This paper addresses the development and evaluation of a mix stability index referred to as the Gyratory Stability (GS). GS is measured from the compaction data by summing the cumulative energies dissipated in the compaction of a gyratory sample to N-design. A wide range of commonly used mixes in the State of Idaho was selected for evaluation, a total of seventeen mixes. In addition to these mixes, seven different field mixes were procuredfrom ongoing projects. Mixes were tested for dynamic modulus (E*) and flow number (FN); Rutting was measured with the Asphalt Pavement Analyzer (APA). Further, E* test results were used in the 2002 AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) as level 1 inputs, to predict permanent deformation for these mixes. It was found that GS ranked mixes similarly to the APA and FN tests and MEPDG results. In addition, GS was evaluated for quality control purposes. It was found that GS captures changes in mix properties. Overall, results indicate that the GS has the potential to be used as a screening tool for asphalt mix design, especially to decide upon the acceptance of the mix aggregate structure during the mix design process, and as a quality control tool.
Abstract