In order to improve the properties of calcium sulfate anhydrous whisker (ACSW) and polyester fiber composite reinforced asphalt mixture (ACPRA) to meet the service requirements of pavement materials in low-temperature environments, the central composite circumscribed design (CCC), a kind of response surface methodology, was chosen to optimize the design parameters. Three independence variables, asphalt aggregate ratio, ACSW content, and polyester fiber content were adopted to evaluate the design parameters. Four responsive variables, air voids, Marshall stability, splitting tensile strength, and failure tensile strain, were chosen to study the volumetric and mechanical characteristics, and the low-temperature behavior of ACPRA by the Marshall test and indirect tensile test at −10 °C. The results showed that, taking low-temperature behavior optimization as the objective, the CCC method was practicable to optimize design of ACPRA, and the optimization design parameters were asphalt aggregate ratio of 4.0%, ACSW content of 10.8%, and polyester fiber content of 0.4%. Furthermore, the impact of three independence variables interactions on four response variables was also discussed, and it was identified that the interaction between asphalt aggregate ratio and ACSW content, and between asphalt aggregate ratio and polyester fiber content, has greater bearing on the splitting tensile strength and failure tensile strain of APCRA. Meanwhile, ACSW and polyester fiber enhancing the low-temperature behavior of APCRA was primarily connected with their contents.

Coal gangue, a solid waste from coal mining, has long been underutilized while posing environmental and safety risks. This study reviews the current research progress and future prospects of coal gangue as a resource in asphalt pavement. The physical and chemical properties of coal gangue were summarized, and the environmental issues caused by its accumulation were highlighted. The effects of using coal gangue as aggregates or fillers in asphalt mixture were reviewed, along with its activation methods. The research progress on using coal gangue as an aggregate or a cementitious material in mixtures stabilized with inorganic binders was also examined, emphasizing the effects of binder content and coal gangue properties on mechanical and durability performance. The findings indicate that despite its inferior physical properties, coal gangue demonstrates practical feasibility as a pavement material when appropriately incorporated and activated. Proper content enabled coal gangue to meet asphalt mixture or base material requirements, while excessive content reduced low-temperature resistance and caused structural defects. Activated or modified methods can effectively enhance interfacial interaction, high-temperature stability, or structural densification of coal gangue. Recent studies have expressed enthusiasm for innovative activation or modification methods and AI-based performance optimization, while key challenges remain regarding high activation-energy demand, limited aggregate-related research, and an incomplete understanding of interfacial mechanisms.