| Date post: | 10-Jul-2018 |
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BalancedMixDesign(BMD)
ASPHALT PAVEMENT ASSOCIAT ION OF MICHIGAN (APAM)2017 ASPHALT PAVING CONFERENCE
SHANE BUCHANANOLDCASTLE MATERIALS
DiscussionItems
NeedforBalancedMixDesign PerformanceTestingDiscussion BalancedMixDesignTaskForceActivities AgencyPracticesRelatedtoBalancedMixDesign
FutureWork
AMAP|2017
Asphaltmixdesignusingperformancetestsonappropriatelyconditionedspecimensthataddressmultiplemodesofdistresstakingintoconsiderationmixaging,traffic,climateandlocationwithinthepavementstructure.
Basically,itconsistsofdesigningthemixforanintendedapplicationandservicerequirement(e.g.,usetherighttoolforthejob!)
BalancedMixDesignDefinition
AMAP|2017
NeedforBalancedMixDesign
Problems: Relyingonvolumetricsalonetoprovide
performance Drymixesexistinsome(notall)areas
Solutions: Recognizeperformanceissuesrelatedtodrymixes
insomeareas.(Note:Manyperformanceissuesarecausedbyfactorsoutsidethemixdesign)
Increaseunderstanding ofthefactorswhichdrivemixperformance
Designforperformanceandnotjusttothespec. Startthinkingoutsideoflongheldrulesand
constraints Innovate!
WhytheNeedforaNewMixDesignApproach?
2017APAMPavingConference
WhatTypeDistressIsOccurring?
OldcastleSurveyQuestion:Withinthepast5years,whattypeofmixperformancerelateddistresshasbeenmostevidentinyourmixes?
~40companiesrespondingfrom~30states
OldcastleSurveyQuestion:Withinthepast5years,whattypeofmixperformancerelateddistresshasbeenmostevidentinyourmixes?
~40companiesrespondingfrom~30states
2017APAMPavingConference
Eachday,approximately1.4MilliontonsofHMAareproducedintheU.S.(MFproductionbasis) [email protected]
DistancefromNewYorktoLasVegas
StepsMustbeTakenNow TowardsSolutions
Longtermresearchiscertainlyneeded,butwemusttakestepsNOW towardsasolution
2017APAMPavingConference
Largelyrecipedriven Aggregatesandgrading Volumetrics(Va,VMA,VFA,D/A,etc.) Bindergradeand/orminimum% RAPand/orRAS WMA
Whilethismay work,thereareproblems Whathappenswhentherecipefails?
Specificationshavebecomeconvolutedandconfounded Existingspecifieditemscompeteagainsteachother Newrequirementsgetaddedandnothinggetsremoved SpecBookCreep
Innovationhasbecomestifledwithourknowledgeoutpacingspecifications
MixDesignSpecifications
2017APAMPavingConference
State GyrationLevel1
NewMexico 75,100,125NewYork 50,75,100
NorthCarolina 50,65,75,100Ohio 65Oklahoma 6422(50),7028(60),and7628(80)Oregon 65,80,100
Pennsylvania 50,75,100RhodeIsland 50Tennessee 65or75MarshallTexas 50Utah 50,75,100,125Vermont 50,65,80Virginia 65
Washington 50,75,100,125WestVirginia 50,65,80,100
State GyrationLevel1
Alabama 60Arkansas 50,75,100,125Colorado 75,100Connecticut 75,100
Florida 50,65,75,100
Idaho 50,75,100,125Iowa 50,60,65,68,76,86,96,109,126Kansas 75,100
Kentucky 50,75,100Maine 50,75Massachusetts 50,75,100Michigan 45,50,76,86,96,109,126
Minnesota 40,60,90,100Mississippi 50,65,85
Missouri 50,75,80,100,125Montana 75Nebraska 40,65,95
Nevada UseHveemNewHampshire 50,75NewJersey 50,75
Ndesignvarieswidelyw/levelsbeingreducedwiththeintentofgainingmorebinder
Problem:Lowergyrationsdonotnecessarilyequatetomorebinder
AgenciesareSearchingforSolutions:Ndesign
AsofMarch2015
2017APAMPavingConference
SouthCarolina:50,75,100
EnhancingtheDurabilityofAsphaltPavements
VolumeofEffectiveBinder(Vbe)istheprimarymixturedesignfactoraffectingbothdurabilityandfatiguecrackingresistance. Vbe=VMA AirVoids
Anumberofstatehighwayagencieshavedecreasedthedesigngyrationlevelsinanattempttoincreaseeffectivebindercontents.However,decreasingthedesigngyrationsmaynotalwaysproducemixtureswithhigherVbe.
2017APAMPavingConference
Superpavesystemisbecomingunrecognizablewithspecificationschangingrapidlyasagenciessearchforwaystoimprovedurability
Establishingtruecauseandeffectisimpossible
AgenciesAreSearchingforSolutions:SpecChanges
SurveyQuestion:WhichofthefollowingspecificationchangeshasyourDOTimplementedinthelast5years?
SurveyQuestion:WhichofthefollowingspecificationchangeshasyourDOTimplementedinthelast5years?
2017APAMPavingConference
MichiganNdesign
2017APAMPavingConference
MichiganAirVoidRegression
2017APAMPavingConference
Mix3:
VMAMin.=13% VFA(E10)=65to78%
EnsureSpecificationItemsAgree
2017APAMPavingConference
VMAMinimum,% 13UpperVFA,% 78LowerVFA,% 65EffectiveUpperVa,% 4.55EffectiveLowerVa,% 2.86EffectiveUpperVbe,% 10.14EffectiveLowerVbe,% 8.45
Mix5:
VMAMin.=15% VFA(E10)=73to76%
EnsureSpecificationItemsAgree
2017APAMPavingConference
VMAMinimum,% 15UpperVFA,% 76LowerVFA,% 73EffectiveUpperVa,% 4.05EffectiveLowerVa,% 3.6EffectiveUpperVbe,% 11.4EffectiveLowerVbe,% 10.95
1890BarberAsphaltPavingCompanyAsphaltcement12to15%/Sand70to83%/Pulverizedcarboniteoflime5to15%
1905
CliffordRichardson,NewYorkTestingCompanySurfacesandmix:100%passingNo.10,15%passingNo.200,9to14%asphaltAsphalticconcreteforlowerlayers,VMAterminologyused,2.2%moreVMAthancurrentdaymixesor~0.9%higherbindercontent
1920s
HubbardFieldMethod(CharlesHubbardandFrederickField)Sandasphaltdesign30blow,6diameterwithcompressiontest(performance)asphalticconcretedesign(ModifiedHFMethod)
1927
FrancisHveem(Caltrans)Surfaceareafactorsusedtodeterminebindercontent;HveemstabilometerandcohesionmeterusedAirvoidsnotusedinitially,mixesgenerallydrierrelativetoothers,fatiguecrackinganissue
1943
BruceMarshall,MississippiHighwayDepartmentRefinedHubbardFieldmethod,standardcompactionenergywithdrophammerInitially,onlyusedairvoidsandVFA,VMAaddedin1962;stabilityandflowutilized
1993
Superpave Level1(volumetric) Level2and3(performancebased,butnever implemented)
HistoryofMixDesign
http://asphaltmagazine.com/historyofasphaltmixdesigninnorthamericapart2/
BINDER
CONTENT
LOWER
Stability
Stability+Durability
Stability+Durability
2017APAMPavingConference
Designandoptimumbindercontentareoftenusedinterchangeably However,theymeantwodifferentthings
Therecanbemanydesignbindercontentsforamix,butonlyonetrulyoptimum
Optimumindicatesthebestbindercontentbasedonintendedapplication,performancerequirements/needs,andultimatelyeconomics
Goalistogetascloseaspossibletothetrueoptimum forthemix
BinderContent Designvs.Optimum(Thereisadifference!)
2017APAMPavingConference
PerformanceTestingofAsphaltMixes
StabilityTesting
Evaluatemixstabilitywithoneofseveralavailableruttingtools. Hamburg,APA,AMPTFlowNumber,etc. Failurecriteria
Basedonbestavailableresearch(local,regional,ornational) Functionoftraffic(e.g.,low,medium,high)and/ormixenduseapplications
StabilityEvaluation
2017APAMPavingConference
Durability/CrackingTesting
Durability/crackingevaluationissubstantiallymorecomplicatedthanstability Whatisthemodeofdistress? Whatistheagingcondition?
Crackingpredictionisaknownweaklinkinperformancetesting Nogeneralconsensusonthebesttest(s)
ortheappropriatefailurethreshold
GOALS MATCHTHETESTTOTHEDISTRESS SETAPPROPRIATEFAILURETHRESHOLDS
Durability/CrackingEvaluation
2017APAMPavingConference
LaboratoryCrackingTests(From:ResearchReportNo.FHWAICT15017)
AMAP|2017
MatchtheTesttotheDistress
From:LouayMohammad,LTRC
DiscShapedCompactTension
2017APAMPavingConference
CrackingTests:StrainandCyclesIllustration
2017APAMPavingConference
WhatistheBestCrackingTest?ItDepends!
NCHRP957:ExperimentalDesignforFieldValidationofLaboratoryTeststoAssessCrackingResistanceofAsphaltMixtures
Note:SCBILisnowIFITAMAP|2017
UseofPerformanceTestinginDesign Illinois
From:ImadAlQadi,UniversityofIllinois AMAP|2017
UseofPerformanceTestinginDesignWisconsin
From:Erv.Dukatz,MathyConstruction,TRB2015 AMAP|2017
Performancespacediagramsshowtheperformanceofamixrelatedtomultipletests
Allowsthemixdesignertovisualizethemixperformanceandhowtoengineerthemixtoprovidethedesiredperformance
UsingPerformanceResultstoOptimizePerformance
AMAP|2017
BalancedMixDesignTaskForce DevelopmentandWork
AttherequestoftheNationalPavementImplementationExecutiveTaskGroup(PIETG) aBalancedMixDesignTaskForceformedattheSeptember2015FHWAMixtureandConstructionETGmeeting
ThePIETGisfocusedonthestrategicprogramlevelchallengesandopportunitiesinthedeploymentofpavementtechnologies.
Focusareasinclude:
PavementDesignandAnalysis;
PavementMaterialsandQualityAssurance;
PavementSurfaceCharacteristics;
ConstructionTechnology;
PavementSustainability;
TechnicalCapacity;and
FieldSupport/TechnicalAssistance.
PavementImplementationExecutiveTaskGroup(PIETG)
AMAP|2017
AMAP|2017
JohnBukowski Materials TeamLeaderChristopherWagner PavmentandMaterials Tech.Srvs.TeamLeaderGinaAhlstrom PavementDesignandAnalysis TeamLeaderJeffWithee PavementMaterials EngineerMarkSwanlund InfrastructureR&DProgramCoordinatorBryanCawley ConstructionMgmt.TeamLeaderStephenGaj AssetMgmt.TeamLeaderHari Kalla Director,OfficeofAssetMgmt.,Pavement&Construction
MikeAcott President NAPAAudreyCopeland VP,Engineeering,Tech.andResearch NAPA(attendee)GeraldVoigt President/CEO ACPALeifWathne VP,HighwaysandFederal Affairs ACPA(alternate)JimDuit President DuitConstruc
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