Long-Term Effectiveness of Cathodic Protection Systems on Highway Structures
Primary Topic: Pavement Maintenance
Description: Cathodic protection (CP), the technology used to mitigate corrosion of metals embedded in concrete, is the only rehabilitation technique that has been proven to stop corrosion in salt-contaminated bridge decks regardless of the chloride content of the concrete. This technology is based on the principle of applying an external source of current to counteract the internal corrosion current produced in reinforced concrete components. During CP, current flows from an auxiliary anode material through the electrolyte (concrete) to the surface of the reinforcing steel.
Various materials in various configurations are used as auxiliary anodes for CP resulting in various types of CP systems. The selection of the anode material and its configuration is paramount to the success of the system. The primary objective of this 5-year study was to determine the effectiveness of various materials and configurations when they are used as auxiliary anodes on highway structures during a long-term evaluation.
The findings of the study summarize the protection provided by the systems evaluated and estimate the expected service life for the anode materials in similar environments. This report will be of interest to engineers involved in bridge design, bridge performance evaluation and prediction, and bridge maintenance and rehabilitation.
FHWA Publication Number: FHWA-RD-01-096
Publication Year: 2001