TRANSIENT BOUNDARY ELEMENT FORMULATION APPLIED FOR CORROSION TIME INITIATION ASSESSMENT IN REINFORCED CONCRETE STRUCTURES SUBJECTED TO CHLORIDE INGRESS

Resumo

The reinforcements’ depassivation in reinforced concrete structures caused by chloride
ingress occurs when the chloride concentration at the reinforcements’ interface reaches the threshold
content. The main transport mechanism of chlorides ions into concrete pores is the diffusion. Then, the
realistic chloride diffusion modelling into concrete pores enables the accurate determination of the
corrosion time initiation. This study presents a transient formulation based on the Boundary Element
Method (BEM) applied for diffusion problems, which provides the accurate assessment of the
corrosion time initiation. The diffusion fields evaluated by the BEM are utilized into a probabilistic
framework, which determines probabilistic values for corrosion time initiation. Therefore, the
uncertainties are properly quantified in this model by an approach based on simulation. Two
applications are presented, which illustrate the accuracy and robustness of the proposed formulation
when compared with classical analytical approaches.