Axial compression capacity of concrete columns reinforced with corrosion-resistant metallic reinforcement

Abstract

Axial compression performance of concrete columns reinforced with 2304 solid stainless bars and spirals, carbon steel bars and spirals, and 316 L stainless steel clad bars is examined after the columns are exposed to severe 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 impressed current density of 8.5 μA/mm2 was used and after 60 days of accelerated 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 solid stainless steel and 316 L 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 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 good agreement with the experimental results.