On the effect of surfactants in the composition of the corrosion inhibitor IFKhAN-78 during prolonged complete immersion of concrete in 3% NaCl solution

• 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: Previous studies of concrete samples treated with the migrating inhibitor IFKhAN-78 have shown that when completely immersed in an aggressive chloride electrolyte, this inhibitor does not provide long-term corrosion protection. A sharp increase in the corrosion rate of steel occurs within 3–4 weeks after immersion in 3% NaCl solution. At the same time, concrete without the inhibitor maintains low corrosion rates for reinforcement for at least 3–4 months. On the other hand, this inhibitor in the model pore solution with 3% NaCl provides excellent protection for steel. To explain this paradoxical result, we have proposed the hypothesis. Since IFKhAN-78 contains a surface-active additive along with the inhibiting components to facilitate the composition’s penetration through the concrete layer, this additive can also facilitate the leaching of the inhibitor from the pores during prolonged immersion in the solution. Additionally, the surface-active additive can promote the penetration of aggressive chlorides from the external solution into the reinforcement. Both effects, the decrease in inhibitor concentration and the increase in chloride concentration near the reinforcement surface, can contribute to the development of corrosion on the metal. In this work, we compared the corrosion and electrochemical behavior of two batches of concrete treated with the inhibitors IFKhAN-78 (containing surfactants) and its analogue IFKhAN-78* without any surfactants. During the 4-month experiment, we regularly measured the amount of the active component of the inhibitors that was leached into the external electrolyte. At the end of the exposure, we compared the chloride content in the pores of the concrete from these two concrete batches. The obtained results fully confirmed the previously proposed hypothesis about the mechanism of the negative effect of surfactants during prolonged complete immersion of concrete in an aggressive electrolyte.

Keywords: reinforced concrete, inhibitor IFKhAN-78, surfactant, corrosion, monitoring

Int. J. Corros. Scale Inhib., 2026, 15, no. 2, 189-209
doi: 10.17675/2305-6894-2026-15-2-12

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