Assessment of residual strength of corrosion damaged concrete structures

Abstract

The corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. In addition, the residual strength of concrete with corroded reinforcement is much debated. This is because many parameters are implicated when assessing reinforcement corrosion, such as by using the percentage of loss of bar area, percentage of mass loss, reduction of bar radius, percentage of corroded area in the overall beam, and the width of the surface crack. The aim of the current study is to integrate correlations between deterioration and strength degradation into a systematic methodology for estimation of the residual strength of concrete structures based on their serviceability limit state. In the numerical analysis, the objective is to understand the effects of corrosion expansion on the behaviour of surface crack width. Results from the numerical study are used to determine parameters for the experimental investigation. The experimental approach is used to assess the influence of corrosion parameters, which are quantified as a percentage of the section loss, radius loss or corrosion penetration, and crack width on the residual bond strength based on different bar locations, casting positions, and impressed currents. Results from the experimental analyses show that the corrosion level on the main reinforcing bar in this study cannot be used as an indicator in assessing the residual bond strength due to many factors consideration during the assessment. However, corrosion-induced crack width on the bottom cast correlated well with residual bond strength. When crack width increased, most of the bar had a lower residual bond strength value.