Strain response of a semi-rigid base asphalt pavement based on heavy-load full-scale accelerated pavement testing with fibre Bragg grating sensors

Full-scale accelerated pavement testing with a mobile load simulator 66 (MLS66) was conducted on a semi-rigid base asphalt pavement on a highway in Chongming Island, Shanghai, China. The goal was to investigate performance behaviour of an asphalt pavement with fine-sand subgrade in the river bed. Chongming is the terminal of G40 highway where fine sand is abundant. Although commonly found, there are little published data on its performance in a pavement structure. If found reliable in the accelerated test, the design would be used for the construction of G40 highway, which can lower the construction costs greatly and provide an engineering practice for follow-up research. Performance of the pavement structure was evaluated under high-frequency heavy trafficking while being subject to high-temperature and ambient environmental impact. This included monitoring of strains, temperature, modulus, rutting deformation, pavement depth and water level. This paper discusses the cumulative and instantaneous three-dimensional strain at the bottom of each layer in the semi-rigid base asphalt pavement. Generally good agreement was reached between the measured and calculated strains with back-calculation resilient modulus considering modulus reduction of asphalt layers because of temperature. A fatigue equation of the asphalt layer was established between loading applications, strain and seismic modulus, a small-strain value of Young's modulus. Conclusions regarding the spatial distribution, time-history change of three-dimensional dynamic strain response and the relationships between influencing factors and strains are presented.