pavement manual

7/30/2019 pavement manual

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ENGINEERING CRITERIA MANUAL

SECTION II

Pavement Design

Criteria Manual


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Page II

TableofContents

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

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

Section3.0 LaboratoryTesting.............................. 7

3.1 SoilClassifcation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

3.2 Swell/ConsolidationTests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

3.3 SubgradeSupportEvaluation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Section4.0 PavementDesign. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.1 EquivalentSingleAxleLoad(ESAL). . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.2 SubgradeSupportCharacterization............................11

4.3 FlexiblePavementStructuralSection . . . . . . . . . . . . . . . . . . . . . . . . . . .13

4.4 RigidPavementStructuralSection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.5 MinimumPavementSections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.6 AlternatePavementDesigns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Section5.0 PavementDesignReport . . . . . . . . . . . . . . . . . . . . . . . . . 18

5.1 ReportSubmittal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5.2 Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Section6.0 ConstructionAndMaterialSpecications. . . . . . . . . . . . . . . . . . 25

6.1 HotMixAsphalt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.2 PortlandCementConcrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256.3 SubgradeandAggregateBaseCourse. . . . . . . . . . . . . . . . . . . . . . . . . . .25

6.4 MoistureTreatmentorExpansiveSoils. . . . . . . . . . . . . . . . . . . . . . . . . .25

6.5 ChemicallyStabilizedSubgrade ..............................27

6.6 MechanicallyStabilizedSubgrade. . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

6.7 ProoRolling........................................38

6.8 WaterTesting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Section7.0 Denitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39


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Page III

Tables

Table1 SubgradeClassicationTesting . . . . . . . . . . . . . . . . . . . . . . . . 7

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

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

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

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

Table6 MaterialStrengthCoecients. . . . . . . . . . . . . . . . . . . . . . . . .14

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

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

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

Table10 ScheduleforMinimumMaterialsSamplingandTesting

(MoistureTreatedSoils) ............................27

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

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

Table13 ConformitySpecications. . . . . . . . . . . . . . . . . . . . . . . . . . .34

Table14 ScheduleforMinimumMaterialsSamplingandTesting

(ChemicallyStabilizedSoils)..........................35

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

Figures

Figure1 Designchartforexiblepavements,Arterials

AllCommercial&Industrial. . . . . . . . . . . . . . . . . . . . . . . . . .21

Figure2 Designchartforexiblepavements,Local&CollectorExceptCommercial&Industrial. . . . . . . . . . . . . . . . . . . . . . . .22

Figure3 Designchartforrigidpavements,CorrectionofEectiveModulusofSubgradeReactionforLossofSupport . . . . . . . . . . . . . . . . . . . . . . . . .23

Figure4 Designchartforrigidpavements,ArterialsAllCommercial&Industrial. . . . . . . . . . . . . . . . . . . . . . . . . .24


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1.0 General

Thestructuraldesignofapavementsystemmustbedonewithaclearunderstandingofthe

factorsthataectthelifeandserviceabilityofthepavement.Therearemultiplefactorsindesignandconstructionofapavementsystem.ThisPavementDesignCriteriaManualaddressesthose

factorshavingasignicanteectonthepavementlifeandserviceability.Theobjectiveisto

obtainthebestqualitypavementsystemconsideringfactorssuchas:subgrade,tracloads,

pavementmaterial,futuremaintenanceandspecialconsiderationssuchasswellingorcollapse

pronesoils,slopeinstabilitiesandfrostsusceptiblesoils.Thedesignmustbefoundedupon

asoundtheoreticalandexperiencebasesincepublicmoniesareatriskandadirectduciary

responsibilityexists.Thisdesignmanualassumesthatallofthepartsofthepavementsection

andsubgrade,trenchbackll,hotmixasphalt,aggregatebasecourse,etc.areconstructedin

accordancewiththeCityEngineeringStandardEngineeringSpecicationsandthePikesPeak

RegionAsphaltPavingSpecications.

Thisdesignmethodologyisprescriptiveinnatureandrepresentstheminimumrequirements

ofadesign.Thephilosophyistoprovideadesignsystemwhichiseasytounderstandand

use,andallowstheDesignEngineerexibilitytoinvestigatealternatives.Alternatives,when

proposed,mustmeetminimumdesignrequirementsandhavesucientdataandanalysesto

allowCityEngineeringtoevaluatethealternatives.Theacceptanceofanydesignissolelyupto

CityEngineering.IntheeventCityEngineeringrejectsadesign,reasonsfortherejectionwillbe

providedtotheDesignEngineer.

Pavementdesignreportsandrecommendationsfornewsubdivisionstreetsaresubmittedto

theEngineeringDevelopmentReviewDivisionofCityEngineering.PavementdesignreportsandrecommendationsforCityEngineeringcapitalprojectsaresubmittedtoCityEngineerings

projectengineer.

Thedesignbasispresentedinthisdocumentisbaseduponthe1993AmericanAssociationof

StateHighwayandTransportationOcials(AASHTO)DesignGuide.Theobjectiveistoprovide

designparametersforlocalmaterialsandconditions,andtoprovideguidanceontheuseof

AASHTOequations.Thepavementdesignsobtainedfromthisprocedureshouldhaveequal

lifeandserviceabilityprovidedtheminimummaterialspecicationsaremet,construction

recommendationsarefollowed,andpropermaintenanceisprovided.Thedesignmethodology

presentedisnotmeanttopreventtheuseofalternativemethodsastechnologychangesand

additionalpavementsystemsdevelop.Furthermore,withCityEngineeringdiscretionand

approval,theColoradoDepartmentofTransportation2010PavementDesignManual,ormost

currentversion,shallbeconsideredforaccepteddesignsolutionsformethodsnotcontainedin

thisPavementDesignCriteriaManual.Throughoutthismanual,ASTMandapplicableAASHTO,or

CDOTteststandardsapplyinterchangeably.


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1.1 Design Report

TheDesignReportistoconsidertheconditionsafterdesignofthepavementalignmentand

elevation,andafterthestreetiscuttoutilitygrade(utilitygrade,orroughgrade,isdened

aswithin+/-0.2ofnalgrade).Thenatureofsubgradesoilswhichexpandorcollapsedue

towettingprovideuniquedesignproblemswhicharebestaddressedduringroughgrading

operations.APreliminaryGeotechnicalInvestigationofthestreetalignmentisappropriate

whenexpansiveorcollapsiblesoilconditionsarepresent,andwhenover-excavation,moisture

treatmentandre-compactionofthesubgradeduringmasssitegradingisexpectedtobe

appropriate.Thepreliminaryinvestigationboringsmustbelocatedinbothcutandllareas,and

mustbeproperlysurveyedforbothhorizontalandverticallocation.Boringsmustextendbelow

nishsubgradeelevationsperboringdepthsasdiscussedinSection2.0.


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3.0 Laboratory Testing

Thepurposeofthelaboratorytestingprogramistoclassifysubgradematerialandevaluate

supportpropertiesandmoisturesensitivity(heave,collapse,softening)thatcanaectlong-termpavementperformance.Testingprogramsconsistofclassicationtesting(i.e.,gradationanalysis,

AtterbergLimitsandsulfatetests)andengineeringpropertiestesting(i.e.,swell/consolidation,

R-value,unconnedcompressivestrength,CaliforniaBearingRatio,andResilientModulusTests).

3.1 Soil Classifcation

Allsamplesofthesubgradesoilsobtainedshallbetestedtoevaluateclassicationusingthe

AASHTOsystem.TheminimumrequirementsareshowninTable1.

Table 1 Subgrade Classifcation TestingAASHTOSoilClassication,AASHTOM145GroupIndexNumber

Eachsoiltypeencounteredineachboring

NaturalMoisture/Density,AASHTOT265&AASHTOT204

EachdriveorShelbysample

MaximumDryDensityandOptimumMoistureContentT99/180

Bulksampleofmaterialgoverningpavementdesign

LiquidLimit,AASHTOT89 Eachsoiltypeobtainedineachboring

PlasticLimit,AASHTOT90 Eachsoiltypeobtainedineachboring

PercentPassingNo.200,AASHTOT11 Eachsoiltypeobtainedineachboring

GradationAnalysis,AASHTOT27EachsampleofA-1toA-3soilsobtainedineachboring

SulfateTests,CDOT,CPL21031testforeach1,000linealfeetwhereA-6orA-7-6soilsarefound

SoilsshallbegroupedbasedupontheAASHTOclassicationsystemforeachbulkmaterial

foundintheupper4feetandtheGroupIndexcalculated.Whenagreaterthan7pointdisparity

inGroupIndexisnoted,thesubgradesoilgroupsshallbesubdividedintotwoormoregroups.

Thecontentofsoilgroupsshallbeplottedonaprojectdrawing.Soilswhichgovernthedesign

shallbethosehavingthehighestAASHTOsoilclassication(i.e.,A-7-6toA-2-4),lowestsubgrade

supportorhighestGroupIndex,withinthedesignlengthoftheroadway.Roadwaydesigncanbe

subdividedbasedupontheextentofsubgradematerialsfoundalongtheroadwaylength.


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3.2 Swell/Consolidation Tests

Cohesivematerials(A-4,A-5,A-6andA-7)shallbetestedtodetermineswellorconsolidation

potential.TestsshallberunonCaliforniaorthinwallShelbytubesamplescollectedfrom1foot

belowtheutilitygradeorsubgradeinaccordancewithASTMD4546ataverticalpressureof200

psf.TestingfrequencyforthesematerialsshallbeinaccordancewithTable2.

Table 2 Swell Testing Frequency

Number o Borings Testing Frequency

Lessthan5 Eachboring

5-25 Minimum5samples

Greaterthan25 Minimum7samplesor1per5borings

Thetestresultsshallbeplottedandthepercentswell/consolidationandswellpressure(psf)shallbedeterminedandreported.Testresultswhicharesuspectedofbeingnotrepresentativeof

typicalconditionsshallnotbeconsideredinthedesignofthepavementbutshallbereported.

Anydeletionofdatashallbejustiedinthewrittenreport.Theswell/consolidationpotentialfora

givensoilgroupshallbethecalculatedaverageofthegroup.

3.3 Subgrade Support Evaluation

Forthematerialgroupswhichgovernthedesign(asdeterminedinSection3.1)ofthepavement

system,compactionandstrengthtestingshallbeperformedoncompositesamplesconstructed

usingequalamountsofbulksampledmaterialswiththesameclassicationandGroupIndex

rangespecicationinaccordancewithTable3.

Table 3 Subgrade Strength Evaluation

Subgrade Compaction and Strength Testing

UnconnedCompressiveStrengthTestonremoldedsample,compactedat2%aboveProctoroptimummoisturecontentinaccordancewithAASHTOT99,orCaliforniaBearingRatioonremoldedsample(AASHTOT193)compactedat2%aboveProctoroptimummoisture

content.orHveemStabilometer(R-value),AASHTOT190

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

StandardProctorCompaction,ASTMD698ModiedProctorCompaction,AASHTOT180

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


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Thedesignsoilsupportvalueshallbedeterminedtobethelowestvalueobtainedfromthe

testing.IntheeventtheDesignEngineerelectstoremoveandreplacethelowestsupportvalue

toaminimumdepthof2feetbelownishsubgrade,thesupportvalueofthereplacementllcan

beused.Technicaljustication(calculations)fortheremovalandreplacementshallbeprovided

inthereport.


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4.0 Pavement Design

Thedesignmethodologyisbaseduponthe1993AASHTODesignGuideequationsandconsiders

TracandSubgradeResilientModulusastheprimaryvariables.TracloadingrequirementsarepresentedinSection4.1.TheSubgradeResilientModulusandswell/consolidationanalysis

shallbedeterminedinaccordancewithSection4.2Thedesignequationsforexibleandrigid

pavementsarepresentedinSection4.3and4.4.Alternativeswillbeconsideredwithadvances

inpavementdesignmethodsandpavingmaterialchanges.Anydeviationfromguidelines

presentedinthisdocumentmustbetechnicallyjustiedandapprovedbyCityEngineering.

4.1 Equivalent Single Axle Load (ESAL)

Oneofthefactorsusedinpavementdesignistheloadingoftracontheroadway.Thisisa

combinationofthevolumeoftracandtheweightofthevehiclesonthestreet.Thisfactoris

describedintermsof18,000-poundEquivalentSingleAxleLoadsorESALs.Thecalculationof

ESALsisbasedonthefollowinginformation:

- ADT

- Lanedistribution

- Truckvolumes

- Truckweightsandaxlecongurations

Sincethisinformationisnotreadilyavailableforallstreets,thismanualprovidesdefaultESAL

valuesforCitystreetclassicationsandCity-widetruckvolumeestimates.TheESALvaluestobe

usedforstreetclassicationsareshowninTable4.

PavementdesigncanbecompletedusingaroadwayspecicESALvalue.ESALcanbecalculated

usingthetechniquedescribedintheColoradoDepartmentofTransportation(CDOT)mostrecent

PavementDesignmanual.Thecalculations,inputdata,andanyassumptionsmustbereviewed

andacceptedbyCityEngineering.

Table 4 City Street ESAL Deault 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-laneESALvalueswhichmaynotbereducedordirectionaltravelorlanedistribution.


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4.2 Subgrade Support Characterization

Subgradecharacterizationconsistsofevaluatingsubgradeandlong-termsupportvalues.The

degreeofmoisturesensitivityanddeectionsensitivityisusedtoevaluatethedepthofmoisture

treatmentappropriatetoreducethedeectionatthesurfaceofthecompletedpavementsystem

ThesupportvalueisexpressedintheformofaResilientModulusasdeterminedfromunconned

compressivestrength,R-value,orCBRtesting.

1. Expansive Subgrade-Testsperformedtodetermineswell(expansion)potentialin

accordancewithSection3.2shallbeaveragedforeachsoilgroup.Forthehighestaverage

swell,thedepthofmoisturetreatmentshallbedeterminedinaccordancewithTable5.

Usingengineeringjudgment,locallydieringvaluesshallbeaddressedinthetextofthe

reportundertheappropriatesubgradediscussionsection.

Table 5 Depth O Moisture Treatment For Expansive Soils

Swell % at 200 psSubgrade SoilLiner Samples

Depth o Moisture Treatment (eet)

Non-Arterials Arterials


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a. ChemicalStabilization-Chemicalstabilizingagentsincludelime,yash,

combinationsoflime/yash,andlime/Portlandcement.Otheragentsor

combinationscanbeusedwithapprovalbyCityEngineeringandprovidedthemix

designrequirementsaresatised.Laboratorymixdesignsshallmeetthefollowing

criteria:

1. ForLimetreatmentthepHshallbeequaltoorhigherthan12.3beforecompaction(notrequiredwhereswellislessthan4percent)

2. UnconnedCompressiveStrengthbetween160psiand700psi(ASTM2166)

3. Swelllessthanonepercentat200psf(ASTMD4546)

Whenlimeisused,PlasticityIndexistobereportedfrominitialtonalconstruction

toallinterestedparties(e.g.,StabilizationContractor,GeotechnicalEngineer

andCityInspector)andshallnotbeusedforacceptancepurposes.Thedesign

stabilizingagentpercentageasdeterminedbythedesignershallbeincreased

by1.0percentintheeldtoaccountforwaste,inertmaterials,andconstructionvariability.

Ifwatersolublesulfatecontentsexceed0.2percent,thetreatmentshallbe

accomplishedusingadoubleapplicationmethod.Adoubleapplicationmethod

consistsofaninitialtreatmentofLimeandallowingittomellowforaminimum

periodof7days(withconstantwetting).Afterthemellowperiod,thesubgrade

shouldbemechanicallymixedpriortoapplyingtheremainingpercentageof

chemicalstabilizer(Lime,FlyAshorCement).Thisshallbepresentedanddiscussed

inthedesignreport.Allchemicalstabilizationshallbeperformedinaccordance

withSection6.5.

b. MechanicalStabilization - Soft,yieldingsoilsmaybestabilizedmechanicallyusinggeogridsinconjunctionwithaggregatebasecourseorrecycledconcretetoprovide

astableconstructionplatform.Allmechanicalstabilizationshallbeperformedin

accordancewithSection6.6.

3. Resilient Modulus-Subgradesupportcharacteristicsusingthe1993AASHTOdesign

methodologyconsidertheResilientModulus(Mr).Equipmenttodirectlydetermine

theResilientModulusmaynotbeavailabletosomelocalrms.Aseriesofcorrelations

andalternativeequationsareprovidedtoaidrmsthatdonothavetheappropriate

equipmenttoestimatethedesignMr.equationstoestimatevaluesusingR-value

fornon-cohesivesubgradematerials,amodiedunconnedcompressivestrength

procedureorCBRforcohesivesubgradematerialsareincludedwiththisdocument.Thesubgradestrengthcharacteristicsshallbeevaluatedinaccordancewiththerequirements

ofSection3.0LaboratoryTesting.ThesevaluescanbeconvertedintoResilientModulus

usingthefollowingequations:


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UnconnedCompressiveStrength

(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 = unconined compressive strength in ps

CaliforniaBearingRatio

Mr= (CBR) x 1500

HveemStabilometer(RValue)

Mr= 10

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

4.3 Flexible Pavement Structural Section

Thethicknessofthepavementsectionshallbedeterminedusingthedesigntrac20-year,18-kip

ESALsobtainedfromSection4.1,theResilientModulusobtainedfromSection4.2.3andthe

depthofmoisturetreatmentandstabilizationobtainedfromSection4.2.1and4.2.2.

TheStructuralNumber(SN)shallbedeterminedusingtheAASHTO1993designmethodologyor

usingthedesignnomographsprovidedinFigure1withtheinputparameterspresentedinTable

6.UsingstrengthcoecientsprovidedinTable7,calculatethethicknessofthevariouspavement

layersbythefollowingformula:

SN = a1(D1) + a2(D2) + . . . + an(D n)

Where:

a1 = Strength coeicient or HMA

a2, a3, a4an = Strength coeicient or lower layers

D1 = Thickness o HMA

D2, D3, D4Dn = Thickness o additional layers

S+18.726.24


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Table 6 Material Strength Coecients

Material Coecient (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) 0.44forexiblepavements

InitialServiceability=4.5ServiceabilityLoss(PSI)

2.5Locals,collectors,privatedrives,parkinglotsandpublicalleys2.0Arterialsandallcommercialfrontageandindustrialroadways

4.4 Rigid Pavement Structural Section

ThethicknessofthepavementsectionshallbedeterminedusingthetracESALsobtainedfrom

Section4.1,ak-value,thedepthofmoisturetreatment,andstabilizationobtainedfromSection

4.2.1and4.2.2.Forrigidpavementdesign,theResilientModulus(Mrinpsi)mustbeconvertedto

aModulusofSubgradeReaction(k-Valueinpci)usingthefollowingformula.

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

Theeectivek-valuecanbedeterminedbycorrectingforLossofSupport(LS)(Figure1)withthe

followingassumptions:

LS = 0 or concrete over an existing pavement

LS = 1.0 or Chemically Treated Subgrades

LS = 2.0 2.5 or Natural Subgrade Materials


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ThedesignthicknessshallbedeterminedusingtheAASHTO1993designmethodologyorusing

thedesignnomographsprovidedinFigure3and4withtheinputparameterspresentedinTable

8.

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(Sc) 650psi

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

InitialServiceability=4.5ServiceabilityLoss(PSI)

2.5Local,collectors,privatedrives,parkinglotsandpublicalleys2.0Arterialsandallcommercialfrontageandindustrialroadways

Jointspacing,dowelingandtiebarsshallbeinaccordancewithAmericanConcretePavement

AssociationrecommendationscontainedinDesignandConstructionofJointsforConcreteStreets.Dowelsarerequiredforindustrialandarterialstreetsforlongitudinalandexpansion

joints.

4.5 Minimum Pavement Sections

IfthecalculatedpavementsectionsindicatesectionsthinnerthantheMinimumPavement

SectionsshownbelowinTable4.5.1,theMinimumPavementSectionsshallgovern.TheCity

Engineerpreferstheuseofexiblepavementdesignedasacompositesectionofhotmixasphalt

overaggregatebasecourse.Fulldepthpavementsections(exibleorrigid)areallowedsubjectto

sucientjusticationoverchemicallytreatedsubgrade,orsuitablesubgradeasdenedherein.

Fulldepthpavementisnotallowedovermechanicallystabilizedsubgrade.Certainverysandy

subgradeconditionsmayrequireapplyinganon-structuralcoveringofaggregatebasecoursefor

constructabilitytosupportthepavingequipment.TheCityEngineermayincreasetheminimum

pavementsectionatanylocationifconditionswarrant.FollowinginTable9aretheminimum

pavementthicknessesrequiredbyCityEngineering:


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Table 9 Minimum Pavement Thicknesses (inches)

Flexible PavementRigid

Pavement

Classifcation 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.CTSsectionasapprovedbytheCity

3.TheminimumthicknessoABCshallbesixinchesinanyapplication

ABBREVIATIONS: HMA=HotMixAsphalt

ABC=AggregateBaseCourse

CTS=ChemicallyTreatedSubgrade

PCCP=PortlandCementConcretePavement

4.6 Alternate Pavement Designs

CityEngineeringunderstandstheneedtoconsideremergingtechnologiesinpavementdesign.

Inlightofthis,anyalternatepavementdesignwillbereviewedandconsideredwithrespectto

thefollowingcriteria:

- Initialconstructioncost

- Lifecyclecost

- Constructiondelayandimpact

- Facilitymaintenanceandeaseofrepair

- Pavementnoise,smoothness

- Industrycapacityandlocalcontractorcapability

- Specialdesignprovisionssuchasedgedrainsbehindthecurbs1tointerceptmoisturefrom

adjoiningdevelopmentandpreventitfromadverselyaectingtheroadsubgradeand

pavingsection.


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CityEngineeringreservestherighttomakethepavementtypeselectionusingtheseand/orothe

criteriaonCityfundedprojects.

1Special Drainage Considerations:Thedesignengineershouldanticipatethefuture

developedconditionofthelandadjacenttotheroadwaywhenmakingthepavingdesign

recommendations.Evenwhennoshallowgroundwaterispresentinthepre-developedcondition

itisexpectedthatcertainlandusessuchassinglefamilyhomesandprojectswithirrigated

landscapingpresentthepossibilityofwaterenteringtheroadsubgradeandadverselyaecting

theperformanceandlongevityofthepavement.Cityforceshavetoinstallretrotunderdrain

systemsinmanystreetstomitigatethesekindsofproblems.Appropriaterecommendationsand

designfeaturestostopwaterfrominltratingintothepavementsectionwillreceivepositive

responsefromCityEngineering.


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5.0 Pavement Design Report

Allpavementdesignreportsshallbepreparedbyorunderthesupervisionof,andstamped

andsignedby,aProfessionalEngineerlicensedintheStateofColoradoandpracticingasaGeotechnicalEngineer.

5.1 Report Submittal

DesignreportsshallbesubmittedtoCityEngineering.Pavementdesignreportsfornew

subdivisionstreetsaresubmittedtotheEngineeringDevelopmentReviewDivisionofCity

Engineering.PavementdesignreportsforCityEngineeringcapitalprojectsaresubmittedtoCity

Engineeringsprojectengineer.Allreportsshallcontainthefollowingitems:

- Descriptionoftheareaoftheprojectincludingthelocationlanduse,surfaceconditions,

topography,sitegrading,extentofsitedevelopmentatthetimeofinvestigation,vegetation,andanyunusualsurfacefeatures.

- ListingofthesamplingandtestingtechniquesandappropriateAASHTOorASTM

designations.

- TableshowingAASHTO,USCSandGroupIndexoftheindividualsubgradesamplesfound

withinthedrillingdepthsandofthegroupswhichgovernthepavementdesign.

- Subgradesupporttestingsectionsshallincludegraphsofmoisture/densityrelationtests,

R-values,CBRtests,unconnedcompressivestrength,swell/consolidationtestsandother

testsdeemedtobeapplicablefortheconditionsfoundperformed.Thesubgrade-support

testresultsshallbeshownalongwiththeresultingcalculatedResilientModulusork-Value

andtheequationsusedtodeterminethevalue.

- Wheremoisturesensitivesubgradesoilsoccur,thedepthofmoisturetreatmentand

subgradestabilizationotherthanthedepthdeterminedfromSection4.2.1shallbe

discussedandtheanalysisshown.

- Wheretreatmentisrequiredduetoexpansivesoils(Section4.2.1),astabilizedsubgrade

isrequired(Section4.2.2)andareportshalldeterminethestabilizingagenttobeused.

Anystabilizingagentsnotlistedmustbepre-approvedbyCityEngineering.Special

stabilizationtechniquesrequiredduetohighwatersolublesulfatecontentsorother

conditionsshallbepresented.Wheresoilscontainsolublesulfatesinconcentrations

greaterthan0.2percent,adiscussiononadoubleapplicationmethodandsulfateresistanconcreteshallbepresented.Shouldanyofthesesoilsbestabilized,specialconstruction

precautionsshallbepresented(i.e.,stagedconstruction).

- ThedesigntracintermsofESALsshallbepresentedonagureanddiscussedinthe

designreport,includingthesourceoftracinformation.


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- Designpavementthicknessesincludinghotmixasphalt,Portlandcementconcreteor

compositesectionsshallbeshownonagureforthevariousstreetsections.Ifcomputer

softwareisusedtodevelopsolutions,theprintoutfromthesoftwareshallbeincludedin

thereport.Ifnomographsareused,theyshallbeincludedinthedesignreportforeach

soilgroupandtracloadingcondition.

- Adiscussionofdesignandconstructionconcernsshallbepresented,followedbyspecic

recommendationstomitigatetheconcerns.Factorssuchas,butnotlimitedto,swelling

heave,frostheave,collapsingsoils,dicultexcavations,steeplydippingbedrock,organic

soils,highwatertable,medianlandscaping,lowdensity,collapsepronesoils,orutility

trenchsettlementeectsmustbepresented,discussed,andmitigationrecommendations

presented.

- Wheretwominorarterialorhigherclassicationstreetsintersect,thedesignshould

considerthecombinedtracvolumes.TheuseofPortlandCementConcretePavement

athightracvolumeintersectionsmaybedeemednecessarybyCityEngineering.High

volumeasphalticconcretemayalsobeappropriate.CityEngineeringwilldeterminetheextentofthehighvolumeintersectiontreatments.

- Thereportshallincludeadiscussionofmaterialrequirementstomeetthedesign

assumptions.ThereportshallrefertoappropriateCityofColoradoSpringsand

PikesPeakRegionmaterialandconstructionspecications.Hotmixasphaltdesign

recommendations,inaccordancewiththeCityofColoradoSpringsandthePikesPeak

RegionAsphaltPavingSpecications,shallalsobeincluded.CDOTrequirementsmayalso

applyforhightracintersections.

- Additionalconcernswithrespecttodesign,construction,maintenance,andotherproject

aspectsshouldbepresentedanddiscussed.

- Forsubdivisionstreets,anyissuesidentiedintheGeologicHazardStudyrelatingtosoil

stabilityorspecialdesignrequirementsmustbediscussed.

- ReferenceList

5.2 Figures

Toevaluatethedesign,guresarenecessarytopresentinformationanddesigndata.Allreports

musthavethefollowing:

1. Project location including:

a. Avicinitygureshowingtheprojectlocationusingexistinglandmarks,roadways.

b. Locationofexploratoryboringsandtheestimatedextentofsubgradesoiltypesby

soilgroupsandAASHTOclassications.

2. Graphical representation o exploratory borings:

a. GraphicalboringlogsshallberepresentedusingAASHTOclassicationsfor

materials.Bedrockshallberepresentedinaccordancewithlocalpractice,i.e.,

sandstone,claystone,interbeddedbedrock,weatheredclaystone.

b. Theboringlogsshallalsoprovidethefollowing:


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1. Samplingdepthsandlength,includingblowcount,pushdepth,andrecovery

2. Moisturecontent,drydensity,percentswell/consolidationundera200psfpressure

3. AtterbergLimits(liquidlimit,plasticityindex)

4. PercentpassingtheNo.200sievec. Figuresshowingswell/consolidation,moisture/densityrelations,unconned

compressivestrength,andresultsofHveem/stabilizationorCBRtesting.

d. Designpavementsectionalternativesandspecialalternatives

3. Recommended Pavement System:

a. Thedesignalternatives,baseduponengineering,shallbepresentedona

RecommendedPavementAlternativesgure,illustratingtheextentofeach

alternativepavementsectionalongwithalegenddescribingeachpavement

alternative,thedesignESAL,andthesubgradegroupusedforthedesign.

b. Specialconsiderationssuchassoftsoils,organicmaterials,treatmentsshallbepresentedontheRecommendedPavementAlternativesgure.

c. Structuressuchasbridges,boxculverts,interchanges,andturnlanesshallbe

shownonallsitegures.

d. Wherelaneshavedierentpavementsections,thevariationsshallbeclearlyshown

ontheRecommendedPavementAlternativesgure.


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Figure 1 Design chart or fexible pavements


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Figure 2 Design chart or rigid pavementsLocal & Collector


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Figure 3 Design chart or rigid pavements


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Figure 4 Design chart or rigid pavements


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6.0 Construction And Material Specifcations

Theintentistospecifymaterials,equipment,methodsandstandardstobeusedforthe

constructionofpavementsystemsasindicatedontheplans.Thedesignintentistoconstructapavementwithadequatethicknessandqualitytoprovideaserviceablelifeofatleast20years.All

workmanshipandmaterialsshallbeinaccordancewiththerequirementsofthesespecications

andspecialprovisions,andinconformitywiththelines,grades,quantitiesandtypicalcross

sectionsshownontheplansorasdirectedbyCityEngineering.

6.1 Hot Mix Asphalt

Allhotmixasphaltmustmeetthematerialspecicationsandconstructionstandardspresentedin

thecurrentversionofthePikesPeakRegionAsphaltPavingSpecications.

6.2 Portland Cement Concrete

AllPortlandcementconcretemustmeetthematerialspecicationsandconstructionstandards

presentedinthecurrentversionoftheCityofColoradoSpringsCityEngineeringStandard

SpecicationsManual.

6.3 Subgrade and Aggregate Base Course

Allpreparedsubgradeandaggregatebasecourse,includingrecycledconcrete,mustmeetthe

materialspecicationsandconstructionstandardspresentedinthecurrentversionoftheCityof

ColoradoSpringsCityEngineeringStandardSpecicationsManual.Aggregatebasecourseshallextendtothebackofcurbasaminimum.

6.4 Moisture Treatment or Expansive Soils

Thisworkconsistsofremoving,moistureconditioning,replacing,compaction,andshaping

theexistingexpansivesubgradewithmoistureanddensitycontroltotheextentshownonthe

plans.Thepurposeistoprovideazoneoflowswelling,strainabsorbingmaterialbetweenthe

expansivesubgradeandthepavementsection.Moisturetreatmentshallextendtothebackof

curbasaminimum.Thedepthofremovalandreplacementwithmoisturetreatedsubgradeshall

beconsistentwiththeplansregardlessofcut,llorbackll.


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1. Equipment -Thecontractorshallprovideequipmentingoodoperatingcondition

thatisspecicallydesignedandmanufacturedforthepurposeofexcavating,hauling,

mixing,watering,levelingandcompactingsubgradematerials.Mixingandwatering

equipmentshallbecapableofachievingauniformmoisturecontentwithoutwetor

dryzones.Compactionequipmentshallbeadequatelydesignedtoobtaincompaction

requirementswithoutadverseshoving,rutting,displacementorlooseningofsubgrade

material.Theequipmentshallbeavailabletoperformtheworkspeciedwithinthetime

framesrequiredandtobecoordinatedwithotheractivities.Theequipmentshallbe

operatedbyskilledworkmanatanormalproductionrateforthespeciedtypeofwork.

Allequipmentandmachineryshallbekeptingoodworkingorder,freeofleaksand

properlymued.Alltaxes,licensesandfeesshallhavebeenpaidandproperlicensesand

permitsshallbepostedasrequiredbylaw.

2. Construction Methods

a. Compaction-Theexistingsubgradeshallberemoved,uniformlymoisturetreated,

mixed,replaced,andcompacted.Eachlayershallbecompactedtoatleast95percentStandardProctordensityasdeterminedbyAASHTOT99at1to3percent

aboveoptimummoisturecontent.Thethicknessoflayers,priortocompactions,

shalldependuponthetypeofsprinkling,mixingandcompactingequipmentused.

Moisture/densitytestsshouldbeperformedevery250linearfeet,alternatinglanes,

toverifysubgradedensitymeetsspecications.

Aftereachlayeroflliscomplete,testsmustbemadetoconrmmoisturecontent

andrequiredcompaction.Whenthematerialfailstomeetthecompactionor

moisturerequirementsorshouldthemateriallosetherequiredcompactionor

moistureornishbeforethenextcourseisplacedortheprojectisaccepted,the

layershallbeprocessed.Reprocessingshallbedoneatthecontractorsexpense.

Thecontractormayberequiredtoexcavateanareaofthelayerinordertofacilitate

thetakingofdensitytests.Replacementandcompactionoftheremovedmaterial

intheareashallbeatthecontractorsexpense.

b. SubgradeStabilization-Moisturetreatmentwillleaveasoftyieldingsubgrade

unsuitableforpaving.StabilizationinaccordancewithItem4.2.2,Subgrade

Stabilization,shallbeperformedtothedepthsandlimitsshownontheplans.

3. Tolerances

a. GradeTolerances-Anydeviationinexcessof1/2inchincrosssectionand1/2

inchin10feetmeasuredlongitudinallyshallbecorrectedbyloosening,adding

orremovingthematerial,reshapingandre-compactingbysprinklingandrolling.Deviationsinexcessofthistoleranceshallbecorrectedbythecontractor,atthe

contractorsexpense,inamannersatisfactorytoCityEngineering.

b. CompactionTolerances-Compactionbelowthespeciedminimumshallbe

correctedbyre-compaction.Inadequatecompactionshallbecorrectedbythe

contractor,atthecontractorsexpense.


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c. MoistureTolerances-Anylossofmoisturebelowthesetlimitsshallbecorrectedby

moistureconditioningandre-compaction.Lossofmoistureshallbecorrectedby

thecontractor,atthecontractorsexpense.

4. Testing and Inspection

a. TestingofmoisturetreatedsoilsshallbeperformedinaccordancewithTable10.

Table 10 Schedule or Minimum Materials Sampling and Testing

(Moisture Treated Soils)

Test Type Test Standard Minimum Frequency o Tests

InPlaceSoilDensityAndMoistureContent

AASHTOT191ASTMD2167AASHTOT238ASTMD2216AASHTOT239

Onetestforeach250lanefeet(notlessthanonetestperday).

LiquidLimit AASHTOT89 Onetestpersoiltype

PlasticLimit AASHTOT90 Onetestpersoiltype

Moisture-DensityRelationships

AASHTOT99AASHTOT180

Onetestpersoiltype

6.5 Chemically Stabilized Subgrade

Thisworkconsistsofthecontractorconstructingoneormorecoursesofamixtureofsubgrade

soil,approvedstabilizingagentandwaterinsubstantialconformitywiththedesignline,grades,

thicknesses,andtypicalcrosssectionsshownontheapprovedplansandtheapprovedpavement

thicknessdesign.Purpose -Thepurposeoftheworkshallbetoprovideastructuralsectionon

whichpavingmaterialscanbeplacedandtomeetdesignspecications,whileatthesametime,

protectingtheunderlyingmoisture-treatedsubgradesoils.Subgradestabilizationshallextend

tothebackofcurbasaminimum.Thisspecicationcanalsobeappliedtoachieveastabilized

pavingplatformwithoutstructuralbenets.

1. Materials

a. StabilizingAgents-Thepre-approvedstabilizingagentsarelistedinTable11.

Variouscombinationsofthesematerialsmayalsobeused,subjecttoasuitablemix

design.OtheragentsmaybeusedwithpriorwrittenapprovalofCityEngineering.


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Table 11 Approved Chemical Stabilizing Agents

Pre-Approved Stabilizing Agents

Agents Must conorm to requirements o

Lime ASTM C977,C110

FlyAsh(CandF) ASTM C618

CementKilnDust ASTM D5050

PortlandCement ASTM C114

High-calciumquicklimeshallconformtotherequirementsofASTMC977andrate

ofslakingtestshallproduceatemperatureriseof20Cin30secondsand35Cin3

minutesperASTMC110.Dolomiticquicklime,magnesiaquicklimewithmagnesium

oxidecontentsinexcessof4percentorcarbonatedhydratedlime,shallnotbe

used.High-calciumquicklimemustbeappliedinslurry.

FlyashmayconsistofClassCorClassF.ClassFyashshallonlybeallowedinconjunctionwithlimeorothercementitiousstabilizingagents.

Allstabilizingagentsshallcomefromthesamesourceasusedinthedesign.If

thesourceischanged,anewdesignmustbesubmittedtoCityEngineeringfor

approval.Eachlotofstabilizingagentfurnishedshallhavethesupplierscerticate

ofcompliance.

b. b.Water-Waterusedformixingorcuringshouldbefromapotablesource.Inthe

eventpotablewaterisnotused,non-potablewatershallbetestedinaccordance

withandmeettherequirementsofAASHTOT26andusedinthemixdesign.

c. c.Subgrade-Thesubgradematerialtobestabilizedshallbefreeofroots,sod,

weeds,wood,constructiondebris,ice,snow,orotherfrozenmaterials,deleteriousmatter,andstoneslargerthan3inchesinsize.Materialinthestabilizedzoneshall

haveawatersolublesulfatecontentoflessthan0.2percentasperCPL2103,

MethodB.Ifthesubgradesoilshaveasolublesulfatecontentexceeding0.2

percent,themixdesignshalladdressthespecicmethodologyusedtoprevent

adverseeectsofsulfatereactions(e.g.heavingsubgrade,crackedpavement).

2. Equipment - AllequipmentshallbesubjecttoapprovalbyCityEngineering.All

equipmentandmachineryshallbekeptingoodworkingorder,freeofleaksandproperly

mued.

a. DryApplicationEquipment-Equipmentforspreadingdrystabilizingagentshallbe

ofanapprovedscrew-typespreaderbox,mixer,orothersemi-enclosedequipmentwhichisequippedwithameteringdevice.Spreadingofstabilizingagentsby

aggregatespreadersormotor-graderswillnotbeallowed.

b. SlurryApplicationEquipment-Adistributorortruckapplicatorshallbeused

andbecapableofcontinuousagitationtokeeptheslurrymixtureuniform.The

applicatorshallbecapableofuniformlymeteringthestabilizingagentduring

application.


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c. MixingEquipment-Mixingequipmentshallbeofsucientsizetoadequately

mixthestabilizingagentintothesoilandtopulverizethemixture.Thesizeofthe

mixershallbeadequatetomixandpulverizethemixturetoaminimumdepthof12

inchesinasinglepass.Blades,discs,andsimilarequipmentarenotallowedwithou

priorwrittenapprovalofCityEngineering.

d. CompactionEquipment-Compactionequipmentshallbeingoodworkingorder

andofsucientsizeandeectiveforcetoachievetherequiredcompactiveeort.

3. Construction Submittals - Atleast15dayspriortocommencingstabilizationwork,the

contractorshallfurnishthefollowinginformationtoCityEngineering:

- Thesourceandsupplierofstabilizingagentandcertications,includingpurity

ofstabilizingagent,fromthemanufacturerstestingagencyindicatingthatthe

stabilizingagentmeetstheappropriaterequirements.

- Descriptionoftheproposedconstructionequipment,constructionmethods,

expectedproductionratesandplannedsequenceofconstruction.

- AmixdesigngivingtheWaterSolubleSulfatetestresultspercentageofstabilizingagent,sourceoftheagent,propertiesandanyspecialconsiderations.

Foreachdayswork,thecontractorshallfurnishthefollowinginformationtotheCity

EngineeringInspectorbythefollowingday:

- Certiedtruckweightticketsofstabilizingagent,deliveredorusedatthesite.

- Asummaryoftheamountofstabilizingagentusedeachday,areasstabilizedand

rstmixed,areassecondmixedandcompacted,andareaswithcuringcompleted.

- Priortopaving,nalinplacesoilpropertiesperTable6.5.11.

4. Stabilized Mix Design

MixdesignsshallbeperformedunderthesupervisionofandsignedbyaProfessional

EngineerlicensedtopracticeintheStateofColoradopracticingasageotechnical

engineer.MixdesignshallcomplywiththerequirementsofTable12

Table 12 Stabilization Mix Design Requirements

Stabilization Mix Design Requirements

StabilizationAgent

MinimumpH

(Notes 1 & 2)

Maximum SwellPotential (%)

(Note 3)

Minimum UnconfnedCompressive 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


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1. SlurryPlacement-Thedistributionofstabilizingagentshallbeattainedbysuccessiveapplicationsoverameasuredsectionofsubgradeuntiltheproperamountofagenthasbeenspread.Theamountspreadshallbetheamountrequiredformixingtothespecieddepth,whichwillresultinthepercentagedeterminedinthedesign.Whenquicklimeisusedinplaceofhydratedlime

theamountofquicklimeusedwillbedeterminedbythecertiedlimepurityforeachloadsuppliedasfollows:

Quicklime delivered X % purity * 1.32 = A

Quicklime delivered *X % inert material = B

A + B = total hydrated lime available

Note:Whenadoubletreatmentoflimeisrequired,therst50percentoftheagentshallbeplaced,moisturetreatedandallowedtomelloworcureforuptothreeweeks,asdeterminedbytheDesignEngineer.Thelasthalfofthelimeshallthenbeapplied.

2. DryPlacement(ThismethodcanonlybeusedforFlyAsh,cementkilndust,

andPortlandcement)-Theamountofstabilizingagentspreadshallbetheamountrequiredformixingtothespecieddepth,whichwillresultinthepercentagespeciedbythedesign.Thestabilizingagentshallbedistributedinsuchamannerthatscatteringbywindwillbeminimal.Agentsshallnotbeappliedwhenwindconditions,intheopinionofCityEngineeringsinspector,aredetrimentaltoaproperapplication.Theblendedmaterialshallbesprinkledorwatereduntilmoisturecontentisasspeciedinsubgradestabilizationdesign.Thecombinationofstabilizingagent,soilandwatershallbecalledthemixture.Afterspreadingofstabilizingagentandduringmixing,watershallbeaddedtohydratetheagentandfordustcontrol.

b. HighSulfateTreatment-Wheresulfatesareover0.2percentthedesignermust

addressthemethodoftreatment.c. Mixing-Nostabilizationshalltakeplacewhenprecipitationmaycausedamageto

thesubgrade.Mixingshallbecontinuous.Thefulldepthofthetreatedsubgrade

materialshallbemixedwithanapprovedmixingmachinetothespecieddepth

belowthebottomofthepavementstructureand/orcurb.Themixingmachine

shallmakeasucientnumberofpassestoadequatelyachieve100percentofthe

materialpassingtheone-inchsieveand60percentpassingthe1/4-inchsieve.

Watershallbeaddedtothesubgradeduringmixingtoprovideamoisturecontent

ofatleast3percentabovetheoptimummoistureofthemixtureorasspeciedin

subgradestabilizationdesign.Mixingandremixingwillbeperformed,asnecessary,

toassistthestabilizingagent-soilreactionandproduceahomogeneousmixture.

Mixingandremixingshallcontinueuntilthecombinationofstabilizingagentandsubgradematerialisfreeofstreaksorpocketsofstabilizingagent.


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d. Mellowing(LimeorLime/FlyAshOnly)-Themoisturecontentofthesubgrade

mixtureshallbemaintainedaboveoptimumforaminimumof2daysanduntilthe

subgradestabilizationdesigncriteriaismet.Remixingwillbedoneasnecessary

toassistthereaction,asdeterminedbythedesignengineer.Applicationofwater

shallbeperformedasnecessaryduringthemellowingperiod;thematerialshall

maintainamoisturecontentofatleast3percentaboveoptimum.Thestabilizedmaterialshallnotbesubjectedtotrac.Ifduringthemellowingperiodthe

materialisnotinasemi-loosestate,thechemicalreactionprocessmayslowand,

therefore,requireadditionaltimeand/ormixingasdeterminedbythedesign

engineer.

e. FinalMixing(LimeorLime/FlyAshOnly)-Finalmixingofthetreatedsubgrade

shallnotoccurifthetemperatureofthesoiltobestabilizedisbelow40F.The

treatedsubgradeshallbemaintainedatatemperatureof40Foraboveuntil

thetreatedmaterialhasbeencompacted.Thematerialshallbeuniformlymixed

byanapprovedmethodtomeetthefollowingrequirementswhentesteddryby

laboratorysieves:

Sieve SizeMinimum Percent

Passing

1-inchsieve 100

No.4sieve 60

6. Compaction -Compactionofthemixture,forthefulldepthofthestabilizedsubgrade

shownontheplans,shallbeginassoonaspracticalafternalmixing.Stabilized

subgradewithcementitiousstabilizationagentshallbecompletedwithin90minutes

ofthetimethecementitiousstabilizationagentandwateraremixed.Theelddensity

ofthecompactedmixtureshallbeatleast95percentofthemaximumdrydensityoflaboratoryspecimenspreparedfromsamplestakenfromthetreatedsubgrade

materialimmediatelypriortocompacting.Thespecimensshallbecompactedand

testedinaccordancewithASTMD698orASTMD558,asspeciedinthesubgrade

stabilizationmixdesign.Thein-placeelddensityshallbedeterminedinaccordance

withASTMD1556,ASTMD2167orASTMD2922.Themoisturecontentofthemixture

ofshallbebetween0to3percentabovetheoptimummoisturecontent.Theoptimum

moisturecontentshallbedeterminedinaccordancewithASTMD698orASTMD558,

asspeciedinsubgradestabilizationdesign.Initialcompactionshallbedonebymeans

ofasheepsfootorsegmentedwheelroller.Finalcompactionshallbebymeansofa

smoothwheelorpneumatictiredroller.Areasinaccessibletoamechanicalrollershallbecompactedtotherequireddensitybyothermeansacceptabletothedesignengineer.All

irregularities,depressions,orweakspotswhichdevelopshallbecorrectedimmediately

byscarifyingtheareasaected,addingorremovingmaterialsasrequired,andreshaping

andre-compactingbymoistureconditioningandrolling.Addingadditionalstabilized

materialtoaninitialcuredsection,resultinginlaminationandpotentialslipplane,isnot

allowed.Thesurfaceofthecourseshallbemaintainedinasmoothcondition,freefrom


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undulationsandruts,untilotherworkisplacedthereonortheworkisaccepted.Should

thematerial,duetoanyreasonorcause,losetherequiredstability,density,andnish

beforethenextcourseorpavementisplaced,itshallbecorrectedandrenishedatthe

soleexpenseofthecontractor,asdirectedbyCityEngineering.

7. Finishing and Curing - Afterthenallayerofstabilizedsubgradehasbeencompacted,theshapeofthesurfaceshallbeachievedbyblading.Thesurfaceshallbesmooth

andconformtotherequiredlines,sections,andgrades,inaccordancewiththeplans

andthoroughlycured,ortowithinaminimumof0.1footabovethenishedsubgrade

elevationtoallowfortrimmingtonalgradepriortoplacementofsurfacecoarse.

Thecompletedsectionshallthenbenishedbyrollingwithsuitablepneumatictired

equipmentwithsucientlylighteorttopreventhairlinecracking.Curingmaybe

accomplishedbyperiodicwaterapplicationtomaintainmoisturecontentpreventing

sloughingorcrackingofthesurfaceofthestabilizedsubgradetoadepthnogreaterthan

0.1foot,orbytheutilizationofabituminousseal.Whenbituminoussealisutilized,the

minimumapplicationwillbeattherateof0.12gallonspersquareyard,asdirectedandapprovedbythedesignengineer.Thecompletedsectionshallbecuredforaminimum

of5daysbeforefurthercoursesareaddedoranytracispermitted,unlessotherwise

permittedbythedesignengineer.Themoisturecuredurationmaybereducedifa

non-yieldingsurfaceisobtainedtosupportconstructiontracandeitherthenext

layerofstabilizedsoilsareplacedorthepavementlayerisconstructed,asapprovedby

theEngineer.Ifthesurfaceofthenishedlayerisabovetheapprovedplanelevation

tolerancespeciedinthissection,theexcessmaterialshallbetrimmed,removed,and

disposedof.Anylowareaswillbereplacedwiththesubsequentsurfacecourses.No

loosematerialshallbeleftinplaceaftertrimming.Aftertrimmingthestabilizedsubgrade

surfaceshallberolledagainwithasteelwheelorpneumatictiredrollertosealthe

surface.

8. Tolerances

a. Thickness-Stabilizedzonethicknessshallbeveriedbytheuseofphenolphthalein

andshallbeperformedatintervalsofapproximately500feetineachlane.When

themeasurementofthethicknessisdecientbymorethan1inchfromtheplan

thickness,twoadditionallocationsshallbemeasuredrandomlywithinthedecien

areaandusedindeterminingtheaveragethickness.Whentheaveragethickness

isdecientbymorethan1inch,theentireareashallbereprocessedtomeetthe

designparametersortheroadwaydesignsectionmustbere-evaluated.

b. Grade-Priortoplacementofsurfacecourse,anydeviationinexcessof1/2inchincross-sectionand1/2inchin10feetmeasuredlongitudinallyshallbecorrected.

Variationsinexcessofthistoleranceshallbecorrectedbythecontractor,atthe

contractorsexpense,inamannersatisfactorytoCityEngineering.Thickness

requirementsshallbemetinareascorrectedforgrade.


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Table 14 Schedule or Minimum Materials Sampling and Testing

(Chemically Stabilized Soils)

Test Type Test Standard Minimum Frequency o Tests

Sampling AASHTOT87 Oneper2,500squareyardsSamplePreparation ASTMD3551

MaximumDryDensityandOptimumMoistureContent

ASTMD698(Lime)ASTMD558(Cement)

MinimumofonepersoiltypeorasdirectedbyCityEngineering

InPlaceSoilDensityASTMD1556ASTMD2167ASTMD6938 Onetestforeach250lanefeet

(notlessthanonetestperday)InPlaceMoistureContent ASTMD2216ASTMD6938

Ph ASTMD6276 Onetestper2,500squareyards

SwellASTMD4546MethodB

Minimumonetestper2,500squareyardsorasdirectedbyCityofColoradoSprings,

UnconnedCompressiveStrength(Lime)

ASTMD5102(ProcedureB)Onesetoffourcylindersper2,500squareyards.

CompressiveStrengthCementitiousAgents

ASTMD1633(MethodA)Onesetoffourcylindersper2,500squareyards.

AtterbergLimits AASHTOT89&T90 Onetestper2,500squareyards

StabilizationThickness Asdirectedbytestingagency Onetestevery500feetperlane

6.6 Mechanically Stabilized Subgrade

Thisworkincludesmechanicallystabilizedsubgradeofbase/subbasecourseand/orsubgrade

improvementintheconstructionofpavedorunpavedroadways.Designdetailsforgeogrid

reinforcement,suchasgeogridtype,llthickness,pavementcross-sectionandassociated

details,shallbeasshownontheprojectdrawings.Purpose-Thepurposeoftheworkshallbeto

provideastabilizedpavingplatformsectiononwhichpavingmaterialscanbeplaced.Subgrade

stabilizationshallextendtothebackofcurbasaminimum.Thisitemshallnotbeusedtoretain

moistureinsubgradesunlessretainingmoistureinthesectioncanbeassured.Thisspecication

shallbeusedforaconstructionplatformandnotasameansofmitigatingswell.

1. Materials

a. Denitions

1. Mechanically Reinorced-Placementofageogridimmediatelyoverasoftsubgradesoilinordertoimprovethebearingcapacityandmitigatedeformationofthesubgradesoil.Thegoalofthisapplicationmaybetoreducedeeperexcavationrequirements,improveconstructioneciency,reducetheamountofaggregatesubbase/basematerialrequired,provideastiworkingplatformforpavementconstruction,orcombinationofthese.


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2. Geogrid -Abiaxialpolymericgridformedbyaregularnetworkofintegrallyconnectedtensileelementswithaperturesofsucientsizetoallowinterlockingwithsurroundingsoil,rock,orearthtofunctionprimarilyasreinforcement.

3. Multi-Layer Geogrid -Ageogridproductconsistingofmultiplelayersofgrid

whicharenotintegrallyconnectedthroughout.

4. Extruded GeogridAgeogridproductformedbyextrusionofapolypropyleneorpolypropylene/polyethylenecopolymersheetfollowedbyitsperforationwithaprecisearrangementofholesandsubsequentstretching,ordrawing,intothenishedproduct.

5. Woven GeogridAgeogridproductformedbyweavingdiscretestripsofpolymerintoanetwork.Thesegeogridsusuallyrequireaprotectivecoatingtoprotectthepolymerfrompre-maturedegradation.

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

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

8. Junction Strength-BreakingtensilestrengthofjunctionswhentestedinaccordancewithGRI-GG2asmodiedbyAASHTOStandardSpecicationforHighwayBridges,1997Interim,usingasingleribhavingthegreaterof3

junctionsoraminimum8inchmachinedirectionsampleandtestedatastrainrateof10percentperminutebasedonthisgaugelength,valuesshownareMARVs.Formulti-layergeogridproducts,junctionstrengthtestingshallbeperformedacrossjunctionsfromeachlayerofgridindividually,andresultsshallnotbeassumedasadditivefromsinglelayerstomultiplelayers.

9. Flexural Stiness(alsoknownasFlexuralRigidity)-ResistancetobendingforcemeasuredviaASTMD1388-96,OptionA,usingspecimendimensionsof864millimetersinlengthby1apertureinwidth,valuesshownareMARVs.Formulti-layergeogridproducts,exuralstinesstestingshallbeperformeddirectlyonthemulti-layercongurationwithoutusinganyconnectingelementsotherthanthoseusedcontinuouslythroughouttheactualproduct,andresultsshallnotbeassumedasadditivefromtestingperformedonasinglelayerofthemulti-layerproduct.

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


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11. Granular Fill Material Thepreferredgradationforbasereinforcementapplicationiswell-gradedcrushedaggregatellwithamaximumparticlesize(100percentpassing)of1inches,andlessthan10%nes(passingthe#200sieve).RecycledconcretemaybeusedonlywithpolypropylenegeogridsinaccordancewithFederalHighwayAdministration(FHWA)2001.

2. Manuacturers

a. Allmanufacturerswillbeconsideredprovidedtheymeetthesubmittalprocessas

perTable6.6.3.

3. Geogrid Material Properties

a. StructuralSoilReinforcementGeogridThegeogridshallbeintegrallyformedand

deployedasasinglelayerhavingthefollowingcharacteristicsaccordingtoTable

15(allvaluesareminimumaveragerollvaluesunlessarangeorcharacteristicis

indicated.)

b. Geotextilematerialsshallnotbeconsideredasanalternatetogeogridmaterialsfor

subgradeimprovementorbase/sub-basereinforcementapplications.Ageotextilemaybeusedinthecross-sectiontoprovideseparation,ltrationordrainage;

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/ARectangularorSquare

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

FlexuralRigidityASTMD1388-96Note2

Mg-cm 250,000 750,000

MinimumTensileStrength@2%Strain:

ASTMD6637-01Note4-MD3 Lb/ft 280 410

-CMD3

Lb/ft 450 620MinimumTensileStrength@5%Strain:

ASTMD6637-01Note4-MD3 Lb/ft 580 810

-CMD3 Lb/ft 920 1,340


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NOTES:

1. TheratioofJunctionStrength/UltimateTensileStrengthmustmeetorexceed75%.

2. ResistancetobendingforcemeasuredviaASTMD-5732-95,usingspecimensofwidthtworibswide,withtransverse

ribscutushwithexterioredgesoflongitudinalribs(asaladder),andoflengthsucientlylongtoenable

measurementoftheoverhangdimension.

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

4. TrueresistancetoelongationwheninitiallysubjectedtoaloaddeterminedinaccordancewithASTMD6637without

deformingtestmaterialsunderloadbeforemeasuringsuchresistanceoremployingsecantorosettangent

methodsofmeasurementsoastooverstatetensileproperties.

4. Construction Platorm Design

Constructionplatformdesignshallbeperformedundersupervisionofandsignedby

aProfessionalEngineerregisteredintheStateofColoradopracticingasageotechnical

engineer.TherecommendedprocedureshallbefollowedasoutlinedinAASHTOPP46-

01.Appropriatepartialsafetyfactorsshallbeappliedtoresultsobtainedusinggeogrids

havingpropertiesorcharacteristicsoutsidetherangeofrigorousmodelvalidation

(GiroudandHan,2004).ThismethodhasbeenendorsedbynumerousDepartmentofTransportationsandGovernmentAgenciessuchastheFederalHighwayAdministration

andArmyCorpsofEngineers.Apipingratioanalysis(D15ll/D85subgrade)shallbe

performedtodeterminetheneedofaseparationfabric.Ifthepipingratioislessthan5

thennoseparationfabricisrequired.Ifthepipingratioisgreaterthan5thenaseparation

fabricisrequiredbelowthegeogrid.Finaldeterminationofconstructionplatformshallbe

approvedbyCityEngineering.

5. Utility Cuts

Repairofutilitycutsingeogridmaterialshallbeaccomplishedpermanufacturer

specications.

6.7 Proo Rolling

TheSubgradeplatformshallbethoroughlyproof-rolledtothesatisfactionoftheCityInspector

priortoplacementofbasecourse(orpaving)andthebasecourseshallbethoroughlyproof-

rolledtothesatisfactionoftheCityinspectorpriortopaving.ReferenceSection205oftheCitys

StandardSpecications.

6.8 Water Testing

Assoonaspracticaluponnalpavementconstructionthenishedpavementsurfaceshallbe

water-testedtothesatisfactionoftheCityEngineeringinspectortoconrmpositivesurface

drainageinalldirectionspriortoacceptanceofthestreet.Watershallbeappliedusingawater

truckspraybarorsimilardeviceatarateadequatetodemonstratepositivedrainageowacross

thecrownandintothestreetgutters.

.


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7.0 Defnitions

AASHTO:AmericanAssociationofStateHighwayandTransportationOcials

Adhesive Failure:Lossofbondbetweenthejointsealantandthejoint,orbetweentheaggregateandthebinder.

Agency:Thejurisdictionorowneroftheprojectanditsrepresentatives.

Aggregate Base (base course):Crushedstoneorgravel,immediatelyunderthesurfacecourse.

Aggregate Interlock:Interactionofaggregateparticlesacrosscracksandjointstotransferload.

Alligator Cracks:Interconnectedcracksformingaseriesofsmallblocksresemblinganalligatorsskinorchickenwire.

Analysis Period:Theperiodoftimeforwhichtheeconomicanalysisistobemade;ordinarilywillincludeatleastonerehabilitationactivity.

Asphalt Emulsion Slurry Seal:Amixtureofemulsiedasphalt,neaggregateandmineralller,withwateraddedtoproduceslurryconsistency.Sealsareusedasapreventativemaintenancetreatmenttoprovideanewwearingsurfaceandtollsmallcracks.

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

Asphalt Overlay:Oneormorecoursesofasphaltconstructiononanexistingpavement.Theoverlaygenerallyincludesalevelingcourse,tocorrectthecontouroftheoldpavement,followedbyuniformcourseorcoursestoprovideneededthickness.

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

ASTM:AmericanSocietyforTestingMaterials

Binder:AsphaltCementusedtoholdstonestogetherforpaving.

Binder Course:Thelayerofasphaltcementconcretepavementunderlyingthesurface

course.

Bituminous:Likeorfromasphalt.

Bleeding or Flushing:Theupwardmovementofasphaltinanasphaltpavementresultingintheformationofalmonthepavementsurface.Itcreatesashiny,glass-like,reectivesurfacethatmaybetackytothetouchinwarmweather.

Block Cracking:Theoccurrenceofcracksthatdividetheasphaltsurfaceintoapproximatelyrectangularpieces,typicallyonesquarefootormoreinsize.


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

Centerline:Thepaintedlineseparatingopposingtraclanes.

Channels:Aditchorcanaladjacenttheroadway.

Chipping:Breakingorcuttingosmallpiecesfromthesurface.

Chip Seal:Athinlayerofemulsiedasphaltcementinwhichaggregateisembedded.Thesealisplacedtoimprovethetextureofthepavementsurfacetoincreaseskidresistanceanddecreasepermeabilityofthesurface.

City Street:Astreetwhosetracispredominantlylocalincharacter.

Cohesive Failure:Thelossofamaterialsabilitytobondtoitselforitssubstrate.Resultsinthematerialsplittingortearingapartfromitselforitssubstrate(i.e.jointsealantsplitting)

Composite Pavement:Apavementstructurecomposedofanasphaltcementconcrete

pavementwearingsurfaceoveraggregatebasecourseortreatedsubgrade.

Contractor:Thelanddeveloperoritsagentsinvolvedintheconstructionoftheproject.

Corrugations (Washboarding):Aformofplasticmovementtypiedbyripplesacrossthepavementsurface.Mostcommoninaggregatesurcialpavementsbutoccursinasphaltcementconcretepavementsaswell.

Crack:Approximatelyverticalrandomcleavageofthepavementduetothermalorloadaction.

Crack Seal:Anasphaltcementorsimilarmaterialappliedintoapavementcracktoprovideanon-permeableseal.Thesealantmusthaveadequatecharacteristicstoprovide

bondingtoeachsideofthecrack.

CTS:ChemicallyTreatedSubgrade

Deection:Theamountofdownwardverticalmovementofasurfaceduetotheapplicationofaloadtothesurface.

Rebound Deection:Theamountofverticalreboundofasurfacethatoccurswhenaloadisremovedfromthesurface.

Representative Rebound Deection:Themeanvalueofmeasuredrebounddeectionsinatestsectionplustwostandarddeviations,adjustedfortemperatureandmostcriticalperiodoftheyearforpavementperformance.

Residual Deection:Thedierencebetweenoriginalandnalelevationsofasurfaceresultingfromtheapplicationto,andremovalofoneormoreloadsfrom,thesurface.

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

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


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Flexible Pavement:Pavementstructuresgenerallyconsistingofasphaltcementconcretepavementsurfacingthatmaintainsintimatecontactwithanddistributesloadstothesubbaseorsubgradeanddependsuponaggregateinterlock,particlefriction,andcohesionforstability.

Flowable Backfll:Abackllmaterialcomposedofalow-strength,self-levelingconcretematerial,composedofvariouscombinationsofcementyash,aggregate,waterandchemicaladmixturesusedtoowintoareasrequiringbackllthatwillprovidedensityandstrengthwithoutcompaction.

Fog Seal:Athinlayerofemulsiedasphaltcementappliedtothepavementsurface.Thesealisplacedasapreventivetreatmenttorejuvenatetheasphaltconcretepavementbyimprovingexibilityandtodecreasethepermeabilityofthesurface.

Free Edge:Pavementborderthatisabletomovefreely.

Full-Depth Asphalt Pavement:ThetermFULL-DEPTH(registeredbytheAsphaltInstitutewiththeU.S.PatentOce)certiesthatthepavementisoneinwhichasphaltmixtures

areemployedforallcoursesabovethesubgradeorimprovedsubgrade.AFull-Depthasphaltpavementislaiddirectlyonthepreparedsubgrade.

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

Grade Depressions:Localizedlowareasoflimitedsizewhichmayormaynotbeaccompaniedbycracking.

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

Heavy Trucks:Twoaxle,six-tiretrucksorlarger.Pickup,panelandlightfour-tiretrucksare

notincluded.Truckswithheavy-duty,widebasetiresareincluded.

Hot Bituminous Pavement:SeeHotMixAsphalt

Hydroplaning:Thedangerousactionofavehiclebeingdrivenonapavementoverwhichalmofrainorotherwaterhasformed;onreachingacertainspeed,thevehiclestirestendtorideuponthewatersurfaceratherthanthepavement,drasticallyreducingthedriverscontrolofthevehicle.

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

Incentive/Disincentive Provision (or quality):Apayadjustmentschedulewhich

functionstomotivatethecontractortoprovideahighlevelofquality.(Apayadjustmentschedule,evenonewhichprovidesforpayincreases,isnotnecessarilyanincentive/disincentiveprovision,asindividualpayincreases/decreasesmaynotbeofsucientmagnitudetomotivatethecontractortowardhighquality).

Instability:Thelackofresistancetoforcestendingtocausemovementordistortionofapavementstructure.

Internal Vibration:Vibrationbymeansofvibratingunitslocatedwithinthespeciedthicknessofpavementsectionandaminimumdistanceaheadofthescreedequaltothepavementthickness.


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Lane Line:Boundarybetweentravellanes,usuallyapaintedstripe.

Lane-to-Shoulder Drop-o:Thedierenceinelevationbetweenthetraclaneandshoulder.

Lane-to-Shoulder Separation:Wideningofthejointbetweenthetraclaneandthe

shoulder.

Layer Coecient:Theempiricalrelationshipbetweenstructuralnumber(SN)andlayerthicknesswhichexpressestherelativeabilityofamaterialtofunctionasastructuralcomponentofthepavement.

Lime Stabilized Subgrade:Apreparedandmechanicallycompactedmixtureorlime,waterandsoilbelowthepavementsystem.

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

Lime-Fly Ash Stabilized Subgrade:Apreparedandmechanicallycompactedmixtureof

lime,yash,waterandsoilbelowthepavementsystem.

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

Longitudinal:Paralleltothecenterlineofthepavement.

Longitudinal Crack:Acrackthatfollowsacourseapproximatelyparalleltothecenterline.

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

Materials/Methods Specifcations:Specicationsthatdirectthecontractortousespeciedmaterialsindeniteproportionsandspecictypesofequipmentandmethodstoplacethematerial.

Method Specifcations:SeeMaterials/MethodsSpecications.

Moisture Stabilized Subgrade:Swellingsoilswhichhavebeenstabilizedtolowornilswellbyadditionofmoisture.

Moisture Treatment:Additionofmoistureat1to3percentabovestandardProctoroptimummoisturecontentandcompactionto95percentdensity.

Parametric Analysis:Astudyofasetofphysicalpropertieswhosevaluesdeterminethecharacteristicsorbehaviorofsomething;usedtoisolatethesignicanceofindividualvariables.

Patch:Anareawheretheexistingpavementhasbeenremovedandreplacedwithanewmaterial.

Patch Deterioration:Distressoccurringwithinapreviouslyrepairedarea.

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


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assurancespecicationstypicallyarestatisticallybasedspecicationsthatusemethodssuchasrandomsamplingandlot-by-lottesting,whichletthecontractorknowifhisoperationsareproducinganacceptableproduct.)

Quality Control:Thosequalityassuranceactionsandconsiderationsnecessarytoassessproductionandconstructionprocessessoastocontrolthelevelofqualitybeingproducedintheendproduct.Thisconceptofqualitycontrolincludessamplingandtestingtomonitortheprocessbutusuallydoesnotincludeacceptancesamplingandtesting.

Raveling:Thewearingawayofthepavementsurfacecausedbythedislodgingofaggregateparticles.

Recipe Specifcations:SeeMaterials/MethodsSpecications.

Reection Cracking:Cracksinasphaltoverlaysthatreectthecrackpatterninthepavementstructureunderneath.

Resilient Modulus Test:Ameasureofthemodulusofelasticityofroadbedsoilorotherpavementmaterial.

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

Roadbed:Thegradedportionofahighwaybetweentopandsideslopes,preparedasafoundationforthepavementstructureandshoulder.

Roadbed Material:Thematerialbelowthesubgradeincutsandembankmentsandinembankmentfoundations,extendingtosuchdepthasaectsthesupportofthepavementstructure.

Roadway:Allfacilitiesonwhichmotorvehiclesareintendedtotravelsuchassecondaryroads,interstatehighways,streetsandparkinglots.

Roadway Land Use:Aclassicationbasedontheuseoflandadjacentorservicedbythestreet.Theclassicationisusedtoseparatestreetsfordierentvolumeassumptions.

Roughometer:Asingle-wheeledtrailerinstrumentedtomeasuretheroughnessofapavementsurfaceinaccumulatedmillimeters(inches)permile.

Rubberized Asphalt Cement:Blendofasphaltcementandpre-vulcanizedrubber.

Rutting:Longitudinalsurfacedepressionsinthewheelpaths.

Selected Material:Asuitablenativematerialobtainedfromaspeciedsourcesuch

asaparticularroadwaycutorborrowarea,ofasuitablematerialhavingspeciedcharacteristicstobeusedforaspecicpurpose.

Serviceability:Theabilityattimeofobservationofapavementtoservetrac(autosandtrucks)whichusethefacility.

Shoving:Permanent,longitudinaldisplacementofalocalizedareaofthepavementsurfacecausedbytracpushingagainstthepavement.

Single Axle Load:Thetotalloadtransmittedbyallwheelsofasingleaxleextendingthefullwidthofthevehicle.


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Skid Hazard:Anyconditionthatmightcontributetomakingapavementslipperywhenwet.

Slippage Cracks:Cracks,sometimescrescent-shaped,thatpointinthedirectionofthethrustofwheelsonthepavementsurface.

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

Soil Cement Base:Ahardenedmaterialformedbycuringamechanicallycompactedintimatemixtureofpulverizedsoil,Portlandcementandwater,usedasalayerinapavementsystemtoreinforceandprotectthesubgradeorsubbase.

Stabilized Subgrade:Asubgradesoilthathasbeenalteredbyachemicalagenttomakesuitableforsubgradeconstructionandpavementsupport.

Standard Deviation:Theroot-mean-squareofthedeviationsaboutthearithmeticmean

ofasetofvalues.Statistically Based Specifcations:Specicationsbasedonrandomsampling,andinwhichpropertiesofthedesiredproductorconstructionaredescribedbyappropriatestatisticalparameters.

Structural Number (SN):Anindexnumberderivedfromananalysisoftrac,roadbedsoilconditions,andenvironmentwhichmaybeconvertedtothicknessofexiblepavementlayersthroughtheuseofsuitablelayercoecientsrelatedtothetypeofmaterialbeingusedineachlayerofthepavementstructure.

Subbase:Thelayerorlayersofspeciedorselectedmaterialofdesignedthicknessplacedonasubgradetosupportabasecourse.

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

Subgrade:Thesoilpreparedtosupportastructureofapavementsystem.Itisthefoundationforthepavementstructure.Thesubgradesoilsometimesiscalledbasementsoilorfoundationsoil.

Subgrade, Improved:Anycourseorcoursesofselectorimprovedmaterialbetweenthesubgradesoilandthepavementstructure.

Subgrade Resilient Modulus:Themodulusofthesubgradedeterminedbyrepeated

loadtriaxialcompressiontestsonsoilsamples.Itistheratiooftheamplitudeoftheacceptedaxialstresstotheamplitudeoftheresultantrecoverableaxialstrain.

Surace (Surace Course):Oneormorelayersofapavementstructuredesignedtoaccommodatethetracload,thetoplayerofwhichresistsskidding,tracabrasion,andthedisintegratingeectsofclimate.Thetoplayerofexiblepavementsissometimescalledthewearingcourse.

Surace Thickness (Suracing Thickness, Surace, Slab Thickness (Rigid)):Thethicknessofsurfacingmaterial,usuallyexpressedininches.


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Swell Potential:Thepercentofvolumechangedexpectedforasoilsamplewhenwettedasmeasuredthroughlaboratorytestsconductedusingrepresentativeoverburdenpressures.

Tandem Axle Load:Thetotalloadtransmittedtotheroadbytwoconsecutiveaxlesextendingacrossthefullwidthofthevehicle.

Thermal Cracking:Crackingoccurringinpavementmaterialintroducedwithinthematerialresultingfromachangeintemperature.

Trac Equivalence Factor:Anumericalfactorthatexpressestherelationshipofagivenaxleloadtoanotheraxleloadintermsoftheireectontheserviceabilityofapavementstructure.

Transverse Crack:Acrackthatfollowsacourseapproximatelyatrightanglestothecenterline.

Triple (Tridem) Axle Load:Thetotalloadtransmittedtotheroadbythreeconsecutive

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

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

Upheaval:Thelocalizedupwarddisplacementofapavementduetoswellingofthesubgradeorsomeportionofthepavementstructure.

USCS:UniedSoilClassicationSystem.

Washboarding:SeeCorrugations.

Water Bleeding:Seepageofwaterfromjointsorcracks.

Weathering:Thewearingawayofthepavementsurfacecausedbythelossofasphaltbinder.

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