Axial Compression Capacity of Concrete Columns Reinforced With Corrosion-Resistant Metallic Reinforcement

Abstract Axial compression performance of concrete columns reinforced with 2304 duplex stainless bars and spirals, carbon steel bars and spirals, and 316L stainless steel clad bars, in varying combinations is examined when the columns are exposed to corrosion. Two groups of columns were investigated: a control group, and a group submerged in a 5.0% by weight chloride solution subjected to accelerated corrosion. A relatively high corrosion rate of 8.5 μA/mm2 was used. After 60 days of corrosion the columns were tested to failure under axial compression. In terms of mass loss per unit of corrosion energy, columns reinforced with stainless steel spirals and either solid stainless or stainless clad vertical bars were 197% more corrosion resistant than carbon steel. Bars made with 2304 stainless steel and 316L stainless clad materials developed localized pitting corrosion that led to degradation of the concrete cover and a larger drop in axial compression than carbon steel reinforced columns. However, the all-carbon steel reinforced columns reached lower failure displacements and a corroded carbon steel reinforced column was the only column to experience sudden failure prior to reaching its theoretical maximum axial compression capacity. Axial compression capacity of the columns in both the control and corroded conditions was modeled using concrete confinement models that produced very good agreement with the experimental results.