1373851 - Simulation of Asphalt Mixture Compaction Using a Physics Engine

Computational models are increasingly being used to simulate the behavior of asphalt mixtures on account of their ability to conduct a broad range of parametric, sensitivity and probabilistic analyses. However, computational models rely on composite geometry as an input for any of these analyses. This study demonstrates the potential of using an open source “Bullet” physics engine to simulate the asphalt mixture compaction process in a gyratory compactor to obtain the input geometry. Physics engines were originally developed for animation and video games, however, with improvement in their accuracy, they are currently being used in many research areas. This model uses 3D laser-scanned representations of real aggregate particles and incorporates the viscous and cohesive nature of the asphalt mortar through customized subroutines. Results demonstrate that the compaction curves from the computational model were very similar to those recorded from the laboratory measurements. This study also evaluates the internal aggregate structure of asphalt mixtures compacted using the model and compares with the laboratory compacted specimens. Results indicate that the aggregates preferred to align themselves both in laboratory compaction and virtual compaction. However, the magnitude of preferential orientation was observed to be higher in laboratory compaction as compared to the virtual compaction. Two different set of aggregate shapes were used in virtual compaction to compact the asphalt mixture. Changing the aggregate shape to reduce its sphericity increased the magnitude of orientation of the virtually compacted sample and was comparable to the laboratory compacted sample.