Estimating Truck Aggressiveness Using a Multilinear Fatigue Model and a Viscoelastic Pavement Model

Abstract

To increase freight efficiency, trucks are allowed to transport heavier loads without adding extra axles. The impact of this practice on infrastructure damage needs to be evaluated. This involves evaluating the fatigue life of asphalt pavements under multiple axle configurations. In mechanistic pavement design, the asphalt thickness is generally determined using a fatigue model calibrated in the laboratory by applying a continuous sinusoidal signal with different strain levels. The classical fatigue relationship gives fatigue life as a function of the strain level. However, results from literature show the influence of the loading wave shape on the fatigue life of bituminous mixtures. Real loading signals under multiple axle configurations are more complex in shape than sinusoidal pulses. Moreover, real strain signals have different shapes in the longitudinal and transverse directions. This paper presents an approach using a multilinear fatigue model that takes into account the shape of the loading signal coupled with a viscoelastic pavement model. Using this approach, a parametric study is made to evaluate the effect of loading variables on fatigue life, as well as comparisons between the aggressiveness of different truck configurations including European Modular Systems (EMS).