Effect of Gfrp Fibres Recovered from Decommissioned Wind Turbine Blades on the Fracture Properties of Concrete

Abstract

Glass fibre-reinforced polymer (GFRP) from decommissioned wind turbine blades is expected to improve the fracture toughness of concrete. Based on this, the effect of different lengths and dosages of discarded GFRP fibres on concrete compatibility and compressive strength was explored. In addition, the fracture toughness of GFRP concrete (GFRC) beam was evaluated more visually by the three-point bending test coupling the digital image correlation (DIC) and acoustic emission (AE) techniques. Finally, scanning electron microscopy (SEM) and X-ray diffractometry (XRD) were used to reveal the reinforcement mechanism. The results showed that fibre incorporation decreased the compatibility of concrete by up to 54.69%; fibre lengths of 4cm and 6cm increased the compressive strength of concrete by up to 37.1%, while fibre lengths of 8cm decreased the compressive strength of concrete by up to 13.98%. The results of both AE and DIC tests demonstrated that increasing fibre length and doping induced an increase in the number and dispersion of microcracks within the GFRC, and concentrated near the crack development. In addition, the inclusion of fibres significantly improved the fracture toughness of concrete, for the fracture energy also increased, of which GFRC8-1.5 fracture energy is the largest, is 7.76 times that of the plain concrete. The microscopic test results indicated that the GFRP fibres have both a strong alkali resistance and a good synergy with the cement matrix. This study provides some theoretical guidance for the feasibility of application in recycled wind turbine blade concrete.

Keywords: Glass fibre-reinforced polymer concrete, Fracture toughness, Acoustic emission, Digital image correlation.