Effect of Gradation on Volumetric and Mechanical Properties of Asphalt Mixtures Using Bailey Method

Abstract: The gradation of aggregates plays a crucial role in determining the performance of asphalt mixtures. This study investigates the impact of aggregate gradations on both the volumetric and mechanical properties of asphalt mixtures. The Bailey method is applied to design and analyze gradations, with a specific focus on evaluating voids in mineral aggregates (VMA) as a key volumetric property. Mechanical performance of asphalt mix is assessed through rutting resistance using the Hamburg wheel tracking test (HWTT) and cracking resistance using the Indirect tensile asphalt cracking test (Ideal-CT). Additionally, Bailey parameters such as coarse aggregate ratio, fine aggregate coarse ratio, and fine aggregate fine ratio are calculated. The research explores the correlations between Bailey parameters and the observed volumetric and mechanical properties of the asphalt mixtures. Moreover, it examines the influence of the coarse and fine fractions of the gradation on the mechanical performance of the asphalt mix. The findings of this study enhance the understanding of gradation optimization and provide recommendations for improving the performance of asphalt mixtures by adjusting gradation parameters to meet specific volumetric and mechanical performance criteria. This study also helps asphalt mix designers to gain a deeper understanding of the relationship between volumetric properties and asphalt mix mechanical properties, offering insights to improve mixture design.