This study reports on a fundamental study on the investigation of electrical resistivity measurements for detecting internal defects or damages, which aims at developing Electrical Resistance Tomography techniques based on electrical resistivity distribution measured via Wenner method. In particular, this study examined the changes of resistivity upon the presence of damages in the bottom of concrete specimens which mirror internal cracking not visually observed on the concrete surface in typical reinforced concrete structure. For the experimental investigation, ten electrodes comprising stainless steel and electric conductive epoxy were partially embedded on the surface of prism concrete specimen. Then, electrical resistivity was measured via Wenner method using four electrodes selected among the electrodes placed 20 mm apart each other. In addition, analytical investigation simulating the influence of internal damages on current flow and measured voltage or potential was carried out by FEM analysis. As a result, electrical resistivity increased depending on the depth of slits with 1 mm width, which was sawed at the bottom of the specimen. This could be attributed to the influence of the damages on the current flow and equipotential planes, thus suggesting that there is a good possibility that internal damages can be detected based on the changes and the distributions of the electrical resistivity.
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