Performance Characteristics of Asphalt Rubber Mixtures Containing RAP and Warm Mix Asphalt Technology [Presentation]

The purpose of this study was to determine the effect of Reclaimed Asphalt Pavement (RAP) and Warm Mix Asphalt (WMA) technology on the performance of asphalt rubber mixtures. A 12.5mm mixture was designed with an asphalt rubber binder and designated as the control. The same control mixture was then designed incorporating a 25% RAP content Each of the mixture designs (control and 25% RAP) were then repeated at a lower mixing and compaction temperature using a wax-based WMA technology.
The mixtures were then evaluated to determine the impact of RAP and WMA technology on the performance of asphalt rubber mixtures in terms of stiffness (dynamic modulus), cracking resistance using the Overlay Test (OT) device, low temperature cracking resistance using the Asphalt Concrete Cracking Device (ACCD), and moisture susceptibility using the Hamburg Wheel Tracking Device (HWTD).

Mixture stiffness results indicated that control and 25% RAP mixtures exhibited similar stiffness, both with and without the WMA technology. The OT results indicated that cracking resistance of the mixtures decreased with the addition of RAP. The cracking resistance of the RAP mixture increased slightly with the addition of WMA technology. The low temperature cracking results indicated that the addition of RAP did not increase the potential for low temperature cracking in the mixtures. All of the mixtures tested passed the moisture susceptibility testing in the HWTD.