Development of a virtual test procedure for asphalt concrete

The behavior of HMA depends on aggregate interlock achieved by aggregate-to-aggregate contact, adhesion or bondage of asphalt cement to the surface of aggregate and resistance of the network structure within asphalt cement formed by polar functional groups. In other words, performance of the mixture is dictated by the mixture properties which are the result of the properties of the individual components; binder and aggregate. At this stage, data obtained from mixture testing is not sufficient (or adequate) to ensure satisfactory performance. Hence, every attempt is made to evaluate the components of HMA. Occasionally mixes fail even though the asphalt binder and the aggregates are carefully evaluated. This may be due to poor compaction, use of incorrect binder content, poor adhesion or some other problems associated with the mixture. Measurement of the fundamental properties of asphalt mixtures is a costly and time intensive process. The availability of equipment for fundamental engineering characterization is out of the reach of majority of asphalt concrete contractors and state highway departments. There is a need for a tool for simulation of asphalt mixtures and virtual evaluation of engineering behavior based on aggregate properties and asphalt binder properties. In this research, the possibility of developing a virtual test procedure was evaluated. This procedure uses imaging and finite element analysis. Comparison of the virtual test results with the experimental values indicated that several areas need to be further investigated before asphalt cement properties can be estimated. These include the role of aggregate interaction in defining the mixture behavior, determination of in situ binder properties and effect of aggregate surface on the aging of the binders tests.