Probabilistic analysis of the corrosion initiation in concrete structures subjected to chloride ingress using the Boundary Element Method

Resumo

Reinforcement’s corrosion is the main cause of durability reduction in reinforced concrete structures.
Besides, the chloride ingress is the main agent in this problem. The reinforcement’s corrosion process occurs in
two stages: in the first, known as the initiation period, chloride ions penetrate into concrete pores and accumulate
at the concrete/reinforcement interface, which lead to the depassivation when the threshold concentration is
reached. After the depassivation, the propagation period starts, which triggers the reinforcement’s corrosion and
the structural collapse. Because of the faster structural safety reduction observed in the latter stage, the initiation
period is often adopted as structural service life. In this regard, this study applies the two-dimensional transient

formulation of the Boundary Element Method (BEM) for the chloride diffusion modelling. Because of the non-
requirement of the domain mesh, the chloride concentrations at the domain are accurately assessed. Moreover, this

problem is properly analysed solely in the probabilistic context because of the huge randomness over the governing
variables. The Monte Carlo Simulation assesses the probabilities of failure herein, which accounts for the failure
scenarios described by the BEM. In addition to the phenomenological random variables, cracks positioned at the
cover account for the inherent concrete cracking and describe preferential ingress paths.