Magnetic resonance eddy current testing imaging and non-destructive evaluation of rebar in concrete

This study, based on the principle of Magnetic Resonance Eddy Current Testing (MRECT), develops a small-diameter dual-coil resonant sensor for rebar detection in concrete. By increasing the aspect ratio of the magnetic core to optimize its geometry, high-resolution imaging of deeply embedded targets is achieved. Coupled with a multilayer perceptron (MLP) model, the system accurately predicts key geometric parameters. Experimental results demonstrate precise detection of rebars with diameters of 6–25 mm and embedded depths of 2–5 cm beneath a 5 cm concrete layer. The root mean square errors (RMSE) for diameter and depth prediction are 0.31 mm and 1.6 mm, respectively, with coefficients of determination (R²) reaching 0.99 and 0.98. Maximum relative errors are 7.68 % and 7.29 %, respectively. This approach provides an efficient and accurate solution for quantitative non-destructive testing of reinforcement in concrete structures, offering broad engineering prospects for construction quality assessment and structural health monitoring.