Multiscale modeling of steel corrosion in concrete based on micropore connectivity. (15th April 2022)

• Record Type: Journal Article
• Authors: Ohno, Motohiro; Limtong, Pakpoom; Ishida, Tetsuya
• Is Part Of: Journal of building engineering. Volume 47(2022)
• Publication Date: 2022-04-15
• Subjects: Corrosion -- Micropore -- Pore connectivity -- Multiscale modeling -- Numerical simulation; Building -- Periodicals; 690.05
• DOI: 10.1016/j.jobe.2021.103855
• Languages: English
• ISSNs: 2352-7102

Abstract

Abstract: This paper presents coupled multiscale models of steel corrosion in concrete, focusing on micropore connectivity. The ohmic control is represented by the effective surface area of steel in contact with interconnected pore solution. The oxygen diffusion control is simulated based on oxygen transport through the Nernst's diffusion layer assumed in the connected pore solution. The model validation with experimental data of multiple previous studies indicates that both the exponential change of corrosion current under the ohmic control and the oxygen diffusion control for higher relative humidity (RH) levels can be reasonably simulated. Also, a parametric study on water-to-cement ratios implies that moisture in nm-scale micropores is not involved in corrosion reactions. Moreover, 10-year-long simulations indicate that the long-term weight loss of steel is significantly affected by external RH. Therefore, for accurately predicting the long-term corrosion in real reinforced concrete structures, collecting actual RH data in the surrounding environment is important. Highlights: New models of steel corrosion in concrete focused on pore connectivity are proposed. Ohmic control is represented by the amount of interconnected pore solution. Oxygen diffusion control is simulated based on the Nernst's diffusion layer. The models reasonably simulate corrosion rates for various relative humidity levels.