Probabilistic model for time to cover cracking due to corrosion

The time to cover cracking is widely used as a service life indicator in the assessment of deterioration of corrosion-affected reinforced concrete structures. This paper presents a general probabilistic procedure for prediction of time to cover cracking. Within this procedure, the response surface method (RSM) is employed to calibrate a new model for calculating of radial displacement required for cover cracking based on the results obtained from the finite element (FE) analysis. By taking advantage of the central limit theorem (CLT), simple but accurate probabilistic models for prediction of time to cover cracking that only rely on the knowledge of first and second moments of basic random variables are derived. Rigorous simulation analysis has proved the accuracy of these models. It is shown in the paper that using this probabilistic procedure, factors affecting randomness of time to cover cracking can be easily identified. It is also shown that the time to cover cracking is highly variable with the concrete cover, tensile strength of concrete, corrosion current density, and the model error as the most influential factors on its randomness.