Experimental study on the uniaxial compressive behaviour of a fibre reinforced polymer standing support

Laboratory tests were conducted to investigate the behaviour of an innovative fibre reinforced polymer (FRP) standing support subject to uniaxial compression. The FRP standing support consisted of two major components: 1) the internal cylindrical concrete column made of coal rejects and a cementitious grout, and 2) the external FRP jacket. A total of ten specimens with different water-to-cementitious grout (w/c) ratios and various layers of FRP confinement were prepared and tested. As expected, an increased w/c ratio adversely affected the compressive strength of the internal cylindrical column. The compressive strength of the column decreased from 15.9 MPa to 13.4 MPa when the w/c ratio increased from 1 to 1.2. Test results also indicated that the columns became much stronger and more deformable when confined with an FRP jacket. In contrast to the unconfined control specimens, the columns confined with two layers of FRP experienced an increase of approximately 150% in maximum compressive strength at approximately 500% higher axial deformation. A further growth in strength and deformability was also observed when the columns were confined with four layers of FRP. The maximum strength and deformability achieved were up to 49.6 MPa and 7.2% respectively.