Evaluation of Effects of Variations in Aggregate Base Layer Properties on Flexible Pavement Performance

Abstract

This paper aims to evaluate flexible pavement responses and performance affected by variations in the aggregate base layer properties. An advanced three-dimensional finite element (FE) model was developed to capture the nonlinear cross-anisotropic behavior of granular material. The FE model characterized the hot-mix asphalt layer as a viscoelastic material and used moving load to predict time- and temperature-dependent pavement responses under different temperatures (25°C and 45°C). Two asphalt pavement sections with different asphalt layer thicknesses (3 and 5 in.) were analyzed, considering variations in aggregate properties. The response changes in the asphalt layer, aggregate base layer, and subgrade depended on the interaction between viscoelastic asphalt layer and stress-dependent aggregate base layer. Fatigue cracking and subgrade rutting were more affected by changes of aggregate base layer properties among different failure mechanisms in each pavement layer. The coefficient of curvature and complex maximum dry density served as the contributing parameters most affecting fatigue cracking potential, especially for the relatively thinner asphalt pavement at the higher temperature. However, the moisture content ratio affected the subgrade rutting potential more than other parameters did. These conclusions serve as the basis for selecting optimum aggregate properties for pavement design and developing a performance-related specification for quality control and quality assurance in pavement construction.