Validations of Anisotropic Aggregate Base Behavior from Full-Scale Pavement Tests

Low volume conventional pavement test sections with different base course thicknesses were recently constructed at the University of Illinois over a weak subgrade to evaluate pavement response and performance from accelerated loading. This paper presents the full-scale test study measured pavement responses used to validate the stress- and direction- (anisotropic) dependent unbound aggregate base behavior. Field validations involved comparing measured full-scale pavement test section responses with the predicted ones using both the isotropic and anisotropic aggregate base modulus characterizations. The nonlinear cross-anisotropic base characterization was needed to accurately predict several of the full-scale pavement section field responses and observations, such as the vertical deformation on top of subgrade, hot mix asphalt fatigue strains, and especially the large horizontal base course aggregate movements measured in the direction of traffic loading. The findings of this paper support the development of next generation of highway as well as airport pavement infrastructure by employing advanced technology and the detailed knowledge on the nonlinear, anisotropic aggregate base behavior gathered in the past 15 years of research activities.