土木工程外文翻译5.docx

土木工程外文翻译5.docx

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土木工程外文翻译5

附录

（一）外文原文

4.2.1.1CementTestbySieveNo.170

Thefinenessofcementaffectsthequalityoftheconcreteindustryingeneral.Abig

cementparticlecannotcompletelyreactwithwateraswatercannotreacharemaining

coreinthecementparticle.Thewaterpropagatesthroughthecementparticlesand

theystarttodehydrate,whichcausesanincreaseintemperature,whichisthemain

reasonfortheformingofhaircracksandpreventingstabilizationofcementvolume.

Asaresult,anincreaseinthecementparticlesizereducesthestrengthofthesame

cementcontentandincreasingthefinenessofthecementwillimprovetheworkability,

cohesion,anddurabilitywithtimeanddecreasethewatermovingupwardtothe

concretesurface.

Figure4.1,fromNeville’sbook（1983）,presentstherelationbetweenconcrete

strengthandtheconcretefinenessatdifferentages.Toperformthistest,takeasample

of50gofcementandshakeitinaclosedglassbottlefortwominutesandthen

revolvethesamplegentlyusingdrybar.Putthesampleinaclosedbottleandleave

itfortwominutes.Putthesamplein170sieve（90microns）andmoveit,shaking

thesievehorizontallyandrotationally,thenconfirmfinishingthesievetestwhenthe

rateofpassingcementparticlesisnotmorethan0.5g/minduringthesieveprocess.

Removethefinescarefullyfromthebottomofthesieveusingasmoothbrush.Then,

collectandweightheremainingparticlesonthesieve（W1）.

Repeatthesametestwithanothersample.Thentheresidualweightforthesecond

testisobtained（W2）.Calculatethevaluesoftheremainingsamplesthrough

R1=（W1/50）×100

R2=（W2/50）×100

Theratio（R）iscalculatedbytakingtheaverageofR1andR2tothenearest0.1%

and,inthecaseofdeviatingresultsofthetwosamples,morethan1%.Dothetesta

thirdtimeandtaketheaverageofthethreeresults.

Youcanacceptorrefusethecementbasedonthefollowingcondition:

ForPortlandcementt•heRmustnotexceedthan10%.

•ForrapidhardeningPortlandcementtheRmustnotexceed5%.

4.2.1.2InitialandFinalSettingTimesofCement

PasteUsingVicatApparatus

Theobjectiveofthistestistodefinethetimeforinitialandfinalsettingofthepaste

ofwaterandcementwithstandardconsistencybyusingaVicatapparatusanddetermine

whetherthecementisexpiredorcanbeused.

Theinitialsettingistherequiredtimetosetandafterthatconcretecannotbepoured

orformed;thefinalsettingtimeisthetimerequiredfortheconcretetobehardened.

Vicatapparatus（Figure4.2）consistsofacarrierwithneedleactingunderaprescribed

weight.Thepartsmoveverticallywithoutfrictionandarenotsubjecttoerosion

orcorrosion.Thepastemoldismadefromametalorhardrubberorplasticlike

acutconewithdepthof40±2mmandtheinternaldiameteroftheupperface70±

5mmandlowerface80±5mmandprovidesatemplateofglassorsimilarmaterials

inthesoftersurface.Itsdimensionsaregreaterthanthedimensionsofthemold.

Theneedleisusedtodeterminetheinitialsettingtimeinasteelcylinderwith

effectivelength50±1mmanddiameter1.13±0.5mm.Theneedlemeasuringtime

isintheformofacylinderwithlengthof30±1mmanddiameter1.13±0.5mmand

heldbya5mmdiameterringatthefreeendtoachievedistancebetweentheendof

theneedleandtheringof0.5mm.

Theteststartsbytakingasampleweighingabout400gandplacingitonan

impermeablesurfaceandthenadding100mlofwaterandrecordingzeromeasurement

fromthetimeofaddingwatertothecementandthenmixingfor240+5seconds

ontheimpermeablesurface.

Todeterminetheinitialsettingtimeandcalibratethedeviceuntiltheneedle

reachesthebaseofthemold,thenadjustthemeasuringdevicetozeroandreturn

needletoitsoriginalplace.

Fillthemoldwithcementpastewithstandardconsistencyandtrollthesurface,

thenputthemoldforashorttimeinaplacethathasthethetemperatureandhumidity

requiredforthetest.

SpecificSurface（Wagner）-m2/kg

365days

90days

28days

7days

20

150200250300

30

40

50

CompressiveStrength,Mpa

Transferthemoldtotheapparatusundertheneedle,andthenmaketheneedle

slowlyapproachthesurfaceuntilittouchesthepaste’ssurface,stopitinplacefor

asecondortwosecondstoavoidimpactofprimaryspeed,thenallowthemoving

partstoimplementtheneedleverticallyinthepaste.

Gradingdependsonwhentheneedlestopspenetratingorafter30seconds,whichever

isearlier,andindicatesthedistancebetweenthemoldbaseandtheendofthe

needle,aswellasthetimestartfromthezerolevelmeasurement.

Repeattheprocessofimmersingtheneedleinthesamepasteindifferentlocations

withthedistancebetweentheimmersingpointandtheedgeofthemoldor

betweentwoimmersingpointsnotless10mmafterabout10minutes,andcleanthe

needleimmediatelyaftereachtest.

Recordtimeismeasuredfromzeroupto5±1mmfromthebaseofthemoldas

theinitialsettingtimetothenearest5minutes.Ensuringtheaccuracyofmeasurement

oftimebetweentestsreducesembedmentandthefluctuationofsuccessive

tests.Theneedleisusedtoidentifythefinaltimeofsetting;followthesamesteps

asindeterminingtimeofinitialsettingandincreasetheperiodbetweenembedment

teststo30minutes.

Recordthetimefromzeromeasurementuntilembedmentoftheneedletoadistance

of0.5mm,whichwillbethefinalsettingtime.Controltheimpactofthe

needleonthesurfaceofthesamplesothefinalsettingtimepresentstheeffectof

theneedle.Toenhancethetest’saccuracyreducethetimebetweenembedmenttests

andexaminethefluctuationofthesesuccessivetests.Recordthefinalsettingtime

tothenearest5mm.

AccordingtotheEgyptianspecificationstheinitialsettingtimemustnotbeless

than45minutesforalltypesofcementexceptthelowheatcement,forwhichthe

initialsettingtimemustnotbeless60minutes.Thefinalsettingtimemustbeshorter

than10hoursforalltypesofcement.

4.2.1.3DensityofCement

Thepurposeofthistestistodeterminethedensityofcementbyidentifyingthe

weightandunitvolumeofthematerialbyusingtheLeChatelierdensitybottle.The

determinationofthecementdensityisessentialforconcretemixdesignandtocontrol

itsquality.ThistestfollowsspecificationsoftheAmericanSocietyforTesting

andMaterials,ASTMC188-84.

TheLeChatelierdeviceisastandardroundbottle.Itsshapeanddimensionsare

showninFigure4.3.Thisbottlemusthavealltherequireddimensions,lengths,and

uniformdegradationandaccuracy.

TheglassthatisusedintheLeChatelierbottlemustbeofhighqualityandfree

fromanydefects.Itshouldnotinteractwithchemicalsandhavehighresistanceto

heatandappropriatethicknesstohaveahighresistancetocrushing.Measurements

startatthebottle’sneckandgofromzeroto1mLandfrom18to24mLwithaccuracy

to0.1mL.Eachbottlemusthaveanumbertodistinguishitfromanyother.

Writeonthebottlethestandardtemperatureandthecapacityinmillimetersoverthe

highestpointofgrading.

Processedsamplecementweighingabout64gtothenearest0.05gmustbe

tested.

Fillthebottlewithkerosenefreefromwaterandoilwhosedensityisatleast62

API.Uptopointgradationsbetweenzeroand1mL,drytheinnersurfaceofthe

bottleatthehighestlevelofkeroseneifnecessary,anduserubberonthesurfaceof

thetableusedforthetestwhenfillingthebottle.

Thebottle,whichisfilledwithkerosene,isplacedinawaterbathandthefirst

readingtokerosenelevelisrecorded.Torecordthefirstreadingcorrectlyinstallthe

bottleinthewaterbathvertically.Putacementsampleweighing64gwithaccuracy

to0.05ginsidethebottlewithsmallbatchesatthesametemperatureofkerosene,

takingintoaccountwhenputtingthecementinsidethebottletoavoidcementdropping

outoritsadhesionontheinternalsurfacesofthebottleatthehighestlevel.The

bottlecanbeplacedonthevibratingmachinewhenputtingthecementinsidethe

bottletoexpeditetheprocessandpreventadhesionofgranulatedcementwiththe

internalsurfacesofthebottle.

Afterlayingthecementinsidethebottle,putacaponthebottlemouthandthen

spindiagonallyonthesurfacesoastoexpeltheairbetweenthegranulesofcement,

andcontinuemovingthebottleuntiltheemergenceofairbubblesstopsfromthe

kerosenesurfaceinsidethebottle.

Putthebottleinthewaterbathandthentakethefinalreading,andrecordthe

readingatthelowersurfaceofkerosenesoastoavoidtheimpactofsurfacetension.

Forthefirstandfinalreadings,makesurethatthebottleisplacedinawaterbath

withconstanttemperatureforaperiodnottoexceedthedifferenceintemperature

betweenthefirstandfinalreadingsofabout0.2°C.

Thedifferencebetweenthefirstandfinalreadingisthevolumeofthemoving

liquidbythecementsample.

Thevolumeofthemovingliquid=finalreading–firstreading

4.2.1.4DefineCementFinenessbyUsingBlaineApparatus

Thistestisusedtodeterminethesurfaceareabycomparingthetestsamplewiththe

specificreference.Thegreatersurfaceareaincreasesthespeedofconcretehardening

andobtainsearlystrength.Thistestdeterminestheacceptanceofthecement.

TherearemanyteststodefinecementfinenessandoneisaBlaineapparatusas

statedinmanycodessuchastheEgyptiancode.

Thistestdependsoncalculatingthesurfaceareabycomparingthesampletestand

thereferencesampleusingaBlaineapparatustodeterminethetimerequiredtopass

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