Performance grading and mechanistic design method of base course incorporating RCP and RCA stabilized with asphalt

With the rapid growth of construction and demolition waste (C&DW), its resource utilization has become an important research direction in road engineering. Although the application potential of recycled concrete aggregate (RCA) and recycled concrete powder (RCP) in road base courses has gained attention, the synergistic use of RCA and RCP in asphalt-stabilized base courses still lacks systematic performance evaluation methods and corresponding design theory. Furthermore, the absence of a scientific classification system tailored to different road grades results in insufficient guidance for material selection in engineering practice. To address these issues, this study first established a three-tier classification system for recycled mixtures based on performance grade (PG) through multi-scale testing and principal component analysis. Subsequently, leveraging KENLAYER mechanical simulations, a corresponding performance-graded mechanistic design (PGMD) method was proposed. Results indicate that RCP as a filler significantly enhances the high-temperature performance and deformation resistance of the mastic. The RCP75 mastic demonstrated lower temperature and frequency sensitivity, along with a broader applicable temperature range. The RCA60 mixture exhibited optimal performance in high-temperature stability and moisture stability, with improvements of 91.8 % and 6.9 % respectively, achieving a PG value of 0.878 and a Grade I rating, meeting the technical requirements for high-grade highway base courses. Based on these findings, a thickness design equation and nomogram for the base course were developed using PG and the number of axle load repetitions (N e ) as variables, balancing structural reliability and material economy. This study provides theoretical support and design methods for the standardized and high-value application of construction solid waste in high-standard road base courses. • Synergistic use of RCP filler and RCA aggregate in asphalt-stabilized base. • A performance grading (PG) system for RCP/RCA recycled base courses. • Performance Grade-based Mechanistic Design (PGMD) for RCP-RCA base. • Integrated design system from RCP-RCA materials to recycled base structure.