Study on the Performance and Adhesion Behavior of Ultrathin Wearing Course Using Calcined Bauxite as Aggregate

An ultrathin wearing course is an effective maintenance treatment for prolonging the service life of asphalt pavements, which have been widely used in the field of pavement construction and road maintenance. However, the repeated vehicle load and wear results in a decreased durability of ultrathin wear course cover pavement. Hence, the gradation of ultrathin wear course was designed using calcined bauxite in this study, and the water stability, low-temperature properties, resistance to permanent deformation, and salt erosion were investigated through a laboratory test. Results indicated that the addition of a nonammonia antistripping agent significantly improves the water stability of the asphalt mixture with calcined bauxite and its ability to resist salt erosion as well as improve its low-temperature deformation ability. At the same time, polyphosphoric acid improves the adhesion between asphalt and calcined bauxite aggregate and the high-temperature performance of asphalt mixture but has limited improvement in water stability and resistance to salt erosion. This research is conducive to the widespread use of calcined bauxite aggregates in road pavements and is of great significance for improving the durability of ultrathin wear course asphalt pavements.