Probabilistic damage analysis of rebar corrosion in recycled aggregate concrete using sideband intensity-based nonlinear ultrasonic technique

The inherent inferiority of recycled aggregate concrete (RAC) necessitates a keen focus on the heightened susceptibility of its steel reinforcement to corrosion. Therefore, accurately predicting the long-term corrosion of steel reinforcement in RAC structures is of significant importance. A series of samples of recycled concrete with embedded steel reinforcement were cast and subjected to accelerated electrochemical corrosion tests. Meanwhile, the extent of corrosion in the reinforcement subjected to varying durations of testing was monitored using a nonlinear ultrasonic technique, with the sideband intensity index (SII) employed to quantify the degree of corrosion damage. Nonlinear statistical regression analysis was performed to establish the correlation between SII and the duration of corrosion. A probabilistic damage analysis was conducted based on the three-parameter Weibull distribution model, followed by the generation of lifetime distribution plots based on the concept of reliability/lifespan. Subsequently, the relationship between corrosion time and damage parameters under different reliability probabilities was determined. The newly developed probabilistic corrosion damage model can estimate the service life for a given duration of corrosion at a specified reliability index. The probabilistic corrosion damage model can serve as a reference for maintenance, design, and lifespan prediction of RAC structures in corrosive environments.