting steel bars with varying diameters, from 6 mm to 36 mm, in two RC specimens. The results demonstrated that the scanning ECT system is capable of visualizing steel bars with diameters exceeding 6 mm at a cover depth of 20 mm. The heating was conducted using a pre-defined path, with a duration of 1 minute. A multi-physics numerical simulation was performed, which agreed well with the experimental results of thermal response. This study highlights the potential of ECT as a NDE technique for the inspection of steel reinforcement in RC structures.