Epoxy coating and other protective measures for reinforceing steel embedded in concrete subjected to a chloride laden environment

Corrosion of steel reinforcement is the most significant factor in the deterioration of reinforced concrete structures. Corrosion of reinforcing steel in marine structures and bridges is initiated mainly by chloride contamination. When steel starts to corrode, the cross section of the reinforcing bar becomes smaller, also the volume of corrosion products exerts a pressure on the concrete resulting in spalling of the concrete cover and directly exposing the steel to the corrosive agents, thus accelerating the corrosion process and further reducing the load carrying capacity of the concrete member.;Although there are corrosion protective measures available to the concrete producer such as use of protective coatings on steel surface and use of corrosion inhibitors, a very limited amount of information exists on the comparative behavior of these common corrosion protection strategies in cracked concrete, especially in cracked high performance concrete (HPC).;The relative effectiveness of different protection methods for steel reinforcement such as the use of new types of epoxy-coated reinforcement, galvanized reinforcement, and corrosion inhibitors was investigated in concrete with water-to-cement ratios of 0.60 and 0.40 and 0.25. Concrete slabs were uncracked and had preformed transverse cracks. The effect of water-to-cement ratio and crack widths on the rate of corrosion in precracked reinforced concrete slabs also was investigated. Testing was performed in the laboratory and in the field. It was found that cracked HPC concrete alone or with addition of corrosion inhibitors cannot provide sufficient corrosion protection for uncoated steel reinforcement in a chloride-laden environment and that additional protection to the reinforcing steel in the form of epoxy coating is necessary to provide long-term service life of the concrete structure.