土木工程混凝土強(qiáng)度中英文對照外文翻譯文獻(xiàn)

中英文對照外文翻譯(文檔含英文原文和中文翻譯)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譯文:混凝土強(qiáng)度與混凝土澆筑方向關(guān)系的研究摘要從理論上看，假設(shè)混凝土復(fù)合材料是各項同性的從宏觀尺度上講。例如，假定在所有的方向樓板或梁的強(qiáng)度是相同并且它的非均勻性是隨機(jī)的。因此，倘若既不計算結(jié)構(gòu)構(gòu)件的承載能力，也不考慮結(jié)構(gòu)中混凝土的技術(shù)，在考慮到足夠程度的情況，關(guān)于混凝土各向同性的假設(shè)是過于樂觀的。目前的研究表明，在沿澆筑方向混凝土強(qiáng)度有變化不只是一個定性的影響（正如人們普遍認(rèn)為的），但也有顯著的定量效應(yīng)。這說明混凝土是一種尚未被完全認(rèn)識的復(fù)合材料。本文介紹了普通混凝土（OC）同質(zhì)性構(gòu)件厚度沿澆筑方向的評價。超聲波法和混凝土接觸點修正指數(shù)頭被用在研究[1-3]。關(guān)鍵詞：混凝土；混凝土抗壓強(qiáng)度；非破壞性介紹在一個建筑結(jié)構(gòu)中，有一部分是具有特殊性質(zhì)的，但不一定是在整個截面上的。例如梁、樓板這樣的彎曲部件，一般都是在其上部受壓，而混凝土的抗壓強(qiáng)度則主要是在這個區(qū)域內(nèi)。組件通常在一直被保養(yǎng)的位置壓模，即在壓縮下的上部區(qū)域。在上部區(qū)域的混凝土被認(rèn)為將略弱于在較低的區(qū)域，但目前尚不清楚有弱了多少[4,5]。生產(chǎn)大廳的地板是最容易磨損和沖擊載荷，在其上部區(qū)域不是他們最強(qiáng)的部分。在實踐是我們都知道工業(yè)地板屬于最經(jīng)常損壞的建筑組件。他們只能從鋼筋混凝土梁或樓板的底面進(jìn)行試驗，在此基礎(chǔ)上得到整個截面的混凝土強(qiáng)度的結(jié)果，包括在壓縮的上部區(qū)域。因此而產(chǎn)生的一個問題：在類似的這種試驗中的錯誤有多少？為了回答上述問題和其他問題，在各種結(jié)構(gòu)構(gòu)件混凝土強(qiáng)度試驗，特別是在混凝土板上，進(jìn)行了STR的變化沿元件厚度長度分析。研究意義本文提出的研究結(jié)果表明，在水平形成的結(jié)構(gòu)元件的混凝土抗壓強(qiáng)度隨厚度變化。板頂部區(qū)域的強(qiáng)度是25%-30%要低于板中部區(qū)域強(qiáng)度，他們遠(yuǎn)低于強(qiáng)度為100%的板底部區(qū)域。觀察基于上無損檢測的結(jié)果，即從結(jié)構(gòu)上的鉆芯，并通過一個破壞性的方法驗證。值得注意的是，雖然混凝土技術(shù)的巨大進(jìn)步，但是在沿著厚度的混凝土抗壓強(qiáng)度變化是在舊的混凝土（超過60年)和當(dāng)代普通混凝黏土的特點。試驗方法在混凝土強(qiáng)度測試前，先用指數(shù)型頭接觸混凝土的超聲波方法進(jìn)行了測試。指數(shù)頭的詳細(xì)數(shù)據(jù)可以找到[2,3]。頭的頻率為40和100千赫，其濃縮機(jī)直徑達(dá)1毫米。為確定在現(xiàn)有結(jié)構(gòu)的實際強(qiáng)度分布，用圓柱芯為80毫米或114毫米直徑的鉆，從混凝土澆筑方向鉆孔。直到與其直徑高度一致的樣本核心被切出來。根據(jù)圖3所示的方案進(jìn)行對核心的超聲波測量。超聲波脈沖是通過在垂直的每間隔10毫米的兩個方向I和II。這樣就可以確定沿核心的高度變化的速度，即沿測試元件的厚度.由兩個測試方向的平通時間測定和計算速度CL。由測試平面兩個方向測得的速度是個均值。隨后，從核芯中切出高度等于其直徑即80毫米的試樣。試樣的中心區(qū)平均超聲波脈沖速度CL和疲勞強(qiáng)度fc由強(qiáng)度測試儀中進(jìn)行的破壞性測試所確定。不