Research on time-varying degradation of RC buildings coupled environmental effects and corrosion-induced damage from multi-scale

Abstract

Corrosion of steel reinforcement in reinforced concrete (RC) buildings is influenced by several factors, including oxygen content, chloride ion diffusion, concrete damage, and humidity. A numerical method is presented to evaluate the long-term structural performance of RC buildings under environmental conditions, which takes into account the impact of steel corrosion-induced damage from multi-scale. The macro-index used for calculation is the level of reinforcement corrosion-induced damage, which considers the inter-connected effects of oxygen content, chloride ion, moisture transport, mechanical stresses, and corrosion uncertainties. In the case of RC beams, corrosion tends to occur more severely on the outer edge near concrete surface. When the corrosion factor is taken as 1.0, the calculated compression side corrosion rate of RC beam agrees well with experimental results. Due to the influence of multiple factors, the corrosion of tension-side reinforcement exhibits some degree of variability. Furthermore, the corrosion of tension-side longitudinal reinforcement in RC beams gradually intensifies from beam ends towards mid-span, with corrosion at mid-span being particularly significant. The relationship between corrosion rate and corrosion time obtained from tests falls within the range of calculation results, and the calculated results from micro-scale align favorably with tests conducted to measure crack width.