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Asphalt Expert Task Group Update and Emerging Topics...RAP/RAS Task Force within ETG: • AASHTO PP...

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  • AsphaltExpertTaskGroupUpdateandEmergingTopics

    MatthewCorrigan,P.E.U.S.DOT|FederalHighwayAdministration

    Preconstruction,Construction,andPavementsOctober2017

  • • ForumforGovernment,Industry,andAcademia

    • Discussionofongoingasphaltbinderandmixturetechnology

    • Providetechnicalinputforcurrentandfutureresearch,development,andspecifications.

    AsphaltExpertTaskGroups

  • • AsphaltMixture&ConstructionETG• LastmeetinginBozemanonSept20-21,2017• POC– MatthewCorrigan

    • AsphaltBinderETG• LastmeetinginBozemanonSept19-20,2017• POC– MatthewCorrigan

    • SustainablePavementsTWG• POC– GinaAhlstrom

    AsphaltExpertTaskGroups

    OpenMeetingsAllareWelcome!

  • www.AsphaltETGs.org

    UpcomingETGMeetingsToBeAnnounced(Nexttentative- weekofApril23,2018)

    PastETGMeetingsSeptember2017— Bozeman,MTMay2017— Ames,IASeptember2016— FallRiver,MAApril2016— SaltLakeCity,UTSeptember2015— OklahomaCity,OKApril2015—FallRiver,MASeptember2014—BatonRouge,LA

  • • AsphaltMixturePerformanceTester(AMPT)• PerformanceTestsforCracking/Fatigue• RAP&RASAsphaltBinderReplacement

    • PerformanceRelated/BasedSpecifications• ΔTc andrelatedrheologicalparameters• ProvidetechnicalinputtoAASHTOCommitteeon

    Materials&Pavements(COMP)&assistimprovement,revision,andupdateofstandardsandspecifications

    CurrentAsphaltETG- Activities

    • BalancedMixDesign• MSCRBinderGrading• GroundTireRubber

  • • ResultsusedforMEDesignandPRS/PBSinputs• AdoptedAASHTOStandards(2017):

    – R83-17forpreparationofAMPTtestspecimens– T378-17forDynamicModulus|E*|andFlowNumber(Fn)

    – R84-17fordeveloping|E*|mastercurves– TP107-14(2016)forCyclicFatigue(cracking)– anddraftTPXXforStressSweepRutting

    AsphaltMixPerformanceTester(AMPT)www.fhwa.dot.gov/pavement/asphalt/tester.cfm

    AlreadyinvestedinAMPTequipmentforPavementME …theAMPTcandomuchmorethanjust|E*|testing!!

  • 1. Heritageand“pedigree”ofthetheory–aerospaceindustryapplicationforsolidrocketpropellant

    2. Needforaperformancetestthatwouldbedefensible,not empiricalcorrelations

    3. AASHTOTP107-14(2016)DeterminingtheDamageCharacteristicCurveofAsphaltMixturefromDirectTensionCyclicFatigueTests

    4. Connectmixdesign,construction,andacceptancebymeansofdistressandperformanceprediction- notjustapass/failtest

    WhyAMPTCyclicFatigueTest?

    *RefertoETGPresentationatpreviousNEAUPGforsignificantlymoredetails

    *

  • 5. Thetesttellsyoualotaboutyourmix!!!– Responseundermultiplestrains:

    STRUCTURE/TRAFFIC– Responseundermultipleloadrates:TRAFFIC– Responseundermultipletemperatures:SEASONAL– Moreinformationgainedfromthistestprotocoland

    analysisthanfromothersingletestsatasinglerate/temperature

    6. Connectmixdesign,construction,andacceptancebymeansofdistressandperformanceprediction- notjustapass/failtest

    WhyAMPTCyclicFatigueTest?

  • RAP/RASTaskForcewithinETG:• AASHTOPP78-17DesignConsiderationsforRAS• ImprovementstoM323Superpave Design

    – Table2vsTable3requirementsandlimits– Definitions(PbRAP),references(MSCR&LTPPBind),appendices,editorial,andorganization

    – RAPbinderratio(RAPBR)emphasiswithbindergradeadjustmentguidelines

    – EvaluateblendedbinderpropertiestoalignwithPP78recommendations

    – FuturegoaltoincorporatebothcombinedRAP&RASmaterialstogetheringuidance

    ReclaimedAsphaltPavement(RAP)ReclaimedAsphaltShingles(RAS)

  • ETGRAP/RASTaskForce

    Focusonthebrittlenessoftheblended binder:• EstimatebrittlenessoftheblendedbinderwiththeBendingBeamRheometer(BBR)

    ΔTc =Stiffnesscriticaltemp(S)– theRelaxationcriticaltemp(m-value)

    • PreviousworkbyM.Anderson,T.Bennert,G.ReinkeindicatesthatwhenΔTc < -5°Cthereisasignificantlossofcrackingresistance.

  • BalancedMixDesignTaskForce

    • Threemainapproacheswereidentifiedforpotentialuse:

    Fordetails,refertothe18Oct2017NEAUPG.pptprovidedbyShaneBuchanan

  • BalancedMixDesignTaskForce

    CurrentActivities• InformationOutreach

    • PresentBMDconcepts• HighlightthebenefitofBMDconcepts

    • FieldAcceptance• DefinevariousapproachesforacceptanceprotocolswithinaBMDapproach

  • PerformanceRelatedSpecifications

    “QAspecificationsthatdescribethedesiredlevelsofkeymaterialsandconstructionqualitycharacteristics thathavebeenfoundtocorrelatewithfundamentalengineeringpropertiesthatpredictperformance”

    TransportationResearchCircularNumberE-C137GlossaryofHighwayQualityAssuranceTerms

  • IdentifyAQCsandTargetValues

    EstablishPerformanceCriteria

    ModelPerformance

    DesignAQCvs.As-ConstructedAQC

    CompareAs-BuiltandAs-Designed

    PayFactorTime

    Design

    Constructed

    SOFTWARE

    Value of Performance?

    HowPRSWorksPlanning

    PavementDesign

  • BenefitsofPRS

    • Longtermpavementperformancepredictedfromfundamentalengineeringproperties

    • Incentivesanddisincentives justifiedthroughreductionorincreaseinpavementlife

    • Allowcontractorsflexibilitytobeinnovative andcompetitive

  • PRSInitiative

    • Useoffundamentalteststocapturevariancebetweenas-designedandas-builtAQCs

    • AsphaltMixturePerformanceTester(AMPT)usedinmixturedesign

    • Performancevolumetricrelationshipsusedinconstruction

    • Structuralresponsemodel(stressesandstrains)

  • PRSInitiative

    • Fundamental– Howmuchdistress?Howmuchlife?– Stressesandstrains– Materialproperties(i.e.,modulus)– Usewithstructuralresponsemodel– Manytemperature/loadingconditionsrepresented

    • Index-Based– Go/no-go:correlation-based– Someengineeringproperties,someempirical

    • Moretiedtoamaterialdatabase– Notusedwithastructuralresponsemodel(FlexPAVE)– Onlyafewtemperature/loadingconditionsrepresented

    FHWAPRS

    Cost-efficientwaytoaccountforrelevantdistress!!

  • FlexMATTM andFlexPAVETM Available

    • FlexMATTM – Excelspreadsheet– Analyzescyclicfatigue,|E*|,andSSRdata– Importfilesdirectly– Outputà FlexPAVETM

    • FlexPAVETM – performancepredictiontool– PEMDthroughacceptance– Simulateas-designandas-builtperformance

  • FlexMATTM andFlexPAVETM Available

    • FlexMATTM – Excelspreadsheet– Analyzescyclicfatigue,|E*|,andSSRdata– Importfilesdirectly– Outputà FlexPAVETM

    • FlexPAVETM – performancepredictiontool– PEMDthroughacceptance– Simulateas-designandas-builtperformance

    PredictsPerformance!!

  • MaterialBehaviorAcrossAllLoadingConditions

    • Time-temperaturesuperposition– Majorbenefit– Reducestestingtime– Enablesrobustnessofmodels

    • Fundamentalpropertiesrequiredtodescribebehavioracrosswide-rangeofconditions

    • Allowsfordirectincorporationofpavementstructureintopredictions

  • MaterialBehaviorAcrossAllLoadingConditions

    • Time-temperaturesuperposition– Majorbenefit– Reducestestingtime– Enablesrobustnessofmodels

    • Fundamentalpropertiesrequiredtodescribebehavioracrosswide-rangeofconditions

    • Allowsfordirectincorporationofpavementstructureintopredictions

  • FHWAisworkingwiththeAsphaltInstitutetoassistStatestoeffectivelyunderstandandimplementMSCR.• TechnicalBriefFHWA-HIF-11-038

    – www.fhwa.dot.gov/pavement/asphalt/index.cfm

    • ResourcespostedonAI’swebsite– www.asphaltinstitute.org/public/engineering/mscr-information.dot

    MultipleStressCreepRecovery(MSCR)

  • • AASHTOT350-14andM332-14• EmphasisondeterminingJnrdiff

    – Jnr changewithstressincrease– ImpactofstressselectiononJnr whilestayingwithinthebinder’slinearrange

    – Jnr slopedetermination– EgradeJnrdiff waiver

    MSCR Jnrdiff TaskForce

  • • ExtensivedevelopmentworkconductedonrubbermodifiedbinderwithCCgeometry– Revealsthepracticalandrheologicalchallenges– SuitablemeasuringgeometryforPGmeasurementsofgroundtirerubbermodifiedasphaltbinders

    – Finalizedtooldimensionsandrequirements• DSR…concentriccylindergeometryalsocalled“Cup&Bob”geometry– “requiredtoenablegoodrheology!”…“Gapsizematters!”

    DSRConcentricCylinder(CC)TaskForce

  • Smallcylinderinsideabigcylinderenablestheuseoflargegaps

    AbsoluteRelative CC17SPGap≈6.2mmSuitableforneatandRTFOasphaltbinder(highPGtemperatures)

    CC10SPGap≈9.5mmSuitableforPAVasphaltbinder(intermediatePGtemperatures)

    CourtesyofA

    nton

    Paar

  • DraftAASHTOteststandarddevelopment• TPXX-YYDeterminingtheRheologicalPropertiesofAsphaltBinderContainingGroundTireRubberParticulatesUsingConcentricCylinderGeometryintheDynamicShearRheometer(DSR)– PGHightemperaturecharacterization– Proceduretocalibrate/verifytorqueandtemperature

    • Future– RTFOagingandBBRtesting

    DSRConcentricCylinder(CC)TaskForce

  • TaskForcewithinETG• Draftwhitepaperfinalized(tobepublished)• Whichrheologicalparameter

    – criticaltemperaturechange(ΔTc)– Glover-Rowe(GR)– rheologicalindex(Rvalue)– crossoverfrequency(ωc)

    • Alloftheseparameterscanbeinterrelatedfromunderstandingtherelationshipbetweenloadingtime(orfrequency)andtemperature.

    Re-refinedEngineOilBottoms(REOB)VacuumTowerAsphaltExtender(VTAE)

  • Focusonthebrittlenessoftheblended binder:• EstimatebrittlenessoftheblendedbinderwiththeBendingBeamRheometer(BBR)

    ΔTc =Stiffnesscriticaltemp(S)– theRelaxationcriticaltemp(m-value)

    • PreviousworkbyM.Anderson,T.Bennert,G.ReinkeindicatesthatwhenΔTc < -5°Cthereisasignificantlossofcrackingresistance.

    ΔTc andrelatedrheologicalparameters

  • • Current20hourPAVdoesnotrepresentenoughagingtoidentifycriticalconditionsortomatchfieldagingbypavements

    • 40hourPAVcorrelatedwithperformance• Optionsforachievingadditionalagingarebeingexplored– Thinnerasphaltfilms

    • PAVorUSAT(UniversalSimpleAgingTest)– PredictedΔTc fromdifferencebetween:

    • Rateofchange:originalbindertoRTFOTto20hourPAV

    ΔTc andrelatedrheologicalparameters

  • • Otherparametersthatprovidesimilarinfo?– AgingdecreasesΔTc,increasesR-value,decreasescrossoverfrequency,andincreasescrossovertemperature

    • RelationshipbetweenΔTc andTwc– Crossovertemperature(Twc)– measuredat10radians/secwherethephaseangleis45°ortand =1

    – Twc iseasytomeasureonRTFOagedbinder

    ΔTc andrelatedrheologicalparameters

  • • Laboratoriesroutinelyconfusebarometricpressurewiththebarometricpressurereportedbythelocalweatherstation– Barometricpressurereportedbylocalweatherstationiscorrected tosealevel

    • Uselessforourpurposes!– Absolutevacuumgageshouldbespecified– Tievacuumleveltoelevation

    PAVDegassing

  • Whenusingavacuumgagetocontrolthedegassingpressure,thegaugereadingsgivenbyEq.4calculatedusingthelaboratoryelevationtothenearest100feetshallbeusedtocontrolandreportthevacuumduringthedegassingcycle.Equation4accountsforchangesinatmosphericpressurewithelevation.Noadditionalcorrectionsforlaboratorybarometricpressure,temperature,humidity,etc.shallbeappliedtothevacuumgagereadingregardlessofinstructionssuppliedbyanyvendors,instrumentsoftware,orothersource.Thevacuumgagereadingshallbereportedandcontrolledtothenearest0.5inHg(0.2kPa).

    PAVDegassing- Proposal

  • • TheabsolutepressurecalculatedinaccordancewithEq.4shallbe5.0±0.50inchesofmercury(17± 1.7kPa).

    • Asaminimumthegageshallbereadandreportedtothenearest0.5inchesHg(2kPa)

    PAVDegassing- Proposal

  • 1.Howcanwemeasurepanflatness?a. Currenttechniquesarenotsatisfactory

    2.Howdoweobtaindirectmeasureofflatness?a. Profileisneeded

    3.Howdotypicalpanflatnesserrorsaffecttestresults?a. Ifflatnessandpropertyvs.thicknessdata

    areavailable,itcanbeestimatedb. Determinedexperimentallybyusing

    warpedpans

    PAVPanWarping

  • 4. Howcanwemeasurepanflatnessinspecificationscenario?

    5. Whatarerealisticlimitsforspecifyingpanflatness?

    PPAVPanWarping

    MeasuringjigandphotoprovidedbyDr.DavidAnderson

  • • Pandividedinto28segments• Profilemeasuredatcentroidofeachprofile

    • Propertiesforeachsegmentcanbeweightedaslongaseffectofthicknessonpropertiesisknown

    • Canalsoestimateeffectofpanandvessellevelness

    ProfilingandCalculatedEffect

  • ProfilingandCalculatedEffect

    CourtesyofDr.DavidAnderson

  • • A1%increaseinfielddensity(1%lessairvoids)canincreaseasphaltpavementservice-life10+%!(conservatively)

    • Today’scompactiontargetistypically92%ofmaximum(Gmm )(8%airvoids),withvaryingrequirementsfortheareanearthelongitudinaljoint

    EnhancedDurabilitythroughIncreasedIn-PlacePavementDensity

    IncreasedDensityPavementstargeta1-2%increaseacrosstheentirepavement!

    – Just1%more…makesahugedifference!

  • CA

    AZ

    CO

    NM

    TX

    OK AR

    LA

    MO KY

    AL GA

    FL

    VA

    OH

    MI

    AK

    MT

    NV

    MEWA

    OR

    UT

    KS

    ID

    WY

    ND

    SD

    MN

    NE

    WI

    IA

    IL IN

    MS

    TNSC

    NC

    WV

    PA

    NY

    CTNJDEMD

    DCHI

    Key:

    PR

    Demonstration projects (10)

    EnhancedDurabilityofAsphaltPavementsthroughIncreasedIn-Place

    PavementDensity

    Workshop Only (18)

    Mobile AsphaltTesting Trailer (2)

    EasternFederalLands

  • • Fieldexperiment– Phase1– 10statesselected– Projectscompletedin2016

    • Extendfieldexperiment– Phase2– 9statesselected– Projectsunderconstructionin2017andearly2018

    • Potentialadditionalfieldprojectsin2018?• FHWA’sbestpracticescommunication

    – Summarydocument– TechBrief– Additionalworkshops(fundingdependent)

    NextSteps

  • CA

    AZ

    CO

    NM

    TX

    OK AR

    LA

    MO KY

    AL GA

    FL

    VA

    OH

    MI

    AK

    MT

    NV

    MEWA

    OR

    UT

    KS

    ID

    WY

    ND

    SD

    MN

    NE

    WI

    IA

    IL IN

    MS

    TNSC

    NC

    WV

    PA

    NY

    CTNJDEMD

    DCHI

    Key:

    PR

    Demonstration projects (10)

    EnhancedDurabilityofAsphaltPavementsthroughIncreasedIn-Place

    PavementDensity

    Workshop Only (18)

    Mobile AsphaltTesting Trailer (2)

    EasternFederalLands

    Ph. 2 Demonstration (9)

  • SummaryDocument

    http://eng.auburn.edu/research/centers/ncat/files/technical-reports/rep17-05.pdf

    NCATReport17-05

    “DemonstrationProjectforEnhancedDurabilityofAsphaltPavementsthroughIncreasedIn-placePavementDensity”- July2017

  • Testsectionshadincreased%TMD:• 8of10statesachieved>1.0%increase• 7of10statesachieved>94.0%Gmm• 6of10statesachieved>95.0%GmmWilltherebechanges?• 7of10statesarechangingspecifications

    Canweachieveincreaseddensity?

  • • MobileAsphaltPavementMaterialsLab– SiteVisits– FieldData/Testing/Evaluation– Use/DemoEmergingTestDevices– POC:MatthewCorriganand

    DavidMensching

    FHWAFieldSupportMobileAsphaltTestingTrailer(MATT)

  • You!!Thank Discussion/Comments/Questions

    FHWA’sMobileAsphaltTestingTrailerOfficeofAssetManagement,Pavement,andConstruction

    www.fhwa.dot.gov/pavement/asphalt

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Asphalt Expert Task Group Update and Emerging Topics Matthew Corrigan, P.E. U.S. DOT | Federal Highway Administration Preconstruction, Construction, and Pavements October 2017
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