Fundamental Study on Imaging Method of Steel Corrosion in Concrete using Inverse Analysis of Electromagnetic Field Response

A highly visible non-destructive evaluation method to monitor the progress of steel corrosion in concrete is strongly required. The purpose of this study is to propose an evaluation method using the electromagnetic field response, aiming to visualize the corrosion in a perspective view. At first, the detection mechanism of electromagnetic field response of fundamental notched patterns on the steel surface was considered. Second, an inverse problem analysis was performed. In detail, a visualizing method in the reverse direction that transforms the electromagnetic field response into a combination of magnetic changes of elementary waveforms of square-wave shaped surface and a reproducing method of the corrosion shape on 2-Dimensions by combining the elementary waveforms were proposed. The position and width of the defects, as well as the ratio of the depth of each defect, were well visualized.