The spatial design of durable asphalt mixtures relies on the size and distribution of rock particles, bitumen mortar, and void spaces. The volume of rock particles determines the grading curve of the asphalt mix. The space between rock particles influences the optimal amount of bitumen mortar and voids in the mix. The quality of bitumen mortar is affected by rock porosity, grain area, bitumen properties, and asphalt usage conditions. By understanding these relationships, engineers can create asphalt mixes that resist cracks and damage.