Optimizing Aggregate Packing Degree for Enhancing Rutting Resistance in Asphalt Mixtures

Abstract: Resistance to rutting is among the most critical parameters in achieving durable asphalt pavements, particularly for high traffic and high-temperature conditions. Effective rutting performance is obtained through proper aggregate gradation, which packing theory quantified by optimizing how aggregates fit together. While the Superpave mix design did incorporate some considerations about packing, further refinement is needed to optimize the gradation of the asphalt mixture concerning rutting resistance. Current asphalt mixture designs do not fully leverage packing optimization for rutting resistance, potentially leading to premature pavement deformation under challenging conditions. There is limited clarity on which packing calculation methods most effectively enhance this resistance. This study aims to present the calculations of the packing methods that best improve rutting resistance, evaluating different calculation approaches. Examining various approaches with consistent aggregate gradation aims to establish a framework that links packing optimization with improved rutting performance. The study utilizes the Hamburg Wheel Track Test, with rutting resistance measured by the Hamburg Performance Index, to assess the performance of asphalt mixtures with different packing methods. These include the Bailey method, the Toufar method, the compressible packing model, the Furnas method, the Shilstone method, the modified Fuller-Thompson method, and several other models applied to consistent gradation. The study anticipates identifying an optimal set of packing methods that correlate with improved resistance to rutting. This framework will serve as a guide for gradation selection, enhancing asphalt mixture durability in demanding environments.