Field Performance of RAS Test Sections and Laboratory Investigation of Impact of Rejuvenators on Engineering Properties of RAP/RAS Mixes

In the last several years, recycled asphalt shingles (RAS), in addition to reclaimed asphalt pavement (RAP), have been widely used in Texas. The use of RAS can significantly reduce the cost of asphalt mixtures, conserve energy, and protect the environment. However, one of the major concerns is poor cracking resistance of RAS mixes due to super stiff asphalt binder in the RAS. This research focused on field performance of RAS test sections and the benefit of using rejuvenators in improving cracking resistance of RAS(/RAP) mixes. In addition, a simple cost analysis was performed to investigate the cost-benefits of using rejuvenators. It was found that both increasing design density (leading to higher virgin binder content) and using soft virgin binders (e.g. PGXX-28) can improve cracking resistance. With respect to improving cracking resistance of RAS mixes, the three rejuvenators evaluated in this research are all effective. Furthermore, the incorporation of rejuvenators also improved the moisture susceptibility and rutting resistance of the mixtures containing recycled materials. Apparently, additional tests and analyses are necessary. Specifically, field test sections with different types of rejuvenators should be constructed for further evaluation. Additionally, the observed field performance indicated that cracking performance is influenced by many factors, such as traffic, climate, existing pavement conditions for asphalt overlays, and pavement structure and layer thickness. It is extremely difficult to propose a single cracking requirement for all applications. There is a need to develop a RAP/RAS mix design and performance evaluation system for project-specific service conditions, including traffic, climate, existing pavement conditions, etc.


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Media Info

  • Media Type: Web
  • Pagination: 102p

Subject/Index Terms

Filing Info

  • Accession Number: 01526390
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/TX-14/0-6614-3
  • Created Date: May 6 2014 10:53AM