The Influence of Aggregate Grading and Morphology on the Performance of Small-Size Stone-Matrix Asphalt Mixtures

Aggregate grading in asphalt-concrete mixtures is fundamental to the structural performance of the pavement layer they are used to build. A particle's shape, texture and angularity, representing an aggregate's morphology, also can significantly affect performance. Small-size stone-matrix asphalt (SMA) mixtures, those with aggregate of less than 9.5 millimeters, are gaining interest as thin surfacing layers for rapid maintenance, rehabilitation and pavement construction. Aggregate morphology is important in providing stability to SMA mixtures, but it is challenging to assess on particles of such small size. This study will apply a laser-based imaging system (LADAR) to characterize the aggregate morphology for comparison with conventional methods, such as uncompacted void content. The aggregates then will be used to produce small-size SMA mixtures, whose stability will be evaluated using a model-mobile loading simulator and fatigue testing plus measuring dynamic modulus and flow number.