An evaluation on anti-corrosion performance of galvanized (zinc-coated) rebar in concrete by galvanostatic technique

Galvanized rebar is known to perform an anti-corrosion effect by sacrificial anodic reaction of zinc. Meanwhile, accelerated corrosion test by galvanostatic method has been used to evaluate corrosion and/or anti-corrosion property of the rebar in concrete. However, in using this test on galvanized rebar, the influence of applied current density has not yet been clarified. In this study, to investigate adequate test condition, various range of applied current density, which is 20∼230μA/cm², was tested on galvanized rebar embedded in concrete. As a result, galvanized rebar was found to perform the increase of polarization resistance (R_p) as the applied current density is lower. Furthermore, R_p showed the increasing behavior as corrosion has progressed. Moreover, the actual corrosion amount was shown smaller than the designed one by performing adequate anti-corrosion behavior. In conclusion, within 160μA/cm² was assumed to be appropriate in the scope of this study.