INVESTIGATION OF ASPHALT CONCRETE LAYER STRAINS FROM WIDE-BASE TIRES

The application of a continuum-based finite-layer mechanistic model to evaluate pavement strain response under moving traffic loading generated from wide-base tires is presented. The model incorporates important pavement response factors such as the noncircular contact area, complex contact stress distributions (normal and shear), vehicle speed, and viscoelastic material characterization. Results of a parametric study in which two typical thin and thick pavement sections were subjected to traffic loading moving at different speeds are included. The impact of vehicle speed on the strains induced in the asphalt concrete layer is consistent with the results from several field studies. The study reveals that especially in the case of thick pavements, the fatigue failure mechanism resulting from wide-base tires is different from those generated by conventional tires. With thick pavements longitudinal fatigue cracks are expected when the wide-base tires are used

FINITE-LAYER APPROACH TO PAVEMENT RESPONSE EVALUATION

The following aspects of the proposed continuum-based finite-layer model are presented: (1) theoretical basis, (2) applicability in evaluating pavement response, and (3) verification of predictive capability. The model incorporates important pavement response factors such as noncircular contact area, complex contact stress distributions (normal and shear), vehicle speed, and viscoelastic material characterization. The proposed model is much more computationally efficient than the moving-load models based on the finite-element method. A verification study, undertaken to validate the predictive capability of the proposed approach and its ensuing computer program, is also presented. The validation study includes (1) verification using results from ELSYM5, a widely used pavement response model, and (2) laboratory verification using two foam rubber models. Very good agreement was observed in both cases. Applicability of the proposed approach has also been demonstrated using realistic pavement loading. The proposed finite-layer approach is therefore an ideal tool for modeling the behavior of asphalt concrete layer and for studying the effects of vehicle speed and complex tire-pavement interface stresses on pavement response