Environmental testing of the efficiency of IFKhAN-80, an inhibitor for corrosion protection of steel reinforcement in concrete

Abstract

Environmental tests of the efficiency of IFKhAN-80, a corrosion inhibitor for steel reinforcement in concrete, have been carried out. It has been found that the electrochemical criteria for the estimation of the corrosion behavior of steel reinforcement in concrete recommended by GOST (RF State Standard) 31383-2008 are not informative under the test conditions used. In view of this, the effect of IFKhAN-80 on the kinetics of corrosion spot growth on steel surface has been analyzed. In the absence of an inhibitor, corrosion of reinforcement steel already occurs in the course of hardening of chloride-containing concrete. Once hardening is completed, the growth rate of corrosion spots decreases abruptly. The area of corroded surface remains unchanged for 6 months, then the growth of corrosion spots on the metal surface resumes. Addition of IFKhAN-80 with tempering water in amounts recommended by the developers slows down corrosion in the course of concrete hardening and during exposure under natural conditions. Application of IFKhAN-80 onto the surface of concrete samples in amounts recommended by the developers can arrest the growth of corrosion spots for a long time. Key words: corrosion inhibitors, migrating corrosion inhibitors, corrosion in concrete, reinforced concrete, IFKhAN-80.Received: August 7, 2016. Published: September 22, 2016. doi: 10.17675/2305-6894-2016 Corrosion inhibitors (both contact and migrating ones) are widely used for the protection of reinforced concrete structures [1][2][3][4][5][6][7]. Recently, a new corrosion inhibitor for concrete steel reinforcement was developed at the Institute of physical chemistry and electrochemistry of the Russian Academy of Sciences. It is called IFKhAN-80 and is positioned as a versatile formulation. It is a 30% aqueous solution of a non-volatile compound modified by addition of a surfactant. According to laboratory tests, IFKhAN-80 is efficient both when introduced into concrete with tempering water and when applied to a concrete surface.The purpose of this study was to estimate the efficiency of IFKhAN-80 under natural conditions.

Corrosion and electrochemical behavior of steel in hardening concrete

“…Concrete carbonation is a slow process, and depassivation sites (pits) appear on the reinforcement by the above mechanism for a long time after reinforced concrete structures have been put into service. However, the results published previously [3,4] give a reason to believe that reinforcement can undergo pitting even during concrete curing when the pore liquid has not yet become sufficiently alkaline for passivation. The resulting pits may serve as mechanical stress points and concrete delamination sites, thus weakening reinforced concrete structures considerably.…”

“…The latter has been developed at the Institute of Physical Chemistry of the Russian Academy of Sciences and is positioned as a versatile (contact and migrating) corrosion inhibitor for concrete reinforcing steel [3][4][5][6][7][8].…”

Protective properties of the corrosion inhibitor of steel reinforcement in concrete IFKhAN–80

“…Он универсален и может использоваться и как контактный, и в качестве мигрирующего ингибитора. Его функциональные свойства подробно изучены в лабораторных и натурных условиях средней полосы [7][8][9][10][11][12][13]. Разработчики считают, что ИФХАН-80 может применяться, по крайней мере, для контактной защиты стальной арматуры в бетоне и в тропиках.…”