ABSTRACT
Corrosion-induced concrete cracking is a significant durability problem for reinforced concrete structures. Conventional method of examining corrosion progression is upon crushing the corroded samples which led to inaccurate or in some cases misleading estimation. This has hindered the development of rational corrosion models as reliable experimental data are rather limited. In this research, the chloride-induced corrosion progression of the steel bar in concrete was investigated by X-ray Computed Tomography (i.e., XCT). 3D XCT images were obtained and processed to characterize the different material phases. It has been found that pitting corrosion is prone to appear around the voids close to the steel bar, mainly due to the pre-existing supply of oxygen and moisture. In addition, a distinct transverse crack has been identified which is caused by non-uniform corrosion along the reinforcing steel bar. A non-uniform corrosion model was then parameterized based on the XCT results. It can be concluded that the combination of the use of wetting and drying cyclic corrosive environment and the XCT scanning can provide a new method to the non-destructive investigation of corrosion process, rust distribution and corrosion-induced concrete cracking in the reinforced concrete structures.
