SECTION II - Colorado Springs · PDF fileSection 4.0 Pavement Design ... Section 6.0...

ENGINEERING CRITERIA MANUAL

SECTION IIPavement Design

Criteria Manual


Page II

TableofContents

Section1.0 General .................................. 41.1 DesignReport. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Section2.0 FieldInvestigation .............................. 6

Section3.0 LaboratoryTesting.............................. 73.1 SoilClassification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73.2 Swell/ConsolidationTests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83.3 SubgradeSupportEvaluation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Section4.0 PavementDesign. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.1 EquivalentSingleAxleLoad(ESAL). . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.2 SubgradeSupportCharacterization............................114.3 FlexiblePavementStructuralSection . . . . . . . . . . . . . . . . . . . . . . . . . . .134.4 RigidPavementStructuralSection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144.5 MinimumPavementSections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154.6 AlternatePavementDesigns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Section5.0 PavementDesignReport . . . . . . . . . . . . . . . . . . . . . . . . . 185.1 ReportSubmittal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185.2 Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Section6.0 ConstructionAndMaterialSpecifications. . . . . . . . . . . . . . . . . . 256.1 HotMixAsphalt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .256.2 PortlandCementConcrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256.3 SubgradeandAggregateBaseCourse. . . . . . . . . . . . . . . . . . . . . . . . . . .256.4 MoistureTreatmentforExpansiveSoils. . . . . . . . . . . . . . . . . . . . . . . . . .256.5 ChemicallyStabilizedSubgrade ..............................276.6 MechanicallyStabilizedSubgrade. . . . . . . . . . . . . . . . . . . . . . . . . . . . .356.7 ProofRolling........................................386.8 WaterTesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Section7.0 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39


Page III

Tables

Table1 SubgradeClassificationTesting . . . . . . . . . . . . . . . . . . . . . . . . 7

Table2 SwellTestingFrequency. . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Table3 SubgradeStrengthEvaluation . . . . . . . . . . . . . . . . . . . . . . . . 8

Table4 CityStreetESALDefaultValues. . . . . . . . . . . . . . . . . . . . . . . .10

Table5 DepthOfMoistureTreatmentForExpansiveSoils . . . . . . . . . . . . . . .11

Table6 MaterialStrengthCoefficients. . . . . . . . . . . . . . . . . . . . . . . . .14

Table7 FlexiblePavementDesignParameters. . . . . . . . . . . . . . . . . . . . .14

Table8 RigidPavementDesignParameters . . . . . . . . . . . . . . . . . . . . . .15

Table9 MinimumPavementThicknesses(inches) . . . . . . . . . . . . . . . . . . .16

Table10 ScheduleforMinimumMaterialsSamplingandTesting(MoistureTreatedSoils) ............................27

Table11 ApprovedChemicalStabilizingAgents. . . . . . . . . . . . . . . . . . . .28

Table12 StabilizationMixDesignRequirements . . . . . . . . . . . . . . . . . . . .29

Table13 ConformitySpecifications. . . . . . . . . . . . . . . . . . . . . . . . . . .34

Table14 ScheduleforMinimumMaterialsSamplingandTesting(ChemicallyStabilizedSoils)..........................35

Table15 GeogridStructuralProperties. . . . . . . . . . . . . . . . . . . . . . . . .37

FiguresFigure1 Designchartforflexiblepavements,Arterials

AllCommercial&Industrial. . . . . . . . . . . . . . . . . . . . . . . . . .21Figure2 Designchartforflexiblepavements,Local&Collector

ExceptCommercial&Industrial. . . . . . . . . . . . . . . . . . . . . . . .22Figure3 Designchartforrigidpavements,CorrectionofEffectiveModulusofSubgrade

ReactionforLossofSupport . . . . . . . . . . . . . . . . . . . . . . . . .23Figure4 Designchartforrigidpavements,Arterials

AllCommercial&Industrial. . . . . . . . . . . . . . . . . . . . . . . . . .24


1.0 General

Thestructuraldesignofapavementsystemmustbedonewithaclearunderstandingofthefactorsthataffectthelifeandserviceabilityofthepavement.Therearemultiplefactorsindesignandconstructionofapavementsystem.ThisPavementDesignCriteriaManualaddressesthosefactorshavingasignificanteffectonthepavementlifeandserviceability.Theobjectiveistoobtainthebestqualitypavementsystemconsideringfactorssuchas:subgrade,trafficloads,pavementmaterial,futuremaintenanceandspecialconsiderationssuchasswellingorcollapsepronesoils,slopeinstabilitiesandfrostsusceptiblesoils.Thedesignmustbefoundeduponasoundtheoreticalandexperiencebasesincepublicmoniesareatriskandadirectfiduciaryresponsibilityexists.Thisdesignmanualassumesthatallofthepartsofthepavementsectionandsubgrade,trenchbackfill,hotmixasphalt,aggregatebasecourse,etc.areconstructedinaccordancewiththeCityEngineeringStandardEngineeringSpecificationsandthePikesPeakRegionAsphaltPavingSpecifications.

Thisdesignmethodologyisprescriptiveinnatureandrepresentstheminimumrequirementsofadesign.Thephilosophyistoprovideadesignsystemwhichiseasytounderstandanduse,andallowstheDesignEngineerflexibilitytoinvestigatealternatives.Alternatives,whenproposed,mustmeetminimumdesignrequirementsandhavesufficientdataandanalysestoallowCityEngineeringtoevaluatethealternatives.TheacceptanceofanydesignissolelyuptoCityEngineering.IntheeventCityEngineeringrejectsadesign,reasonsfortherejectionwillbeprovidedtotheDesignEngineer.

PavementdesignreportsandrecommendationsfornewsubdivisionstreetsaresubmittedtotheEngineeringDevelopmentReviewDivisionofCityEngineering.PavementdesignreportsandrecommendationsforCityEngineeringcapitalprojectsaresubmittedtoCityEngineering’sprojectengineer.

Thedesignbasispresentedinthisdocumentisbaseduponthe1993AmericanAssociationofStateHighwayandTransportationOfficials(AASHTO)DesignGuide.Theobjectiveistoprovidedesignparametersforlocalmaterialsandconditions,andtoprovideguidanceontheuseofAASHTOequations.Thepavementdesignsobtainedfromthisprocedureshouldhaveequallifeandserviceabilityprovidedtheminimummaterialspecificationsaremet,constructionrecommendationsarefollowed,andpropermaintenanceisprovided.Thedesignmethodologypresentedisnotmeanttopreventtheuseofalternativemethodsastechnologychangesandadditionalpavementsystemsdevelop.Furthermore,withCityEngineeringdiscretionandapproval,theColoradoDepartmentofTransportation2010PavementDesignManual,ormostcurrentversion,shallbeconsideredforaccepteddesignsolutionsformethodsnotcontainedinthisPavementDesignCriteriaManual.Throughoutthismanual,ASTMandapplicableAASHTO,orCDOTteststandardsapplyinterchangeably.


1.1 Design Report

TheDesignReportistoconsidertheconditionsafterdesignofthepavementalignmentandelevation,andafterthestreetiscuttoutilitygrade(utilitygrade,or“rough”grade,isdefinedaswithin+/-0.2’offinalgrade).Thenatureofsubgradesoilswhichexpandorcollapseduetowettingprovideuniquedesignproblemswhicharebestaddressedduringroughgradingoperations.APreliminaryGeotechnicalInvestigationofthestreetalignmentisappropriatewhenexpansiveorcollapsiblesoilconditionsarepresent,andwhenover-excavation,moisturetreatmentandre-compactionofthesubgradeduringmasssitegradingisexpectedtobeappropriate.Thepreliminaryinvestigationboringsmustbelocatedinbothcutandfillareas,andmustbeproperlysurveyedforbothhorizontalandverticallocation.BoringsmustextendbelowfinishsubgradeelevationsperboringdepthsasdiscussedinSection2.0.


2.0 Field Investigation

Thefieldinvestigationshouldbedesignedtoevaluatesubgradesoiltypes,determinegroundwaterlevelsthatmayimpactpavementperformance,andinvestigatesupportconditionsalongthealignment.Asaminimum:

1. Boringsshallbemadeatnotgreaterthan250-foothorizontalintervalsfor2-laneroadways;andnotgreaterthan250-footintervalsineachdirectionforroadwayswithmultiplelanesineachdirection.

2. Additionalboringsshallbemadetoinvestigateconditionssuchasfilleddrainageways,obviousdeflectingsubgrade,subgradematerialcolorchanges,unusualadjoiningvegetationorotherobservableconditionswhichcouldaffectpavementperformance.

3. Boringsaretobeaminimumof4feetindepthbelowdesignsubgrade,witheveryfourth(minimumofone)boring9 feetindepthbelowroughroadwaysubgradeelevation.

4. Allboringsshallbesampledusing“California”orthinwallShelbytubetypesamplersatdepthsof1footand4feetbelowroughcutsubgradeelevationforeachboring,andatadepthof9feetateveryfourthboring.TheblowsperfootorShelbypushedlengthandrecovery,boringnumber,andsampledescriptionshallbedocumented.Bulksamplesofmaterialsfoundintheupper4feetofthesubgradeshallbeobtainedfromeachboring.Shouldvaryingmaterialsbefoundintheupper4feet,samplesofeachmaterialtypeshallbeobtainedforclassification.

5. Boringlogsshallincludeadescriptionofsoiltypesencountered,depthsatwhichandtypesofsamplestaken,blowcounts,moistureconditions,freewaterandanomalousconditions.

6. Ifcircumstanceswarrant,testpitsareallowedprovidedthattheengineercanprovideadequateanalysisforpavementdesignpurposesmeetingCityEngineeringcriteria.


3.0 Laboratory Testing

Thepurposeofthelaboratorytestingprogramistoclassifysubgradematerialandevaluatesupportpropertiesandmoisturesensitivity(heave,collapse,softening)thatcanaffectlong-termpavementperformance.Testingprogramsconsistofclassificationtesting(i.e.,gradationanalysis,AtterbergLimitsandsulfatetests)andengineeringpropertiestesting(i.e.,swell/consolidation,R-value,unconfinedcompressivestrength,CaliforniaBearingRatio,andResilientModulusTests).

3.1 Soil Classification

Allsamplesofthesubgradesoilsobtainedshallbetestedtoevaluateclassificationusingthe

AASHTOsystem.TheminimumrequirementsareshowninTable1.

Table 1 Subgrade Classification Testing

AASHTOSoilClassification,AASHTOM145GroupIndexNumber Eachsoiltypeencounteredineachboring

NaturalMoisture/Density,AASHTOT265&AASHTOT204 EachdriveorShelbysample

MaximumDryDensityandOptimumMoistureContentT99/180

Bulksampleofmaterialgoverningpavementdesign

LiquidLimit,AASHTOT89 Eachsoiltypeobtainedineachboring

PlasticLimit,AASHTOT90 Eachsoiltypeobtainedineachboring

PercentPassingNo.200,AASHTOT11 Eachsoiltypeobtainedineachboring

GradationAnalysis,AASHTOT27 EachsampleofA-1toA-3soilsobtainedineachboring

SulfateTests,CDOT,CPL2103 1testforeach1,000linealfeetwhereA-6orA-7-6soilsarefound

SoilsshallbegroupedbasedupontheAASHTOclassificationsystemforeachbulkmaterialfoundintheupper4feetandtheGroupIndexcalculated.Whenagreaterthan7pointdisparityinGroupIndexisnoted,thesubgradesoilgroupsshallbesubdividedintotwoormoregroups.Thecontentofsoilgroupsshallbeplottedonaprojectdrawing.SoilswhichgovernthedesignshallbethosehavingthehighestAASHTOsoilclassification(i.e.,A-7-6toA-2-4),lowestsubgradesupportorhighestGroupIndex,withinthedesignlengthoftheroadway.Roadwaydesigncanbesubdividedbasedupontheextentofsubgradematerialsfoundalongtheroadwaylength.


3.2 Swell/Consolidation Tests

Cohesivematerials(A-4,A-5,A-6andA-7)shallbetestedtodetermineswellorconsolidationpotential.Testsshallberunon“California”orthinwallShelbytubesamplescollectedfrom1footbelowtheutilitygradeorsubgradeinaccordancewithASTMD4546ataverticalpressureof200psf.TestingfrequencyforthesematerialsshallbeinaccordancewithTable2.

Table 2 Swell Testing Frequency

Number of Borings Testing Frequency

Lessthan5 Eachboring

5-25 Minimum5samples

Greaterthan25 Minimum7samplesor1per5borings

Thetestresultsshallbeplottedandthepercentswell/consolidationandswellpressure(psf )shallbedeterminedandreported.Testresultswhicharesuspectedofbeingnotrepresentativeof“typical”conditionsshallnotbeconsideredinthedesignofthepavementbutshallbereported.Anydeletionofdatashallbejustifiedinthewrittenreport.Theswell/consolidationpotentialforagivensoilgroupshallbethecalculatedaverageofthegroup.

3.3 Subgrade Support Evaluation

Forthematerialgroupswhichgovernthedesign(asdeterminedinSection3.1)ofthepavementsystem,compactionandstrengthtestingshallbeperformedoncompositesamplesconstructedusingequalamountsofbulksampledmaterialswiththesameclassificationandGroupIndexrangespecificationinaccordancewithTable3.

Table 3 Subgrade Strength Evaluation

Subgrade Compaction and Strength Testing

UnconfinedCompressiveStrengthTestonremoldedsample,compactedat2%aboveProctoroptimummoisturecontentinaccordancewithAASHTOT99,orCaliforniaBearingRatioonremoldedsample(AASHTOT193)compactedat2%aboveProctoroptimummoisturecontent.orHveemStabilometer(R-value),AASHTOT190

ForallgroupsClassifiedasA-2-6,A-6,andA-7Forallgroups

StandardProctorCompaction,ASTMD698ModifiedProctorCompaction,AASHTOT180

ForgroupsclassifiedasA-2-6,A-6,andA-7.ForgroupsclassifiedasA-1,A-2,A-3,A-4,andA-5.


Thedesignsoilsupportvalueshallbedeterminedtobethelowestvalueobtainedfromthetesting.IntheeventtheDesignEngineerelectstoremoveandreplacethelowestsupportvaluetoaminimumdepthof2feetbelowfinishsubgrade,thesupportvalueofthereplacementfillcanbeused.Technicaljustification(calculations)fortheremovalandreplacementshallbeprovidedinthereport.


4.0 Pavement Design

Thedesignmethodologyisbaseduponthe1993AASHTODesignGuideequationsandconsidersTrafficandSubgradeResilientModulusastheprimaryvariables.TrafficloadingrequirementsarepresentedinSection4.1.TheSubgradeResilientModulusandswell/consolidationanalysisshallbedeterminedinaccordancewithSection4.2ThedesignequationsforflexibleandrigidpavementsarepresentedinSection4.3and4.4.Alternativeswillbeconsideredwithadvancesinpavementdesignmethodsandpavingmaterialchanges.AnydeviationfromguidelinespresentedinthisdocumentmustbetechnicallyjustifiedandapprovedbyCityEngineering.

4.1 Equivalent Single Axle Load (ESAL)

Oneofthefactorsusedinpavementdesignistheloadingoftrafficontheroadway.Thisisacombinationofthevolumeoftrafficandtheweightofthevehiclesonthestreet.Thisfactorisdescribedintermsof18,000-poundEquivalentSingleAxleLoadsorESAL’s.ThecalculationofESAL’sisbasedonthefollowinginformation:

- ADT

- Lanedistribution

- Truckvolumes

- Truckweightsandaxleconfigurations

Sincethisinformationisnotreadilyavailableforallstreets,thismanualprovidesdefaultESALvaluesforCitystreetclassificationsandCity-widetruckvolumeestimates.TheESALvaluestobeusedforstreetclassificationsareshowninTable4.

PavementdesigncanbecompletedusingaroadwayspecificESALvalue.ESALcanbecalculatedusingthetechniquedescribedintheColoradoDepartmentofTransportation(CDOT)mostrecentPavementDesignmanual.Thecalculations,inputdata,andanyassumptionsmustbereviewedandacceptedbyCityEngineering.

Table 4 City Street ESAL Default Values

20-year ESAL Flexible Pavement Rigid Pavement

Freeway/Expressway 8,000,000 11,000,000

MajorArterial 4,500,000 6,250,000

MinorArterial 2,500,000 3,250,000

IndustrialStreet/CommercialFrontage 1,250,000 1,750,000

Major/MinorCollector 200,000 200,000

Local 50,000 50,000

Theseareone-directionalandper-laneESALvalueswhichmaynotbereducedfordirectionaltravelorlanedistribution.


4.2 Subgrade Support Characterization

Subgradecharacterizationconsistsofevaluatingsubgradeandlong-termsupportvalues.Thedegreeofmoisturesensitivityanddeflectionsensitivityisusedtoevaluatethedepthofmoisturetreatmentappropriatetoreducethedeflectionatthesurfaceofthecompletedpavementsystem.ThesupportvalueisexpressedintheformofaResilientModulusasdeterminedfromunconfinedcompressivestrength,R-value,orCBRtesting.

1. Expansive Subgrade-Testsperformedtodetermineswell(expansion)potentialinaccordancewithSection3.2shallbeaveragedforeachsoilgroup.Forthehighestaverageswell,thedepthofmoisturetreatmentshallbedeterminedinaccordancewithTable5.Usingengineeringjudgment,locallydifferingvaluesshallbeaddressedinthetextofthereportundertheappropriatesubgradediscussionsection.

Table 5 Depth Of Moisture Treatment For Expansive Soils

Swell % at 200 psfSubgrade SoilLiner Samples

Depth of Moisture Treatment (feet)

Non-Arterials Arterials

<2 -- --

2to3 -- 2

3to4 -- 4

4to5 2 5

5to6 3 6

6to8 4 6

8to10 5 6

Greaterthan10 6 6

Moisturetreatmentistheprocessofremovingthesoil,addingmoistureuntilthesoilmoisturecontentisbetween1and3percentaboveoptimumasdeterminedbyAASHTOT99(ASTMD698),andcompactedtoatleast95percentofmaximumStandardProctordensity.SoilsrequiringmoisturetreatmentperTable5willrequireastabilizedsubgradeperSection4.2.2.Moisturetreatmentshallextendtothebackofcurbasaminimum.

2. Subgrade Stabilization-Subgradesoilstreatedtohavehighmoisturecontentstypicallyhavelowsupportvaluesandwillbesoftandyieldingduringpaving.Stabilizationofatleasttheupper12inchesbychemicalormechanicalmethodswillbenecessary.ThisdepthincludesanyapprovedChemicallyTreatedSubgradesection(CTS).Thedepthoftreatmenthastobedeterminedbythedesignengineerinthedesignreport,orasanaddendumtothereport,basedupontheactualfieldconditions.Subgradestabilizationshallextendtothebackofcurbasaminimum.


a. ChemicalStabilization-Chemicalstabilizingagentsincludelime,flyash,combinationsoflime/flyash,andlime/Portlandcement.OtheragentsorcombinationscanbeusedwithapprovalbyCityEngineeringandprovidedthemixdesignrequirementsaresatisfied.Laboratorymixdesignsshallmeetthefollowingcriteria:

1. ForLimetreatmentthepHshallbeequaltoorhigherthan12.3beforecompaction(notrequiredwhereswellislessthan4percent)

2. UnconfinedCompressiveStrengthbetween160psiand700psi(ASTM2166)

3. Swelllessthanonepercentat200psf(ASTMD4546)

Whenlimeisused,PlasticityIndexistobereportedfrominitialtofinalconstructiontoallinterestedparties(e.g.,StabilizationContractor,GeotechnicalEngineerandCityInspector)andshallnotbeusedforacceptancepurposes.Thedesignstabilizingagentpercentageasdeterminedbythedesignershallbeincreasedby1.0percentinthefieldtoaccountforwaste,inertmaterials,andconstructionvariability.

Ifwatersolublesulfatecontentsexceed0.2percent,thetreatmentshallbeaccomplishedusingadoubleapplicationmethod.AdoubleapplicationmethodconsistsofaninitialtreatmentofLimeandallowingittomellowforaminimumperiodof7days(withconstantwetting).Afterthemellowperiod,thesubgradeshouldbemechanicallymixedpriortoapplyingtheremainingpercentageofchemicalstabilizer(Lime,FlyAshorCement).Thisshallbepresentedanddiscussedinthedesignreport.AllchemicalstabilizationshallbeperformedinaccordancewithSection6.5.

b. MechanicalStabilization - Soft,yieldingsoilsmaybestabilizedmechanicallyusinggeogridsinconjunctionwithaggregatebasecourseorrecycledconcretetoprovideastableconstructionplatform.AllmechanicalstabilizationshallbeperformedinaccordancewithSection6.6.

3. Resilient Modulus-Subgradesupportcharacteristicsusingthe1993AASHTOdesignmethodologyconsidertheResilientModulus(Mr).EquipmenttodirectlydeterminetheResilientModulusmaynotbeavailabletosomelocalfirms.AseriesofcorrelationsandalternativeequationsareprovidedtoaidfirmsthatdonothavetheappropriateequipmenttoestimatethedesignMr.equationstoestimatevaluesusingR-valuefornon-cohesivesubgradematerials,amodifiedunconfinedcompressivestrengthprocedureorCBRforcohesivesubgradematerialsareincludedwiththisdocument.ThesubgradestrengthcharacteristicsshallbeevaluatedinaccordancewiththerequirementsofSection3.0LaboratoryTesting.ThesevaluescanbeconvertedintoResilientModulususingthefollowingequations:


UnconfinedCompressiveStrength

(A-2-6 soils) Mr= 2.23 (qu) (.75)

(A-6 soils) Mr= 2.15 (qu) (.75)

(A-7-6 soils) Mr= 3.13 (qu) (.75)

(Claystone) Mr= 1.68 (qu) (.75)

Where qu = unconfined compressive strength in psf

CaliforniaBearingRatio

Mr= (CBR) x 1500

HveemStabilometer(RValue)

Mr= 10

Where S = [(R-value -5) / 11.29] + 3

4.3 Flexible Pavement Structural Section

Thethicknessofthepavementsectionshallbedeterminedusingthedesigntraffic20-year,18-kipESAL’sobtainedfromSection4.1,theResilientModulusobtainedfromSection4.2.3andthedepthofmoisturetreatmentandstabilizationobtainedfromSection4.2.1and4.2.2.

TheStructuralNumber(SN)shallbedeterminedusingtheAASHTO1993designmethodologyorusingthedesignnomographsprovidedinFigure1withtheinputparameterspresentedinTable6.UsingstrengthcoefficientsprovidedinTable7,calculatethethicknessofthevariouspavementlayersbythefollowingformula:

SN = a1(D1) + a2(D2) + . . . + an(Dn)

Where:

a1 = Strength coefficient for HMA

a2, a3, a4…an = Strength coefficient for lower layers

D1 = Thickness of HMA

D2 , D3, D4…Dn = Thickness of additional layers

S+18.726.24


Table 6 Material Strength Coefficients

Material Coefficient (a)

HotMixAsphalt(HMA) 0.44

ExistingHotMixAsphalt 0.241

AggregateBaseCourse/RecycledConcreteBase 0.12

ExistingAggregateBaseCourse/RecycledConcreteBase 0.10

GranularSub-base(R=50+,CBR=15+) 0.07

ChemicallyTreatedSubgrade(ConstructedinaccordancewithSection6.5) 0.14

Note1:Maximumvalueunlesssupportedbytesting

Table 7 Flexible Pavement Design Parameters

Input Value

Reliability(R)

95%forarterialsandallcommercialfrontageandindustrialroadways90%forcollectors85%forlocalroadways80%forcul-de-sacs

StandardDeviation(So) 0.44forflexiblepavements

InitialServiceability=4.5ServiceabilityLoss(ΔPSI)

2.5Locals,collectors,privatedrives,parkinglotsandpublicalleys2.0Arterialsandallcommercialfrontageandindustrialroadways

4.4 Rigid Pavement Structural Section

ThethicknessofthepavementsectionshallbedeterminedusingthetrafficESAL’sobtainedfromSection4.1,ak-value,thedepthofmoisturetreatment,andstabilizationobtainedfromSection4.2.1and4.2.2.Forrigidpavementdesign,theResilientModulus(Mrinpsi)mustbeconvertedtoaModulusofSubgradeReaction(k-Valueinpci)usingthefollowingformula.

k-value (pci) = Resilient Modulus (psi) / 19.4

Theeffectivek-valuecanbedeterminedbycorrectingforLossofSupport(LS)(Figure1)withthefollowingassumptions:

LS = 0 for concrete over an existing pavement

LS = 1.0 for Chemically Treated Subgrades

LS = 2.0 – 2.5 for Natural Subgrade Materials


ThedesignthicknessshallbedeterminedusingtheAASHTO1993designmethodologyorusingthedesignnomographsprovidedinFigure3and4withtheinputparameterspresentedinTable8.

Table 8 Rigid Pavement Design Parameters

Input Value

Reliability(R)

95%forarterialsandallcommercialfrontageandindustrialroadways90%forcollectors85%forlocalroadways80%forcul-de-sacs

StandardDeviation(So) 0.34forrigidpavements

ConcreteElasticModulus(Ec) 3,500,000psi

ConcreteModulusofRupture(S’c) 650psi

LoadTransferCoefficient(J)2.8fullreinforcement3.6iftiedintocurb&gutter4.2noreinforcement

InitialServiceability=4.5ServiceabilityLoss(ΔPSI)

2.5Local,collectors,privatedrives,parkinglotsandpublicalleys2.0Arterialsandallcommercialfrontageandindustrialroadways

Jointspacing,dowelingandtiebarsshallbeinaccordancewithAmericanConcretePavementAssociationrecommendationscontainedinDesignandConstructionofJointsforConcreteStreets.Dowelsarerequiredforindustrialandarterialstreetsforlongitudinalandexpansionjoints.

4.5 Minimum Pavement Sections

IfthecalculatedpavementsectionsindicatesectionsthinnerthantheMinimumPavementSectionsshownbelowinTable4.5.1,theMinimumPavementSectionsshallgovern.TheCityEngineerpreferstheuseofflexiblepavementdesignedasacompositesectionofhotmixasphaltoveraggregatebasecourse.Fulldepthpavementsections(flexibleorrigid)areallowedsubjecttosufficientjustificationoverchemicallytreatedsubgrade,orsuitablesubgradeasdefinedherein.Fulldepthpavementisnotallowedovermechanicallystabilizedsubgrade.Certainverysandysubgradeconditionsmayrequireapplyinganon-structuralcoveringofaggregatebasecourseforconstructabilitytosupportthepavingequipment.TheCityEngineermayincreasetheminimumpavementsectionatanylocationifconditionswarrant.FollowinginTable9aretheminimumpavementthicknessesrequiredbyCityEngineering:


Table 9 Minimum Pavement Thicknesses (inches)

Flexible Pavement Rigid Pavement

Classification HMA + ABC3 HMA + CTS2 HMA1 PCCP1

MajorArterial 5”+12” 5”+12” 9” 8”

MinorArterial 4+12” 4”+12” 8” 8”

MajorResidentialCollector(4lane) 4”+8” 4”+8” 5” 6”

MajorResidentialCollector(2lane) 4”+8” 4”+8” 6” 6”

MinorResidentialCollector 4”+6” 4”+6” 5” 6”

Residential 4”+6” 4”+6” 5” 6”

MinorResidential 4”+6” 4”+6” 5” 6”

HillsideMinorResidential 4”+6” 4”+6” 5” 6”

Industrial/Commercial(4lane) 4”+12” 4”+12” 8” 6”

Industrial/Commercial(2lane) 4”+12” 4”+12” 8” 6”

FrontageRoad 4”+6” 4”+6” 5” 6”

NOTES: 1.Fulldepthpavement(asphalticconcrete)isonlyallowedoverchemicallytreatedorsuitablesubgrade.Fulldepthpavementisnotallowedovermechanicallystabilizedexpansivesubgrade.Seesection4.5.2.CTSsectionasapprovedbytheCity3.TheminimumthicknessofABCshallbesixinchesinanyapplication

ABBREVIATIONS: HMA=HotMixAsphalt ABC=AggregateBaseCourse CTS=ChemicallyTreatedSubgrade PCCP=PortlandCementConcretePavement

4.6 Alternate Pavement Designs

CityEngineeringunderstandstheneedtoconsideremergingtechnologiesinpavementdesign.Inlightofthis,anyalternatepavementdesignwillbereviewedandconsideredwithrespecttothefollowingcriteria:

- Initialconstructioncost

- Lifecyclecost

- Constructiondelayandimpact

- Facilitymaintenanceandeaseofrepair

- Pavementnoise,smoothness

- Industrycapacityandlocalcontractorcapability

- Specialdesignprovisionssuchasedgedrainsbehindthecurbs1tointerceptmoisturefromadjoiningdevelopmentandpreventitfromadverselyaffectingtheroadsubgradeandpavingsection.


CityEngineeringreservestherighttomakethepavementtypeselectionusingtheseand/orothercriteriaonCityfundedprojects.

1Special Drainage Considerations: Thedesignengineershouldanticipatethefuturedevelopedconditionofthelandadjacenttotheroadwaywhenmakingthepavingdesignrecommendations.Evenwhennoshallowgroundwaterispresentinthepre-developedconditionitisexpectedthatcertainlandusessuchassinglefamilyhomesandprojectswithirrigatedlandscapingpresentthepossibilityofwaterenteringtheroadsubgradeandadverselyaffectingtheperformanceandlongevityofthepavement.Cityforceshavetoinstallretrofitunderdrainsystemsinmanystreetstomitigatethesekindsofproblems.AppropriaterecommendationsanddesignfeaturestostopwaterfrominfiltratingintothepavementsectionwillreceivepositiveresponsefromCityEngineering.


5.0 Pavement Design Report

Allpavementdesignreportsshallbepreparedbyorunderthesupervisionof,andstampedandsignedby,aProfessionalEngineerlicensedintheStateofColoradoandpracticingasaGeotechnicalEngineer.

5.1 Report Submittal

DesignreportsshallbesubmittedtoCityEngineering.PavementdesignreportsfornewsubdivisionstreetsaresubmittedtotheEngineeringDevelopmentReviewDivisionofCityEngineering.PavementdesignreportsforCityEngineeringcapitalprojectsaresubmittedtoCityEngineering’sprojectengineer.Allreportsshallcontainthefollowingitems:

- Descriptionoftheareaoftheprojectincludingthelocationlanduse,surfaceconditions,topography,sitegrading,extentofsitedevelopmentatthetimeofinvestigation,vegetation,andanyunusualsurfacefeatures.

- ListingofthesamplingandtestingtechniquesandappropriateAASHTOorASTMdesignations.

- TableshowingAASHTO,USCSandGroupIndexoftheindividualsubgradesamplesfoundwithinthedrillingdepthsandofthegroupswhichgovernthepavementdesign.

- Subgradesupporttestingsectionsshallincludegraphsofmoisture/densityrelationtests,R-values,CBRtests,unconfinedcompressivestrength,swell/consolidationtestsandothertestsdeemedtobeapplicablefortheconditionsfoundperformed.Thesubgrade-supporttestresultsshallbeshownalongwiththeresultingcalculatedResilientModulusork-Valueandtheequationsusedtodeterminethevalue.

- Wheremoisturesensitivesubgradesoilsoccur,thedepthofmoisturetreatmentandsubgradestabilizationotherthanthedepthdeterminedfromSection4.2.1shallbediscussedandtheanalysisshown.

- Wheretreatmentisrequiredduetoexpansivesoils(Section4.2.1),astabilizedsubgradeisrequired(Section4.2.2)andareportshalldeterminethestabilizingagenttobeused.Anystabilizingagentsnotlistedmustbepre-approvedbyCityEngineering.Specialstabilizationtechniquesrequiredduetohighwatersolublesulfatecontentsorotherconditionsshallbepresented.Wheresoilscontainsolublesulfatesinconcentrationsgreaterthan0.2percent,adiscussiononadoubleapplicationmethodandsulfateresistantconcreteshallbepresented.Shouldanyofthesesoilsbestabilized,specialconstructionprecautionsshallbepresented(i.e.,stagedconstruction).

- ThedesigntrafficintermsofESAL’sshallbepresentedonafigureanddiscussedinthedesignreport,includingthesourceoftrafficinformation.


- Designpavementthicknessesincludinghotmixasphalt,Portlandcementconcreteorcompositesectionsshallbeshownonafigureforthevariousstreetsections.Ifcomputersoftwareisusedtodevelopsolutions,theprintoutfromthesoftwareshallbeincludedinthereport.Ifnomographsareused,theyshallbeincludedinthedesignreportforeachsoilgroupandtrafficloadingcondition.

- Adiscussionofdesignandconstructionconcernsshallbepresented,followedbyspecificrecommendationstomitigatetheconcerns.Factorssuchas,butnotlimitedto,swellingheave,frostheave,collapsingsoils,difficultexcavations,steeplydippingbedrock,organicsoils,highwatertable,medianlandscaping,lowdensity,collapsepronesoils,orutilitytrenchsettlementeffectsmustbepresented,discussed,andmitigationrecommendationspresented.

- Wheretwominorarterialorhigherclassificationstreetsintersect,thedesignshouldconsiderthecombinedtrafficvolumes.TheuseofPortlandCementConcretePavementathightrafficvolumeintersectionsmaybedeemednecessarybyCityEngineering.Highvolumeasphalticconcretemayalsobeappropriate.CityEngineeringwilldeterminetheextentofthe“highvolume”intersectiontreatments.

- Thereportshallincludeadiscussionofmaterialrequirementstomeetthedesignassumptions.ThereportshallrefertoappropriateCityofColoradoSpringsandPikesPeakRegionmaterialandconstructionspecifications.Hotmixasphaltdesignrecommendations,inaccordancewiththeCityofColoradoSpringsandthePikesPeakRegionAsphaltPavingSpecifications,shallalsobeincluded.CDOTrequirementsmayalsoapplyforhightrafficintersections.

- Additionalconcernswithrespecttodesign,construction,maintenance,andotherprojectaspectsshouldbepresentedanddiscussed.

- Forsubdivisionstreets,anyissuesidentifiedintheGeologicHazardStudyrelatingtosoilstabilityorspecialdesignrequirementsmustbediscussed.

- ReferenceList

5.2 Figures

Toevaluatethedesign,figuresarenecessarytopresentinformationanddesigndata.Allreportsmusthavethefollowing:

1. Project location including:

a. Avicinityfigureshowingtheprojectlocationusingexistinglandmarks,roadways.

b. LocationofexploratoryboringsandtheestimatedextentofsubgradesoiltypesbysoilgroupsandAASHTOclassifications.

2. Graphical representation of exploratory borings:

a. GraphicalboringlogsshallberepresentedusingAASHTOclassificationsformaterials.Bedrockshallberepresentedinaccordancewithlocalpractice,i.e.,sandstone,claystone,interbeddedbedrock,weatheredclaystone.

b. Theboringlogsshallalsoprovidethefollowing:


1. Samplingdepthsandlength,includingblowcount,pushdepth,andrecovery

2. Moisturecontent,drydensity,percentswell/consolidation–undera200psfpressure

3. AtterbergLimits(liquidlimit,plasticityindex)

4. PercentpassingtheNo.200sieve

c. Figuresshowingswell/consolidation,moisture/densityrelations,unconfinedcompressivestrength,andresultsofHveem/stabilizationorCBRtesting.

d. Designpavementsectionalternativesandspecialalternatives

3. Recommended Pavement System:

a. Thedesignalternatives,baseduponengineering,shallbepresentedona“RecommendedPavementAlternatives”figure,illustratingtheextentofeachalternativepavementsectionalongwithalegenddescribingeachpavementalternative,thedesignESAL,andthesubgradegroupusedforthedesign.

b. Specialconsiderationssuchassoftsoils,organicmaterials,treatmentsshallbepresentedonthe“RecommendedPavementAlternatives”figure.

c. Structuressuchasbridges,boxculverts,interchanges,andturnlanesshallbeshownonallsitefigures.

d. Wherelaneshavedifferentpavementsections,thevariationsshallbeclearlyshownonthe“RecommendedPavementAlternatives”figure.


Figure 1 Design chart for flexible pavements


Figure 2 Design chart for rigid pavements Local & Collector


Figure 3 Design chart for rigid pavements


Figure 4 Design chart for rigid pavements


6.0 Construction And Material Specifications

Theintentistospecifymaterials,equipment,methodsandstandardstobeusedfortheconstructionofpavementsystemsasindicatedontheplans.Thedesignintentistoconstructapavementwithadequatethicknessandqualitytoprovideaserviceablelifeofatleast20years.Allworkmanshipandmaterialsshallbeinaccordancewiththerequirementsofthesespecificationsandspecialprovisions,andinconformitywiththelines,grades,quantitiesandtypicalcrosssectionsshownontheplansorasdirectedbyCityEngineering.

6.1 Hot Mix Asphalt

AllhotmixasphaltmustmeetthematerialspecificationsandconstructionstandardspresentedinthecurrentversionofthePikesPeakRegionAsphaltPavingSpecifications.

6.2 Portland Cement Concrete

AllPortlandcementconcretemustmeetthematerialspecificationsandconstructionstandardspresentedinthecurrentversionoftheCityofColoradoSpringsCityEngineeringStandardSpecificationsManual.

6.3 Subgrade and Aggregate Base Course

Allpreparedsubgradeandaggregatebasecourse,includingrecycledconcrete,mustmeetthematerialspecificationsandconstructionstandardspresentedinthecurrentversionoftheCityofColoradoSpringsCityEngineeringStandardSpecificationsManual.Aggregatebasecourseshallextendtothebackofcurbasaminimum.

6.4 Moisture Treatment for Expansive Soils

Thisworkconsistsofremoving,moistureconditioning,replacing,compaction,andshapingtheexistingexpansivesubgradewithmoistureanddensitycontroltotheextentshownontheplans.Thepurposeistoprovideazoneoflowswelling,strainabsorbingmaterialbetweentheexpansivesubgradeandthepavementsection.Moisturetreatmentshallextendtothebackofcurbasaminimum.Thedepthofremovalandreplacementwithmoisturetreatedsubgradeshallbeconsistentwiththeplansregardlessofcut,fillorbackfill.


1. Equipment - Thecontractorshallprovideequipmentingoodoperatingconditionthatisspecificallydesignedandmanufacturedforthepurposeofexcavating,hauling,mixing,watering,levelingandcompactingsubgradematerials.Mixingandwateringequipmentshallbecapableofachievingauniformmoisturecontentwithoutwetordryzones.Compactionequipmentshallbeadequatelydesignedtoobtaincompactionrequirementswithoutadverseshoving,rutting,displacementorlooseningofsubgradematerial.Theequipmentshallbeavailabletoperformtheworkspecifiedwithinthetimeframesrequiredandtobecoordinatedwithotheractivities.Theequipmentshallbeoperatedbyskilledworkmanatanormalproductionrateforthespecifiedtypeofwork.

Allequipmentandmachineryshallbekeptingoodworkingorder,freeofleaksandproperlymuffled.Alltaxes,licensesandfeesshallhavebeenpaidandproperlicensesandpermitsshallbepostedasrequiredbylaw.

2. Construction Methods

a. Compaction-Theexistingsubgradeshallberemoved,uniformlymoisturetreated,mixed,replaced,andcompacted.Eachlayershallbecompactedtoatleast95percentStandardProctordensityasdeterminedbyAASHTOT99at1to3percentaboveoptimummoisturecontent.Thethicknessoflayers,priortocompactions,shalldependuponthetypeofsprinkling,mixingandcompactingequipmentused.Moisture/densitytestsshouldbeperformedevery250linearfeet,alternatinglanes,toverifysubgradedensitymeetsspecifications.

Aftereachlayeroffilliscomplete,testsmustbemadetoconfirmmoisturecontentandrequiredcompaction.Whenthematerialfailstomeetthecompactionormoisturerequirementsorshouldthemateriallosetherequiredcompactionormoistureorfinishbeforethenextcourseisplacedortheprojectisaccepted,thelayershallbeprocessed.Reprocessingshallbedoneatthecontractor’sexpense.

Thecontractormayberequiredtoexcavateanareaofthelayerinordertofacilitatethetakingofdensitytests.Replacementandcompactionoftheremovedmaterialintheareashallbeatthecontractor’sexpense.

b. SubgradeStabilization-Moisturetreatmentwillleaveasoftyieldingsubgradeunsuitableforpaving.StabilizationinaccordancewithItem4.2.2,SubgradeStabilization,shallbeperformedtothedepthsandlimitsshownontheplans.

3. Tolerances

a. GradeTolerances-Anydeviationinexcessof1/2inchincrosssectionand1/2inchin10feetmeasuredlongitudinallyshallbecorrectedbyloosening,addingorremovingthematerial,reshapingandre-compactingbysprinklingandrolling.Deviationsinexcessofthistoleranceshallbecorrectedbythecontractor,atthecontractor’sexpense,inamannersatisfactorytoCityEngineering.

b. CompactionTolerances-Compactionbelowthespecifiedminimumshallbecorrectedbyre-compaction.Inadequatecompactionshallbecorrectedbythecontractor,atthecontractor’sexpense.


c. MoistureTolerances-Anylossofmoisturebelowthesetlimitsshallbecorrectedbymoistureconditioningandre-compaction.Lossofmoistureshallbecorrectedbythecontractor,atthecontractor’sexpense.

4. Testing and Inspection

a. TestingofmoisturetreatedsoilsshallbeperformedinaccordancewithTable10.

Table 10 Schedule for Minimum Materials Sampling and Testing (Moisture Treated Soils)

Test Type Test Standard Minimum Frequency of Tests

InPlaceSoilDensityAndMoistureContent

AASHTOT191ASTMD2167AASHTOT238ASTMD2216AASHTOT239

Onetestforeach250lanefeet(notlessthanonetestperday).

LiquidLimit AASHTOT89 Onetestpersoiltype

PlasticLimit AASHTOT90 Onetestpersoiltype

Moisture-DensityRelationships

AASHTOT99AASHTOT180 Onetestpersoiltype

6.5 Chemically Stabilized Subgrade

Thisworkconsistsofthecontractorconstructingoneormorecoursesofamixtureofsubgradesoil,approvedstabilizingagentandwaterinsubstantialconformitywiththedesignline,grades,thicknesses,andtypicalcrosssectionsshownontheapprovedplansandtheapprovedpavementthicknessdesign.Purpose - Thepurposeoftheworkshallbetoprovideastructuralsectiononwhichpavingmaterialscanbeplacedandtomeetdesignspecifications,whileatthesametime,protectingtheunderlyingmoisture-treatedsubgradesoils.Subgradestabilizationshallextendtothebackofcurbasaminimum.Thisspecificationcanalsobeappliedtoachieveastabilizedpavingplatformwithoutstructuralbenefits.

1. Materials

a. StabilizingAgents-Thepre-approvedstabilizingagentsarelistedinTable11.Variouscombinationsofthesematerialsmayalsobeused,subjecttoasuitablemixdesign.OtheragentsmaybeusedwithpriorwrittenapprovalofCityEngineering.


Table 11 Approved Chemical Stabilizing Agents

Pre-Approved Stabilizing Agents

Agents Must conform to requirements of

Lime ASTM C977,C110

FlyAsh(CandF) ASTM C618

CementKilnDust ASTM D5050

PortlandCement ASTM C114

High-calciumquicklimeshallconformtotherequirementsofASTMC977andrateofslakingtestshallproduceatemperatureriseof20°Cin30secondsand35°Cin3minutesperASTMC110.Dolomiticquicklime,magnesiaquicklimewithmagnesiumoxidecontentsinexcessof4percentorcarbonatedhydratedlime,shallnotbeused.High-calciumquicklimemustbeappliedinslurry.

FlyashmayconsistofClassCorClassF.ClassFflyashshallonlybeallowedinconjunctionwithlimeorothercementitiousstabilizingagents.

Allstabilizingagentsshallcomefromthesamesourceasusedinthedesign.Ifthesourceischanged,anewdesignmustbesubmittedtoCityEngineeringforapproval.Eachlotofstabilizingagentfurnishedshallhavethesupplier’scertificateofcompliance.

b. Water-Waterusedformixingorcuringshouldbefromapotablesource.Intheeventpotablewaterisnotused,non-potablewatershallbetestedinaccordancewithandmeettherequirementsofAASHTOT26andusedinthemixdesign.

c. Subgrade-Thesubgradematerialtobestabilizedshallbefreeofroots,sod,weeds,wood,constructiondebris,ice,snow,orotherfrozenmaterials,deleteriousmatter,andstoneslargerthan3inchesinsize.Materialinthestabilizedzoneshallhaveawatersolublesulfatecontentoflessthan0.2percentasperCPL2103,MethodB.Ifthesubgradesoilshaveasolublesulfatecontentexceeding0.2percent,themixdesignshalladdressthespecificmethodologyusedtopreventadverseeffectsofsulfatereactions(e.g.heavingsubgrade,crackedpavement).

2. Equipment - AllequipmentshallbesubjecttoapprovalbyCityEngineering.Allequipmentandmachineryshallbekeptingoodworkingorder,freeofleaksandproperlymuffled.

a. DryApplicationEquipment-Equipmentforspreadingdrystabilizingagentshallbeofanapprovedscrew-typespreaderbox,mixer,orothersemi-enclosedequipmentwhichisequippedwithameteringdevice.Spreadingofstabilizingagentsbyaggregatespreadersormotor-graderswillnotbeallowed.

b. SlurryApplicationEquipment-Adistributorortruckapplicatorshallbeusedandbecapableofcontinuousagitationtokeeptheslurrymixtureuniform.Theapplicatorshallbecapableofuniformlymeteringthestabilizingagentduringapplication.


c. MixingEquipment-Mixingequipmentshallbeofsufficientsizetoadequatelymixthestabilizingagentintothesoilandtopulverizethemixture.Thesizeofthemixershallbeadequatetomixandpulverizethemixturetoaminimumdepthof12inchesinasinglepass.Blades,discs,andsimilarequipmentarenotallowedwithoutpriorwrittenapprovalofCityEngineering.

d. CompactionEquipment-Compactionequipmentshallbeingoodworkingorderandofsufficientsizeandeffectiveforcetoachievetherequiredcompactiveeffort.

3. Construction Submittals - Atleast15dayspriortocommencingstabilizationwork,thecontractorshallfurnishthefollowinginformationtoCityEngineering:

- Thesourceandsupplierofstabilizingagentandcertifications,includingpurityofstabilizingagent,fromthemanufacturer’stestingagencyindicatingthatthestabilizingagentmeetstheappropriaterequirements.

- Descriptionoftheproposedconstructionequipment,constructionmethods,expectedproductionratesandplannedsequenceofconstruction.

- AmixdesigngivingtheWaterSolubleSulfatetestresultspercentageofstabilizingagent,sourceoftheagent,propertiesandanyspecialconsiderations.

Foreachday’swork,thecontractorshallfurnishthefollowinginformationtotheCityEngineeringInspectorbythefollowingday:

- Certifiedtruckweightticketsofstabilizingagent,deliveredorusedatthesite.

- Asummaryoftheamountofstabilizingagentusedeachday,areasstabilizedandfirstmixed,areassecondmixedandcompacted,andareaswithcuringcompleted.

- Priortopaving,finalinplacesoilpropertiesperTable6.5.11.

4. Stabilized Mix Design

MixdesignsshallbeperformedunderthesupervisionofandsignedbyaProfessionalEngineerlicensedtopracticeintheStateofColoradopracticingasageotechnicalengineer.MixdesignshallcomplywiththerequirementsofTable12

Table 12 Stabilization Mix Design Requirements

Stabilization Mix Design Requirements

Stabilization Agent

Minimum pH

(Notes 1 & 2)

Maximum Swell Potential (%)

(Note 3)

Minimum Unconfined Compressive Strength

(psi)(Note 4)

Lime 12.0 1.0 160

FlyAsh N/A 1.0 160

CementKilnDust N/A 1.0 160

PortlandCement N/A 1.0 160

Lime-FlyAsh 12.3 1.0 160


Notes:

1. Whenlimeisused,thepHshouldbenolessthan12.0asmeasuredaftercompletionofinitialmixingwithstabilizingagentandatambienttemperature.

2. TestingofpHistobedoneinaccordancewithEades-GrimpHtestmethod(ASTMD6276).

3. SwellPotentialtobelessthan1.0percentat200psf,ASTMD4546.

4. Minimumof160psi(Mr>34,800psi,whereMr=10,000+124qU)infive(5)daysofmoistcuringat100oF(38oC)orambient(72°F)forseven(7)days.TestingisinaccordancewithASTMD1633MethodAforpozzolanicagentsandASTMD5102ProcedureBforHydratedLime.

Whenlimeisused,PlasticityIndexistobereportedfrominitialtofinalconstructiontoallinterestedpartiesandshallnotbeusedforacceptancepurposes.Thedesignstabilizingagentpercentageasdeterminedbythedesignershallbeincreasedby1.0percentinthefieldtoaccountforwaste,inertmaterials,andconstructionvariability.

5. Processing Materials - Itistheprimaryrequirementofthisspecificationtosecureacompletedsubgradestructuralsectioncontainingauniformstabilizedmixture.Themixtureistohaveauniformdensityandmoisturecontent,freefromlooseorsegregatedareas,wellboundforitsfulldepth,wellcured,andwithasurfacesuitableforplacingsubsequentcourses.Itshallbetheresponsibilityofthecontractortoregulatethesequenceoftheirwork,tousetheproperamountofstabilizingagent,maintainthework,andreworkthecourses,asnecessary,tomeettherequirements.

a. Application-Thesubgradeshallnotbetreatedwhentheambientairtemperaturefallsbelow40°,orwhenthesubgradematerialisfrozen,orwhenweatherpredictionssuggestthatsubgradematerialtemperaturemayfallbelowfreezingwithin24hours,unlesspriorwrittenapprovalofCityEngineeringhasbeenissued.Priortobeginninganytreatment,thesubgradeshallalsobeconstructedandfinishedtoasmoothanduniformsurfacethatisinconformitytothegradeandtypicalsectionspecified.Variationfromthesubgradeplanelevationspecifiedshallnotbemorethan±0.08ft.Thein-placedensityshallbeatleast95%ofmaximumdrydensityasdeterminedbyASTMD698,StandardProctorDensity,andwithin0to3%ofoptimummoisturecontentforflyashorcementtreatedsoils.Forlimetreatedmaterials,themoisturecontentshallbeatleast3%aboveoptimum.Stabilizingagentshallbeappliedattheminimumratespecifiedbythemixdesignforthedepthofstabilizedsubgradeshownontheplans.Therateshallbedeterminedfromadesignusingtheon-sitesoilsandshallmeettherequirementsfoundinSection4.2.2.Rateofapplicationshallbeverifiedusingarea/quantitycalculationsortestingofstabilizedsubgrade.Stabilizingagentshallbespreadonlyonthatareawherethefirstmixingoperationscanbecompletedduringthesameworkingday.Limeslurryshallnotbeleftexposedtotheairformorethanfourhourswithoutinitialmixing.CityEngineeringreservestherighttorequirevariationoftherateofapplicationofstabilizingagentfromthemixdesignapplicationratesduringtheprogressofconstructionasnecessarytomaintainthedesiredcharacteristicsofthestabilizedsubgrade.

Stabilizingagentshallbeappliedusingthefollowingmethods:


1. SlurryPlacement-Thedistributionofstabilizingagentshallbeattainedbysuccessiveapplicationsoverameasuredsectionofsubgradeuntiltheproperamountofagenthasbeenspread.Theamountspreadshallbetheamountrequiredformixingtothespecifieddepth,whichwillresultinthepercentagedeterminedinthedesign.Whenquicklimeisusedinplaceofhydratedlimetheamountofquicklimeusedwillbedeterminedbythecertifiedlimepurityforeachloadsuppliedasfollows:

Quicklime delivered X % purity * 1.32 = A

Quicklime delivered *X % inert material = B

A + B = total hydrated lime available

Note:Whenadoubletreatmentoflimeisrequired,thefirst50percentoftheagentshallbeplaced,moisturetreatedandallowedtomelloworcureforuptothreeweeks,asdeterminedbytheDesignEngineer.Thelasthalfofthelimeshallthenbeapplied.

2. DryPlacement(ThismethodcanonlybeusedforFlyAsh,cementkilndust,andPortlandcement)-Theamountofstabilizingagentspreadshallbetheamountrequiredformixingtothespecifieddepth,whichwillresultinthepercentagespecifiedbythedesign.Thestabilizingagentshallbedistributedinsuchamannerthatscatteringbywindwillbeminimal.Agentsshallnotbeappliedwhenwindconditions,intheopinionofCityEngineering’sinspector,aredetrimentaltoaproperapplication.Theblendedmaterialshallbesprinkledorwatereduntilmoisturecontentisasspecifiedinsubgradestabilizationdesign.Thecombinationofstabilizingagent,soilandwatershallbecalledthe“mixture.”Afterspreadingofstabilizingagentandduringmixing,watershallbeaddedtohydratetheagentandfordustcontrol.

b. HighSulfateTreatment-Wheresulfatesareover0.2percentthedesignermustaddressthemethodoftreatment.

c. Mixing-Nostabilizationshalltakeplacewhenprecipitationmaycausedamagetothesubgrade.Mixingshallbecontinuous.Thefulldepthofthetreatedsubgradematerialshallbemixedwithanapprovedmixingmachinetothespecifieddepthbelowthebottomofthepavementstructureand/orcurb.Themixingmachineshallmakeasufficientnumberofpassestoadequatelyachieve100percentofthematerialpassingtheone-inchsieveand60percentpassingthe1/4-inchsieve.Watershallbeaddedtothesubgradeduringmixingtoprovideamoisturecontentofatleast3percentabovetheoptimummoistureofthemixtureorasspecifiedinsubgradestabilizationdesign.Mixingandremixingwillbeperformed,asnecessary,toassistthestabilizingagent-soilreactionandproduceahomogeneousmixture.Mixingandremixingshallcontinueuntilthecombinationofstabilizingagentandsubgradematerialisfreeofstreaksorpocketsofstabilizingagent.


d. Mellowing(LimeorLime/FlyAshOnly)-Themoisturecontentofthesubgrademixtureshallbemaintainedaboveoptimumforaminimumof2daysanduntilthesubgradestabilizationdesigncriteriaismet.Remixingwillbedoneasnecessarytoassistthereaction,asdeterminedbythedesignengineer.Applicationofwatershallbeperformedasnecessaryduringthemellowingperiod;thematerialshallmaintainamoisturecontentofatleast3percentaboveoptimum.Thestabilizedmaterialshallnotbesubjectedtotraffic.Ifduringthemellowingperiodthematerialisnotinasemi-loosestate,thechemicalreactionprocessmayslowand,therefore,requireadditionaltimeand/ormixingasdeterminedbythedesignengineer.

e. FinalMixing(LimeorLime/FlyAshOnly)-Finalmixingofthetreatedsubgradeshallnotoccurifthetemperatureofthesoiltobestabilizedisbelow40°F.Thetreatedsubgradeshallbemaintainedatatemperatureof40°Foraboveuntilthetreatedmaterialhasbeencompacted.Thematerialshallbeuniformlymixedbyanapprovedmethodtomeetthefollowingrequirementswhentesteddrybylaboratorysieves:

Sieve Size Minimum Percent Passing

1-inchsieve 100

No.4sieve 60

6. Compaction -Compactionofthemixture,forthefulldepthofthestabilizedsubgradeshownontheplans,shallbeginassoonaspracticalafterfinalmixing.Stabilizedsubgradewithcementitiousstabilizationagentshallbecompletedwithin90minutesofthetimethecementitiousstabilizationagentandwateraremixed.Thefielddensityofthecompactedmixtureshallbeatleast95percentofthemaximumdrydensityoflaboratoryspecimenspreparedfromsamplestakenfromthetreatedsubgradematerialimmediatelypriortocompacting.ThespecimensshallbecompactedandtestedinaccordancewithASTMD698orASTMD558,asspecifiedinthesubgradestabilizationmixdesign.Thein-placefielddensityshallbedeterminedinaccordancewithASTMD1556,ASTMD2167orASTMD2922.Themoisturecontentofthemixtureofshallbebetween0to3percentabovetheoptimummoisturecontent.TheoptimummoisturecontentshallbedeterminedinaccordancewithASTMD698orASTMD558,asspecifiedinsubgradestabilizationdesign.Initialcompactionshallbedonebymeansofasheepsfootorsegmentedwheelroller.Finalcompactionshallbebymeansofasmoothwheelorpneumatictiredroller.Areasinaccessibletoamechanicalrollershallbecompactedtotherequireddensitybyothermeansacceptabletothedesignengineer.Allirregularities,depressions,orweakspotswhichdevelopshallbecorrectedimmediatelybyscarifyingtheareasaffected,addingorremovingmaterialsasrequired,andreshapingandre-compactingbymoistureconditioningandrolling.Addingadditionalstabilizedmaterialtoaninitialcuredsection,resultinginlaminationandpotentialslipplane,isnotallowed.Thesurfaceofthecourseshallbemaintainedinasmoothcondition,freefrom


undulationsandruts,untilotherworkisplacedthereonortheworkisaccepted.Shouldthematerial,duetoanyreasonorcause,losetherequiredstability,density,andfinishbeforethenextcourseorpavementisplaced,itshallbecorrectedandrefinishedatthesoleexpenseofthecontractor,asdirectedbyCityEngineering.

7. Finishing and Curing - Afterthefinallayerofstabilizedsubgradehasbeencompacted,theshapeofthesurfaceshallbeachievedbyblading.Thesurfaceshallbesmoothandconformtotherequiredlines,sections,andgrades,inaccordancewiththeplansandthoroughlycured,ortowithinaminimumof0.1footabovethefinishedsubgradeelevationtoallowfortrimmingtofinalgradepriortoplacementofsurfacecoarse.Thecompletedsectionshallthenbefinishedbyrollingwithsuitablepneumatictiredequipmentwithsufficientlylightefforttopreventhairlinecracking.Curingmaybeaccomplishedbyperiodicwaterapplicationtomaintainmoisturecontentpreventingsloughingorcrackingofthesurfaceofthestabilizedsubgradetoadepthnogreaterthan0.1foot,orbytheutilizationofabituminousseal.Whenbituminoussealisutilized,theminimumapplicationwillbeattherateof0.12gallonspersquareyard,asdirectedandapprovedbythedesignengineer.Thecompletedsectionshallbecuredforaminimumof5daysbeforefurthercoursesareaddedoranytrafficispermitted,unlessotherwisepermittedbythedesignengineer.Themoisturecuredurationmaybereducedifanon-yieldingsurfaceisobtainedtosupportconstructiontrafficandeitherthenextlayerofstabilizedsoilsareplacedorthepavementlayerisconstructed,asapprovedbytheEngineer.Ifthesurfaceofthefinishedlayerisabovetheapprovedplanelevationtolerancespecifiedinthissection,theexcessmaterialshallbetrimmed,removed,anddisposedof.Anylowareaswillbereplacedwiththesubsequentsurfacecourses.Noloosematerialshallbeleftinplaceaftertrimming.Aftertrimmingthestabilizedsubgradesurfaceshallberolledagainwithasteelwheelorpneumatictiredrollertosealthesurface.

8. Tolerances

a. Thickness-Stabilizedzonethicknessshallbeverifiedbytheuseofphenolphthaleinandshallbeperformedatintervalsofapproximately500feetineachlane.Whenthemeasurementofthethicknessisdeficientbymorethan1inchfromtheplanthickness,twoadditionallocationsshallbemeasuredrandomlywithinthedeficientareaandusedindeterminingtheaveragethickness.Whentheaveragethicknessisdeficientbymorethan1inch,theentireareashallbereprocessedtomeetthedesignparametersortheroadwaydesignsectionmustbere-evaluated.

b. Grade-Priortoplacementofsurfacecourse,anydeviationinexcessof1/2inchincross-sectionand1/2inchin10feetmeasuredlongitudinallyshallbecorrected.Variationsinexcessofthistoleranceshallbecorrectedbythecontractor,atthecontractor’sexpense,inamannersatisfactorytoCityEngineering.Thicknessrequirementsshallbemetinareascorrectedforgrade.


c. Strength-Thestabilizedsubgrademustdevelopalaboratorycompressivestrengthofatleast160psiat5daysinaccordancewithTable6.5.4.Samplesshallbemoldedfromstabilizedsoilwithin1.5hoursoffinalmixingwiththematerialcompactedperASTMD558orASTMD698,asspecifiedinsubgradestabilizationdesign,atthefieldmoisturecontent.

9. Conformity with Plans and Specifications - Whenthicknessand/orstrengthcriteriafailtomeetdesignparameters,evenafterallpossibleattemptshavebeenmadetocorrectsaiddeviations,remediationwillberequiredaslistedinTable13.EvaluationoftheroadwaypavementsectionwillbemadebytheDesignEngineerwithwrittenapprovalofCityEngineering.Thepavementstructuralsectionshallbeadjustedtocompensateforanydeficiencyinthestabilizedsubgradethicknessandstrength,atthecontractor’sexpense.PlacementofsubsequentsurfacecoursewillnotoccuruntilthestabilizedsubgradehasbeenacceptedinwritingbyCityEngineering.

Table 13 Conformity Specifications

Deficiency Remediation

Lessthan25%ofdesignthickness Evaluateroadwaydesignsection

Greaterthan25%ofdesignthickness Removeandreplace

Lessthan25%ofrequiredstrength Evaluateroadwaydesignsection

Greaterthan25%ofrequiredstrength Removeandreplace

10. Measurement - Theareaofstabilizedsubgradeshallbemeasuredbytheplanquantitiescompleted,inplace,andaccepted.Noseparatemeasurementofdepthorarea,exceptasrequiredforthicknesstestingshallbeperformed.Thequantityofstabilizingagentacceptedandusedshallbemeasuredbythetonofflyash,Portlandcement,cementkilndust,orhydratedlimeused(orthecalculateddryhydratedlimecontentofthelimeslurry).

11. Testing and Inspection - TestingandinspectionshallbeperformedinaccordancewithTable14.


Table 14 Schedule for Minimum Materials Sampling and Testing (Chemically Stabilized Soils)

Test Type Test Standard Minimum Frequency of Tests

Sampling AASHTOT87Oneper2,500squareyards

SamplePreparation ASTMD3551

MaximumDryDensityandOptimumMoistureContent

ASTMD698(Lime)ASTMD558(Cement)

MinimumofonepersoiltypeorasdirectedbyCityEngineering

InPlaceSoilDensity ASTMD1556ASTMD2167ASTMD6938 Onetestforeach250lanefeet

(notlessthanonetestperday)InPlaceMoistureContent ASTMD2216ASTMD6938

Ph ASTMD6276 Onetestper2,500squareyards

Swell ASTMD4546MethodB

Minimumonetestper2,500squareyardsorasdirectedbyCityofColoradoSprings,

UnconfinedCompressiveStrength(Lime) ASTMD5102(ProcedureB) Onesetoffourcylindersper

2,500squareyards.

CompressiveStrengthCementitiousAgents ASTMD1633(MethodA) Onesetoffourcylindersper

2,500squareyards.

AtterbergLimits AASHTOT89&T90 Onetestper2,500squareyards

StabilizationThickness Asdirectedbytestingagency Onetestevery500feetperlane

6.6 Mechanically Stabilized Subgrade

Thisworkincludesmechanicallystabilizedsubgradeofbase/subbasecourseand/orsubgradeimprovementintheconstructionofpavedorunpavedroadways.Designdetailsforgeogridreinforcement,suchasgeogridtype,fillthickness,pavementcross-sectionandassociateddetails,shallbeasshownontheprojectdrawings.Purpose-Thepurposeoftheworkshallbetoprovideastabilizedpavingplatformsectiononwhichpavingmaterialscanbeplaced.Subgradestabilizationshallextendtothebackofcurbasaminimum.Thisitemshallnotbeusedtoretainmoistureinsubgradesunlessretainingmoistureinthesectioncanbeassured.Thisspecificationshallbeusedforaconstructionplatformandnotasameansofmitigatingswell.

1. Materials

a. Definitions

1. Mechanically Reinforced-Placementofageogridimmediatelyoverasoftsubgradesoilinordertoimprovethebearingcapacityandmitigatedeformationofthesubgradesoil.Thegoalofthisapplicationmaybetoreducedeeperexcavationrequirements,improveconstructionefficiency,reducetheamountofaggregatesubbase/basematerialrequired,provideastiffworkingplatformforpavementconstruction,orcombinationofthese.


2. Geogrid -Abiaxialpolymericgridformedbyaregularnetworkofintegrallyconnectedtensileelementswithaperturesofsufficientsizetoallowinterlockingwithsurroundingsoil,rock,orearthtofunctionprimarilyasreinforcement.

3. Multi-Layer Geogrid -Ageogridproductconsistingofmultiplelayersofgridwhicharenotintegrallyconnectedthroughout.

4. Extruded Geogrid–Ageogridproductformedbyextrusionofapolypropyleneorpolypropylene/polyethylenecopolymersheetfollowedbyitsperforationwithaprecisearrangementofholesandsubsequentstretching,ordrawing,intothefinishedproduct.

5. Woven Geogrid–Ageogridproductformedbyweavingdiscretestripsofpolymerintoanetwork.Thesegeogridsusuallyrequireaprotectivecoatingtoprotectthepolymerfrompre-maturedegradation.

6. Minimum Average Roll Value (MARV)-ValuebasedontestinganddeterminedinaccordancewithASTMD4759-92.

7. True Initial Modulus in Use-Theratiooftensilestrengthtocorrespondingzerostrain.ThetensilestrengthismeasuredviaASTMD6637atastrainrateof10percentperminute.ValuesshownareMARVs.Formulti-layergeogridproducts,ribtensiletestingshallbeperformedonthemulti-layerconfigurations,asprescribedbyASTMD6637

8. Junction Strength-BreakingtensilestrengthofjunctionswhentestedinaccordancewithGRI-GG2asmodifiedbyAASHTOStandardSpecificationforHighwayBridges,1997Interim,usingasingleribhavingthegreaterof3junctionsoraminimum8inchmachinedirectionsampleandtestedatastrainrateof10percentperminutebasedonthisgaugelength,valuesshownareMARVs.Formulti-layergeogridproducts,junctionstrengthtestingshallbeperformedacrossjunctionsfromeachlayerofgridindividually,andresultsshallnotbeassumedasadditivefromsinglelayerstomultiplelayers.

9. Flexural Stiffness(alsoknownasFlexuralRigidity)-ResistancetobendingforcemeasuredviaASTMD1388-96,OptionA,usingspecimendimensionsof864millimetersinlengthby1apertureinwidth,valuesshownareMARVs.Formulti-layergeogridproducts,flexuralstiffnesstestingshallbeperformeddirectlyonthemulti-layerconfigurationwithoutusinganyconnectingelementsotherthanthoseusedcontinuouslythroughouttheactualproduct,andresultsshallnotbeassumedasadditivefromtestingperformedonasinglelayerofthemulti-layerproduct.

10. Aperture Stability Modulus(alsoknownasTorsionalRigidityorTorsionalStiffness)-Resistancetoin-planerotationalmovementmeasuredbyapplyinga20kg-cm(2.0m-N)momenttothecentraljunctionofa9-inchby9-inchspecimenrestrainedatitsperimeter,valuesshownareMARVs.Formulti-layergeogridproducts,torsionalstiffnesstestingshallbeperformedoneachlayerofgridindividually,andresultsshallnotbeassumedasadditivefromsinglelayerstomultiplelayers.


11. Granular Fill Material –Thepreferredgradationforbasereinforcementapplicationiswell-gradedcrushedaggregatefillwithamaximumparticlesize(100percentpassing)of1½inches,andlessthan10%fines(passingthe#200sieve).RecycledconcretemaybeusedonlywithpolypropylenegeogridsinaccordancewithFederalHighwayAdministration(FHWA)2001.

2. Manufacturers

a. AllmanufacturerswillbeconsideredprovidedtheymeetthesubmittalprocessasperTable6.6.3.

3. Geogrid Material Properties

a. StructuralSoilReinforcementGeogrid–ThegeogridshallbeintegrallyformedanddeployedasasinglelayerhavingthefollowingcharacteristicsaccordingtoTable15(allvaluesareminimumaveragerollvaluesunlessarangeorcharacteristicisindicated.)

b. Geotextilematerialsshallnotbeconsideredasanalternatetogeogridmaterialsforsubgradeimprovementorbase/sub-basereinforcementapplications.Ageotextilemaybeusedinthecross-sectiontoprovideseparation,filtrationordrainage;however,nostructuralcontributionshallbeattributedtothegeotextile.

Table 15 Geogrid Structural Properties

Property Test Method Units Type 1 Type 2

ApertureStabilityModulusat20cm-kg(2.0m-N) Kinney(2001) m-N/deg 0.32 0.65

RibShape Observation N/A RectangularorSquare

RectangularorSquare

RibThickness Calipered In 0.03 0.05

NominalApertureSize I.D.Calipered In 1.0to1.5 1.0to1.5

JunctionStrength GRI-GG2-20001 ratio Note1 Note1

FlexuralRigidity ASTMD1388-96Note2 Mg-cm 250,000 750,000

MinimumTensileStrength@2%Strain:

ASTMD6637-01Note4-MD3 Lb/ft 280 410

-CMD3 Lb/ft 450 620

MinimumTensileStrength@5%Strain:

ASTMD6637-01Note4-MD3 Lb/ft 580 810

-CMD3 Lb/ft 920 1,340


NOTES:

1. TheratioofJunctionStrength/UltimateTensileStrengthmustmeetorexceed75%.

2. ResistancetobendingforcemeasuredviaASTMD-5732-95,usingspecimensofwidthtworibswide,withtransverseribscutflushwithexterioredgesoflongitudinalribs(asa“ladder”),andoflengthsufficientlylongtoenablemeasurementoftheoverhangdimension.

3. MD=machinedirection(alongrolllength);CMD=cross-machinedirection(acrossrollwidth).

4. TrueresistancetoelongationwheninitiallysubjectedtoaloaddeterminedinaccordancewithASTMD6637withoutdeformingtestmaterialsunderloadbeforemeasuringsuchresistanceoremploying“secant”or“offset”tangentmethodsofmeasurementsoastooverstatetensileproperties.

4. Construction Platform Design

ConstructionplatformdesignshallbeperformedundersupervisionofandsignedbyaProfessionalEngineerregisteredintheStateofColoradopracticingasageotechnicalengineer.TherecommendedprocedureshallbefollowedasoutlinedinAASHTOPP46-01.Appropriatepartialsafetyfactorsshallbeappliedtoresultsobtainedusinggeogridshavingpropertiesorcharacteristicsoutsidetherangeofrigorousmodelvalidation(GiroudandHan,2004).ThismethodhasbeenendorsedbynumerousDepartmentofTransportationsandGovernmentAgenciessuchastheFederalHighwayAdministrationandArmyCorpsofEngineers.Apipingratioanalysis(D15fill/D85subgrade)shallbeperformedtodeterminetheneedofaseparationfabric.Ifthepipingratioislessthan5thennoseparationfabricisrequired.Ifthepipingratioisgreaterthan5thenaseparationfabricisrequiredbelowthegeogrid.FinaldeterminationofconstructionplatformshallbeapprovedbyCityEngineering.

5. Utility Cuts

Repairofutilitycutsingeogridmaterialshallbeaccomplishedpermanufacturerspecifications.

6.7 Proof Rolling

TheSubgradeplatformshallbethoroughlyproof-rolledtothesatisfactionoftheCityInspectorpriortoplacementofbasecourse(orpaving)andthebasecourseshallbethoroughlyproof-rolledtothesatisfactionoftheCityinspectorpriortopaving.ReferenceSection205oftheCity’sStandardSpecifications.

6.8 Water Testing

Assoonaspracticaluponfinalpavementconstructionthefinishedpavementsurfaceshallbewater-testedtothesatisfactionoftheCityEngineeringinspectortoconfirmpositivesurfacedrainageinalldirectionspriortoacceptanceofthestreet.Watershallbeappliedusingawatertruckspraybarorsimilardeviceatarateadequatetodemonstratepositivedrainageflowacrossthecrownandintothestreetgutters.

.


7.0 Definitions

AASHTO:AmericanAssociationofStateHighwayandTransportationOfficials

Adhesive Failure:Lossofbondbetweenthejointsealantandthejoint,orbetweentheaggregateandthebinder.

Agency:Thejurisdictionorowneroftheprojectanditsrepresentatives.

Aggregate Base (base course):Crushedstoneorgravel,immediatelyunderthesurfacecourse.

Aggregate Interlock:Interactionofaggregateparticlesacrosscracksandjointstotransferload.

Alligator Cracks:Interconnectedcracksformingaseriesofsmallblocksresemblinganalligator’sskinorchickenwire.

Analysis Period:Theperiodoftimeforwhichtheeconomicanalysisistobemade;ordinarilywillincludeatleastonerehabilitationactivity.

Asphalt Emulsion Slurry Seal:Amixtureofemulsifiedasphalt,fineaggregateandmineralfiller,withwateraddedtoproduceslurryconsistency.Sealsareusedasapreventativemaintenancetreatmenttoprovideanewwearingsurfaceandtofillsmallcracks.

Asphalt Leveling Course:Acourse(asphalt-aggregatemixture)ofvariablethicknessusedtoeliminateirregularitiesinthecontourofanexistingsurfacepriortosuperimposedtreatmentorconstruction.

Asphalt Overlay:Oneormorecoursesofasphaltconstructiononanexistingpavement.Theoverlaygenerallyincludesalevelingcourse,tocorrectthecontouroftheoldpavement,followedbyuniformcourseorcoursestoprovideneededthickness.

Asphalt Tack Coat:AlightapplicationofemulsifiedasphaltappliedtoanexistingasphaltorPortlandcementconcretepavementsurface.Itisusedtoensureabondbetweenthesurfacebeingpavedandtheoverlyingcourse.Typically0.10gals/yd2ofCSS1h.

ASTM:AmericanSocietyforTestingMaterials

Binder:AsphaltCementusedtoholdstonestogetherforpaving.

Binder Course:Thelayerofasphaltcementconcretepavementunderlyingthesurfacecourse.

Bituminous:Likeorfromasphalt.

Bleeding or Flushing:Theupwardmovementofasphaltinanasphaltpavementresultingintheformationofafilmonthepavementsurface.Itcreatesashiny,glass-like,reflectivesurfacethatmaybetackytothetouchinwarmweather.

Block Cracking:Theoccurrenceofcracksthatdividetheasphaltsurfaceintoapproximatelyrectangularpieces,typicallyonesquarefootormoreinsize.


California Bearing Ratio Test (CBR):Anempiricalmeasureofbearingcapacityusedforevaluatingbases,subbases,andsubgradesforpavementthicknessdesign.

Centerline:Thepaintedlineseparatingopposingtrafficlanes.

Channels:Aditchorcanaladjacenttheroadway.

Chipping:Breakingorcuttingoffsmallpiecesfromthesurface.

Chip Seal:Athinlayerofemulsifiedasphaltcementinwhichaggregateisembedded.Thesealisplacedtoimprovethetextureofthepavementsurfacetoincreaseskidresistanceanddecreasepermeabilityofthesurface.

City Street:Astreetwhosetrafficispredominantlylocalincharacter.

Cohesive Failure:Thelossofamaterial’sabilitytobondtoitselforitssubstrate.Resultsinthematerialsplittingortearingapartfromitselforitssubstrate(i.e.jointsealantsplitting).

Composite Pavement:Apavementstructurecomposedofanasphaltcementconcretepavementwearingsurfaceoveraggregatebasecourseortreatedsubgrade.

Contractor:Thelanddeveloperoritsagentsinvolvedintheconstructionoftheproject.

Corrugations (Washboarding):Aformofplasticmovementtypifiedbyripplesacrossthepavementsurface.Mostcommoninaggregatesurficialpavementsbutoccursinasphaltcementconcretepavementsaswell.

Crack:Approximatelyverticalrandomcleavageofthepavementduetothermalorloadaction.

Crack Seal:Anasphaltcementorsimilarmaterialappliedintoapavementcracktoprovideanon-permeableseal.Thesealantmusthaveadequatecharacteristicstoprovidebondingtoeachsideofthecrack.

CTS:ChemicallyTreatedSubgrade

Deflection:Theamountofdownwardverticalmovementofasurfaceduetotheapplicationofaloadtothesurface.

• Rebound Deflection:Theamountofverticalreboundofasurfacethatoccurswhenaloadisremovedfromthesurface.

• Representative Rebound Deflection:Themeanvalueofmeasuredrebounddeflectionsinatestsectionplustwostandarddeviations,adjustedfortemperatureandmostcriticalperiodoftheyearforpavementperformance.

• Residual Deflection:Thedifferencebetweenoriginalandfinalelevationsofasurfaceresultingfromtheapplicationto,andremovalofoneormoreloadsfrom,thesurface.

Design ESAL:Thetotalnumberofequivalent80kN(18,000lb)single-axleloadapplicationsexpectedduringtheDesignPeriod.

Design Lane:Thelaneonwhichthegreatestnumberofequivalent80kN(18,000lb)single-axleloadsisexpected.Normallythiswillbeeitherlaneofatwo-laneroadwayortheoutsidelaneofamulti-lanehighway.


Design Period:Thenumberofyearsfrominitialconstructionorrehabilitationuntilterminalservicelife.ThistermshouldnotbeconfusedwithpavementlifeorAnalysisPeriod.Byaddingasphaltoverlaysasrequired,pavementlifemaybeextendedindefinitely,oruntilgeometricconsiderationsorotherfactorsmakethepavementobsolete.

Disintegration:Thebreakingupofapavementintosmall,loosefragmentsduetotrafficorweathering.

Distortion:Anychangeofapavementsurfacefromitsoriginalshape.

Drainage Coefficients:Factorsusedtomodifylayercoefficientsinflexiblepavementsorstressesinrigidpavementsasafunctionofhowwellthepavementstructurecanhandletheadverseeffectofwaterinfiltration.

Edge Cracking:Fractureandmaterialslossinpavementswithoutpavedshoulderswhichoccuralongthepavementperimeter.Causedbysoilmovementbeneaththepavement.

Effective Thickness:ThethicknessthatapavementwouldbeifitcouldbeconvertedtoFull-Depthasphaltcementconcretepavement.

Embankment (Embankment Soil):Thepreparedornaturalsoilunderlyingthepavementstructure.

Embrittlement:Premature(surficial)crackingofanasphaltconcretepavementduetooxidativeagingoftheasphaltcement.

End Result Specifications:Specificationsthatrequirethecontractortotaketheentireresponsibilityforsupplyingaproductoranitemofconstruction.Thehighwayagency’sresponsibilityistoeitheracceptorrejectthefinalproductorapplyapriceadjustmentthatcompensatesforthedegreeofcompliancewiththespecifications.(Endresultspecificationshavetheadvantageofaffordingthecontractorflexibilityinexercisingoptionsforusingnewmaterials,techniques,andprocedurestoimprovethequalityand/oreconomyoftheendproduct.)

ESAL:EquivalentSingleAxelLoad

ESAL to Failure:Thenumberofdesign18kip(18,000pound)axleloadcyclesrequiredtoproduceapproximately40percentfatiguecrackingascalculatedusingAAMASequationsbasedonasphaltcementconcretepavementResilientModulusandtensilestrainatthebottomoftheACCPlayer.

Equivalent 80kN (18,000 lb) Single-Axle Load (ESAL):Theeffectonpavementperformanceofanycombinationofaxleloadsofvaryingmagnitudeequatedtothenumberof80kN(18,000lb)single-axleloadsrequiredtoproduceanequivalenteffect.

Fatigue Cracking:Aseriesofsmall,jagged,interconnectingcrackscausedbyfailureoftheasphaltcementconcretepavementsurfaceunderrepeatedtrafficloading(alsocalledalligatorcracking.)

Fault:Differenceinelevationbetweenopposingsidesofajointorcrack.


Flexible Pavement:Pavementstructuresgenerallyconsistingofasphaltcementconcretepavementsurfacingthatmaintainsintimatecontactwithanddistributesloadstothesubbaseorsubgradeanddependsuponaggregateinterlock,particlefriction,andcohesionforstability.

Flowable Backfill:Abackfillmaterialcomposedofalow-strength,self-levelingconcretematerial,composedofvariouscombinationsofcementflyash,aggregate,waterandchemicaladmixturesusedto“flow”intoareasrequiringbackfillthatwillprovidedensityandstrengthwithoutcompaction.

Fog Seal:Athinlayerofemulsifiedasphaltcementappliedtothepavementsurface.Thesealisplacedasapreventivetreatmenttorejuvenatetheasphaltconcretepavementbyimprovingflexibilityandtodecreasethepermeabilityofthesurface.

Free Edge:Pavementborderthatisabletomovefreely.

Full-Depth Asphalt Pavement:ThetermFULL-DEPTH(registeredbytheAsphaltInstitutewiththeU.S.PatentOffice)certifiesthatthepavementisoneinwhichasphaltmixturesareemployedforallcoursesabovethesubgradeorimprovedsubgrade.AFull-Depthasphaltpavementislaiddirectlyonthepreparedsubgrade.

Functional Classification:Amethodofseparatingandclassifyingstreetsaccordingtotheirpurposeorfunctioninthenetworkofstreets,i.e.residentialcollectors,commercialcollectors,residentiallocals.

Grade Depressions:Localizedlowareasoflimitedsizewhichmayormaynotbeaccompaniedbycracking.

Hairline Crack:Afracturethatisverynarrowinwidth,lessthan3mm(0.12in.).

Heavy Trucks:Twoaxle,six-tiretrucksorlarger.Pickup,panelandlightfour-tiretrucksarenotincluded.Truckswithheavy-duty,widebasetiresareincluded.

Hot Bituminous Pavement:SeeHotMixAsphalt

Hydroplaning:Thedangerousactionofavehiclebeingdrivenonapavementoverwhichafilmofrainorotherwaterhasformed;onreachingacertainspeed,thevehicle’stirestendtorideuponthewatersurfaceratherthanthepavement,drasticallyreducingthedriver’scontrolofthevehicle.

Hot Mix Asphalt:High-quality,thoroughly-controlledhotmixtureofasphaltcementandwell-graded,highqualityaggregate,thoroughlycompactedintoauniformdensemass.

Incentive/Disincentive Provision (for quality):Apayadjustmentschedulewhichfunctionstomotivatethecontractortoprovideahighlevelofquality.(Apayadjustmentschedule,evenonewhichprovidesforpayincreases,isnotnecessarilyanincentive/disincentiveprovision,asindividualpayincreases/decreasesmaynotbeofsufficientmagnitudetomotivatethecontractortowardhighquality).

Instability:Thelackofresistancetoforcestendingtocausemovementordistortionofapavementstructure.

Internal Vibration:Vibrationbymeansofvibratingunitslocatedwithinthespecifiedthicknessofpavementsectionandaminimumdistanceaheadofthescreedequaltothepavementthickness.


Lane Line:Boundarybetweentravellanes,usuallyapaintedstripe.

Lane-to-Shoulder Drop-off:Thedifferenceinelevationbetweenthetrafficlaneandshoulder.

Lane-to-Shoulder Separation:Wideningofthejointbetweenthetrafficlaneandtheshoulder.

Layer Coefficient:Theempiricalrelationshipbetweenstructuralnumber(SN)andlayerthicknesswhichexpressestherelativeabilityofamaterialtofunctionasastructuralcomponentofthepavement.

Lime Stabilized Subgrade:Apreparedandmechanicallycompactedmixtureorlime,waterandsoilbelowthepavementsystem.

Lime-Fly Ash Base:Ablendofmineralaggregate,lime,flyashandwater,combinedinproperproportionswhich,whencompacted,producesadensemass.

Lime-Fly Ash Stabilized Subgrade:Apreparedandmechanicallycompactedmixtureoflime,flyash,waterandsoilbelowthepavementsystem.

Load Equivalency Factor (LF):Afactorusedtoconvertapplicationsofaxleloadsofanymagnitudetoanequivalentnumberof80kN(18,000lb)singleaxleloads.

Longitudinal:Paralleltothecenterlineofthepavement.

Longitudinal Crack:Acrackthatfollowsacourseapproximatelyparalleltothecenterline.

Maintenance:Thepreservationoftheentireroadway,includingsurface,shoulders,roadsides,structures,andsuchtrafficcontroldevicesasarenecessaryforitssafeandefficientutilization.

Materials/Methods Specifications:Specificationsthatdirectthecontractortousespecifiedmaterialsindefiniteproportionsandspecifictypesofequipmentandmethodstoplacethematerial.

Method Specifications:SeeMaterials/MethodsSpecifications.

Moisture Stabilized Subgrade:Swellingsoilswhichhavebeenstabilizedtolowornilswellbyadditionofmoisture.

Moisture Treatment:Additionofmoistureat1to3percentabovestandardProctoroptimummoisturecontentandcompactionto95percentdensity.

Parametric Analysis:Astudyofasetofphysicalpropertieswhosevaluesdeterminethecharacteristicsorbehaviorofsomething;usedtoisolatethesignificanceofindividualvariables.

Patch:Anareawheretheexistingpavementhasbeenremovedandreplacedwithanewmaterial.

Patch Deterioration:Distressoccurringwithinapreviouslyrepairedarea.

Pavement Structure (Pavement):Acombinationofsubbase,basecourse,andsurfacecourseplacedonasubgradetosupportthetrafficloadanddistributeittotheroadbed.


Pavement Condition Indicator (PCI):Ameasureoftheconditionofanexistingpavementsectionataparticularpointintime,suchascrackingmeasuredinfeetpermile,orfaultingmeasuredininchesofwheelpathfaultingpermile.Whenconsideredcollectively,pavementconditionindicatorsprovideanestimateoftheoveralladequacyofaparticularroadway.

Pavement Design (Design, Structure Design):Thespecificationsformaterialsandthicknessesofthepavementcomponents.

Pavement Distress Indicator:SeePavementConditionIndicator.

Pavement, Flexible:Pavementstructuresgenerallyconsistingofasphaltcementconcretepavementsurfacingthatmaintainsintimatecontactwithanddistributesloadstothesubbaseorsubgradeanddependsuponaggregateinterlock,particlefriction,andcohesionforstability.

Pavement Performance:Thetrendofserviceabilitywithloadapplications.

Pavement Rehabilitation:Workundertakentoextendtheservicelifeofanexistingfacility.Thisincludesplacementofadditionalsurfacingmaterialand/orotherworknecessarytoreturnanexistingroadway,includingshoulders,toaconditionofstructuralorfunctionaladequacy.Thiscouldincludethecompleteremovalandreplacementofthepavementstructure.

Pavement, Rigid:ApavementstructureconsistingofPortlandcementconcretepavementsurfacing,withorwithoutsubbase.

Performance Period:SeeDesignPeriod.

Performance Specifications:Specificationsthatdescribehowthefinishedproductshouldperformovertime.Forhighways,performanceistypicallydescribedintermsofchangesinphysicalconditionofthesurfaceanditsresponsetoload,orintermsofthecumulativetrafficrequiredbringingthepavementtoaconditiondefinedas“failure”.Specificationscontainingwarranty/guaranteeclausesareaformofperformancespecifications.(Otherthanthewarranty/guaranteetype,performancespecificationshavenotbeenusedformajorhighwaypavementcomponents(subgrades,bases,ridingsurfaces)becausetherehavenotbeenappropriatenondestructiveteststomeasurelong-termperformanceimmediatelyafterconstruction.Theyhavebeenusedforsomeproducts(e.g.,highwaylighting,electricalcomponentsandjointsealantmaterials)forwhichtherearetestofperformancethatcanberapidlyconducted.)

Performance-Based Specifications:Specificationsthatdescribethedesiredlevelsoffundamentalengineeringproperties(e.g.,ResilientModulus,creepproperties,andfatigueproperties)thatarepredictorsofperformanceandappearinprimarypredictionrelationships(i.e.,modelsthatcanbeusedtopredictpavementstress,distress,orperformancefromcombinationsofpredictorsthatrepresenttraffic,environmentalroadbed,andstructuralconditions.)[Becausemostfundamentalengineeringpropertiesassociatedwithpavementsarecurrentlynotamenabletotimelyacceptancetesting,performance-basedspecificationshavenotfoundapplicationinhighwayconstruction].

Performance-Related Specifications:Specificationsthatdescribethedesiredlevelsofkeymaterialsandconstructionqualitycharacteristicsthathavebeenfoundtocorrelatewithfundamentalengineeringpropertiesthatpredictperformance.Thesecharacteristics(forexample,airvoidsinasphalticpavements,andstrengthofconcretecores)are


amenabletoacceptancetestingatthetimeofconstruction.Trueperformance-relatedspecificationsnotonlydescribethedesiredlevelsofthesequalitycharacteristics,butalsoemploythequantifiedrelationshipscontainingthecharacteristicstopredictsubsequentpavementperformance.Theythusprovidethebasisforrationalacceptanceand/orpriceadjustmentdecisions.

Planned Stage Construction:Theconstructionofroadsandstreetsbyapplyingsuccessivelayersofasphaltcementconcretepavementaccordingtodesignandapredeterminedtimeschedule.

Plant-Mix Base:Afoundationcourse,producedinanasphaltmixingplant,whichconsistsofamineralaggregateuniformlycoatedwithasphaltcementoremulsifiedasphalt.

Portland Cement Concrete Pavement (PCCP):Highquality,thoroughlycontrolledmixtureofPortlandcement,water,andwell-graded,highqualityaggregate,thoroughlymixedandplacedasauniformdensemass.

Pothole:Abowl-shapeddepressionofvaryingsizesinthepavementsurface,resultingfromlocalizeddisintegration.

Prepared Roadbed:In-placeroadbedsoilscompactedorstabilizedaccordingtoprovisionsofapplicablespecifications.

Prescriptive Specifications:SeeMaterials/MethodsSpecifications.

Present Serviceability:Theabilityofaspecificsectionofpavementtoserve,fortheuseintended,mixedtrafficonthedayofrating.

Present Serviceability Index (PSI):Amathematicalcombinationofvalues,obtainedfromcertainphysicalmeasurementsofalargenumberofpavements,soformulatedastopredict,withinprescribedlimits,thePresentServiceabilityRating(PSR)forthosepavements.

Present Serviceability Rating (PSR):Themeanoftheindividualratingsmadebythemembersofaspecificpanelselectedforthepurpose.

Proof Roll:Atestmethodforsubgradesoilsinwhichaloadedtruck(18,000poundaxleweight)isdrivenoverthesubjectareatodelineatesoftoryieldingareas.

QA/QC Specifications:SeeQualityAssuranceSpecifications.

QC/QA Specifications:SeeQualityAssuranceSpecifications.

Quality Assurance:Allthoseplannedandsystematicactionsnecessarytoprovideconfidencethataproductorfacilitywillperformsatisfactorilyinservice.Qualityassuranceaddressestheoverallproblemofobtainingthequalityofservice,product,orfacilityinthemostefficient,economical,andsatisfactorymannerpossible.Withinthisbroadcontext,qualityassuranceinvolvescontinuedevaluationoftheactivitiesofplanning,design,developmentofplansandspecifications,advertisingandawardingofcontracts,construction,andmaintenance,andtheinteractionsoftheseactivities.

Quality Assurance Specifications:Acombinationofendresultspecificationsandmaterialsandmethodsspecifications.Thecontractorisresponsibleforqualitycontrol(processcontrol),andtheAgencyisresponsibleforacceptanceoftheproduct.(Quality


assurancespecificationstypicallyarestatisticallybasedspecificationsthatusemethodssuchasrandomsamplingandlot-by-lottesting,whichletthecontractorknowifhisoperationsareproducinganacceptableproduct.)

Quality Control:Thosequalityassuranceactionsandconsiderationsnecessarytoassessproductionandconstructionprocessessoastocontrolthelevelofqualitybeingproducedintheendproduct.Thisconceptofqualitycontrolincludessamplingandtestingtomonitortheprocessbutusuallydoesnotincludeacceptancesamplingandtesting.

Raveling:Thewearingawayofthepavementsurfacecausedbythedislodgingofaggregateparticles.

Recipe Specifications:SeeMaterials/MethodsSpecifications.

Reflection Cracking:Cracksinasphaltoverlaysthatreflectthecrackpatterninthepavementstructureunderneath.

Resilient Modulus Test:Ameasureofthemodulusofelasticityofroadbedsoilorotherpavementmaterial.

Resistance Value (R-value):Atestforevaluatingbases,subbases,andsubgradesforpavementthicknessdesign.

Roadbed:Thegradedportionofahighwaybetweentopandsideslopes,preparedasafoundationforthepavementstructureandshoulder.

Roadbed Material:Thematerialbelowthesubgradeincutsandembankmentsandinembankmentfoundations,extendingtosuchdepthasaffectsthesupportofthepavementstructure.

Roadway:Allfacilitiesonwhichmotorvehiclesareintendedtotravelsuchassecondaryroads,interstatehighways,streetsandparkinglots.

Roadway Land Use:Aclassificationbasedontheuseoflandadjacentorservicedbythestreet.Theclassificationisusedtoseparatestreetsfordifferentvolumeassumptions.

Roughometer:Asingle-wheeledtrailerinstrumentedtomeasuretheroughnessofapavementsurfaceinaccumulatedmillimeters(inches)permile.

Rubberized Asphalt Cement:Blendofasphaltcementandpre-vulcanizedrubber.

Rutting:Longitudinalsurfacedepressionsinthewheelpaths.

Selected Material:Asuitablenativematerialobtainedfromaspecifiedsourcesuchasaparticularroadwaycutorborrowarea,ofasuitablematerialhavingspecifiedcharacteristicstobeusedforaspecificpurpose.

Serviceability:Theabilityattimeofobservationofapavementtoservetraffic(autosandtrucks)whichusethefacility.

Shoving:Permanent,longitudinaldisplacementofalocalizedareaofthepavementsurfacecausedbytrafficpushingagainstthepavement.

Single Axle Load:Thetotalloadtransmittedbyallwheelsofasingleaxleextendingthefullwidthofthevehicle.


Skid Hazard:Anyconditionthatmightcontributetomakingapavementslipperywhenwet.

Slippage Cracks:Cracks,sometimescrescent-shaped,thatpointinthedirectionofthethrustofwheelsonthepavementsurface.

SMA (Stone Matrix Asphalt, Split-Mastic Asphalt):Anasphaltmixdesigncomposedoflargestonescreatingastonetostonematrix,oftencontaininglargepercentagesofasphaltcementandfillers.

Soil Cement Base:Ahardenedmaterialformedbycuringamechanicallycompactedintimatemixtureofpulverizedsoil,Portlandcementandwater,usedasalayerinapavementsystemtoreinforceandprotectthesubgradeorsubbase.

Stabilized Subgrade:Asubgradesoilthathasbeenalteredbyachemicalagenttomakesuitableforsubgradeconstructionandpavementsupport.

Standard Deviation:Theroot-mean-squareofthedeviationsaboutthearithmeticmeanofasetofvalues.

Statistically Based Specifications:Specificationsbasedonrandomsampling,andinwhichpropertiesofthedesiredproductorconstructionaredescribedbyappropriatestatisticalparameters.

Structural Number (SN):Anindexnumberderivedfromananalysisoftraffic,roadbedsoilconditions,andenvironmentwhichmaybeconvertedtothicknessofflexiblepavementlayersthroughtheuseofsuitablelayercoefficientsrelatedtothetypeofmaterialbeingusedineachlayerofthepavementstructure.

Subbase:Thelayerorlayersofspecifiedorselectedmaterialofdesignedthicknessplacedonasubgradetosupportabasecourse.

Subbase (Subbase Course):Thelayerofgradedsand-gravelorstabilizedsubgradematerialbetweenthesurfaceoftheembankmentsoilandthebasecourse(andsurfacingcoursewhenthereisnobasecourse).

Subgrade:Thesoilpreparedtosupportastructureofapavementsystem.Itisthefoundationforthepavementstructure.Thesubgradesoilsometimesiscalled“basementsoil”or“foundationsoil”.

Subgrade, Improved:Anycourseorcoursesofselectorimprovedmaterialbetweenthesubgradesoilandthepavementstructure.

Subgrade Resilient Modulus:Themodulusofthesubgradedeterminedbyrepeatedloadtriaxialcompressiontestsonsoilsamples.Itistheratiooftheamplitudeoftheacceptedaxialstresstotheamplitudeoftheresultantrecoverableaxialstrain.

Surface (Surface Course):Oneormorelayersofapavementstructuredesignedtoaccommodatethetrafficload,thetoplayerofwhichresistsskidding,trafficabrasion,andthedisintegratingeffectsofclimate.Thetoplayerofflexiblepavementsissometimescalledthe“wearingcourse”.

Surface Thickness (Surfacing Thickness, Surface, Slab Thickness (Rigid)):Thethicknessofsurfacingmaterial,usuallyexpressedininches.


Swell Potential:Thepercentofvolumechangedexpectedforasoilsamplewhenwetted,asmeasuredthroughlaboratorytestsconductedusingrepresentativeoverburdenpressures.

Tandem Axle Load:Thetotalloadtransmittedtotheroadbytwoconsecutiveaxlesextendingacrossthefullwidthofthevehicle.

Thermal Cracking:Crackingoccurringinpavementmaterialintroducedwithinthematerialresultingfromachangeintemperature.

Traffic Equivalence Factor:Anumericalfactorthatexpressestherelationshipofagivenaxleloadtoanotheraxleloadintermsoftheireffectontheserviceabilityofapavementstructure.

Transverse Crack:Acrackthatfollowsacourseapproximatelyatrightanglestothecenterline.

Triple (Tridem) Axle Load:Thetotalloadtransmittedtotheroadbythreeconsecutiveaxlesextendingacrossthefullwidthofthevehicle.

Truck Factor:Thenumberofequivalent80kN(18,000lb)single-axleloadapplicationscontributedbyoneusageofavehicle.TruckFactorscanapplytovehiclesofasingletypeorclassortoagroupofvehiclesofdifferenttypes.

Twenty-Year ESAL:(ESAL20)TheEquivalentSingleAxleLoadapplicationforatwenty-yeardesign.ThevalueistheproductoftheLoadEquivalencyfactorforeachvehicletype,thenumberofeachparticularvehicleperday,365daysperyear,andatwenty-yearperiod.

Upheaval:Thelocalizedupwarddisplacementofapavementduetoswellingofthesubgradeorsomeportionofthepavementstructure.

USCS:UnifiedSoilClassificationSystem.

Washboarding:SeeCorrugations.

Water Bleeding:Seepageofwaterfromjointsorcracks.

Weathering:Thewearingawayofthepavementsurfacecausedbythelossofasphaltbinder.

SECTION II - Colorado Springs · PDF fileSection 4.0 Pavement Design ... Section 6.0...

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