Enhanced Repair Techniques of Corroded Reinforced Concrete Short Columns

Abstract

Reinforcement corrosion in columns may be due to a variety of reasons. Corrosion products exert high pressure in the surrounding concrete, causing the cover to spall and thus exposing the steel reinforcements. This paper described the results of an experimental test for repairing weakened columns due to the corrosion of lateral and longitudinal steel. The repair was based on removing the corroded steel (longitudinal and lateral steel) while keeping the internal concrete core fit and repairing using steel-fiber concrete (FRC) jackets and various manufacturing techniques and maintaining a cross section similar to that of the original column section. The main objective of this work was to test the efficiency of different repair jackets, seeking the original column capacity without increasing the cross section. Two monolithic columns were used as control specimens, and 20 repaired columns were tested under axial load. The main variables in this work were the volume of the fraction of steel fibers in the concrete jackets, the size of the core, shear connectors, confinement of the internal core, and confinement of the full section. The effectiveness of repair methods was measured in terms of crack pattern and column strength. The study investigated the efficiency of FRC and confinement of the internal core for repairing the corroded columns, which results in higher axial resistance than in the original column. The stud shear connector proved ineffective in enhancing the original column’s axial load–carrying capability. To account for the concrete confinement stress in the repaired column, a mathematical approach was proposed. The load-carrying capacity calculated using the proposed method agreed well with the test results.