Life Cycle Assessment of hot mix asphalt with increasing reclaimed asphalt pavement using Beam-Down linear Fresnel solar heating

This study assesses the environmental performance of hot mix asphalt (HMA) with increasing reclaimed asphalt pavement (RAP) contents, considering a solar-assisted RAP preheating system based on a beam down linear Fresnel reflector (BDLFR) field. A life cycle inventory is developed from mass and energy balances of a batch HMA plant operating at 100 t/h under two configurations: (i) a conventional process with cold RAP addition (10–50% by mass) and (ii) a solar-assisted process where RAP is preheated to 90 °C using a BDLFR-fed conveyor belt receiver. A life cycle assessment is performed with a functional unit of 1 t of HMA, applying the Environmental Footprint 3.1 method and focusing on climate change, particulate matter, ozone depletion, and land use. A conventional asphalt mixture without RAP is used as the benchmark. Results show that higher RAP contents reduce environmental impacts in both configurations, with additional benefits from solar preheating. The solar-assisted scenario with 50% RAP achieves reductions of approximately 79.5% in climate change, 76% in particulate matter, 88.6% in ozone depletion, and 81.9% in land use compared with the benchmark, and avoids about 10 kg CO 2 eq per ton of HMA relative to the non-solar 50% RAP case. Although the BDLFR field introduces additional land use, this contribution remains lower than that associated with virgin aggregates. Virgin aggregates, bitumen, and fuel oil consumption dominate environmental impacts. The results indicate that combining high RAP contents with solar preheating is an effective strategy to significantly reduce the environmental footprint of HMA production.