What is cathodic protection in concrete repair?

Cathodic protection (CP) is an electrochemical technique used to halt corrosion in reinforced concrete. It works by connecting the steel reinforcement to a sacrificial anode (usually zinc) or an impressed current system. This setup forces the steel rebar to become the 'cathode' in an electrical cell, preventing it from losing electrons and rusting. It is particularly effective in chloride-contaminated structures like bridges or coastal buildings where removing all contaminated concrete is impossible. CP essentially 'switches off' the corrosion process.