Residual compressive section capacity of filament wound carbon, glass, and basalt fibre-reinforced polymer tubes: Influence of elevated temperatures

This study investigates the residual compressive properties of various filament wound FRP tubes after exposure to elevated temperatures. Exposure temperature and fibre type were considered as the test variables. The experimental program included compression tests for BFRP, GFRP, and CFRP tubes at room temperature and after exposure to elevated temperatures up to 350 °C. A total number of 72 specimens were tested in compression. In addition, Differential Scanning Calorimetry, and Scanning Electron Microscopy were conducted on selected samples to investigate the thermal and microstructural properties of the tubes. The compressive strength of tubes, regardless of the fibre type, seemed to be affected by the competing effects of post-curing and resin matrix degradation. With respect to fibre type, for temperatures below 350 °C, BFRP exhibited the highest compression strength retention, whereas CFRP tubes showed the lowest strength retention. Temperature of 350 °C was found to be the critical temperature (the temperature that FRP loses 50 % of its load carrying capacity) for CFRP tubes, while the critical temperature for GFRP and BFRP tubes were respectively, somewhere lower than 350 °C. The maximum compressive strength reductions for BFRP, GFRP, and CFRP were 94 %, 63 % and 50 % respectively after exposure to 350 °C.