Comparative study on mechanical properties of asphalt pavement with flexible base and semi-rigid base based on cyclic wheel load experiment
Abstract
To clarify the differences and mechanisms of response between flexible and semi-rigid base asphalt pavements under cyclic loading, a systematic comparative study was conducted through cyclic loading tests, with surface displacement and base top/bottom strain as the core indicators. The results show that the displacement of the two types of pavement surface layers and the strain of the base layer both exhibit a three-stage cumulative evolution of “initial stability-slow growth-accelerated failure” with the load, and the response is synchronized with the load action. The displacement of the flexible-base pavement surface layer (2.5-8 mm) and the amplitude of the base strain are larger, and the base layer remains continuously under tension. The displacement of the semi-rigid-base pavement surface layer (2-6.5 mm) is concentrated, the elastic rebound is obvious, and the strain amplitude of the base layer is small; moreover, the brittleness increases suddenly in the later stage. The root cause of the difference lies in the modulus and deformation characteristics of the base material: the high modulus of the semi-rigid base layer is subjected to force as a rigid plate, while the low-modulus viscoelasticity of the flexible base layer forms a synergistic deformation of the composite beam. The research results provide a theoretical basis for the selection of asphalt pavement structure, anti-fatigue design, and optimization of service performance.