Axial behaviour of FRP-confined rubberised concrete: An experimental investigation

Abstract

This paper investigates the axial behaviour of square and circular concrete specimens confined by externally bonded Fibre Reinforced Polymer (FRP) jackets. Axial compression tests were performed on 96 regular and rubberised concrete specimens. The parameters considered were rubber content (0% and 60%), section shape (circular and square), FRP type (Carbon or Aramid) and the number of FRP layer (1, 2 and 3). The behaviour of the specimens in both axial and lateral directions, as well as their dilation characteristics, were investigated. The test results indicate that the confinement effectiveness of Aramid-FRP is better than that of Carbon-FRP. It is also shown that the detrimental effect of sharp corner on confinement effectiveness is less critical when using high rubber content as the element can develop large lateral expansion at unprecedented axial deformation. Large axial deformations can enable the development of highly ductile concrete elements. Existing design-oriented models fail to predict the behaviour of confined rubberised concrete with rectangular cross-section, indicating the need for developing more refined confinement models.