Greening the BlacktopGreening the Blacktop

Going Green with Going Green with Sustainable AsphaltSustainable AsphaltRAP, Recycling, Energy and RAP, Recycling, Energy and

the Carbon Footprintthe Carbon Footprint

OverviewOverview Why Asphalt is sustainableWhy Asphalt is sustainable

Perpetual PavementsPerpetual Pavements Carbon FootprintCarbon Footprint RAP & Recycling RAP & Recycling Warm Mix AsphaltWarm Mix Asphalt Porous AsphaltPorous Asphalt Energy & Emission ReductionsEnergy & Emission Reductions

WhyWhyAsphalt is Asphalt is

SustainableSustainable

Sustainable Sustainable PavementsPavements

Sustainable PavementSustainable PavementDurability…Durability…

Asphalt is the Perpetual PavementAsphalt is the Perpetual Pavement

Road itself doesn’t wear outRoad itself doesn’t wear outSimple, fast maintenanceSimple, fast maintenanceReclaimed…is then reusedReclaimed…is then reusedTotal removal/reconstruction not Total removal/reconstruction not

neededneeded

Sustainable PavementSustainable PavementRequires less energy to construct an Requires less energy to construct an

asphalt pavementasphalt pavementPer ASCE…20% lessPer ASCE…20% lessLess energy consumed by publicLess energy consumed by publicLess maintenance keeps traffic movingLess maintenance keeps traffic moving

Max Tensile Strain

Pavement FoundationPavement Foundation

High ModulusRut Resistant Material(Varies As Needed)

Flexible Fatigue ResistantMaterial 75 - 100 mm

}100 mmto150 mm

ZoneOf High

Compression

Perpetual PavementsPerpetual Pavements40-75 mm STONE MATRIX ASPHALT, OGFC or Superpave

{

RehabilitationRehabilitation

50 - 100 mm

Str

uctu

re R

em

ain

s I

nta

ct

Possible DistressesPossible Distresses› Top-Down FatigueTop-Down Fatigue

› Thermal CrackingThermal Cracking

› RavelingRaveling

SolutionsSolutions› Mill & FillMill & Fill

› Thin OverlayThin Overlay

Mill Surface – Use for RAPHigh Quality Stone Matrix, OGFC or Superpave

20+ YearsLater

Carbon Carbon FootprintFootprint

What the heck is a What the heck is a Carbon Footprint?Carbon Footprint?

A carbon footprintA carbon footprint is defined as:is defined as:

The total amount of greenhouse The total amount of greenhouse gases produced to directly and gases produced to directly and

indirectly support human activities, indirectly support human activities, usually expressed in equivalent usually expressed in equivalent

tons of (CO2)tons of (CO2)

Doesn’t segregate GHGsDoesn’t segregate GHGs

Environmental SustainabilityEnvironmental Sustainability

Climate RegistriesClimate RegistriesOrganizations that collect and Organizations that collect and

compile emissions data generally compile emissions data generally voluntary (CA, NE US)voluntary (CA, NE US)

Encourages voluntary early Encourages voluntary early actions to increase energy actions to increase energy efficiency and decrease GHG efficiency and decrease GHG emissionsemissions

What is a Greenhouse Gas?What is a Greenhouse Gas?

Gases that trap heat in the Gases that trap heat in the atmosphere – Allows us to atmosphere – Allows us to live herelive here

Some occur from nature, Some occur from nature, others from anthropogenic others from anthropogenic activitiesactivities

What is a Greenhouse Gas?What is a Greenhouse Gas?

Principal greenhouse gases Principal greenhouse gases entering the atmosphere from entering the atmosphere from human activities are:human activities are:

Carbon dioxide (CO2)Carbon dioxide (CO2)Methane (CH4)Methane (CH4)Nitrous Oxides (N2O)Nitrous Oxides (N2O)Fluorinated gases (HFCs & PFCs)Fluorinated gases (HFCs & PFCs)

Regulatory ConcernsRegulatory Concerns

Efforts to make you report emissionsEfforts to make you report emissions Benefits of being ahead of the waveBenefits of being ahead of the wave Demonstrates concern for the public Demonstrates concern for the public

and the environmentand the environment

Opportunities to Reduce Opportunities to Reduce EmissionsEmissions

Sustainable PavementsSustainable Pavements Warm MixWarm Mix RAPRAP Plant O & MPlant O & M Truck and other equipment Truck and other equipment

maintenancemaintenance

RAP &RAP &RecyclingRecycling

RecyclabilityRecyclability Asphalt is the No. 1 recycled materialAsphalt is the No. 1 recycled material Biggest Re-userBiggest Re-user 1995 FHWA Report to congress1995 FHWA Report to congress

90 Million tons reclaimed90 Million tons reclaimed80% recycled80% recycled

2006 Contractor Survey2006 Contractor Survey~69% reused in HMA~69% reused in HMA~27% other recycling~27% other recycling<3% discarded<3% discarded

Why Recycle RAP into HMA?Why Recycle RAP into HMA?Best and Highest useBest and Highest useReduces demand for new materialsReduces demand for new materialsReduces carbon footprintReduces carbon footprintContains valuable materialsContains valuable materials

Aggregate ~95% >$10/tonAggregate ~95% >$10/tonAsphalt ~5% > $400/tonAsphalt ~5% > $400/tonValue >$29.50/ton (minus processing)Value >$29.50/ton (minus processing)

ShinglesShinglesShinglesShinglesMaterials used in HMAMaterials used in HMA

>20% asphalt binder>20% asphalt binderFibersFibersSandSand

Usually 5% of mixUsually 5% of mixSaves 1% binder >Saves 1% binder >

$6.00/ ton of HMA/WMA $6.00/ ton of HMA/WMATear-offsTear-offs

Over the past two years, MoDOT has allowed contractors to put used shingles that have been removed from rooftops into their asphalt mix. The result is a very durable, more-rut resistant asphalt at a much lower price.

The use of recycled shingles saves $3 to $5 per ton of asphalt. That may not sound like much at first, but consider this: a typical resurfacing project would use about 30,000 tons of asphalt, for a savings of $90,000 to $150,000.

Other Recycled MaterialsOther Recycled MaterialsCrumb rubber Crumb rubber

(from tires)(from tires)

Steel slagSteel slag

GlassGlass

Warm Mix Classifications

0123456789

0 100 200 300 400

T emperature, °F

Lit

ers

Fu

el/T

on

C old Mix

Half-Warm

WMA

HMA

Lower Temperature AdvantagesLower Temperature Advantages

Lower energy consumption (≈30%)Lower energy consumption (≈30%) Lower plant wearLower plant wear Decreased binder agingDecreased binder aging Early site opening – Return to userEarly site opening – Return to user Cool weather pavingCool weather paving Compaction aid for stiff mixesCompaction aid for stiff mixes Cooler working conditionsCooler working conditions

Porous Porous AsphaltAsphalt

What are Porous Pavements?What are Porous Pavements?

Open-Graded HMA/WMA ~ 2 ½”

½” Agg. (#57) ~ 1” – 2” Thick

Clean Uniformly Graded 2”-3”Crushed Agg. (#2) – 40% Voids

Non-Woven Geotextile

Uncompacted Subgrade

Porous PavementPorous PavementStormwater quality improved Stormwater quality improved

with:with: Porous pavement, andPorous pavement, and Open Grade Friction CourseOpen Grade Friction Course

Can eliminate the need for Can eliminate the need for stormwater structuresstormwater structures

Water QualityWater Quality

Walden Pond 1977Walden Pond 19771997 Report: “Twenty years later, a long time for one paving job on that busy parking lot, it still looks good and works well.”

2008

Energy & Energy & Emission Emission

ReductionsReductions

Warm MixWarm MixWill dominate the market in < 5 yearsWill dominate the market in < 5 yearsReduced energy consumptionReduced energy consumptionReduced emissionsReduced emissions

No hazardous fumes/worker exposureNo hazardous fumes/worker exposure Plants compatible in congested areasPlants compatible in congested areasNo odorsNo odors

The sooner the better!The sooner the better!

Remedial EffortsRemedial EffortsUse the components of the carbon Use the components of the carbon

footprint to identify problem areasfootprint to identify problem areasTake action and make adjustments to Take action and make adjustments to

reduce emissionsreduce emissionsSwitch to Warm Mix soonerSwitch to Warm Mix soonerConduct energy auditsConduct energy auditsTake action to reduce energyTake action to reduce energy

Energy Use by Road Material TypeEnergy Use by Road Material Type

126 142 149178 182 189

205

341

0

50

100

150

200

250

300

350

400

HMA 50%RAP

HMA 30%RAP

HMA 20%RAP

HMA 10%RAP

Warm Mix Hot-Mix ConcretePavement

ReinforcedConcretePavement

kW*h

/ton

Colas Group DataColas Group Data

Reduced Energy ConsumptionReduced Energy Consumption

Energy AuditsEnergy AuditsDOE SoftwareDOE SoftwareUse RAPUse RAPWarm Mix Can Reduce Energy byWarm Mix Can Reduce Energy by

Cover the AggregateCover the Aggregate

⅓

Why is Asphalt SustainableWhy is Asphalt Sustainable

100% Recyclable100% RecyclableCan use other recycled materialsCan use other recycled materialsLow carbon footprint pavementLow carbon footprint pavementLong life & fast resurfacingLong life & fast resurfacingWarm-Mix AsphaltWarm-Mix AsphaltPorous pavement for stormwaterPorous pavement for stormwater

NAPA ThemeNAPA Theme

RAP + PorousRAP + Porous+ Warm Mix + Perpetual + Warm Mix + Perpetual

Pavements =Pavements =

SustainabilitySustainability

Summary & ReviewSummary & Review Why Asphalt is sustainableWhy Asphalt is sustainable

Perpetual PavementsPerpetual Pavements Carbon FootprintCarbon Footprint RAP & Recycling RAP & Recycling Warm Mix AsphaltWarm Mix Asphalt Porous AsphaltPorous Asphalt Energy & Emission ReductionsEnergy & Emission Reductions

Questions?Questions?