Evaluation of Corrosion-Resistant Steel Reinforcement

The corrosion of steel reinforcement in an aging highway infrastructure is a major problem currently facing the transportation engineering community, in particular bridge engineers. In the United States, maintenance and replacement costs are measured in billions of dollars. Further, the use of deicing salts has resulted in steady deterioration of bridge decks due to corrosion. These concerns have initiated continual development of protective measures. Application of carbon fiber reinforced polymer or corrosion-resistant steel reinforcement for the replacement of existing mild steel reinforced concrete bridge decks has great potential due to the inherent corrosion resistant properties associated with the material. To investigate corrosion prevention through the use of corrosion-resistant alloys, MMFX Microcomposite steel reinforcement, a high-strength, high chromium steel reinforcement, is evaluated for corrosion resistance performance. The steel is compared to epoxy-coated and uncoated mild steel reinforcement. Principal emphasis is placed on corrosion performance of the steel, which is evaluated using ASTM and Rapid Macrocell accelerated corrosion tests. Ongoing research study at Iowa State University will determine if MMFX Microcomposite steel reinforcement provides superior corrosion resistance to epoxycoated mild steel reinforcement in bridge decks. After 12 weeks, the associated ASTM ACT corrosion potentials indicate neither MMFX Microcomposite nor epoxy-coated mild steel reinforcement steel have undergone active corrosion. However, the uncoated mild steel underwent active corrosion with the second week. Within the second week, Rapid Macrocell ACT produced severe corrosion risk potentials for all reinforcement types.