Characterization, experimental validation and life cycle assessment of wind energy industrial waste in asphalt...

The expansion of wind energy has increased the generation of welding slag, an industrial by-product that is still mainly landfilled due to limited valorization options. This situation represents both an environmental burden and a loss of potentially reusable material. The present study assesses the feasibility of utilizing this material as a secondary raw material in asphalt mixtures through full replacement of the mineral filler (3 wt%). The characterization of welding slag from wind turbine tower manufacturing involved the utilization of multiple analytic techniques including XRF, XRD, ICP-MS, SEM-EDS, followed by mechanical processing prior to its incorporation into a dense-graded asphalt mixture (AC16 Surf). The performance of the system was evaluated in a laboratory setting and subsequently validated in a full-scale road section under real-world service conditions. A cradle-to-gate Life Cycle Assessment was conducted for the purpose of quantifying the environmental impacts. The material exhibited a stable inorganic composition, characterized by minimal levels of trace elements. The modified mixtures are characterized by technical specifications, that exhibit analogous volumetric and mechanical behavior to the reference mixture, with Marshall stability value of approximately 12 kN and flow values approximating 3 mm. Following a period of five months in service, the pavement demonstrated adequate compaction (void contents 4.1-4.3%), moisture resistance (ITSR = 91.5%) and skid performance (PTV = 79). The environmental analysis indicated a reduction in global warming potential exceeding 10% (from 95.2 to 85.9 kg CO₂eq per ton of mixture), mainly associated with avoided landfill disposal and reduced use of natural filler.