Microscopic Characteristics of Field Compaction of Asphalt Mixture Using Discrete Element Method

To investigate microscopic characteristics of the field compaction of asphalt pavement, a three-dimensional (3D) compaction model of asphalt pavement considering morphological characteristics of aggregate and temperature effect was established by distributed load and time equivalence principles using Particle Flow Code in Three Dimensions (PFC3D). The microscopic parameters of hot asphalt mixture were determined with a dynamic modulus test based on the time-temperature superposition principle. Aggregate motion, contact force, and the evolutional mechanism of energy were monitored during the virtual compaction process. This indicated that the motion displacement, angle, and stress are positively associated with load direction. It is necessary to select the proper plane angle with the load direction to evaluate the 3D motion of the aggregate with the two-dimensional (2D) plane angle. During the compaction process, the contact compressive force is mainly produced between aggregates, and the evolution laws of contact force and stress tensor can be used to reasonably interpret the aggregate motion within the asphalt mixture. Additionally, the work of external force, kinetic energy, and strain energy can be employed to precisely demonstrate energy conversion for the developed compaction model. Indexes including motion displacement and angle, contact force, and energy can reflect the microscopic characteristics of asphalt mixture during field compaction. It is rational and feasible to analyze microscopic behavior of asphalt pavement with the proposed pavement compaction model using the discrete element method (DEM). The DEM is a significant tool of investigation of microscopic characteristics of asphalt pavement.