What should be done with reinforcement bars that exhibit mill scale or light rust?

For reinforcement bars that exhibit mill scale or light rust, the appropriate action is to clean and use them. Mill scale is a thin layer of oxidation that forms on the surface of steel during the manufacturing process. Light rust, on the other hand, can occur due to exposure to moisture but does not usually indicate significant degradation of the material.

Cleaning the bars is essential as it removes the surface irregularities that can affect bonding with concrete. This cleaning process may involve wire brushing, sandblasting, or using other methods to ensure a clean surface that promotes proper bonding with the concrete. Once the bars are cleaned, they can be used effectively in concrete applications.

Rejecting reinforcement bars solely due to mill scale or light rust would be unnecessary and wasteful, given that these conditions can typically be remedied through proper cleaning processes. Therefore, the correct approach is to clean the bars and use them, ensuring they meet the necessary standards for performance in their intended application.