Comparison of rheological properties and hot storage characteristics of asphalt binders modified with devulcanized ground tire rubber and other modifiers

- A devulcanized ground tire rubber (DGTR) was utilized in this study.
- Three base asphalt binders, and three polymers were used to produce PG76 binders.
- Hot storage properties, creep and creep recovery, and multiple stress creep recovery, etc. were tested.
- PG76 binders modified with DGTR had approaching viscosity values compared to GTR or SBS modified binders.
- Binders modified with DGTR exhibited lower phase separation tendency than GTR or SBS modified binders.

The ground tire rubber (GTR) modified binder has been affirmed to improve resistance to rutting, moisture susceptibility, low temperature cracking and durability of asphalt pavement. However, the liable phase separation of GTR modified asphalt binders results in a big issue at construction site. Therefore, an alternative crumb rubber, devulcanized ground tire rubber (DGTR), is manufactured with devulcanization process and as an additive to substitute for GTR or styrene-butadiene-styrene (SBS) in PG76 binders preparation process. The objective of this study was to compare the rheological properties and hot storage characteristics of PG76 asphalt binders produced with DGTR and two alternative polymers for future applications. The Brookfield Rotational Viscometer, Dynamic Shear Rheometer, and hot storage test were performed with all modified asphalt binders. The results indicated that PG76 binders modified with DGTR had approaching apparent viscosity values compared to GTR or SBS modified binders. In addition, the application of DGTR could reach the similar modification effect on the High PG critical temperature as well as GTR modified binders with same concentration. While those binders modified with DGTR exhibited remarkable lower tendency of phase separation than other modified binders regardless of base binder source. Moreover, similar trends were observed from the characteristics of creep and creep recovery, and Multiple Stress Creep and Recovery (MSCR) of all modified binders.