ffice of Infrastructure R&D U.S. Department of Transportation Federal Highway Administration High Reclaimed Asphalt Pavement Use in Asphalt Mixtures Canadian User/Producer Group for Asphalt Moncton, Canada November 15, 2009 Audrey Copeland and Gerry Huber FHWA and Heritage Research
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High Reclaimed Asphalt Pavement Use in Asphalt Mixtures
High Reclaimed Asphalt Pavement Use in Asphalt Mixtures. Canadian User/Producer Group for Asphalt Moncton, Canada November 15, 2009 Audrey Copeland and Gerry Huber FHWA and Heritage Research. Defining High RAP. R eclaimed A sphalt P avement Removed and/or reprocessed pavement - PowerPoint PPT Presentation
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Offi
ce o
f Inf
rast
ruct
ure
R&D
U.S. Department of TransportationFederal Highway Administration
High Reclaimed Asphalt Pavement Use in Asphalt Mixtures
Canadian User/Producer Group for AsphaltMoncton, Canada
November 15, 2009
Audrey Copeland and Gerry HuberFHWA and Heritage Research
U.S. Department of TransportationFederal Highway Administration
High RAP is defined as more than 25% RAP by weight of mix.
U.S. Department of TransportationFederal Highway Administration
RAP Efforts
• State of the Practice
• Primary Barriers and Remaining Challenges for Increased RAP Use
• National Efforts to Overcome Challenges
U.S. Department of TransportationFederal Highway Administration 4
States that Permit more than 25% RAP
U.S. Department of TransportationFederal Highway Administration
States that Use More than 20% RAP in HMA Layers
CA
AZ
CO
NM
TX
OK AR
LA
MO KY
AL GA
FL
VA
OH
MI
VTAK
MT
NV
MEWA
OR
UTKS
IDWY
ND
SD
MN
NE
WI
IAIL IN
MS
TNSC
NC
WV
PA
NY
CTNJDEMD
DC
MANH
PR
HI
RI
All layers (20% or more)Base and Intermediate layers onlyBase layer onlyDo not use more than 20% RAP
U.S. Department of TransportationFederal Highway Administration
So, why does < half of the nation use < 20% RAP?
• Blended virgin and RAP binder qualities especially for high RAP mixes and polymer modified binders
• Stiffening of the mix from high RAP quantities and resulting cracking performance.
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U.S. Department of TransportationFederal Highway Administration
Other “Roadblocks”
• Presence of dust
• Consistency/variability of RAP
• Lack of Quality Control (QC) by contractor
• Durability, especially in the surface layers– Raveling
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U.S. Department of TransportationFederal Highway Administration
Things are improving…
• Since 2007:– 21 States have increased amount of RAP
permitted
– 23 States now have experience with high RAP mixes
– 11 States have experience with high RAP and Warm Mix Asphalt mixes
U.S. Department of TransportationFederal Highway Administration 9
HMA Asphalt Pavement Recycling Expert Task Group
Advance the use of RAP in asphalt paving applications by providing highway agencies with critical information regarding the use of RAP, technical guidance on high-RAP projects, and direction on research activities.
The members consist of representatives from highway agencies, industry, and academia.
Website: www.moreRAP.us
U.S. Department of TransportationFederal Highway Administration 10
Current Guidelines• AASHTO M 323 Standard Specification
for SuperpaveTM Volumetric Mix Design
• Based on significant blending between virgin and RAP binder• Effects of plant production unknown• Calls for virgin binders that may be more expensive, hard to get• Blending chart analysis is time-consuming!
Recommended Virgin Asphalt Binder Grade Percent (%) RAPNo change in binder selection < 15Select virgin binder grade one grade softer than normal 15 – 25
Follow recommendations from blending charts > 25
U.S. Department of TransportationFederal Highway Administration 11
Issues to Consider when Increasing RAP
• Additional Processing & Quality Control (QC)
• Characterizing RAP
• Changing Binder Grade
• Mix Design
• Blending/Co-mingling of Virgin and RAP Binder
• Performance
U.S. Department of TransportationFederal Highway Administration
• Mill Intelligently
• Processing RAP
• Stockpile Management
Processing and Quality Control
U.S. Department of TransportationFederal Highway Administration
on VMA and asphalt content– Combined aggregate properties must meet consensus
requirements
U.S. Department of TransportationFederal Highway Administration 1414
Investigation of Properties of Plant Produced RAP Mixtures
• Assess current guidelines for RAP usage by determining low and high temperature properties of plant-produced HMA with varying RAP contents and virgin binder grades
• Investigate virgin and RAP binder blending during plant production