This document discusses designing mixes with high percentages of reclaimed asphalt pavement (RAP). It notes current allowances for RAP by various agencies, ranging from 15% up to 50%. Reasons for recycling include landfill shortages and beneficial use of the material. Blending charts are commonly used but may not fully account for how RAP binder blends with virgin binder. The steps in developing a mix design with high RAP include selecting materials, designing the aggregate structure, determining the asphalt binder content, and verifying the mix design meets specifications. Extensive quality control and assurance testing is also required.

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DESIGNING MIXES WITHDESIGNING MIXES WITH
HIGH RAP % IN HMAHIGH RAP % IN HMA
CALAPA FALL CONFERENCE
SACRAMENTO
OCTOBER 25, 2018

2. 22
CURRENT % RAP ALLOWEDCURRENT % RAP ALLOWED
 Caltrans – HMA – up to 15%Caltrans – HMA – up to 15%
– Superpave – 25% +/-1Superpave – 25% +/-1
 Green Book – Section 203-6 – up to 15%Green Book – Section 203-6 – up to 15%
 Section 203-7 – >15%Section 203-7 – >15%
 City of LA Contract – 50% RAPCity of LA Contract – 50% RAP
 High RAP is considered to be over 15% to 20% RAPHigh RAP is considered to be over 15% to 20% RAP

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WHY RECYCLE?WHY RECYCLE?
 –– Landfill shortage.Landfill shortage.
 August 11,1987 City order prohibitingAugust 11,1987 City order prohibiting
the landfilling of road materials.the landfilling of road materials.
 Beneficial UseBeneficial Use
 Excellent performanceExcellent performance

4. 44

5. USING BLENDING CHARTSUSING BLENDING CHARTS
 RAP does not behave like black rockRAP does not behave like black rock
 RAP binder does not completely blendRAP binder does not completely blend
completely with virgin bindercompletely with virgin binder
 Somewhere in betweenSomewhere in between
 Blending depends on RAP binderBlending depends on RAP binder
stiffness, mixing temperature, storagestiffness, mixing temperature, storage
temperature and timetemperature and time
 Blending charts presume that completeBlending charts presume that complete
blending occursblending occurs
55

6. EXAMPLE – PROPERTIES OFEXAMPLE – PROPERTIES OF
RECOVERED RAP BINDERRECOVERED RAP BINDER
AGING PROPERTY CRITICAL TEMPERATURE
DSR G*/SIN δ HIGH 86
DSR G*SIN δ INTERMEDIATE 31
RTFO BBR S LOW -14
BBR m-VALUE LOW -11
PG Actual PG 86 -11
M320 PG 82 -10
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7. EXAMPLEEXAMPLE
Agency requires a blended PG 64 -22 orAgency requires a blended PG 64 -22 or
betterbetter
Critical Temperature of the virgin asphaltCritical Temperature of the virgin asphalt
T virgin = T blend –(RPBR x T RAP)T virgin = T blend –(RPBR x T RAP)
(1 –RPBR)(1 –RPBR)
== 64 – (0.30 X 86)64 – (0.30 X 86) = 54.6= 54.6
(1 – 0.30)(1 – 0.30)
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8. EXAMPLEEXAMPLE
Example - Properties of virgin asphalt binder
AGING PROPERTY
CRITICAL
TEMPERATURE
DSR G*/SIN δ HIGH 55
DSR G*SIN δ INTERMEDIATE 22
RTFO BBR S LOW -26
BBR m-VALUE LOW -27
PG Actual PG 55 -27
M320 PG 58 -28
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9. BLENDING ANALYSISBLENDING ANALYSIS
 Three likely cases:Three likely cases:
– What virgin binder grade when RAP binder %What virgin binder grade when RAP binder %
as well as FINAL blended binder grade isas well as FINAL blended binder grade is
known.known.
– What RAP binder % to be used when specificWhat RAP binder % to be used when specific
virgin binder is to be used and FINAL blendedvirgin binder is to be used and FINAL blended
binder grade is known.binder grade is known.
– What FINAL blended binder grade when RAPWhat FINAL blended binder grade when RAP
binder % and virgin binder grade is fixedbinder % and virgin binder grade is fixed
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10. STEPS IN MIX DESIGNSTEPS IN MIX DESIGN
DEVELOPMENTDEVELOPMENT
 SELECTION OF MATERIALSSELECTION OF MATERIALS
 SELECTION OF DESIGN AGGREGATESELECTION OF DESIGN AGGREGATE
STRUCTURE.STRUCTURE.
 ASPHALT BINDER CONTENTASPHALT BINDER CONTENT
 VERIFY MIX DESIGNVERIFY MIX DESIGN
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11. SELECTION OF MATERIALSSELECTION OF MATERIALS
 Evaluate RAPEvaluate RAP
– Determine binder content and maximumDetermine binder content and maximum
theoretical specific gravity.theoretical specific gravity.
– Determine RAP propertiesDetermine RAP properties
– Fractionate if necessaryFractionate if necessary
– Determine RAP consensus properties ifDetermine RAP consensus properties if
desired. CAA, FAA and Flat and Elongateddesired. CAA, FAA and Flat and Elongated
– Estimate RAP aggregate specific gravityEstimate RAP aggregate specific gravity
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12. SELECTION OF MATERIALSSELECTION OF MATERIALS
 Virgin Asphalt BinderVirgin Asphalt Binder
– Project weather conditionsProject weather conditions
– If required decrease high and low temperatureIf required decrease high and low temperature
grad of virgin binder by one increment.grad of virgin binder by one increment.
– Desired PG 64 -10 – use PG 58 -16Desired PG 64 -10 – use PG 58 -16
– Contract documents may specify what binderContract documents may specify what binder
grade to use.grade to use.
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13. SELECTION OF MATERIALSSELECTION OF MATERIALS
 Virgin AggregateVirgin Aggregate
– Measure consensus properties – CAA, FAA,Measure consensus properties – CAA, FAA,
F&E, SEF&E, SE
– Combined GradationCombined Gradation
– Specific gravity or other properties required bySpecific gravity or other properties required by
agencyagency
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14. DESIGN AGGREGATEDESIGN AGGREGATE
STRUCTURESTRUCTURE
 Trial BlendsTrial Blends
– Establish trial asphalt binder contentEstablish trial asphalt binder content
 Superpave methodSuperpave method
 Engineering judgementEngineering judgement
 Adjust for RAP binder contentAdjust for RAP binder content
– Determine trial blend specimen sizeDetermine trial blend specimen size
– Determine NDetermine Ninitialinitial, N, Ndesigndesign and Nand Nmaxmax based on designbased on design
traffic leveltraffic level
– Batch trial blend specimensBatch trial blend specimens
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15. DESIGN AGGREGATEDESIGN AGGREGATE
STRUCTURESTRUCTURE
 Trial BlendsTrial Blends
– Compact gyratory samplesCompact gyratory samples
– Generate densification tablesGenerate densification tables
– Determine mixture propertiesDetermine mixture properties
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16. DESIGN AGGREGATEDESIGN AGGREGATE
STRUCTURESTRUCTURE
 Evaluate Trial BlendsEvaluate Trial Blends
– Determine %GDetermine %Gmmmm @ N@ Ninitialinitial and Nand Ndesigndesign
– Determine % air voids and VMADetermine % air voids and VMA
– Estimate binder content at 4% air voidsEstimate binder content at 4% air voids
– Estimate mixture properties at estimatedEstimate mixture properties at estimated
asphalt binder contentasphalt binder content
– Determine dust-to-asphalt ratioDetermine dust-to-asphalt ratio
 Select most promising design aggregateSelect most promising design aggregate
structure for further testingstructure for further testing
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17. DESIGN ASPHALT BINDERDESIGN ASPHALT BINDER
CONTENTCONTENT
 Compact Design Aggregate StructureCompact Design Aggregate Structure
specimens at multiple binder contents inspecimens at multiple binder contents in
0.5% increments – typically 4 or 5.0.5% increments – typically 4 or 5.
 Adjust for RAP binder.Adjust for RAP binder.
 Compact specimens and generateCompact specimens and generate
densification tablesdensification tables
 Determine Mixture PropertiesDetermine Mixture Properties
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18. DESIGN ASPHALT BINDERDESIGN ASPHALT BINDER
CONTENTCONTENT
– Determine %GDetermine %Gmmmm @ N@ N initialinitial and Nand N designdesign
– Determine volumetricsDetermine volumetrics
– Graph mix properties versus asphalt binderGraph mix properties versus asphalt binder
contentcontent
 Select Design Asphalt Binder ContentSelect Design Asphalt Binder Content
– Determine asphalt binder content at 4% airDetermine asphalt binder content at 4% air
voidsvoids
– Determine mix properties at selected asphaltDetermine mix properties at selected asphalt
binder contentbinder content
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19. DESIGN ASPHALT BINDERDESIGN ASPHALT BINDER
CONTENTCONTENT
 Do you meet specificationsDo you meet specifications
 VERIFY MIX DESIGNVERIFY MIX DESIGN
– Evaluate moisture sensitivity AASHTO T283Evaluate moisture sensitivity AASHTO T283
– Any other tests?Any other tests?
– Confirm that %GConfirm that %Gmmmm is less than 98%is less than 98%
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20. MIX DESIGN EXAMPLEMIX DESIGN EXAMPLE
 Do you meet specificationsDo you meet specifications
 VERIFY MIX DESIGNVERIFY MIX DESIGN
– Evaluate moisture sensitivity AASHTO T283Evaluate moisture sensitivity AASHTO T283
– Any other tests?Any other tests?
– Confirm that %GConfirm that %Gmmmm is less than 98%is less than 98%
2020

21. Recycling Agents (ASTM
D4552)
RA1 RA5 RA25 RA75 RA250 RA500
Viscosity @
60C (cSt) 50-175 176-900901-
4500
4501-
12500
12501-
37500
37501-
60,000
Flash Point, C,
Minimum
218 218 218 218 218 218
Saturates, %,
Minimum
30 30 30 30 30 30
Viscosity Ratio
(RTFO or
TFO)
3 3 3 3 3 3

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TestingTesting
 Extensive QC TestingExtensive QC Testing
– Gradation and AC% on RAPGradation and AC% on RAP
– Gradation on aggregatesGradation on aggregates
– PG 64 -10 and Recycling AgentPG 64 -10 and Recycling Agent
– 75 Blow Marshalls75 Blow Marshalls
 Extensive QA testingExtensive QA testing
– 4 to 8 samples4 to 8 samples
– 75 Blow Marshalls75 Blow Marshalls
– Superpave for ARRA jobsSuperpave for ARRA jobs

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25. 2525
RAP Processing

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StockpilingStockpiling

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Finished ProductFinished Product
½” minus RAP

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Los Angeles RegionalLos Angeles Regional
LabLab
Viscosity Testing
Extraction/Recovery

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QuestionsQuestions
Pascal Mascarenhas
Vulcan Materials
mascarenhasp@vmcmail.com
626-856-6190 Phone
626-969-2918 Fax
626-705-6611 Cell

31. 3131
THANK YOU