Tensile property analysis of carbon/glass hybrid fibers-reinforced graphene-modified polymer bars

Abstract

The application of single-type fiber-reinforced polymer (single-FRP) bar in civil engineering is restricted due to the brittle failure and low tensile modulus. In this work, the carbon/glass hybrid fibers-reinforced polymer (C/G-HFRP) bars were designed to realize tensile ductility and improve tensile modulus. Also, graphene nanosheets (GNPs) were used to modify the fracture toughness of polymer matrix between fibers, which can resist the energy release rate during the failure of carbon fibers and the crack initiation and development inside the modified C/G-HFRP bars. The experimental results indicated that GNPs increased the cooperative ability between fibers and reduced the separation degree of glass fibers after the failure of carbon fibers. The tensile strength and strain of the modified C/G-HFRP bars at the initial failure of carbon fibers were averagely improved by 6.9% and 4.3% relative to those of the unmodified ones, while their ultimate tensile strength and strain were averagely increased by 7.1% and 7.1%, respectively. Meanwhile, four evaluation indicators were proposed to reflect the superior performance of the modified C/G-HFRP bars. Additionally, the experiments verified that the contribution of carbon fibers to the secondary stiffness at the strain hardening stage in the tensile stress–strain response of the modified C/G-HFRP bars can be omitted.