4讲砼及其施工.docx
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4讲砼及其施工.docx
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4讲砼及其施工
第一部分
科技英语相关知识介绍(四)
长句翻译
1.长句特点
指结构复杂的句子,又叫大复合句,一般为主从复合句或并列句。
特点:
●修饰语较多、较长。
有多个错综复杂的关系
●定语从句、状语从句、同位语从句、短语等的存在形式:
嵌套式:
一个套一个,一个套数个
并列式:
两者并列、三者并列
2.分析方法
长句的关键是语法分析。
先判断是何种句子,再找主要成分。
化繁为简—将整体分解为部分
化难为易—将复杂的事物分解为简单的要素
深入浅出—层层分解,逐一剥离,去其枝叶,留其主干。
(1)先找句子中有几个谓语、几个连词(如and、when等)、几个关联词(如which、that等)。
如不是并列谓语,就可根据谓语再找相应的主语,把长句化为几个简单句。
Whenabodywhichhasacertaintemperaturebecomeshotterwesaythatheathasbeenaddedtoit.
四个主语、四个谓语、三个连词和关联词。
无连词和关联词的句子显然是主句。
译文:
当具有一定温度的物体变为更热时,我们说有热量加到该物体上去了。
(2)注意从句套从句的复杂现象。
Wemustthereforeconcludethatwhenthedistancebetweenthemoleculesisverysmall,thereareforcesofrepulsionandthattheseforcesincreaserapidlyasthedistancebetweenthemoleculesdecreases.
两个宾语从句,又各自带一个从句。
译文:
因此,我们必须断言:
当分子之间的距离很小时,就产生排斥力,并且这种排斥力随着分子之间的距离减小而迅速增加。
If,afterabodyisdeformedbysomeforce,itreturnstoitsoriginalshapeorsizeasthedistortingforceisremoved,thematerialissaidtobeelastic.
条件从句内嵌有时间从句和原因从句,主句在最后。
译文:
如果在物体受某一力变形后,由于移去该力而使物体又恢复原来形状和大小,则我们说这种材料具有弹性。
(3)注意toV.、-ing、V.ed在句中作次要成分时又嵌有从句的现象。
Thestressdistributionassociatedwithfailureisofparticularimportancesincethisdistributionisneededinthederivationofdesignequationsrelatingtheultimateflexuralstrength,whichtheACICodecallsthenominal(额定的)momentcapacity,tothecross-sectionaldimensions,theareaofreinforcement,andthestrengthofthematerials(asmeasuredbyfcandfy).
开头无其他关联词,显然是主句:
应力分布特重要。
在relating…to…分词短语中含有非限制性定语从句。
参考译文:
与破坏有关的应力分布特重要,因为在推导极限抗弯强度(美国混凝土学会规范称为额定弯矩能力)与横截面大小、钢筋面积以及材料强度(用fc和fy来度量)之间的设计关系式时需要该分布。
(4)注意成分割裂
Inafluidthatisinmotionthereisadecreaseinpressurewherethespeedisincreased,andanincreaseinpressurewherethespeedisdecreased.
两个并列主语(decrease、increase)被中间的地点状语从句隔开。
译文:
在运动的流体内,速度增加的地方其压力就减小,而速度减小的地方其压力就增加。
(5)注意省略成分
Therearethreethingswehavetoknowabouteveryforceinordertobeabletounderstandtheeffectitproduced.
句中有三个主语、三个谓语,没有连词和关联词,意味着有省略,在we和it前面省掉的which。
译文:
为了了解每个力所产生的效果,我们必须知道力的三要素。
(6)注意词的搭配和前后呼应的连词或关联词
如上面的relating…..to….
Wemayspeakofanythingwhosevoltageishigherthanthatoftheearthasbeingpositive.
注意Speakof和as的搭配关系,as引出宾语补语。
宾语补语前又插上一个定语从句(whose引导)。
我们可以把凡是比大地电位高的物体说成是带正电的。
3.小结
(1)一般来说,先找谓语、连词、关联词,然后找各谓语相应的主语(如主语明显,也可先确定主语),把长句分成几个简单句。
(2)若没有并列的谓语,则有几个谓语就有几个句子(含从句)。
可利用这一特点来判别句中连词或关联词省略情况。
(3)搞清各简单句的意思,并把各句联系起来,确定其间意义关系。
(4)结合上下文把长句译成汉语。
但句意必须合乎道理。
如句意讲不同,就得重新分析句子。
遇到长句莫犯难,繁化简来长化短。
主谓宾补一条线,主句动词是关键。
插入句子暂忽略,连、介、标点结构断。
词的搭配要明确,前后呼应把线牵。
主次涵义要分清,译时要从汉习惯。
从句短语起止明,修饰对象莫混乱。
第二部分课文学习
4.Concrete
Concreteisacarefullyproportionedmixtureofcement,water,fineaggregate,andcoarseaggregate.Tothesebasiccomponents(组分)avarietyofadmixtures(添加剂),i.e.,chemicalsthatinfluence(影响)thereactionormodify(改进)thephysicalpropertiesofthehardenedconcrete,arefrequentlyadded.Assoonasthecomponentsofconcretehavebeenmixedtogether,thecementandthewaterreacttoproduceacementing(粘结)gel(凝胶体)thatbonds(结合、粘结)thefineandthecoarseaggregatesintoastonelikematerial.Thechemicalreactionbetweenthecementandwater,anexothermic(放热的)reactionproducingsignificant(可观的、大量的)quantitiesofheat,istermedhydration(水化反应)
Duringtheinitial(初始)stagesofhydration,whenonlysmallamountsofgelhaveformed,theconcreteisinaplasticstateandflowseasily.Throughoutthisstagetheconcretecanbedeposited(浇注、沉淀)informs,workedintothespacesbetweenreinforcement(钢筋),andcompacted(捣固)toeliminate(消除)voids,andthesurfacescanbeleveled(整平)andfinished(抹光).Ashydrationcontinuesandlargeramountsofgelform(形成),theconcreteprogressivelystiffens(硬化),losesitsworkability(可塑性、和易性),andgainsstrength.
Therateatwhichthegelformsisinfluencedbythetemperatureatwhichthereactionoccurs.Athightemperaturesthereactionisrapid:
only10or15min.mayberequiredfortheconcretetostiffen.Atlowtemperatures10to12hoursmayberequiredtoproducethesamedegreeofstiffness(硬度、强度、刚度).Thefinalproductconsistsofthevarious-sizedaggregatessurrounded(包围)byamortarcomposedofcementandthefineaggregates.Ideally,engineerswouldliketoproduceadense(致密的)homogeneous(均匀的)concretethatisfreeofvoids,channels(通道),cracks(裂纹),andotherdefects(缺陷).Suchamaterialwouldhaveuniformstrengthproperties,beimpermeable(不渗透的)towater,andpresent(呈现)anattractivesurfaceappearance(外表).Asapracticalmatter,however,itisnotpossibletoproduceconcretethatisfreeofflaws(裂缝、毛病):
eventhemostcarefullycontrolledconcreteshaveavarietyofsmallinternalandsurfacedefects.Voidsarecreatedbyairbubbles(气泡)producedduringthemixingprocessandbysegregation(分离、离析)ofthecoarseaggregatefromthemortarwhenconcreteisdepositedinforms.Sinceapproximatelytwiceasmuchwaterisneededforworkabilitythanisrequiredtoreactwiththecement,finechannelsdevelopthroughouttheconcreteasexcess(过量的)waterrisestothesurfacewhentheconcreteisvibrated(震捣).Theriseofthewatertothesurfaceistermedbleeding(泛浆).
Surfacedefectssuchaspits(坑、麻点)andhoneycomb(蜂窝)(theabsenceofmortarbetweenaggregates)developwhentheconcretecontainsinsufficientmortarorwhentheconcreteisnotproperly(充分地)compactedinforms.Inaddition,x-rayandmicroscopic(显微镜的)studiesshowthatfinemicrocracksdevelopasaresultoftherupture(断裂)ofthebondbetweenthegelandtheaggregate.
Thebreakinbondisprimarilyattributedto(归于)dryingandcarbonation(炭化)shrinkage(收缩)(shrinkageproducedbyexposureto(由于受到…影响)CO2).Thepresenceoftheseinternalflawsexplainsinpartthelargedifferencebetweenthetensileandthecompressivestrengthsofconcrete.
MostconcreteproducedinthiscountryismadewithPortlandcements.Termedhydrauliccements(水硬水泥)becausetheyreactwithwater,theyhavetheabilitytohardenunderwater.Portlandcementsareavaliable(可行的、可用的)infiveASTM(AmericanSocietyforTestingandMaterials)types.Theyaremanufactured(生产)fromthesamebasicmaterials,buttheirpropertiesarealtered(改变)somewhat(多少、稍微)bythewaytherawmaterials,oftenclaysandlimestones,areblended(参合)andfiredbeforetheyareground(研磨)intocementpowder(粉).
Aggregates,whichconstitute(占)approximately75percentoftheconcretevolume,areusuallycomposed(组成)ofwell-gradedgravelorcrushedstone.Aggregatespassingano.4sieve(筛)[thewiresofthescreen(筛)arespaced1/4in(6.4mm)apart]areclassifiedasfineaggregates;largeraggregatesareclassifiedascoarseaggregates.Sincethepresenceofdustorchemicalscanweakenthebondbetweenthecementinggelandtheaggregates,strong,durable(耐久的)concretesrequireaggregatesthatarecleanandhard.Unreinforcedconcretesmadewithstoneorgravel(砾石)arenormallyassumedtoweigh2320kg/m3.Whenreinforcement(钢筋)isadded,theweightofconcreteandsteelisgenerallytakenas2400kg/m3fornormal-weightaggregates.
Ifthedesignerwishestoreducetheweightofconcretemembersthatarenotsubjected(承受、遭受)toheavywearorabrasion(磨损),lightweightaggregates,madefromavarietyofexpandedshalesandslags,canbesubstituted(取代)fortheheavierstoneorgravelaggregates.Concretesthathavea28-daystrengthequaltoorgreaterthan17.24MPaandanair-dryweightlessthan1840kg/m3aretermedstructurallightweightconcrete(结构轻混凝土).Ifallaggregates(boththefineandthecoarse)arelightweight,theconcreteiscalledall-lightweight(全轻砼).Ifthecoarseaggregateislightweightandthefineaggregateissand,theconcreteistermedsand-lightweightconcrete(砂轻砼).
Unlessfield(现场)practiceverifies(证明)thatconcretewithacertainsizeaggregatecanbesuccessfullyplacedandcompacted,ACICoderequiresthatthemaximumsizeofcoarseaggregatenotexceed:
(1)One-fifthofthesmallestdimension(尺寸)oftheforms;
(2)One-thirdthedepthofslabs(楼板);(3)Three-fourthsoftheminimumclearspacing(净间距)betweenreinforcement.
Toproducehigh-qualityconcrete,sufficientwatermustbeaddedtomaketheconcretefluidsoitcanbeworkedintoallpartsofthecontainingforms(挡模、围模).However,ifexcessiveamountsofwaterareadded,aweak,high-shrinkingconcretewillresult.Theslump(坍落度)testisacommonfieldtestusedtocontroltheworkabilityandqualityofconcrete(Fig.4.1).
Intheslumptesta12-in(305mm)steeltruncated(截去…顶端)cone(锥体)placedonalevelbaseisfilledwithfreshconcrete,compactedbyrodding.Afterthetopsurfacehasbeenleveled,theslumpconeisslowlylifted.Lacking(缺少)lateralsupport,theconcreteslumps.Thedifferenceinheightmeasuredininchesbetweenthetopoftheconcreteandthetopoftheslumpconeiscalledtheslump.Concretesaretypically(标准化地)producedwithslumpsrangingfrom2to6in(51to152mm).Thebiggestslumpsarespecified(规定)forconstructionusingnarrow(窄的)formscontainingalargenumberofbars.
PlacingConcrete
Ifconcreteisplacedonearth,theearthshouldbemoistened(弄湿)sufficientlytopreventitfromrobbing(夺取)theconcreteofitswater.Iffreshconcreteistobeplacedonoradjacenttoconcretethathasset,thesurfaceoftheoldconcreteshouldbecleanedthoroughly,preferablywithahigh-pressureairandwaterjet(喷射、射流)andsteel-wirebrushes.Thesurfaceshouldbewet,butthereshouldbenostanding(驻留的、静的)water(积水).Asmallquantityofcementgroutshouldbebrushedovertheentirearea,thenfollowedimmediatelywiththeapplicationofa1/2-in.layerofmortar.Thefreshconcreteshouldbeplacedonoragainst(贴着)themortar.
Inordertoreducethesegregation(离析)resultingfrommovementafteritisplaced,concreteshouldbeplacedasnearlyas(在…限度内)practicable(可实行的)initsfinallocation.Itshouldbeplacedinlayerswhosethicknesswillpermitunifor
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