Laboratory characterization of Nevada's HMA mixtures for mechanistic empirical design

The release of the Mechanistic-Empirical Design Guide for New and Rehabilitated Pavement Structures (M-E design guide) generated a new standard for designing and analyzing pavement structures. It is expected to replace the commonly used empirical design methodologies. The M-E design guide provides a performancebased design to the transportation community. It has the capability of analyzing in situ pavement and predicting the remaining life with performance prediction. With that capability, it is a design guide that will reach more users in academia and industry. However, time and resources are needed to accomplish a rational and accurate design and analysis using the M-E design guide.; In an effort to accelerate the adoption of the new M-E pavement design guide in Nevada, the Nevada Department of Transportation (NDOT) is conducting each year research studies on fifteen pavement projects constructed in three different districts in Nevada. These districts are selected based on different traffic and environmental conditions.; This research evaluated the laboratory rutting and fatigue performance and the dynamic modulus of four HMA mixtures in their dry and conditioned state, after one freeze-thaw cycle, designed using the Hveem mix design method. The various mixtures used in this study were sampled from behind the paver during construction of contracts 3239, 3248, 3257 and 3214. All four projects were Hveem designed mixtures with polymer modified asphalt binder. Mixtures from contracts 3239 and 3248 were manufactured with PG64-28NV asphalt and Type 2 and Type 2C dense graded mixtures, respectively. Projects 3257 and 3214 mixtures included PG76-22NV, Type 2 and Type 2C dense graded mixtures, respectively.; Laboratory experiments were conducted at the Western Regional Superpave Center (WRSC) at the University of Nevada Reno (UNR). The flexural beam fatigue test and the repeated load triaxial test were used to evaluate the resistance of the various asphalt mixtures to fatigue and rutting, respectively. To this end, laboratory performance models were developed for the dry and wet conditions of the mixtures. The dynamic modulus test was used to evaluate the dynamic modulus master curve at various temperatures and time of loading. The performance model in conjunction with the dynamic modulus master curve of the HMA mixtures serve as important inputs in the M-E design methodology for flexible pavement.; Additionally, mechanistic analysis was performed as an attempt to determine the pavement responses for each project. Four pavement structures, representing the constructed sections in the field were analyzed under an axle load of 18 kips. This load is the maximum axle load allowed by NDOT. The responses of the asphalt pavement were calculated using the ELSYM 5 software and the results were plugged in the performance models to evaluate the number of load repetitions against the criteria set for fatigue and rutting. The time and temperature dependent behavior of the HMA layer as the truck moves at 45 mph is incorporated by using the dynamic modulus of the HMA mixture at the corresponding speed and temperature. The base course and subgrade layers were treated as linear elastic materials.