Strain rate effect on properties of rubberized concrete confined with glass fiber-reinforced polymers

Abstract

Rubberized concrete possesses viscous damping that is higher than that of conventional concrete, making it a promising candidate for construction in high seismic regions. Confining rubberized concrete with glass fiber-reinforced polymers (GFRP) may result in superior performance. This paper investigates the behavior of rubberized-concrete-filled fiber-reinforced polymer tubes (RCFFT) under different strain rates. The rubberized concrete had 0, 10, and 20% volume replacement of fine aggregate with shredded rubber. Each test specimen's behavior was compared to that of conventional concrete-filled fiber-reinforced polymer tubes (CFFT). The GFRP tubes were fabricated using wet-layup with different numbers of GFRP layers. Three different strain rates (representing static, earthquake, and severe earthquakes) were used to test these specimens under cyclic axial loading. The RCFFT behaved in a manner that was similar to conventional CFFTs. The rubberized concrete's confinement limited the reduction in the confined compressive strength more than it did in the unconfined compressive strength. The confinement of both conventional and rubberized concrete resulted in an increase in both the compressive strength and the ductility. The increase in the strain rate by two and three orders of magnitude resulted in increases in the compressive strength and ductility of both the CFFT and RCFFT. High increases in the modulus of elasticity of both CFFT and RCFFT were observed with the increase of strain rates. The strain rate changed the behavior of the concrete that was confined with a lower confinement ratio. This effect was reduced when the confinement ratio was increased. The plastic dilation was also investigated. The addition of rubber resulted in a smooth transition in the dilation of concrete.