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Full Depth Pavement Full Depth Pavement Reclamation Using Coal Reclamation Using Coal Combustion Products in Combustion Products in

Marquette CountryMarquette CountryThomas Jansen, We EnergiesThomas Jansen, We EnergiesThomas Van Dam, Michigan TechThomas Van Dam, Michigan TechAnne Anne PeairsPeairs, Michigan Tech, Michigan Tech

Michigan County Engineers WorkshopMichigan County Engineers WorkshopFebruary 21, 2006February 21, 2006

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Coal Combustion Products (CCP)Coal Combustion Products (CCP)

►► Fly ashFly ash►► Bottom ashBottom ash►► Boiler slagBoiler slag►► Flue gas Flue gas desulfurizationdesulfurization materialmaterial

FGD wet scrubber materialsFGD wet scrubber materialsFGD gypsumFGD gypsumDry scrubber materialsDry scrubber materials

►► Fluidized bed combustion materialsFluidized bed combustion materials►► Integrated Coal Gasification byIntegrated Coal Gasification by--productsproducts

SlagSlagSulfurSulfurSulfuric AcidSulfuric Acid

►► Recovered coal ashRecovered coal ash

Coal ash is Coal ash is calcinedcalcined and melted and melted inorganic soils that are within coalinorganic soils that are within coal

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Fly ash is a pozzolanFly ash is a pozzolan

A pozzolan is primarily a siliceous or siliceous and A pozzolan is primarily a siliceous or siliceous and aluminous material, in a finely divided form and in the aluminous material, in a finely divided form and in the presence of water, chemically reacts with calcium presence of water, chemically reacts with calcium hydroxide (lime) at ordinary temperatures to form hydroxide (lime) at ordinary temperatures to form compounds possessing cementitious properties.compounds possessing cementitious properties.

U.S. CCP Production and U.S. CCP Production and UtilizationUtilization

►►Approximately 50% of US electricity is Approximately 50% of US electricity is generated by coalgenerated by coal--fueled power plantsfueled power plants

►►In 2005, over 123 million tons of CCP were In 2005, over 123 million tons of CCP were producedproduced

►►40% beneficially used (50 mill. tons)40% beneficially used (50 mill. tons)

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Rules regulating the use of CCPRules regulating the use of CCP

►► CCP is a RCRA D NonCCP is a RCRA D Non--hazardous material hazardous material regulated by each stateregulated by each state

►► Use of fly ash in concrete is allowed in every stateUse of fly ash in concrete is allowed in every state►► Most states exempt CCP from solid waste Most states exempt CCP from solid waste

regulations if beneficially usedregulations if beneficially usedWisconsin: Self implementing rules for five categories Wisconsin: Self implementing rules for five categories of byproducts that allow 12 types of exempted usesof byproducts that allow 12 types of exempted usesIllinois: Exempted usesIllinois: Exempted usesMichigan: Exempted uses per statute and now drafting Michigan: Exempted uses per statute and now drafting selfself--implementing rules implementing rules

Environmental Benefits of CCP Environmental Benefits of CCP UseUse

►►Reduce greenhouse gas emissionsReduce greenhouse gas emissions1 ton of fly ash that replaces cement in 1 ton of fly ash that replaces cement in concrete offsets about 1 ton of COconcrete offsets about 1 ton of CO22

►►Reduce the amount of CCP Reduce the amount of CCP landfilledlandfilled►►Conserve natural resourcesConserve natural resources►►Reduce the need for mining Improve roads Reduce the need for mining Improve roads

and buildingsand buildings►►More durable materialsMore durable materials►►Reduce lifeReduce life--cycle impacts and costscycle impacts and costs

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Green Highways PartnershipGreen Highways Partnership

www.greenhighways.org

Today fly ash is an essential Today fly ash is an essential component for durable concretecomponent for durable concrete

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CCP is stored to supply seasonal CCP is stored to supply seasonal and market demandsand market demands

QC/QA includes physical and chemical QC/QA includes physical and chemical testingtesting

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Controlled Low Strength Material Controlled Low Strength Material (CLSM)(CLSM)

CLSM using high carbonClass F fly ash and cement

CLSM using Class C fly ash and sand

Bottom ash Bottom ash subbasesubbase andandstructural bases structural bases

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Soil StabilizationSoil Stabilization

Increase the structural capacity of subIncrease the structural capacity of sub--grades using grades using cementitiouscementitious fly ashfly ash

Cold InCold In--Place Recycled PavementPlace Recycled Pavement(Full Depth Reclamation)(Full Depth Reclamation)

Make better roads using fly ash binder for Make better roads using fly ash binder for recycling asphalt or concrete pavements to recycling asphalt or concrete pavements to

make base course. make base course.

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Benefits of Full Depth Benefits of Full Depth Reclamation Reclamation

►►Reduce life cycle costsReduce life cycle costs►►Reduce construction schedulesReduce construction schedules►►Less impact on traffic during constructionLess impact on traffic during construction►►Increase structural capacityIncrease structural capacity►►Improve durability and reduce ruttingImprove durability and reduce rutting►►Improve cross sections and drainageImprove cross sections and drainage►►Resource conservationResource conservation

Costs for Full Depth Reclamation Costs for Full Depth Reclamation

►►Typical cost range $3.00/sy to $4.25/syTypical cost range $3.00/sy to $4.25/sy►►Depends on:Depends on:

Depth of pulverizationDepth of pulverizationAmount of binderAmount of binderOne or two pulverization passesOne or two pulverization passesWater truckWater truckSize of projectSize of project

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Structural Benefits: Falling Weight Structural Benefits: Falling Weight DeflectometerDeflectometer

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Pavement EvaluationPavement Evaluation

►►Falling Weight Falling Weight DeflectometerDeflectometer►►Seven Sensors: 0, 12Seven Sensors: 0, 12””, 18, 18””, 24, 24””, 36, 36””, 48, 48””, ,

and 60and 60”” from the center of loadingfrom the center of loading►►Impact Load = 40KN (9000 lbs)Impact Load = 40KN (9000 lbs)►►Performed in the outer wheel path every Performed in the outer wheel path every

100100’’

Pavement DeflectionPavement Deflection

0

2

4

6

8

10

12

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0 500 1000 1500 2000 2500 3000

Station, feet

Def

lect

ion,

mils

Year 2002Year 2001

D0

D60

2001

2002 D0

D60

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Structural Number DistributionStructural Number Distribution

012345678

0 5 10 15 20 25 30

Tests Number

Stru

ctur

al N

umbe

r

200320022001

0

200

400

600

800

1000

1200

Res

ilien

t Mod

ulus

(ksi

)

5.5 7.0 8.5

Fly Ash Content (%)

Fly Ash Content vs. Resilient Modulus

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Marquette County Presque Isle Marquette County Presque Isle Power Plant Project OverviewPower Plant Project Overview

►► 3.6 mile Landfill Haul Road3.6 mile Landfill Haul RoadOne existing asphalt pavement sectionOne existing asphalt pavement sectionTwo existing gravel sectionsTwo existing gravel sections

►► Full Depth Reclamation incorporating Bottom Ash, Full Depth Reclamation incorporating Bottom Ash, Class C Fly Ash and Cement Kiln dustClass C Fly Ash and Cement Kiln dust

Bottom ash addition 3Bottom ash addition 3”” to 4to 4”” (used 3,100 tons)(used 3,100 tons)Fly ash binder addition: 11% application rate (used Fly ash binder addition: 11% application rate (used 1,900 tons of fly ash)1,900 tons of fly ash)Cement kiln dust (CKD) also evaluatedCement kiln dust (CKD) also evaluatedGenerally did not add water Generally did not add water –– conditions were close to conditions were close to the optimum moisture at 8% to 9%the optimum moisture at 8% to 9%

►► Showed good stabilizationShowed good stabilization

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PrePre--existing Road Conditionsexisting Road Conditions

Fly Ash CompositionFly Ash Composition

►► Fly Ash from Presque Fly Ash from Presque Isle Power Plant (PIPP) Isle Power Plant (PIPP) in Marquette, MIin Marquette, MI

►► Less than 5% sulfur Less than 5% sulfur reduces swelling reduces swelling potentialpotential

►► Prefer low unburned Prefer low unburned carbon content in fly carbon content in fly ashash

63.8%63.8%39.0%39.0%18.9%18.9%5.8%5.8%2.4%2.4%18.9%18.9%1.0%1.0%

Total Silica, Aluminum, Total Silica, Aluminum, IronIronSilicon DioxideSilicon DioxideAluminum OxideAluminum OxideIron OxideIron Oxide

Sulfur TrioxideSulfur TrioxideCalcium OxideCalcium OxideLOILOI

PercentPercentPIPP Fly AshPIPP Fly Ash

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Mix DesignMix Design

►►Samples analyzed to determine maximum Samples analyzed to determine maximum densities of various mix combinationsdensities of various mix combinations

Higher dry unit weight/ fills voids with particlesHigher dry unit weight/ fills voids with particles►►Optimum moisture content needed for Optimum moisture content needed for

maximum compressive strengthmaximum compressive strengthMoisture content range 7%Moisture content range 7%--14.9%14.9%►►Target was 9%Target was 9%

Moisture was adjusted in the field to reach Moisture was adjusted in the field to reach optimum compressive strengthoptimum compressive strength

Mix DesignMix Design

Mix combinations used-25% Bottom Ash + 11% Class C Fly Ash + Reclaimed Asphaltic Material25% Bottom Ash + 11% Class C Fly Ash + Recycled Gravel Material25% Bottom Ash +11% Cement Kiln Dust + Reclaimed Asphaltic Material11% Class C Fly Ash + Reclaimed Asphaltic Material

% are by mass for fly ash and by depth of overall stabilization for bottom ash

One area was treated twice with fly ash and re-pulverized and re-compacted due to wet conditions

Taken from www.fhwa.dot.gov

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Construction SequenceConstruction Sequence

►►Bottom ash delivery, spreading and gradingBottom ash delivery, spreading and grading►►Fly ash delivery and spreadingFly ash delivery and spreading

Use of vane spreaderUse of vane spreaderBermBerm prevents fly ash from prevents fly ash from ““flowingflowing”” off the off the pavementpavement

►►Pulverization and mixingPulverization and mixing►►Water addition (when necessary)Water addition (when necessary)►►CompactionCompaction

Bottom Ash Delivery Via Live Bottom Ash Delivery Via Live Bottom Dump TruckBottom Dump Truck

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Bottom Ash Spreading and Bottom Ash Spreading and GradingGrading

Vane Spreader Minimizes Dusting Vane Spreader Minimizes Dusting and Regulates Volume of Fly Ashand Regulates Volume of Fly Ash

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Vane SpreaderVane Spreader

Why Construct a Why Construct a BermBerm??

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Transfer fly ash via tanker truck to Transfer fly ash via tanker truck to vane feeder or directly from silovane feeder or directly from silo

ReclaimationReclaimation/ Pulverization/ Pulverization

►►Water can added to obtain optimal moisture Water can added to obtain optimal moisture content and mixed in with content and mixed in with pulverizerpulverizer

►►Pulverized to 6Pulverized to 6--10 in10 in

*Taken from ARRA 2001

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Pulverization and MixingPulverization and Mixing

Pulverization during rainPulverization during rain

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Stabilizing 1 foot off pavement Stabilizing 1 foot off pavement edgeedge

PulverizerPulverizer’’ss enclosed mixing enclosed mixing chamberchamber

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Pulverization and CompactionPulverization and Compaction

CompactionCompaction

►► SheepsfootSheepsfoot roller roller compacted in vibratory compacted in vibratory mode ( 5mode ( 5--8 passes) then 8 passes) then graded immediatelygraded immediately

►► After final grading 2After final grading 2--3 3 passes with steel drum passes with steel drum rollerroller

►► Compaction between Compaction between 89.6%89.6%--98.8%98.8%

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Water additionWater addition

Compressive StrengthsCompressive Strengths

No. Mixture/Composition Moisture Content

Range (%) Dry Density (PCF)

% Compaction Range

7/28/56 Days Compressive

Strength Range (PSI)

116.5 128.41 25% BA (1-6) + 11% FAC + RAM 8.9 - 14.9 89.6 98.8

7 days 250 – 310 28 days 260 – 290 56 days 300 – 320

122.5 125.42 25% BA (1-6) + 11% FAC + RGM 7.7 - 9.1 94.5 96.5

7 days 240 – 340 28 days 290 – 330 56 days 340 – 400

124.8 127.13 25% BA (1-6) + 11% CKD + RAM 10.5 - 11.5 96 97.7

7 days 240 – 280 28 days 410 – 540 56 days 510 – 580

126.8 128.24 11% FA + RAM 8.1 - 8.3 96.9 98.6

7 days 450 – 460 28 days 360 – 490 56 days 390 – 460

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PIPP Haul RoadFull Depth Reclamation Compressive Strength

FAC

+ B

A +

RAM

FAC

+ B

A +

RAM

FAC

+ B

A +

RAM

FAC

+ B

A +

RA

M

CKD

+ B

A +

RAM

CKD

+ B

A +

RA

M

CKD

+ B

A +

RA

M

CKD

+ B

A +

RA

M

FAC

+ R

AM

FAC

+ R

AM

FAC

+ R

AM

FAC

+ R

AM

FAC

+ B

A +

GR

AVE

L

FAC

+ B

A +

GR

AVEL

FAC

+ B

A +

GR

AVEL

FAC

+ B

A +

GR

AVEL

0

100

200

300

400

500

600

Days

Avg

. Com

pres

sive

Str

engt

h (p

si)

3 7 28 56

Field QC /QAField QC /QA

Molding cylinders for compressive strength using standard proctor equipment

Moisture and density

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Asphalt PavementAsphalt Pavement

►►Light rain for three days during projectLight rain for three days during projectWork was able to continueWork was able to continueWater repelled on stabilized soil similar to a Water repelled on stabilized soil similar to a

paved surfacepaved surface

►►This allowed soils to be ready for paving This allowed soils to be ready for paving when weather was conducive to pavingwhen weather was conducive to paving

Asphalt PavementAsphalt Pavement

►► Fly ash Section 3Fly ash Section 3--1/2 in. of asphalt pavement1/2 in. of asphalt pavement►► NonNon--fly ash stabilized section 4 in. of asphalt fly ash stabilized section 4 in. of asphalt

pavementpavement►► Thinner placement because structural coefficient Thinner placement because structural coefficient

increased from .14 to .28increased from .14 to .28--.30.30►► Stabilized shoulders allowed loads at outer edges Stabilized shoulders allowed loads at outer edges

of the pavement to be uniformly supportedof the pavement to be uniformly supported

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RegulationsRegulations

►►Allowed under paved Allowed under paved roads roads -- considered considered part of structural pavementpart of structural pavement

►►Blending done quickly after fly ash was Blending done quickly after fly ash was placed to keep fly ash from spreading placed to keep fly ash from spreading outside of roadoutside of road

►►Dust keeped to a minimum Dust keeped to a minimum –– drop height of drop height of fly ash was minimized on vane truckfly ash was minimized on vane truck

RegulationsRegulations

►►100 tons Coal Combustion Products (100 tons Coal Combustion Products (CCPsCCPs) ) and CKD allowed per project outside of and CKD allowed per project outside of structural pavementstructural pavement

►►Total Total CCPCCP’’ss and and CKDsCKDs used=5160 tonsused=5160 tons►►On unpaved section (shoulder)=210 tonsOn unpaved section (shoulder)=210 tons►►Equals 70 tons in each section (project) Equals 70 tons in each section (project)

which is within the limitwhich is within the limit

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SummarySummary

►► Pilot projects used fly Pilot projects used fly ash, bottom ash and ash, bottom ash and kiln dust; kiln dust;

►► Reduced use of new Reduced use of new materials and reuses materials and reuses materialmaterial

►► We Energies will seek We Energies will seek source exemption from source exemption from DEQ for use beyond DEQ for use beyond edge of pavement edge of pavement

Bottom ash being taken from landfill site

SummarySummary

►►Showed increased dry densityShowed increased dry density►►Increased load bearing capacityIncreased load bearing capacity►►Increased savings using fly ash over cement Increased savings using fly ash over cement

or limeor lime►►Overall viable option when designing Overall viable option when designing

roadwaysroadways►►Accelerates construction scheduleAccelerates construction schedule►►Contractors were able to construct with little Contractors were able to construct with little

difficultydifficulty

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Website ReferencesWebsite References►► American Coal Ash Assoc.American Coal Ash Assoc. www.acaawww.acaa--usa.orgusa.org►► Michigan Tech Michigan Tech www.imp.mtu.eduwww.imp.mtu.edu►► UWUW--MilwaukeeMilwaukee www.cbu.uwm.eduwww.cbu.uwm.edu►► Univ. North Dakota Energy & Environmental Research Univ. North Dakota Energy & Environmental Research

CenterCenter www.undeerc.org/carrcwww.undeerc.org/carrc►► DOE National Energy Technology LaboratoryDOE National Energy Technology Laboratory

www.fetc.doe.govwww.fetc.doe.gov►► Univ. of Kentucky Center for Applied Energy ResearchUniv. of Kentucky Center for Applied Energy Research

www.caer.uky.eduwww.caer.uky.edu►► U.S. EPA U.S. EPA http://www.epa.gov/epaoswer/osw/conserve/c2p2/http://www.epa.gov/epaoswer/osw/conserve/c2p2/►► We EnergiesWe Energies

www.wwww.wee--energies.com/environmental/recycle_coalash.htmenergies.com/environmental/recycle_coalash.htm

ContactsContacts

►► Dr. Tom Van Dam Dr. Tom Van Dam –– MTUMTU 906906--487487--25242524►► Tom Jansen Tom Jansen –– We EnergiesWe Energies 414414--221221--24572457►► Art Art CoviCovi –– We EnergiesWe Energies 414414--221221--46184618►► Jeff Jeff DusseaultDusseault –– MRTMRT 906906--226226--29912991►► Dave Dave DiedrickDiedrick –– LafargeLafarge 248248--593593--27142714