Visualized investigation of defect in cementitious materials with electrical resistance tomography.

Highlights • Electrical resistance tomography (ERT) method is proposed to visually detect the defect in cementitious materials. • A similarity calculation based on color histogram is introduced to evaluate the image from ERT measurement. • The factors effecting on the image quality of ERT is analyzed and discussed. Abstract Electrical resistance tomography (ERT) method is proposed to visually investigated of the defect in cementitious materials. Specimens with one precast defect are made with different water-cement (w/c) ratio and detected using the embedded electrodes. The experimental images are assessed with a similarity evaluation method based on color histogram. In addition, the electrical resistivity and moisture content of the specimens are measured simultaneously to explore its effects on the quality of the imaging results. The results show that the moisture content is the main factor influencing the resistivity of the specimens in the early hydration reaction while the w/c ratio becomes the main factor effecting the resistivity after the early hydration reaction. For the multi-defect detecting, the influence of electrical soft field effect cannot be neglected. The experiment results imply that ERT technique has potential in defect detection and in-situ monitoring in cement mortar. [ABSTRACT FROM AUTHOR]