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Emissions and Energy in the Asphalt Paving Industry

Chris Robinette

January 18, 2010

National Asphalt

Pavement Association

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?Question?

What are the considerations for HMA carbon

footprint?

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Life Cycle Assessment

Crude oil extraction and refiningAggregate extraction and processingTransportation of raw materialsPlant productionTransportation of finished productPlacement

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?Question?

Why is our carbon

footprint important?

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Environmental Awareness

“US to Regulate Greenhouse Gas Emiss ions”

“EPA Says Greenhouse Gases Endanger Human Heal th”

“Governor, Legis la tors Unvei l P lan to Reduce Greenhouse Gases”

“Uni ted Nat ions Framework Convent ion on Cl imate Change”

“Obama Vows Greenhouse Gas Emiss ion Cuts”

“Obama to go to Copenhagen wi th Emiss ions Target”

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?Question?

How is HMA carbon footprint

information being used?

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Instances of Use

Sacramento Municipal Utility District (SMUD)Residential customer purchase of carbon offset

Promotion of alternative technologiesWarm mix asphalt for Sacramento Regional

Transit AuthorityRAP in HMA for various agenciesHot in-place recycling on SR 542 (Washington)

Promotion of Green activitiesMarvin M Black Award - AGC

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Information Sources

NCHRP 214

Colas Group

PaLATE Athena Contractor Data

1980 2003 2003 2006 2009

Energy Consumption, Btu

X X X X X

Emissions Generation, CO2eq

X X X X

Conservation of Resources, ton

X

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Upstream – To Produce One Ton of Material*

Asphalt Binder600,000 to 4,200,000-Btu280 to 675-lb CO2eq

Aggregate15,000 to 52,000-Btu3 to 20-lb CO2eq

*Values based on multiple references

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Haul distanceMethod of transportation

Truck – 155-ton-miles/gallon – 25-tons/truckRail – 436-ton-miles/gallon – 143-tons/carBarge – 576-ton-miles/gallon – 1,500-tons/boat

Type of fuel consumedDiesel

~139,000-Btu/gallon ~22.6-lbs CO2eq/gallon

Gasoline~124,000-Btu/gallon ~20.0-lbs CO2eq/gallon

Transportation of Raw Materials and Finished Product

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Plant CO2 Emissions, lb/ton

*Based on EPA AP-42 Emission Factors for a drum mix hot plant

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Equipment compositionType of equipment enginesProductivityFuel used

Placement

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?Question?

What is the benefit to

using RAP?

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RAP in HMA – Emissions & Energy Analysis*

Material / Process Recycled Material

Content, %

Recycled Asphalt Binder

Content, %

Emissions, Approx.

CO2eq/ton

Energy, Approx. Btu/ton

Conventional HMA 0 0 104.89 533,333

RAP

15 4 98.59 501,778

15 5 97.76 495,544

25 4 94.39 480,741

25 5 93.01 470,352

*percent savings in comparison to conventional alternative

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RAP in HMA – Natural Resource Analysis*

Material / Process Recycled Material

Content, %

Recycled Asphalt Binder

Content, %

Asphalt, ton/ton

Agg, ton/ton

Conventional HMA 0 0 - -

RAP

15 4 11.5 15.1

15 5 14.4 15.0

25 4 19.2 25.3

25 5 24.0 25.1

*percent savings in comparison to conventional alternative

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?Question?

What about warm mix and

asphalt shingles?

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Shingles & WMA – Emissions & Energy Analysis*

Material / Process Recycled Material

Content, %

Recycled Asphalt Binder

Content, %

Emissions, Approx.

CO2eq/ton

Energy, Approx. Btu/ton

Conventional HMA 0 0 104.89 533,333

Post Industrial Asphalt Shingles**

5.0 18.0 98.94 493,724

5.0 23.0 97.29 481,256

Post Consumer Asphalt Shingles**

5.0 32.0 95.09 464,633

5.0 40.0 92.89 448,009

Warm Mix Asphalt - - 102.90 510,977

*percent savings in comparison to conventional alternative**Effective contribution of asphalt binder from asphalt shingles will influence savings

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Shingles & WMA – Natural Resource Analysis*

Material / Process Recycled Material

Content, %

Recycled Asphalt Binder

Content, %

Asphalt, ton/ton

Agg, ton/ton

Conventional HMA 0 0 - -

Post Industrial Asphalt Shingles**

5.0 18.0 17.3 4.3

5.0 23.0 23.1 4.0

Post Consumer Asphalt Shingles**

5.0 32.0 30.8 3.6

5.0 40.0 38.5 3.2

Warm Mix Asphalt - - 0.0 0.0

*percent savings in comparison to conventional alternative**Effective contribution of asphalt binder from asphalt shingles will influence savings

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?Question?

Are there other considerations?

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Life Cycle Assessment Format

Reconstruction

M&F M&F M&F

CS

CS

CS CS

Salvage

IC

0 7 11 14 19 23 28 32 37 40

IC = Initial Cost CS = Crack Seal M&F = Mill & Fill

CS

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Expected Service Life

Representative Range

Representative Value

HMA 12 – 18 14

Fog Seal 1 – 3 2

Crack Sealing 2 – 5 4

Slurry Seal 3 – 7 5

Chip Seal 3 – 10 6

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Life Cycle Assessment

Similar approach to previously presentedConsiderations

Estimated lifePrice of rehabilitation/maintenanceDiscount rateAnalysis periodSalvage value – end of life

Additional savings seen in LCA

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?Question?

Are there other opportunities?

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OperationsRepresentative (Rep.) Range

Rep. Value (Value Used in

Analysis)

Cold Milling Asphalt Pavement 0.080 - 3.500 1.730 Hot Mix Asphalt 5.600 – 5.900 5.900 CIPR - Partial Depth 0.711 CIPR - Full Depth 0.900 – 4.100 1.354 HIPR – Remixing 2.341 Conventional Aggregate Base 1.400 – 1.600 1.553 Recycled Aggregate Base 1.436 Emulsion Stabilized Aggregate Base 2.457 Cement Stabilized Aggregate Base 4.200 - 5.200 4.700 Cement Treated Subgrade 1.868 Lime Treated Subgrade 1.421

Construction and Rehabilitation, CO 2eq /yd 2 -in

Operation Estimated Emissions Generation, lbs CO2eq/yd2-in

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OperationsRepresentative (Rep.) Range

Rep. Value (Value Used in Analysis)

Cold Milling Asphalt Pavement 1,000 – 2,500 1,800 Hot Mix Asphalt 27,000 – 34,000 30,000 CIPR - Partial Depth 3,000 – 24,000 12,000 CIPR - Full Depth 1,300 – 15,000 3,900 HIPR – Remixing 9,000 – 27,000 16,000 Conventional Aggregate Base 5,000 – 12,000 10,000 Recycled Aggregate Base 4,000 - 8,000 7,800 Emulsion Stabilized Aggregate Base 9,000 – 33,000 9,600 Cement Stabilized Aggregate Base 13,000 - 15,000 14,000  Cement Treated Subgrade 7,900  Lime Treated Subgrade 3,000 – 7,000 5,100 

Construction and Rehabilitation, Btu/yd 2 -in

Operation Estimated Energy Consumption, Btu/yd2-in

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Material Stabilization

AASHTO 93’ Design GuideRepresentative layer coefficients

Untreated aggregate base – 0.14Recycled aggregate base – 0.16Emulsion stabilized aggregate base – 0.22Cement stabilized aggregate base – 0.22Cement stabilized subgrade – 0.16Lime stabilized subgrade – 0.15

Design equivalent pavement structuresLow volume facility

~1,000,000-ESALs

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HMA5.0-in

Conv. AB

11.0-in

Subgrade

Rec. AB9.5-in

Subgrade

Emul. Stab AB

7.0-in

Subgrade

Cement Stab

Subgrade9.5-in

Subgrade

Lime Stab

Subgrade10.0-in

Subgrade

Cement Stab AB

7.0-in

Subgrade

HMA5.0-in

HMA5.0-in

HMA5.0-in

HMA5.0-in

HMA5.0-in

Stabilization – Environmental Analysis

Energy, % Savings (measured in Btu/yd2)

- 12.3 5.5 -7.9 2.1 12.6

Emissions, % Savings (measured in CO2eq/yd2)

- 6.8 -0.2 -33.9 1.8 6.2

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HMA5.0-in

Conv. AB

11.0-in

Subgrade

Rec. AB9.5-in

Subgrade

Emul. Stab AB

7.0-in

Subgrade

Cement Stab

Subgrade9.5-in

Subgrade

Lime Stab

Subgrade10.0-in

Subgrade

Cement Stab AB

7.0-in

Subgrade

HMA5.0-in

HMA5.0-in

HMA5.0-in

HMA5.0-in

HMA5.0-in

Stabilization – Natural Resource Analysis

Asphalt Binder, % Savings (measured in ton/yd2)

- 0.0 -52.8 0.0 0.0 0.0

Aggregate, % Savings (measured in ton/yd2)

- 9.3 25.8 24.9 68.4 68.4

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Summary

Emissions is dependent upon fuel sourceBenefits of RAP are up stream of the hot

plantWarm mix asphalt reduces greenhouse

gas emissions and energy consumptionThere are other opportunities to be GreenWhy is this information important?

Painting the construction industry Green

?Question?

What does

2,800 represent?

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What Produces More CO2?

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vs

US Cattle (Beef & Dairy)

104,000,000-head of cattle in US (2007)

145,615,000-tons of CO2eq emitted annually

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University of Missouri - Columbia &US EPA

Tale of the Tape

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vs

145,615,000-tons CO2eq/year 28,875,000-tons CO2eq/yearAssumes no RAP

Difference of 116,740,000-tons CO2eq/year

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What Can We Do to Reduce Global Warming?

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Questions