外文翻译低热硅酸盐水泥混凝土的抗裂性能

1、外文翻译Anti-CrackPerformanceofLow-HeatPortlandCementConcreteAbstract:Thepropertiesoflow-heatPortlandcementconcrete(LHC)werestudiedindetail.TheexperimentalresultsshowthattheLHCconcretehascharacteristicsofahigherphysicalmechanicalbehavior,deformationanddurability.Comparedwithmoderate-heatPortlandcement(M

2、HC),theaveragehydrationheatofLHCconcreteisreducedbyabout17.5%,Undersamemixingproportion,theadiabatictemperatureriseofLHCconcretewasreducedby2-3,andthelimitstensionofLHCconcretewasincreasedby10 x1O6-15x1O-6thanthatofMHC.Moreover,itisindicatedthatLHCconcretehasabetteranti-crackbehaviorthanMHCconcrete.

3、Keywords:low-heatportlandcement;massconcrete;highcrackresistance;moderate-heatportlandcementIntroductionTheinvestigationoncrackofmassconcreteisahotproblemtowhichattentionhasbeenpaidforalongtime.Thecracksoftheconcreteareformedbymulti-factors,buttheyaremainlycausedbythermaldisplacementsinmassconcrete1

4、131.Sothekeytechnologyonmassconcreteishowtoreducethermaldisplacementsandenhancethecrackresistanceofconcrete.Aswellknown,thehydrationheatofbondingmaterialsisthemainreasonthatresultsinthetemperaturedifferencebetweenoutsideandinsideofmassconcrete101.Inordertoreducetheinnertemperatureofhydroelectricconc

5、rete,severalmethodshavebeenproposedinmixproportiondesign.Theseincludeusingmoderate-heatportlandcement(MHC),reducingthecontentofcement,andincreasingthePortlandcement(OPC),MHChasadvantagessuchaslowheatofhydration,highgrowthrateoflong-termstrength,etc6J.SoitismorereasonabletouseMHCinapplicationofmassco

6、ncrete.Low-heatportlandcement(LHC),namelyhighbelitecementiscurrentlyattractingagreatdealofinterestworldwide.ThisislargelyduetoitslowerenergyconsumptionandCO2emissioninmanufacturethanconventionalPortlandcements.LHChasalotofnoticeableproperties,suchaslowheatofhydrationexcellentdurability,etc.sothefurt

7、herstudycontinuestobeimportant18-101.Thelong-termstrengthofC2ScanapproachtoorevenexceedthatofC3S1111.Inaddition,C2shasaseriesofcharacteristicssuperiortoC3s.TheseincludethelowcontentofCaO,lowhydrationheat,goodtoughness,compacthydrationproducts,excellentresistancestochemicalcorrosion,littledryshrinkag

8、e,etcl2A3.Forhydroelectricconcrete,thedesignrequirementshavesomecharacteristics,suchaslongdesignage,lowdesignstrength,lowhydrationtemperaturerise,andlowtemperaturegradient1141.AlltheserequirementsagreewiththecharacteristicsofLHC.Furthermore,LHChasahighhydrationactivityatlaterages,theeffectofwhichcan

9、improvetheinnermicro-crack.Basedonabove-mentionedanalyses,thepropertiesoflow-heatPortlandcementconcretewerestudiedindetailinthispaper.Comparedwiththemoderate-heatPortlandcement(MHC)concrete,theanti-crackbehaviorofLHCconcretewasanalyzed.ExperimentalMHCwasproducedinGezhoubaHoldingCompanyCementPlant,Ch

10、ina;andLHCwasproducedinHunanShimenSpecialCementCo.Ltd.,China.ThechemicalcompositionsandmineralcompositionsofcementarelistedinTable1andTable2respectively,andthephysicalandmechanicalpropertiesofcementarelistedinTable3.Inspiteofalittledifferenceinchemicalcompositions,thereisanobviousdissimilaritybetwee

11、nthemineralcomponentofLHCandthatofMHCbecauseofthedifferentburningschedule.TheC3s(Alite)contentofMHCishigherthanthatofLHC,andtheC2s(Belite)contentofLHCishigherthanthatofMHC.Aliteisformedattemperaturesofabout1450,whileBeliteisformedataround1200.Therefore,LHCcanbemanufacturedatlowerkilntemperaturesthan

12、MHC.AndtheamountofenergytheoreticallyrequiredtomanufactureLHCislowerthanthatofMHC.Belitehydratescomparativelyslowly,andtheearlycompressivestrengthsofpastes,mortars,andconcretescontainingLHCaregenerallylowerasaresult.Thelong-termstrengthanddurabilityofconcretemadefromLHCcanpotentiallyexceedthoseofMHC

13、.TheresultsfromTable3showthattheearlystrengthofLHCpastesislowerthanthatofMHCpastes,andthatthestrengthgrowthrateofLHCishigherthanthatofMHC.Thehydrationheatofbondingmaterialswastested.ClassIflyashofbondingmaterialscamefromShandongZhouxianPowerPlant,China.TheexperimentalresultsshowninTable4indicatethat

14、thehydrationheatofLHCismuchlowerthanthatofMHC.The1-day,3-dayand7-dayhydrationheatofLHCwithoutflyashis143kJ/kg,205kJ/kg,227kJ/kg,re叩ectively.The1-day,3-dayand7-dayhydrationheatofMHCwithoutflyashis179kJ/kg,239kJ/kg,278kJ/kg,respectively.ComparedwithMHC,theaveragehydrationheatofLHCconcreteisreducedbyab

15、out17.5%,Obviously,lowhydrationisofadvantagetoabatethepressuretotemperaturecontrol,andtoreducethecrackprobabilityduetothetemperaturegradients.TheadiabatictemperatureofLHCconcreteandMHCconcretewastested.Asaresult,theadiabatictemperatureriseofLHCconcreteislowerthanthatofMHCconcreteandthedifferentvalue

16、rangesfrom2to3ingeneral.Afteraddingflyash,allspecimensshowalowerhydrationheat,anditdecreaseswithincreasingflyashcontent.ForMHCwith30%flyash,the1d,3d,7daccumulativehydrationheatisreducedby14.5%,20.5%,21.9%,respectively;andforLHCwith30%flyash,the1d,3d,7daccumulativehydrationheatisreducedby21.7%,26.3%,

17、23.3%,respectively.Obviously,theeffectofflyashonthehydrationheatofLHCismorethanthatofMHC.ItiswellknownthattheflyashactivationcouldbeactivatedbyCa(OH)2.LHChasalowercontentofC3sandahighercontentofC2sthanMHC,sotheCa(OH)2,namelytheexcitercontentinhydrationproductsofLHCpastesislower.Decreasingthehydratio

18、nactivationofflyashreducesthehydrationheatofbondingmaterials.Table1Chemicalcompositionsofcementj,%labl2MineralcomponcnHofccmcnt/%CementSiO,AI,O,Ec.O,Cat)MgOSO.CementC,SC.AC.AFMHC22,864.214.6264.084.041.790.26MHC51.3526.R33.3214.04I.HC22.234.655.765H.634.533.260.35LHC21.022.5917.51Tabic3Physicalandni

19、cvhanicalpropeniourccmcntCcmcMSpecificsurface7(ma/kg)areaSellingin)InitialFinalStabili?Comperescivestrength/MPa3d7d28dFlexuralitrength/MPa3d1AMHC2:364:41Passed30.149.49.3LHC4092:464;5IPassed13.721.37.5ResultsandDiscussionInthisexperiment,ZB-1AtyperetardingsuperplasticizerandDH9ai

20、r-entrainingagentwereused.ThedosageofZB-1was0.7%bytheweightoftheblending,andthedosageofDH9wasadjustedtogiveanair-containingof4.5%to6.0%.Theparametersthataffectedthedosageincludedthecompositionandthefinenessofthecementused,andwhethertheflyashwasused.Fourgradationsofaggregatewereused,120mm-80mm:80mm-4

21、0mm:40nini-20mm:20mm-5mm=30:30:20:20.Thetermwater-to-cementitiouswasusedinsteadofwater-to-cement,andthewater-to-cementitiousratiowasmaintainedat0.50foralltheblending.Theslumpofconcretewasmaintainedatabout40mm,andtheaircontentwasmaintainedatabout5.0%intheexperimental.Afterbeingdemoulded,allthespecime

22、nswereinastandaidcuringchamber.ThemixproportionparameterofconcreteislistedinTable5.Table4EipcrlmcBtHlresultsorhydratiunhentofbondingmateriabTabic3ExperimentalrcultsofmixproportionparameterofconcreteCementMyashllydnilionbeat(kJ/kp)Eycmiienu%1d3d7dSandashrale%eMertwalefSlumpAircontentMHC0179239278%MUC

23、1067212250IMHC0527404.05.32LHC0.552740X43.26.1)MHC3015319。217iMHC0.50270913.05.1MHC401211731974LHC0.50270913.05.7MHC50)021601855MlIC0.502620875.05.06LHC0.502620IC014320522T7MHC0.502630865.15.2LHC10189212gLHC0.502630既3.1561.IK：301121511749UIIC0.4S260W3.55.0101IIC0.45260904.5611.IIC409312514

24、3IIMHC0.452520M.4.26.2l.HC50821U133121HC0.452520863.55.3PhysicalandmechanicalpropertiesThephysicalandmechanicalpropertiesincludestrength,elasticmodulus,limitstension,andsoon.TheresultsofstrengthshowninTable6indicatetheearlystrength(7dcuringages)ofLHC(oddsamples)concreteincreasesslowly.Theratiobetwee

25、n7dcompressivestrengthand28dcompressivestrengthofLHCconcreteisabout0.4,whileforMHCconcretetheratioisabout0.6.ComparedwithMHCconcrete,thegrowthrateofstrengthofLHCconcretebecomesfasterafter7dcuringages.Thecompressivestrengthfor28d,90d,180dcuringagesofLHCconcretecontaining20%offlyashis30.2MPa,43.8MPa,4

26、8.5MPa,respectively,whilethatofMHCconcretecontaining20%offlyashis28.3MPa,35.6MPa,39.8MPa,respectively.ThecontentofC2sinLHCishigherthanthatinMHC,whichresultsintheabove-mentioneddifference.Table6showsthatthestrengthgrowthrateofconcretemadewithflyashblendedcementsishigherthanthatofblankspecimens;themor

27、ethedosageofflyash,thehigherthegrowthrate.Flyashhasaglassynature,whichcanreactwithCa(OH)2.SinceCa(OH)2isahydrationproductofcement,thereactionbetweenflyashandCa(OH)25calledsecondaryhydration”,willhappenatlatishages.ThemagnitudeofCa(OH)?isaffectedbysomefactors,suchasthewater-to-cementitious,thedosageo

28、fcement.Tablc6Experimentresults()r%lrcn(*hpropertiesdTconccrtcSamplerCompressivestrcnah/MPa7dSpliticiuionbirciuIi/MPdISOdAxialtensionsircngtVMPa7d28d90dISOd2id90d7d2gd90d19.918626.533.60,1.321.691.980.871.592.0526.314623.729.90.571021.722.550.921.692.53321.732637443.51.492182.953.251.912.453.10416.9

29、35.146.951.21.402803.333.622.282.973.92316.728.355639.X12022.493.0016(12.H295611.530.243.848.51.042.122.K03.201.472.543.40714.825.333.638.?1.101.792.352.501.302.072.73X96267W545.7O.7S2072.472X9IM2.SI)3.26925.637.811.31.842.583.06JO20.940.450.11.692.994.072.402.if4.201)21.43354151.7122s2.

30、73M32.323.261217.842.713.151.732.733.66TheelasticmodulusandthelimitstensionofconcretearegiveninTable7.Undersamemixingproportion,theelasticmodulusofLHCconcreteisapproximatelyequaltothatofMHC;the28-daylimitstensionofLHCconcreteisincreasedby10 x10-6to15xlO-6thanthatofMHC,andthe90-daylimitste

31、nsionofLHCconcreteisincreasedby12x10-6thanthatofMHCconcrete.TheaboveresultsshowthattheuseofLHCimprovesthelimitstensionofconcrete.Increasingthelimitstensionofconcretewillbebenefittothecrackresistanceofconcrete.Table7EKperimcntresultsofdtismodulusandlimitstensionofconcreteSamplesIdaslismodulus/CpaLimi

32、tslens-icn/xI067d28d90d7d28d90d117J24.026.1577482116,223.625.1658392319.530.333.78493102418.828-432.290108115520.228.529.7H28X96618.527.832.9759710X719.228.930.6708491g18.926.630.17195103P25.532.836.28996.51061024.130.735.61021171201123.931.934/78590101190110116Deformationcharacteristic

33、sDeformationcharacteristicsofconcreteincludedryingshrinkage,autogenousdeformation,creep,etc.ThedryingshrinkageofconcreteisshowninFig.l.Thedryingshrinkageincreaseswithage.Atearlyagesaupto90days,alltheLHCconcretespecimensshowalowerdryingshrinkage;anditdecreaseswithincreasingtheflyashcontent.Whencontai

34、ning30%offlyash,thedryingshrinkageofLHCconcreteis363xlO-6at90days,whileforMHCconcretethevalueis408x10-6.Asaresult,thevolumestabilityofLHCconcreteisbetterthanthatofMHCconcreteindryingenvironment.*WO7500|400S.300W200B1005oMHCwith0%llyasihLHCv-iihQ%f|,yashMHCwith20%nyashLHCill)20%llyashMJICxviehJO%flya

35、slLllC-nith30%flyashCuiingagc/d.Eis.IEvoeriineniresultsofdrvs.hrinkaecrateofconcreteExperimentresultsofautogenousdeformationofconcretearegiveninFig.2.ThereisanobviousdifferencebetweenthedevelopmentofautogenousdeformationofLHCconcreteandthatofMHCconcrete.TheautogenousdeformationofLHCconcretehasanexpa

36、nsivetendency.Atearlyagesupto14days,theautogenousdeformationofpureLHCsamplesincreaseswithage,andthe14-dayvaluereachesapeakof20 x1O_6.TheautogenousdeformationofpureLHCsamplesdecreaseswithageat14daysto90days,andthe90-dayvalueis10 x1O-6.Afteradding30%offlyash,theautogenousdeformationofLHCconcreteincrea

37、seswithage,andthe90-dayvalueis61x10TheautogenousdeformationofMHCconcretehasatendencytoq-Jco-.1snouuwolnvshrink,especiallywithoutflyash.MHCwithO%flyashLHCwith0%flyash302010MHCwith30%HyashLHwith30%(ly研ed.；口一了.口Cu.ringage/dIia.2Experimentresullsofautoacnousdcforniaiionofconcrete33DurabilityaThedurabili

38、tyofconcreteisevaluatedbyantipenetrabilitygradeandfrost-resistantlevel.Underthepressureof1.2MPa,thepermeabilityheightofpureLHCsamplesis3.1cm,whilethatofpureMHCsamplesis2.0cm.ThetestdataindicatethattheLHCconcretehasanexcellentperformanceinanti-penetrability,aswellasMHCconcrete.Thepermeabilityofconcre

39、teincreasessomewhatwithadditionofflyash.Attheendofthe250freezingandthawingcycling,thereisalittledifferenceinbothmassandresonantfrequency.BothLHCconcreteandMHCconcreteshowanexcellentfrost-resistantbehavior.TheresultsofthisworkconfirmthatLHCconcretesystemshaveanadequateanti-penetrabilityandfrost-resis

40、tancetoadaptingdesignrequirement.3.4AnalysisofcrackresistanceInordertocontrolthecrackphenomena,itisimportanttoaccuratelyevaluatetheanti-crackbehavior.Aswellknown,concreteisakindoftypicalbrittlematerials,anditsbrittlenessisassociatedwiththeanti-crackbehavior1l?l.Thebrittlenessismeasuredbytheratioofte

41、nsionstrengthtocompressivestrength.Withtheincreaseoftheratio,concretehasalessbrittleness,bettercrackresistanceandtoughness.ItisindicatedfromtheexperimentresultsshowninTable6thattheratioofLHCconcreteatallstagesofhydrationishigherthanthatofMHCconcrete,whichshowsthatLHCconcretehasabetteranti-crackbehav

42、ior.Inthecrackcontrolanddesignofhydroelectricmassconcrete,theoriginalevaluationofcrackresistancebehaviorofconcreteisusingtheutmosttensilestrengthwhichisshowninthefollowingexpressionofEq.l.o=epE(1)where,ePisthelimitstensionofconcrete,andEistheelasticmodulusoftension,whichisassumedtobeequaltotheelasti

43、cmodulusofcompression1161.ItisindicatedfromthecalculationresultsshowninTable8thattheutmosttensilestrengthofLHCconcreteatallstagesofhydrationishigherthanthatofMHCcncrete.Tttblc8Anti-crackstrciiKlhofconcreteSamplesCcmsiUAnti-crackstrengthAMPa7d28d90dtMHC1.011.782J42MIC1.051.962.323MHC1.642.823.444LHC1

44、.693.073-705MlIC1.662.5!2.S56LHC1.392.73.557MHC1.342.432.78KLIIC1.342.533J09MHC2.273.173.8410LHC61594.2711MHC2.032.X73.5012I.IIC2.173.543.86Theresearchonmaterialscrackresistancewhichisthebasisforesign,constnictionandthechoiceofrawmaterials,hasbeenpopularintodaysworld.Throughagreatdealofresearch,itis

45、widelythoughtthatconcretewithabettercrackresistancehasahighertensionstrengthandlimitstension,lowerelasticodulusandadiabatictemperatureriseandbettervolumestability117181.Basedonabove-mentionedresults,theLHCconcretehasahighertensionstrengthandlimitstension,lowerelasticmodulusandadiabatictemperatureris

46、e,andlowerdryingshrinkagethanMHCconcrete.ComparedwithMHCconcrete,theautogenousdeformationofLHCconcretehasanexpansivetendency.AlthoughtheearlystrengthofLHCconcreteislowerthanthatofMHCconcrete,itslaterstrengthhasapproachedtoorevenexceedthatofMHCconcrete.4ConclusionsTheearlycompressivestrength(7dcuring

47、ages)ofLHCislower,butitslaterstrength(28d,90dcuringages)hasapproachedtoorevenexceedthatofMHC.ComparedwithMHC,theaveragehydrationheatofLHCconcreteisreducedbyabout17.5%.Underthesamemixingproportion,theelasticmodulusofLHCconcreteisapproximatelyequaltothatofMHC,andthelimitstensionofLHCconcreteisincrease

48、dby10 x1O-6-15x1O6thanthatofMHC.ThedryingshrinkageofLHCconcreteisobviouslysmallerthanthatofMHCconcrete,andtheautogenousdeformationofLHCconcretehasatendencytoexpand.e)TheLHCconcretehasabetteranti-penetrabilityandfrostresistance,aswellastheMHCconcrete.Atallstagesofhydration,theanti-crackstrengthofLHCc

49、oncreteishigherthanthatofMHCconcrete,andtheformerhasahigherratiooftensionstrengthtocompressivestrength.References1CXYu,ZKong.ResearchontheCausesofCracksinMassConcreteandControlMeasuresJ.LowTemperatureArchitectureTechnology(China),2005(5):112-1132AAAlmusallam,MMaslehuddin.EffectofMixProportionsonPlas

50、ticShrinkageCrackingofConcreteinHotEnvironnientsJ.ConstructionandBuildingMaterials,1998(12):353-358XuJingan,AnZhiweii.CountenneasureofTemperatureCrackofMassConcreteJ.JournalofHebieInstituteofArchitecturalEngineering,2005,23(3):36-40PengWeibing,RenAizhu.EffectsandEvaluationonCrackingofConcreteIncorpo

51、ratingSupplementaryCementitiousMaterials!J.Concrete(China),2005(6):50-64XiaoReimin,ZhangXiong.EffectofBinderonDryingShrinkageofConcrete.ChinaConcreteandCementProducts,2002(5):11-13YeQing,ChenXin.ResearchontheExpansiveMechanismofModerateHeatPortlandCementwithSlightExpansionJ.JournaloftheChineseCerami

52、cSociety,2000,128(4):335-347ShiXun.ApplicationofSlightExpansionCementonConcreteofStageIIWorksoftheThreeGorgesProjectJ.Cement(China).2002(5):12-14Nagaokas,MizukosuiM.PropertyofConcreteUsingBeliterichCementandTernaryBlendedCementJ.JournaloftheSocietyofMaterialsScience,Japan.1994,43(491):488-492GeJunca

53、i.TechnologyProgressofCementandConcreteM.Beijing:ChinaBuildingMaterialIndustryPress,1993:275-276MethaPK.InvestigationonEnergy-savingCementJ.WorldCementTechnology,1980,1(3):166-177Taylor.CementChemisttyM.London:AcademicPress,1990:142-152SuiTongba,LiuKezhong.AStudyonPropertiesofHighBeliteCementJ.Journ

54、aloftheChineseCeramicSociety,1999,127(4):488-492YangNanru,ZhongBaixi.StudyonActive-C2sC.SymposiumonCement,1983:180-185YangHuanquan,LiWenwei.ResearchandApplicationofHydroelectricConcreteM.Beijing,ChinaWaterPowerPress,2004:393-394ERingot,ABascouLAbouttheAnalysisofMicro-crackinginConcreteJ.CementandCon

55、creteComposites,2001(23):261-266LiGuangwei.AssessmentforAnti-CrackPerformanceofConcreteJ.AdvancesinScienceandTechnologyofWaterResources(China),2001,21(2):33-36LiuShuhua,FangKunhe.SummarizationofNormofCrackResistanceofConcreteJ.Highway(China2004(4):eJ105-107低热硅酸盐水泥混凝土的抗裂性能摘要：低热硅酸盐水泥混凝土(LHC)的特性详细地被研究。

56、实验的结果表示LHC混凝土有比较高实际的机械行为、形变和耐久性的特性。与中热硅酸盐水泥(MHC)相较，LHC混凝土的平均水合作用热被减少大约17.5%,在相同的混台比例比率之下，LHC混凝土的断热温升减少了2-3,而且LHC混凝土的限度张力比MHC增加了10X1090d、180d后的抗压强度分别是30.2MPa、43.8MPa、48.5MPa,含20%粉煤灰的MHC混凝土在28d、90d.180d后的抗压强度分别是28.3MPa、35.6MPa、39.8MPa。造成上述差异的原因是LHC的C2s含量比MHC高。表6表示与参入粉煤灰的水泥的强度增长率比不加的的高；粉煤灰的添加量愈多,增长率也愈高

57、。粉煤灰有玻璃的性质，可以与Ca(OH)2反应。因为Ca(OH)2是水泥的水水化产物，粉煤灰和Ca(OH)2之间的反应,被称为“第二水化反应”，将在迟些时候发生。Ca(OH)2的多少被一些因数影响，比如水浆体，水泥的添加量。Table6ExperimentresultsofslrcnghprcipcrticsofconccrtcSamplerCompressivestra)Kh/MPaSpliticiisioiisirciuh/MPdAxialtensionstrcnghMPa7d2gd90dISOd7d2gd90dl$0d7d2gd90d526.32so.9.5)57229o.M52.359

58、46.2.33二30.25c?2739I2220-、793573)72.4223.5.o3.o-I220.3436959252.273.o.74.2.15在表7中给模量和屈服极限。在相同的混合比例下，LHC混凝土的弹性模量和MHC大约相等:LHC混凝土的28天的屈服极限比MHC增长了10X1015XIO6,而LHC混凝土的90天的屈服极限超过了MHC混凝土12X10q上述的结果表明LHC的使用改良了混凝土的屈服极限。增加混凝土的屈服极限将会有利于混凝土的裂痕的出现。Tabic7Experimentresultsofelasticmodulusandlimitstensionofconcrete

59、SamplesEiastismoduius/CipaLimitstension/x107d28d90d7d28d90d117.724.026.1577482216.223.625.265X392319.5J0.333.7S493102418.828.432.290108115520.228.529.7828896618.527.X32.97597IOS719.228.930.6708491818.926.6305J2.836.28996.51061024.130.735.61021171201123.931.934.7859010119011

60、01163.2形变特征混凝土的形变特性含干燥收缩、自生的形变、潜动等等。Fig.l显示了混凝士的干燥收缩。干燥收缩是随时间增加的。在刚到90天时，所有的LHC混凝士试样表示一个低的干燥收缩；而且它随着粉煤灰的增加而降低。当粉煤灰的含量为30%是，LHC混凝土在90天的干燥收缩为363X10”,而为MHC混凝土数值是408X10-6。结果，LHC混凝土的安定性在干燥环境中比MHC混凝士好。360075004002,300W200ilooSoMHCwich0%OyasihUICYiih。%flyashMHCwieh20%tlyashoI.IICilh20%nyashMICwithSO%fiyfiS