Three dimensional imaging of reinforcement corrosion using micro-computed tomography: Literature review

Abstract

A deeper understanding of steel reinforcement corrosion and corrosion-induced cracking in concrete structures is crucial for taking preventive measures and performing effective and efficient repair. Recently, researchers started utilizing high-resolution and non-destructive micro-computed tomography (µCT) imaging systems to investigate the diffusion of corrosion products and the resulted cracks within structural elements throughout the corrosion process. Natural and accelerated reinforcement corrosion modes are induced using two techniques, namely: impressed current and wet-dry cyclic methods. The test specimens are scanned periodically using µCT during the corrosion process to accurately capture microstructural change. The reported findings demonstrated the potential of using µCT imaging to monitor the corrosion diffusion and crack propagation in addition to measuring the mass loss of reinforcement. This research area, however, is still relatively new with many uncovered areas that need to be investigated. Therefore, the main objective of this article is to provide a comprehensive review of the current research progress by reviewing the specifications of examined specimens, the applied corrosion-induction conditions, and the utilized imaging parameters to capture high-resolution µCT images. The reported corrosion diffusion and crack propagation mechanisms are presented. The effects of impressed current, type of steel reinforcement, structural defects, and physical confinement on the corrosion and cracking processes are discussed. Also, the accuracy of µCT measurements of reinforcement mass loss is described.