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http://dx.doi.org/10.5574/KSOE.2016.30.4.327

Effect of Period of Immersion on Corrosion Potential, Anodic Polarization, and Impedance Characteristics of Reinforced Steel in Mortar (W/C: 0.6)  

Jeong, Jae-Hyun (Dept. of Mechanical & Energy System Engineering, Korea Maritime and Ocean Univ.)
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.)
Lee, Myeong-Hoon (Dept. of Marine System Engineering, Korea Maritime and Ocean Univ.)
Baek, Tae-Sil (Dept. of Steel Industry, Pohang College)
Publication Information
Journal of Ocean Engineering and Technology / v.30, no.4, 2016 , pp. 327-333 More about this Journal
Abstract
Reinforced concrete structures have found wide usage in land and maritime applications. However, the corrosion of reinforced concrete has been recognized as a serious problem from economic and safety standpoints. In previous studies, the corrosion behavior of the inner steel bar embedded in mortar (W/C: 0.4, 0.5) was investigated using electrochemical methods. In this study, multiple mortar test specimens (W/C: 0.6) with six different cover thicknesses were prepared and immersed in flowing seawater for five years. Subsequently, equations related to the cover thickness, period of immersion, and corrosion characteristics of the embedded steel bar were evaluated using electrochemical methods. Prior to immersion, the corrosion potentials indicated an increase with increasing cover thickness, and after five years, all corrosion potentials demonstrated a trend in the positive direction irrespective of the cover thickness. However, the relationships between the corrosion potential and cover thickness were not in complete agreement. Furthermore, after five years, all of the corrosion potentials indicated values that were nobler compared to those obtained prior to immersion, and their corrosion current densities also decreased compared to their values obtained prior to immersion. It was considered that the embedded steel bar was easily corroded because of the aggression of water, dissolved oxygen, and chloride ions; a higher W/C ratio also assisted the corrosion process. The corrosive products deposited on the surface of the steel bar for five years cast a resistance polarizing effect shifting the corrosion potential in the nobler direction. Consequently, it was considered that the W/C ratio of 0.6 showed nearly same results as those of W/C of 0.4 and 0.5. Therefore, the corrosion potential as well as various parameters such as the cover thickness, period of immersion, and W/C ratio must be considered at once for a more accurate evaluation of the corrosion property of reinforced steel exposed to marine environment for a long period.
Keywords
Reinforced concrete; Corrosion potential; Mortar; Electrochemical method; Cover thickness; W/C;
Citations & Related Records
Times Cited By KSCI : 4  (Citation Analysis)
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