The feasibility of continuous basalt fibre-reinforced polymer application to composite cross-arms

Composite cross-arms have the advantages of high lightning resistance but impose onerous requirements on mechanical and insulation reliability. Traditional glass fibre composites fail to meet the needs of practical applications. Basalt fibre exhibits better mechanical properties and stability than glass fibre and has potential application value. This study aims to evaluate the feasibility of its application to composite cross-arms. The mechanical, electrical, and physical properties of basalt fibre-reinforced polymer (BFRP) were investigated and compared with glass fibre-reinforced polymer (GFRP). The results indicate that BFRP has better thermal stability and mechanical properties than GFRP. Among them, the temperature at the maximum weight loss rate of BFRP is 14 degrees C higher than that of GFRP, and the tensile and flexural modulus of BFRP is 43% and 29% higher than those of GFRP. Furthermore, the dielectric losses of BFRP and GFRP at 50 Hz are 2%, and the breakdown field strength is 22 kV/mm, both of which have the same insulation properties. BFRP meets the requirements of composite cross-arm for quality and reliability to ensure the safety and stability of transmission lines. However, the interlaminar shear test and SEM show weak interfacial bonding strength between basalt fibre and resin. Furthermore, micro-computed tomography scanning of BFRP and GFRP and 3D construction of their internal microstructures indicate that the pore defect content of BFRP reaches 0.034%, which far exceeds that of GFRP. These findings show that the wettability and adhesion between basalt fibre and resin must be improved. Developing special sizing agents for basalt fibre is necessary further to improve the mechanical and electrical properties of BFRP.