Reliability-based prediction of chloride ingress and reinforcement corrosion of aging concrete bridge decks

This paper presents a probabilistic approach for predicting the chloride contamination of concrete and reinforcing steel corrosion, which takes into account the uncertainty associated with the analytical models of chloride transport, corrosion initiation, as well as damage accumulation, material properties, structural dimensions, and applied environmental and mechanical loads. The proposed approach is illustrated on an aging reinforced concrete bridge deck that has been exposed to chlorides from deicing salts for forty years. An extensive non-destructive and destructive evaluation of the corrosion-damaged deck was undertaken. The field survey data showed a considerable level of variability in all parameters measured with coefficients of variation ranging from 34% for the concrete cover depth to 86% for the diffusion coefficient. The distributions of the chloride concentration at the level of the top reinforcement mat and the time for its corrosion initiation were generated using Monte Carlo Simulation. The simulated results were very close to the field data, which illustrates the prediction capabilities of probabilistic methods as opposed to deterministic methods.