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ENGINEERING CRITERIA MANUAL
SECTION IIPavement Design
Criteria Manual
ENGINEERING 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
ENGINEERING CRITERIA MANUAL
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
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ENGINEERING CRITERIA MANUAL
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.
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ENGINEERING CRITERIA MANUAL
1.1 Design Report
TheDesignReportistoconsidertheconditionsafterdesignofthepavementalignmentandelevation,andafterthestreetiscuttoutilitygrade(utilitygrade,or“rough”grade,isdefinedaswithin+/-0.2’offinalgrade).Thenatureofsubgradesoilswhichexpandorcollapseduetowettingprovideuniquedesignproblemswhicharebestaddressedduringroughgradingoperations.APreliminaryGeotechnicalInvestigationofthestreetalignmentisappropriatewhenexpansiveorcollapsiblesoilconditionsarepresent,andwhenover-excavation,moisturetreatmentandre-compactionofthesubgradeduringmasssitegradingisexpectedtobeappropriate.Thepreliminaryinvestigationboringsmustbelocatedinbothcutandfillareas,andmustbeproperlysurveyedforbothhorizontalandverticallocation.BoringsmustextendbelowfinishsubgradeelevationsperboringdepthsasdiscussedinSection2.0.
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ENGINEERING CRITERIA MANUAL
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.
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ENGINEERING CRITERIA MANUAL
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.
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ENGINEERING CRITERIA MANUAL
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.
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ENGINEERING CRITERIA MANUAL
Thedesignsoilsupportvalueshallbedeterminedtobethelowestvalueobtainedfromthetesting.IntheeventtheDesignEngineerelectstoremoveandreplacethelowestsupportvaluetoaminimumdepthof2feetbelowfinishsubgrade,thesupportvalueofthereplacementfillcanbeused.Technicaljustification(calculations)fortheremovalandreplacementshallbeprovidedinthereport.
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ENGINEERING CRITERIA MANUAL
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.
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ENGINEERING CRITERIA MANUAL
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.
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ENGINEERING CRITERIA MANUAL
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:
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ENGINEERING CRITERIA MANUAL
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
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ENGINEERING CRITERIA MANUAL
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
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ENGINEERING CRITERIA MANUAL
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:
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ENGINEERING CRITERIA MANUAL
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.
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CityEngineeringreservestherighttomakethepavementtypeselectionusingtheseand/orothercriteriaonCityfundedprojects.
1Special Drainage Considerations: Thedesignengineershouldanticipatethefuturedevelopedconditionofthelandadjacenttotheroadwaywhenmakingthepavingdesignrecommendations.Evenwhennoshallowgroundwaterispresentinthepre-developedconditionitisexpectedthatcertainlandusessuchassinglefamilyhomesandprojectswithirrigatedlandscapingpresentthepossibilityofwaterenteringtheroadsubgradeandadverselyaffectingtheperformanceandlongevityofthepavement.Cityforceshavetoinstallretrofitunderdrainsystemsinmanystreetstomitigatethesekindsofproblems.AppropriaterecommendationsanddesignfeaturestostopwaterfrominfiltratingintothepavementsectionwillreceivepositiveresponsefromCityEngineering.
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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.
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- 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:
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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.
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Figure 1 Design chart for flexible pavements
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Figure 2 Design chart for rigid pavements Local & Collector
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Figure 3 Design chart for rigid pavements
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Figure 4 Design chart for rigid pavements
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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.
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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.
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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.
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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. b.Water-Waterusedformixingorcuringshouldbefromapotablesource.Intheeventpotablewaterisnotused,non-potablewatershallbetestedinaccordancewithandmeettherequirementsofAASHTOT26andusedinthemixdesign.
c. 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.
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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
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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:
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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.
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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
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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.
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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.
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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.
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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.
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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
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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.
.
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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.
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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.
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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.
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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.
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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.
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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
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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
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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.
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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.
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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.
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