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RReclaimed eclaimed AAsphalt sphalt PPavement in avement in Arizona - Application and Arizona - Application and VerificationVerification

October 3, 2008

Arizona Association of County Engineers

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Outline

IntroductionProject OverviewExisting Pavement ConditionConstruction and Production OperationsGranite/ADOT Test ResultsSummary

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Outline

IntroductionProject OverviewExisting Pavement ConditionConstruction and Production OperationsGranite/ADOT Test ResultsSummary

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Change in DOT’s

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Price escalation for construction/rehabilitation and maintenance

Asphalt binder shortages Polymer shortages Environmental concerns Energy concerns Funding limitations

Changing Market Conditions = Renewed Interest in Recycling

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States Allowance of RAP

75-percent of States allow at least 10-percent RAP in surface course mixes

More States allow higher percentages in lower lifts

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15% RAP in HMA 25% RAP in HMA

Energy, BTU 5 8

AC Consumed, tons 12 19

Aggregate Consumed, tons 6 10

CO2 (lb) 7 12

CO (lb) 8 13

NOx (lb) 5 9

SOx (lb) 9 16

PM-10 (lb) 6 10

Value of Recycling – Percent Savings Relative to Conventional Materials – Initial

Construction*

*equivalent square yardsNote: Similar advantages found with Life Cycle Cost

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PCI Over Time*

*Projects constructed in Arizona

0

10

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30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10

Time (Years)

PC

I

Conventional HMA

Recycled HMA

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Outline

IntroductionProject OverviewExisting Pavement ConditionConstruction and Production OperationsGranite/ADOT Test ResultsSummary

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Project Layout

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Standard Sections

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Scope of Work Partial depth removal of existing asphalt concrete Placement of dense grade asphalt concrete Placement of AR-ACFC Miscellaneous other work Granite’s Proposal

Use RAP in base course HMA6% coarse RAP (3/4-in x 3/8-in)9% fine RAP (3/8-in minus)

Note: RAP currently used as shoulder backing and aggregate base on ADOT projects

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Standard Section

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Outline

IntroductionProject OverviewExisting Pavement ConditionConstruction and Production OperationsGranite/ADOT Test ResultsSummary

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Alligator Cracking

Moderate severity alligator cracking Existing pavement prior to rehabilitation

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Transverse Cracking

Slight to moderate severity transverse cracking Existing pavement prior to rehabilitation

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Block Cracking

Block cracking

Existing pavement prior to rehabilitation

Maybe considered combination of longitudinal and transverse cracking

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Outline

IntroductionProject OverviewExisting Pavement ConditionConstruction and Production OperationsGranite/ADOT Test ResultsSummary

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Cold Milling Operations

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Unprocessed RAP from I-19

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Coarse RAP (3/4-in x 3/8-in)

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Fine RAP (3/8-in Minus)

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Hot Plant Feeders5 Virgin Aggregate Bins

2 RAP Bins

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Hot PlantCement Silo and Pugmill

Virgin Aggregate Scalping Screen

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Hot Plant

Counter Flow Drum Mixer

RAP Conveyor

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Paving and InspectionHMA Paving

Density Testing

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Rolling OperationsEchelon Breakdown Rolling

Finish Rolling

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Finished Mat

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Outline

IntroductionProject OverviewExisting Pavement ConditionConstruction and Production OperationsGranite/ADOT Test ResultsSummary

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Granite Test Results – RAP*

Testing Lab

RAP Source

Stat3/8-in

Sieve, % Passing

No. 8 Sieve, % Passing

No. 40 Sieve, % Passing

No. 200, % Passing

Asphalt Binder

Content, %DWA

Granite - Arizona

CoarseNo. 10 10 10 10 10

Std. Dev.** 3.5 2.0 1.1 0.38 0.53

FineNo. 11 11 11 11 11

Std. Dev. 0.0 1.9 1.6 1.17 1.09

Granley Std. Dev. 2.81 0.94 0.28

Rep. Range Std. Dev. 2.0 – 4.5 2.0 – 3.5 0.5 – 1.5 0.15 – 0.45

Rep. Value Std. Dev. 3.30 2.80 0.90 0.30

*Test results based on ignition oven**Standard Deviation – measure of variability

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Granite Test Results – RAP*

Testing Lab

RAP Source

Stat3/8-in

Sieve, % Passing

No. 8 Sieve, % Passing

No. 40 Sieve, % Passing

No. 200, % Passing

Asphalt Binder

Content, %DWA

Granite - Arizona

CoarseNo. 5 5 5 5 5

Std. Dev.** 5.3 3.2 1.5 0.60 0.42

FineNo. 7 7 7 7 7

Std. Dev. 0.0 1.9 1.1 0.70 0.22

Granley Std. Dev. 2.81 0.94 0.28

Rep. Range Std. Dev. 2.0 – 4.5 2.0 – 3.5 0.5 – 1.5 0.15 – 0.45

Rep. Value Std. Dev. 3.30 2.80 0.90 0.30

*Test results based on solvent extraction**Standard Deviation – measure of variability

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Granite/ADOT Test Results - Gradation

*Standard Deviation – measure of variability

Gradation of aggregate extracted from field mixed samples

Standard Deviation of Percent Passing Sieve, %

3/8-in No. 8 No. 40 No. 200

Granite 2.95 2.56 1.18 0.57

ADOT 3.22 2.14 0.88 0.46

Granite & ADOT 3.10 2.35 1.04 0.51

Granley 2.81 0.94

NCHRP 455

Rep. Range 2.0 – 4.5 2.0 – 3.5 0.5 – 1.5

Rep. Value 3.3 2.8 0.9

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Granite/ADOT Test Results - Volumetrics

*Standard Deviation – measure of variability

Volumetric properties of field mixed/lab compacted samples

Bulk Density,

lb/ft3

Rice Density,

lb/ft3

Air Voids, %

Asphalt Binder

Content, %

Granite 0.95 0.58 0.81 0.29

ADOT 0.80 0.49 0.67 0.21

Granite & ADOT 0.88 0.53 0.74 0.25

Granley 0.28

NCHRP 455

Rep. Range 0.3 – 1.2 0.15 – 0.45

Rep. Value 0.7 0.3

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Outline

IntroductionProject OverviewExisting Pavement ConditionConstruction and Production OperationsGranite/ADOT Test ResultsSummary

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Recycling Benefits

Conservation Materials (aggregate and asphalt binder)

Energy (burner fuel, trucking, etc.)

Preservation of environment Landfill

Green house gases (global warming)

Sustainability

Economics Reduce first and life cycle cost

Complete reconstruction vs. alternative methods

Increased contractor competition

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Questions