AfricasApproachtoSealsKJJXiamenDec2011

SOUTHAFRICA’SAPPROACHSOUTHAFRICA’SAPPROACHTOSURFACINGSEALSTOSURFACINGSEALSKimJ.JenkinsKimJ.Jenkins55ththInternationalPavementMaintenanceInternationalPavementMaintenanceTechnologyCongress:Xiamen,ChinaTechnologyCongress:Xiamen,China11ststto2to2ndndDecember2011December2011tellenboschOverviewOverview••WhentousesealsWhentouseseals••PurposeofsealsPurposeofseals••SealTypesSealTypes••SealSelectionConsiderationsSealSelectionConsiderationsTRAFFICDISTRIBUTIONPROCLAIMEDSURFACEDRURALROADS(SouthAfrica)020004000600080001000012000140000-200200-500500-10001000-20002000-40004000-60006000-1000010000-2000020000-5000050000-100000100000VEHICLESPERDAY(bothdirections)kmAsphaltSealsGravelBecarefulof%heavies15%GradedCostQualityofServiceTrackGravelSurfacedHighwaySurfacedStandardsEngineeredGravelBRIDGINGTHEQUALITYGAPAdditivesEngineeredSurfacedLVSRGuidelineWhypavedLVRs?WhypavedLVRs?PavedShoulderPavedShoulderZoneofSeasonalVariationZoneofSeasonalVariationMCXXSINGLESEALDOUBLESEALCAPESEALTypicalsealtypesusedinSouthAfrica(1)DOUBLESEALGEOTEXTILESEALSPLITSEALCHOKEDSEALINVERTEDD/SEALTypicalsealsusedinSouthAfrica(2)SealApplicationsSealApplications••InitialInitialseal(LVRstoExpressways)seal(LVRstoExpressways)••ResealReseal••Temporaryseale.g.deviationTemporaryseale.g.deviation••DustsuppressionDustsuppression••HoldingactionHoldingaction••LabourLabourintensiveconstructionintensiveconstruction…selectionofappropriatesealtypesInitialSurfacingInitialSurfacing••Acceptablenoiselevel(landuse,speed,Acceptablenoiselevel(landuse,speed,texture,voids)texture,voids)••Acceptableskidlevel(Risk,trafficvolume,Acceptableskidlevel(Risk,trafficvolume,geometry,rainfall,speed,macroµgeometry,rainfall,speed,macroµtexture)texture)••Wetweathervisibility(spray)Wetweathervisibility(spray)••Ridingquality(levelofservice)Ridingquality(levelofservice)••Inconveniencetoroadusers(Time,safety)Inconveniencetoroadusers(Time,safety)••RequiredperformanceRequiredperformance••Constructionmethod(Constructionmethod(labourlabourintensive?)intensive?)…requirementsInitialInitialSurfacingSurfacing••Basetypeandquality/sensitivityBasetypeandquality/sensitivity••TrafficTraffic((volumevolume,,type,type,actionsactions,,accommodation)accommodation)••GradientGradient(shoving,erosion)(shoving,erosion)••MaintenancecapabilityMaintenancecapability••EnvironmentalconditionsEnvironmentalconditions••Funds/Cost(materialavailability)Funds/Cost(materialavailability)••AbilityofcontractorsAbilityofcontractors…constraints…selectionofappropriatesealtypesBaselayerBaselayerTrafficconsiderationsTrafficconsiderations••HighervolumesHighervolumes––morevoidsrequiredmorevoidsrequired––MacrotextureMacrotexture••Governedbydesign&potentialGovernedbydesign&potentialembedmentembedment••LimitationsLimitations––modifiedbinders,asphaltmodifiedbinders,asphalt••HighlyvariabletrafficforLVRsHighlyvariabletrafficforLVRs––Agriculture:SeasonalAgriculture:Seasonal––Industrial:ForestryandminingIndustrial:Forestryandmining––Overloading:VerylittleenforcementOverloading:VerylittleenforcementRoadfunctionandRoadfunctionandclassificationclassificationPercentageVehicleswithatleastOneAxlePercentageVehicleswithatleastOneAxleexceedingLegalLimit(=100kNexceedingLegalLimit(=100kN»»22kips)22kips)0102030405060708090100120140160180200220ALLAGRICULT.CONSTR.TIMBERMolenaarTrafficCountDurationTrafficCountDurationvsvsErrorinADTErrorinADTTrafficActionsTrafficActions••Turning/BrakingTurning/Braking––SandSand––DoubleDouble––CapeCape––Asphalt/EpoxyAsphalt/Epoxy––––BlocksBlocks––ConcreteConcrete…selectionofappropriatesealtypesSpeedProfileSpeedProfile…selectionofappropriatesealtypes0102030405060AVGSPEEDOFHEAVIES(km/h)0100200300400500600700DISTANCE(m)WestboundEastboundBleedingstartsBleedingstartsaveragespeedofheavies(km/h)BleedingstartsBleedingstartsGradientGradient••ShovingShoving––Braking,curvesBraking,curves––ThicknessThickness––BasetypeBasetype••ErosionErosion––Kerbs?Kerbs?••ConstructabilityConstructability…selectionofappropriatesealtypesThickness&baseconditionThickness&basecondition…selectionofappropriatesealtypes…selectionofappropriatesealtypes…selectionofappropriatesealtypesSunninghillSunninghillHoughtonHoughtonHowDidThisHappen?MaintenanceCapabilityMaintenanceCapability-4-202468101214JanFebMarAprMayJunJulAugSeptOctNovDecDegC7yearminAve7yminEnvironment:Environment:MinMinTemperatureTemperature…selectionofappropriatesealtypesENGINEERINGOUTENGINEERINGOUT--OFOF--THEBOXSOLUTIONSTHEBOXSOLUTIONS7yearMinAirTemp(ºC)MonthSinglesealSingleseal--aggregatelossduetoearlytraffickingaggregatelossduetoearlytraffickingandcold,wetweatherandcold,wetweatherEnviroEnviroandSocialNeedsandSocialNeeds…selectionofappropriatesealtypesSocialNeedsSocialNeeds…selectionofappropriatesealtypesRidingQualityRidingQuality…selectionofappropriatesealtypesSkidResistance:SkidResistance:TextureTextureDepthDepth…selectionofappropriatesealtypesSingleseal+stonelossSingleseal+stoneloss…selectionofappropriatesealtypesCapeSealCapeSeal…selectionofappropriatesealtypesExamplesofCommonlyExampleso