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ID:39990616
大小:866.04 KB
页数:20页
时间:2019-07-16
《Topic 5 - Material Characterization》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、Topic5–MaterialCharacterizationDr.ChristosDrakosUniversityofFloridaTopic5–MaterialCharacterization1.IntroductionPavementdesigninputscoveredinprevioustopics:•Predictedstressesandstrains–loadmagnitude•Traffic–loadcyclesWhatmaterialpropertieshaveweuseduptonow?•Mostpavingmaterialsarenotelastic,butexperi
2、encesomepermanentdeformationaftereachloadapplication•Iftheloadissmallcomparedtothestrengthofthematerialandisrepeatedforalargenumberoftimes,thedeformationisalmostrecoverableandcanbeconsideredelasticTopic5–MaterialCharacterizationResilientModulus(MR)Typeanddurationofloadingissupposedtosimulatethatoccu
3、rringinthefieldLoadTimeεrσdM=RDeformationεεrpTimeTopic5–MaterialCharacterizationTypicalFlexiblePavementStructureACDecreasingBASECOURSEStiffnessSUBBASECOURSE(Optional)SUBGRADE(SOIL)1.SurfaceCourse•Layerthatcomestocontactwithtraffic;normallycontainsthehighestqualitymaterial2.Base•Providesadditionalloa
4、ddistributionandcontributestodrainageandfrostresistance3.Subbase(optional)•Functionsprimarilyasstructuralsupportbutitcanalsohelpwithdrainageandfrostaction4.Subgrade•Nativesoil–theonlynon-engineeredmaterialinthepvtstructureTopic5–MaterialCharacterizationSubgradeperformancegenerallydependson:1.Loadbea
5、ringcapacity;subgrademustbeabletosupportloadspassedonfromthepavementstructure2.Moisturecontent;ittendstoaffectanumberofsubgradepropertiesincludingloadbearingcapacity3.Shrinkageand/orswelling;somesoilsshrinkorswelldependingupontheirmoisturecontentRemediesforpoorsubgradeconditions:1.Removeandreplace;s
6、ubgradesoilcanberemovedandreplacedwithhigherqualityfill2.Stabilization;addinganappropriatebinder–suchaslime,portlandcementoremulsifiedasphalt–canincreasesubgradestiffnessand/orreduceswellingtendencies3.Additionalbaselayers;includeasubbase,orincreasethicknessofbaseTopic5–MaterialCharacterizationSubgr
7、adeSeasonalVariationsMR50,000psiFrozenMRNormalMRThawMRFreezeThawRecoveryNormalTimeTimeTimeTimeTimeTotalTime=12MonthsTopic5–MaterialCharacterization2.DesignResilientModulus(Base&Subgrade)2.1Correlation
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