Investigation of mechanical and degradation characteristics of filament-wound composite pipes incorporating basalt/E-glass hybrid reinforcement

This study investigates the mechanical (flexural and low-velocity impact test) and chemical (immersion degradation test) properties of basalt/E-glass hybrid fiber-reinforced polymer composite pipes (HFRP) fabricated by the filament winding technique. The HFRP composites composed of eight layers at constant fiber tension and the constant winding angle of ±55° for the basalt fiber and ±90° for the E-glass fiber were fabricated employing a 3-axis filament winding machine with a stage by stage curing process in the furnace. Eleven HFRP composite arrangements with fiber content proportions of 100 %, 25:75 %, 50:50 % and 75:25 % and various stacking sequences were studied. The study revealed that the fiber content ratio had a moderate influence on the mechanical properties, while the stacking sequence played a more significant role. Notably, the specific configuration designated as BGH7, which combined 50 % basalt fibers with 50 % E-glass fibers in a particular stacking order, exhibited superior performance. BGH7 demonstrated a remarkable 39.2 % increase in flexural strength compared to the E-glass FRP composite. Additionally, it showed improved resistance to low-velocity impacts at different energy levels: 60.52 % improvement for 20 J, 5.684 % for 30 J, and 21.30 % for 40 J. The BGH7 configuration also displayed superior resistance to chemical degradation. Compared to the E-glass pipes, BGH7 showed a significant improvement in withstanding exposure to NaCl by 33.48 %, HCl by 70.21 %, and H2SO4 by 114.78 %. This research suggests that the arrangement of basalt and E-glass fibers, particularly the BGH7 configuration, can significantly enhance the mechanical and chemical resistance of HFRP pipes compared to using E-glass fibers alone. The damage analysis was carried out using scanning electron microscope (SEM) and ultrasonic scan techniques.