To enhance the accuracy and reliability of the discrete element simulation software EDEM 2023 for pavement asphalt mixture simulation, three representative coarse aggregate particles were modeled in 3D using the SolidWorks 2018 software and imported into the EDEM 2023 software for particle filling. The Hertz–Mindlin with bonding contact model was used to construct the EDEM simulation model of asphalt mixtures, and the quadratic regression model of asphalt mixtures’ splitting tensile strength and four bonding parameters, namely, normal stiffness per unit area, shear stiffness per unit area, critical normal stress, and critical shear stress, was found by the response surface methodology. The results show that the relationship between the significance magnitude of the four bonding parameters on the splitting tensile strength of the asphalt mixture simulation model is as follows: critical normal stress > shear stiffness per unit area > normal stiffness per unit area > critical shear stress. The calibration results of the bonding parameters were used for simulation verification, and the relative error between the simulation and actual splitting tensile strength was only −2.48%. The feasibility of this bonding parameter calibration method is demonstrated, and it can lay a foundation for EDEM to simulate the performance of asphalt mixtures on pavements with high-precision simulation.

This study aimed to address the issue of inadequate water resistance in asphalt pavement tack coat materials by preparing super adhesive emulsified asphalt (SAE). Due to the lack of consideration of dynamic water scouring in previous studies on the water resistance analysis of tack coat materials, this research employed self-designed inclined shear, pullout, and dynamic water scouring devices to examine the shear and tensile strength of matrix emulsified asphalt, styrene block copolymer (SBS)-modified emulsified asphalt, and SAE under various conditions of sprinkling volumes, temperatures, and scouring times. The findings indicate that, in the dynamic water scouring test conducted under the optimal sprinkling amount of tack coat material and the most unfavorable temperature conditions between layers, SAE exhibited residual shear and tensile strengths that were higher than SBS-modified emulsified asphalt and matrix emulsified asphalt. Combining polymerized styrene butadiene rubber (SBR) and polyurethane (PU) as two modifiers in the mix exhibits a synergistic effect, enhancing the bonding performance, scouring resistance, and water resistance of SAE as the tack coat material.

Carbon fiber powder (CFP) was first applied to conductive asphalt concrete as a conductive phase material, but its action mechanism has not been clarified. In this paper, atomic force microscopy (AFM) and molecular dynamics (MDs) simulation are used to study the carbon fiber powder mechanism of action, guide the preparation of conductive asphalt concrete, and study the electrothermal properties of conductive asphalt concrete. The results show that carbon fiber powder weakens the adhesion property of asphalt mastic, and this weakening further strengthens in the water–temperature coupling, so water stability and conductivity are used as evaluation indicators to determine that the optimal content of carbon fiber powder is 2.0% and that the optimal content of carbon fibers (CFs) is 0.4%. Carbon fiber–carbon fiber powder conductive asphalt concrete with a resistivity of 0.98 $\mathsf{\Omega }·\mathrm{m}$ was finally prepared. In the temperature rise test of the Marshall specimen and rutting slab, its warming effect is obvious, and the heat transformation rate is more than 75%, so it has a very good ability to melt snow and ice.

The service years of the milled pavement are varied in numerous SBS modified asphalt pavement milling assignments. To investigate the milling characteristics of SBS (styrene–butadiene–styrene) modified asphalt pavements with different service years, the values of the bonding parameters were calibrated and verified and then used to build three simulation models for the milling of old asphalt pavements with service years of 2~3 years, 7~8 years, and 11~12 years, respectively. The milling characteristics of SBS modified asphalt pavements with different service years were investigated using the moving speed $v$ and rotating speed $\omega$ of the milling rotor as test factors, and the particle bonding ratio ($R_b$) and rotor average force ($F_a$) as test indexes. The results demonstrate that the following: The regularity of the effects of milling rotor moving speed and rotating speed on the particle bonding ratio and milling rotor average forces remained consistent overall as the pavement age increased. For the same milling parameters, the particle bonding ratio and the rotor average force are reduced. From 2~3 years old pavements to 7~8 years old pavements, the overall reduction in the particle bonding ratio indicator is about 12%, and the average force on the milling rotor is about 24%. From 7~8 years old pavements to 11~12 years old pavements, the overall reduction in the particle bonding ratio indicator is about 3%, and the average force on the milling rotor is about 15%.