The heat flux evolution of porous asphalt mixture based on meso-structure and its influence on heat transfer property

The aim of this study was to investigate the impact of internal structure evolution on the heat transfer characteristics of porous asphalt mixtures using finite element software. Image processing software was used to image Marshall specimen sections and to establish a finite element model that accurately represents the actual distribution of pavement material. The analysis centered on changes in internal heat flux, which relates to the manner in which changes in the mixture's internal structure affect its heat transfer performance. A porous asphalt mixture with 5 mm and 10 mm longitudinal strain was obtained which exhibited lower surface temperatures 1.331 degrees C and 2.406 degrees C higher, respectively, compared to mixtures without longitudinal strain Conversely, after 120 min of heat dissipation under the same conditions, the mixtures with longitudinal strains of 5 mm and 10 mm showed lower surface temperatures 1.232 degrees C and 1.628 degrees C lower, respectively, compared to mixtures without longitudinal strain. As the longitudinal strain of the porous asphalt mixture increased, the heat flux distribution inside the mixture tended to become more uniform. At the onset of heating and cooling, porous asphalt mixtures without longitudinal strain exhibited a faster rate of temperature change at the upper surface compared to mixtures with longitudinal strain. Additionally, longitudinal strain in porous asphalt mixtures reduced their thermal resistance properties, allowing for more efficient heat transfer to the interior of the mixture under identical heating conditions.