Coupling effects of temperature and vehicular speed on mechanical responses of thin asphalt pavement overlay using viscoelastic finite element model

Purpose Thin overlay technology is widely used to restore pavement performance and extend service life, but its thin layer makes the interfacial bonding with underlying pavement susceptible to traffic load damage. This study aims to investigate the mechanical responses of thin overlays under various loading and environmental conditions, which is crucial for guiding the rational application of thin overlay technology. Design/methodology/approach Dynamic modulus tests were first carried out to determine and compare the viscoelastic properties of thin overlay mixtures and original asphalt layers. The obtained viscoelastic parameters were then incorporated into a viscoelastic finite element model that considers tire-pavement interaction, to systematically analyze the mechanical responses of pavements with and without thin overlays under different service conditions. Findings Thin overlay mixtures have lower dynamic modulus and higher phase angle than original pavement mixtures, indicating higher viscosity and better deformation capacity. Interfacial shear stress between the overlay and original asphalt is significantly influenced by temperature and vehicle speed, reaching its maximum at intermediate speeds and high temperatures. Compared with conventional asphalt pavements, thin overlays effectively reduce shear stress, tensile stress and vertical strain within the pavement. Originality/value These findings clarify the mechanical behavior of thin overlays under complex service conditions, providing valuable insights for the design of asphalt pavements with thin overlays and helping to enhance the overall structural capacity and service performance of pavements.