Laboratory Performance Testing for National Center for Asphalt Technology Pavement Test Track

An experimental facility has been constructed near the campus of Auburn University in Alabama for the purpose of conducting research to extend the lives of flexible pavements. Experimental sections on the 2.8-km Pavement Test Track are cooperatively funded by external sponsors, most commonly, state departments of transportation, with operation and research managed by the National Center for Asphalt Technology (NCAT). Forty-six different flexible pavements were installed at the facility, each at a length of 61 m. Materials and methods unique to the section sponsors were imported during construction to maximize the applicability of the results. A design lifetime of truck traffic is now being applied over a 2-year period, with field performance documented weekly. Sponsors typically compare the performance of two or more sections constructed with different materials or by different methods to obtain information that can be used to build future pavements with the greatest amount of rut resistance. In addition to assessing alternatives for sponsors, NCAT is responsible for guiding the overall effort in a direction that will address policy issues for the highway industry as a whole. Specifically, laboratory methods that have the potential to predict rutting when they are used before and during construction are being compared with field performance for every experimental mix so that the most suitable method(s) can be recommended. Results from loaded wheel testing are presented to encompass the empirical approach, while results from shear and creep testing facilitate mechanistic analyses. The success of each method will ultimately be measured by comparing the performance in the laboratory with the performance on the experimental roadway.