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Investigation of the Restricted Zone in the Superpave Aggregate Gradation Specifications

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    INVESTIGATIONOFTHERESTRICTED

    ZONEINTHESUPERPAVEAGGREGATEGRADATIONSPECIFICATION

    by

    PrithviS.KandhalAssociateDirector

    L.AllenCooley,Jr.ResearchEngineer

    NationalCenterforAsphaltTechnology

    PaperpublishedintheJournaloftheAssociationofAsphaltPavingTechnologists,AsphaltPavingTechnology,Volume71,2002

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    INVESTIGATIONOFTHERESTRICTEDZONEINTHE SUPERPAVEAGGREGATEGRADATIONSPECIFICATION

    PrithviS.KandhalandL.AllenCooleyJr.1

    ABSTRACT

    TherecommendedaggregatespecificationforSuperpavehotmix

    asphalt(HMA)mixturesincludesarestrictedzonewhichliesalongthemaximumdensitygradationbetweentheintermediatesize(either4.75or

    2.36mm,dependingonthenominalmaximumsizeoftheaggregate)and

    the300:msize.Therestrictedzoneformsabandthroughwhichgradationswererecommendednottopass.Therestrictedzone

    requirementwasadoptedinSuperpavetohelpreducetheincidenceoftenderorrut-proneHMAmixes.

    Accordingtomanyasphaltpavingtechnologists,compliancewiththerestrictedzonecriteriamaynotbedesirableornecessarytoproducepavingmixesthatgivegoodperformance.Somehighwayagenciesand supplierscanprovideexamplesofaggregategradationsthatpassthrough therestrictedzone,butproducepavingmixesthathavehistorically

    performedwell.Thisresearchprojectwasundertakentoevaluatetheeffectofthe

    Superpaverestrictedzoneonpermanentdeformationofdense-graded HMAmixtures.Itsprimaryobjectivewastodetermineunderwhat

    conditions,ifany,compliancewiththerestrictedzonerequirementis necessarywhenalltheotherSuperpaverequirementssuchasfine aggregateangularity(FAA)andvolumetricmixcriteriaforthespecific

    project.Thefollowingfactorswereevaluated:twocoarseaggregates,ten

    fineaggregates,twonominalmaximumaggregatesizemixes(9.5and19.0mm),fiveaggregategradations,andthreecompactiveefforts

    (Ndesign=75,100,and125).Ofthefivegradationsused,threeviolatethe restrictedzoneandtwofalloutsideoftherestrictedzone(control). PermanentdeformationcharacteristicsofmixesmeetingSuperpave volumetricrequirementswereevaluatedbytwodifferenttypesoftests:

    empiricalandfundamental.Fortheempiricaltest,theAsphaltPavementAnalyzerwasused.TheSuperpavesheartesterandarepeatedload confinedcreeptestwereutilizedasfundamentaltests.Testresultsfrom

    1

    Respectively,associatedirectorandresearchengineer,NationalCenterfor

    AsphaltTechnology,AuburnUniversity.

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    thethreemechanicaltestswereanalyzedstatisticallytoevaluatetheeffectofthefivegradationsonpermanentdeformationoftheHMA

    mixtures.Basedupontheanalysisofdata,mixeshavinggradationspassingthroughtherestrictedzonedidnotnecessarilyhavelowerrut

    resistancecomparedtomixeshavinggradationsoutsidetherestricted zone.Itwasrecommendedtodeletetherestrictedzoneasaguidelineor

    requirementinSuperpavemixdesign.KEYWORDS:Superpave,asphaltmixtures,HMA,asphaltconcrete,gradation,restrictedzone,permanentdeformation,rutting

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    INVESTIGATIONOFTHERESTRICTEDZONEINTHE SUPERPAVEAGGREGATEGRADATIONSPECIFICATION

    INTRODUCTION

    TheStrategicHighwayResearchProgram's(SHRP)asphaltresearchwasprimarilyaimedatthepropertiesofasphaltbindersand

    HMAmixesandtheireffectonasphaltpavementperformance.The

    studyofaggregateproperties(includinggradation)wasintentionallyexcludedfromtheasphaltresearchprogram.Yet,theSHRPresearchers hadtorecommendasetofaggregatepropertiesandanaggregate gradationspecificationwithoutthebenefitofexperimentationsothata

    comprehensiveSuperpavemixdesignsystemcouldbeformulated. SHRPformedanAggregateExpertTaskGroup(ETG)consistingof

    14acknowledgedexpertsintheareaofaggregates.Inlieuofaformal aggregateresearchprogram,theaggregateETGusedamodifiedDelphi approachtodevelopasetofrecommendedaggregatepropertiesandcriteriathatarenowincludedintheSuperpavevolumetricmixdesignmethod(AASHTOMP2andPP28).TheDelphiprocesswasconducted withfiveroundsofquestionnaires.Thefinalrecommendedaggregate

    gradationcriteriaincludedcontrolpointsbetweenwhichthegradationmustfallaswellasarestrictedzonethatliesalongthemaximumdensityline(MDL)betweentheintermediatesize(either4.75or2.36mm

    dependingonthenominalmaximumsizeoftheaggregateinthemix)andthe0.3mmsize(1).

    AlthoughtherestrictedzonewasincludedinSuperpaveasa recommendedguidelineandnotarequiredspecification,somehighwayagenciesinterpreteditasarequirement.Manyasphalttechnologists

    believethatcompliancewiththerestrictedzonecriteriamaynotbedesirableornecessaryineverycasetoproduceasphaltmixeswithgood

    performance.Ifhighlyangularaggregatesareusedinthemixitislikely

    thatthemixwillnotexhibitanytendernessduringconstructionandwill

    berut-resistantundertrafficregardlessifitsgradationpassesthroughtherestrictedzone.TheGeorgiaDepartmentofTransportationhasused

    suchmixessuccessfullyformanyyears(2).Someasphalttechnologists

    alsoquestiontheneedfortherestrictedzonewhenthemixhastomeet

    volumetricpropertiessuchasminimumvoidsinthemineralaggregate

    (VMA)andspecifiedairvoidcontentsatNinitial,Ndesign,andNmaximum

    1

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    gyrations.

    OBJECTIVE

    Thisresearchwascarriedouttoevaluatetheeffectofrestrictedzoneonmixperformanceonthebasisofastatisticallyplannedandproperlycontrolledexperiment.Itsprimaryobjectivewastodetermineunderwhatconditions,ifany,compliancewiththerestrictedzone requirementisnecessarywhenthehotmixasphalt(HMA)meetsallotherSuperpaverequirementssuchasfineaggregateangularity(FAA)

    andvolumetricmixcriteriaforthespecificproject.

    SELECTIONOFMATERIALS

    Materialsneededforthisstudyconsistedofcoarseaggregates,fine aggregates,andanasphaltbinder.Twocoarseaggregates,tenfine aggregates,andoneasphaltbinderwereused.Thefollowingsections describethematerialsselectedforthisstudyalongwithpropertiesofthe

    selectedmaterials.

    CoarseAggregates

    Twocoarseaggregates,crushedgraniteandcrushedgravel,were

    usedforthisstudy.Selectioncriteriaforthesetwocoarseaggregateswasthattheyshouldcomefromdifferentmineralogicaltypesandhave

    differentparticleshapesandtextures.Propertiesofthesetwocoarse

    aggregatesareprovidedinTable1.

    FineAggregates

    Sincetherestrictedzoneisappliedwithinthefineaggregatesievesizes,theshapeandtextureofthefineaggregatesarethemostimportant factorsaffectingtheperformanceofHMAmixtures.Therefore,the approachtakeninidentifyingandselectingfineaggregatesforuseinthisstudywastoselectaggregateswithvaryingvaluesoffineaggregate

    angularity(FAA).Alsoincludedwithintheselectioncriteriawasmineralogicalcomposition.Maximizationofthesecriteriaensuredusing

    fineaggregateswithawiderangeofproperties. Thetenselectedfineaggregatesalongwiththeirmineralogicaltype

    andFAAvalue(AASHTOT304)areprovidedinTable2.Sixdifferentmineralogicaltypeshavebeenselectedandinclude:naturalsands,

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    sandstone,dolomite,limestone,granite,anddiabase(traprock).FAAvalues

    ofthetenfineaggregatesrangedfrom38.6to50.3percent.

    Table1:CoarseAggregateProperties

    Test

    FlatorElongated2:1,%

    FlatorElongated3:1,%

    FlatorElongated5:1,%

    FlatandElongated2:1,%

    FlatandElongated5:1,%

    UncompactedVoids,%(MethodA)

    ApparentSpecificGravityBulkSpecificGravity

    WaterAbsorption,%

    LosAngelesAbrasion,%loss

    CoarseAggregate

    Angularity%1FF,%2

    FF

    Procedure

    ASTM

    D4791

    ASTM

    D4791ASTM

    D4791

    ASTM

    D4791

    ASTM

    D4791

    AASHTO

    TP56

    AASHTO

    T84

    AASHTO

    T85

    AASHTO

    T85

    AASHTO

    ASTM

    D5821

    Crushed

    Gravel

    20

    2

    0

    40.1

    0

    41.7

    2.6422.591

    0.7

    28

    100/92

    Granite

    57

    11

    1

    64.3

    1.0

    47.0

    2.7242.675

    0.6

    41

    100/100

    FA-10wasincludedtoprovidea"worstcase"referencepointfor

    comparingtheresponsevariablesdescribedlaterinthispaper.FA-10

    purposelyhadanFAAvaluebelow40(FAA=38.6).

    AsphaltBinder

    TheasphaltbinderselectedforthisstudywasaSuperpave

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    performance-basedPG64-22whichisoneofthemostcommonlyusedgradesintheUnitedStates.Propertiesofthisasphaltbinderareprovidedelsewhere(3).

    Table2:FineAggregatesSelectedforStudy

    Fine FAA Type Bulk %Abs. CommentsAgg. Value Sp.Gr.

    FA-1 40.7 RiverSand 2.610 0.2 Washed,uncrushed,riverdepositcomprisedof predominantlyquartz,fromKentucky

    FA-2 42.6 Quartz 2.568 1.4 Noprocessing,naturalquartzriverdepositwithsome Sand chert,fromTennessee

    FA-3 44.1 Natural 2.638 0.4 Uncrushed,naturalquartzsandwithsomechert,from

    Sand Alabama

    FA-4 49.7 Sandstone 2.731 0.8 Mined,conecrusher,fromAlabama

    FA-5 50.3 Dolomite 2.822 0.5 Mined,conecrusher,fromAlabama

    FA-6 46.9 Limestone 2.661 1.0 Mined,samesourceasFA-8butcrushedbyimpact

    crusher,fromAlabama

    FA-7 48.9 Granite 2.711 0.4 Mined,conecrusher,fromMinnesota,usedonMnRoad

    FA-8 48.3 Limestone 2.648 1.7 Mined,samesourceasFA-6butcrushedbyconecrusher,fromAlabama

    FA-9 50.1 Diabase 2.909 0.8 Mined,impactcrusher,fromVirginia

    FA- 38.6 Natural 2.636 0.3 DredgedstreamdepositfromMississippi10 Sand

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    EXPERIMENTALPLAN

    TheoverallresearchapproachisshowninFigure1.Thisfigure illustratesthattheresearcheffortwasbrokenintothreepartstomaximizetheinformationobtained.Thedetailedworkplansforthethree

    Figure1:OverallResearchApproach

    partsaredescribedasfollows.

    Part1WorkPlan

    Factor-levelcombinationsincludedinPart1consistedoftwocoarse aggregates,tenfineaggregates,five9.5mmnominalmaximumaggregatesize(NMAS)gradations,andonecompactiveeffort.Ofthe fivegradationsusedinPart1,threeviolatetherestrictedzonewhiletwo resideoutsidetherestrictedzone(control).Thesefivegradationsare giveninTable3andillustratedinFigure2.Thecompactiveeffortused

    duringPart1wasthatforadesigntrafficlevelof3-30millionESALs (20year).Theinitial,design,andmaximumnumberofgyrationsforthis

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    designtrafficlevelare8,100,and160,respectively.

    Table3:9.5mmNominalMaximumSizeGradationsUsedin Parts1and2

    Sieve, BRZ ARZ TRZ HRZ CRZ

    mm

    12.5 100 100 100 100 100

    9.5 95 95 95 95 95

    4.75 60 60 60 60 60

    2.36

    42

    50

    46

    46

    52

    1.18 28 42 34 34 34

    0.60 18 32 24 30 20

    0.30 14 22 18 24 14

    0.15 10 10 10 10 10

    0.075 55 55 5

    BRZ-BelowtheRestrictedZone HRZ-HumpedThroughtheRestrictedZone

    ARZ-AbovetheRestrictedZone CRZ-CrossoverThroughtheRestrictedZone

    TRZ-ThroughtheRestrictedZone

    AsillustratedinFigure2,allfivegradationsfollowthesametrend

    fromthe12.5mmsievedowntothe4.75mmsieve.Fromthe4.75mmsieve,theBRZ(belowrestrictedzone)gradationpassesbelowthe restrictedzoneandabovethelowercontrolpoints.TheARZ(above restrictedzone)gradationpassesabovetherestrictedzoneandbelowthe uppercontrolpoints.Thesetwogradationsaredesignatedthecontrol gradationssincetheydonotviolatetheSuperpaverestrictedzone.Figure 2showsthattheremainingthreegradationsdoviolatetherestricted zone.Fromthe4.75mmsieve,theTRZ(throughrestrictedzone)

    gradationpassesalmostdirectlyalongthemaximumdensityline.TheHRZ(humpedthroughrestrictedzone)gradationfollowsasimilargradationastheTRZgradationdowntothe1.18mmsievewhereit humpsonthe0.6and0.3mmsievesandrepresentsgradationsgenerally containingalargepercentageofnatural,windblownsands.Fromthe

    4.75mmsieve,theCRZ(crossoverthroughrestrictedzone)gradation

    beginsabovetherestrictedzoneonthe2.36mmsievebutthencrosses

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    Part1Gradations

    ControlPoints ResrictedZone BRZ ARZ TRZ Hump Crossover

    1009080706050403020100

    0.075 0.30 0.60 1.18 2.36 4.75 9.5 12.5SieveSize,mm

    Figure2:Part1Gradations

    throughtherestrictedzonebetweenthe0.6and0.3mmsieves.TheCRZgradationrepresentsgradationswhicharenotcontinuouslygraded between2.36mmand0.60mmsizesandgenerallyexhibitlowmix

    stability.Allfiveofthegradationsthenmeetatthe0.15mmsieveandfollowthesametrenddowntothe0.075mmsieve.Acommonmaterialpassing0.075mm(No.200)sieve(P200)wasusedinallHMAmixtures toeliminateP200asavariable.DifferentP200materialsstiffentheasphaltbinderandHMAmixturestoadifferentdegreeand,therefore,affectthemixperformancetestresults.Alimestonefiller(Rigden

    voids=33.5%)wasutilizedastheP200. FA-10fineaggregatewascombinedwiththetwocoarseaggregates

    onlyfortheHRZgradation.FineaggregateshavinganFAAvalue greaterthan45werenotusedintheHRZgradationbecausetheHRZgradationisindicativeofgradationshavingalargepercentageofnatural,roundedsand.Natural,roundedsandsveryrarelyhaveFAAvaluesgreaterthan45.Therefore,itwasdeemedunnecessarytoevaluateHRZ

    gradationswithfineaggregateshavingFAAvaluesgreaterthan45.Superpavemixdesignswereconductedonall80factor-level

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    PercentPassin

    %

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    combinations.Forthosemixesthatmetallvolumetriccriteria,performancetestingwasconducted.

    Part2WorkPlan

    TheworkplanforPart2wasverysimilartothatofPart1withtwomajordifferences:1)fewerfactor-levelcombinationsand2)two differentcompactiveefforts.Factor-levelcombinationsincludedwere

    onecoarseaggregate(granite),three9.5mmNMASgradations(BRZ,

    TRZ,andCRZ),andtwocompactiveefforts.TheBRZgradationwas includedasthecontrolgradation.ForPart2,thetwocompactiveefforts

    wereequaltothemediumandveryhightrafficlevels(N design=75and

    125gyrations,respectively).BaseduponthePart1mixdesigndata, sevenfineaggregateswereinvestigatedinPart2.Forthelower

    compactiveeffort(Ndesign=75),mixdesignswereconductedforFA-2,FA-3,FA-4,FA-6,FA-7,andFA-10.Forthehighercompactiveeffort

    (Ndesign=125),mixdesignswereconductedforFA-4,FA-7,FA-9,andFA-10.SimilartoPart1,FA-10wasonlyusedwiththeHRZgradation.

    Mixdesignswereconductedforallcombinationsoffineaggregate,gradation,andcompactiveeffort.Performancetestingwasthenaccomplishedonthosemixturesmeetingallvolumetricrequirements.

    Forthelowercompactiveeffortexperiment(N design=75),humpedgradations(HRZ)wereincludedforthefineaggregateshavingaFAA

    valueless45.0(FA-2andFA-3).Part3WorkPlan

    TheprimaryobjectiveofPart3wastoextendthePart1andPart2researchresultsto19.0mmNMASgradations.DuringParts1and2,only9.5mmNMASgradationswereused.TwocompactiveeffortswereutilizedinPart3:75and100gyrations.Withinthelower

    compactiveeffortexperiment(Ndesign=75),agravelcoarseaggregatewasutilizedbecausepreliminarytestingindicatedthatmixescontainingthegravelcoarseaggregateshouldpreventmixtureswithexcessive

    VMA(asseenatNdesign=75duringPart2).Fivefineaggregateswere usedincluding:FA-2,FA-3,FA-4,FA-6,andFA-7.Thesefine

    aggregatesareidenticaltothoseusedduringthePart2workatNdesign=75.Threegradationswereincluded:BRZ(belowtherestrictedzone),

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    Part3Gradations

    ControlPoints ResrictedZone BRZ ARZ TRZ Hump Crossover

    1009080706050403020100

    0.075 0.300.60 1.18 2.36 4.75 9.5 12.5 19.0 25.0SieveSize,mm

    Figure3:Part3Gradations

    TRZ(throughtherestrictedzone),andARZ(abovetherestrictedzone).

    ThesegradationsareillustratedinFigure3.ThesameasphaltbinderwasusedinPart3asinParts1and2.Mixdesignswereconductedforthe

    HRZ(humpedthroughtherestrictedzone)forFA-2andFA-3(FAAvalueslessthan45.0).

    Withinthehighercompactiveeffortexperiment(Ndesign=100),agranitecoarseaggregatewasusedwithfivefineaggregates:FA-2,FA- 4,FA-6,FA-7,andFA-9.Again,theBRZ,TRZ,andARZgradations

    wereinvestigated.Forbothcompactiveeffortexperiments,mixdesignsand

    performancetestingusingFA-10andtheHRZgradationwereconducted.SimilartoParts1and2,thisinformationshouldprovidea

    "worstcase"baseline.Mixturesmeetingallvolumetriccriteriawereusedforperformance

    testing.ForPart3,onlytheAsphaltPavementAnalyzer(APA)was

    usedasaperformancetest.

    ResponseVariables

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    PercentPassin

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    Theperformanceofmixeswithvariousfactor-levelcombinations meetingSuperpavevolumetricrequirementswereevaluatedonthebasis

    ofperformance-relatedmechanicaltests.Sincetheprimarypurposeof

    therestrictedzoneistoavoidrut-pronemixes,themixesinthisstudy wereevaluatedfortheirruttingpotential.Thiswasaccomplishedbytwo

    differenttypesoftests:empiricalandfundamental.Fortheempiricaltest, theAsphaltPavementAnalyzer(APA)wasused.TheSuperpavesheartester(SST)andtherepeatedloadconfinedcreep(RLCC)testwere

    utilizedasfundamentaltests.Threetestswereincludedtoensureasatisfactoryconclusionofthis

    study.Itwasnotexpectedthatallthreepermanentdeformationtests (oneempiricalandtwofundamental)wouldprovideexactlysimilarresults.Iftheydid,onemixvalidationtestwouldbesufficient.However,

    allthreetestsmightnotbeequallysensitivetochangesingradationandFAAvalues.TheirrelativesensitivitytochangesingradationandFAAvalueswouldbeevidentfromthetestdata.Thetestwhichismostsensitivetothesetwoimportantfactorsofthisresearchprojectwillbe

    consideredmostrelevantandsignificant.

    AsphaltPavementAnalyzer(APA)

    TheAsphaltPavementAnalyzer(APA)isanautomated,new generationofGeorgiaLoadWheelTester(GLWT).TheAPAfeaturescontrollablewheelloadandcontactpressure,adjustabletemperature

    insidethetestchamber,andthecapabilitytotestthesampleseitherwhiletheyaredryorsubmergedinwater.TheAPAtestwasconducteddryto

    8,000cyclesandrutdepthsweremeasuredcontinuously.TheAPAcan

    testthreepairsofgyratorycompactedspecimensof75mmheight.TestingwiththeAPAwasconductedat64C.Theairvoidcontentof

    thedifferentmixtureswas6.00.5percent.Themixturewasaged2hoursatthecompactiontemperaturepriortocompacting.Hosepressureandwheelloadwere690kPaand445N(100psiand100lb),

    respectively.

    SuperpaveShearTester-SST(AASHTOTP7-94)

    TheSuperpavesheartester(SST)simulates,amongotherthings,the

    comparativelyhighshearstressesthatexistnearthepavementsurfaceat theedgeofvehicletires;stressesthatleadtothelateralandvertical

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    deformationsassociatedwithpermanentdeformationinsurfacelayers. TheRepeatedShearatConstantHeightTest(AASHTOTP7,ProcedureF)wasselectedtoassessthepermanentdeformationresponsecharacteristicsofthemixtures.Thistestoperatesbyapplyingrepeatedshearloadpulsestoanasphaltmixturespecimen.Asthe

    specimenisbeingsheared,theconstantheightpreventsspecimen dilation,therebypromotingtheaccumulationofpermanentshearstrain.

    AllspecimensforSSTtestingwerefabricatedat3.00.5percentairvoidsandtestedat50C.Thistesttemperaturewasselectedbecauseitisrepresentativeofeffectivetemperatureforpermanentdeformation

    (Teff(PD))asusedinSSTprotocolfortheSoutheastandisbelievedtobecriticalforinducingruttinginHMApavements.Priortocompaction,themixturewasagedfor4hoursat135C.

    RepeatedLoadConfinedCreepTest(RLCC)

    Repeatedloadconfinedcreeptestisconsideredtobeafundamental

    experimentalmethodtocharacterizetheruttingpotentialofHMA,sincefundamentalcreepprinciplescanbeappliedtodeformationofviscoelasticmixes.AMaterialTestingSystem(MTS)wasusedto

    conductthistest.Adeviatorstressalongwithaconfiningstressis repetitivelyappliedonaHMAsamplefor1hour,with0.1secondloaddurationand0.9secondrestperiodpercycle.Aftertheonehourtest,theloadisremovedandthereboundmeasuredfor15minutes.Thestrain

    observedattheendofthisperiodisreportedasthepermanentstrain. Thepermanentstrainindicatestheruttingpotentialofamix.Thetarget airvoidcontentformixturestestedbytheRLCCtestwas4.00.5percent.Priortocompaction,themixturewasagedfor4hoursat135C.Thetesttemperaturewas60C.Testloadingsconsistedofan138kPa

    (20psi)confiningpressureandan827kPa(120psi)normalpressure.

    TESTRESULTS,ANALYSIS,ANDCONCLUSIONS

    Asmentionedearlier,theexperimentalplanwasdividedintothree parts.ExperimentsinParts2and3wereguidedbytheresultsofPart1.

    Thissectionisdividedintothreesubsections.Eachsubsectionprovides

    testresults,analysis,anddecisionsmadeforsubsequentparts.

    Part1TestResultsandAnalysis

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    Mixdesignsfor9.5mmnominalmaximumaggregatesize(NMAS)mixeswereconductedfor80factor-levelcombinationsduringPart1.As

    mentionedearlier,thecompactiveeffortusedinPart1correspondedtoa designtrafficlevelof3-30millionESALs(Ndesign=100gyrations).TablesA.1throughA.10intheappendixprovidevolumetricdataforeachofthe factor-levelcombinationsatoptimumasphaltcontentandarearrangedin

    orderofincreasingFAAvalues.Ofthe80mixesdesigned,onlyninemixesmetallvolumetric(VMA,

    VFA,and%Gmm@Nini)andFAAcriteria.Ofthemixesnotmeetingcriteria,22didnotmeetVMA,13didnotmeetVFA,sixdidnotmeet

    %Gmm@Nini,28didnotmeetVMAand%Gmm@Nini,onedidnotmeet

    %Gmm@NiniandVFA,andonedidnotmeetVMAandVFA.Based uponthesestatistics,thecriteriaforVMAand/or%G mm@Niniexcluded

    themostmixes.Asecondarygoalofthisresearchwastoevaluatetheeffectofmix

    constituentpropertiesonthevolumetricsofthe80designedmixes. Volumetricpropertiesconsideredincludeairvoids,VMA,VFA,

    %Gmm@Nini,and%Gmm@Nmaximum.Airvoidswerekeptconstantat4percentasthisvoidleveldefinesoptimumasphaltcontent,soairvoidswerenotanalyzed.VFAisafunctionofVMAandairvoidsandnomix

    failed%Gmm@Nmaximum,soneitherwereincluded.Therefore,onlyVMA

    and%Gmm@Niniwereanalyzed.Thefirststepinthisanalysiswastoconductananalysisofvariance

    (ANOVA)todeterminetheeffectofcoarseaggregate,fineaggregate,

    andgradationonVMAand%[email protected],thecalculationoftheF-statisticshadtobesomewhatmodified.Thiswas becauseonlyoneresponsewasobtainedforeachfactor-level combination(e.g.,therewasonlyoneVMAforeachmix).Tocalculate theF-statistic,thedegreesoffreedomassociatedwiththeinteractions betweentheexperimentfactorsweresacrificed.Thissacrificeofdegreesoffreedomfortheinteractionsprovidedthenecessarymean squaresoferrortocalculatetheF-statisticwithoutsacrificingtheresults

    oftheANOVA.ResultsoftheANOVAconductedtoevaluatethesignificanceofthe

    experiment'smainfactorsispresentedinTable4.ThistableshowsthatallthreemainfactorssignificantlyaffectVMA.BasedupontheF-statistics,thecoarseaggregatehadthegreatesteffectonVMA(largest

    F-statistic)followedbyfineaggregateandgradation,respectively.Figure4illustratestherelativeeffectofcoarseaggregateand

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    gradationonVMA.EachbaronthisfigurerepresentstheaverageVMAformixeshavingthesamecoarseaggregateandgradationtype. Therefore,eachbaristheaverageVMAforallfineaggregates.Thisfiguresuggeststhatmixescontainingthemoreangularcoarseaggregate (granite)yieldedcollectivelyhigherVMAvaluesthanmixescontaining

    thecrushedgravelfineaggregate.Thiswastrueforeachgradation.

    Figure4showsthattheARZandCRZgradationstendedtoprovide

    higherVMAvaluesandtheHRZandTRZprovidedthelowestVMA values.RecallthattheHRZgradationwasonlycombinedwithfine

    aggregateshavinganFAAof45orlower.EvaluationofTablesA.2

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    Table4:ResultsofANOVAtoDetermineSignificanceofMain FactorsonVMA

    Source DF F P

    CoarseAggregate 1 156.40 0.000

    FineAggregate 8 110.85 0.000

    Gradation 4 13.99 0.000

    EffectofGradationonVoidsinMineralAggregate(Part1)

    GraniteGravel16.0

    15.0

    15.3

    15.1

    15.4

    BarsrepresentaverageVMAforallmixescontainingtherepresentativegradationandcoarseaggregate.

    14.0

    13.0

    12.0

    11.0

    10.0

    14.3 14.0

    14.1

    14.4

    13.3

    14.5

    13.4

    ARZ BRZ CRZ HRZ TRZGradation

    Figure4:EffectofGradationonVoidsinMineralAggregate

    throughA.4indicatethattheHRZgradationprovidedhigherVMA values(averageof14.4percentforgraniteand13.3percentforgravel

    coarseaggregates,respectively)thandidtheTRZgradation(averageof 13.8percentforgraniteand12.9percentforgravelcoarseaggregate,

    respectively).SincetheTRZgradationgenerallyprovidedthelowestVMAvalues,itappearsthatthemaximumdensitylinedefinedwithinthe

    Superpavemixdesignsystemfor9.5mmNMASgradationsisintherelativelycorrectlocation.

    TheeffectoffineaggregateontheVMAvalueswasevaluatedbycorrelatingVMAtoFAA.Detailedanalysesaregivenelsewhere(3).

    18

    VoidsinMineralA

    reate%

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    TherelationshipbetweenVMAandFAAwerefoundtobepoorasR 2valuesweretypicallybelow0.25.Althoughtherewasnosignificanceto therelationships,theredidappeartobeatrendthatiscommontoall

    relationships:increasingVMAvalueswithincreasingFAAvalues.ResultsoftheANOVAconductedtoevaluatethesignificanceof

    coarseaggregate,fineaggregate,andgradationon%G [email protected]

    significantlyaffect%Gmm@Nini,similartotheVMAanalysis.BasedupontheF-statistics,thefineaggregatehadthegreatesteffect,followed bygradationandcoarseaggregate,respectively.

    Table5:ResultsofANOVAtoDetermineSignificanceofMain

    Factorson%Gmm@Ninitial

    Source DF F P

    CoarseAggregate 1 7.89 0.007

    FineAggregate 8 101.85 0.000

    Gradation 4 38.31 0.000

    Figure5illustratestheeffectofcoarseaggregateandgradationon

    %[email protected],theeffectofcoarseaggregate typeseemstobeminimal(thoughsignificant).Thisfiguresuggeststhat

    theBRZgradationprovidedthelowest%[email protected]

    gradationhadsimilarbutslightlyhigher%[email protected]

    suggeststhattheHRZgradationprovidedthehighest%G [email protected],similartotheVMAanalysis,thisconclusionwouldbemisleading.Forthethreefineaggregatesinwhichbothgradationswere

    utilized,the%Gmm@Niniaveraged91.0percentfortheHRZgradationand90.7percentfortheTRZgradation.Therefore,bothappearsimilar andsuggestthattheARZgradationactuallyprovidedthehighest

    %Gmm@Ninivalues.

    Theeffectoffineaggregateon%Gmm@NiniisillustratedinFigures6 and7formixescontaininggraniteandgravelcoarseaggregate,respectively.ThesefiguresillustratetherelationshipbetweenFAAand

    %[email protected]

    valuesindicateastrongerrelationshipbetweenFAAand%Gmm@NinithanforFAAandVMA.Table6presentstheF-statisticsandprobabilitiesforeachregressionshowninFigure6and7.

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    EffectofGradationon%Gmm@Ninitial

    (Part1)93.092.091.090.0

    Barsrepresentaverage%Gmm@Niniforallmixescontainingtherepresentativegradationandcoarseaggregate.

    89.489.5

    Granite

    91.091.0

    Gravel

    89.088.087.086.0

    85.084.083.0

    87.3

    87.9

    88.188.2

    88.5

    88.9

    ARZ BRZ CRZ HRZ TRZGradation

    Figure5:EffectofGradationon%Gmm@Ninitial(Part1)

    Table6:RegressionStatisticsforFAAvs.%G mm@NinitialRelationships

    Gradation Granite Gravel

    F-statistic p-value F-statistic p-value

    ARZ 10.98 0.013 10.96 0.013

    BRZ 14.76 0.006 7.75 0.027

    CRZ 17.76 0.004 19.31 0.003

    HRZ 10.89 0.081 26.88 0.035

    TRZ 10.97 0.013 8.53 0.022

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    EffectofFAAon%Gmm@Ninitial(GraniteCoarseAggregate)92

    91

    90

    89

    88

    8786

    8584

    R2=0.8448

    HRZARZ

    BR

    ZCR

    Z

    HR

    Z

    TRZ

    R2=0.7173CRZ

    R2=0.6105

    TRZ

    R2=0.6782BRZ

    R2=0.6106ARZ

    36373839404142434445464748495051525354

    FineAggregateAngularity,%

    Figure6:EffectofFineAggregateAngularityon%Gmm@Ninitial(GraniteCoarseAggregate)

    TheregressionstatisticsinTable6suggestasignificantrelationship

    betweenFAAand%[email protected]

    ofFAAledtodecreasingvaluesof%[email protected],noneofthemixeshavinganFAAvalueof45orlowermetthe%G mm@Ninirequirementof89percentmaximum.Thiswastrueforbothcoarseaggregates.Overall,itappearsthathigherFAAvaluescontributetostrongeraggregateskeleton(intermsofmoreresistancetocompaction)

    atinitialcompactionlevels.AnotherinterestingobservationaboutthedatainTablesA.1through

    A.10wasthatnoneofthemixesfailedthe%Gmm@Nmaximumrequirement

    of98percentmaximum.ThiswastrueevenfortheworstcaseFA-10mixeswithahumpedgradation.Thisraisesthequestionwhetherthe

    Nmaximumrequirementisnecessaryorifthelimitof98percentneedstobechanged.

    Aftercompletionofallmixdesigns,performancetestingwasconducted.PerformancetestingincludedtheAsphaltPavement Analyzer(APA),RepeatedShearatConstantHeight(RSCH)withthe

    21

    mm

    initial

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    SuperpaveShearTester,andtheRepeatedLoadConfinedCreep(RLCC)test.It

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    EffectofFAAon%Gmm@Ninitial(GravelCoarseAggregate)92

    91

    90

    89

    88

    87

    86

    8584

    36

    R2=0.9307

    HRZ

    AR

    Z

    BR

    ZCR

    Z

    HR

    Z

    TRZ

    38

    R2=0.5256BRZ

    40

    42

    R2=0.7339

    CRZ

    44

    46

    R2=0.5493

    TRZ

    48

    R2=0.6103ARZ50

    52

    54

    FineAggregateAngularity,%

    Figure7:EffectofFineAggregateAngularityon%Gmm@Ninitial

    (CrushedGravelCoarseAggregate) wasintendedtoconductperformancetestingonlyonmixesthatmetall volumetriccriteria.However,somemixesnotmeetingVFArequirementswereperformancetested.ThisVFAexceptionwasmade becauseofcurrentSuperpaveVMArequirementsfor9.5mmNMASmixtures.Optimumasphaltcontentisdefinedastheasphaltcontentthat

    provides4.0percentairvoids.For9.5mmNMASmixes,theminimum VMAallowedis15.0percent.AtaVMAof15.0percentandairvoid

    contentof4.0percent,VFAisequalto73.3percent.TheSuperpave requirementsforVFArangefrom65.0to75.0percent.ThisVFArange

    effectivelylimitsVMAtoamaximumof16.0percentasairvoidsaresetat4.0percentatmixdesign.Therefore,onlya1.0percentrangeof

    VMAisallowedbytheSuperpavemixdesignrequirements. Theexceptionutilizedinthisstudywasbasedonthefindingsofthe

    WesTrackForensicTeam(7).ItsreportrecommendedthatVMAberestrictedtonomorethan2.0percentabovetheminimumvalue. Therefore,besidesmixesmeetingallvolumetricrequirements,performancetestingwasalsoconductedonmixturesfailingVFA(above

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    75.0percent)butwithVMAvaluesbeloworequalto17.0percent.This providedanallowableVFArangeinthisstudyof73.3to76.5percent.

    Anotherexceptionwastoconductperformancetestingonmixtures containingFA-6(alimestonefineaggregate)andgranitecoarseaggregate(allgradations)eventhoughthesecombinationsdidnotmeetVMA.Thesemixeswereincludedbecausenoneofthemixturesmeetingallvolumetriccriteria(andthoseincludedwiththeVFAexception)containedalimestonefineaggregate,whichisoneofthemostcommon

    aggregatesintheU.S.Therefore,theFA-6/granitemixeswereincluded

    forinformationalpurposesonly.ThefineaggregateFA-10withaverylowFAAvalueof38.6was

    usedwithbothgraniteandgravelcoarseaggregatestoprovideahumped gradationviolatingtherestrictedzone(HRZ).Thesetwomixesdidnot

    meettheSuperpaverequirementsforFAA,VMA,orN initial.However,thesemixeswereperformancetestedtoobtainabaseline,worstcasescenario.

    ResultsofPart1performancetestingarealsopresentedinTables A.1throughA.10givenintheappendix.ResultsfortheAPAarepresentedasthemanuallymeasuredrutdepthafter8,000cycles.FortheRSCHtest,resultsarepresentedasthetotal(plastic)strainafter5,000 cycles,expressedasapercentage.ResultsfortheRepeatedLoad

    ConfinedCreep(RLCC)testarepresentedasthepermanentstrainmeasuredafter3,600loadrepetitions(appliedinonehour)anda15

    minutereboundtime,againexpressedasapercentage.

    Figure8illustratestheresultsofAPAtestingintheformofabarchart.Resultsareshownforthe24mixesthat(a)metallvolumetric criteria,(b)mettheVFAexception,(c)weremadewithFA-6limestone,

    or(d)wasaworst-casescenario(FA-10).DatawithinFigure8areclassifiedbywhetherthemixturehasa

    gradationthatviolatestherestrictedzoneornot.Solidblackbarsdepict mixeshavinggradationsviolatingtherestrictedzone,whilelightgraybars

    representmixeshavinggradationsthatdonotviolatetherestrictedzone.Ascanbeseenfromthefigure,thesamecombinationofcoarseaggregateandgradationwerenottestedforallfineaggregates.

    Therefore,performingananalysisofvariancewasnotpossible.

    Duncan'sMultipleRangeTests(DMRT)wereusedtorankthe

    performanceofmixeshavingidenticalcoarseaggregateandfineaggregate(e.g.,granite/FA-4).Thisanalysisprovidedacomparison betweengradationsforagivencoarseaggregate/fineaggregate

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    combinationtodetermineifgradationsviolatingtherestrictedzoneperformeddifferentlythangradationsresidingoutsidetherestrictedzone.

    12.00

    LettersrepresentresultsofDuncan'sMultipleRangeTestforeachcoarse/fineaggregate

    ViolatesRZControl

    10.00 combination. A

    8.00

    6.00

    4.00

    2.000.00

    ABABB

    A

    B

    A

    A AA BB

    AB

    A

    B

    A A

    A

    A

    B

    ABAB

    Gr.Gv. Gran. Gran. Grav. Gran. Grav. Gran. Grav.FA-10 FA-6 FA-7 FA-4 FA-9

    FAA=38.6 FAA=46.5 FAA=48.9 FAA=49.7 FAA=50.1Nat.Sand Limestone Granite Sandstone Traprock

    Figure8:APARutTestData(Part1)Figure8showstheresultsoftheDMRTrankingsasA,AB,andB.

    Thereisnostatisticallysignificantdifference( "=0.05)inperformanceiftwogradationswithinacoarseaggregate/fineaggregatecombination

    havethesameletterranking. Figure8showsthatallthreemainfactors(coarseaggregate,fine

    aggregate,andgradationshape)appeartoaffectthemeasuredAPArut

    depths.Collectively,wherecomparisonsarepossible,mixescontainingthemoreangulargranitecoarseaggregatetendedtohavelowerrut

    depths.Thefineaggregatetypealsoaffectedthemeasuredrutdepths.The

    FA-10mixescontaininggravelcoarseaggregatewastheleastrut resistant.Alsoaswouldbeexpected,mixescontainingFA-6(limestone)wererutresistant.RecallthatthesefourFA-6mixeswereincludedfor

    informationalpurposesonly,sinceallfailedVMArequirements(low). SinceeachmixhadlowVMA,allfourmixeswereunder-asphaltedandthereforerutresistant.However,theFA-6mixesthatviolatedthe restrictedzonecriteria(TRZandCRZ)didperformsimilarlytothemixes

    25

    RutDeth,mm

    HRZ

    HRZ

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    TRZ

    BRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    ARZ

    TRZ

    BRZ

    ARZ

    TRZ

    CRZ

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    notviolatingtherestrictedzone(BRZandARZ). Inallbutonecase(FA-7/Granitemixes)ofthesevencoarse

    aggregate/fineaggregatecombinationstested,themixeshavinggradationsthatviolatetherestrictedzoneperformedsimilarlyorbetterthanthemixeshavinggradationsthatdidnotviolatetherestrictedzone.Inthisonecase,therutdepthsforbothFA-7/Granite/BRZandFA- 7/Granite/TRZwerebothlessthan6mm.BaseduponthesePart1APA data,itappearsthattherestrictedzoneispracticallyredundantasa requirementtoensureadequaterutresistanceifthemixmeetsall

    SuperpavevolumetricandFAAcriteria.NomeaningfulrelationshipbetweenFAAvaluesandAPArutdepth

    wasobtained,probablybecausetheFAAvaluesofthemixes(whichmet

    volumetricrequirements)onlyrangedfrom48.9to50.1.

    Figure9illustratestheresultsoftheRepeatedLoadConfinedCreep(RLCC)test.Resultsarepresentedaspermanentstrain,inpercent. Mixturesexceedingabout10-13percentpermanentstrainhavegenerally

    shownthepotentialforrutting(8).SimilartotheAPAresults,themixes

    containingFA-10hadtheleastresistancetopermanentdeformation.

    TheseFA-10mixeshadconsiderablyhigherpermanentstrainvalueswhencomparedtotheothermixes.TheFA-6limestonemixes collectivelyhadthelowestpermanentstrainvalues,similartotheAPArutdepths.Againthiswaslikelyduetothelowasphaltcontentsinthese

    mixes(lowVMA).

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    SimilartotheAPAanalysis,DMRTrankingswereconductedoneachcombinationofcoarseaggregate/fineaggregatetoisolatetheeffect ofgradationandarepresentedonFigure9.Inallbutonecase(FA- 9/Granite)ofthesevencoarseaggregate/fineaggregatecombinationstested,themixeshavinggradationsviolatingtherestrictedzoneperformedaswellorbetterthanthemixeshavinggradationscomplying withtherestrictedzonerequirement.Closeinspectionoftheone exception(FA-9/Granite)showsthatbothmixesARZandTRZhaveverylowpermanentstrainvaluesand,therefore,canbeconsideredrut

    resistant.TheRLCCdataappearstoconfirmtheAPAconclusionthat therestrictedzonerequirementisnotneededwhentheSuperpave

    volumetricandFAAcriteriaaremet.

    Figure10presentstheRSCHtestdata.Resultsinthisfigureare shownasplasticstrain,expressedasapercentage.Initialobservationof

    45.0

    Lettersrepresentresultsof

    40.035.0

    Duncan'sMultipleRangeTestforeachcoarse/fineaggregatecombination.

    ViolatesRZControl

    30.02.525.020.02.015.0

    A

    ViolatesRZControl

    AA

    A

    A

    B

    B

    A

    10.01.55.00.01.0

    AAA

    BBA

    A

    A

    AAA

    A

    A

    AA

    AA

    AAAA

    AA

    AA

    B

    A

    B

    BA

    AA

    A B

    A B

    Gr.Gv. Gran. Gran. Grav. Gran. Grav. Gran. Grav.FA-10 FA-6 FA-7 FA-4 FA-9

    FAA=38.6 FAA=46.5 FAA=48.9 FAA=49.7 FAA=50.1Nat.Sand Limestone Granite Sandstone Traprock

    0.5

    Figure9:RepeatedLoadConfinedCreepTestData(Part1)

    0.0

    Gr.Gv. Granite Granite Gravel Granite Gravel Granite GravelFA-10 FA-6 FA-7 FA-4 FA-9FAA=38.6 FAA=46.5 FAA=48.9 FAA=49.7 FAA=50.1Nat.Sand Limestone Granite Sandstone Traprock

    Figure10:RSCHTestData(Part1)

    27

    PermanentStrain,

    PlasticStrain,%

    HRZ

    HRZ

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    TRZ

    BRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    ARZ

    TRZ

    BRZ

    ARZ

    TRZ

    CRZ

    HRZ

    HRZ

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    TRZ

    BRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    ARZ

    TRZ

    BRZ

    ARZ

    TRZ

    CRZ

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    Figure10indicateslittlevariationinthetestresults,eventheworstcase FA-10mixesdidnothavehighplasticstrainvalues.Alltestresultswere

    below2.5percentplasticstrain,whichhistoricallysuggestsadequaterut resistance.SimilartotheAPAandRLCCtestdata,DMRTrankingsweredeterminedforeachfineaggregate/coarseaggregatecombination andareshownonthefigure.Theserankingsalsoshowthatlittle variationintestresultswereexhibited.ExceptfortheFA-9/Gravel combination,allcombinationshadsimilarDMRTrankings.Thissuggests

    thattheRSCHtestwasnotsensitiveenoughtoidentifysmallchangesingradationorasphaltcontent,possiblybecauseoftestvariability.Three replicateswereusedinthisstudy.Recentresearch(9)hassuggestedthe

    useoffivereplicates,discardingtheminimumandmaximumvaluesand

    averagingthemiddlethreevaluestoimprovethereliabilityoftheRSCH

    test.Part2TestResultsandAnalysis

    SimilartoPart1,Part2involved9.5mmNMASgradations,butincludedtwocompactiveeffortsdifferentthanthatusedinPart1.The

    twocompactiveeffortscorrespondedto0.3-3millionESALs(N design=75

    gyrations)andmorethan30.0millionESALs(Ndesign=125gyrations).Onlythreegradationswereusedinallmixes:BRZ(belowrestrictedzone),TRZ(throughrestrictedzone),andCRZ(cross-overinrestricted

    zone).OnlythegranitecoarseaggregatewasusedinPart2.DuringPart

    1,gravelcoarseaggregateproducedmixeswithlowVMAvalues.SixfineaggregatesFA-10,FA-2,FA-3,FA-6,FA-7,andFA-4(inincreasingorderofFAAvalues)wereusedinmixesdesignedwith

    Ndesignof75gyrations.TablesA.11throughA.16intheappendixgiveoptimummixdesigndataformixeswiththesefineaggregates, respectively.Fourfineaggregates(FA-10,FA-7,FA-4andFA-9)were

    usedinmixescompactedwithNdesignof125gyrations.TablesA.17 throughA.20intheappendixgiveoptimummixdesigndataforthesefineaggregates,respectively.Fineaggregateswhichhadhighpotentialof

    meetingtheminimumVMArequirements(basedonmixdesigndata obtainedinPart1)wereselectedforPart2.Alimestonefineaggregate

    (FA-6)wasincludedbecauselimestoneiswidelyusedintheU.S.SinceeachofthemixesstudiedinPart2containedthesamecoarse

    aggregate,factorsevaluatedweredesigncompactiveeffort,fine aggregatetype(FAA),andgradationshape.Similartotheanalyses

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    Figure11illustratestheresultsoftheAPAtestingconductedonPart 2mixesdesignedat75gyrationsthatmetallvolumetriccriteria(includingVFAexceptionusedinPart1).Initialobservationofthisfiguresuggests thatangularityandsurfacetextureofthefineaggregate(FAA)hasa significanteffectonmeasuredrutdepths.Thosemixescontainingfine

    aggregateswithFAAvaluesabove46(FA-4,FA-6,andFA-7)allhadsignificantlylowerrutdepthsthanthemixeswithfineaggregateshavingFAAvaluesbelow46(FA-10,FA-2,andFA-3).Alsouponinitialobservation,thetwoFA-3gradations(BRZandCRZ)thatmetvolumetricrequirementshadrutdepthsthatwereslightlyhigherthanthe

    worst-casebaselineFA-10mix.Fromarestrictedzonestandpoint,there wasnostatisticaldifferencebasedonDMRTrankingsinrutdepths betweentheFA-3mixthatviolatedtherestrictedzone(CRZ)andthe

    controlgradation(BRZ).TheonlyothercombinationinwhichacomparisoncouldbemadebetweenagradationviolatingtherestrictedzoneandacontrolgradationwasforFA-6.Again,therewasno statisticaldifferencebasedonDMRTrankingsinrutdepthsbetweenthe twomixes(BRZandCRZ).FA-2,FA-4,andFA-7hadonlyone

    20

    A

    18 A1614

    12108 A A6420

    HRZ TRZ BRZ CRZ TRZ BRZ CRZ TRZFA-10 FA-2 FA-3 FA-4 FA-6 FA-7

    FAA=38.6 FAA=42.6 FAA=44.1 FAA=49.7 FAA=46.9 FAA=48.9Nat.Sand Nat.Sand Nat.Sand Sandstone Limestone Granite

    Figure11:ResultsofAPATestingonMixesDesignedWith75

    GyrationsforPart2

    30

    RutDeth

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    gradation(mix)thatmetvolumetricrequirements(includingtheVFAexception).OthergradationsforthesefineaggregateshadVMAvalues

    inexcessof17.0percent.WithintheSuperpavemixdesignsystem,fineaggregatesusedin

    mixesdesignedat75gyrationshavearequirementforFAAof40percentminimum.ThedataillustratedinFigure11suggeststhatmixeshavingfineaggregateswithFAAvaluesbelow46tendtohavemorepotentialforrutting.However,fromthestandpointoftherestrictedzone

    theredoesnotseemtobeaninteractionbetweentheeffectofFAAand gradationspassingthroughtherestrictedzone.ThisisshownbythedataforFA-3inwhichtheBRZandCRZgradationsbothhavesimilarrutdepths.Therefore,itcanbesurmisedthatevenforthislowercompactiveefforttherestrictedzoneisnotneededtoensurearutresistantmixture.

    Infact,thedataappearstoindicatetheneedforalaboratory"proof"testtobeusedondesignedmixes.

    Figure12illustratestheAPAresultsofPart2mixesdesignedwith

    125gyrations.Thisfigureshowslittledifferenceinrutdepthsbetween anyoftheexperimentalmixes(FA-4,FA-7,andFA-9mixes).FA-10

    hadthehighestrutdepth,asexpected,atapproximately11mm.The remainingmixesallhadrutdepthsofapproximately8mm.Foreachof

    thefineaggregates(exceptFA-10),sufficientgradationswereavailabletoconductDMRTrankingstocomparethegradationsviolatingthe restrictedzone(TRZandCRZ)andthecontrolgradation(BRZ).Forallthreefineaggregates(FA-4,FA-7,andFA-9),therewasnostatistical

    differencebetweenthedifferentgradations.SimilartothePart1APA data,Figure12suggeststhattherestrictedzoneispracticallyredundant asarequirementtoensureadequaterutresistanceifthemixmeetsall

    SuperpavevolumetricandFAAcriteria.Figure13illustratestheresultsofRLCCtestingconductedonPart2

    mixesdesignedwith75gyrations.ThisfiguredoesnotshowthetwoFA-

    3mixeswhichfailedpriorto3,600loadrepetitions(TableA.13).TheresultsillustratedinFigure13aresimilartotheAPAresults

    showninFigure11inthatthemixescontainingfineaggregateswith FAAvalueslessthan46(FA-10,FA-2,andFA-3)allshowed

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    14

    12

    10

    8

    6

    4

    2

    0

    HRZ

    A

    BRZ

    A

    TRZ

    A

    CRZ

    A

    BRZ

    A

    TRZ

    A

    CRZ

    A

    BRZ

    A

    TRZ

    FA-10FAA=38.6Nat.Sand

    FA-4FAA=49.7Sandstone

    FA-7FAA=48.9Granite

    FA-9FAA=50.1Diabase

    Figure12:ResultsofAPATestingonMixesDesigned

    With125GyrationsforPart2

    40353025

    Threereplicatesofbothgradationsfailed

    20 priortothecompletionof3,600loadrepetitions.

    15

    10 A

    A

    50

    HRZ TRZ BRZ CRZ TRZ BRZ CRZ TRZFA-10 FA-2 FA-3 FA-4 FA-6 FA-7

    FAA=38.6 FAA=42.6 FAA=44.1 FAA=49.7 FAA=46.9 FAA=48.9Nat.Sand Nat.Sand Nat.Sand Sandstone Limestone Granite

    Figure13:ResultsofRLCCTestingonMixes

    DesignedWith75GyrationsforPart2

    32

    RutDeth,mm

    PermanentStrain,%

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    significantlylesspermanentdeformationresistancethanthemixescontainingfineaggregateswithFAAvaluesabove46(FA-4,FA-6,and

    FA-7).Onlyonefineaggregatehadmixesinwhichgradationsviolating

    therestrictedzoneandacontrolgradationcouldbecompared(FA-6). Forthisfineaggregate,theDMRTrankingsindicatethatbothgradations

    havesimilarrutdepths.BaseduponboththeAPAandRLCCperformancedataformixes

    designedwith75gyrations,itappearsthatthevolumetricandFAAcriteriaalonedonotensurearutresistantmixture.However,gradations

    passingthroughtherestrictedzonedonotshowmorepropensitytorut

    thangradationsresidingoutsidetherestrictedzone.ResultsofRLCCperformancetestingonPart2mixesdesignedwith

    125gyrationsareillustratedinFigure14.SimilartotheN design=125Part2

    APAtesting,allofthemixesexcepttheFA-10mixhadsomewhatsimilarlaboratoryperformance.TheworstcaseFA-10mixhad significantlyhigherstrainvaluesthantheothereightmixestested.SufficientdatawasavailabletoconductaDMRTrankingwithintheFA-4,FA-7,andFA-9mixes.ResultsofthethreeDMRTrankingsindicate

    30252015

    1050

    HRZFA-10

    ABRZ

    A

    TRZFA-4

    ACRZ

    A

    BRZ

    A

    TRZFA-7

    A

    CRZ

    ABRZ

    FA-9

    A

    TRZ

    FAA=38.6Nat.SandFAA=49.7Sandstone

    FAA=48.9Granite FAA=50.1Diabase

    Figure14:ResultsofRLCCTestingonMixesDesignedwith

    125GyrationsforPart2

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    thepermanentstrainvaluesforeachgradation(withagivenfine aggregate)arenotsignificantlydifferent.Interestingly,theCRZgradationdidshowthehighestmagnitudepermanentstrainforboththe FA-4andFA-7datathoughitwasnotsignificantlydifferent.Basedupon

    thesePart2,Ndesign=125performancedata,itappearsthattherestrictedzoneisredundantwiththeSuperpavevolumetricandFAAvalue.

    Figure15illustratestheresultsofRSCHtestingonPart2mixesdesignwith75gyrations.UnlikethePart1RSCHdata(Figure10),there issomevariationintestdatabetweenthemixestested.Similartothe APAandRLCCtestingconductedonmixesdesignedwith75gyrations,themixescontainingfineaggregateswithFAAgreaterthan46(FA-4,

    FA-6,andFA-7)hadsignificantlylessplasticstrainthanthosemixesutilizingfineaggregateswithFAAvalueslessthan46(FA-10,FA-2,and

    FA-3).TheFA-10/HRZ,FA-2/TRZ,andFA-3/CRZmixeshadplasticstrainsapproachingthelimitsmeasurablebytheRSCHtest(approximately8percent).Theotherfourmixes(FA-4/TRZ,FA-6/BRZ,FA-6/CRZ,andFA-7/TRZ)allhadplasticstrainslessthan3percent.

    ThereweresufficientFA-3andFA-6mixestoevaluatethe

    8

    A7

    6

    5

    B4

    A3

    2

    1

    0

    HRZFA-10

    TRZFA-2

    BRZ

    FA-3

    CRZ

    TRZFA-4

    BRZ

    FA-6

    ACRZ

    TRZFA-7

    FAA=38.6 FAA=42.6 FAA=44.1 FAA=49.7 FAA=46.9 FAA=48.9Nat.Sand Nat.Sand Nat.Sand Sandstone Limestone Granite

    Figure15:ResultsofRSCHTestingonMixesDesignedWith

    75GyrationsforPart2

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    restrictedzonewiththeDMRT.Ofthesetwo,FA-3hadsignificant differencesinplasticstrainbetweenthegradationviolatingtherestrictedzone(CRZ)andthegradationresidingoutsidethezone(BRZ).TheplasticstrainfortheFA-3/BRZgradationwasapproximately4percentwhiletheplasticstrainfortheFA-3/CRZgradationwasapproximately7percent.Bothofthesemixeswouldbeconsideredsusceptibleto permanentdeformationbaseduponpreviousresearch.FortheFA-6 combinations(BRZandCRZ),resultsoftheDMRTrankingssuggested

    thattheplasticstrainvaluesweresimilar.SimilartotheAPAandRLCCtesting,theresultsshowninFigure15

    suggestthatvolumetricandFAAcriteriaarenotadequatetoensurerut

    resistantmixeswhentheNdesign=75designcompactiveeffortisutilized. TheAPAandRLCCtestresultsindicatedthatthepotentialforruttingis

    notenhancedwhengradationspassthroughtherestrictedzone. However,basedupontheFA-3RSCHdatatheCRZgradation(which

    violatestherestrictedzone)didshowsignificantlyhigherpotentialfor

    rutting.

    5

    4

    32

    1

    0

    HRZ

    ABRZ

    ATRZ

    A

    CRZ

    A

    BRZ

    A

    TRZ

    A

    CRZ

    A

    BRZ

    A

    TRZ

    FA-10FAA=38.6

    Nat.Sand

    FA-4FAA=49.7

    Sandstone

    FA-7FAA=48.9Granite

    FA-9FAA=50.1Diabase

    Figure16:ResultsofRSCHTestingonMixesDesignedwith

    125GyrationsforPart2

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    ResultsoftheRSCHtestingconductedonPart2mixesdesigned with125gyrationsareillustratedinFigure16.ThedataillustratedinFigure16isverysimilartothatshownforthePart1RSCHdata(Figure

    10)inthatmixescontainingFA-9hadhigherplasticstrainvaluesthandidtheworstcaseFA-10.BesidestheFA-9data,allremainingdataappeartobesimilar(includingFA-10).SufficientmixcombinationswereavailabletoconducttheDMRTrankingsforgradationspreparedwithFA-4,FA-7,andFA-9.Inallinstances,nosignificantdifferenceswere

    shownbetweenthegradations.ThissuggeststhattherestrictedzoneisessentiallyredundantwiththeSuperpavevolumetricandFAAcriteriafor

    thesehightrafficvolumemixes.

    Part3TestsResultsandAnalysis

    Part3wasacontinuationofParts1and2withthedifferencethat

    19.0mmNMASgradationswereusedinsteadof9.5mmNMASgradations.Four19.0mmNMASgradationswereincludedinPart3:

    BRZ,TRZ,HRZ,andARZ.TheBRZ,TRZ,andARZgradationswere usedwithallfineaggregates,whiletheHRZgradationwasincludedonlywithfineaggregateshavingaFAAvaluelessthan45percent.BoththegraniteandgravelcoarseaggregateswereincludedinPart3.Two

    designcompactiveeffortswereused,Ndesign=75and100.DuringParts1and2,anumberofmixeshadexcessiveVFA(above75percentbecause ofexcessiveVMA).Inanefforttoreducethenumberofmixes

    excludedfromperformancetestingduetoexcessiveVFA,mixesdesignedwith75gyrationsutilizedthegravelcoarseaggregatewhilemixesdesignedat100gyrationsutilizedthegranitecoarseaggregate.AlsodifferentinPart3wasthemethodofconductingmixdesigns.In Parts1and2,mixdesignswereconductedonallfactor-level combinations.DuringPart3,foragivencoarseaggregate/fineaggregate combination,mixdesignswerefirstconductedforthegradation(s) violatingtherestrictedzone.Ifthesemixesmetallvolumetriccriteria,

    thenmixdesignswereconductedforthecontrolgradations. Atotalofsixfineaggregateswereinvestigatedforthe75gyration

    designcompactiveeffortandincluded:FA-10,FA-2,FA-3,FA-4,FA-6, andFA-7.ResultsofthesemixdesignsarepresentedinTablesA.21 throughA.26intheappendix.Sixfineaggregateswerealsoinvestigated

    formixesdesignedwith100gyrationsandincluded:FA-10,FA-2,FA-4,FA-6,FA-7,andFA-9.Resultsofthesemixdesignsarepresentedin

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    TablesA.27throughA.32intheappendix.SimilartoParts1and2,the FA-10fineaggregatewasincludedasaworst-casebaselineon

    performance.Ofthefiveexperimentalfineaggregatesusedwiththe75gyration

    designeffort(excludingFA-10),threehadgradationsviolatingtherestrictedzonethatmetvolumetriccriteria(FA-2,FA-4,andFA-7).For

    thetwofineaggregatesnotmeetingvolumetriccriteria(FA-3andFA-6), theVMAvalueswerebelowthe13percentminimum.SimilartotheanalysisinParts1and2,theeffectofgradationonVMAand

    %Gmm@Niniwasevaluatedforthe75gyrationdesigneffortmixes. Includedinthisanalysiswerethefineaggregatesinwhichallgradationswereinvestigated(FA-2,FA-4,andFA-7).Becauseonlythreefineaggregateswereincludedinthisanalysis,nocomparisonsweremade

    betweenVMAor%Gmm@NiniandFAAvalues. Figure17illustratestheeffectofgradationonVMA.ThisfigureshowsthattheBRZgradationprovidedmuchhigherVMAvaluesthandidtheTRZ,ARZ,orHRZ gradations.TheTRZandARZgradationsprovidedsomewhatsimilarVMAs.Figure17suggeststhattheHRZgradationprovidedthelowest

    VMAvalue;however,theHRZgradationwasonlyincludedwithFA-2(FAAlessthan45percent).ForFA-2,theHRZgradationprovided

    approximatelythesameVMA(13.0percent)astheTRZandARZgradations(12.9and12.8percent,respectively).Theseresultsaresimilar

    tothosepresentedinParts1and2.

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    Theeffectofgradationon%Gmm@NiniisillustratedinFigure18. Thisfigureshowsthatasthegradationbecomescoarser,%[email protected]%Gmm@NiniwhiletheARZhadthehighest.ThisisverysimilartoresultsinParts1and2.

    TheHRZgradationdidhaveahigh%Gmm@Ninivalue;however,acomparisonoftheFA-2data(TableA.22)suggeststhattheHRZ

    EffectofGradationonVoidsinMineralAggregate(Part3)

    16.0

    15.0

    14.013.012.011.010.0

    Ndesign=75

    13.3

    TRZ

    13.6

    ARZ

    14.7

    BRZ

    13.0HRZ

    Figure17:EffectofGradationonVoidsinMineralAggregate

    (Ndesign=75),Part3

    38

    VoidsinMineralA

    reate%

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    91.0

    90.5

    90.0

    89.5

    89.0

    88.5

    88.087.5

    87.0

    Ndesign=75

    89.4

    EffectofGradationon%Gmm@Ninitial

    (Part3)

    90.2

    88.3

    90.4

    TRZ ARZ BRZ HRZ

    Figure18:EffectofGradationon%Gmm@Ninital(Ndesign=75),Part3

    gradationhadasimilar%Gmm@NinivalueastheTRZgradation.

    Fortheexperimentalfineaggregatesdesignedat100gyrations,only

    twohadgradationsviolatingtherestrictedzonethatmetvolumetriccriteria(FA-7andFA-9).OnlytheTRZ,ARZ,andBRZgradations wereincludedwiththesefineaggregates.TheARZgradationutilized

    withFA-7failedtomeetthe%Gmm@Ninicriteriaof89.0percentmaximum.TrendsbetweenVMAandgradationshapeweresimilarfor

    theseNdesign=100mixestothoseforParts1and2andthelowercompactiveeffortmixesusedinPart3.TheBRZgradationprovidedthe highestaverageVMAvalueat15.1percentfollowedbytheARZ gradation(14.2percent)andTRZgradation(13.9percent).Trends

    between%Gmm@Niniandgradationshapewerealsosimilartoprevious

    analysesinthatthecoarserthegradation,thelowerthe%G [email protected]%[email protected],withtheARZhavingthehighest(89.1percent)andtheTRZgradationbeingbetweentheBRZandtheARZ(87.6percent).

    39

    mm

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    ResultsofperformancetestingconductedinPart3arealsopresentedinTablesA.21throughA.32intheappendix.ForPart3,the

    APAwasusedastheonlyperformancetestbecauseinPart1andPart

    2theAPAappearedtobemoresensitivetochangesingradation.APA

    resultsformixesdesignedwith75gyrationsinPart3areillustratedin

    Figure19.Rutdepthsforgradationsthatviolatetherestrictedzoneare

    shownwithsolidblackbars,whilerutdepthsforcontrolgradationsare

    shownaslightgraybars.Asexpected,themixcontainingFA-10hada

    highrutdepth.However,theFA-2/BRZgradationhadaslightlyhigherrutdepth.TheremainingmixesshowninFigure19hadsimilarrutdepths. SufficientdatawasavailableforFA-2,FA-4,andFA-7toconduct DMRTrankings.ForFA-4andFA-7,allofthegradationshadsimilarrankingswhichsuggeststhegradationsviolatingtherestrictedzonedid

    notresultinmixesmoresusceptibletorutting.TheFA-2mixesdidshow significantlydifferentrutdepthsforthetwomixestested.Thecontrol

    gradation(BRZ)hadasignificantlyhigherrutdepththanthegradationviolatingtherestrictedzone(HRZ).Baseduponthesedatafor19.0mmNMASdesignedwith75gyrations,itappearsthatgradationspassing

    16

    A

    14

    12

    A

    108

    6

    4

    2

    0

    HRZ

    BRZ

    BHRZ

    ABRZ

    A

    TRZ

    A

    ARZ

    A

    BRZ

    TRZ

    A

    ARZ

    FA-10 FA-2 FA-4 FA-7FAA=38.6 FAA=42.6 FAA=49.7 FAA=48.9Nat.Sand Nat.Sand Sandstone Granite

    Figure19:ResultsofAPATestingConductedonMixes

    DesignedWith75Gyrations,Part3

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    throughtherestrictedzonewillprovidecomparable,ifnotbetter,rutresistancewhencomparedtogradationspassingoutsidetherestricted

    zone.ResultsofAPAtestingconductedonmixesdesignedwith100

    gyrationsforPart3areillustratedinFigure20.Sufficientdatawas availabletoconductDMRTrankingsformixescontainingFA-7andFA-9.MixescontainingFA-7(BRZandTRZ)hadsimilarrutdepthsbasedupontheDMRTrankings.FortheFA-9mixes,theBRZgradation(control)hadasignificantlyhigherrutdepththandidtheTRZandARZ

    gradations.ThisdatasupportthepreviousanalysesinParts1and2and

    theanalysisofthelowerdesigncompactiveeffortworkinPart3.Mixes havinggradationspassingthroughtherestrictedzoneperformsimilarlyor

    14

    12

    10

    8

    6

    4

    2

    0

    HRZ

    A

    BRZ

    A

    TRZ

    A

    BRZ

    B

    TRZ

    B

    ARZ

    FA-10 FA-7 FA-9FAA=38.6 FAA=48.9 FAA=50.1Nat.Sand Granite Diabase

    Figure20:ResultsofAPATestingConductedonMixes

    DesignedWith100GyrationsinPart3

    betterthanmixeshavinggradationspassingoutsidetherestrictedzone.

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    CONCLUSIONSANDRECOMMENDATIONS

    Thefollowingconclusionsaredrawnandrecommendationsmade

    fromthisresearchproject.

    1.MixesmeetingSuperpaveandFAArequirementswithgradationsthatviolatedtherestrictedzoneperformedsimilarlytoorbetterthan

    themixeshavinggradationspassingoutsidetherestrictedzone.This

    conclusionisdrawnfromtheresultsofexperimentswith9.5and19

    mmNMASgradationsatNdesignvaluesof75,100,and125gyrations, andisalsosupportedbyextensive,independentresultsfromthe literature(10,11,12).

    2.TherestrictedzonerequirementisredundantformixesmeetingallSuperpavevolumetricparametersandtherequiredfineaggregateangularity(FAA).ReferencestotherestrictedzoneaseitherrequirementoraguidelineshouldbedeletedfromtheAASHTO

    specificationsandpracticeforSuperpavevolumetricdesignfor

    HMAregardlessofNMASortrafficlevel.

    3.Althoughnotgermanetotheprimaryobjectiveofthisproject,thefollowingobservationsweremade:

    CCoarseaggregatetypehasasignificanteffectonVMAofmixes.Coarse,angulargraniteaggregategenerallyproduced

    higherVMAthanthecoarse,crushedgravelaggregate.CCoarseaggregatetypehasasignificanteffectonthe%[email protected],fineaggregatetypeandgradationtypeappeartohaveamoresignificanteffect.

    CARZandCRZgradationstendtoprovidehigherVMAvalues whiletheTRZgradationprovidedthelowestVMAvalues.

    CTheTRZgradationsgenerallyprovidethelowestVMAvalues forboththe9.5and19.0mmNMASmixes.ThissuggeststhatthemaximumdensitylinedrawnaccordingtotheSuperpaveguidelines(connectingtheoriginofthe0.45powercharttothe

    100percentpassingthemaximumaggregatesize)isreasonably

    locatedonthegradationchart.

    CRelativelyfinergradationmixes(suchasARZandHRZ)tendto havehigher%Gmm@NinivaluescomparedtoTRZ,CRZ,andBRZmixes.

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    C HighFAAvaluesdonotnecessarilyproducehighVMAinmixesalthoughtherewasageneraltrendofincreasingVMAvaluesforincreasingFAA.

    C HigherFAAvaluesgenerallyproducedlower%[email protected]

    metthe%Gmm@Ninirequirementsof89percentandlowerfor themixespreparedatNdesign=100and125.ThisindicateshighFAAvaluescontributetoastifferfineaggregate/asphaltcomponentinHMAatinitialcompactionlevels.

    C Noneofthemixesfailedthe%[email protected],thevalidityofthisrequirementshouldbeexamined.

    C Numerousmixdesignsinthisstudyexceededthemaximum

    VFArequirementof75percent.TheSuperpaverequirementof 65.0to75.0percentforVFAeffectivelylimitstheVMAof9.5 mmNMASmixestoanarrowrange.BothVMAandVFA requirementsfor9.5mmNMASSuperpavemixdesignneedto

    beevaluated.

    C ThepotentialofmixesfailingduetoexcessiveVMA(morethan2percentabovetheminimumspecifiedvalue)increaseswitha lowerdesigncompactiveeffort,angularcoarseaggregate

    content,andhighFAAvalues.

    C BoththeAsphaltPavementAnalyzer(APA)andtheRepeated LoadConfinedCreep(RLCC)testwerereasonablysensitiveto

    thegradationofmixes.TheRepeatedShearatConstantHeight(RSCH)testconductedwiththeSuperpaveShearTesterwasnotfoundtobeassensitivetochangesingradation.

    ACKNOWLEDGMENT

    ThispaperisbasedonthestudyconductedbytheNationalCenter

    forAsphaltTechnologyfortheNationalCooperativeHighwayResearch,

    Project9-14,onrestrictedzoneintheSuperpavegradation.

    REFERENCES

    1.Cominsky,Ronald,RitaB.Leahy,andEdwardT.Harrigan(1994).LevelOneMixDesign:MaterialsSelection,Compaction,and

    43

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    Conditioning.StrategicHighwayResearchProgram.SHRP-A-408.NationalResearchCouncil,Washington,DC,1994.

    2.Watson,DonaldE.,AndrewJohnson,andDavidJared(1997).The

    SuperpaveGradationRestrictedZoneandPerformanceTestingwith

    theGeorgiaLoadedWheelTester.TransportationResearchRecord

    No.1583,TransportationResearchBoard,NationalAcademyPress,

    Washington,DC,1997.

    3.Kandhal,PrithviS.andL.AllenCooley,Jr.InvestigationoftheRestrictedZoneintheSuperpaveAggregateGradationSpecification.

    NCHRP9-14DraftFinalReport,July2001.

    4.Anderson,R.MichaelandHussainU.Bahia(1997).Evaluationand SelectionofAggregateGradationsforAsphaltMixturesUsingSuperpave.TransportationResearchRecord1583,Transportation

    ResearchBoard,Washington,DC,1997.

    5.McGennis,RobertB.(1997).EvaluationofMaterialsfromNortheastTexasUsingSuperpaveMixDesignTechnology.Presentedatthe76thAnnualMeetingoftheTransportationResearchBoard,

    Washington,DC,1997.

    6.Kandhal,PrithviS.andR.B.Mallick(1999).PotentialofAsphalt

    PavementAnalyzer(APA)toPredictRuttingofHotMixAsphalt.Proceedings,1999InternationalConferenceonAcceleratedPavementTesting,Reno,NV,October18-20,1999.

    7.PerformanceofCoarse-GradedMixesatWesTrack-PrematureRutting.FederalHighwayAdministration.FinalReport,June1998.

    8.Gabrielson,J.R.EvaluationofHotMixAsphalt(HMA)StaticCreep andRepeatedLoadTests.Ph.D.Dissertation,AuburnUniversity,

    Auburn,Alabama,December16,1992.

    9.Romero,PedroandR.M.Anderson.VariabilityofAsphaltMixturesTestsUsingtheSuperpaveShearTesterRepeatedShearat ConstantHeightTest.PaperNo.01-2098presentedatAnnual MeetingoftheTransportationResearchBoard,WashingtonDC,

    44

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    January2001.

    10.Chowdhury,Arif,JoseC.Grau,JoeW.Button,andDallasN.Little (2001).EffectofGradationonPermanentDeformationofSuperpave HMA.Presentedatthe80thAnnualMeetingoftheTransportation

    ResearchBoard,Washington,DC,2001.

    11.Hand,AdamJ.andAmyL.Epps(2001).ImpactofGradationRelativetotheSuperpaveRestrictedZoneorHMAPerformance.Presentedatthe80thAnnualMeetingoftheTransportation

    ResearchBoard,Washington,DC,2001.

    12.Kandhal,PrithviS.andRajibB.Mallick(2001).EffectofMix

    GradationonRuttingPotentialofDenseGradedAsphaltMixtures.Presentedatthe80thAnnualMeetingoftheTransportation

    ResearchBoard,Washington,DC.

    45

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    APPENDIX

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    TableA.1:SummaryofMixDesignsandPerformanceDataforFA-10,Part1,Ndesign=100,9.5mmNMAS

    FAA=38.6,QuartzSand

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphalt Content

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    HRZ

    HRZ

    Agg.

    Granite

    CrushedGravel

    Content,%

    4.2

    4.0

    VTM,%

    4.0

    4.0

    VMA,%

    13.1*

    12.8*

    VFA,%

    69.5

    68.8

    %Gmm@N

    ini

    91.5*

    91.4*

    %Gmm@N

    max

    97.3

    97.3

    Depth,mm

    5.54

    10.94

    %

    1.158

    1.247

    %

    22.20

    25.11

    VolumetricRequirementsfor 4.0 15.0 65to 89.0 98.0

    Part1 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements.

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    TableA.2:SummaryofPart1MixDesignsandPerformanceDataforFA-1,Ndesign=100,9.5mmNMAS

    FAA=40.7,QuartzSand

    Opt. VolumetricPropertiesatOptimumAsphaltContentGrad. CoarseAgg. Asphalt

    Content,% VTM,% VMA,% VFA,% %Gmm@Nini %Gmm@Nmax

    BRZ Granite 4.4 4.0 13.8* 71.0 90.3* 97.5

    ARZ Granite 4.8 4.0 14.6* 72.6 91.2* 97.2

    TRZ Granite 4.2 4.0 13.1* 69.5 91.0* 97.7

    HRZ Granite 4.3 4.0 13.6* 70.6 91.3* 97.3

    CRZ Granite 4.4 4.0 13.9* 71.2 90.3* 97.6

    BRZ Crushed 4.1 4.0 12.7* 68.5 90.6* 97.2Gravel

    ARZ Crushed 4.7 4.0 13.8* 71.0 91.5* 97.4Gravel

    TRZ Crushed 4.0 4.0 12.3* 67.5 91.3* 97.6Gravel

    HRZ Crushed 4.3 4.0 13.3* 69.9 91.3* 97.5

    Gravel

    CRZ Crushed 4.2 4.0 13.0* 69.2 90.9* 97.6Gravel

    VolumetricRequirementsforPart1 4.0 15.0min. 65to75 89.0max. 98.0max.*DoesnotmeetSuperpaverequirements.

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    TableA.3:SummaryofPart1MixDesignsandPerformanceDataforFA-2,Ndesign=100,9.5mmNMAS

    FAA=42.6,QuartzSandwithSomeChert

    Opt.

    VolumetricPropertiesatOptimumAsphaltContent

    Grad.BRZ

    ARZTRZ

    HRZ

    CRZ

    BRZ

    ARZ

    TRZ

    HRZ

    CRZ

    CoarseAgg.Granite

    GraniteGranite

    Granite

    Granite

    CrushedGravel

    CrushedGravel

    CrushedGravel

    CrushedGravel

    CrushedGravel

    AsphaltContent,%

    5.5

    5.45.1

    5.3

    5.5

    5.1

    5.1

    4.6

    4.8

    5.0

    VTM,%

    4.0

    4.04.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    VMA,%

    15.9

    15.715.2

    15.4

    15.8

    14.8*

    14.5*

    13.9*

    14.1*

    14.5*

    VFA,%

    74.7

    74.573.7

    74.0

    74.9

    73.0

    72.4

    71.2

    71.4

    72.4

    %Gmm@Nini

    89.1*

    91.2*90.2*

    90.8*

    90.2*

    89.5*

    91.2*

    90.7*

    91.0*

    90.4*

    %Gmm@Nmax

    97.6

    97.697.5

    97.8

    97.4

    97.3

    97.3

    96.9

    96.8

    97.0

    VolumetricRequirementsforPart1 4.0 15.0min. 65to75 89.0max. 98.0max.

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    *DoesnotmeetSuperpaverequirements.

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    TableA.4:SummaryofPart1MixDesignsandPerformanceDataforFA-3,Ndesign=100,9.5mmNMAS

    FAA=44.1,QuartzSandwithSomeChert

    Opt. VolumetricPropertiesatOptimumAsphaltContentGrad. CoarseAgg. Asphalt

    Content,% VTM,% VMA,% VFA,% %Gmm@Nini %Gmm@Nmax

    BRZ Granite 4.5 4.0 13.8* 71.0 90.5* 97.6

    ARZ Granite 5.2 4.0 14.8* 73.0 90.7* 97.4

    TRZ Granite 4.3 4.0 13.1* 69.5 90.2* 97.7

    HRZ Granite 4.9 4.0 14.3* 72.0 90.9* 97.7

    CRZ Granite 4.7 4.0 14.1* 71.4 90.3* 97.4

    BRZ Crushed 4.3 4.0 12.7* 68.5 89.9* 97.0Gravel

    ARZ Crushed 4.9 4.0 13.5* 70.4 91.2* 97.4Gravel

    TRZ Crushed 4.2 4.0 12.6* 68.3 90.8* 97.5Gravel

    HRZ Crushed 4.3 4.0 12.6* 68.3 90.7* 97.6

    Gravel

    CRZ Crushed 4.5 4.0 12.9* 69.0 90.4* 97.6Gravel

    VolumetricRequirementsforPart1 4.0 15.0min. 65to75 89.0max. 98.0max.*DoesnotmeetSuperpaverequirements.

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    TableA.5:SummaryofPart1MixDesignsandPerformanceDataforFA-6,Ndesign=100,9.5mmNMAS

    FAA=46.5,Limestone

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphalt Content

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    Agg.

    Granite

    Granite

    Granite

    Granite

    CrushedGravel

    Crushed

    Gravel

    CrushedGravel

    CrushedGravel

    Content,%

    5.3

    5.3

    5.0

    5.7

    4.6

    4.5

    4.3

    4.6

    VTM,%

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    VMA,%

    14.1*

    14.2*

    13.4*

    14.8*

    12.1*

    12.0*

    11.4*

    12.4*

    VFA,%

    71.6

    71.8

    70.1

    73.0

    66.9

    66.7

    64.9*

    67.7

    %Gmm@N

    ini

    85.4

    87.8

    86.7

    87.4

    85.9

    87.9

    87.1

    86.4

    %Gmm@N

    max

    97.7

    97.6

    97.6

    97.8

    97.9

    97.6

    97.5

    97.7

    Depth,mm

    4.82

    4.55

    4.31

    5.54

    ---

    ---

    ---

    ---

    %

    1.105

    1.126

    0.943

    1.295

    ---

    ---

    ---

    ---

    %

    3.19

    1.40

    1.80

    2.88

    ---

    ---

    ---

    ---

    VolumetricRequirementsfor 4.0 15.0 65to 89.0 98.0 --- --- ---Part1 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements.

    52

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    TableA.6:SummaryofPart1MixDesignsandPerformanceDataforFA-8,Ndesign=100,9.5mmNMAS

    FAA=48.3,Limestone

    Opt.

    VolumetricPropertiesatOptimumAsphaltContent

    Grad.BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    CoarseAgg.Granite

    Granite

    Granite

    Granite

    CrushedGravel

    CrushedGravel

    CrushedGravel

    CrushedGravel

    AsphaltContent,%

    4.9

    5.1

    4.8

    5.3

    4.5

    4.7

    4.3

    5.0

    VTM,%

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    VMA,%

    12.7*

    13.1*

    12.5*

    13.6*

    12.5*

    12.9*

    11.7*

    13.3*

    VFA,%

    68.5

    69.5

    68.1

    70.7

    68.0

    69.0

    65.8

    69.9

    %Gmm@Nini

    85.0

    87.7

    86.5

    85.7

    85.6

    88.0

    86.3

    86.7

    %Gmm@Nmax

    97.3

    97.1

    97.7

    97.4

    97.9

    97.9

    97.8

    97.9

    VolumetricRequirementsforPart1 4.0 15.0min. 65to75 89.0max. 98.0max.

    *DoesnotmeetSuperpaverequirements.

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    TableA.7:SummaryofPart1MixDesignsandPerformanceDataforFA-7,Ndesign=100,9.5mmNMAS

    FAA=48.9,Granite

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphalt Content

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    Agg.

    Granite

    Granite

    Granite

    Granite

    CrushedGravel

    Crushed

    Gravel

    CrushedGravel

    CrushedGravel

    Content,%

    6.0

    5.9

    5.7

    6.4

    5.4

    5.7

    5.0

    5.6

    VTM,%

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    VMA,%

    16.8

    16.5

    16.1

    17.6**

    15.1

    15.7

    14.7*

    15.7

    VFA,%

    76.2*

    75.8*

    75.2

    77.3*

    73.5

    74.5

    72.8

    74.5

    %Gmm@N

    ini

    86.9

    89.5*

    88.3

    87.8

    87.6

    89.7*

    88.9

    88.3

    %Gmm@N

    max

    97.6

    97.5

    97.4

    97.5

    97.4

    97.6

    97.4

    97.7

    Depth,mm

    4.62

    ---

    4.97

    ---

    7.64

    ---

    ---

    7.76

    %

    1.589

    ---

    0.964

    ---

    1.198

    ---

    ---

    1.444

    %

    3.75

    ---

    3.82

    ---

    11.17

    ---

    ---

    12.62

    VolumetricRequirementsfor 4.0 15.0 65to 89.0 98.0 --- --- ---Part1 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements.

    55

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    **ExcessiveVMA(morethan2percentaboveminimum)

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    TableA.8:SummaryofPart1MixDesignsandPerformanceDataforFA-4,Ndesign=100,9.5mmNMAS

    FAA=49.7,Sandstone

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphalt Content

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    Agg.

    Granite

    Granite

    Granite

    Granite

    CrushedGravel

    Crushed

    Gravel

    CrushedGravel

    CrushedGravel

    Content,%

    6.0

    6.1

    5.8

    6.2

    5.6

    5.7

    5.3

    5.6

    VTM,%

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    VMA,%

    16.9

    16.8

    16.4

    17.0

    15.8

    16.2

    15.2

    15.9

    VFA,%

    76.3*

    76.2*

    75.6*

    76.5*

    74.7

    75.3*

    73.7

    74.8

    %Gmm@N

    ini

    85.8

    88.7

    88.6

    87.9

    87.0

    89.0

    88.4

    86.8

    %Gmm@N

    max

    97.9

    97.8

    97.5

    97.7

    97.6

    97.8

    97.7

    97.6

    Depth,mm

    7.84

    7.28

    7.06

    7.53

    8.77

    7.83

    6.46

    7.86

    %

    1.309

    1.301

    1.359

    1.573

    1.295

    1.251

    1.250

    1.879

    %

    8.79

    5.57

    3.93

    7.07

    12.08

    11.97

    5.44

    8.40

    VolumetricRequirementsfor 4.0 15.0 65to 89.0 98.0 --- --- ---Part1 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements.

    57

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    TableA.9:SummaryofPart1MixDesignsandPerformanceDataforFA-9,Ndesign=100,9.5mmNMAS

    FAA=50.1,Diabase(Traprock)

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphalt Content

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    Agg.

    Granite

    Granite

    Granite

    Granite

    CrushedGravel

    Crushed

    Gravel

    CrushedGravel

    CrushedGravel

    Content,%

    6.1

    5.7

    5.6

    6.4

    6.0

    5.5

    5.3

    5.7

    VTM,%

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    VMA,%

    17.3**

    16.6

    16.2

    17.4**

    16.7

    15.7

    15.3

    16.2

    VFA,%

    76.9*

    75.9*

    75.3*

    77.0*

    76.0*

    74.5

    73.8

    75.3*

    %Gmm@N

    ini

    86.4

    88.6

    87.2

    86.4

    88.4

    87.8

    87.8

    86.8

    %Gmm@N

    max

    97.6

    97.7

    97.6

    97.8

    97.5

    97.6

    97.3

    97.4

    Depth,mm

    ---

    5.12

    4.64

    ---

    7.10

    5.37

    5.76

    5.49

    %

    ---

    0.924

    0.854

    ---

    2.087

    1.942

    ---

    1.115

    %

    ---

    0.83

    4.70

    ---

    6.36

    2.62

    13.70

    7.29

    VolumetricRequirementsfor 4.0 15.0 65to 89.0 98.0 --- --- ---Part1 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements.

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    **ExcessiveVMA(morethan2percentaboveminimum)

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    TableA.10:SummaryofPart1MixDesignsandPerformanceDataforFA-5,Ndesign=100,9.5mmNMAS

    FAA=50.3,Dolomite

    Grad.

    Coarse

    Opt.

    Asphalt

    VolumetricPropertiesatOptimumAsphaltContent

    BRZ

    ARZ

    TRZ

    CRZ

    BRZ

    ARZ

    TRZ

    CRZ

    Agg.

    Granite

    Granite

    Granite

    Granite

    Crushe

    dGravel

    CrushedGravel

    Crushed

    Gravel

    Crushed

    Gravel

    Content,%

    4.8

    5.0

    4.7

    4.9

    4.4

    4.7

    4.2

    4.4

    VTM,%

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    4.0

    VMA,%

    14.4*

    15.1

    14.4*

    14.6*

    13.5*

    14.2*

    13.2*

    13.4*

    VFA,%

    72.2

    73.5

    72.2

    72.6

    70.4

    71.8

    69.7

    70.1

    %Gmm@

    Nini

    86.2

    88.9

    87.8

    87.1

    86.9

    89.3*

    88.7

    87.4

    %Gmm@N

    max

    97.3

    97.3

    97.9

    97.1

    97.6

    97.6

    97.8

    97.6

    VolumetricRequirementsfor 4.0 15.0min. 65to75 89.0max. 98.0max.

    Part1

    *DoesnotmeetSuperpaverequirements.

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    TableA.11:SummaryofPart2MixDesignsandPerformanceDataforFA-10,Ndesign=75,9.5mmNMAS

    FAA=38.6,QuartzSand

    Grad.

    Coarse

    Opt.AsphaltContent,

    VolumetricPropertiesatOpt.AsphaltContent

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    HRZ

    Agg.

    Granite

    %4.5

    VTM,%

    4.0

    VMA,%

    13.8*

    VFA,%

    71.0

    %Gmm@Nini

    90.6

    %Gmm@Nmax

    97.9

    Depth,mm

    16.01

    %

    6.569

    %

    37.04

    VolumetricRequirements 4.0 15.0 65to 90.5 98.0

    forPart2 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements

    63

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    TableA.12:SummaryofPart2MixDesignsandPerformanceDataforFA-2,Ndesign=75,9.5mmNMAS

    FAA=42.6,QuartzSandwithSomeChert

    Grad

    Coarse

    Opt.

    Asphalt

    VolumetricPropertiesatOpt.AsphaltContent APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,.

    BRZ

    TRZ

    CRZ

    HRZ

    Agg.

    Granite

    Granite

    Granite

    Granite

    Content,%

    6.2

    5.7

    6.4

    5.9

    VTM,%

    4.0

    4.0

    4.0

    4.0

    VMA,%

    17.4**

    16.3

    17.7**

    17.1**

    VFA,%

    77.0*

    75.5*

    77.4*

    76.6*

    %Gmm

    @Nini

    89.2

    90.4

    90.1

    90.0

    %Gmm

    @Nmax

    97.5

    97.3

    97.6

    97.3

    Depth,mm

    ---

    15.15

    ---

    ---

    %

    ---

    6.472

    ---

    ---

    %

    ---

    17.90

    ---

    ---

    VolumetricRequirements 4.0 15.0 65to 90.5 98.0 --- --- ---forPart2 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements**ExcessiveVMA(morethan2percentaboveminimum)

    64

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    TableA.13:SummaryofPart2MixDesignsandPerformanceDataforFA-3,Ndesign=75,9.5mmNMAS

    FAA=44.1,QuartzSandwithSomeChert

    Grad

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphaltContent

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,.

    BRZ

    TRZ

    CRZ

    HRZ

    Agg.

    Granite

    Granite

    Granite

    Granite

    Content,%

    5.4

    4.9

    5.6

    5.0

    VTM,%

    4.0

    4.0

    4.0

    4.0

    VMA,%

    15.9

    14.4*

    15.9

    14.6*

    VFA,%

    74.8

    72.2

    74.8

    72.6

    %Gmm@N

    ini

    89.8

    90.7*

    90.3

    89.9

    %Gmm@N

    max

    97.5

    97.2

    97.4

    97.1

    Depth,mm

    18.57

    ---

    17.39

    ---

    %

    3.920

    ---

    7.200

    ---

    %

    **

    ---

    **

    ---

    VolumetricRequirementsfor 4.0 15.0 65to 90.5 98.0 --- --- ---Part2 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements**Testspecimensfailedprematurelybefore3600loadapplications

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    TableA.14:SummaryofPart2MixDesignsandPerformanceDataforFA-6,Ndesign=75,9.5mmNMAS

    FAA=46.5,Limestone

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphaltContent

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    BRZ

    TRZ

    CRZ

    Agg.

    Granite

    Granite

    Granite

    Content,%

    5.8

    5.2

    5.9

    VTM,%

    4.0

    4.0

    4.0

    VMA,%

    15.9

    14.4*

    16.0

    VFA,%

    74.8

    72.2

    75.0

    %Gmm@N

    ini

    86.4

    87.0

    86.5

    %Gmm@N

    max

    97.3

    97.6

    97.4

    Depth,mm

    7.33

    ---

    7.25

    %

    2.885

    ---

    2.541

    %

    7.35

    ---

    6.63

    VolumetricRequirementsfor 4.0 15.0 65to 90.5 98.0 --- --- ---

    Part2 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements

    66

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    TableA.15:SummaryofPart2MixDesignsandPerformanceDataforFA-7,Ndesign=75,9.5mmNMAS

    FAA=48.9,Granite

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphaltContent

    APA

    Rut

    RSCH

    Strain,

    RLCC

    BRZTRZ

    CRZ

    Agg.

    Granite

    Granite

    Granite

    Content,%

    6.3

    6.0

    6.7

    VTM,%

    4.0

    4.0

    4.0

    VMA,%

    17.4**

    16.8

    18.4*

    *

    VFA,%

    77.0*

    76.2*

    78.2*

    %Gmm@N

    ini

    87.8

    88.7

    88.1

    %Gmm@N

    max

    97.8

    97.6

    97.5

    Depth,mm

    ---

    10.25

    ---

    %

    ---2.449

    ---

    Strain,%---

    8.81

    ---

    VolumetricRequirements 4.0 15.0 65to 90.5 98.0 --- --- ---forPart2 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements**ExcessiveVMA(morethan2percentaboveminimum)

    67

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    TableA.16:SummaryofPart2MixDesignsandPerformanceDataforFA-4,Ndesign=75,9.5mmNMAS

    FAA=49.7,Sandstone

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphalt Content

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    BRZ

    TRZ

    CRZ

    Agg.

    Granite

    Granite

    Granite

    Content,%

    6.1

    5.7

    6.2

    VTM,%

    4.0

    4.0

    4.0

    VMA,%

    17.2**

    16.3

    17.4**

    VFA,%

    76.7*

    75.5*

    77.0*

    %Gmm@N

    ini

    86.6

    87.5

    87.2

    %Gmm@N

    max

    97.5

    97.6

    97.7

    Depth,mm

    ---

    8.45

    ---

    %

    ---

    1.183

    ---

    %

    ---

    11.13

    ---

    VolumetricRequirements 4.0 15.0 65to 90.5 98.0 --- --- ---

    forPart2 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements**ExcessiveVMA(morethan2percentaboveminimum)

    68

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    TableA.17:SummaryofPart2MixDesignsandPerformanceDataforFA-10,Ndesign=125,9.5mmNMAS

    FAA=48.9,Granite

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOptimumAsphalt Content

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,

    HRZ

    Agg.Granite

    Content,%

    3.6

    VTM,%

    4.0

    VMA,%

    12.6*

    VFA,%

    68.3

    %Gmm@N

    ini

    89.5*

    %Gmm@N

    max

    97.9

    Depth,mm

    10.51

    %

    2.641

    %

    24.795

    VolumetricRequirementsfor 4.0 15.0 65to 90.5 98.0 --- --- ---Part2 min. 75 max. max.

    *DoesnotmeetSuperpaverequirements

    TableA.18:SummaryofPart2MixDesignsandPerformanceDataforFA-7,Ndesign=125,9.5mmNMAS

    FAA=48.9,Granite

    Grad.

    Coarse

    Opt.Asphalt

    VolumetricPropertiesatOpt.AsphaltContent

    APA

    Rut

    RSCH

    Strain,

    RLCC

    Strain,Agg.

    BRZ

    TRZ

    CRZ

    Granite

    Granite

    Granite

    Content,%


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