Aggregate skeleton composition of stone mastic asphalt and its contact properties

The aggregate skeleton composition of the stone mastic asphalt with the nominal maximum aggregate size of 13.2 mm (SMA-13) and its contact properties were studied using a three-dimensional discrete element model. A user-written program was coded with the FISH language to extract the contact forces in different sized aggregates (>2.36 mm). The roles of different sized aggregates and the contact properties between these aggregates were investigated based on the statistical analysis of large amounts of data. The results of the study show that 13.2 mm, 9.5 mm and 4.75 mm aggregates form the aggregate skeleton of SMA-13 while 2.36 mm aggregates mainly fill the voids of the skeleton. Furthermore, 9.5 mm and 4.75 mm aggregates are the main body of the skeleton, which bear nearly 60% of the vehicle load.