Strengthening reinforced concrete beams using GFRP rebars

Abstract

This research examines the flexural behavior of reinforced concrete beams reinforced with Glass Fiber Reinforced Polymer rebars. Five beams made of M20 grade concrete, each 150 mm by 200 mm by 1300mm, were examined by an experimental procedure.  GFRP rebars were incorporated into a matrix of high-strength polymer cement mortar to improve their structural integrity. A single beam acted as a control specimen, incorporating conventional steel reinforcement, whereas the other four beams were externally reinforced with GFRP rebars, varying in diameter and number. Before strengthening, the tension surfaces of the beams were prepared by chipping and roughening, after which a 30 mm thick layer of polymer-modified mortar was applied to secure the GFRP rebars. Configurations of two 4.5 mm rebars, four 4.5 mm rebars, two 6 mm rebars, and four 6 mm rebars made up the strengthening arrangements. Standard tests for materials and workability were performed prior to casting, and flexural strength tests were conducted on all specimens. Based on load-carrying capability, deflection, fracture formation, and failure patterns, the strengthening's efficacy was evaluated. The findings indicate that GFRP rebars significantly improve the flexural performance of RC beams, suggesting their potential utility in structural retrofitting.