A Comparative Laboratory Study of Metallic Reinforcing Steels for Corrosion Protection of Reinforced Concrete Bridge Structures

This report presents study findings related to corrosion resistance of 12 types of metallic reinforcing steel bars. The accelerated laboratory corrosion testing was performed using eight large-scale concrete slabs that simulated typical reinforced concrete bridge decks for about 18 mo by an accelerated corrosion testing protocol followed by a detailed autopsy of extracted bar samples and acid-soluble chloride concentrations determined at the bar imprints. The weekly corrosion testing protocol consisted of a 3-d wetting cycle in 15 weight percent chloride solution at 77°F and a 4-d drying cycle at 100°F.\n\n\nThe best corrosion performance group of reinforcing bars includes epoxy-coated reinforcing steel, dual-coated reinforcing steel, stainless steel–clad reinforcing steel, and duplex solid stainless reinforcing steel with 23 percent chromium. The intermediate corrosion performance group includes duplex solid stainless reinforcing steel with 21 percent chromium, austenitic solid stainless reinforcing steel, another type of stainless steel–clad reinforcing steel, ferritic solid stainless reinforcing steel with 12 percent chromium, high-strength micro-composite reinforcing steel, and hot-dip galvanized reinforcing steel. The poorest corrosion performance group includes black steel and lean duplex solid stainless reinforcing steel with 12 percent chromium.\n