Identification of corrosion products and 3D distribution in reinforced concrete using X-ray micro computed tomography

• Published in: Construction & building materials 2019-05, Vol.207, p.304-315
• Main Authors: Fang, Guohao, Ding, Weijian, Liu, Yuqing, Zhang, Jianchao, Xing, Feng, Dong, Biqin
• Format: Article
• Language: English
• Subjects: 3D distribution; Backup software; CAT scans; Corrosion (Chemistry); Corrosion products; Hydroxides; Iron oxides; Non-destructive test; Oxides; Reinforcement corrosion; Steel corrosion; Tomography; X-ray micro computed tomography
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.02.133

•Different types of corrosion products are non-destructively identified by X-ray µCT.•The evolution of corrosion products can be determined as a function of time and space.•Corrosion mechanism is further discussed according to corrosion evolution characteristic. The main purpose of this study is to non-destructively monitor the formation and development of corrosion products in reinforced mortar with the help of X-ray micro computed tomography (X-ray µCT). A new method based on the relationship between the linear attenuation coefficient and CT number as well as greyscale value is built to identify different type of corrosion products. Based on this method, two categories of corrosion products including iron oxides and iron hydroxides are identified in this research. Additionally, the corrosion mechanism and the interaction between different types of corrosion products are discussed according to the characteristics of corrosion evolution. Furthermore, the volumetric expansion ratio of corrosion products is quantified (from 2.71 to 3.97). This method provides a new angle to investigate the formation and development of reaction products, which contributes to further understand the corrosion process in reinforced concrete.