International Journal of Advanced Engineering Application

Axial Load-Carrying Capacity and Ductility Restoration of Corrosion-Damaged Reinforced Concrete Columns Confined with Fiber-Reinforced Polymer (FRP) Wraps

Author(s):Rohan Mehta, Komala Rao

Affiliation: Department of Civil Engineering, National Institute of Technology (NIT) Warangal, Telangana, India

Page No: 98-102

Volume issue & Publishing Year: Volume 3, Issue 6, 2026/06/14

Journal: International Journal of Advanced Engineering Application (IJAEA)

ISSN NO: 3048-6807

DOI:

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Abstract:
Reinforcement corrosion remains the predominant cause of premature deterioration in reinforced concrete (RC) columns exposed to chloride-laden environments, with corrosion-induced section loss, cover spalling, and bond degradation collectively reducing axial capacity and ductility well below original design values. Fiber-Reinforced Polymer (FRP) jacketing has emerged as a widely adopted external confinement technique for restoring and enhancing the structural performance of such columns, offering high strength-to-weight ratio, corrosion immunity, and minimal disruption to occupancy during retrofit. While the confinement mechanics of FRP-wrapped pristine columns are well established, the behaviour of FRP-confined columns with pre-existing corrosion damage — including the influence of reinforcement section loss and residual bond degradation on confined response — requires further systematic investigation under representative Indian coastal exposure conditions.
This study investigates the axial load-carrying capacity, stress-strain response, and ductility characteristics of corrosion-damaged RC columns (200 mm diameter, 1000 mm height) retrofitted with carbon FRP (CFRP) and glass FRP (GFRP) wraps. Six specimen groups were tested: an undamaged control, an accelerated-corrosion control (induced via impressed current to achieve approximately 12% mass loss in longitudinal reinforcement), and four corrosion-damaged specimens retrofitted with 1-layer CFRP, 2-layer CFRP, 2-layer GFRP, and 2-layer CFRP with an additional moisture-sealant interlayer. Properties evaluated include ultimate axial load, axial and hoop strain at failure, ductility index, stress-strain envelope under monotonic compression, and SEM-based examination of the FRP-concrete interface bond layer at failure.
The 2-layer CFRP retrofit restores 118% of the undamaged control's ultimate load (724 kN versus 612 kN) despite the underlying 12% reinforcement section loss, while the 2-layer CFRP with sealant interlayer achieves the highest capacity at 742 kN (+69.4% over the corroded control). The GFRP-retrofitted specimen exhibits the highest hoop rupture strain (1.42%) and ductility index (2.58), indicating superior deformability despite lower ultimate strength than CFRP. SEM examination of the interface reveals localised debonding initiating at corrosion-induced cover delamination sites, with the sealant interlayer specimen showing the most continuous bond layer at failure.

Keywords: FRP confinement, corrosion damage, reinforced concrete columns, axial capacity, ductility, CFRP, GFRP, stress-strain behaviour, structural retrofit, SEM, bond interface

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