Space-Averaged Non-Local Analysis of Electric Potential for Polarization Reactions of Reinforcing Bars in Electrolytes

Abstract

For assembly of reinforcing bars embedded in electrolyte like concrete, space-averaged non-local analysis for electric potential is proposed and the anodic and cathodic polarization reactions are formulated in association with the exchange of electric charge between steel reinforcing bars and the electrolyte as matrix. In order to verify the proposed scheme like smeared crack modeling of cracked concrete mechanics, transparent sodium poly-acrylate superabsorbent polymer with calcium hydrate solution was made so that we may identify the location of anodic and cathodic reactions of reinforcement at regular time intervals. The analytically predicted locations of corrosion were compared with the experiments, and its functionality of non-local formulation was verified and its applicability was experimentally examined.

Space Averaging of Electric Field accompanying Corrosion of Reinforcement and its Verification by Pseudo-Concrete

“…The numerical simulation is conducted with the thermomechanistic platform, which handles multi-chemo-physics of fluid, thermal, chemical and electro-magnetic events (Maekawa et al 2015(Maekawa et al , 2019Gong et al 2020;Iwama et al 2020). The cement hydration module is linked with the multi-physical analysis through the formation of pore structures by various hydrates, which makes the platform an integrated tool for durability evaluation of structural concrete (Maekawa et al 2003).…”

“…If dealing with the discrete domain, the ion flux in electrolyte (Jion-b) and electron flux in electrolyte (i e-b ) and steel (i s-b ) at the boundary of polarization follow Eqs. ( 4) and ( 5) (Maekawa et al 2019;Wang et al 2021), where the term i corr stands for the corrosion current density induced by electro-chemical reaction.…”

“…Meeting the engineering challenge requires grasp of the degradation mechanism of the whole analytical domain instead of focusing only on a specific spot. Then, a global picture of the whole macro-cell circuit including both anodic and cathodic reactions is being aimed for structural concrete (Maekawa et al 2019;Wang et al 2021). A number of theoretical (Bažant 1979a(Bažant , 1979b and numerical (Hsu et al 2000;Maruya et al 2007;Liu et al 2012;Hong et al 2017;Xia et al 2019) studies have analyzed macro-cell corrosion, anti-corrosion and electrochemical reparation (Liu et al 2022;Meng et al 2022) by considering the chemical components (alkalinity, O2, CO 2 , ions equilibrated with solid minerals) of the electrolytes of concrete matrix.…”

“…The authors have tried an integrated simulation platform to overcome the above-mentioned shortcomings (Maekawa et al 2019;Wang et al 2021). The dynamic coupling of electrical and chemical fields is solved by time sequence with adopting an overlaid finite element scheme to allow simulation targets in practice.…”

“…A geochemical solution platform is also integrated to solve the multi-ion equilibrium (Appelo and Postma 2004;Elakneswaran and Ishida 2014). To further investigate the framework of corrosion including anticorrosion, numerical simulation and experimental verification are presented with pseudo-concrete materials that are transparent in nature and have an ionic chemical composition similar to the pore solution of concrete composites to serve as the electrolyte (Maekawa et al 2019). With a pseudo-concrete matrix containing reinforcement, information for verification of the modeling can be obtained, such as the location of reduction and oxidation poles by visual inspection and time-dependent ionic concentration, by picking up a small sample with less destruction to the specimen.…”