Reinforced concrete is inherently a durable and nearly maintenance-free construction material under normal conditions. However, contemporary society's demands or harsh environmental conditions can cause deterioration of the material. For example, heavy and continual application of deicing salts during the winter months results in severe and rapid deterioration of bridge decks. Some reinforced concrete bridge decks with an expected service life of 25 to 50 years have required replacement after only 5 to 10 years.
The process of corrosion in a bridge deck begins when the deicing salt dissolves in the melted ice and penetrates to the level of the reinforcing bars. Chloride contained in the salt plus oxygen cause rusting of the bars. The rust expands and occupies a greater volume than the original steel and eventually causes cracking of the concrete. Then general spalling occurs or potholes form in the bridge deck surface. Once corrosion of the bars has cracked the concrete, more chloride enters to attack the bars, and deterioration of the reinforced concrete bridge deck is accelerated.
Epoxy-coated reinforcing bars are a viable and cost-effective corrosion-protection system for reinforced concrete structures. Before specifying a corrosion-protection system, the engineer or architect should carefully evaluate the particular structure's requirements for such a system, and its potential benefit-cost ratio. This article presents basic technical information on epoxy-coated reinforcing bars in a question and answer format.