Corrosion damages of reinforced concrete characterized by X-ray CT and DVC techniques

Abstract

X-ray microcomputed tomography (X-ray CT) technique was performed to monitor the whole corrosion cracking process of a cylinder reinforced concrete specimen non-destructively. Based on gray threshold separation and 3D reconstruction technology, the spatial distributions of each substance were obtained. Combined with Digital Volume Correlation (DVC) technique, the development of corrosion depth, generation and migration of corrosion products, variation of internal strain field and crack propagation during the corrosion process were all analyzed. The experiment results indicate that the electric current accelerated method can lead to a non-uniformity corrosion at the early age. The distribution fields of rusts and strain are affected by the micro- and meso- structure of concrete. A turning point of maximum principle strain along the cracking path can be identified as the critical point at which micro-cracks of concrete connect and propagate into macro-cracks. The statistical analysis reveals that the gray values of mortar matrix, corrosion products, steel bar and coarse aggregates in corroded concrete follow a Garrison distribution, while the pores do not.