Numerical Simulation of Non-Uniformly Distributed Corrosion in Reinforced Concrete Cross-Section

Abstract

Reinforced concrete structures can be strongly damaged by chloride corrosion of reinforcement. Rust accumulated around rebars involves a volumetric expansion, causing cracking of the surrounding concrete. To simulate the corrosion progress, the initiation phase of the corrosion process is first examined, taking into account the phenomena of oxygen and chloride transport as well as the corrosion current flow. This makes it possible to estimate the mass of produced rust, whereby a corrosion level is defined. A combination of three numerical methods is used to solve the coupled problem. The example object of the research is a beam cross-section with four reinforcement bars. The proposed methodology allows one to predict evolving chloride concentration and time to reinforcement depassivation, depending on the reinforcement position and on the location of a point on the bar surface. Moreover, the dependence of the corrosion initiation time on the chloride diffusion coefficient, chloride threshold, and reinforcement cover thickness is examined.

Cracking in Reinforced Concrete Cross-Sections Due to Non-Uniformly Distributed Corrosion

“…The points of loading application are presented in Figure 16 . The data presented in Table 4 have been calculated according to the model presented in [ 26 ].…”

“…The turning point is the moment when the rates of rust production calculated with both models are equal. The thorough analysis and calculations of the mass of rust have been presented in [ 26 ].…”

“…The location of points with passive layer decomposition is random and depends on the porosity of the concrete, properties of pore solution and mechanical influences [ 26 ]. The description of the electro-chemical process occurring in the propagation phase of corrosion can be found in [ 2 , 3 , 4 , 8 , 10 , 28 , 29 , 30 ].…”

“…The description of the electro-chemical process occurring in the propagation phase of corrosion can be found in [ 2 , 3 , 4 , 8 , 10 , 28 , 29 , 30 ]. It must be pointed out that, due to varying concrete cover carbonation and content of chloride ions around the bar, the geometry of rust is rather irregular, i.e., rust is hardly ever uniformly distributed around the reinforcement [ 26 ]. The comparison of those two situations is presented in Figure 1 .…”

Simulation Approach for Random Diffusion of Chloride in Concrete under Sustained Load with Cellular Automata

“…Literature [28] considered the effect of the concentration of chloride ions on reinforcement erosion, and established an analysis method for evaluating the durability and reliability of reinforced concrete structures under chloride ion corrosion by using 2D CA technology. Considering the migration phenomenon and corrosion current of oxygen and chloride ions, German et al [29] analyzed the relationship between corrosion time and chloride ion diffusion coefficient, chloride ion threshold, and thickness of the protective layer of steel reinforcement by combining CA and other numerical methods. Based on mesoscopic features, Ruan [30] proposed a refined cellular automaton approach that improves the efficiency of simulation of chloride ion erosion processes in concrete.…”