Investigation on Mechanical and Fatigue Performance of Large-Thickness Flexible Base Layer Asphalt Pavement

A static load test, single-wheel load test, and cyclic-wheel load test were carried out on large-thickness flexible base-layer and semi-rigid base-layer asphalt pavement structures by a multifunctional wheel-load testing machine. A comparative analysis was conducted on the influence and mechanism factors, such as load strength, test temperature, and load rate, on the stress and strain at the top and bottom of two asphalt pavement structures. The results show that in the interval of 1.3 MPa ≥ load intensity ≥ 0.5 MPa, with the increase of static load, the transverse strain and vertical strain at the top and bottom of the base layer of large-thickness flexible base-layer asphalt pavements increase slowly with a slight increase; the transverse strain and vertical strain at the top of the base layer of large-thickness semi-rigid base-layer asphalt pavements are more sensitive to heavy traffic load; and the transverse strain and vertical strain generated at the bottom of the base layer increase uniformly with the enhancement of static load. Under the action of a single-wheel load, the transverse and vertical strain generated at the top and bottom of the base layer of large-thickness flexible base-layer and semi-rigid base-layer asphalt pavements are alternately tensile and compressive, mainly compressive strains, while large-thickness semi-rigid base-layer asphalt pavement exhibits more complex strain changes.