Corrosion of discontinuous reinforcement in concrete subject to railway stray alternating current

摘要

Alternating current (AC) traction power systems account for 64% of the UK electrified railway network. However, the investigation of stray AC induced corrosion in reinforced segmental lining tunnels is still very limited. Electrochemical modelling and numerical simulation, validated by the experimental data, indicate that the severity of stray AC induced steel reinforcement corrosion mainly depends on the AC current density, frequency and the chloride content in concrete. Concrete containing discontinuous steel fibres has an inherent corrosion resistance to stray AC attacks due to the electrical double layer developed on the steel surface; the presence of chloride ions in the concrete pore solution however reduces the corrosion resistance. Special attention is therefore needed for steel fibre reinforced concrete (SFRC) subjected to AC current in the presence of high concentration chloride.