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http://dx.doi.org/10.14773/cst.2015.14.2.99

Effect of Passing Aged Years and Coating Thickness on Corrosion Properties of Reinforcing Steel in Mortar (W/C:0.5)  

Moon, Kyung-Man (Dept. of Marine Equipment Engineering, Korea Maritime and Ocean Univ.)
Lee, Sung-Yul (Dept. of Marine Equipment Engineering, Korea Maritime and Ocean Univ.)
Jeong, Jin-A (Dept. of Marine System Engineering, Korea Maritime and Ocean Univ.)
Lee, Myeong-Hoon (Dept. of Marine System Engineering, Korea Maritime and Ocean Univ.)
Baek, Tae-Sil (Dept. of Steel Industry, Pohang College)
Publication Information
Corrosion Science and Technology / v.14, no.2, 2015 , pp. 99-105 More about this Journal
Abstract
The structures of reinforced concrete have been extensively increased with rapid development of industrial society. Futhermore, these reinforced concretes are easy to expose to severe corrosive environments such as seawater, contaminated water, acid rain and seashore etc.. Thus, corrosion problem of steel bar embedded in concrete is very important in terms of safety and economical point of view. In this study, specimens having six different coating thickness (W/C:0.5) were prepared and immersed in flowing seawater for five years to evaluate the effect of coating thickness and immersion time on corrosion property. The polarization characteristics of these embedded steel bars were investigated using electrochemical methods such as corrosion potential, anodic polarization curve, and impedance. At the 20-day immersion, the corrosion potentials exhibited increasingly nobler values with coating thickness. However, after 5-yr. immersion their values were shifted in the negative direction, and the relationship between corrosion potential and coating thickness was not shown. Although 5-yr. immersion lowered corrosion potential, 5-yr. immersion did not increase corrosion rate. In addition, after 5-yr. immersion, the thinner cover thickness, corrosion current density was decreased with thinning coating thickness. It is due to the fact that ease incorporation of water, dissolved oxygen and chloride ion into a steel surface caused corrosion and hence, leaded to the formation of corrosion product. The corrosion product plays the role as a corrosion barrier and increases polarization resistance. The corrosion probability evaluated depending on corrosion potential may not be a good method for predicting corrosion probability. Hence, the parameters including cover thickness and passed aged years as well as corrosion potential is suggested to be considered for better assessment of corrosion probability of reinforced steel exposed to partially or fully in marine environment for long years.
Keywords
reinforced concrete; corrosion potential; anodic polarization; impedance; cover thickness; W/C;
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1 R. N. Swamy, S. Koyama, T. Arai, N. Kikami, Proceedings of the Durability of steel reinforecement in marine environment, SP 109-7, p. 1614, ACI, Nagoya, Japan (1989).
2 S. Ozaki, N. Sugata, Proceedings of the concrete in marine environment SP 109-26, p. 587, ACI, Nagoya, Japan (1989).
3 D. H. Jeon, K. M. Moon, T. S. Baek, and J. H. Jong, Corros. Sci. Tech., 21, 3 (1992).
4 S. D. Hong, Mater.Environ., 42, 462 (1993).
5 G. C. Jang, J. Conc. Soc. of Jpn, 32, 73 (1994).
6 S. D. Hong, Corros. Tech. of Jpn, 33, 462 (1984).
7 D. H. Jeon, K. M T. S. Baek and J. H. Kim, Corros. Sci. Tech., 21, 11 (1992).
8 K. G. Kim, B. H. Ryou, S. J. Kim, K. J. and K. M. Moon, J. Ocean. and Tec., 14, 23 (2000).
9 N. G. Thampson, K. H. Lawson, and J. A. Beavers, Proceeding of the Corrosion/87 Technique, p. 182, NACE, Houston (1987).
10 J. A. Apostoles, D. Park, and R. A. Carello, Proceedings of the corrosion/87Technique, p. 168, NACE, Houston (1987).
11 Y. R. Yoo, H. H. Cho, S. Take and J. G. Kim, Met. Mater. Int., 12, 255 (2006).   DOI   ScienceOn
12 K. M. Moon, J. P. Won, D. H. Park, S. Y. Lee, J. A. Jeong, M. H. Lee and T. S. Baek, Corros. Sci. Tech., 13, 20 (2014).   DOI   ScienceOn
13 J. A. Muylder, and M. Pourbaix, Atlas of Electrochemical Equilibrium in Aqueous solution Ed by M. Pourbaix, p. 313, Pergamon press, Texas (1966).
14 ASTM C876-80, Standard Test Method for Half-Cell Potentials of Uncoated Reinforcing Steel in Concrete (Withdrawn 2008), ASTM International, West Conshohocken, PA (1999).
15 Concrete Society of Japan, Protection Guide of Marine Concrete Structure(proposal), p. 10, Juridical Foundation, Tokyo (1984).
16 K. M. Moon, Practical Electrochemistry, p. 177, Hyosung publication Co. Ltd., Pusan (1999).