Measurements on macrocells made of segmented reinforcement in concrete showing environmental impacts on corrosion of steel in concrete

Abstract

Corrosion of steel in concrete can be characterized by measuring the galvanic current density when a macrocell is established. On nonpolarized steel, however, other electrochemical techniques like linear polarization resistance measurements may be used to characterize the electrochemical state of steel in concrete. On existing structures with their large dimensions and local differences in exposure conditions, local differences in the electrochemical state of the embedded reinforcement are established, leading to potential differences along the reinforcement and galvanic currents flowing. When it is possible to isolate anodic areas from the rest of the reinforcement, both galvanic current measurements, determination of polarization resistance on the separated anodic areas and the driving force between the anodic segments and the reinforcement are possible to obtain. In this work, this procedure is discussed and verified on a field structure on anodic areas caused by cracks in the concrete overlay and the results thereof are presented.