Assessing the impact of volumetric mix-design parameters and compaction levels on rutting performance of asphalt pavements: a comprehensive analysis

The research explores the impact of specific factors, such as air-void levels, mix design voids in mineral aggregates (VMA), and on-site voids, on the susceptibility of asphalt mixtures to rutting. Employing mechanistic analyses and leveraging the AASHTOWare Pavement Design program, it integrates a viscoplastic 'shift' material model with structural analysis to forecast rutting performance. The investigation primarily focuses on a 12.5 mm maximum aggregate size hot mix asphalt with PG 64–22 binder and 22% RAP content. Various mix designs are considered, including air-voids at 3%, 4%, and 5%, VMAs at 13%, 14%, and 15%, and on-site voids at 5%, 7%, and 9%. Testing protocols encompass Dynamic Modulus, triaxial repeated loading permanent deformation, and triaxial stress sweep tests. Findings consistently highlight the correlation between viscoelastic properties and rutting predictions, underscoring the significance of designed VMA levels in mechanistic analyses, and the role of air-void levels in Pavement Mechanistic-Empirical analysis.