土木工程材料英文版

Civilengineeringmaterials郭亚龙122303304Abstract:Structuralengineeringdependsontheknowledgeofmaterialsandtheirproperties,inordertounderstandhowdifferentmaterialssupportandresistloads.Keyword:Iron:Wroughtiron,CastironConcrete:Reinforcedconcrete,PrestressedconcreteAlloy:Steel,StainlesssteelMasonryTimber:Hardwood,SoftwoodAluminiumCompositematerials:PlywoodOtherstructuralmaterials:Adobe,Bamboo,Carbonfibre,Fiberreinforcedplastic,Mudbrick,Roofingmaterials1.IronisachemicalelementwiththesymbolFeandatomicnumber26.Itisametalinthefirsttransitionseries.Itisthemostcommonelement(bymass)formingtheplanetEarthasawhole,formingmuchofEarth'souterandinnercore.ItisthefourthmostcommonelementintheEarth'scrust.Iron'sverycommonpresenceinrockyplanetslikeEarthisduetoitsabundantproductionasaresultoffusioninhigh-massstars,wheretheproductionofnickel-56(whichdecaystothemostcommonisotopeofiron)isthelastnuclearfusionreactionthatisexothermic.Thiscausesradioactivenickeltobecomethelastelementtobeproducedbeforecollapseofasupernovaleadstotheexplosiveeventsthatscatterthisprecursorradionuclideofironabundantlyintospace.Likeothergroup8elements,ironexistsinawiderangeofoxidationstates,−2to+6,although+2and+3arethemostcommon.Elementalironoccursinmeteoroidsandotherlowoxygenenvironments,butisreactivetooxygenandwater.Freshironsurfacesappearlustroussilvery-gray,butoxidizeinnormalairtogivehydratedironoxides,commonlyknownasrust.Unlikemanyothermetalswhichformpassivatingoxidelayers,ironoxidesoccupymorevolumethanironmetal,andthusironoxidesflakeoffandexposefreshsurfacesforcorrosion.Ironmetalhasbeenusedsinceancienttimes,thoughcopperalloys,whichhavelowermeltingtemperatures,wereusedfirstinhistory.Pureironissoft(softerthanaluminium),butisunobtainablebysmelting.Thematerialissignificantlyhardenedandstrengthenedbyimpurities,suchascarbon,fromthesmeltingprocess.Acertainproportionofcarbon(between0.002%and2.1%)producessteel,whichmaybeupto1000timesharderthanpureiron.Crudeironmetalisproducedinblastfurnaces,whereoreisreducedbycoketopigiron,whichhasahighcarboncontent.Furtherrefinementwithoxygenreducesthecarboncontenttothecorrectproportiontomakesteel.Steelsandlowcarbonironalloysalongwithothermetals(alloysteels)arebyfarthemostcommonmetalsinindustrialuse,duetotheirgreatrangeofdesirablepropertiesandtheabundanceofiron.Ironchemicalcompounds,whichincludeferrousandferriccompounds,havemanyuses.Ironoxidemixedwithaluminiumpowdercanbeignitedtocreateathermitereaction,usedinweldingandpurifyingores.Itformsbinarycompoundswiththehalogensandthechalcogens.Amongitsorganometalliccompoundsisferrocene,thefirstsandwichcompounddiscovered.Ironplaysanimportantroleinbiology,formingcomplexeswithmolecularoxygeninhemoglobinandmyoglobin;thesetwocompoundsarecommonoxygentransportproteinsinvertebrates.Ironisalsothemetalusedattheactivesiteofmanyimportantredoxenzymesdealingwithcellularrespirationandoxidationandreductioninplantsandanimals.2.Concreteisacompositematerialcomposedofcoarsegranularmaterial(theaggregateorfiller)embeddedinahardmatrixofmaterial(thecementorbinder)thatfillsthespaceamongtheaggregateparticlesandgluesthemtogether.Concreteiswidelyusedformakingarchitecturalstructures,foundations,brick/blockwalls,pavements,bridges/overpasses,highways,runways,parkingstructures,dams,pools/reservoirs,pipes,footingsforgates,fencesandpolesandevenboats.FamousconcretestructuresincludetheHooverDam,thePanamaCanalandtheRomanPantheon.ConcretetechnologywasknownbytheancientRomansandwaswidelyusedintheRomanEmpire—theColosseumwasbuiltlargelyofconcreteandtheconcretedomeofthePantheonistheworld'slargest.AftertheEmpirewasdestroyed,useofconcretebecamescarceuntilthetechnologywasre-pioneeredinthemid-18thcentury.3.Alloyisamixtureorsolidsolutioncomposedofametalandanotherelement.Analloycontainsoneormoreofthethree:asolidsolutionoftheelements(asinglephase);amixtureofmetallicphases(twoormoresolutions);anintermetalliccompoundwithnodistinctboundarybetweenthephases.Solidsolutionalloysgiveasinglesolidphasemicrostructure,whilepartialsolutionsexhibittwoormorephasesthatmayormaynotbehomogeneousindistribution,dependingonthethermal(heattreatment)historyofthematerial.Aninter-metalliccompoundhasoneotheralloyorpuremetalembeddedwithinanotherpuremetal.Alloysareusedinsomeapplications,wheretheirpropertiesaresuperiortothoseofthepurecomponentelementsforagivenapplication.Examplesofalloysaresolder,brass,pewter,phosphorbronzeandanamalgam.Thealloyconstituentsareusuallymeasuredbymass.Alloysareusuallyclassifiedassubstitutionalorinterstitialalloys,dependingontheatomicarrangementthatformsthealloy.Theycanbefurtherclassifiedashomogeneous(consistingofasinglephase),orheterogeneous(consistingoftwoormorephases)orintermetallic(wherethereisnodistinctboundarybetweenphases).4.Masonryisthebuildingofstructuresfromindividualunitslaidinandboundtogetherbymortar;thetermmasonrycanalsorefertotheunitsthemselves.Thecommonmaterialsofmasonryconstructionarebrick,stone,marble,granite,travertine,limestone,caststone,concreteblock,glassblock,stucco,tile,andcob.Masonryisgenerallyahighlydurabl