RIOHTrack Full-scale Accelerated Loading Tests and Long-term Performance Observation Studies

To address the limitation that field sections cannot verify the full-life-cycle performance of long-life asphalt pavements (structural service life ≥50 years, surface functional life ≥15 years), this study conducted long-term accelerated loading tests and performance observations on Research Institute of Highway Ministry of Transport full-scale test track (RIOHTrack) Full-Scale Test Track. RIOHTrack includes 19 asphalt pavement sections (classified into seven types by asphalt concrete [AC] layer thickness and base type). By June 2025, cumulative equivalent single axle loads (ESALs) reached 130 million, equivalent to 38 years of extremely heavy traffic on Chinese expressways. Key indicators (deflection, rutting, cracking, texture depth, roughness) were monitored using falling weight deflectometer (FWD), laser scanning, and three-dimensional ground-penetrating radar (3D GPR), and so on. Results showed: 1) Load–environment coupling induced annual periodic fluctuations in deflection, rutting, and texture depth, with temperature impacts exceeding load effects. 2) Deflection exhibited nonlinearity: negative thixotropy (deflection decreased with AC thickness) and load dependency (fitted power function, R ² >0.99). 3) Rutting followed an inverse “S”-shaped evolution, originating from the 4 cm surface AC layer for sections with AC thickness ≤36cm. 4) Surface cracks were predominantly top-down (T-D) with a negative correlation to rutting; no alligator cracking occurred, and internal cracks increased with load. 5) Rigid bases and high-modulus AC significantly improved bearing capacity and rutting resistance. Most sections met requirements of long-life pavement, with “thin AC layer + high-strength semi-rigid base” (STR1) being optimal (cost-effective, low carbon). Asphalt pavements undergo bidirectional fatigue damage (T-D surface fatigue and bottom-up structural fatigue), supporting dual-life design. This study provides empirical data for developing durable, low-carbon technologies for long-life asphalt pavement.