Porous asphalt mixtures play a pivotal role in enhancing pavement drainage capacity and traffic safety, where the performance of asphalt binder constitutes a determining factor. This study introduces an innovative advancement through the development of a high-viscoelastic modifier and corresponding modified asphalt based on SBS-modified asphalt, coupled with optimized preparation protocols. The optimal composition and dosage of the modifier were systematically determined through standardized tests including penetration, ductility, softening point, and bending beam rheometer (BBR) analysis. A comprehensive evaluation of road performance was conducted on two porous asphalt mixtures, namely conventional SBS-modified asphalt versus the novel high-viscoelastic modified asphalt (designated as 10-A). Experimental protocols encompassed high-temperature rutting resistance tests, low-temperature beam bending tests, freeze–thaw splitting tests, two-point bending fatigue tests, accelerated abrasion tests, and dynamic friction tester (DFT) measurements. The results demonstrate that the 10-A-modified mixture exhibits superior high- and low-temperature performance. Notably, its fatigue resistance and skid resistance showed minimal divergence from conventional SBS-modified asphalt, attributable to physicochemical crosslinking interactions among antioxidants, resins, and stabilizers. This research elucidates the synergistic mechanism of components within the 10-A modifier system. The proposed high-viscoelastic asphalt formulation meets the technical requirements for functional drainage asphalt mixtures while providing material-level support for implementing sponge city initiatives.

Polyurethane (PU) materials, with their excellent mechanical properties, durability, and fatigue resistance, hold promise for addressing the challenges of aging, environmental pollution, and segregation during the storage of modified asphalt mixtures, thereby extending the lifespan of pavements and enhancing the level of service. Although studies have been conducted on the road performance of PU mixtures that compared them with asphalt mixtures, there is relatively less research on how the air void of PU mixtures affects their performance. This study systematically investigates the dynamic characteristics and road performance of dense-graded PU mixtures at three air void ranges—1%–3%, 3%–5%, and 5%–7%—and verifies the effectiveness through statistical methods. The research results show that air voids have a significant impact on road performance. Compared to low air voids, high air voids can increase high-temperature performance by 12%–33%. However, higher air voids also lead to a significant decrease in resistance to water damage, with a reduction of about 9%–24%. When the air void is in the range of 3%–5%, the mixture has better dynamic stability. Therefore, when designing PU mixtures, a reasonable air void should be selected based on engineering conditions to achieve the optimal pavement structure combination and save investment. This study provides a scientific basis for the design and application of PU mixtures and lays the foundation for further understanding of their performance mechanisms.