专业英语论文.docx

专业英语论文.docx

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专业英语论文

Lownoiseasphaltpavement

By***

experimentclassofCivilengineering

Keywords:

lownoise;Asphaltpavement;Mix;Mixdesign

Abstract:

Inordertostudylownoiseasphaltpavementmixturegradationdesignmethod,usingtheaggregategradationdesignandoptimumasphaltcontentaslownoiseasphaltpavementmixdesigntwomajordesignindex,adoptthetokenmethodtodetermineaggregategradationdesign,bythemeansofthetheoreticalcalculation,flowtestandasphaltdroptestanalysis,todeterminetheasphalt.Thebestmixtureasphaltcontent.Theresultsshowthatthetokenmethodgetmixturevoidsandtargetvoidratiohasagoodlinearcorrelation,theflowtestmethodtodeterminetheoptimumasphaltcontentofasphaltmixture,moreaccordswiththepracticeofengineeringandeasytogeneralize.Lownoiseasphaltmixtureduetodifferentfromordinaryasphaltmixture,socan'tuseordinaryasphaltmixturedesignmethodtostudy.Asphaltmixdesign,includingaggregategradationdesignandoptimumasphaltcontentdeterminetwocontent,andInChinathereisnomatureexperience.Thedesignmethod,itisthestudyofthemainproblemsneedtobesolved.

Introduction:

Inrecenttenyears,thankstothegovernmentincreasedthetransportationinfrastructureconstructionforceandactiveinvestmentpolicy,China'srapiddevelopmentofhighwayconstruction,especiallythemainnationalhighwayconstructionhasmadegreatprogress,roadnetworkisthetotalsizeandoveralltechnicallevelhaveincreasedgreatly.Bytheendof2000,thenationalhighwaymileageunderstanding167.980000kilometers,ofwhichgradehighway131.590000kilometers,

Thenationalroadnetworkdensityupto17.5km/hundredsquarekilometers.Therapiddevelopmentofhighwayconstruction,increasetransportcapacity,promoteregionaleconomicrapiddevelopmentspeed,butalsotothesurroundingenvironmentcausedbyacertaindegreeofpollutiondamage,trafficnoiseisoneofthemajorpollution.

Trafficnoiseasakindofnoisepollution,theresidentsoftheinterferenceinmanycountrieshasmorethanotherformsofnoisepollution.

InFrance,80%ofthosesurveyedthinknoisepollutionindailylifethebiggestcauseofinterference,halfofwhichpeoplethinkthattrafficnoiseisthemainnoisesource.Similarly,inBeijingasurveyalsoshowedthatthetrafficnoisepollutioncomplaintsaccountedformorethan55%ofthetotalnoisecomplaints.Thetrafficnoisepollutioneconomiclossisdifficulttoaccuratelymeasure,in1996theEuropeancommission,saysareportfromtheEuropeanUnioncountrieshomeeveryyearbecauseofthelosscausedbytrafficnoiseestimatesofGDP0.2%~2%.

InChina,withtherapiddevelopmentofnationaleconomy,theappearanceofalargenumberofnewpassengerandcargotrafficvolume,thedomesticvariousoperatingvehiclesandprivatecarsocietyhasdoubledto1990asanexampleis632.980000quantity,to1999increaseto1986.820000quantity.Theamountofcarnumbermultiplied,plustheroadmileageincrease,levelenhancementandtheimprovementoftheroads,certainlywillbringroadtrafficofrapidgrowth,ifnottakeeffectivemeasures,willcausethedeteriorationoftheroadnoisepollution.Inurbanroadtrafficnoiseasanexample,accordingtotheChinaenvironmentalconditionsbulletinofthedata,theurbanroadtrafficnoisepollutionin2000comparedwith1999showsascendanttrend,table1-1isthenational200keycitytrafficnoiselevel.

Table1-1in1999and2000,nationalkeyurbantrafficnoisemonitoringresultscomparison

year\pollutionlevel

Heavypollution（%）

Moderatepollution（%）

Lightpollution

（%）

Good

（%）

1999

5.2

8.5

27.3

59

2000

8.9

22.4

53.3

15.4

Ingeneralspeaking,thekeyurbanroadtrafficnoisepollutioninmildbasicstate,individualmainlinebothsidesevenoverweightstrictheavy.Beijing'sfourthringroad（highwaystandard）asanexample,2001yearsofnoisetestresultsshowthattheaveragenoisebetweendayfor74.3~77.6dB（A）between,nightfor73.8~77dB（A）between.Muchmorethannationalstandarddayroom70dB（A）,night55dB（A）betweenthehighestlimit.

Sourcetodistantspread,acousticenergywithdiffusiondistanceincreases;decayrateandtheshapeofthewavefront.However,ifthereisasourceclosetothesurface,itwouldhappen,andthenthesurfaceofthesoundwavereflectionappearadditionalsounddiffusion.Thiskindofadditionalsounddiffusioneffectintheautomobiletirenoisediffusionprocessisveryoutstanding.Whenclosetothesourceofthereflectingsurfaceisporousstructure,additionalsounddiffusioneffectwilloccurinthetablesurface.Atthistime,thedistancetoreceivethesoundpressurelevelisdirectdiffusionacousticandreflectionofthesoundwavesuperpositioneffect.Whentheacousticconstitutethemainpartofthephasedifferencefor180degreesoccurswhenthedestructionofthesoundwaveinterference,syntheticpressuredecline.Tirenoiseinthereflectionsurfacediffusion,damageinterferenceoccurredinhighfrequencysoundwavespart.Thisisbecausethetirenoisesourceclosetothesurface（usuallylessthanroad5cm）,soundwavesandacousticreflectionofthephasedifferenceissmall,damageinterferencewillonlybepossibleinsmallwavelengthacoustic（i.e.,morethan8000Hertzhighfrequencynoise）.However,tirenoiseinporesurfacediffusionpropagation,duetotheadditionalphasechange,damageinlowfrequencyinterference（generalfor800~1000hz）acousticpartoccurred.Andthispartofthesoundwaveisthetirenoiseisthemaincomponentofenergy.Inaddition,theporeofthepavementstructurealsocanabsorbpartofthetirenoise.Comprehensivetheabovediscusses,cartirenoisesourcemainlyincludestwokindsofworkingmechanism:

1）tireandroadsurfaceincontactclosedair"compressionandsuckout";2）roadtablebumpmaketiresproducevibration.Tirenoiseisspreadinthereflectionofsoundwavessuperpositionanddamagemechanismofinterference,etc.

Designofthebasicconditions

Functionalprerequisite

Lownoiseasphaltpavement,withotherpavementtypedifferences,itshasasoundabsorptionpropertyandwaterpermeabilityandotherspecialfunctions.Inaddition,theuseofmixinadditiontoshouldhaveaspecifictargetfunctionoutside,stillhavetomeettherequirementsofthedurability,whichmeansthefunctionalityanddurability,andatthesametimedependsonthegapmixture,soinordertoensurefunctionalityanddurabilityaretoreachtherequiredstandard,mustbecarefullyselectedmixingofvoids.

Theasphaltamount,mixtureofvoidfractionandthefunctionalanddurablesexrelationmodelasshowninfigure1shows.Fromthechartthatthevoidfractionandthefunctionalanddurablesexrelationshipisinstead,buttherearebothsatisfiedrange.Inthemixfitthandesign,firstmakesurethecommonvoidsrangeisveryimportant,notemeaningcommonrangebythelowerlimitoffunctional,limitthedurabilityofthedecision.Aboutfunctionsex,mainlyisthesoundabsorptionpropertiesandwaterpermeability,etc.;Durability,basicallybethedeformationresistanceandabrasionperformanceandmechanicalproperties.

Practicalnecessaryconditions

Lownoiseasphaltmixture,withordinaryasphaltmixturephasecomparison,inresistancetopeelresistanceanddurabilityisbad,whichrequiresthevoidsinthemeetfunctionalandresistancetolongsexatthesametime,otherperformanceshouldnothavepracticalproblems.

Inordertogetpracticalmixture,controltheamountofasphaltaddhowmuch,isveryimportant.Inthepermittedgapraterangeanddonotproducewrappingcoveringbadandflushphenomenonatthesametime,tomixappliedforces,getasmuchaspossibletoensurethestabilityoftheaggregatequalitativebetweencohesiveforce.Inthiswaytheaddingamountofdecisionasphaltisquitenecessary.

Asphaltquantitytobeadded,voidratioandtherelationshipbetweenthecohesiveforcebetweenaggregate,asshowninfigure2shows.WhentheamountofasphaltintheA1,asphalt,aggregatewrappedbythecompletelybetweenbondingforceextremelow.Withtheincreaseofaddingamountofasphalt,asphalt,aggregatewrappedoverlyingbecomegoodbetweencohesiveforceisgettinghigher,butasmallervoids,whenachievedinA2,duetotheasphaltsurplus,togenerateflushphenomenonatthesametime,theaggregatebetweencohesiveforceisalsoconstantlydecreaseuntildoesn'tworksofar.

Thusitcanbeseen,lownoiseasphaltmixtureasphaltinadditionquantity,itisgraphphysicallinerepresentsA1-A2range.Butinordertoensurethestabilityofthemixture,itisnecessarytosetthataggregateitcanimprovethecohesiveforcebetweentheasphaltaddingamountofA3.Therefore,itisconsideredthattheaddingamountofasphaltinA3-A2range,cangetpracticalmixturecharacter.Thelowerlimitoftheaggregatebetweencohesiveforce,andupperlimitoftheproduceflushnowliketodeterminethethresholdquantity.Itisconcludedthatinlownoisedesignofasphaltmixture,thefirstsetmustbesetatthesametimesatisfythefunctionalanddurabilityofthevoidfraction,andthendeterminecanguaranteethevoidageofaggregategradation,andpresstheaggregategradationdeterminetheaddingamountofasphalt.

Designmethod

externalfactorsset

Tomixwiththedesign,inadditiontointernalfactorsshouldbeconsideredmixtureoutside,alsowanttoconsidertheuseplaceweatherconditions,trafficandroadwidth,etc.Casessuchascoldsnowareaandhopetogetabrasionresistanceroadarea,itisnecessarytoconsiderreducegaporusehighcohesiveforceoftheasphalt.Inadd