Stochastic Modeling of Reinforced Concrete Cracking due to Nonuniform Corrosion: FEM-Based Cross-Scale Analysis

Chloride-induced rebar corrosion is one primary cause of early cracking of reinforced concrete (RC). A model to accurately predict the time before steel corrosion and concrete cracking, with due consideration of the heterogeneous nature of concrete matrix, is highly desired by maintenance engineers. This paper presents the results of a research study directed at developing a stochastic numerical method to model the microstructure of concrete matrix and to predict the service life of RC in three key steps: chemical ingress, steel corrosion, and concrete cracking. The finite-element method (FEM) is employed to model the ingress of multiple chemical species into variably saturated concrete matrix. By using Faraday's law, rebar corrosion is modeled in a mixed localized-uniform pattern and quantified as a transient displacement boundary condition for subsequent analysis of concrete cracking. The proposed FEM model is validated by using laboratory experiments and applied to predicting the corrosion-induced cracking of an RC bridge deck.