Developing Low-Carbon Concrete from Recycled Wind Turbine Blades: Fresh and Short-Term Properties

Abstract

This study investigates the fresh and short-term properties of supplementary cementitious materials (SCMs) derived from retired wind turbine blades, specifically glass fiber–reinforced polymer (GFRP) and GFRP after thermal degradation treatment (GF550), with fly ash (FA) serving as a reference material. The research focuses on three primary areas: raw material characterization, fresh properties testing, and mechanical property testing, accompanied by relevant characterization analysis. The results demonstrate that GF550, produced via thermal degradation treatment of GFRP, exhibits superior characteristics as an SCM, with smoother surfaces; higher concentrations of silicon, aluminum, and calcium; and a finer particle size distribution. These properties contribute to better workability and enhanced hydration processes compared to GFRP. In contrast, GFRP displayed reduced workability and significantly retarded hydration, particularly at higher replacement ratios, despite the addition of superplasticizers. The mechanical property tests revealed that GF550, at a 10% replacement ratio, achieved compressive strengths comparable to FA, with strength activity indices (SAIs) close to 87%. However, the use of GF550 at higher replacement ratios, especially 50%, resulted in significant reductions in compressive strength, largely attributed to increased porosity and lower hydration product formation. This study provides critical insights into the potential of using recycled wind turbine blade materials as SCMs in cementitious applications, highlighting both the opportunities and challenges associated with their use.