Particle morphology effects on compaction behaviour of OGFC mixtures: Smart aggregate monitoring and DEM analysis

This study combines Smart Aggregate (SA) monitoring and Discrete Element Method (DEM) simulations to investigate how particle morphology affects the compaction behaviour of open-graded friction course (OGFC) asphalt mixtures during gyratory compaction. Specimens were prepared by varying flat-elongated particle content and abrasion level of angular aggregates. The embedded SA sensor recorded three-directional force and rotational responses, from which a Mesoscopic Stability Index (MSI*) was introduced to compare local force-rotation stability around the sensor. DEM specimens with various particle morphologies were used to analyse SA kinetic energy, velocity fields, contact composition, contact force, and local/global fabric anisotropy. Results show that increasing flat-elongated particle content reduces compactability by restricting particle motion and alignment, whereas abrasion improves compaction efficiency by weakening angular interlocking and promoting rearrangement. MSI* results suggest that moderate flat-elongated content produces a more constrained local response, while excessive content causes stronger fluctuations related to unstable local rearrangement. DEM analysis indicates that angular particles generate higher kinetic energy due to stronger interlocking, whereas elongated and flat particles influence force transmission mainly through indirect geometric constraints. The similar evolution of local and global anisotropy suggests qualitative consistency between SA response and aggregate skeleton contact-network development.