Numerical simulation of the service life of reinforced concrete structures subject to pitting corrosion

Resumo

Chloride corrosion is the most severe deterioration mechanism that affects reinforced concrete struc-
tures, especially in regions with a marine atmosphere. Electrochemical reactions begin when the critical chloride

ion content is reached on the surface of the bar, promoting the depassivation of the steel. In this work, a two-
dimensional numerical model based on the Finite Element Method (FEM) is proposed to analyze the service life

of reinforced concrete beams subjected to pitting corrosion. Two-dimensional triangular elements with Mazar’s
damage criterion were used for the concrete matrix and truss elements with elastoplastic behavior were used for
the reinforcements, coupled through the embedded technique. The period of initiation of the corrosive process is
determined considering exclusively the mechanism of diffusion of chloride ions, using Fick’s laws. Deterministic
models based Faraday’s laws available in the literature are used for the analysis of the propagation phase, simulated
by reducing the cross section area of the reinforcement over time. Service life is estimated by the crack opening

limit state, according to the Brazilian standardization ABNT NBR 6118:2014. Numerical applications are presen-
ted to demonstrate the robustness of the implementations carried out, revealing the importance of the thickness of

the concrete cover and the water / cement ratio in the service life of the structural element.