1 green roadway design from a pavements perspective rene’ renteria, p.e. odot pavement design...
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Green Roadway DesignGreen Roadway Designfrom a Pavements from a Pavements
PerspectivePerspective
Rene’ Renteria, P.E.ODOT Pavement Design
EngineerApril 13, 2010
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Green Pavements Initiatives
Incorporation of Recycled Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS)
Warm Mix Asphalt (WMA)
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Recycling of Asphalt Pavement• Made a practice in early 1970’s
• Long-term performance is proven
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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!)
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Recycling of Asphalt Pavement
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RAP Use on ODOT Projects
2008: 225,000 tons 2009: 450,000 tons
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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
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NEED: Stiff pavement when it is hot to prevent rutting.
AND: Soft pavement when it is cold to prevent cracking.
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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
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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?
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-40 -20 0 20 40 60 80 100 120 140 160 180 200
Temperature, degrees Fahrenheit
Asp
halt
Bind
erBinder from Mixture with 50% RAP & 5% RAS
-9.4 +178.7Binder from Mixture with 20% RAP & 5% RAS
-4.0 +193.1Binder from Mixture with 30% RAP & 5% RAS
-6.7 +191.3Binder from Mixture with 0% RAP & 5% RAS
+3.2 Binder from Mixture with 40% RAP & 5% RAS +190.4
-25.6 +161.6As-Received "PG64-28" Binder
-21.1 +153.5Binder from Mixture with 0% RAP & 0% RAS
-20.2 +158.9Binder from Mixture with 10% RAP & 5% RAS
-22.0 +158.0As-Received "PG70-28" Binder
+1.4 +185.0
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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
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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
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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)?
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Warm-Mix Asphalt• May Reduce Mixing Temperatures (50º to 100º F)
Temp = 320º F Temp = 245º F
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Warm Mix Demonstration Projects in the U.S. as of Jan. 2007
Warm Mix Demos
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Warm Mix Demonstration Projects in the U.S.
Warm Mix Demos
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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
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ODOT 2009 WMA Projects
PROJECT WARM-MIX TONS / RAP TEMP
SYSTEM (Binder) (Deg F)
US101 @ Latimer RdFoamed -
Terex1,400 / 20%
PG 64-2230
US97: OR31 Jct - SCL Crescent
Foamed - Aquablack
44,000 / 20%PG 70-28ER
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OR22: Independence Hwy - Willamette Rvr & OR51
Additive - Evotherm
5,500 / 30%PG 64-22
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US197: The Dalles - Eight Mile Cr
Foamed - Aquablack
17,000 / 30%PG 64-28
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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
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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
Questions?