Bond Properties between Concrete and Corrosion-Resistant Reinforcing Steels

Bond-slip characteristics of corrosion-resistant reinforcing steel bars embedded in concrete were determined with a beam-end test conducted in accordance with ASTM A944. The reinforcing steel bar types considered included solid stainless steel bars (316LN, N32, and 2205) and Grade 60 carbon steel bar with the exterior surface clad with 316L stainless steel (NX), epoxy-coated steel with a zinc undercoating, high-chromium heat-treated steel, and two control groups of ASTM A615 Grade 60 and Grade 75 steel. Observed beam-end test failure modes were yielding, concrete splitting, and pullout. Key conclusions are that bond strength and stiffness increased with increasing relative rib area, stainless steel had a lower pullout bond stiffness when compared to black ASTM A615 steel, and the presence of an epoxy coating decreased the adhesion strength but did not appreciably affect mechanical load-slip response or peak bond strength.