Low-Strength Concrete with Raw-Crushed Wind Turbine Blade and Coarse Recycled Aggregate

Abstract

Nonselective crushing of wind turbine blades results in raw-crushed wind turbine blade (RCWTB), a material that can be used in concrete production. Wind farm decommissioning can also generate coarse recycled aggregate (CRA) from the demolition of wind turbine concrete footings. This paper proposes a first approach for the joint management of both wastes through their simultaneous use in low-strength concrete, with a target compressive strength of 25 MPa. Mixes with 50% and 100% CRA, and 0% and 10% RCWTB as a cement addition, were designed, with the effect of CRA content not being statistically significant, to analyze its interaction with RCWTB. The results showed that, on the one hand, RCWTB reduced strength and stiffness under compression by a maximum of 9%–15%, although the target strength was achieved in all mixes; the presence of balsa wood and polymer particles in RCWTB, with high flexibility, could explain these reductions. On the other hand, the stitching effect of the glass fiber–reinforced polymer fibers present in RCWTB largely improved the bending-tensile mechanical properties. For example, flexural strength was almost doubled (from 2.51 to 4.99 MPa) when RCWTB was combined with 50% CRA. Additionally, RCWTB reduced both the embodied carbon and cost of low-strength concrete, resulting in doubled flexural-strength efficiency (flexural strength per unit of embodied carbon and cost), regardless of the CRA content. Overall, the best interaction was observed with 10% RCWTB and 50% RCA. Therefore, this study opens the possibility of simultaneously using RCWTB and CRA in low-strength concrete for applications where bending stresses predominate.