investigation of the restricted zone in the superpave aggregate gradation specifications
TRANSCRIPT
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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
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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).
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VoidsinMineralA
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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
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
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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
23
mm
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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
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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
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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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PlasticStrain%
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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
35
PlasticStrain%
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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
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VoidsinMineralA
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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).
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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
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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,
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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.
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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.
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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.
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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.
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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.
61
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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
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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
65
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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
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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,%