Application of Graphene–Basalt Fiber Asphalt Mixtures in Pavement Engineering in Seasonally Frozen Regions

Seasonally frozen regions present significant challenges in the construction, operation, and maintenance of roads. It is not possible to attain sufficient improvement in the performance of asphalt mixtures under seasonally frozen conditions using a single external additive. Therefore, dense-grained asphalt mixture AC-13 was selected as the research object in this study. Graphene and basalt fiber were applied for the composite modification of matrix asphalt mixtures (AM), and response surface methodology (RSM) was used to determine reasonable graphene and basalt fiber contents and the optimal asphalt aggregate ratio. The composite modification effect and the feasibility of its application in asphalt pavement in seasonally frozen regions were verified via road performance and freeze–thaw resistance performance tests. The evolution laws of road performance parameter indicators for graphene–basalt fiber asphalt mixtures (GBFAM) under different graphene contents, basalt fiber contents, and asphalt aggregate ratios were studied, and a significance analysis of the factors and the interactions among them was conducted. The results demonstrate the practicality of the GBFAM mixing ratio determination based on the RSM. Furthermore, compared with AM, the GBFAM exhibited superior overall performance. The optimal asphalt aggregate ratio for the GBFAM was 5.32%, with a graphene content of 0.20% and basalt fiber content of 0.30%. The GBFAM road performance parameters increased within a certain range of variation based on the optimum graphene content, basalt fiber content, and asphalt aggregate ratio, and subsequently decreased with increasing graphene content, basalt fiber content, and asphalt aggregate ratio; furthermore, the road performance parameters were approximately maximized around the optimum mixing ratio parameters. Thus, the results show that the graphene content, basalt fiber content, and asphalt aggregate ratio significantly affect the GBFAM road performance. Moreover, GBFAM exhibits excellent road performance and can be used in seasonally frozen regions for asphalt pavement engineering.