Description
It is an ongoing challenge in the flexible pavement industry to create new and improved modifications to construction materials. A concept with growing popularity in many parts of the world is the addition of recycled ground tire rubber (GTR) to the liquid asphalt component of asphalt concrete pavement. However, modification with GTR has not been accepted nationally and several highway agencies remain skeptical about performance of this material. This skepticism is sustained by the variability in current methods of use associated with GTR modification.
This study focused on the evaluation of various test methods that are used to characterize GTR modified asphalt binders’ viscoelastic properties and investigating the variability in measured properties with respect to the change of the measuring geometry type. Detailed binder testing indicates that current Superpave test methods are not adequate to capture the rheological behavior of GTR modified binders. Meanwhile, the cylindrical system was able to capture rheological properties of GTR modified binders successfully at wide range of temperatures.
