Estimation of rebar corrosion rate in reinforced concrete structure

Corrosion rate in reinforcing bars was investigated in this study. Seventy-two specimens were designed with 12 different target corrosion rates, two types of reinforcing bars, and 3 different concrete cover thickness. Corrosion current density, corrosion potential, and ohmic resistance of concrete were measured on these specimens using a Gecor device. Metal loss measurements were performed in accordance with ASTM G1-90, method C3.5, after specimens cracked. The actual corrosion weight loss of steel reinforcing bars was then compared to the result obtained from corrosion rate measurement. Finally, the estimation of corrosion rate could be made using electrical potential and current density measured. The experimental results showed that the actual corrosion levels of steel bars embedded in concrete are less than the targeted corrosion levels. Non-destructive corrosion measurement technique is applicable in order to assess corrosion level in reinforcing bars. This study suggested the relationship between corrosion rates, measured electrical potential and measured current density.