Corrosion inhibitors in concrete repair systems

Abstract

Corrosion of reinforcing steel represents the most widespread form of deterioration of concrete structures. It affects reinforced concrete which is exposed to the effects of carbonation and/or to significant concentrations of chloride salts. Effective procedures employed in the past to combat reinforcement corrosion have required either extensive cutting out and replacement of contaminated but otherwise sound concrete at the level of the embedded steel or the use of electrochemical measures such as impressed-current cathodic protection. Over the past decade, however, the concrete repair industry has developed novel techniques that are claimed to restore the protective character of cover concrete by introducing corrosion inhibitors into the carbonated and/or chloride-contaminated material. As this approach requries only physically unsound or heavily contaminated regions of the concrete to be removed and reinstated it can involve reduced costs, pollution and inconvenience to owners and users of affected structures. This paper presents a critical review of current knowledge of various types of corrosion inhibitor treatment that are in use, or under consideration for use, in repair systems for concrete structures with corrosion problems resulting from carbonation and/or chloride salts.

Monitoring the corrosion and remediation of reinforced concrete on-site: An alternative approach

“…However, at this stage of the treatment, up to 30 months following MCI application, when compared to the control panel, corrosion rates (as judged by R P ) are apparently higher for samples treated with MCI. This apparent effect has also been found by other workers [16,17]. It should be noted that such MCI's are dependent for their action on diffusion processes [12] and it therefore may be some time before benefits from such a remediation strategy become apparent.…”

“…These ideas might be extended towards a suggestion that such an inhibitor would be much more efficient at delaying the onset of vigorous corrosion in a system subjected to mild attack than it might be in reducing the corrosion rate of an already severely corroding reinforcing bar. Such data may account for the fact that several researchers [16,17] have had trouble in identifying any positive effects of inhibitors in cases where Cl À has been admixed into the concrete mix or the exposure conditions have been too harsh. The work herein would suggest that in cases where the inhibitor is utilised in a role to delay the onset of corrosion, possibly as has been tested by its manufacturers, then it may appear to have the greatest possibility to do so.…”

Investigations of an ethanolamine‐based corrosion inhibitor system for surface treatment of reinforced concrete

“…Some of these involve the use of surface-applied corrosion inhibitors that are intended to penetrate the concrete cover to the reinforcing steel thus modifying the electrochemical behaviour of the metal [2,3]. Features of two inhibitor treatments of this sort have been reported elsewhere [4,5].…”

Effect of Electrical Injection of Corrosion Inhibitor on the Corrosion of Steel Rebar in Chloride-Contaminated Repair Mortar

“…Corrosion inhibitors can be added to the fresh concrete, dissolved into the water used for mixing [10,[12][13][14], or can be applied on the surface of the hardened concrete [11,[14][15][16]. In the latter case, the solution containing the inhibitor has to penetrate through the microstructure of hardened concrete towards the rebar.…”