Characterization of Field-Produced HMA Mixtures from Nevada for Mechanistic-Empirical Pavement Design
AuthorFeaster, Teresa Christine
AdvisorHajj, Elie Y
Civil and Environmental Engineering
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The Nevada Department of Transportation (NDOT), with the help of the Western Regional Superpave Center (WRSC) began steps toward implementing the Mechanistic-Empirical Pavement Design Guide (MEPDG). NDOT is transitioning from AASHTO 1993 design methods to the newer state of the practice method. The MEPDG incorporates the mechanistic-empirical (M-E) pavement models to predict pavement damage as a function of specific traffic, materials and environmental inputs. The use of M-E based methods makes it possible to optimize the design and to more fully ensure that specific distress types will be limited to values less than the failure criteria within the design life of the pavement structure. To begin implementation 26 field produced mixtures have been sampled from behind the paver, since 2005, throughout the state of Nevada. Each mixture has a Contract designation and will be evaluated using laboratory performance testing for the binders viscosity, dynamic modulus, rutting regression coefficients using the Repeated Load Triaxial (RLT), and fatigue regression coefficients using the Flexural Beam Fatigue tester. Currently the MEPDG prediction models are nationally calibrated and require local or regional calibration to predict pavement performance more accurately. This implementation study is the first steps toward local calibration for Nevada. Each of the laboratory evaluations will be grouped using a 95% confidence interval to see if the Contracts can all be grouped together or separate groups for binder grade, District divisions within NDOT, Type 2 or 2C mixtures, or by aggregate and/or binder source. Viscosity groups found include binder grade, a District and two binder sources. Dynamic modulus values could be grouped together by District division and six different binder and aggregate sources each. Rutting coefficients were grouped by District, two binder sources, and an aggregate source. Fatigue coefficients can be grouped together for all the Contracts tested and by binder grade. Each of the Contracts for a group will be averaged for the corresponding input and provided to NDOT as inputs into the MEPDG to begin local calibration.