Novel Approach for Characterization of Unbound Materials

Abstract

The current inclination toward establishing a mechanistic pavement analysis scheme to support rehabilitation design will require adopting mechanical materials properties. Mechanistic properties are needed for establishing the material-mechanics link, which represents the most effective approach for accurately predicting the response of road structures and their performance. Physical characteristics served early design practices with a common understanding among users that a more robust approach is needed to address rehabilitation design requirements effectively. Current attempts to improve material characterization based on the outcome of mechanical tests focusing on unbound materials are discussed. It is concluded that simplifying assumptions built in the proposed testing schemes and the manner in which these properties are determined overlooked other critical behavior indicators. Results of field and laboratory investigations highlight the need for capturing permanent deformation, and a more effective characterization technique for unbound material is described. Following this new approach, conventional resilient modulus and permanent deformation determinations were examined for a variety of native soils and processed material (crushed stones). Implementation of the new characterization technique in analytical models is also discussed.