In chloride-laden environments, reinforced concrete structures are highly susceptible to steel corrosion, which leads to concrete cracking, spalling, and ultimately, reduced structural safety. Corrosion-induced cracks in concrete provide crucial insights into the corrosion status of rebar and the load-bearing capacity of deteriorated structures. Understanding the mechanisms behind corrosion-induced cracking is therefore of paramount importance. This study investigates the effects of two commonly employed laboratory corrosion methods—galvanostatic (GS) and artificial climate environment (ACE)—on the relationship between corrosion products and corrosion-induced cracks.
A novel approach combining X-ray apparatus with digital image processing techniques is proposed to precisely quantify corrosion products and analyze their continuous development. Through long-term corrosion tests using both GS and ACE methods, the mechanisms behind corrosion-induced crack formation were examined in detail. The study analyzed the growth of corrosion products in both cross-sectional and longitudinal directions, along with the relationships among steel weight loss, corrosion product thickness, and corrosion crack width. The experimental results revealed that the GS method resulted in smaller corrosion-induced cracks, attributed to a smaller steel-to-rust volume expansion ratio, which occurs due to continuous leakage and a lower oxidation degree of corrosion products in GS specimens as corrosion progresses. Additionally, the study highlighted that expansion stress from corner-located rebars restrained the growth of corrosion products on center-located rebars, subsequently limiting crack propagation. Finally, the thickness of corrosion products was used as an input for a three-dimensional finite element model to estimate the distribution of corrosion-induced crack widths, which was further validated against experimental results.