Quantitative image analysis on the filling proportion of corrosion products in reinforced concrete using X-ray computed tomography

Corrosion-product filling inhibits corrosion-induced cracking in reinforced concrete (RC) structures, thereby affecting structural deterioration. However, the accurate quantification of corrosion-product filling has challenged the scientific and engineering communities. In this study, a novel method for quantifying the filling proportion of corrosion products /3F at the macro- and meso-scales using X-ray computed tomography and image segmentation algorithms was proposed. This method was applied to RC specimens exposed to chloride-rich environments and compared with conventional methods. The results showed that conventional quantitative methods underestimated /3F owing to a lack of understanding of the corrosion products filling into air voids and the aggregate-mortar interface, and those overflowing from the specimen. A positive correlation between /3F and corrosion propagation as well as moisture content in the environment was observed, whereas /3F was negatively associated with concrete cover thickness.