Title: Effect of Active Confinement on Compressive Behavior of Glass Fiber-Reinforced Polymer-Confined Expansive Concrete under Axial Cyclic Loading
Author(s): Qi Cao, Huan Li, and Zhibin Lin
Publication: Structural Journal
Appears on pages(s): 207-216
Keywords: confinement action; cyclic compression; expansive concrete; fiber-reinforced polymer; stress-strain relation
Fiber-reinforced polymer (FRP) tube-confined expansive concrete columns fully use the compressive properties of concrete and the tensile properties of FRP and it significantly increases the strength and ductility of concrete. To clearly understand the FRP-confined expansive concrete under earthquake load, the mechanical properties of glass fiber-reinforced polymer (GFRP) tube-confined expansive concrete (GCEC) under cyclic axial compression were studied. Different core concrete, loading patterns, and GFRP tube thickness were considered and compared. Test results show that the strength enhancement ratio and hoop rupture strain of GFRP-confined expansive concrete cylinders (GCECs) were improved compared with GFRP-confined unexpansive concrete cylinders (GCUCs). Additionally, the strength enhancement ratio of GCUC and the hoop rupture strain of GCUC and GCEC specimens under cyclic axial compression were higher than that under monotonic axial compression. In addition, it was found that expansion of core concrete has no significant effect on the plastic strain-envelope unloading strain relationship as well as stress degradation ratio. For the unloading/reloading path of GCEC, it indicates that the analytical results based on the existing models are in good agreement with the experimental values.