Deterioration of passivation film caused by carbonation in reinforced concrete: An electrochemical and nanoscale perspectives

WZ Sun and CB Liu and F Hong and P Wang and Y Zhang and XP Wang and DS Hou and MH Wang, JOURNAL OF BUILDING ENGINEERING, 106, 112524 (2025).

DOI: 10.1016/j.jobe.2025.112524

The durability of reinforced concrete can be significantly threatened by carbonation, which can damage the passive film on steel, contributing to corrosion. This study investigates the effects of carbon dioxide (CO2) molecules on the stability of passivation films were investigated by using electrochemistry and reactive molecular dynamics (MD) simulations. Various defects on the passivation film surface were incorporated to simulate real-world conditions. Polarization curves and impedance spectroscopy show a marked deterioration in the electrochemical behavior of the passivation film after carbonation, shedding light on the complex relationship between carbonation and passivation phenomena. Additionally, reactive MD simulations provide an atomic-level insight into the interaction between CO2 and passivation film defects. Our findings reveal that CO2's erosive impact is localized to specific defect types, with simulations identifying the binding configurations that increase the susceptibility of certain regions within the passivation film. This study highlights how CO2 attacks the surface of the passivation film and presents a nanoscale view of the process, contributing to a deeper understanding of carbonation-induced corrosion mechanisms.

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