Probabilistic corrosion time initiation modelling in reinforced concrete structures using the BEM

Abstract

The reinforcement’s depassivation in reinforced concrete structures occurs when the chloride concentration at the reinforcement’s interface reaches the threshold content. The depassivation phenomenon starts the propagation period, in which huge mechanical degradation processes are triggered. Moreover, it is well established that the propagation period is considerably shorter than the initiation period. Therefore, the accurate prediction of the corrosion time initiation is a major issue in structural durability domain. This study presents a transient formulation based on the Boundary Element Method (BEM) for the corrosion time initiation assessment. The diffusion fields evaluated by the BEM are utilized into a probabilistic framework, which enables the assessment of probabilistic values for corrosion time initiation. Therefore, the formulation handles properly the uncertainties in this problem, which is largely subjected to randomness. Three applications are presented. The robustness and accuracy of the proposed approach over classical analytical models are highlighted.

Transient Modeling of Corrosion Protection Systems With BEM-Electrical Circuit Hybrid Model

“…𝐀, 𝐄 ∈ ℝ (2N+1)×(2N+1) , 𝐁 ∈ ℝ (2N+1)×N , 𝑥 ∈ ℝ 2N+1 , 𝑢 ∈ ℝ N . Let us notice that in (7), 𝑈 𝑃𝑂𝐿 and 𝐼 𝑃𝑂𝐿 are nonlinearly coupled by (5).…”

“…To solve (7), the backward Euler method is used. The nonlinear problem is solved using the Newton-Raphson method with the vector quantity 𝑅𝑒𝑠 defined at each time step by:…”

“…In [6], a transient modelling of ICCP systems has been proposed, but the approach is not transient, but rather multi-static. Recently, a transient BEM approach has been presented [7] but the application field and the associated assumptions are too far from the ICCP modelling.…”

Probabilistic chloride diffusion modelling in cracked concrete structures by transient BEM formulation

“…Yang et al [26], [27] adopted it for the diffusion modelling of chloride ions into cover thickness of concrete structures, and Chen et al [28] analysed chloride diffusion in high-performance concretes, in which the BEM performance was compared against experimental results. Pellizzer and Leonel [29] modelled chloride ingress in concrete pores using the time-dependent BEM approach for diffusion, and later [30] proposed a Reliability-Based Design Optimisation (RBDO) formulation for the probabilistic optimisation of cover thickness in concrete structures subjected to chloride penetration. The present study contributes to the field applying the transient BEM approach for the time-dependent diffusion modelling of chlorides in concrete structures.…”

“…Nevertheless, the computational effectiveness of BEM enables a probabilistic description via MCS. Very few studies have adopted this coupling scheme [29], [30], [34], thus motivating this research, which deals with the probabilistic modelling of chloride ingress in concrete pores.…”