The rise in renewable energy usage has led to an increased focus on the recycling of wind turbine blades at the end of service life, due to a significant waste concern associated to their significant quantities. These blades, primarily composed of Glass Fiber Reinforced Polymer (GFRP), present a recycling challenge, as their material composition and potential secondary life applications are not widely established. This study aims to assess the efficacy of using recycled fibres from these blades into cementitious mortars, while also evaluating the environmental performance of giving these turbine blades a second life. A novel procedure is proposed for the segmentation and grinding of the blades into fibrous mixtures with known dimensional distributions. Various mixes for the mortars were prepared and tested, incorporating different percentages of recycled fibres. Alongside this, a sustainability assessment was conducted, analysing several recycling scenarios to evaluate their environmental impact. The findings indicate that the effectiveness of recycled fibres in enhancing the properties of mortars is promising only in certain compositions and production scenarios. The results suggest that the environmental benefits of recycling wind turbine blades into construction materials are contingent on specific factors, such as transportation scenarios and energy supply for processing recycled fibers.