Development of Quality Standards for Inclusion of High Recycled Asphalt Pavement Content in Asphalt Mixtures - Phase V

Public agencies encourage the use of recycled asphalt materials (RAM) in constructing asphalt pavements to the maximum extent possible with an equal performance. Low temperature cracking potential is a primary concern with high RAM mixtures. To minimize a low temperature cracking, various rejuvenators and softer binders have been utilized in the past. Although the current Iowa DOT’s specification allows RAP materials up to 30% with softer binders, limited construction projects, which utilized more than 20% RAP materials, have been performed. The main purpose of this research is to develop a comprehensive asphalt recycling strategy for high RAM mix up to 50% in consultation with surrounding state DOT's, cities and counties by performing the following tasks: (1) develop an approval process for rejuvenators that incorporates long-term aging of the material; (2) perform a feasibility study of a fractionation of RAP materials in two stockpiles; (3) consider increasing the maximum RAM percentage up to 50% for some mixes. Investigate various economic conditions that determine whether the increased stiffness from the RAM can be economically off-set with rejuvenators and softer binder grades; (4) evaluate Warm Mix Asphalt (WMA) with high RAM. WMA containing RAM showed similar cracking and rutting resistance performance compared to HMA. Additional study of WMA with RAM could be useful to verify if it meets both economic and sustainability requirements; (5) adopt a test procedure like a Semi-Circular Bending-Illinois Flexibility Index Test (SCB-IFIT) for high RAM mixtures up to 50% as a performance test after evaluating various testing procedures based on sample preparation, specimen conditioning and testing, training needs, new equipment cost, repeatability and field validation; (6) monitor high RAM project sites to determine the effectiveness and limitations of design, construction and performance of high RAM mixtures and develop quality assurance/quality control (QA/QC) aspect of using softer binders and rejuvenators; and (7) develop a comprehensive asphalt recycling strategy encompassing high RAM mix up to 50%, Cold In-place Recycling (CIR) and Hot In-place Recycling (HIR) in consideration of both economic and sustainability analyses.

• Record URL:
  https://ideas.iowadot.gov/subdomain/ideas-main/end/node/3768?qmzn=iKFrYf#Active

Language

• English

Project

• Status: Active
• Funding: $348841
• Sponsor Organizations:

  Iowa Department of Transportation

  800 Lincoln Way
  Ames, IA  United States  50010
• Managing Organizations:

  University of Iowa, Mechanical and Industrial Engineering

  3100 Seamans Center for the Engineering Arts and Sciences
  Iowa City, Iowa  United States  52242
• Project Managers:

  Buss, Ashley

• Performing Organizations:

  University of Iowa, Mechanical and Industrial Engineering

  3100 Seamans Center for the Engineering Arts and Sciences
  Iowa City, Iowa  United States  52242
• Principal Investigators:

  Lee, Hosin

• Start Date: 20230901
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Asphalt mixtures; Asphalt pavements; Mix design; Quality control; Recycled materials; Rejuvenators; Standards; Warm mix paving mixtures
• Subject Areas: Design; Highways; Materials; Pavements;

Filing Info

• Accession Number: 01909011
• Record Type: Research project
• Source Agency: Iowa Department of Transportation
• Files: RIP, STATEDOT
• Created Date: Feb 20 2024 6:02PM