Effects of Corrosion on Stress-Strain Behavior of Confined Concrete

An analytical model is proposed to predict the stress-strain relationship of confined concrete subjected to reinforcement corrosion. The stress-strain graph of confined concrete with corroded reinforcement was predicted using estimation of four key parameters: maximum compressive stress, strain at maximum compressive stress, modulus of elasticity of concrete, and ultimate compressive strain of concrete. To validate the model, analytically predicted stress-strain curves of confined concrete of circular RC columns damaged due to corroded reinforcement were compared with those obtained from full-scale experimental tests with varying degrees of corrosion. The results of the comparison indicate good agreement. The RC columns had identical size, the same longitudinal steel reinforcement and spiral confinement type but with different spiral pitches providing varying levels of confinement. The corroded RC columns were categorized into four corrosion groups: noncorroded, low corrosion, high corrosion, and mechanical pitting corroded. The presented model is based on a modified version of the Mander's universal model for RC columns. (C) 2021 American Society of Civil Engineers.