BalancedMixDesign(BMD)TaskForceUpdate

FHWAExpertTaskGrouponAsphaltMixtures

DAVE NEWCOMB

OurLeader

ShaneBuchanan,OldcastleMaterialsGroup

TaskForceMembers

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Name Affilation Category e-mailDaveNewcomb TexasTransportationInstitute Academia/Research d-newcomb@ttimail.tamu.eduJohnHaddock PurdueUniversity Academia/Research jhaddock@purdue.eduKevinHall UniversityofArkansas Academia/Research kdhall@uark.eduLouayMohammad LouisianaStateUniversity Academia/Research Louaym@Lsu.eduBrianPfeifer IllinoisDOT Agency Brian.Pfeifer@illinois.govBryanEngstrom MassachusettsDOT Agency Brian.Pfeifer@illinois.govCharliePan NevadaDOT Agency cpan@dot.state.nv.usCurtTurgeon MinnesotaDOT Agency curt.turgeon@state.mn.usDerekNener-Plante MaineDOT Agency derek.nener-plante@maine.govElianaCarlson ConnecticutDOT Agency Eliana.Carlson@CT.govHowardAnderson UtahDOT Agency handerson@utah.govOakMetcalfe MontanaDOT Agency rmetcalfe@mt.govRobertLee TexasDOT Agency Robert.Lee@txdot.govStevenHefel WisconsinDOT Agency Steven.Hefel@dot.wi.govFrankFee Consultant Consultant frank.fee@verizon.netJohnD'Angelo Consultant Consultant johndangelo@dangeloconsultingllc.comLeeGallivan Consultant Consultant lee@gallivanconsultinginc.comRichardDuval FHWA-TurnerFairbank FHWAAgency Richard.Duval@dot.govTimAschenbrener FHWA-Denver FHWAAgency timothy.aschenbrener@dot.govAndrewHanz MathyConstruction Industry Andrew.Hanz@mteservices.comChrisAbadie PineBluffS&G Industry abadie3522@icloud.comErvDukatz MathyConstruction Industry Ervin.Dukatz@mathy.comGerryHuber HeritageResearch Industry Gerald.huber@hrglab.comShaneBuchanan OldcastleMaterials Industry sbuchanan@oldcastlematerials.comAnneHolt OntarioMinistryofTransportation ProvincialAgency Anne.Holt@ontario.caRandyWest NCAT Research westran@auburn.edu

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� NeedforBalancedMixDesign� DefineBalancedMixDesign� ReviewFHWABalancedMixDesignTaskForceEfforts

¡CurrentStateAgencyPractice¡NCHRPProblemStatementDevelopment¡TechnicalBriefDevelopmentonBalancedMixDesign

NeedforBalancedMixDesign

1890•BarberAsphaltPavingCompany•Asphaltcement12to15%/Sand70to83%/Pulverizedcarboniteoflime5to15%

1905

•CliffordRichardson,NewYorkTestingCompany•Surfacesandmix:100%passingNo.10,15%passingNo.200,9to14%asphalt•Asphalticconcreteforlowerlayers,VMAterminologyused,2.2%moreVMAthancurrentdaymixesor~0.9%higherbindercontent

1920s

•HubbardFieldMethod(CharlesHubbardandFrederickField)•Sandasphaltdesign•30blow,6”diameterwithcompressiontest(performance)asphalticconcretedesign(ModifiedHFMethod)

1927

•FrancisHveem(Caltrans)•Surfaceareafactorsusedtodeterminebindercontent;Hveemstabilometerandcohesionmeterused•Airvoidsnotusedinitially,mixesgenerallydrierrelativetoothers,fatiguecrackinganissue

1943

•BruceMarshall,MississippiHighwayDepartment•RefinedHubbardFieldmethod,standardcompactionenergywithdrophammer•Initially,onlyusedairvoidsandVFA,VMAaddedin1962;stabilityandflowutilized

1993

• Superpave• Level1(volumetric)• Level2and3(performancebased,butnever implemented)

History

http://asphaltmagazine.com/history-of-asphalt-mix-design-in-north-america-part-2/

BINDER

CONTENT

LOWER

Stability

Stability+Durability

Stability+Durability

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� Designandoptimuminterchangeable?� NOTthesame

� Manydesignbindercontents,butonlyonetrulyoptimum

� Is4%airvoidstherighttargetforeverymix?

� Optimum:thebestbindercontentforperformancerequirements/needs,andultimatelyeconomics

� Goal:Closetooptimum

Designvs.Optimum

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OldcastleSurvey

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� Mostreporteddistressesarerelatedtomixdurability.

OldcastleSurveyQuestion:Withinthepast5years,whattypeofmixperformancerelateddistresshasbeenmostevidentinyourmixes?

~40companiesrespondingfrom~30states

q Durabilityrelatedperformanceissues.q Newmaterials,newmixes

q Polymersq MoreRAP/RASq Asphaltadditivesq Etc.

q Somestatesdoing“performancetesting”duringmixdesignand/orproductiontoensureperformance.q Thisisbalancedmixdesign.

BalancedMixDesign

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PendulumofPerformance

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DRY WET

OPT

IMUM

qDefineBalancedMixDesignqDeterminethecurrent“stateofpractice”ofBMD

qPresentapproaches/conceptsforimmediateuse

qRecommendfutureneeds(potentialresearch)toadvanceBMDapproaches

qDisseminateinformation

BMDTaskForceGoals

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BMDTaskForceWorkItems

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� Completed¡ DefinitionofBalancedMixDesign¡ SurveyofAgencyCurrentPractice

÷LaboratoryBalancedMixDesignProtocols÷FieldAcceptanceProtocols

¡ ResearchProblemStatement(RPS)SubmittedtoAASHTO)

� Current¡ FHWATechnicalBriefonBalancedMixDesign

÷Draftprepared,reviewedandbeingrevised

BalancedMixDesignDefinition

• “Asphaltmixdesignusingperformancetestsonappropriatelyconditionedspecimensthataddressmultiplemodesofdistresstakingintoconsiderationmixaging,traffic,climateandlocationwithinthepavementstructure.”

• Basically,itconsistsofdesigningthemixforanintendedapplication andservicerequirement.

BalancedMixDesignDefinition

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AgencyPracticesRelatedtoBMD

McCarthy,Callans,Quigley,andScott,IIINCHRPSynthesisNo.492

AgencyApproaches

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TimAschenbrener andKevinHall

VerifiedVolDesign

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q VolumetricDesignw/PerformanceVerification–Superpave withverifyingperformanceproperties;volumetricpropertieswouldhavetofallwithinexistingM323limits.ExampleStates:Illinois,Louisiana,NewJersey,Texas,Wisconsin

PerformanceModVolDesign

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q Performance-ModifiedVolumetricDesign–initialbindercontentsetbyM323/R35;perftestingmodifiesmixtureproportions-finalvolumetricpropertiescanbeoutsideexistingM323limits.ExampleState:California

PerformanceDesign

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q PerformanceDesign– conductasuiteofperformancetestsatvaryingbindercontentsandselectthebindercontentfromtheresults.Volumetrics determinedasthe‘laststep’andreported–norequirementsforM323limits.ExampleStates:NewJerseyw/draftapproach

BMDBasicExample

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• TexasDOT• Volumetricdesignconducted• HamburgWheelTracking

Test(HWTT)AASHTOT324• OverlayTester(OT)Tex-248-F• Threeasphaltbinder

contentsareused:optimum,optimum+0.5%,andoptimum-0.5%.

• TheHWTTspecimensareshort-termconditioned.

• TheOTspecimensarelong-termconditioned.

Withinthisacceptablerange(5.3to5.8percent),themixtureattheselectedasphaltcontentmustmeettheSuperpavevolumetriccriteria.

� Performancespacediagramsshowtheperformanceofamixrelatedtomultipletests

� Allowsthemixdesignertovisualizethemixperformanceandhowtoengineerthemixtoprovidethedesiredperformance

� Illustratestheimpactofvaryingmixfactorsonperformance.

PerformanceTestingtoUnderstandMixes

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From:Performance-SpaceDiagramfortheEvaluationofHighandLowTemperatureAsphaltMixturePerformance,Buttlaretal,AAPT2016

NeedforProductionVerification

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Optimize••Localmaterialsuse,recycle,additives,cost,appropriatebindercontent••Specificsite/enduse

Establish••Performancecriteria••Potentialsurrogatetestcorrelation••Volumetricpropertybaseline

Verify••QCtesting••Volumetricscomparisontobaseline••Surrogate(“Quick”)tests••Performancetestsat“x”frequency

ProductionDesign

BMDTFWorkProducts

• RPSpreparedinJune2016• AnticipatedResults

¡ 1)reviewofthestate-of-the-practiceofmixdesign

¡ 2)reviewstate-of-the-practiceforperformancetesting,

¡ 3)developRecommendedPracticeforBalancedMixtureDesign

¡ 4)developtrainingandimplementationplanandmaterialstomoveBMDaheadinStateHighwayAgencies(SHAs).

ResearchNeedStatement

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~1MilliontonsofHMAplacedeachday.• Criticaltoaddressmixdesignin

amorecomprehensivemanner

• FavorableresponseduringAugustSOM• Status:• Rankedhigh• DecisionnottoforwardtoRAC/SCOR• PursuingNCHRP20-07Projects• Morefullydevelopworkitems• Definestateofpractice

• ProbablynextyearbeforeitisforwardedtoRAC/SCOR

ResearchNeedStatement

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• TechBriefpreparedandreviewedbyfullETG.

• SubmittedtoFHWAforpublication.

FHWATechBrief- Draft

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WhatdoWedowithThis?BalancedMix Design

Opt.AC

SetVolumetrics

Table 11 Operational Tolerances

Description Test Method Allowable Difference Between Trial Batch and JMF1 Target

Allowable Difference from Current JMF Target

Individual % retained for #8 sieve and larger Tex-200-F or

Tex-236-F

Must be within master grading limits

in Table 8

±6.01

Individual % retained for sieves smaller than #8 and larger than #200 ±4.01

% passing the #200 sieve ±2.01

Asphalt binder content, % Tex-236-F ±0.5 ±0.5

Laboratory-molded density, % Tex-207-F ±1.0 ±1.5 VMA, %, min Tex-204-F Note2 Note2

1. When within these tolerances, mixture production gradations may fall outside the master grading limits; however, the % passing the #200 will be considered out of tolerance when outside the master grading limits.

2. Mixture is required to meet Table 8 requirements.

QCVolumetrics

QAVolumetricsQAPerformance

Testing

SomeDay

SetTolerances

� KeyFoundationalPointstoKeepinMind1. “UseWhatWorks”2. “EliminateWhatDoesn’t”3. “BeasSimpleasPossible,Be

Practical,andBeCorrect”

FinalThoughtsonMixDesign

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www.asphalttechnology.org/membership

At the 2016 AAPT Meeting:

§ Leading Edge Workshop: Cracking Tests§ 5 Presentations on Cracking Tests§ Symposium: Balanced Mix Design§ 5 Presentations on High RAP/RAS§ Implementation of Specifications§ Aging Behavior§ Forum Topic: World Asphalt Market

2017 Meeting: Newport Beach, CAMarch 19-27

WebinarSeriesDescriptionAAPTandtheAsphaltInstitutearehostingathree-partwebinarseriesforunderstandingoffatiguecrackingandacomprehensivereviewofthelaboratorymethodsforfatiguecrackingtests.

ComplimentaryforAAPTMembers!

ThoughtsandQuestions?

http://www.pennyauctionwatch.com/

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