Long-Term Performance of Hybrid Anodes for Cathodic Protection of Reinforced Concrete

Abstract

The long-term performance of hybrid anode corrosion protection systems (UK invention disclosed in Patent GB2426008B) was investigated on six bridge structures as part of a holistic approach to corrosion risk management, using the performance criteria in ISO BS EN 12696:2016. The aim of the study was to review the effectiveness of current design approaches to meet the residual service life when the anodes are operating in the galvanic phase. This was achieved by analysing data on the general condition of the structures, the ongoing performance of the installed hybrid anodes, and assessing the subsequent corrosion risk. It was found that the six structures were generally in good condition, 1 to 8 years after refurbishment works, with low associated corrosion risk in areas protected by the hybrid anode systems. This is a positive finding for the wider implementation of hybrid anode systems as an alternative corrosion management technique. The reinforcement in the protected areas remained predominately in a passive condition, with calculated corrosion rates below the ISO 12696:2016 recommended threshold of 2mA/m2.