论文2.docx
- 文档编号:10476410
- 上传时间:2023-05-26
- 格式:DOCX
- 页数:14
- 大小:25.23KB
论文2.docx
《论文2.docx》由会员分享,可在线阅读,更多相关《论文2.docx(14页珍藏版)》请在冰点文库上搜索。
论文2
英文部分:
出处:
Vo1.2lNo.3JournaloIWuhanUniversityofTechnolo~,一Mater.i.EdSept.2006
标题:
CharactersiticsofStress—strainCurveofHighStrengthSteelFiber
ReinforcedConcreteunderUniaxialTension
作者:
YANGMengHUANGChengkuiWANGJizhong
(StateKeyLaboratoryofCoastalandOfshoreEngineering,DepartmentofCivil,Engineering,
DalianUniversityofTechnology,Oalian116023,China)
正文:
Abstract:
Awholeof110specimensdividedinto22groupsweretestedwithvooingthevolumefractionof
steelfibersandthematrixstrengthofthesespecimens.Thestress-strainbehaviorsoffo~typesofsteelfiberrein—
forcedconcrete(SFRC)l~2deruniaxialtensionwerestudiedexperimentally.nthematrixstrengthandthefi—
bercontentincrease,thetensilestressandtensilestrainvarydiferentlyaccordingtothefibertype.Themecha—
nismsofreinforc~ng@ctfordiferenttypesoffiberwereanalyzedandthestress-strainclll't~ofthespecimenswere
plotted.SomeexperimentalfactorsforS~esSorstrainofSFRCweren.Atensiletongh,~sHlo~lasRe05
introducedtoevaluatethetoughnesscharactersofSFRCl~2deruniaxialtension.Moreover,the[ormalaofthe
tensilestress-straincll~ofSFRCwasregressed.Thetheoreticalc11"i~andtheexperimental0,well,which
canbeusedforreferencesinconstruction.
Keywords:
steelfiberreinforcedconcrete;highstrength;uniaxialtension;stress-strainc11"i~:
softencharacteristics
1Introduction
Thetensilepropertiesofconcretecanbeenhanced
substantiallybyincorporatinghighstrengthandsmalldi—
ametershortsteelfibers.whichlcadstothesteelfiberre—
inforcedconcrete(SFRC).InconventionalSFRC,the
steelfibercontentisusuallywithintherangeof0.2%一
2%byvolume.Atsuchalow6hercontent.thetensile
responseofSFRCwouldassuIneanonhardeningtype.
whichischaracterizedbythewideningofasinglecrack,
similartoanunreinforeedconcrete.econtributionof
tibersis印parentinthepost—crackingresponse,repre—
sentedbyanincreaseinpost—crackingductilityduetothe
workassociatedwithpulloutoffibersbridgingafailure
crack.However,improvementsinsomeotherproperties
areinsignificant.Moreover,thesofteningsegmentof
thestress—straincurveofSFRCthsuchalowfibercont—
entunderuniaxialtensionisdificulttobegotwithnormal
experimentalmethods.Manyworkshavebeendoneto
findasuitableandrelativelyeasywaytoanalyzetheten—
silecharacteristics。
。
.Anditwasreportedthatthewhole
curvecouldbegotonanormaltestingmachinewithstiif_
eningcomponentsadded
Inthisarticle,thestress—strainbehaviorofSFRC
underuniaxialtensionWasanalyzedfordifferenttypesof
fiber.ThetensilecharacteristicsofSFRCinflueneedby
thematrixstrengthandthesteelfibercontentwerestudied
also.Inaddition,thestress—straincurvesofhighstrength
SFRCwithdifferentfactorswerewellacquired.
(Received:
April17,2005;Accepted:
March6,2006)
YANGMeng(杨萌):
PhDcandidate;E-mail:
yangmeng@stu—
dent.dlut.edu.cn.
*FundedbyRegulationRevisingItemofChinaAssociationforEn—
gineeringCork~tmctionStandardization(CECS15:
2000)
2Experimental
Thespecimensweretestedona60kNuniversaltest—
ingmachine.Fourhighsteelbarswereaddedtoenhance
thestiffnessofthetestingmachine.Inaddition,spheric
hingeswereusedtoabatetheinitialaxialeeeentricityof
thespecimens..
Itwasensuredthatspecimensshouldbepulled1.113一
deruniaxialtensionbyaajustingthefourhighstrengthbo—
ltswhichconnectthespecimenstotheCroSSbeam.And
thedifferencebetweenthetensilestrainsoftheopposite
sidesofthespecimenshouldbelessthan15%oftheir
meanvalue.Whenthefibercontentwaslow(0and0.
5%byvolume),thecyclic
quirethewholestress—strain
2.1Materials
tensionwaywasusedtoae—
eun,e.
FourtypesofsteelfibersshowninTabk1werecho—
senforthistest.reeofthesefibers(F1,F2andF3)
werehooked—endandtheotherone(F4)wassmoth.
Threeconcretemixtures,showninTable2,werein—
vestigated.WaterreducingagentswereusedinC60and
C80mixes(DK一5madebyDalianStructureResearchIn—
stituteandSikamadeinSwitzerlandrespectively).e
compressivestrengthsoftheseC30,C60,C80mixeswere
determinedaccordingto“TestMethodsUsedforSteelFi—
berReinforcedConcrete”(CECS13:
89)"83at28days
using150Bin×150Bin×150Bincubes.Averagedre—
suitsfor3specimensaregiveninTable2.0rdinaryPort—
landcement(yieldedbyDalianHuanengOnodaCement
Company)of32.5and52.5(accordingtoChinastaB—
dard)werechosen.Riversand(modulusoffinenessis2.
6)andcrushedlimestonecoarseaggregates(5—20Bin)
wereused.
维普资讯
Vo1.21No.3YANGMeetfzf:
Stud。
nStress-strainCunP()fHighStrPl1州1SteelFill/eiI1tbrce~t....133
Note:
F忙r——nsijecrackstressofSFRC;f(.r——nsilecrackstressofplainconcretentheSalllemixproportion;fi~UhimatctensilestrengthofSFRC
——UfinlHfetensilestrengthofplainconcretewiththesanlemixingproportion.
2.2Spc~imem
Thetensilespecimenwasbondedtosteelpadding
platesatbothendsbytygoweld.Atotalof110specimens
weredividedinto22groupsaccordingtocertainparame—
ters.TheparametersofthesespecimensareshowninTa—
ble3.
2.3Items
Attheageof28days.plainconcreteandsteelfiber
concretespecimensweretestedfortensilestrength,
resqectively.Thetensilestress—straincurveswereac。
quired.Manyothertensilecharactersofthehighstrength
steelfiberconcretesuchastensilework,etcwerecalcu—
latedalso
3ResultsandDiscussion
3.1Crackstressandultimatetensilestrength
Thecrackstressandultimatetensilestrengthofdifferent
specimensarelistedinTable3.Theadditionof
steelfibersintoconcreteincreaseditscracks[ressandultimate
tensilestrength.AndtheratiosofthesetwoparaiTl~
etersofSFRCtothoseofplainconcreue(withthesame
mixproportion)aregiveninTable3,too.
3.1.1Effectofmatrixstrengthan(1fibertype
FH)mFable3.it(·anbeseenthattheeffectsofsteel
fibers0ncrackstressarelittleinfluencedbythematsix
strength.TI1atish)sav.whenthenlatr/xstrengthi11{7‘reas-
维普资讯
134JournalofWuhanUniversityofTechnology.
一Mater.Sei.EdSept.2006
es,theratiosofcrackstressesofSFRC(ththesame
typeoffiberscontained)tothoseofplaioconcreteones
withthesamemixproportionareinvariable.
However,theconditionforultimatetensilestrength
isdifferent.Whenthematrixstrengthincreases.thesera—
ticsofultimatetensilestrengths(showninTable3)vary
dissimilarlyaccordingtothetypeofsteelfiber.Moreover.
theincrementsarebiggerthanthoseofcrackstress.
TheheighteningefficiencyoffiberF1forultimate
tensilestrengthrisesasmatrixstrengthincreases.Itis
becausethatthestrengthofthiskindoffiberisveryhigh
(>1100MPa).Nofiberbrokenwasobservedduringthe
testandthehooked—endsofthefiberswerestraightened
whenthematrixstrengthwashigh(C80).Thehigherthe
matrixstrength.thiskindofsteelfibertakesonits
strengtheningeffectmoreeficientlyfortheincreasingof
bondstress.ThestrengthsoffibersF2andF3aremid—
high(>700MPa).Thevallhavebokedendsandboth
oftheirsurfacesarecoarse.enthematrixstrengthwas
high(C80).fiberbreakingoccurredinthetest.Andthis
phenomenonimpairedtheheighteningeficiencyofthese
twokindsofsteelfiber.Sotheyshouldbeusedinmiddle
strengthconcretetoexerttheirstrengtheningefectmore
eficiently.FiberF4issmooth.anditsbondstresswith
matrixiscomparativelylow.T}1erefore.itsstrengthening
effectis1essnotablethanthoseofotherkindsoffiber.
Becauseofthelowbondstress.nofiberbrokenwasfound
duringthetestanditsheighteningeficiencyforultimate
tensilestrengthrisesasmatrixstrengthincreases.
3.1.2Effectoffibercontent
Theeffectoffibercontentonthecrackstressandu1.
timatetensilestrengthwasinvestigatedforSFRCcon—
tainedfiberF3.Andthefibercontentvariedfrom0.5%
to1.5%byvolume(showninTable3).Itcanbeseen
fromFig.1andFig.2thatasthefibercontentincreases.
thecrackstressandultimatetensilestrengthofSFRCim.
proveobviously.Moreover.therisingtrendsofthecurves
inthesetwofiguresarestupendouslysimilar.Inother
words,theeffectoffibercontentonthecharactersoften.
silestressofSFRCispositiveandconsistent.
Table4Fjbertvaefactors
Fibercoded.
Fl
F2
F3
F4
O.642
O.862
0.794
0.589
ThetensilestrengthofSFRCcanbecalculatedwith
thefollowformula:
=×(1+a)
(1)
where,istheultimatetensilestrengthofsFRc;the
ultimatetensilestrengthofplainconcretewiththe
samemixingproportion;a,thefibertypefactor,
whichisSh。
Ⅵ1inTable4;,:
告,isIhe—
bercontent0fv。
l愀aI1d吾istheaspectrali。
0f
steelfibers
3.2Tensilestrainandtoue.hnesscharacters
3.2.1Crackstrainandthestrainatpeaktensilelcad
Thetensilestrainswel'~acquiredbyaveragingthe
readingsofthefourdisplacementsensorsfixedaroundthe
specimen.Inaddition,thespecimenswhosedifference
betweenthetensilestrainsofitsoppositesidesislarger
than15%oftheirmeanvaluewereblankedout.
Thecrackstrainorthestrainsatpeaktensilelcadof
SFRCaremuchbigerthanthoseofplainconcrete(as
showninTable5).Andtheincrementsgoupasthema—
trixstrengthorthefibercontentincreases.Comparedto
thatoncrackstrain.theincrescenteffectofsteelfiberon
thestrainatpeaktensilelcadismoreremarkable.
3.2.2Tensileworkandtoughnessmodulus
Thetensileworkwasdefinedastheareaunder
theload-displacementcurvefrom0to0.5rain.More—
over,atensile
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 论文