Mechanical properties of green recycled fibre brazing reinforced hydraulic concrete for wind turbine blades

Abstract

To address the challenges associated with the green recycling and reuse of blades(Glass Fiber Reinforced Polymer, GFRP) in the widespread use of wind turbines and their continuous capacity iteration processes, decommissioned wind turbine blades were processed into fiber rods through mechanical method, and their feasibility of application in hydraulic concrete was verified. Macroscopic, microscopic, and acoustic emission(AE) method were employed to investigate the effects of different fiber rod lengths and dosages on the workability, compressive strength, flexural strength, and fracture damage of concrete. The result indicate that a 60 mm-long fiber rod with a 0.5% volume dosage maximally enhanced the compressive strength of concrete by 21.35%, while an 80 mm-long fiber rod with a 1.5% volume dosage reduced the compressive performance by 10.42%. The flexural strength of concrete was enhanced by varying degrees ranging from 21.93% to 105.6%. AE signals revealed that the number of acoustic emission events significantly increased with the increase in fiber length and dosage, and these events were concentrated near the mid-span and cracks. Additionally, the fracture surfaces were uneven, and the cracks appeared more tortuous. Therefore, the mechanical bonding between the recycled fiber rods of wind turbine blades and the cement matrix is effective, exhibiting a strong bridging function. The feasibility of their application in hydraulic concrete is strong, and it is foreseeable that their large-scale recycling and utilization hold broad development prospects.

Keywords

fibre-reinforced concrete / green recycling / mechanical properties / fracture damage / influencing factors / fan blades / concrete / acoustic emission