道路工程(路橋)瀝青混合料的應(yīng)用理論和原則大學(xué)畢業(yè)論文外文文獻(xiàn)翻譯及原文

畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯文獻(xiàn)、資料中文題目：瀝青混合料的應(yīng)用、理論和原則文獻(xiàn)、資料英文題目： 文獻(xiàn)、資料來(lái)源： 文獻(xiàn)、資料發(fā)表（出版）日期： 院（部）:專業(yè)： 班級(jí)： 姓名： 學(xué)號(hào)： 指導(dǎo)教師：翻譯日期：2017.02.14外文文獻(xiàn)翻譯原文:AsphaltMixtures-Applications,TheoryandPrinciples.ApplicationsAsphaltmaterialsfindwideusageintheconstructionindustry.Theuseofasphaltasacementingagentinpavementsisthemostcommonofitsapplications,however,andtheonethatwillbeconsideredhere.Asphaltproductsareusedtoproduceflexiblepavementsforhighwaysandairports.Theterm“xible”isusedtodistinguishthesepavementsfromthosemadewithPortlandcement,whichareclassifiedasrigidpavements,thatis,havingbeamstrength.Thisdistinctionisimportantbecauseitprovidestheykeytothedesignapproachwhichmustbeusedforsuccessfulflexiblepavementstructures.Theflexiblepavementclassificationmaybefurtherbrokendownintohighandlowtypes,thetypeusuallydependingonwhetherasolidorliquidasphaltproductisused.Thelowtypesofpavementaremadewiththecutback,oremulsion‘liquidproductsandareverywidelyusedthroughoutthiscountry.Descriptiveterminologyhasbeendevelopedinvarioussectionsofthecountrytotheextentthatonepavementtypemayhaveseveralnames.However,thegeneralprocessfollowedinconstructionissimilarformostl ow-typepavementsandcanbedescribedasoneinwhichtheaggregateandtheasphaltproductareusuallyappliedtotheroadbedseparatelyandtheremixedorallowedtomix,formingthepavement.Thehightypeofasphaltpavementsismadewithasphaltcementsofsomesel ectedpenetrationgrade.Fig.?Amodernasphaltconcretehighway.Shoulderstripingisusedasasafelyfeature.Fig.?AsphaltconcreteattheSanFranciscoInternationalAirport.Theyareusedwhenhighwheelloadsandhighvolumesoftrafficoccurandare,therefore,oftendesignedforaparticularinstallation..TheoryofasphaltconcretemixdesignHightypesofflexiblepavementareconstructedbycombininganasphaltcement,ofteninthepenetrationgradeof85to100,withaggregatesthatareusuallydividedintothreegroups,basedonsize.Thethreegroupsarecoarseaggregates,fineaggregates,andmineralfiller.Thesewillbediscussedindetailinlaterchapter.Eachoftheconstituentpartsmentionedhasaparticularfunctionintheasphaltmixture,andmixproportioningordesignistheprocessofensuringthatnofunctionisneglected.Beforetheseindividualfunctionsareexamined,however,thecriteriaforpavementsuccessandfailureshouldbeconsideredsothatdesignobjectivescanbeestablished.Asuccessfulflexiblepavementmusthaveseveralparticularproperties.First,itmustbestable,thatistoresistanttopermanentdisplacementunderload.Deformationofanasphaltpavementcanoccurinthreeways,twounsatisfactoryandonedesirable.Plasticdeformationofapavementfailureandwhichistobeavoidedifpossible.Compressivedeformationofthepavementresultsinadimensionalchangeinthepavement,andwiththischangecomealossofresiliencyandusuallyadegreeofroughness.Thisdeformationislessseriousthantheonejustdescribed,butit,too,leadstopavementfailure.Thedesirabletypeofdeformationisanelasticone,whichactuallyisbeneficialtoflexiblepavementsandisnecessarytotheirlonglife.Thepavementshouldbedurableandshouldofferprotectiontothesubgrade.Asphaltcementisnotimpervioustotheeffectsofweathering,andsothedesignmustminimizeweathersusceptibility.Adurablepavementthatdoesnotcrackorravelwillprobablyalsoprotecttheroadbed.Itmustberememberedthatflexiblepavementstransmitloadstothesubgradewithoutsignificantbridgingaction,andsoadryfirmbaseisabsolutelyessential.Rapidlymovingvehiclesdependonthetire-pavementfrictionfactorforcontrolandsafety.Thetextureofthepavementsurfacesmustbesuchthatanadequateskidresistaneeisdevelopedorunsafeconditionsresult.Thedesignprocedureshouldbeusedtoselecttheasphaltmaterialandaggregatescombinationwhichprovidesaskidresistantroadway.Designprocedureswhichyieldpavingmixturesembodyingallthesepropertiesarenotavailable.Soundpavementsareconstructedwherematerialsandmethodsareselectedbyusingtime-testedtestsandspecificationsandengineeringjudgmentsal ongwithaso-calleddesignmethod.Thefinalrequirementforanypavementisoneofeconomy.Economy,again,cannotbemeasureddirectly,sincetrueeconomyonlybeginswithconstructioncostandisnotfullydeterminableuntilthefullusefullifeofthepavementhasbeenrecorded.If,however,therequirementsforastable,durable,andsafepavementaremetwithareasonablesafetyfactor,thenthebestinterestsofeconomyhaveprobablybeenservedaswell.Withtheserequirementsinmind,thefunctionsoftheconstituentpartscanbeexaminedwithconsiderationgivetohoweachpartcontributestonow-establishedobjectivesorrequirements.Thefunctionsoftheaggregatesistocarrytheloadimposedonthepavement,andthisisaccomplishedbyfrictionalresistaneeandinterl ockingbetweentheindividualpiecesofaggregates.Thecarryingcapacityoftheasphaltpavementis,then,relatedtothesurfacetexture(particularlythatofthefineaggregate)andthedensity,or “compatheaggregates.Surfacetexturevarieswithdifferentaggregates,andwhilearoughsurfacetextureisdesired,thismaynotbeavailableinsomelocalities.Densemixturesareobtainedbyusingaggregatesthatareeithernaturallyorartificially ed”.Thismearns/WhOtheadheaggregateservestofillthevoidsinthecoarseraggregates.Inadditiontoaffectingdensityandthereforestrengthcharacteristics,thegradingalsoinfluencesworkability.Whenanexcessofcoarseaggregateisused,themixbecomesharshandhardtowork.Whenanexcessofmineralfillerisused,themixesbecomegummyanddifficulttomanage.Theasphaltcementintheflexiblepavementisusedtobindtheaggregateparticlestogetherandtowaterproofthepavements.Obtainingtheproperasphaltcontentisextremelyimportantandbearsasignificantinflueneeonalltheitemsmarkingasuccessfulpavement.Achiefobjectiveofallthedesignmethodswhichhavebeendevelopedistoarriveatthebestasphaltcontentforaparticularcombinationofaggregates..Mixdesignprincipl esCertainfundamentalprinciplesunderliethedesignproceduresthathavebeendeveloped.Beforetheseprocedurescanbeproperlystudiedorapplied,someconsid erationoftheseprinciplesisnecessary.Asphaltpavementsarecomposedofaggregates,asphaltcement,andvoids.Consideringtheaggregatealone,allthespacebetweenparticlesisvoidspace.Thevolumeofaggregatevoidsdependsongradingandcanvarywidely.Whentheasphaltcementisadded,aportionoftheseaggregatevoidsisfilledandafinalair-voidvolumeisretained.Theretentionofthisair-voidvolumeisveryimportanttothecharacteristicsofthemixture.Thetermair-voidvolumeisused,sincethesevoidsareweightlessandareusuallyexpressedasapercentageofthetotalvolumeofthecompactedmixture.Anasphaltpavementcarriestheappliedloadbyparticlefrictionandinterlock.Iftheparticlesarepushedapartforanyreason,thenthepavementstabilityisd estroyed.Thisfactorindicatesthatcertainlynomoreasphaltshouldbeaddedthantheaggregatevoidscanreadilyhold.However,asphaltcementissusceptibletovolumechangeandthepavementissubjecttofurthercompactionunderuse.Ifthepavementhasnoairvoidswhenplaced,orifitlosesthemundertraffic,thentheexpandingasphaltwilloverfl owinaconditionknownasbleeding.ThelossofasphaltcementthroughbleedingweakensthepavementandalsoCoarseandlineaggregateAsphollcemenlandveryfineaggregateAi(voidsooceFig.?3Crosssectionofanasphaltconcretepavementshowingtheaggregateframeworkboundtogetherbyasphaltcement.Theneedforaminimumair-voidvolume(usually2or3percent)hasbeenestablished.Inaddition,amaximumair-voidvolumeof5to7percentshouldnotbeexceed.Anexcessofairvoidspromotesravelingofthepavementandalsopermitswatertoenterandspeedupthedeterioratingprocesses.Also,inthepreseneeofexcessairtheasphaltcementhardensandageswithanaccompanyinglossofdurabilityandresiliency.Theair-voidvolumeofthemixisdeterminedbythedegreeofcompactionaswellasbytheasphaltcontent.Foragivenasphaltcontent,alightlycompactedmixwillhavealargevoidsvolumeandalowerdensityandagreaterstrengthwillresult.Inthelaboratory,thecompactioniscontrolledbyusingaspecifiedhammerandregulatingthenumberofbl owsandtheenergyperblow.Inthefield,thecompactionandtheairvoidsaremoredifficulttocontrolandtestsmustbemadenospecimenstakenfromthecompactedpavementtocheekonthedegreeofcompactionbeingobtained.Trafficfurthercompactthepavement,andallowaneemustbemadeforthisinthedesign.Asystematiccheckingofthepavementoveranextendedperiodisneededtogivenfactualinformationforaparticularmix.Achangeindensityofseveralpercentisnotunusual,however.Asphaltcontenthasbeendiscussedinconnectionwithvariousfacetsoftheixdesignproblem.Itisaveryimportantfactorinthemixdesignandhasabearinganallthecharacteristicsldasuccessfulpavement:stability,skidresistanee,durability,andeconomy.Ashasbeenmentioned,thevariousdesignproceduresareintendedtoprovideameansforselectingtheasphaltcontent.Thesetestswillbeconsid eredindetailinafuturechapter,but

therelationshipbetweenasphaltcontentandthemeasurablepropertiesofstability,unitweight,andairvoidswillbediscussedhere.Asphaltctxilenl,percentAsphaltconlenl,percen!AsphaltcontendperctnlFig.4Variationsinstability,unitweight,andair-voidcontentwithasphaltcementcontent.Ifthegradationandtypeofaggregate,thedegreeofcompaction,andthetypeofasphaltcementarecontrolled,thenthestrengthvariesinapredictablemanner.Thestrengthwillincreaseuptosomeoptimumasphaltcontentandthendecreasewithfurtheradditions.Thepatternofstrengthvariationwillbedifferentwhentheothermixfactorsarechanged,andsoonlyatypicalpatterncanbepredictedpriortoactualtesting.Unitweightvariesinthesamemannerasstrengthwhenallothervariablearecontrolled.Itwillreachsomepeakvalueatanasphaltcontentnearthatdeterminedfromthestrengthcurveandthenfalloffwithfurtheradditions.Asalreadymentioned,theair-voidvolumewillvarywithasphaltcontent.However,themannerofvariationisdifferentinthatincreasedasphaltcontentwilldecreaseair-voidvolumetosomeminimumvaluewhichisapproachedasymptotically.Withstillgreateradditionsofasphaltmaterialtheparticlesofaggregateareonlypushedapartandnochangeoccursinair-voidvolume.Insummary,certainprinciplesinvolvingaggregategradation,air-voidvolume,asph