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Green Roadway Design from a Pavements Perspective

Green Roadway Design from a Pavements Perspective. Rene’ Renteria, P.E. ODOT Pavement Design Engineer April 13, 2010. Green Pavements Initiatives. Incorporation of Recycled Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) Warm Mix Asphalt (WMA). Recycling of Asphalt Pavement.

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Green Roadway Design from a Pavements Perspective

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  1. Green Roadway Designfrom a Pavements Perspective Rene’ Renteria, P.E. ODOT Pavement Design Engineer April 13, 2010

  2. Green Pavements Initiatives • Incorporation of Recycled Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) • Warm Mix Asphalt (WMA)

  3. Recycling of Asphalt Pavement • Made a practice in early 1970’s • Long-term performance is proven

  4. Recycling of Asphalt Pavement • Significant Reduction in Greenhouse Gas • Emissions • Currently average ~12.5% nationwide • An Increase to 25% = 10% reduction in GHG • (= 2,000,000 Tons Annually!)

  5. Recycling of Asphalt Pavement

  6. RAP Use on ODOT Projects • 2008: 225,000 tons • 2009: 450,000 tons

  7. RAS Background • Asphalt shingles are the most common roofing material nationwide • ≈11 million tons of asphalt shingle waste is generated each year: • Manufacturer waste  ≈10% • Post consumer waste (tear-off)  ≈90% • Great market potential for recycling

  8. NEED: Stiff pavement when it is hot to prevent rutting. AND: Soft pavement when it is cold to prevent cracking.

  9. OSU Study Overview • Investigate how Recycled asphalt materials affect the stiffness and softness of the blended binder • Recycled Asphalt Pavement (RAP) • Recycled Asphalt Shingles (RAS) • Recommend changes to ODOT specifications and special provisions for a pilot study

  10. OSU Study Evaluate properties of original and reclaimed binders Test asphalt pavements mixtures with various proportions of RAP and/or RAS Extract & Evaluate properties of the resultant blended binders Compare properties of virgin and blended binders – How much have the properties changed?

  11. Initial Study Findings RAS blend only & no RAP = More stiff, causing cracking  Negative impact on the blended binder 10% RAP & 5% RAS = No change in binder properties 30% RAP & 5% RAS = Significant negative effect on binder properties  possible poor pavement performance

  12. Course of Action Two ODOT pilot projects planned for 2010, mandated use of RAS (1 Eastside & 1 Westside of Cascades) The pilots will require 5% RAS and allow up to 20% RAP in HMAC mix Monitor pilot project for construction issues and performance issues for a minimum of two years

  13. Course of Action, cont. • Modify our specifications: should we look at adjusting the properties of virgin binder? Not now but perhaps in the future. • Modify our testing procedures including: • Mix design protocol • Determining binder content of RAS • Allow RAS in pavements (permissive specification)?

  14. Warm-Mix Asphalt • May Reduce Mixing Temperatures (50º to 100º F) Temp = 320º F Temp = 245º F

  15. ODOT WMA For 2009 • US 101 @ Latimer Road • US97: OR31 Hwy Jct - SCL Crescent • OR22: Independence Hwy - Willamette River • WMA placed on OR 51 • US197: The Dalles - Eight Mile Creek

  16. ODOT 2009 WMA Projects

  17. Reports of Cracking • US97 and US197 have transverse cracking after first winter season • Evident within HMA and WMA on US97 • December 2009 had reports of extreme cold • Investigation/Testing

  18. WMA Plans for 2010 • Work with ODOT Mgmt. & Industry to bring WMA onto ODOT pavement projects • Reviewing projects completed in 2009 • Recent meeting in February with Industry to discuss what’s been learned • Modifications to Specs and Process • Adjustment to WMA temperature definition • QC/QA Testing guidelines • Mix design process

  19. Questions?

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