Modelling steel corrosion under concrete non-uniformity and structural defects

Reinforcement corrosion is one of the most frequent durability problems among ageing concrete structures. Macrocell corrosion is greatly affected by both concrete properties and the steel-concrete interfacial conditions. Inaccurate interpretations of these characteristics lead to unrealistic estimations of early corrosion propagation. Carbonation-induced macrocell corrosion, including the impact of structural defects formed by concrete casting, is addressed in this study. The non-uniform corrosion cell created due to the progressive carbonation of concrete is numerically obtained by combining chemophysical modelling and multiscale homogenisation. The macrocell corrosion under material non-uniformity is then studied by electrochemical modelling based on finite element method. The developed method is first validated against reported experiments to further initiate an in-depth discussion on the significance of material non-uniformity on corrosion modelling either with or without structural defects. The present study is particularly important for advancing the service life monitoring and assessment of ageing concrete structures. •The frequent durability concern of macrocell corrosion is numerically investigated.•The influences of concrete non-uniformity and structural defects are assessed•A method coupling chemophysical and electrochemical FE modelling is developed•A novel semi-empirical multiscale homogenisation scheme is established•The proposed methodology is validated against a series of experimental studies