土木工程混凝土强度中英文对照外文翻译文献

中英文对照外文翻译(文档含英文原文和中文翻译)原文:StrengthofConcreteinSlabs,InvestigatesalongDirectionofConcretingABSTRACTIntheoryofconcreteitisassumedthatconcretecompositesareisotropiconamacroscale.Forexample,itisassumedthatafloorslab’sorabeam’sstrengthisidenticalinalldirectionsanditsnonhomogeneityisrandom.Henceneithercalculationsoftheload-bearingcapacityofstructuralcomponentsnorthetechniquesofinvestigatingconcreteinstructureinsitutakeintoaccounttoasufficientdegreethefactthattheassumptionaboutconcreteisotropyisoverlyoptimistic.Thepresentresearchshowsthatvariationinconcretestrengthalongthedirectionofconcretinghasnotonlyaqualitativeeffect(asiscommonlybelieved),butalsoasignificantquantitativeeffect.Thisindicatesthatconcreteisacompositewhichhasnotbeenfullyunderstoodyet.Thepaperpresentsevaluationsofordinaryconcrete(OC)homogeneityalongcomponentthicknessalongthedirectionofconcreting.Theultrasonicmethodandmodifiedexponentialheadswithapointcontactwithconcretewereusedintheinvestigations[1-3].Keywords:Concrete;CompressiveStrengthofConcrete;Non-Destructive1.IntroductionInabuildingstructuretherearecomponentswhichareexpectedtohavespecialpropertiesbutnotnecessarilyinthewholecrosssection.Componentsunderbending,suchasbeamsandfloorslabsaregenerallycompressedintheirupperzoneandtheconcrete’scompressivestrengthisvitalmainlyinthiszone.Thecomponentsareusuallymouldedinthesamepositioninwhichtheylaterremaininservice,i.e.withtheirupperzoneundercompression.Concreteintheupperzoneisexpectedtobeslightlyweakerthaninthelowerzone,butitisunclearhowmuchweaker[4,5].Alsoflooringslabsinproductionhallsaremostexposedtoabrasionandimpactloadsintheirupperzonewhichisnottheirstrongestpart.Itisknownfrompracticethatindustrialfloorsbelongtothemostoftendamagedbuildingcomponents.Whenreinforcedconcretebeamsorfloorslabsaretobetestedtheycanbeaccessedonlyfromtheirundersidesandsoonlythebottompartsaretestedandonthisbasisconclusionsaredrawnaboutthestrengthoftheconcreteinthewholecrosssection,includinginthecompressedupperzone.Thusaquestionarises:howlargearetheerrorscommittedinthiskindofinvestigations?Inordertoanswertheaboveandotherquestions,testsofthestrengthofconcreteinvariousstructuralcomponents,especiallyinhorizontallyconcretedslabs,werecarriedout.Thevariationofstrengthalongthethicknessofthecomponentswasanalyzed.2.ResearchSignificanceTheresearchresultspresentedinthepapershowthatthecompressivestrengthofconcreteinhorizontallyformedstructuralelementsvariesalongtheirthickness.Inthetopzonethestrengthisby25%-30%lowerthanthestrengthinthemiddlezone,anditcanbebyasmuchas100%lowerthanthestrengthinthebottomzone.Theobservationsarebasedontheresultsofnondestructivetestscarriedoutondrillcorestakenfromthestructure,andverifiedbyadestructivemethod.Itisinterestingtonotethatdespitethegreatadvancesinconcretetechnology,thevariationincompressivestrengthalongthethicknessofstructuralelementsischaracteristicofbothold(over60yearsold)concretesandcontemporaryordinaryconcretes.3.TestMethodologyBeforeConcretestrengthwastestedbytheultrasonicmethodusingexponentialheadswithapointcontactwithconcrete.Thedetailedspecificationsoftheheadscanbefoundin[2,3].Theheads’frequencywas40and100kHzandthediameteroftheirconcentratorsamountedto1mm.Inordertodeterminetherealstrengthdistributionsintheexistingstructures,cylindricalcores80mmor114mmdiameter(Figure2)weredrilledfromtheminthedirectionofconcreting.Thenspecimenswiththeirheightequaltotheirdiameterwerecutoutofthecores.UltrasonicmeasurementswereperformedonthecoresaccordingtotheschemeshowninFigure3.Ultrasonicpulses(pings)werepassedthroughintwoperpendiculardirectionsIandIIinplanesspacedevery10mm.Inthiswayonecoulddeterminehowpingvelocityvariedalongthecore’sheight,i.e.alongthethicknessofthetestedcomponent. InbothtestdirectionspingpasstimesweredeterminedandvelocitiesCLwerecalculated.Thevelocitiesfromthetwodirectionsinatestedmeasurementplanewereaveraged.Subsequently,specimenswiththeirheightequaltotheirdiameterof80mmwerecutoutofthecores.Aver-ageultrasonicpulsevelocityCLforthespecimen’scentralzonewascorrelatedwithfatiguestrengthfcdeterminedbydestructivetestscarriedoutinastrengthtester.Forthedifferentconcretesdifferentcorrelation curveswithalinear,exponentialorpowerequationwereobtained.Exemplarycorrelationcurveequationsaregivenbelow: where: fc—thecompressivestrengthofconcreteMPa,CL—pingvelocitykm/s. Thedeterminedcorrelationcurvewasusedtocalculatethestrengthofconcreteineachtestedcorecrosssectionandtheresultsarepresentedintheformofgraphsillustratingconcretestrengthdistributionalongthethicknessofthetestedcomponent.4.InvestigationofConcreteinIndustrialFloorsAfterFloorinsugarfactory’srawmaterialsstoragehallConcreteinanindustrialfloormusthaveparticularlygoodcharacteristicsinthetoplayer.Sinceitwastobeloadedwithwarehousetrucksandstoredsugarbeetsandfrequentlywashedtheinvestigatedconcretefloor(builtin1944)wasdesignedasconsistingofa150mmthickunderlayanda50mmthicksurfacelayerandmadeofconcretewithastrengthof20MPa(concreteA).Aspartoftheinvestigationseightcores,each80mmindiameter,weredrilledfromthefloor.Theinvestigationsshowedsignificantdeparturesfromthedesign.Theconcretesubfloor’sthicknessvariedfrom40to150mm.Thesurfacelayerwasnotmadeofconcrete,butofcementmortarwithsandusedastheaggregate.Alsothethicknessofthislayerwasuneven,varyingfrom40to122mm.Aftertheultrasonictestsspecimenswiththeirheightequaltotheirdiameterof80mmwerecutoutofthecores.Twoscalingcurves:oneforthesurfacelayerandtheotherforthebottomconcretelayerweredetermined.Acharacteristicconcretecompressivestrengthdistributionalongthefloor’sthicknessisshowninFigure4.Strengthintheupperzoneismuchlowerthaninthelowerzone:rangingfrom4.7to9.8MPaforthemortarandfrom13.9to29.0MPafortheconcretelayer.Theverylowstrengthoftheupperlayerofmortaristheresultofstrongporositycausedbyairbubblesescapingupwardsduringthevibrationofconcrete.Figure5showsthespecimen’sporoustopsurface.FloorinwarehousehallwithforklifttrucktransportThefloorwasbuiltin1998.Cellularconcretewasusedasfortheunderlayandthe150mmthicksurfacelayerwasmadeofordinaryconcretewithfibre(steelwires)reinforcement(concreteB).Cores80mmhighand80mmindiameterweredrilledfromthesurfacelayer.Ultrasonicmeasurementsanddestructivetestswereperformedasdescribedabove.Alsothetestresultswerehandledinasimilarway.Anexemplarystrengthdistributionalongthefloor’sthicknessisshowninFigure6.5.ConclusionsTestsofordinaryconcretesshowunexpectedlygreatlyreducedstrengthintheupperzoneofhorizontallymouldedstructuralcomponents.Thisistoalargedegreeduetothevibrationofconcreteasaresultofwhichcoarseaggregatedisplacesdownwardsmakingthelowerlayersmorecompactwhileairmovesupwardsaeratingtheupperlayersandtherebyincreasingtheirporosity.Theincreaseintheconcrete’sporosityresultsinalargedropinitscompressivestrength.Thankstotheuseoftheultrasonicmethodandprobeswithexponentialconcentratorsitcouldbedemonstratedhowthecompressivestrengthofordinaryconcreteisdistributedalongthethicknessofstructuralcomponentsinbuildingstructures.Itbecameapparentthatthereductionincompressivestrengthinthecompressedzoneofstructuralcomponentsunderbendingandinindustrialconcretefloorscanbeverylarge(amountingtoasmuchas50%ofthestrengthoftheslab’slowerzone).Thereforethisphenomenonshouldbetakenintoaccountatthestageofcalculatingslabs,reinforcedconcretebeamsandindustrialfloors[6].Theresultsofthepresentedinvestigationsapplytoordinaryconcretes(OC)whichareincreasinglysupplantedbyself-compactingconcretes(SCC)andhigh-performanceconcretes(HPC).Sincenointensivevibrationisrequiredtomouldstructuresfromsuchconcretesonecanexpectthattheyaremuchmorehomogenousalongtheirthickness[7].Thiswillbeknownoncetheongoingexperimentalresearchiscompleted.BohdanStawiskiStrengthofConcreteinSlabs,InvestigatesalongDirectionofConcreting[D]InstituteofBuildingEngineering,WroclawUniversityofTechnologyWybrzezeWyspianskiego,Wroclaw,PolandReceivedOctober15,2011;revisedNovember21,2011;acceptedNovember30,2011译文:混凝土强度与混凝土浇筑方向关系的研究摘要从理论上看，假设混凝土复合材料是各项同性的从宏观尺度上讲。例如，假定在所有的方向楼板或梁的强度是相同并且它的非均匀性是随机的。因此，倘若既不计算结构构件的承载能力，也不考虑结构中混凝土的技术，在考虑到足够程度的情况，关于混凝土各向同性的假设是过于乐观的。目前的研究表明，在沿浇筑方向混凝土强度有变化不只是一个定性的影响（正如人们普遍认为的），但也有显著的定量效应。这说明混凝土是一种尚未被完全认识的复合材料。本文介绍了普通混凝土（OC）同质性构件厚度沿浇筑方向的评价。超声波法和混凝土接触点修正指数头被用在研究[1-3]。关键词：混凝土；混凝土抗压强度；非破坏性介绍在一个建筑结构中，有一部分是具有特殊性质的，但不一定是在整个截面上的。例如梁、楼板这样的弯曲部件，一般都是在其上部受压，而混凝土的抗压强度则主要是在这个区域内。组件通常在一直被保养的位置压模，即在压缩下的上部区域。在上部区域的混凝土被认为将略弱于在较低的区域，但目前尚不清楚有弱了多少[4,5]。生产大厅的地板是最容易磨损和冲击载荷，在其上部区域不是他们最强的部分。在实践是我们都知道工业地板属于最经常损坏的建筑组件。他们只能从钢筋混凝土梁或楼板的底面进行试验，在此基础上得到整个截面的混凝土强度的结果，包括在压缩的上部区域。因此而产生的一个问题：在类似的这种试验中的错误有多少？为了回答上述问题和其他问题，在各种结构构件混凝土强度试验，特别是在混凝土板上，进行了STR的变化沿元件厚度长度分析。研究意义本文提出的研究结果表明，在水平形成的结构元件的混凝土抗压强度随厚度变化。板顶部区域的强度是25%-30%要低于板中部区域强度，他们远低于强度为100%的板底部区域。观察基于上无损检测的结果，即从结构上的钻芯，并通过一个破坏性的方法验证。值得注意的是，虽然混凝土技术的巨大进步，但是在沿着厚度的混凝土抗压强度变化是在旧的混凝土（超过60年)和当代普通混凝黏土的特点。试验方法在混凝土强度测试前，先用指数型头接触混凝土的超声波方法进行了测试。指数头的详细数据可以找到[2,3]。头的频率为40和100千赫，其浓缩机直径达1毫米。为确定在现有结构的实际强度分布，用圆柱芯为80毫米或114毫米直径的钻，从混凝土浇筑方向钻孔。直到与其直径高度一致的样本核心被切出来。根据图3所示的方案进行对核心的超声波测量。超声波脉冲是通过在垂直的每间隔10毫米的两个方向I和II。这样就可以确定沿核心的高度变化的速度，即沿测试元件的厚度.由两个测试方向的平通时间测定和计算速度CL。由测试平面两个方向测得的速度是个均值。随后，从核芯中切出高度等于其直径即80毫米的试样。试样的中心区平均超声波脉冲速度CL和疲劳强度fc由强度测试仪中进行的破坏性测试所确定。不