몰타르 시험편(W/C:0.4) 내부철근의 분극특성에 미치는 재령년수의 영향

Abstract

The structures of reinforced concrete has been extensively increased with rapid development of industrialsociety. Futhermore, these reinforced concretes are easy to expose to severe corrosive environments suchas sea water, contaminated water, acid rain and seashore etc.. Thus, corrosion problem of inner steel barembedded in concrete is very important in terms of safety and economical point of view. In this study,multiple mortar test specimen(W/C:0.4) with six types having different cover thickness each other was preparedand was immerged in seawater solution for five years to evaluate the effect of cover thickness and immersionyears to corrosion property of embedded steel bar. And the polarization characteristics of these embeddedsteel bars was investigated using electrochemical methods such as measuring corrosion potential, cathodicpolarization curve, and cyclic voltammogram. At the beginning of immersion, the corrosion potentials exhibitedincreasingly nobler values with increasing cover thickness. However, after immersed for 5 years, the thickercover of thickness, the corrosion potentials shifted in the negative direction, and the relationship betweencorrosion potential and cover thickness was not in good agreement with each other. Therefore, it is consideredthat the thinner cover of thickness, corrosive products deposited on the surface of the embedded steel barplays the role as a resistance polarization which is resulted in decreasing the corrosion rate as well asshifting the corrosion potential in the positive direction. As a result, it seemed that the evaluation whichcorrosion possibility of the reinforced steel would be estimated by only measuring the corrosion potentialmay not be a completely desirable method. Therefore, it is suggested that we should take into accountvarious parameters, including cover thickness, passed aged years as well as corrosion potential for moreaccurate assessment of corrosion possibility of reinforced steel which is exposed to partially or fully inmarine environment for long years.