Coupling limit states of corrosion initiation and corrosion induced crack opening - sensitivity analysis of model parameters

A normal approach to the Service Life Design of reinforced concrete will typically consider the limit state of corrosion initiation as the defining durability limit state. Rarely are other limit state considered such as corrosion propagation or corrosion induced cracking and spalling due to the greater uncertainties in the models that describe the deterioration mechanisms. Most models capture the process of the initial phase of degradation. These models disregard the actual damage, i.e. the corrosion of the reinforcing steel. As a result, the Service Life Design established to date only considers the end of the initiation phase of the degradation process, or, in other words, the onset of damage (time of depassivation or onset of corrosion) as a critical limit state. Corrosion and its consequences are not considered, which may lead to a substantially shorter estimated service life of the structures. Comprehensive investigations were recently undertaken on the depassivation of steel reinforcement and on crack formation in concrete which have resulted in an analytical prediction model for corrosion-induced cracking occurring in the surface zones of structural components. This paper presents a sensitivity study of the main model parameters for the corrosion induced cracking when coupled to the chloride induced corrosion initiation model.