Static versus viscoelastic wave propagation approach for simulating loading effects on flexible pavement structure

•FE model is proposed to simulate viscoelastic wave propagation of pavement responses.•Dynamic effect contributes mostly to deflection time delay and response oscillations.•Material viscoelasticity significantly contributes to response magnitude and pattern.•Viscoelastic wave propagation approach more closely simulates field measurements.

Conventional pavement design methods use static and elastic approaches for stress and strain analysis. The hot mix asphalt (HMA) layer is a typical viscoelastic/viscoplastic material as temperature and time dependent, and the more recently developed mechanistic-empirical pavement design guide (MEPDG) has adopted HMA’s dynamic moduli as parameter inputs. However, its stress and strain modeling is based on a static analysis for emulating the dynamic vehicle loading. This study aims to evaluate the effects of static versus viscoelastic wave propagation simulation approaches on pavement responses using finite element method. Four simulation approaches are proposed: (1) static elastic, (2) elastic wave propagation, (3) static viscoelastic, and (4) viscoelastic wave propagation approaches. Two pavement structures under the falling weight deflectometer and vehicle loadings are modeled. Frequency spectrum, modal shape, deflection, stress, and strain are analyzed. Results indicate that the dynamic effect significantly contributes to the time delay of deflections to loading and response oscillations at the rest time due to wave propagation. Material viscoelastic property significantly contributes to the response magnitude and pattern, resulting in higher deflection on the pavement top, higher tensile strain while lower tensile stress at the HMA bottom as compared to quasi-elastic analysis. The viscoelastic wave propagation simulation approach yields closer results with measurements, and thus is recommended for the future pavement analysis and design.