Corrosion in Reinforced Concrete

Corrosion of reinforcing steel is the predominant cause of failure in reinforced concrete structures leading to financial losses, safety risks and environmental impact.

The understanding of the mechanisms and kinetics of the degradation processes of concrete allows us to improve the design of structures to enhance durability and extend service-life.

Iron ore is mined from earth where it exists as oxides. It is refined in furnaces at high temperatures to make steel. Then it is protected and fabricated into different types of structures. However, throughout its life, steel is not stable and has the potential to oxidize and return to its original nature.

When embedded in concrete, steel is passivated by concrete’s high alkalinity making it resistant to corrosion. However, the ingress of chlorides and carbon dioxide from the environment break down this passive layer and initiate corrosion. The resulting corrosion product has a higher volume than steel creating stresses that cause the cracking and spalling of concrete leading to ultimate structural failure.