A framework for evaluating steel loss from the evolution of corrosion-induced deflections in reinforced concrete beams with non-uniform reinforcement corrosion

Artikel i vetenskaplig tidskrift, 2024

Describing corrosion propagation throughout the corrosion process, prior to the extraction and assessment of reinforcement bars, is challenging. In this paper, a framework is proposed for describing corrosion propagation from corrosion-induced variations in deflection for reinforced concrete beams, based on the experimental results of beams simultaneously subjected to either an imposed relative displacement or cyclic loading along with accelerated corrosion through impressed current. Strain measurements from distributed optical fiber sensors were used to calculate the deflection and crack distribution over time. Given the characterization of the initial current density, the framework allowed for the calculation of corrosion development based only on the measured corrosion-induced deflections. The framework was verified, as revealed by the strong agreement between the pit volume loss obtained from 3D scanning of the reinforcement bars and the losses calculated using Faraday's law. Moreover, a second mechanism contributing to corrosion-induced variations in deflection, in addition to the reduced stiffness due to pitting corrosion, was observed for the case with cyclic loading and attributed to bond degradation. Furthermore, for load cycles with similar load level, it was shown that the increase in deflection occurred only when there were intermediate load cycles with a higher load level, suggesting that the assumed bond degradation occurs only when the load surpasses a previous threshold.