Unveiling the influence of aggregate particle morphology on structural uncertainty in asphalt concrete via digital composite modeling

Structural variability in aggregate assemblies is a major source of uncertainty that undermines the reliability of concrete and asphaltic composites, leading to discrepancies between design predictions and in-service performance. This study develops a digital modeling framework to attribute and quantify the origins of such structural uncertainty. A total of 42 coarse aggregate morphological descriptors and 47 structural indicators were introduced to construct attribution analysis models. Statistical significance testing was employed to rank aggregate shape and size parameters into nine levels, followed by cumulative distribution analysis to assess their contribution to variability in packing structure. The results reveal that aggregate characteristics related to dominant DASR particles (4.75–9.5 mm), particle size distribution, and mean statistical measures (μ) play decisive roles in inducing structural uncertainty. Furthermore, skeleton-forming particles and their interfering fractions—particularly in the 2.36–4.75 mm and 4.75–9.5 mm size ranges—exert significant influence through size distribution and angularity. Based on these findings, a quantitative framework is proposed to control meso-structural variability in granular composites by linking aggregate morphological statistics to internal packing behavior. This framework provides insights into improving mixture design strategies and enhancing the structural reliability of concrete and asphalt materials.