毕业论文外文翻译-公路的路面

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1、PavementHighwaypavementsaredividedintotwomaincategories:rigitandflexible.ThewearingsurfaceofarigidpavementisusuallyconstructedofPortlandcementconcretesuchthatitactslikeabeamoveranyirregularitiesintheunderlyingsupportingmaterial.Thewearingsurfaceofflexiblepavements

2、,ontheotherhand,isusuallyconstructedofbituminousmaterialsuchthattheyremainincontactwiththeunderlyingmaterialevenwhenminorirregularitiesoccur.Flexiblepavementsusuallyconsistofabituminoussurfaceunderlaidwithalayerofgranularmaterialandalayerofasuitablemixtureofcoarse

3、andfinematerials.CoarseaggregatesFineaggregatesTrafficloadsaretransferredbythewearingsurfacetotheunderlyingsupportingmaterialsthroughtheinterlockingofaggregates,thefrictionaleffectofthegranularmaterials,andthecohesionofthefinematerials.Flexiblepavementsarefurtherd

4、ividedintothreesubgroups:hightype,intermediatetype,andlowtype.High-typepavementshavewearingsurfacesthatadequatelysupporttheexpectedtrafficloadwithoutvisibledistressduetofatigueandarenotsusceptibletoweatherconditions.Intermediate-typepavementshavewearingsurfacestha

5、trangefromsurfacetreatedtothosewithqualitiesjustbelowthatofhigh-typepavements.Low-typepavementsareusedmainlyforlow-costroadsandhavewearingsurfacesthatrangefromuntreatedtoloosenaturalmaterialstosurface-treatedearth.®Thecomponentsofaflexiblepavementincludethesubgrad

6、eorpreparedroadbed,thesubbase,basecourse,andthesurfacecourse(Fig.11.1).®UppersurfacecourseMiddlesurfacecourseLowersurfacecourseTheperformanceofthepavementdependsonthesatisfactoryperformanceofeachcomponent,whichrequiresproperevaluationofthepropertiesofeachcomponent

7、separately.®Thesubgradeisusuallythenaturalmateriallocatedalongthehorizontalalignmentofthepavementandservesasthefoundationofthepavementstructure.®Thesubgrademayalsoconsistofalayerofselectedborrowmaterials,wellcompactedtoprescribedspecifications.®CompactingplantComp

8、actiondeviceCompactnessItmaybenecessarytotreatthesubgradematerialtoachievecertainstrengthpropertiesrequiredforthetypeofpavementbeingconstructed.—18—Loca