Issues Pertaining to Use of Superpave Gyratory Compactor

Agencies, industry, academia, and others are rapidly implementing the products of the asphalt research portion of the Strategic Highway Research Program, products collectively referred to as Superpave. One of the principal products has been the Superpave gyratory compactor (SGC). The results of an experimental program, conducted at the Asphalt Institute Research Center in Lexington, Kentucky, and aimed at assessing the effect of various compaction parameters on SGC test results, are outlined. Compaction results were most often different when different mold diameters were used. The length of the laboratory short-term aging period also affected test results. Compaction temperature was a critical factor when a modified binder was used. SGC affected moisture-susceptibility test results although specimens fabricated using SGC were successfully demonstrated to predict moisture damage using the AASHTO T283 protocol. The experiment also compared the compaction characteristics of several different units. This comparison demonstrated minor to moderate differences in test results when the same mix was evaluated.