Evaluation of the Superpave gyratory compactor to assess the rutting resistance of asphalt mixtures

Premature rutting of asphalt pavements remains a concern to pavement engineers. In the last decade, several state and federal agencies have performed research projects and developed specifications to address rutting. Design and production of asphaltic mixtures that are resistant to rutting continues to be a top priority in pavement design. Asphalt mixture rutting is generally a costly failure that poses a considerable safety problem in terms of potential hydroplaning.; This research focuses on evaluating simple equipment that simulates field conditions for evaluating mixture resistance to permanent deformation during the mixture design process. A review of the literature showed that a Superpave gyratory compactor with shear resistance measurements as obtained in the Servopac is a promising device. The equipment simulates field compaction and traffic densification. It also can measure shear resistance, which may provide an insight into the resistance of mixtures to shear deformation.; We prepared laboratory and field mixtures with known performance and tested them with the Servopac Superpave gyratory Compactor. Supplementary tests on these mixtures were made with the Asphalt Pavement Analyzer (APA) and the Superpave Indirect Tension Tester (IDT) to allow comparison of the results.; Results of the analysis showed that the gyratory compactor with the shear measurement device can be used as a screening tool for asphalt paving mixtures. Substandard mixtures were identified and specification limits were set for the mixtures tested using the slope of the gyratory shear and the strain to the minimum gyratory shear resistance of a proposed modified procedure of comparison to simulate pavement critical loading conditions. Based on the analysis, mixtures were prepared and Marshall stability and flow tests were performed at he FDOT to set specification limits for using the equipment as a simple tool for evaluating asphalt mixtures during design.; As an addendum, the proposed Superpave(TM) tests were performed on some of the mixtures and simple parameters were derived for further evaluation for the evaluation of the rutting performance of hot mix asphalt (HMA) mixtures.