Increasing Asphalt Recycling to Reduce Paving Costs, Improve Pavement Longevity, and Reduce Environmental Impact

Recycling highway construction materials and minimizing the use of virgin materials can reduce the pavement life cycle costs, improve highway network conditions, conserve natural resources, and protect the environment. Although using recycled asphalt pavements (RAP) is beneficial in many aspects, the primary concern when using high RAP mixes lies in asphalt mixtures' altered long-term durability properties. Aged binder in RAP is less ductile than a virgin binder and gives rise to failure under repeated high axle loads and thermal effects. For this reason, in Oregon, the use of RAP in asphalt mixes is currently limited to about 30% by weight of the mix. For asphalt mixtures with a higher percentage of RAP (higher than the current limit), using rejuvenator and warm-mix asphalt (WMA) additives are the major strategies for improving the resistance to cracking. Rejuvenators and WMA can restore the physical and chemical properties of the aged binder and make the mix softer by reducing the viscosity of the mix (Roberts et al. 1996; Tran et al. 2012; Coleri et al. 2021). However, selecting the most effective rejuvenators and WMA technologies for Oregon, developing methods and guidelines for choosing the proper amount of additives in mix design, and ensuring appropriate mixing to achieve high RAP mixes (40% to 50% by weight of the asphalt mixture) without compromising the performance of the asphalt surfaced pavements is crucial. In addition, practices for better managing the RAP stockpiles at the asphalt plants (including process controls) need to be developed and implemented to achieve a higher level of uniformity in asphalt mixture production and construction with high RAP asphalt mixtures. Developing better RAP management procedures combined with rejuvenator and WMA usage are expected to allow significant increases in the RAP content of asphalt mixtures in Oregon.

Language

• English

Project

• Status: Active
• Contract Numbers:

  SPR 862

• Sponsor Organizations:

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Managing Organizations:

  Oregon Department of Transportation

  355 Capital St NE MS42
  Salem, Oregon  United States  97301
• Project Managers:

  Galvez, Cristhian

• Performing Organizations:

  Oregon State University, Corvallis

  101 Kearney Hall
  Corvallis, OR  United States  97331
• Principal Investigators:

  Coleri, Erdem

• Start Date: 20220901
• Expected Completion Date: 20260930
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Additives; Asphalt mixtures; Durability; Mix design; Recycled materials; Rejuvenators; Warm mix paving mixtures
• Geographic Terms: Oregon
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 01964172
• Record Type: Research project
• Source Agency: Oregon Department of Transportation
• Contract Numbers: SPR 862
• Files: RIP, STATEDOT
• Created Date: Aug 28 2025 11:05AM