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?