Comparative study on the use of SHCC, HPFRC, and GFRP for enhancing the axial performance of RC columns with reduced reinforcement capacity

Corrosion-induced deterioration of reinforced concrete columns is a major concern in aging infrastructure, often leading to reduced load-carrying capacity and structural safety. This study investigates the structural performance of corroded reinforced concrete (RC) columns and evaluates the effectiveness of various strengthening techniques in restoring their load-bearing capacity. Corrosion-induced deterioration is simulated in RC columns, which are then strengthened using Strain-Hardening Cementitious Composites (SHCC), High-Performance Fiber-Reinforced Concrete (HPFRC), and Glass Fiber Reinforced Polymer (GFRP) reinforcement. The strengthening techniques incorporate embedded welded wire mesh and Near-Surface Mounted (NSM) steel or GFRP bars to enhance both strength and ductility. Experimental testing is conducted on eleven RC columns, divided into five groups to evaluate the impact of different strengthening configurations. The results indicate significant improvements in ultimate load capacity, energy absorption, and failure modes, with HPFRC and GFRP reinforcement showing enhanced performance compared to SHCC. The proposed strengthening systems led to significant performance enhancements, with ultimate load-carrying capacity increasing by up to 45 % and energy absorption improving by more than 60 % compared to unstrengthened specimens. A numerical model using the Finite Element Method (FEM) is developed and validated against experimental data. The FEM validation confirms strong agreement between numerical and experimental results, with an average ultimate load prediction accuracy of 95 %. A parametric study investigates the impacts of internal reinforcement diameter and steel mesh layers on load capacity. results indicate that strengthening effectiveness decreases with larger reinforcement diameters and that the benefit of additional steel mesh layers follows a nonlinear trend, plateauing beyond nine layers. The results provide valuable insights for optimizing strengthening strategies in deteriorated concrete structures.