Minimum Required Virgin Binder Content for Recycled Superpave Mixtures

Use of recycled materials such as recycled asphalt pavement (RAP) and recycled asphalt shingle (RAS) has become widespread recently due to rising costs of virgin binder and increased attention to sustainability. Although there are some guidelines regarding use of RAP and RAS in hot mix asphalt (HMA), their effects on mixture performance, especially on mixtures containing RAS, are not thoroughly understood. In this research, three recycled Superpave mixture designs from the Kansas Department of Transportation (KDOT) with 9.5 mm (SR-9.5A) and 19 mm (SR-19A) Nominal Maximum Aggregate Size (NMAS) were selected as control mixtures. Mixtures containing higher percentages of recycled materials (RAP and RAS) were developed using KDOT blending charts. A total of nine mixtures with varying virgin binder contents were designed and assessed for fatigue cracking propensity using dynamic modulus and Simplified Visco-Elastic Continuum Damage (S-VECD) direct tension fatigue tests. Results confirmed that mixtures with different RAP source performed differently and there is a significant relationship between predicted fatigue damage characteristics and aggregate source. Mixtures with virgin binder content of 65% and above showed better performance properties as compared to the recycled mixtures with lower virgin binder content. Based on the results of this study, 65-85% was recommended as the acceptable range of virgin binder content for Kansas mixtures.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AFK50 Standing Committee on Structural Requirements of Asphalt Mixtures.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Tavakol, Masoumeh
  • Hossain, Mustaque
  • Heptig, Blair
• Conference:
  • Transportation Research Board 96th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2017-1-8 to 2017-1-12
• Date: 2017

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 15p
• Monograph Title: TRB 96th Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Binder content; Fatigue cracking; Hot mix asphalt; Reclaimed asphalt pavements; Recycled materials; Shingles; Superpave
• Uncontrolled Terms: Virgin materials
• Geographic Terms: Kansas
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 01628582
• Record Type: Publication
• Report/Paper Numbers: 17-02627
• Files: TRIS, TRB, ATRI
• Created Date: Mar 7 2017 5:27PM