Influence of Compaction Energy on the Mechanical Performance of Hot Mix Asphalt with a Reclaimed Asphalt Pavement (RAP) and Rejuvenating Additive

Abstract

The Mexican asphalt paving industry is increasingly interested in using reclaimed asphalt pavement (RAP) to produce hot mix asphalt (HMA) due to its economic and environmental advantages. However, an ill-defined methodology for integrating RAP into the HMA mix design has hindered its use. This paper investigates how compaction energy affects both rejuvenated and non-rejuvenated recycled HMA mixtures. A Superpave gyratory compactor was used to determine the optimal binder content and find a balance between flexibility and stiffness that meets cracking and rutting resistance requirements. Various recycled HMA mixtures were subjected to different compaction energy levels (75, 100, and 125 gyros), different RAP contents (15%, 30%, and 45%), and various dosages (10%, 15%, and 36%) of the rejuvenating additive Maro-1000®, following the blending chart. Performance was evaluated using the Hamburg wheel tracking test (HWTT) and the fracture energy flexibility index test (I-FIT). The results demonstrate that mixtures with RAP, a rejuvenating admixture, and varying compaction energies exhibit favorable mechanical behavior. However, both rejuvenated and non-rejuvenated mixes with 15% RAP showed performance comparable to conventional mixtures. They improved stiffness by up to 46% while reducing the flexibility index to 25%, striking a balanced equilibrium between rutting resistance and cracking susceptibility.