Behavior of axially loaded plain and fiber-reinforced geopolymer concrete columns with glass fiber-reinforced polymer cages

In this study, the behavior of axially loaded plain and fiber-reinforced geopolymer concrete columns reinforced with glass fiber-reinforced polymer (GFRP) bars and helices was investigated. Ten ambient-cured geopolymer concrete columns of 160 mm diameter and 640 mm height were cast and tested under concentric axial loads. The behavior of the columns was investigated under the effect of the type of reinforcement (steel vs. GFRP), pitch of the GFRP helices (40, 75, 100 mm), and addition of nonmetallic fibers, that is, glass fiber and polypropylene fiber. It was found that GFRP bar reinforced geopolymer concrete column achieved less axial load, confinement efficiency, and ductility compared to the geopolymer concrete column reinforced with the same amount of the steel reinforcement. Overall, the reduction in the pitch of the GFRP helices enhanced the confinement efficiency, post-peak behavior, and ductility of the plain and fiber-reinforced geopolymer concrete columns. Also, the addition of fibers significantly improved the ductility of the GFRP bar reinforced geopolymer concrete columns.