Evaluation of high RAP-WMA asphalt rubber mixtures

Abstract

This study focused on evaluating the stiffness, fatigue cracking, reflective cracking, rutting, moisture damage, and workability of asphalt rubber (AR) surface mixtures with reclaimed asphalt pavements (RAP) contents up to 40% with and without a warm mix asphalt (WMA) technology. RAP increased the stiffness of the mixtures; however, WMA mitigated that increase. The addition of RAP had an adverse effect on the resistance to fatigue and reflective cracking of the mixtures. This effect was magnified with the use of WMA regardless if RAP was incorporated in the mixture. Therefore, it was recommended to further investigate the proper drop in temperatures for AR mixtures that incorporate WMA. All mixtures passed the rutting and moisture damage test. The WMA technology improved the workability of the mixtures.

Keywords:

• asphalt rubber
• gap graded
• reclaimed asphalt pavement
• warm mix asphalt
• fatigue

Acknowledgements

The authors acknowledge Mike Nichols of Aggregate Industries and Mark Gabriel of All States Asphalt, Inc. for supplying the aggregates and asphalt rubber binder for this project, respectively. The authors also thank Chris Strack, Sonneborn, Inc. for the supply of WMA technology for this study. Finally, the authors thank UMass Dartmouth undergraduate research assistant Mr. Michael Roussel for his assistance with the laboratory testing for this project.