## 1 Introduction  
A phenomenon in which temperatures in rural areas are lower than in cities has been referred to the urban heat island (UHI) effect [1]. UHI has a direct impact on urban livability, including a decrease in environmental quality, an increase in thermal discomfort, and an increase in heat-related health issues [2]. Satellite images demonstrate that pavements are a substantial source of thermal activity and heat radiation, particularly in urban areas [1]. Ninety percent of solar energy is absorbed by asphalt pavement, as well as warmth that builds within the pavement, increasing its temperature. Studies have shown that hot pavement has a significant impact on the near-surface heat island. The UHI impact is exacerbated as heat from the pavement is released into the atmosphere via convection and effective radiation [3, 4]. Thermal conductivity is a critical material of parameters that determine the temperature field of the pavement, and it is essential for evaluating numerous pavement methods for UHI mitigation [5]. Asphalt concrete is a viscoelastic material, and under normal circumstances, the smaller the thermal conductivity, the slower the heat conduction [6]. Pavement mechanical qualities and temperature distribution are substantially affected by the thermal conductivity of asphalt concrete, which also has a knock-on impact on pavement service life and the urban heat island effect [7, 8]. Understanding the thermal conductivity of asphalt concrete is critical for estimating the thermodynamic performance of pavement, studying the efficiency of the heat transfer from road surface to subgrade, alleviating the UHI effect, and promoting the sustainable development of pavement. Experimentation is now the most used approach for determining the thermal conductivity of asphalt concrete. The slab technique, the guarded heat-flow meter method, the transient plane heat source method, and the hot-wire method are all common methods to measure thermal conductivity in thermal conductivity studies [9; 10; 11]. [PERSON] et al. investigated the effects of expanding polypropylene beads and adding graphite powder on the thermal conductivity of HMA [12]. [PERSON] et al. examined the thermal conductivity of permeable concrete by replacing it with recycled coarse aggregate and recycled asphalt pavement for natural aggregate [13]. [PERSON] et al. studied the thermal conductivity of conductive asphalt concrete using seven different aggregates and two conductive fillers [14]. [PERSON] et al. analyzed various aggregates, combinations, and air voids for their impact on thermal conductivity [15]. Although these experimental methods are commonly used and simple to operate, there are still some limitations in the experiment. Expensive measuring devices and a huge number of specimens are required in the experiment, which consume a large amount of measurement time and economic costs. As a heterogeneous composite material, thermal conductivity, volumetric fractions, and distributions of each component in asphalt concrete all affect the overall effective thermal conductivity of the material. Costs associated with experiments may be considerably reduced by developing an analytical model to forecast effective thermal conductivity based on the heterogeneous meso-structure of asphalt concrete. According to the thermal conductivity and volumetric fractions of every component, analysis models for composite material thermal conductivity have been developed by researchers, such as the parallel model, series model, Maxwell-Eucken model, effective medium theory model, and Bruggeman's equation [16; 17; 18; 19; 20]. However, as these models are usually based on specific aggregate distribution forms where the distribution patterns of the two components in asphalt concrete are simple and different from the heterogeneous meso-structure of real asphalt concrete, and the thermal conductivity that is predicted is not the real situation.