Behavior of reinforcing steel and reinforced concrete undergoing stray current

Abstract

Currents flowing along paths not being elements of a purpose-built electric circuit, are called stray currents. Various types of reinforced concrete structures (such as viaducts, bridges and tunnels) in the neighborhoods of railways may be subjected to stray current leaking from the rails. In these cases the concrete pore solution acts as an electrolyte, and the reinforcing rebars (or pre-stressed steel wires) embedded in concrete act as conductors, which can “pick up” the stray current and can corrode. The understanding of stray current-induced corrosion of steel rebar in concrete still remains unclear, as it is challenging to inspect in detail the full scale of steel rebar, as embedded in concrete. Most of previous understanding and preventive measures for stray current corrosion refer to investigations or field tests on pipelines. Besides, it is difficult to rebuild or repair the structures under or near rail transits. All above reasons reflect that stray current corrosion of reinforced concrete structures is in need of more in-depth investigation and understanding. As an expansion of the current body of knowledge of stray current corrosion of steel rebar in cement-based materials, this research aims to be a step forward towards for a better understanding of stray current corrosion mechanisms, a basis of feasible preventive measures for stray current-induced corrosion of reinforced concrete structures.