Chloride Extraction and Realkalization of Reinforced Concrete Stop Steel Corrosion
Publication: Journal of Performance of Constructed Facilities
Volume 12, Issue 2
Abstract
Chloride extraction and realkalization are nondestructive, electrochemical treatments to halt and prevent corrosion in chloride-contaminated and carbonated concrete, respectively. The process actually removes chloride ions from the contaminated concrete by the principle of ion migration while at the same time raising the pH of the carbonated concrete through electro-osmosis. Concrete to be treated is first tested to determine the level of chloride contamination. Then, after preparing the surface, a steel or titanium mesh electrode is attached to the structure. The electrode is embedded in a nontoxic biodegradable electrolytic media. Next, electric contacts are established between the attached electrode and the steel reinforcement bars (rebars) inside the concrete. When an electric field is applied, chloride ions migrate away from the rebars and towards the externally attached electrode, eventually ending up in the temporary electrolytic media, which is then discarded. Simultaneously, alkali ions migrate from the electrolyte into the concrete, raising its pH to the original levels. The passivating layer of the rebars is thus reestablished to protect them from corrosion.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Bennet, J. E., and Schue, T. J. (1990). “Electrochemical chloride removal from concrete: a SHRP contract status report.”Corrosion 90, National Association of Corrosion Engineers, Houston, Tex.
2.
Bennet, J. E., and Schue, T. J. (1994). “Evaluation of the NORCURE process for electrochemical chloride removal from steel-reinforced concrete bridge components.” Strategic Highway Res. Program/ELTECH Res. Corp., Washington, D.C.
3.
Clemens, G. G., and Jackson, D. R. (1996). “Pilot applications of electrochemical chloride extraction on concrete decks in Virginia.”VTRC 96-IR3, Virginia Transportation Research Council, Charlottesville, Va.
4.
Kennedy, D., Miller, J. B., and Nustad, G. E. (1993). “Review of chloride extraction and realkalization of reinforced concrete.” Norwegian Concrete Technologies, Oslo, Norway.
5.
Manning, D. G., and Ip, A. K. C. (1994). “Rehabilitating corrosion damaged bridges through the electrochemical migration of chloride ions.” American Concrete Institute, Detroit, Mich.
6.
Miller, J. B., and Nustad, G. E. (1993). “Effect of electrochemical treatment on steel to concrete bond strength.”Proc., NACE Conf., National Association of Corrosion Engineers, Houston, Tex.
7.
“The NCT-method of concrete desalination.” (1992). NORCURE Publication, Norwegian Concrete Technologies, Oslo, Norway.
8.
“The NCT-method of concrete re-alkalization.” (1992). NORCURE Publication, Norwegian Concrete Technologies, Oslo, Norway.
9.
Slater, J. E., Lankard, D. R., Moreland, P. J. (1976). “Electro-chemical removal of chlorides from concrete bridge decks.”Mater. Perform., Nov.
10.
Whitmore, D. W. (1995). “Rapid electrochemical treatment of concrete: a new process can be used to stop chloride induced corrosion of bridge components.” Vector Construction, Ltd., Winnipeg, Manitoba, Canada.
Information & Authors
Information
Published In
Copyright
Copyright © 1998 American Society of Civil Engineers.
History
Published online: May 1, 1998
Published in print: May 1998
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.