Experimental Study on the Compaction Characteristics of Foamed Warm Mix SMA Based on the Shear Gyratory Compaction Method

The foamed warm mix asphalt (WMA) technology is a new construction method that decreases the viscosity of the asphalt binder and increases the workability during the construction phase. Conventional hot mix asphalt is typically produced at temperatures from 150°C to 170°C, while WMA is produced at 120°C~140°C. For WMA, quantitative analysis plays a key role in understanding the workability and compaction during the construction phase. Besides WMA, stone matrix asphalt (SMA) is designed and analyzed according to the Chinese standards. In this study, the shear gyratory compaction (SGC) test machine was employed to mold specimens for hot mix SMA, warm mix SMA and hot mix (warm compaction) SMA and their densification curves are systematically analyzed. Moreover, the compaction energy index and slope of densification curves are employed to reflect the information regarding the inherent compaction workability of asphalt mixtures. The results indicate that the SGC densification curves can reflect mixture compaction characteristics and that hot mix SMA and WMA have similar workability, while hot mix (warm compaction) asphalt has inferior performance in it.