Material Characterization of Different Recycled Asphalt Pavement Sources

Using recycled asphalt pavement material has been favored over virgin materials in the light of the increasing cost of asphalt and the scarcity of quality aggregate. Most agencies established limits on the maximum percentage of reclaimed asphalt pavement (RAP) that can be used, ranging typically between 10 to 50%. With the introduction of the Superpave mix design, many questions were raised about the proper method of incorporating RAP in the Superpave. During service, the blend of aggregates and binders undergoes various physical and rheological changes that have to be considered in the design process to ensure that hot mix asphalt mixtures with RAP will perform very well. In this study, RAP samples were procured from four different locations and evaluated in terms of aggregate gradation, aggregate specific gravity and particle angularity. Binders were recovered from each RAP source and the rheological properties were evaluated using the Dynamic Shear and Bending Beam Rheometers. Taking variability of the measured values into account, statistical analysis of the individual test results suggests that while there were similarities in some measured characteristics such as binder content, aggregate gradation and binder stiffness between two or even three of the RAP sources, the characteristics of RAP materials in general can not be assumed to be similar for the purposes of asphalt mixture design. It is found that general assumptions should be used with caution, for example, that the grade of virgin binder to be used in a mixture containing RAP does not need to be modified or shifted downward in stiffness if the percentage of RAP used in a mixture is less than 15% by weight. Indeed, the results of binder rheological testing in this study showed that the measured stiffness of the hardest extracted RAP binder is more than twice that measured for the softest sampled RAP binder. It is concluded that the properties of the aggregate and binder in RAP materials should be evaluated completely before design and regularly during production to ensure the satisfactory performance of the constructed pavement.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/16762797
• Authors:
  • Khosla, N Paul
  • Nair, Harikrishnan K
  • Visintine, Beth
  • Malpass, Glen
• Publication Date: 2009

Language

• English

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 13-24
• Serial:
  • International Journal of Pavements
  • Volume: 8
  • Issue Number: 1-2-3
  • Publisher: University of Mississippi, University
  • ISSN: 1676-2797

Subject/Index Terms

• TRT Terms: Aggregate gradation; Binder content; Hot mix asphalt; Mix design; Pavement performance; Reclaimed asphalt pavements; Recycled materials; Rheological properties; Superpave
• Subject Areas: Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways; I31: Bituminous Binders and Materials;

Filing Info

• Accession Number: 01383427
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 22 2012 3:36PM