Abstract
Crumb rubber modified (CRM) bituminous binders have demonstrated significant enhancements in asphalt rheological and mechanical properties, establishing their effectiveness in improving the performance and durability in asphalt surfacing applications. While significant improvements are realized at higher dosages, more recent research efforts are considering low-dosage CRM binders to improve the aging resistance of dense graded asphalt (DGA) surfacing for local roads. This research compared the properties of low-dose CRM binders (5% to 15%) in DGA using a mixture-based Glover-Rowe parameter (GRP), which used viscoelastic principles to capture the stress relaxation effects at 5 ℃ and 25 ℃, as a measure of low and intermediate temperature performance, respectively. Compacted asphalt specimens were prepared for four-point bending flexural modulus testing, which were then subjected to thermo-oxidative oven aging procedures to simulate field aging. The relative aging effects of the mixtures were then compared through changes to the mixture-based GRP. It was determined that CRM DGA can provide considerable aging resistance benefits, where positive enhancements were realized at the 10% to 15% dosages for both field and terminal blends. However, future work should consider additional aging durations, and photo-oxidative aging, to better distinguish differences in blending methods and the resulting anti-aging effect.