APPLICABILITY OF X-RAY CT FOR MEASURING CRACKING CHARACTERISTICS AND SHEAR DEFORMATION NEAR CORRODED STEEL BARS IN MORTAR

Abstract

It has been pointed out that corrosion cracking conditions influence the shear capacity of RC structures. To elucidate this, it is necessary to systematically study the relationship between the visualization of corrosion cracks and the stress transfer situation during loading. This study demonstrates the effectiveness of an X-ray computed tomography (CT) system that can take images under loading conditions for visualizing cracks and shear deformation near corroded steel bars in mortar. In the experiments, X-ray CT images were acquired during electrolytic corrosion tests and loading tests of specimens with shear surfaces along the round steel to investigate the section reduction rate and crack propagation in the round steel, and the change in the stress transfer mechanism at the shear surface with or without corrosion during loading. The results showed that the relationship between the arrangement of the round steel bars and the degree of corrosion, and the three-dimensional distribution of corroded crack widths could be calculated from the X-ray CT images. The changes in the stress transfer mechanism due to corrosion cracks were also clarified from the load-displacement relationship inside the specimen with or without corrosion of the steel bars.