Use of Superpave gyratory compaction data for rutting prediction

This paper presents the estimation results of an improved nonlinear rutting progression model for asphalt concrete mixes. Rutting is modeled as a function of traffic, temperature, and mix characteristics, including voids filled with asphalt, asphalt content, in-place air voids, surface area, and the densification slope. Mixed effects, an advanced statistical technique that allows the consideration of several sources of randomness and autocorrelated disturbances, is used for the estimation of the model parameters. The estimation results with measurements from WesTrack indicate that the model is statistically significant. Further, the model correctly anticipates the dramatic failure of the WesTrack replacement sections (approximately 10-20 mm in a few days). Mixture rutting resistance is linked to the aggregate resistance to densification, as measured by the densification slope in the Superpave gyratory compactor. The model may provide a basis for identification of probable mix performance in the field with the help of only normal quality assurance tests and in-place density measurements. Finally, since the parameters related to asphalt content are binder specific, the specification of the model provides a framework that can be expanded to include other asphalt binder characteristics.