Research Articles | Challenge Journal of Concrete Research Letters

Corrosion of steel bars in saturated Ca(OH)2 and concrete pore solution

Amir Poursaee

Abstract


Testing steel in solution has the advantage of avoiding the long time necessary for chlorides to penetrate the concrete cover.  It is well known that steel in high alkaline environments is passive and the protective capability of the passive film increases with pH.  The pH of saturated calcium hydroxide solution is lower than concrete pore solution which does induce passivation but not to the degree encountered by steel in good quality concrete.  Nevertheless, saturated calcium hydroxide has been used in many studies of rebar corrosion as a substitute for pore solution.  This paper discusses the electrochemical behavior of low carbon steel bars is chloride free and chloride contaminated pore solution and saturated calcium hydroxide solution.  Results show that the passive film on the steel immersed in pore solution and saturated Ca(OH)2 have similar composition.  However, as a result of lower pH in saturated Ca(OH)2 solution, the passive layer formed in this solution is less protective and does not offer enough passivity to steel to simulate a realistic concrete environment.

Keywords


pore solution; corrosion; Ca(OH)2; raman spectroscopy; cyclic polarization; linear polarization resistance

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References


Andrade C., Merino P., Novoa X. R., Perez M. C., Solar L. Passivation of reinforcing steel in concrete. Materials Science Forum 1995;192-194:861.

Hansson C. M. Comments on electrochemical measurements of the rate of corrosion of steel in concrete. Cement and Concrete Research 1984;14:574.

Ramirez E., Gonzalez J. A., Bautista A. The protective efficiency of galvanizing against corrosion of steel in mortar and in Ca(OH)2 saturated solutions containing chlorides. Cement and Concrete Research 1996;26:1525.

Hou J., Chung D. D. L. Effect of admixtures in concrete on the corrosion resistance of steel reinforced concrete. Corrosion Science 2000;42:1489.

Gonzalez J. A., Miranda J. M., Otero E., Feliu S. Effect of electrochemically reactive rüşt layers on the corrosion of steel in a Ca(OH)2 solution. Corrosion Science 2007;49:436.

Nakayama N. Inhibitory effects of nitrilotrin(methylenephosphonic acid) on cathodic reactions of steels in saturated Ca(OH)2 solutions. Corrosion Science 2000;42:1897.

Nakayama N., Obuchi A. Inhibitory effects of 5-aminouracil on cathodic reactions of steels in saturated Ca(OH)2 solutions. Corrosion Science 2003;45:2075.

Gonzalez J. A., Cobo A., Gonzaalez M. N., Otero E. On the effectiveness of realkalisation as a rehabilitation method for corroded reinforced concrete structures. Materials and Corrosion 2000;51:97.

G. Blanco, A. Bautista, H. Takenouti. EIS study of passivation of austenitic and duplex stainless steels reinforcements in simulated pore solutions. Cement & Concrete Composites 2006;28:212.

Lide D. R. CRC Handbook of chemistry and physics. New York, NY: CRC Press, 1999.

Verink E. D., Pourbaix M. Pitting potentials versus pH. Corrosion 1971;27:495.

Poursaee A., Hansson C. M. Reinforcing steel passivation in mortar and pore solution.

Cement and Concrete Research 2007;37:1127.

ASTM. C876-09: Standard Test Method for Half-cell Potentials of Uncoated Reinforcing Steel in Concrete. vol. 03.02. 2009. p.446.

Poursaee A. Automatic system for monitoring corrosion of steel in concrete. Advances in Engineering Software 2009;40:1179–1182.

Dunn D. S., Bogart M. B., Brossiaand C. S., Cragnolino G. A. Corrosion of iron under alternate wet and dry conditions. Corrosion 2000;56:470.

Balasubramaniam R., Kumar A. V. R., Dillmann P. Characterization of rust on ancient Indian iron. Current Science 2003;58:1546.

Dunnwald J., Otto A. An investigation of phase transitions in rust layers using Raman spectroscopy. Corrosion Science 1989;29:1167.

Oh S. J., Cook D. C., Townsend H. E. Characterization of iron oxides commonly formed as corrosion products on steel. Hyperfine Interactions 1998;112:59.

Miserque F., Huet B., Azou G., Bendjaballah D., L’Hostis V. X-ray photoelectron spectroscopy and electrochemical studies of mild steel FeE500 passivation in concrete simulated water. Journal de Physique IV 2006;136:89.

ImageJ. National Institutes of Health, http://rsbweb.nih.gov/ij/.

ASTM. G1-90: Standard Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens. ASTM, 1999.


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