Numerical approach about the effect of the corrosion on the mechanical capacity of the reinforced concrete beams considering material nonlinear models

Abstract

Every structure is subjected to the effects of time and environment on which they are located. The consideration of these effects and their consequences in design phase is called nowadays as durability analysis of the structural system. The corrosion of the reinforcement steel through the chloride penetration inside the concrete is the main cause of the lifetime deterioration of the reinforced concrete structures. As a direct consequence, the corrosion affects the resistant capacity of the structural elements as the process evolves over time. Therefore, the appropriate prediction of the structural lifetime depends directly of the prevision capacity of those effects over the behavior of the structural systems. In this work, a mechanical model that combines the corrosion effects over the reinforcement and the concrete and steel material nonlinear responses is proposed to predict the resistant loss of reinforced concrete beams over the time. The steel and concrete nonlinear behavior was modeled by model based on unidimensional plasticity theory and damage mechanics, respectively. The Fick’s laws and empirical methods based on the Faraday’s laws were used to represent chloride penetration inside concrete and reinforced degradation, respectively. A simplified process was adopted to simulate the corrosion beginning in different times over the structure. The results showed that the rate of loss resistant capacity of the analyzed beam is higher in the first years after the beginning of corrosion and tend to stabilized in subsequent years. Furthermore, the structural behavior is very sensitive regarding the considered corrosive effects in the analyses.

Numerical analysis of reinforced concrete beam subject to pitting corrosion

“…Following Vu and Stewart (2000), Val and Stewart (2003), Liberati et al (2014) and Pellizzer, Leonel and Nogueira (2018), in this study Fick's laws are adopted to estimate the depassivation time of the reinforcing steel. Therefore, the initiation stage is evaluated analytically by Fick's laws, considering the phenomenon of chloride diffusion.…”

“…Following Liberati et al (2014), Cao and Cheung (2014) and Pellizzer, Leonel and Nogueira (2018), it is assumed that the diffusion coefficient and the surface concentration of chloride ions remain constant over time. For a review of non-constant diffusion coefficient and superficial chloride concentration, the reader is invited to consult the work of Dominicini and Calmon (2017).…”

“…Among the various phenomena of mass transport, ionic diffusion stands out as the main transport mechanism of chloride ions and, therefore, the initiation stage can be consistently modeled considering it as an isolated mechanism (VU; STEWART, 2000;CHERNIN;STEWART, 2009). Diffusion develops in the presence of a concentration gradient; thus, modeling of diffusion can be adequately approached by Fick's laws (STEWART, 2004;MEDEIROS, 2008;GUZMÁN;GÁLVEZ;SANCHO, 2011;PELLIZZER;LEONEL;NOGUEIRA, 2018).…”

Models for the Prediction of Service Life of Buildings – A Review

“…The second way by which the integrity of reinforced concrete is affected is the delamination between the remaining reinforcement and the concrete member as well as the concrete cover. This is brought about by corrosion product that occupies more volume than the reinforcing steel had initially occupied (Cheung, andKyle, 1996 andPellizzer, Leonel andNogueira, 2018).…”

Time-Dependent Reliability of Reinforced Concrete Considering Chloride Penetration via Boundary Element Method

“…For reinforced concrete structures, in particular, one significant degradation mechanism is corrosion induced by chlorides penetration (Comité Euro-Internacional du Béton, 1992;Gonzalez et al, 1995;Cascudo 1997;Val and Melchers, 1997;Val and Stewart, 2003;Apostolopoulos and Papadakis, 2008;Suo and Stewart, 2009;Zhang et al, 2010). Several studies show that, after depassivation of reinforcement bars due to chloride penetration, structural safety decays sharply (Enright and Frangopol, 1998;Weyers, 1998;Vidal et al, 2007;Dang and François, 2013;Pellizzer et al, 2018).Due to the fast strength reduction, due to corrosion and after depassivation, the largest part of the structures life corresponds to the despassivation time. But this time is also subject to significant uncertainties, due to exposition to random chloride concentrations, variations in concrete cover due to workmanship, and variations in diffusive properties of concrete.…”