土木工程道路与桥梁方向 毕业设计翻译.docx

土木工程道路与桥梁方向 毕业设计翻译.docx

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土木工程道路与桥梁方向毕业设计翻译

Thereportshallcontain:

•typeofthetestingmachine

•specimenidentification

•testspecimendimensions

•curingconditionsandageattesting

•rateofdeformation

•load-deformationcurveincludingflexuralstressvaluesforthespecifieddeformation

classdeflections

•deformationclassandresidualstrengthclass

10.4Energyabsorptionclass（platetest）

Atestplateof600x600x100mmshallbesupportedonits4edgesandacentrepointload

appliedthroughacontactsurfaceof100x100mm（Figure10.4.1）.Theroughsideshallbeonthe

bottomduringthetest,i.e.theloadisappliedoppositetothesprayingdirection.

Therateofdeformationofthemidpointshallbe1.5mmperminute.

Figure10.4.1:

Set-Upforplatetest

Theplateshallbeproducedfromasprayedpanelbylevellingthepanelatathicknessof100mm-

0/+10mm,immediatelyafterspraying.Theslopededgesofthepanelshallbesawnoffwhenthe

plateispreparedinthelaboratory.Thepreparedplateshallbestoredinwaterforaminimumof3

daysimmediatelybeforetestingandkeptmoistduringtesting.

Theload-deformationcurve（Figure10.4.2）shallberecordedandthetestshallcontinueuntila

deflectionof25mmisachievedatthecentrepointoftheslab.

Fromtheload-deformationcurveasecondcurveshallbedrawngivingtheabsorbedenergyasa

functionoftheslabdeformation（Figure10.4.3）.

Thetoughnessrequirementsaregivenasaspecifiedenergyabsorptionatacertaindeflection.

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Figure10.4.2:

Exampleofload-deformationcurves

Figure10.4.3:

Exampleofenergy-deformationcurves

Thereportshallcontain:

•typeandstiffnessofthetestingmachine

•specimenidentification

•testspecimendimensions

•curingconditionsandageattesting

•rateofdeformation

•calculatedenergy-deformationcurves

•firstcrackloadandmaximumload

•calculatedenergy-deformationcurves

•energyabsorptioninJouleforadeflectionuntil25mm

10.5Modulusofelasticity

ThetestingshallbedoneinaccordancewithEN6784.

Thereportshallcontain:

•specimenidentification

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•testspecimendimensions

•curingconditionsandageattesting

•rateofdeformation

•load-deformationcurveincludingmaximumload

•estimatedmodulusofelasticity

10.6Bondstrength

Thebondstrengthshallbedeterminedbyapartialcoretest（whereappropriateinaccordancewith

EN1542）oratensiletest,thetestingarrangementbeingsimilartothoseshowninFigure10.6.1.

Therateofloadingshallbewithin1.0-3.0MPaperminute.Thecorediametershallbewithinthe

range50to60mm.Precautionsshallbetakentoensurethatthetensileforceisappliedaxially.

Thereportshallcontain:

•specimenidentification

•specimendimension

•ageattestingandcuringconditions

•rateofloading

•max.loadandcalculatedbondstrength

•descriptionoffailureplaneandmode

Fig.10.6.1:

Examplesofcorepullanddirecttensiontestingarrangementsforbondstrength

10.7Permeability

ThetestingshallbedoneinaccordancewithEN7031.

10.8Frostresistance

ThetestingshallbedoneinaccordancewithASTMC672orSS137244forscalingresistanceand

ASTMC666forfreeze-thawresistance.

10.9Determinationofthefibrecontentofsprayedconcrete

Thefibrecontentofsprayedconcretecanbedeterminedfromeitherfreshorhardened（i.e.before

orafterset）mortar/concretesamples.Bothtypesofsampleareapplicablewithsteelfibres,but

onlythemethodforafreshsampleisappropriatewithsyntheticfibres.

Freshsamplesmaybeextractedfromthebasicmix,theinsitumaterialorfromatestpanel.

Hardenedsamplesmaybecutfromtheinsitumaterialorfromatestpanel.Itshouldbe

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appreciatedthatthefibrecontentateachoftheselocationsmaybedifferent,duetothespraying

process.Themostappropriatesampletypeandlocationshouldbeused,whichwilldependon

thepurposeofthequalitycontrolandonthecompliancerequirementsofthespecification.

Forhardenedsamplesthetestmaybeconductedinas-received,saturatedoroven-driedmoisture

states.

Thevolumeofthesample（beforefibreextraction）canbedeterminedbycalculation（usingactual

dimensions）orbywaterdisplacement（referencemethod）.Themassofthefibreisthen

determinedbyweighing,followingextractionofthefibresfromthefreshorhardenedsample.

10.9.1Hardenedsample（MethodA）

Threetestcoresshallbecutfromtheinsitumaterialoratestpanel.Thecorediameter

shallbe75-150mmandthecorelengthshallbe75-150mm（unlessthelayerthicknessis

lessthan75mm,inwhichcasethecorelengthshouldequalthelayerthickness）.

Thevolume（Vc）ofthecoresshallbedeterminedaccordingbycalculation（usingactual

dimensions）orweighinginairandwater（methodgiveninEN6275）.

Theconcretecoresshallbecrushedinacompressiontestingmachine,orothersuitable

device,sothatallthefibresineachcorecanbeseparatedfromtheconcrete.Magnetic

fibrescanbeeasilyremovedbyamagnet.Thefibresfromeachcoreshallbecleanedand

thenweighed（mf）to0.1g.

10.9.2Freshsample（MethodB）

Threesamplesshallbecutfromtheinsitumaterialoratestpanel.Thesamplesshall

weigh1-2kgandmustbecarefullyextractedinonepiece.

Thevolume（Vc）ofthesamplesshallbedeterminedbyweighinginairandwater（method

giveninEN6275）.

Wash-outthefibrefromeachsprayedsample;thesprayedconcreteshallbeplacedina

filterequipmentwherethecementandotherfinematerialscanbewashedoutsuchthatthe

fibrecanbeseparatedfromthemass.Withsyntheticfibresthesamplesmaybesoaked

withalcoholandstirreduntilthefibresfloatonthesurface.Thefibresshallbecleaned,

driedandthenweighed（mf）to0.1g.

10.9.3Calculationoffibrecontent

Thefibrecontentofeachsampleshallbecalculatedfromthedeterminedfibremassand

samplevolume,usingtheformula:

Cf（kg/m³）=mfx1000/Vc

whereCfisthefibrecontent（inkg/m³）

mfisthemassoffibreextractedfromthesample（ing）

Vcisthevolumeofthesamplein（cm³）

Thereportshallcontain:

•specimenidentification（includinglocationofsampleandtimeofspraying）

•specimentype（hardenedorfresh）,sizesandvolumes

•dateandtimeoftesting

•descriptionoffibretype

•calculatedfibrecontentofeachsampleandthemeanvalueofthethreesamples

11.QUALITYCONTROL

11.1General

Theproductionofsprayedconcreteshallbesubjecttoqualitycontrolprocedures.Qualitycontrol

isdefinedasacombinationofactionsanddecisionstakenincompliancewithspecificationsand

checkstoensurethatthespecifiedrequirementsaresatisfied.

Thereare3classesofcontrol:

IMinorcontrol

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IINormalcontrol

IIIExtendedcontrol

Thechoiceofcontrolclassshallbeatthediscussionofthedesigner,basedontypeofproject

andconsequenceoffailure.

TherearenospecialrequirementsfortheorganisationoftheworkincontrolclassesIandII.In

controlclassIIIthereshallbeaorganigramforeachprojectwithaqualityassuranceengineer,

dedicatedtoqualitycontrol.

11.2Preconstructiontests

Compositionofthesprayedconcreteisdeterminedinthecourseofpreconstructiontestsinwhich

therequiredpropertiesarechecked.Examplesofpropertiestobechecked:

Freshconcrete:

•waterdemand,workability,pumpability,

•sprayability/rebound

•slump,density

•dosageofaccelerator

Hardenedconcrete:

•compressivestrengthat7and28days

•flexuralstrength

•residualstrength

•fibrecontent

•bond

Theneedforsuchtestsisdependentonthetypeofprojectandtheutilisationofthesprayed

concrete,butshouldalwaysbedoneincontrolclassIII.

11.3Qualitycontrol

11.3.1Undergroundsupport

Therearetwotypesofcontroltobespecified:

•Productioncontrol

•Conformitycontrol

TheproductioncontrolshallbeinaccordancewithEN206.Theconformitycontrolincludes

controlof:

•compressivestrength

•flexuralstrength

•residualstrengthvalue

•residualstrength

•energyabsorption

•bond

•fibrecontent

•thickness

Alltestsaretobedoneonsamplestakeneitherfromin-situmaterialortestpanels

accordingtoSection10.1.

Thefrequencyofthetestsshallbedecidedbythedesigner,bearinginmindthefunctionof

thesprayedconcrete（includingstructuralintegrity）,itsdesignlife,thedifficultyof

installation,theenvironmentalclassificationandtheconsequencesofafailure.Thevalues

giveninTable11.3.1maybeusedasaguide.

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Table11.3.1:

Frequencyofcontroltesting

TYPEOFCONTROLMINORNORMALEXTENDED

Compressivestrength500250100

Flexuralstrength500250

Residualstrengthvalue1000500

Energyabsorption1000500

Bond500250

Fibrecontent250100

Thickness502510

m²betweentests

11.3.2Alignmentcontrol

Alignmentcontrolisnecessarytoestablishlineandgradeinsprayedconcreteconstruction

andtoensurethatproperanduniformmaterialthicknessandcoveraremaintained.

Alignmentcontrolisaccomplishedbytheuseofguidewires,guidestrips,depthgages,

depthprobes,orconventionalforms.

Guidewires-Guidewiresconsistof1or0.8mmhighstrengthsteelwirecombinedwitha

device,usuallyaturn-buckleorspringcoil,thatplacesthewireundersuitabletension.

Theyarethemostconvenientmeanstoestablishlineandgradewhereformsareusedfor

backuppurposes.Wiresmaybeusedindividuallytoestablishcornerswhileseveralparallel

wiresincombinationmaybespaced0,6to0,9maparttoprovidescreedguidesforflat

areas.

Guidestrips-Guidestripsconsistofwoodlathusuallynolargerthan25x50mmconnected

bycrosspiecesat0.6to0.9mintervals.Guidestr