An investigation on the use of lean asphalt as an alternative base material in asphalt pavements by means of laboratory testing, life cycle assessment, and life cycle cost analysis

Lean asphalt is a hot mixture produced with a lower binder content than a conventional dense-graded mixture. When used as a base layer, it allows for high RAP content and increases the structural capacity of the pavement compared to an unbound base. However, its low binder content and relatively high air void content raise concerns regarding its performance. This study found that about 40% RAP content is needed to meet moisture susceptibility requirements. Additionally, lean asphalt exhibited satisfactory resistance to repeated loading in fatigue testing but very low cracking tolerance in semicircular bending and IDEAL-CT testing. Furthermore, LCA revealed that pavement sections with a lean asphalt base containing 40% RAP can yield a lower environmental impact than sections with unbound or cement-bound bases with 100% recycled aggregate. Finally, LCCA substantiated that sections with lean asphalt can have a lower economic impact than asphalt pavements with other base materials.