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Office of Pavem
ent Techno
logy
Office of Pavem
ent Techno
logy
U.S. Department of TransportationFederal Highway Administration
Sustaining our Highways:Sustaining our Highways:A National Perspective on RAP Usage & Best A National Perspective on RAP Usage & Best
Practices for Recycled Asphalt PavementsPractices for Recycled Asphalt Pavements
Audrey CopelandAsphalt Pavement Engineer
Pavement Performance Prediction Symposium July 16, 2008Laramie, WY
2U.S. Department of TransportationFederal Highway Administration
Presentation OutlinePresentation Outline
• What is RAP?– Hasn’t it been used
for years?– Economic drivers
• State-of-the practice– State DOTs– Contractors– Major concerns and
barriers
• National perspective– Objectives and
essential steps for increasing pavement recycling
– FHWA involvement and activities
• Constructability– Best practices
3U.S. Department of TransportationFederal Highway Administration
What is RAP?What is RAP?
• Reclaimed Asphalt Pavement
• Removed and/or reprocessed pavement materials containing: ~ binder (5%)~ aggregates (95%)
4U.S. Department of TransportationFederal Highway Administration
Reclaimed Asphalt Pavement (RAP)Reclaimed Asphalt Pavement (RAP)
Sources of RAP– Milling– Pavement removal– Plant waste
Most Common Uses– Addition to HMA– Aggregate in cold-mix– Granular base– Fill or embankment
material
5U.S. Department of TransportationFederal Highway Administration
HasnHasn’’t RAP been used for years?t RAP been used for years?
1970s – Begins a recycling boom
1980s – 1990s – Technical Guidance• NCHRP• FHWA
6U.S. Department of TransportationFederal Highway Administration
HasnHasn’’t RAP been used for years?t RAP been used for years?
1990s – Superpave developed• New mix design system• New gradation controls• State DOTs limit RAP allowed
7U.S. Department of TransportationFederal Highway Administration
HasnHasn’’t RAP been used for years?t RAP been used for years?
• NCHRP Project 9-12 Recommended Use of RAP in Superpave
• Contractors implement improved techniques– RAP processing – Gradation control
2000s – Superpave Implemented
Office of Pavem
ent Techno
logy
Office of Pavem
ent Techno
logy
U.S. Department of TransportationFederal Highway Administration
Economic Drivers for Using RAPEconomic Drivers for Using RAP
Growth in recycling occurs when it is economical to do so.
9U.S. Department of TransportationFederal Highway Administration
Change in Producer Prices Change in Producer Prices for Construction Segments for Construction Segments
100
110
120
130
140
150
160
170
12/03 12/04 12/05 12/06 12/07
Highway and street construction: 66%Other heavy construction: 54%Nonresidential buildings: 37%Single-unit residential: 27%Consumer price index: 18%
Source: BLS (CPI, PPI)
10U.S. Department of TransportationFederal Highway Administration
Change in Producer Price Change in Producer Price Indexes (PPI) for Highway InputsIndexes (PPI) for Highway Inputs
100
150
200
250
300
350
400
450
12/03 12/04 12/05 12/06 12/07
#2 diesel fuel: 306%
Asphalt Paving Mixtures & Blocks: 70%
Concrete products: 36%
Consumer price index (CPI-U): 18%
Source: BLS (CPI, PPI)
11U.S. Department of TransportationFederal Highway Administration
Asphalt Production Cost CategoriesAsphalt Production Cost Categories
0
10
20
30
40
50
60
70
80
90
100
Material Plant Production Trucking Lay Down
Perc
ent (
%) o
f Cos
t
Greatest Potential for Cost Savings isin the Materials Category
12U.S. Department of TransportationFederal Highway Administration
Material Costs and Savings with RAPMaterial Costs and Savings with RAP
$64.20Total Virgin Materials
$8RAP (including milling, transportation, & processing)*
$30 (94%)Rock$600 (6%)Liquid Asphalt Cement
Cost ($) per ton (%mix)Material
* Brock, J.D. and Scott Thompson. “Plant Processing Strategies to Maximize RAP Use”. Presented at HMA Energy & Recycling Symposium, Austin, TX, October 22-23, 2007.
13U.S. Department of TransportationFederal Highway Administration
0
10
20
30
40
50
60
70
0% 10% 20% 30% 40% 50% 60%
Percentage of RAP
Dol
lars
($) p
er to
n
Savings with RAPSavings with RAP
$5.62
$8.43$16.86
$28.10
$64.20Total Virgin Materials
$8RAP (including milling, transportation, & processing)*
$30 (94%)Rock
$600 (6%)Liquid Asphalt Cement
Cost ($) per ton (%mix)Material
14U.S. Department of TransportationFederal Highway Administration
Why allow high RAP?Why allow high RAP?• Reduced costs
• For example…– Upfront cost impact - If specification allows high RAP,
contractors may submit different bid prices on plant mix items or frequency of price adjustments and delays.
– Future cost impact – higher RAP pavement has different life-cycle properties
• The cost effectiveness of higher-RAP mixes depends on:– Unit costs of mixtures– Performance during and after placement
Office of Pavem
ent Techno
logy
Office of Pavem
ent Techno
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U.S. Department of TransportationFederal Highway Administration
RAP StateRAP State--ofof--thethe--PracticePractice
The Current Status of Pavement Recycling with RAP
16U.S. Department of TransportationFederal Highway Administration
The The ““StateState--ofof--RecyclingRecycling””
• Survey conducted between June 2007 to March 2008 by Cecil Jones, NCDOT
• Questions posed:– How much RAP is allowed in mixtures?– How much RAP is actually used?– What are the main roadblocks to greater usage of
RAP?
• Responses from all 50 states and Ontario
17U.S. Department of TransportationFederal Highway Administration
Average Amount of RAP Average Amount of RAP -- BaseBase
Permitted by Specifications
0%1 - 10%10 - 20%20 - 30%≥30%n/a
Used
0%10%15%20%25%≥30%n/a
Jones, Cecil. “Review of DOT RAP survey.” Presented to the RAP ETG Meeting, San Diego, CA, March 2008.
18U.S. Department of TransportationFederal Highway Administration
Average Amount of RAP Average Amount of RAP -- IntermediateIntermediate
0%10%15%20%25%≥30%n/a
0%1 - 10%10 - 20%20 - 30%≥30%n/a
Jones, Cecil. “Review of DOT RAP survey.” Presented to the RAP ETG Meeting, San Diego, CA, March 2008.
Permitted by Specifications
Used
19U.S. Department of TransportationFederal Highway Administration
Average Amount of RAP Average Amount of RAP -- SurfaceSurface
0%10%15%20%25%≥30%n/a
0%1 - 10%10 - 20%20 - 30%≥30%n/a
Jones, Cecil. “Review of DOT RAP survey.” Presented to the RAP ETG Meeting, San Diego, CA, March 2008.
Permitted by Specifications
Used
20U.S. Department of TransportationFederal Highway Administration
Amount of RAP Amount of RAP PermittedPermitted (by layer)(by layer)
0 5 10 15 20 25
0
10
15
20
25
≥ 30
n/a
% R
AP
Spec
ified
Number of States
Surface layerIntermediate layerBase layer
21U.S. Department of TransportationFederal Highway Administration
Amount of RAP Amount of RAP UsedUsed (by layer)(by layer)
0 5 10 15 20 25 30 35
0
1-10
10-19
20-29
≥ 30
n/a%
RA
P U
sed
Number of States
Surface layerIntermediate layerBase layer
22U.S. Department of TransportationFederal Highway Administration
State Survey Results SummaryState Survey Results Summary
• Majority of States use between 10 & 20 % RAP in all layers – average ~ 12%.
• Two States (NV & AZ) do not allow RAP and one State does not use RAP (ND).
• Four additional States do not allow RAP in surface mixtures– RI, FL, OK, NM
23U.S. Department of TransportationFederal Highway Administration
Leaders in highLeaders in high--RAP Usage (RAP Usage (≥≥30%*)30%*)
• Base– Montana– South Dakota– Michigan– Ohio– California– Massachusetts– Nebraska
• Surface (20 to 30 %)– Minnesota– Oregon
• Intermediate– Montana– South Dakota– Michigan– Ohio
*Note “by percentage”
24U.S. Department of TransportationFederal Highway Administration
Major Concerns/BarriersMajor Concerns/Barriers
• Consistency/Quality of final mixture properties
• Uniformity of RAP material• Selecting binder grade
– Adequate and uniformly blended total asphalt binder
• Proper mix design procedures• Pavement performance
– Cracking– Durability
FHWA Division Office Survey 2007
25U.S. Department of TransportationFederal Highway Administration
Other major barriersOther major barriers
• Aged binder • Method to measure
asphalt content in RAP• Moisture• Enforcement of
specifications• Restrict RAP when PMA
is used?• Dust-to-binder
requirements• Ninitial requirements
• Premature distress in surface course
• Fatigue• Handling mixture
problems on RAP projects
• Lack of knowledge by end users
FHWA Division Office Survey 2007
26U.S. Department of TransportationFederal Highway Administration
Contractor SurveyContractor Survey
Surface Binder Base Shoulder Polymer-modified SMA
Average Used
Average Allowed by SpecificationsAverage Potential
26
3336 36
20
11
18
2327
26
12
3
12
1821
20
6
1
0
5
10
15
20
25
30
35
40
Perc
ent (
%) R
AP
Pavement Layer or Type
Office of Pavem
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Office of Pavem
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U.S. Department of TransportationFederal Highway Administration
FHWA Involvement and ActivitiesFHWA Involvement and Activities
A National Perspective
28U.S. Department of TransportationFederal Highway Administration
Our ObjectivesOur Objectives
• Encourage the use of recycled materials in the construction of highways to the maximum economical and practical extent possible with equal or improved performance.
• Greatest impact in pavement recycling can be realized through the promotion of Reclaimed Asphalt Pavement (RAP).
29U.S. Department of TransportationFederal Highway Administration
WhatWhat’’s Needed?s Needed?
1. Clear engineering and environmental standards and policy for the use of RAP.
2. Funded, coordinated research to support standards.
3. Public and industry working groups.4. Education.
30U.S. Department of TransportationFederal Highway Administration
FHWA Recycled Materials PolicyFHWA Recycled Materials Policy
• FHWA recognizes need to increase the highway industry’s overall use of recycled materials
• Engineering, Economic, and Environmental benefits
• First consideration in materials selection
• Initial review of engineering and environmental suitability
• Assessment of economic benefits should follow selection process
• Remove restrictions with no technical base
31U.S. Department of TransportationFederal Highway Administration
Guidance DocumentsGuidance Documents
www.fhwa.dot.govwww.fhwa.dot.gov/pavement/recycling/rap/pavement/recycling/rap
32U.S. Department of TransportationFederal Highway Administration
Nationally Funded ResearchNationally Funded Research
• NCHRP Project 9-46– Mix Design and Evaluation Procedure
for High Reclaimed Asphalt Pavement Content in Hot Mix Asphalt
• Asphalt Research Consortium (ARC)– FHWA Cooperative Agreement
33U.S. Department of TransportationFederal Highway Administration
RAP Expert Task Group (ETG)RAP Expert Task Group (ETG)
• FHWA Sponsored
• Membership– State DOT– AASHTO– NCAT– NAPA– Hot Mix Asphalt Industry– North Central
Superpave Center– Academia
• Chairman– Gerry Huber, Heritage
Research Group
• Secretary– Andrea Kvaznak, NCAT
34U.S. Department of TransportationFederal Highway Administration
RAP ETG ActivitiesRAP ETG Activities
• Purpose – 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.
• Showcase Performance - Field Projects • State of Practice and Best Practices • Proposed Standard Practice for Use of RAP
35U.S. Department of TransportationFederal Highway Administration
Field Project GoalsField Project Goals
• Documentation• Mix design process, production, and
construction• Performance testing• Develop information for future mix design
and quality control procedures
• Evaluate potential impact on performance
36U.S. Department of TransportationFederal Highway Administration
Data CollectionData Collection
1) Project Summary
2) Material Properties
3) Production Information
4) LaydownInformation
5) Testing
37U.S. Department of TransportationFederal Highway Administration
Field Projects to DateField Projects to Date
December 200745%Florida
May 200830 – 40 %Kansas
Summer 200830%Delaware
November 200725%Wisconsin
October 200730% and 50%South Carolina
September 200740%North Carolina
DateRAP PercentageState
38U.S. Department of TransportationFederal Highway Administration
Best Practices LearnedBest Practices Learned
• Separate/blended stockpiles• Fractionation• Sample RAP sources
regularly• Plant processing• Warm-mix technologies may facilitate high
RAP • Avoid production of mixtures at various
temperatures - warm mix versus hot mix
Office of Pavem
ent Techno
logy
Office of Pavem
ent Techno
logy
U.S. Department of TransportationFederal Highway Administration
ConstructabilityConstructability
“Farming looks mighty easy when your plow is a pencil and you’re a thousand miles from
the corn field”– Dwight Eisenhower
September 11, 1956
40U.S. Department of TransportationFederal Highway Administration
Constructability ObjectivesConstructability Objectives
• Quality
• Efficiency
• Productivity
• Cost effectiveness
41U.S. Department of TransportationFederal Highway Administration
Using RAP and ConstructabilityUsing RAP and Constructability
The question we’re posing…• How much RAP can we include in the
mix and meet specification and constructability requirements?
• Biggest impact can be made in processing and production.
42U.S. Department of TransportationFederal Highway Administration
Getting the RAP readyGetting the RAP ready……
• Unprocessed RAP– Not subject to QC– Visual Inspection
• Processing RAP– Uniform size– Promotes final blend
consistency
43U.S. Department of TransportationFederal Highway Administration
• Stockpiling– Conical– Well-maintained– Sample frequently
• Comprehensive QC testing– Absorption– Moisture content– Asphalt content– Gradation
Maintaining RAP QualityMaintaining RAP Quality
44U.S. Department of TransportationFederal Highway Administration
• Loader operator
• RAP feed system– Scalping screen
Efficient OperationsEfficient Operations
45U.S. Department of TransportationFederal Highway Administration
At the PlantAt the Plant• Superheating of
aggregate• Air flow• Baghouse• Warm mix
46U.S. Department of TransportationFederal Highway Administration
Insuring QualityInsuring Quality
• Final mixture– Volumetric properties– Extraction– Gradation– Asphalt content– High-RAP
• PG grade of blended binder• Quality of Aggregate
• Performance Testing
47U.S. Department of TransportationFederal Highway Administration
LaydownLaydown and Compactionand Compaction
– No special requirement/techniques
• May require more attention than conventional mixes
– Mix Workability - Stiffer• Density• Heat mixture, more roller
passes, heavier roller?
– Cooler temperatures• Reduced compaction times• Warm mix technologies can
extend compaction times
48U.S. Department of TransportationFederal Highway Administration
SummarySummary
• Asphalt Pavement Recycling– Greatest single upfront cost saving measure
available to highway agencies is increasing the use of RAP in the construction and rehabilitation of asphalt pavements.
– The FHWA encourages the increased use of RAP.
• The majority of State DOTs use between 10 and 20% RAP.
• Contractors can effectively use RAP often and in high amounts with processing and production best practices.
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