Improved magnetic-based apparatus enables non-destructive and high sensitive steel-bar corrosion detection.

• An improved non-destructive magnetic-based steel bar corrosion detection with simple structure and high accuracy. • Equivalent numerical model to quantify the corrosion degrees and impacts of frame internal structural parameters. • Sensitivity coefficient changes linearly with the diameter of steel rods. • Increase in frame width and foot length are beneficial to growth of sensitivity coefficient. • Adding extra calibration magnetic circuits leads to reduction in sensitivity coefficient. Steel-bar corrosion can not only induce corrosion cracking, but also cause the bearing capacity decline of concrete structures. This contribution reported an improved magnetic-based steel bar corrosion detection apparatus with simple structure and high accuracy. Accelerated corrosion tests on steel rebar were carried out to calibrate the accuracy of the magnetic-based corrosion detection apparatus. A parameter of sensitivity coefficient, k , was proposed to evaluate the corrosion detection sensitivity of the apparatus. An equivalent numerical model was established based on multi-physical simulation to quantify the corrosion degrees and explore the impacts of the frame internal structural parameters. Results show that k is stable and changes linearly with the diameter of steel rods tested. Increasing frame width and foot length can increase k , and adding extra calibration magnetic circuits leads to reduction in k. Overall, the modified magnetic-based apparatus provides a simple, reliable, accurate and non-destructive method for steel corrosion detection. [ABSTRACT FROM AUTHOR]