Evaluation of Dynamic Modulus Values of Oklahoma Mixes

Abstract

The new mechanistic-empirical pavement design guide (M-EPDG) uses dynamic modulus value (E*) as the material characterization parameters for asphalt mixtures. (E*) is an absolute value of a complex number that relates stress to strain for linearly viscoelastic materials under sinusoidal loading. The objective of this study was to determine if independent mix variables had significant effect on E*, build master curves and recommend a default set of E* values for Oklahoma mixes. Cold feed belt samples of S3 and S4 mixtures were sampled throughout the state. Mixtures were selected to include the major aggregate types in Oklahoma and to cover each region of the state. Replicate samples were tested for E* at optimum asphalt content with PG 64-22, PG 70-28 and PG 76-28,the commonly used binder grades in Oklahoma. Test were performed in accordance with AASHTO TP 62-03. Binder grade was found to have a significant effect on dynamic modulus . Mix type, quarry region and aggregate type did not have a significant effect on dynamic modulus. Default dynamic modulus values were recommended for use in the M-EPDG for Oklahoma mixtures.