An experimental study on 3D printed concrete reinforced with fibers recycled from wind turbine blades

Abstract

The large-scale retirement and high recycling difficulty of wind turbine blades (WTB) pose great challenges to environment and society. To explore the practical applicability of recycled WTB in 3D printed concrete (3DCP), a systematic experimental study was conducted on the printability and physical-mechanical properties of 3DCP incorporating RWTB fiber. The distribution of RWTB fiber and porosity were analyzed using X-ray CT scan and Scanning Electron Microscopy, with the aim of unveiling the reinforcing and anisotropic mechanisms of 3DCP with RWTB fiber. The concrete with 3%–7% of RWTB fiber presented good extrudability and buildability, although slightly decreased the fluidity. Due to the directional effect and the layer-by-layer stacking process inherent in 3D printing, the RWTB fiber exhibited enhanced alignment along the printing direction, leading to modifications in the porosity. Incorporating 5% RWTB fiber in 3DCP significantly improved mechanical properties, with notable increases of 13.2%–29.9% in unconfined compressive strength and up to 147.4%–465.4% in bending toughness in the Y and Z loading directions, as compared to samples without fiber. Moreover, the mechanical anisotropy of 3DCP with RWTB fiber was less significant than that with the fiber having higher tensile strength, leading to a promising way to repurpose WTB and promote sustainability of 3DCP.