Conceptual Framework for Material Characterization in Mechnaistic-Empirical Flexible Pavement Design

A conceptual framework for determining the type and amount of data necessary to successfully conduct materials characterization as part of mechanistic-empirical (M-E) flexible pavement design is presented. This approach is particularly useful for agencies that plan to pool efforts regionally to obtain the necessary M-E flexible pavement design inputs; however, an understanding of local materials limitations is critical to the success of using this approach. Materials inputs for M-E flexible pavement design include volumetric binder/mix properties, dynamic complex modulus, creep compliance and indirect tensile strength. The first step in forming the conceptual approach was to identify what some state transportation agencies are already doing to prepare for M-E pavement design implementation. An approach was formulated that consists of site evaluation of existing conditions, laboratory testing to obtain materials inputs, and analysis of inputs and resulting predicted performance. The final step consists of development of a database that contains mixture properties to be used as a materials catalog and consequently reduce the testing effort. Material datasets for a given location can be developed to identify the local or regional-specific inputs to M-E analysis. The framework was tested based on a case example with four mixtures from three northeastern US states and predicted rutting performance data was evaluated.