The feasibility of DEM to analyze the temperature field of asphalt mixture

• Digital sample was reconstructed considering discontinuity of asphalt mixture meso-structures.
• A discrete element model was established considering the contact thermal resistance.
• Numerical simulation results from DEM model were validated with experimental results.
• A better heating scheme was proposed to improve bulk temperature of asphalt mixture.

To discuss the feasibility of the discrete element method (DEM) to analyze the temperature field of asphalt mixture materials, the digital specimen of rutting plate was reconstructed based on the mix design of asphalt mixture. Also, considering the contact thermal resistance, a discrete element thermal analysis model was established based on the discrete element heat conduction equation and its discretization. The temperature field distribution in digital specimen was discussed using the DEM model, and which was compared with the experimental results on the actual rutting plate. The results indicated that the discontinuity of mesoscopic structures in asphalt mixture was fully considered in digital specimen based on the digital image processing. The internal structures of asphalt mixture specimen were reappeared, and the transient heat conduction discrete element model was established after the heat flux was applied on the specimen surface. Further, thermal responses of the upper part were faster than that of the lower part in discrete element model during continuous heating. The bulk temperature in digital specimen continued to rise after the heating was over. Similarly, the measured temperatures of upper part were higher than that that of lower part in rutting plate under both continuous and intermittent heating schemes. However, the surface temperature was lower under the intermittent heating method, reducing the asphalt aging and improving the bulk temperature and its uniformity of the specimen. It is concluded that numerical simulation results using DEM are basically consistent to experimental results. The DEM may become a new promising approach to study the temperature field distribution and other properties of asphalt mixture materials.