Study of the behavior of concrete samples with pre-rusted reinforcement in 3% NaCl solution. Corrosion monitoring using polarization curves

• V.E. Kasatkin, I.V. Kasatkina, I.G. Korosteleva, L.P. Kornienko and V.N. Dorofeeva

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31-4, Leninsky prospect, 119071 Moscow, Russia

Abstract: Migrating corrosion inhibitors (MCI) are used to protect steel reinforcement in concrete exposed to aggressive electrolytes containing chloride ions. Previously, we studied the protective effect of the inhibitor IFKhAN-78 on reinforced concrete samples completely immersed in 3% NaCl. It was found that when the concrete was treated with this inhibitor, the protective effect did not exceed 2–3 weeks. After that, the corrosion of the reinforcement significantly increased. The reason for this behavior may be related to the inclusion of a surfactant component in MCI, which facilitates the diffusion of aggressive chloride ions through the concrete layer to the metal from the solution during prolonged immersion. In this study, we examined concrete samples with pre-corroded rebar (to reduce the exposure time) and compared the effects of MCI impregnation, a combination of MCI and phosphate, and a separate surfactant from the inhibitor. Monitoring the condition of the reinforcement by measuring the corrosion potential and corrosion current during a 120-day exposure to the chloride electrolyte confirmed the previously obtained results on the short-term protective effect of MCI. The results of the experiment showed that the presence of surfactants in the impregnation significantly increased the corrosion of the reinforcement during prolonged immersion in the electrolyte. Double impregnation with MCI and phosphate slowed down the corrosion of the steel, but the results were not better than those of the untreated concrete sample.

Keywords: concrete, steel reinforcement, corrosion, migrating corrosion inhibitor, chloride electrolyte, polarization curves

Int. J. Corros. Scale Inhib., 2025, 14, no. 4, 2099-2110
doi: 10.17675/2305-6894-2025-14-4-19

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