Galvanic cathodic protection of corroded reinforced concrete structures

Vector Corrosion Technologies, Winnipeg, Manitoba, Canada

^* Corresponding author: davidw@vector-corrosion.com

Abstract

Reinforced concrete structures can be designed and maintained to achieve long service lives, even in aggressive chloride environments. Unfortunately, many structures, such as bridges, piers, and wharves, show signs of active corrosion (e.g. rust staining, concrete spalling, etc.) in as little as 5 to 10 years. Left unchecked, chloride induced corrosion can lead to major structural problems. Many severely corroded structures have been replaced at great expense and with significant disruption to the public. As an alternative to demolition and replacement, a viable option is to repair and protect severely deteriorated structures utilizing a galvanic encasement that both structurally upgrades and catholically protects the structure. This approach can provide an effective, low maintenance galvanic cathodic protection solution for deteriorated concrete structures. Galvanic encasements consist of distributed galvanic anodes embedded in a concrete overlay or concrete jacket. The galvanic encasement may include additional reinforcing steel to create a one-step structural repair and protection system. This paper presents case studies on the use of galvanic encasements to repair and protect reinforced concrete structures. Long term monitoring of field projects over more than 10 years indicates that effective cathodic protection can be provided for 20 to 40+ years.