Modeling of corrosion-induced concrete cover cracking: A critical analysis

This article critically reviews a number of empirical, analytical and numerical models to predict the time to cracking due to corrosion of reinforcing bars in reinforced concrete structures. The empirical models are generally based on simple mathematical expressions and primarily depend on corrosion rate, cover depth and diameter of reinforcing bars. The analytical and numerical models, on the other hand, involve more refined, mechanistic considerations and include strength and stiffness parameters of concrete and type of corrosion products. It was observed that the majority of the investigated models were only capable of adequately predicting the time-to-cracking for the experiments to which they were fitted. The (generally) highly complex analytical and numerical models did not necessarily lead to more accurate predictions than those obtained via simple, empirical models. This is believed to be due to the fact that current models do not consider all occurring processes and that fitting parameters such as the “porous zone” cannot compensate for this. A number of areas for further research were identified, including development of prediction models, taking into consideration factors such as corrosion chemistry and time-related effects, corrosion morphology, and a more realistic representation of the corrosion accommodating region.

► There is no correlation between the degree of complexity of time-to-corrosion models and the accuracy of the predictions.
► Existing models do not consider all occurring processes. Fitting parameters such as “porous zone” can’t counterbalance this.
► In development of models, the chemistry of corrosion products and existing time dependencies should be included.