Implementation of Superpave Mix Design and Analysis Procedures for the State of Nevada: Volume V

This research effort started in mid 1990's to evaluate the performance ofSuperpave mixtures under Nevada's conditions and to assess the possibility of implementing the Superpave mix design procedure. Field test sections were constructed to compare the performance ofSuperpave mixtures with the performance of Hveem under the same traffic and environmental conditions. Based on the field performance of several Superpave mixtures throughout the state of Nevada during the late 1990's, NDOT decided to modify the Superpave volumetric mix design method and construct two test sections side-by-side with the conventional NDOT Hveem mixtures on three projects. The modifications ofthe Superpave volumetric mix design included: a) eliminate the restricted zone requirement on aggregate gradation, b) include a minimum requirement on Hveem stability, c) verify potential performance in rutting with the AP A, and d) include a minimum dry tensile strength of 65 psi and a retained tensile strength ratio of70%. Using the modified Superpave volumetric mix design, NDOT constructed three test sections: two on I-80 in the northern part ofthe state in 2001 and 2003 and one on I-15 in the southern part ofthe state in 2002. Each test section was built as part ofa Hveem designed project which allowed for the direct comparison ofthe performance of mixtures designed with the modified Superpave and NDOT Hveem methods. This report summarizes the laboratory evaluation ofthe mixtures from the two sections on each of the projects and the field performance of the sections. The laboratory evaluations assessed the resistance of the mixtures to the failure modes of rutting, thermal cracking, fatigue, and moisture damage. The field performance included the measurement of rutting data on the field sections