Numerical investigation on the flexural behavior of geopolymer concrete beam reinforced with different types of fiber-reinforced polymer bars

Abstract

Concrete is a highly versatile and durable building material. The risk of greenhouse gas emissions and the subsequent environmental deterioration associated with the use of concrete has prompted research on concrete substitutes. Geopolymer concrete (GPC) reinforced with fiber-reinforced polymer (FRP) rebars has gained acceptance as FRP rebars typically possess more tensile strength and are corrosion-resistant compared to steel. The commonly used FRP rebars are Carbon FRP (CFRP), Glass FRP (GFRP), Aramid FRP (AFRP), and Basalt FRP (BFRP). Though research has been done on GPC reinforced with CFRP, GFRP, and BFRP rebars; work has yet to be explicitly reported on GPC reinforced with AFRP. Furthermore, comparative studies on the flexural strength of GPC beams reinforced with different FRP rebars are not available, which calls for additional research on GPC reinforced with various FRPs. This paper compares the flexural behavior of GPC beams reinforced with various FRP bars by performing a nonlinear finite element analysis using Abaqus. The different material constitutive models and parameters of concrete and FRP rebars are analyzed to model their complex nature in Abaqus. The load-deflection behavior and the failure modes of these beams are studied by simulating a four-point bending test in Abaqus. Different parametric studies are conducted on GPC with FRP rebars by varying the parameters of concrete and reinforcements. The results indicate that among the four FRPs considered in this study, CFRP bars performed better for tensile reinforcement, while steel stirrups showed better results for shear reinforcement. As there are no specific design standards for FRP-reinforced GPC beams, these results may be successfully applied to modifying the existing standards.