To accurately quantify asphalt–aggregate adhesion and evaluate mixture stability and workability during construction, a cost-effective testing apparatus was developed to simulate and measure mass loss in asphalt mixtures throughout plant production processes. Through a combination of the developed adhesion test and Particle Flow Code in 3 Dimensions discrete element simulation, four key parameters, sample mass, rotation cycles, rotation rate, and test temperature, were identified and optimized. The meso-scale movement patterns and mechanical behavior of mixture particles during mixing were also analyzed. To expand applicability, both dense-graded mixtures (AC-25 and AC-20) and a gap-graded mixture (SMA-13) were tested to investigate the effects of asphalt–aggregate ratio, gradation, and aging time on asphalt–aggregate adhesion behavior. The final test protocol was established as follows: 2.5 ± 0.05 kg sample mass, 250 rotation cycles, 10 rpm rotation rate, and 170°C ± 0.5°C test temperature. These conditions effectively simulate particle convection and migration during mixing, ensuring stable accumulation of adhered mass on the filter paper. The mass loss rate (Δm) was used as the quantizing indicator of asphalt–aggregate adhesion. The Δm versus asphalt–aggregate ratio curve exhibited three distinct phases: dry scattering, saturation, and oil bleeding, with the saturation phase defining the optimum asphalt–aggregate ratio range. Based on this method, optimal asphalt film thickness and filler–asphalt ratio thresholds were proposed for different mixture types. Additionally, the allowable waiting time before paving should not exceed 2 h to ensure proper adhesion and workability.