土木工程专业英语带译文

Chapter6ReinforcedConcrete

Chapter6整理pptConversation1.—Ourconcretematerialismixedinarotating-drumbatchmixeratthejobsite.

我们用的混凝土是在现场的间歇式转筒搅拌机中搅拌的。2.—Qualityofconcretedependsonproperplacing,finishing,andcuring.

混凝土的质量取决于适当的灌注、抹光和养护。3.—Theworkerstendtostartthefinalfinishingnow.

工人们现在打算开始最后的抹光作业。4.—Theconcretecanbemadestrongerbypre-stressinginourfactory.

在我们厂里可以使混凝土通过预加应力得到增强。Chapter6整理ppt5.—Mostofconstructionmaterialcanbetestedinourlaboratory.我们的实验室可以检验大局部建筑材料。6.—Weshallfinishthecivilworkbytheendoftheyear.在年底前我们将完成土建工作。—Cementsteelandtimberarethemostimportantconstructionmaterialsusedincivilengineering.水泥、钢材和木材是土建工程中最重要的建筑材料。7.Thesearetheanchorbolts(rivets,unfinishedbolts,high-strengthstructuralbolts)forthestructure.这是用于结构的锚定螺栓〔铆钉、粗制螺栓、高强度结构用螺栓〕。整理ppt8.Theholesofanchorboltswillbegroutedwithnormal(Portland,non-shrinkage)cementmortar.这些地脚螺孔将灌入普通〔波特兰，无收缩〕水泥砂浆。9.Weusuallymeasurethestrengthofconcreteat28daysafterwhichhasbeencast.我们通常在混凝土灌注后28天测定其强度。10.Theaveragecompressivestrengthofsamplesis500kg/cm2.试样的平均抗压强度为500公斤/平方厘米Chapter6整理pptTextReinforcedconcreteisconcreteinwhichreinforcementbars(“rebars〞)〔钢筋〕,reinforcementgrids〔钢筋网〕,platesorfibershavebeenincorporatedtostrengthentheconcreteintension.ItwasinventedbyFrenchgardenerJosephMonierin1849andpatentedin1867.ThetermFerroConcreterefersonlytoconcretethatisreinforcedwithironorsteel.钢筋混凝土是由混凝土，钢筋〔钢筋〕，钢筋网〔钢筋网〕，钢板网，钢板或纤维组成，这些被用来加强混凝土的张力。它由法国园丁约瑟夫·莫尼尔于1849年创造，并于1867年获得专利。混凝土仅指用钢或钢加固的混凝土。Chapter6整理pptOthermaterialsusedtoreinforceconcretecanbeorganicandinorganicfibresaswellascompositesindifferentforms.Concreteisstrongincompression,butweakintension,thusaddingreinforcementincreasesthestrengthintension.Inaddition,thefailurestrainofconcreteintensionissolowthatthereinforcementhastoholdthecrackedsectionstogether.Forastrong,ductileanddurableconstructionthereinforcementshallhavethefollowingproperties:其他用于加固混凝土的材料可以是有机和无机纤维以及不同形式的复合材料。混凝土压缩强度大，但抗拉性弱，因此参加钢筋可增加抗拉强度。另外，混凝土的拉伸破坏应变很小，依靠钢筋拉力来控制裂缝。对于巩固，延展性和耐用的结构，钢筋应具有以下特性：整理pptHighstrength高强度Hightensilestrain高拉伸应变Goodbondtotheconcrete与混凝土结合良好Thermalcompatibility热兼容性Durabilityintheconcreteenvironment在具体环境中的耐久性Chapter6整理pptInmostcasesreinforcedconcreteusessteelrebarsthathavebeeninsertedtoaddstrength.在大多数情况下，钢筋混凝土采用钢筋参加以增加强度。UseinconstructionConcreteisreinforcedtogiveitextratensilestrength;withoutreinforcement,manyconcretebuildingswouldnothavebeenpossible.增强混凝土的抗拉强度;没有钢筋水泥，许多混凝土建筑物将不可能实现。整理pptReinforcedconcretecanencompassmanytypesofstructuresandcomponents,includingslabs,walls,beams,columns,foundations,framesandmore.钢筋混凝土可以包括许多类型的结构和构件，包括平板，墙，梁，立柱，根底，框架等等。Reinforcedconcretecanbeclassifiedasprecastorcastin-situconcrete.钢筋混凝土可以分为预制或现浇混凝土。整理pptMuchofthefocusonreinforcingconcreteisplacedonfloorsystems.Designingandimplementingthemostefficientfloorsystemisakeytocreatingoptimalbuildingstructures.Smallchangesinthedesignofafloorsystemcanhavesignificantimpactonmaterialcosts,constructionschedule,ultimatestrength,operatingcosts,occupancylevelsandenduseofabuilding.大局部建筑注重加强混凝土的地板系统。设计和实施最高效的地板系统是创立最正确建筑结构的关键。地板系统设计的微小变化会对建筑物的材料本钱，施工进度，最终强度，运营本钱，入住率和最终用途产生重大影响。整理pptBehavior〔性能〕ofreinforcedconcreteMaterialsConcreteisamixtureofofCoarse(stoneorbrickchips)andFine(generallysand)aggregateswithabindermaterial(usuallyPortlandcement).Whenmixedwithasmallamountofwater,thecementhydratesformmicroscopicopaquecrystallatticesencapsulatingandlockingtheaggregateintoarigidstructure.混凝土是粗粒〔石块或砖块〕和细粒〔通常是沙粒〕与粘结材料〔通常是波特兰水泥〕的混合物。当与少量水混合时，水泥水合物形成微观不透明晶格，将聚集体封装并锁定在刚性结构中。Chapter6整理pptTypicalconcretemixeshavehighresistancetocompressivestresses(about4,000

psi(28

MPa));however,anyappreciabletension(e.g.,duetobending)willbreakthemicroscopicrigidlattice,resultingincrackingandseparationoftheconcrete.Forthisreason,typicalnon-reinforcedconcretemustbewellsupportedtopreventthedevelopmentoftension.典型的混凝土混合料对压缩应力具有很高的抵抗力〔约4,000psi〔28MPa〕〕;然而，任何可观的张力〔例如由于弯曲〕都会破坏微观的刚性格子，导致混凝土开裂和别离。出于这个原因，典型的无筋混凝土必须被很好地支撑以防止张力的开展。整理pptIfamaterialwithhighstrengthintension,suchassteel,isplacedinconcrete,thenthecompositematerial,reinforcedconcrete,resistsnotonlycompressionbutalsobendingandotherdirecttensileactions.Areinforcedconcretesectionwheretheconcreteresiststhecompressionandsteelresiststhetensioncanbemadeintoalmostanyshapeandsizefortheconstructionindustry.如果钢筋等高强度的材料置于混凝土中，那么复合材料钢筋混凝土不仅能抵抗压缩，还能抵抗弯曲和其他直接拉伸作用。钢筋混凝土局部的混凝土抗压缩和钢筋抗张力可以制成几乎任何形状和大小的建筑构件。Chapter6整理pptKeycharacteristicsThreephysicalcharacteristicsgivereinforcedconcreteitsspecialproperties.三种物理特性赋予钢筋混凝土其特殊性能。First,thecoefficientofthermalexpansionofconcreteissimilartothatofsteel,eliminatinglargeinternalstressesduetodifferencesinthermalexpansionorcontraction.首先，混凝土的热膨胀系数与钢相似，消除了由于热膨胀或收缩差异而产生的巨大内部应力。整理pptSecond,whenthecementpastewithintheconcretehardensthisconformstothesurfacedetailsofthesteel,permittinganystresstobetransmittedefficientlybetweenthedifferentmaterials.Usuallysteelbarsareroughenedorcorrugatedtofurtherimprovethebondorcohesionbetweentheconcreteandsteel.其次，当混凝土内的水泥浆硬化时，钢筋外表的构造，可以在不同材料之间有效地传递任何应力。钢筋通常是粗糙的或波纹状的，以进一步改善混凝土和钢之间的粘结或内聚力。Chapter6整理ppt整理pptThird,thealkaline〔碱性的〕chemicalenvironmentprovidedbythealkalireserve(KOH,NaOH)andtheportlandite(calciumhydroxide)containedinthehardenedcementpastecausesapassivatingfilmtoformonthesurfaceofthesteel,makingitmuchmoreresistanttocorrosionthanitwouldbeinneutraloracidicconditions。第三，硬化水泥浆中含有的碱性物质〔KOH，NaOH〕和氢氧化钙〔氢氧化钙〕提供的碱性〔碱性的〕化学环境会在钢的外表形成钝化膜，比在中性或酸性条件下更耐腐蚀Chapter6整理ppt.WhenthecementpasteexposedtotheairandmeteoricwaterreactswiththeatmosphericCO2,portlanditeandtheCalciumSilicateHydrate(CSH)〔水化硅酸钙〕ofthehardenedcementpastebecomeprogressivelycarbonatedandthehighpHgraduallydecreasesfrom13.5–12.5to8.5,thepHofwaterinequilibriumwithcalcite(calciumcarbonate)andthesteelisnolongerpassivated.当暴露于大气中的水泥浆与大气中的二氧化碳发生反响时，硬化水泥浆体的硅酸钙水化硅酸钙〔CSH〕逐渐碳化，高pH值从13.5〜12.5至8.5，与方解石〔碳酸钙〕的水的pH平衡并且钢也不再钝化。整理pptAsaruleofthumb,onlytogiveanideaonordersofmagnitude,steelisprotectedatpHabove~11butstartstocorrodebelow~10dependingonsteelcharacteristicsandlocalphysico-chemicalconditionswhenconcretebecomescarbonated.Carbonationofconcretealongwithchlorideingressareamongthechiefreasonsforthefailureofreinforcementbarsinconcrete.作为一个经验法那么，只有在数量级上给出一个说法，钢在pH值高于〜11时受到保护，但在混凝土碳化时取决于钢的特性和局部物理化学条件而开始腐蚀到10以下。混凝土碳化和氯化物侵入是混凝土中是钢筋破坏的主要原因。Chapter6整理pptTherelativecross-sectionalareaofsteelrequiredfortypicalreinforcedconcreteisusuallyquitesmallandvariesfrom1%formostbeamsandslabsto6%forsomecolumns.Reinforcingbarsarenormallyroundincross-sectionandvaryindiameter.Reinforcedconcretestructuressometimeshaveprovisionssuchasventilatedhollowcorestocontroltheirmoisture&humidity.典型钢筋混凝土所需钢材的相对横截面积通常很小，大多数钢筋混凝土板的1％和某些钢柱的6％不等。钢筋通常横截面为圆形，直径不等。钢筋混凝土结构有时会提供诸如通风中空芯以控制其湿度和湿度。整理pptReinforcementandterminologyofBeams梁的加固和术语Abeambendsunderbendingmoment〔弯矩〕,resultinginasmallcurvature.Attheouterface(tensileface)ofthecurvaturetheconcreteexperiencestensilestress,whileattheinnerface(compressiveface)itexperiencescompressivestress.梁在弯矩〔弯矩〕下弯曲，导致小曲率。在曲率的外外表〔拉伸面〕，混凝土经受拉应力，而在内外表〔压应面〕那么经受压应力。Asingly-reinforcedbeamisoneinwhichtheconcreteelementisonlyreinforcednearthetensilefaceandthereinforcement,calledtensionsteel,isdesignedtoresistthetension.单筋梁是其中混凝土构件仅在拉伸面附近被增强的梁，并且被称为拉伸钢的增强件被设计为抵抗张力。Chapter6整理pptAdoubly-reinforcedbeamisoneinwhichbesidesthetensilereinforcementtheconcreteelementisalsoreinforcednearthecompressivefacetohelptheconcreteresistcompression.Thelatterreinforcementiscalledcompressionsteel.WhenthecompressionzoneofaconcreteisinadequatetoresistthecompressiveMomentpositivemoment),extrareinforcementhastobeprovidedifthearchitectlimitsthedimensionsofthesection.双筋梁是除了抗拉钢筋之外还在靠近压缩面处加强混凝土元件以帮助混凝土抵抗压缩的梁。后一种钢筋称为压缩钢筋。当混凝土的压缩区域缺乏以抵抗压缩力矩正向力矩时〕，如果建筑师限制该局部的尺寸，那么必须提供额外的加固。整理pptAnunder-reinforcedbeamisoneinwhichthetensioncapacityofthetensilereinforcementissmallerthanthecombinedcompressioncapacityoftheconcreteandthecompressionsteel(under-reinforcedattensileface).Whenthereinforcedconcreteelementissubjecttoincreasingbendingmoment,thetensionsteelyields，whiletheconcretedoesnotreachitsultimatefailurecondition.Asthetensionsteelyieldsandstretches,an“under-reinforced〞concretealsoyieldsinaductilemanner,exhibitingalargedeformationandwarningbeforeitsultimatefailure.Inthiscasetheyieldstressofthesteelgovernsthedesign.少筋梁是其中拉伸钢筋的拉伸能力小于混凝土和压缩钢的组合压缩能力〔在拉伸面处欠加固〕的梁。当钢筋混凝土构件受弯矩增加时，钢筋屈服，而混凝土未到达其最终破坏状态。随着拉伸钢的屈服和拉伸，“欠加固〞的混凝土也会以延性方式屈服，在最终失效之前表现出较大的变形。在这种情况下，钢的屈服应力决定了设计。Chapter6整理pptAnover-reinforcedbeamisoneinwhichthetensioncapacityofthetensionsteelisgreaterthanthecombinedcompressioncapacityoftheconcreteandthecompressionsteel(over-reinforcedattensileface).Sothe“over-reinforcedconcrete〞beamfailsbycrushingofthecompressive-zoneconcreteandbeforethetensionzonesteelyields,whichdoesnotprovideanywarningbeforefailureasthefailureisinstantaneous.超筋梁是其中拉伸钢的拉伸能力大于混凝土和压缩钢的组合压缩能力〔在拉伸面处过度增强〕的梁。因此，“过度加强的混凝土〞梁通过压缩区混凝土的破碎而失效，并且在张拉区钢材屈服之前不会发出任何警告，因为失效是瞬时的。整理pptAbalanced-reinforcedbeamisoneinwhichboththecompressiveandtensilezonesreachyieldingatthesameimposedloadonthebeam,andtheconcretewillcrushandthetensilesteelwillyieldatthesametime.Thisdesigncriterionishoweverasriskyasover-reinforcedconcrete,becausefailureissuddenastheconcretecrushesatthesametimeofthetensilesteelyields,whichgivesaverylittlewarningofdistressintensionfailure..适筋梁是在梁上相同的施加载荷下，压缩区和拉伸区都到达屈服的，并且混凝土将被压扁并且拉伸钢将同时屈服。然而，这种设计标准与过度加固的混凝土一样危险，因为在拉伸钢筋屈服的同时混凝土破坏会导致破坏突然发生，这在拉伸破坏时几乎没有发生危险的警告。Chapter6整理pptSteel-reinforcedconcretemoment-carrying(弯矩承载)elementsshouldnormallybedesignedtobeunder-reinforcedsothatusersofthestructurewillreceivewarningofimpendingcollapse.Thecharacteristicstrengthisthestrengthofamaterialwherelessthan5%ofthespecimenshowslowerstrength。钢筋混凝土受弯构件通常应设计为不超筋，以便结构使用者能够收到即将崩塌的警告。特征强度是一种材料的强度，其中少于5％的试样表现出较低的强度。整理pptThedesignstrengthornominalstrengthisthestrengthofamaterial,includingamaterial-safetyfactor.Thevalueofthesafetyfactorgenerallyrangesfrom0.75to0.85inAllowableStressDesign.设计强度或名义强度是材料的强度，包括材料平安系数。允许应力设计中的平安系数值通常在0.75至0.85之间。Theultimatelimitstateisthetheoreticalfailurepointwithacertainprobability.Itisstatedunderfactoredloadsandfactoredresistances.极限状态是具有一定概率的理论失效点。它是在分解载荷和因素阻力下陈述的。Chapter6整理pptCommonfailuremodesofsteelreinforcedconcrete钢筋混凝土的常见破坏模式Reinforcedconcretecanfailduetoinadequatestrength,leadingtomechanicalfailure,orduetoareductioninitsdurability.Corrosionandfreeze/thawcyclesmaydamagepoorlydesignedorconstructedreinforcedconcrete.Whenrebarcorrodes,theoxidationproducts(rust)expandandtendstoflake,crackingtheconcreteandunbondingtherebarfromtheconcrete.Typicalmechanismsleadingtodurabilityproblemsarediscussedbelow.由于强度缺乏，钢筋混凝土可能会失效，导致机械故障或耐久性降低。腐蚀和冻结/解冻循环可能会损坏设计不合理的钢筋混凝土。当钢筋受到腐蚀时，氧化产物〔铁锈〕膨胀并趋于剥落，使混凝土开裂并使钢筋与混凝土脱开。下面讨论导致耐久性问题的典型机制。整理pptMechanicalfailureCrackingoftheconcretesectioncannotbeprevented;however,thesizeofandlocationofthecrackscanbelimitedandcontrolledbyreinforcement,placementofcontroljoints,thecuringmethodologyandthemixdesignoftheconcrete.Crackingdefectscanallowmoisturetopenetrateandcorrodethereinforcement.Thisisaserviceabilityfailureinlimitstatedesign.Crackingisnormallytheresultofaninadequatequantityofrebar,orrebarspacedattoogreatadistance.Theconcretethencrackseitherunderexcessloadingorduetointernaleffectssuchasearlythermalshrinkagewhenitcures.混凝土局部的开裂是无法防止的;然而，裂缝的大小和位置可以通过加固，控制缝的位置，固化方法和混凝土的混合设计来限制和控制。开裂缺陷可能使水分渗透并腐蚀钢筋。这是极限状态设计中的可维护性故障。裂纹通常是由于螺纹钢数量缺乏或钢筋间距太大而造成的。混凝土随后会在过载或由于内部影响〔如固化时的早期热收缩〕而破裂。Chapter6整理pptUltimatefailureleadingtocollapsecanbecausedbycrushingoftheconcrete,whencompressivestressesexceeditsstrength;byyieldingorfailureoftherebar,whenbendingorshearstressesexceedthestrengthofthereinforcement;orbybondfailurebetweentheconcreteandtherebar.当压缩应力超过其强度时，导致混凝土破碎的最终失效可能是由混凝土的破碎引起的;通过屈服或失败的钢筋，当弯曲或剪切应力超过钢筋的强度时;或混凝土和钢筋之间的粘结失败。整理pptCarbonationCarbonation,orneutralisation,isachemicalreactionbetweencarbondioxideintheairwithcalciumhydroxideandhydratedcalciumsilicateintheconcrete.ThewaterintheporesofPortlandcementconcreteisnormallyalkalinewithapHintherangeof12.5to13.5.Thishighlyalkalineenvironmentisoneinwhichtheembeddedsteelispassivatedandisprotectedfromcorrosion.AccordingtothePourbaixdiagramforiron,themetalispassivewhenthepHisabove9.5.碳化或中和是空气中的二氧化碳与混凝土中的氢氧化钙和水合硅酸钙之间的化学反响。波特兰水泥混凝土孔隙中的水通常是碱性的，其pH值范围为12.5至13.5。这种高度碱性的环境是嵌入钢钝化并防腐蚀的环境。根据铁的普贝图，当pH高于9.5时，金属是不会被腐蚀的Chapter6整理pptThecarbondioxideintheairreactswiththealkaliinthecementandmakestheporewatermoreacidic,thusloweringthepH.Carbondioxidewillstarttocarbonatethecementintheconcretefromthemomenttheobjectismade.Thiscarbonationprocesswillstartatthesurface,thenslowlymovedeeperanddeeperintotheconcrete.Therateofcarbonationisdependentontherelativehumidityoftheconcrete-a50%relativehumiditybeingoptimal.Iftheobjectiscracked,thecarbondioxideintheairwillbebetterabletopenetrateintotheconcrete.空气中的二氧化碳与水泥中的碱反响，使孔隙水变酸，从而降低pH值。二氧化碳将开始使混凝土中的水泥发生碳酸盐化。这种碳酸化过程将从外表开始，然后慢慢地向混凝土深入。碳化速度取决于混凝土的相对湿度-50％的相对湿度是最正确的。如果物体破裂，空气中的二氧化碳会更好地渗透到混凝土中。整理pptWhendesigningaconcretestructure,itisnormaltostatetheconcretecoverfortherebar(thedepthwithintheobjectthattherebarwillbe).Theminimumconcretecoverisnormallyregulatedbydesignorbuildingcodes.Ifthereinforcementistooclosetothesurface,earlyfailureduetocorrosionmayoccur.Theconcretecoverdepthcanbemeasuredwithacovermeter.However,carbonatedconcreteonlybecomesadurabilityproblemwhenthereisalsosufficientmoistureandoxygentocauseelectro-potentialcorrosionofthereinforcingsteel.在设计混凝土结构时，说明钢筋的混凝土保护层〔钢筋的物体内部的深度〕是正常的。最小混凝土保护层通常由设计或建筑标准进行确定。如果钢筋太靠近外表，可能会发生由腐蚀引起的早期失效。具体的保护层深度可以用测量仪来测量。然而，碳化混凝土只有在有足够的湿气和氧气引起钢筋的电位腐蚀时才会变成耐久性问题。整理pptOnemethodoftestingastructureforcarbonationistodrillafreshholeinthesurfaceandthentreatthecutsurfacewithphenolphthaleinindicatorsolution.Thissolutionwillturn[pink]whenincontactwithalkalineconcrete,makingitpossibletoseethedepthofcarbonation.Anexistingholeisnogoodbecausetheexposedsurfacewillalreadybecarbonated.测试碳化结构的一种方法是在外表钻一个新的孔，然后用酚酞指示剂溶液处理切割外表。与碱性混凝土接触时，该解决方案会变成粉红色，从而可以看到碳酸化深度。现有的孔不好，因为暴露的外表已经被碳酸化了。

Chapter6整理pptChlorides氯化物Chlorides,includingsodiumchloride,canpromotethecorrosionofembeddedsteelrebarifpresentinsufficientlyhighconcentration.Chlorideanionsinducebothlocalizedcorrosion(pittingcorrosion)andgeneralizedcorrosionofsteelreinforcements.Forthisreason,oneshouldonlyusefreshrawwaterorpotablewaterformixingconcrete,insurethatthecoarseandfineaggregatesdonotcontainchlorides,andnotuseadmixturesthatcontainchlorides.氯化物〔包括氯化钠〕可以促进嵌入式钢筋的腐蚀，如果其含量足够高。氯阴离子引起局部腐蚀〔点腐蚀〕和钢筋腐蚀。出于这个原因，应该只使用新鲜的原水或饮用水来搅拌混凝土，确保粗骨料和细骨料不含氯化物，不使用含氯化物的外加剂。整理pptItwasoncecommonforcalciumchloridetobeusedasanadmixturetopromoterapidset-upoftheconcrete.Itwasalsomistakenlybelievedthatitwouldpreventfreezing.However,thispracticehasfallenintodisfavoroncethedeleteriouseffectsofchloridesbecameknown.Itshouldbeavoidedwheneverpossible.氯化钙曾经作为混合物来促进混凝土的快速成型，这是很常见的。它也被误认为会防止冻结。然而，一旦氯化物的有害影响变得，这种做法就变得不受欢送。应尽可能防止。Chapter6整理pptTheuseofde-icingsaltsonroadways,usedtoreducethefreezingpointofwater,isprobablyoneoftheprimarycausesofprematurefailureofreinforcedorprestressedconcretebridgedecks,roadways,andparkinggarages.Theuseofepoxy-coatedreinforcingbarsandtheapplicationofcathodicprotectionhasmitigatedthisproblemtosomeextent.AlsoFRPrebarsareknowntobelesssusceptibletochlorides.Properlydesignedconcretemixturesthathavebeenallowedtocureproperlyareeffectivelyimpervioustotheeffectsofdeicers.在道路上使用除冰盐〔用于降低水的冰点〕可能是钢筋或预应力混凝土桥面，道路和停车库过早失效的主要原因之一。使用环氧涂层钢筋和阴极保护的应用已经在一定程度上缓解了这个问题。纤维增强复合材料不易受氯化物影响。正确设计的混凝土混合物已被正确固化，可有效地抵抗除冰器的影响。整理pptAnotherimportantsourceofchlorideionsisfromseawater.Seawatercontainsbyweightapproximately3.5

wt.%salts.Thesesaltsincludesodiumchloride,magnesiumsulfate(硫酸镁),calciumsulfate(硫酸钙),andbicarbonates.Inwaterthesesaltsdissociateinfreeions(Na+,Mg2+,Cl-,SO42-,HCO3-)andmigratewiththewaterintothecapillariesoftheconcrete.Chlorideionsareparticularlyaggressiveforthecorrosionofthecarbonsteelreinforcementbarsandmakeupabout50%oftheseions.氯离子的另一个重要来源是海水。海水含有约3.5％的盐。这些盐包括氯化钠，硫酸镁〔硫酸镁〕，硫酸钙〔硫酸钙〕和碳酸氢盐。在水中，这些盐在游离离子〔Na+，Mg2+，Cl-，SO42-，HCO3-〕中解离并随水迁移到混凝土的毛细管中。氯离子对碳钢钢筋的腐蚀特别具有侵蚀性，占这些离子的约50％。Chapter6整理pptInthe1960’sand1970’sitwasalsorelativelycommonforMagnesite,achloriderichcarbonatemineral,tobeusedasafloor-toppingmaterial.Thiswasdoneprincipallyasalevellingandsoundattenuatinglayer.Howeveritisnowknownthatwhenthesematerialscameintocontactwithmoistureitproducedaweaksolutionofhydrochloricacidduetothepresenceofchloridesinthemagnesite.Overaperiodoftime(typicallydecades)thesolutioncausedcorrosionoftheembeddedsteelrebars.Thiswasmostcommonlyfoundinwetareasorareasrepeatedlyexposedtomoisture.在二十世纪六十年代和七十年代，菱镁矿是一种富含氯化物的碳酸盐矿物，也被用作地面浇筑材料。这主要是作为整平和消音层完成的。然而，现在当这些材料与水分接触时，由于氯化镁存在于菱镁矿中，所以它产生了盐酸的弱溶液。经过一段时间〔通常为数十年〕，该解决方案导致嵌入式钢筋锈蚀。这是最常见的潮湿地区或反复暴露于潮湿的地区。整理pptWordsandExpressionplate [pleit] n.盘子，盆子;

金属板fiber ['faibə] n.光纤;

纤维，纤维物patent ['pætnt] n.专利;

专利品;

专利权composite ['kɒmpəzit] adj.混合成的，综合成的;

ductile ['dʌktail] adj.可延展的;

有韧性的coarse [kɔ:s] adj.粗俗的;

粗糙的;

粗野的hydrate ['haidreit] n.水合物;

lattice ['lætis] n.格子框架Chapter6整理pptroughen ['rʌfn] v〔使〕变得粗糙，变得不平;

cohesion [kəʊ‘hi:ʒn] n.凝聚，内聚;

〔各部的〕结合portlandite ['pɔ:tlɔndait] n.氢氧钙石;

羟钙石;

neutral ['nju:trəl] adj.中立的;

〔化学中〕中性的meteoric ['mi:tiɔrik] adj.疾速的;

令人眼花缭乱的equilibrium [ˌi:kwi'libriəm] n.均衡；平静magnitude ['mægnitju:d] n.大小；量级;光度ingress ['inɡres] n.进入；入口；准许进入；入境curvature ['kə:vətʃə(r)]] n.弯曲，[数]曲率整理pptdistress [di'stres] n.危难，不幸；贫困；悲哀impend [im'pend] v.迫近；悬空〔impend的现在分词〕specimen ['spesimən] n.样品，样本；标本factoredload n.乘上系数的荷载，设计极限荷载factoredresistance n.考虑阻力thaw [θɔ:] n.解冻；融雪v.使融解；使变得不拘束penetrate ['penətreit] v渗透；刺入；看透serviceability [sə:visə'biliti] n.可用性，适用性shear [ʃiə(r)] n.[力]切变；修剪；大剪刀v.剪；剪切；修剪Chapter6整理pptpore [pɔ:(r)]n.气孔；小孔v.使注视humidity [hju:'midəti]n.[气象]湿度；湿气optimal ['ɔptiməl]adj.最正确的；最理想的drill [dril]n.训练；钻孔机；钻子；播种机v.钻孔；训练；条播phenolphthalein [ˌfi:nil'fθæli:n]n.[试剂]酚酞〔一种测试碱性的试剂，可作刺激性泻剂〕chloride ['klɔ:raid]n.氯化物anion ['ænaiən]n.阴离子deleterious [ˌdelə'tiəriəs]adj.有毒的，有害的Chapter6整理pptepoxy-coated [e'pɔksi-'kəʊtid]n.环氧涂层cathodic [kə'θɔdik]adj.阴极的；负极的susceptible [sə‘septəbl]adj.易受影响的；易感动的；容许…的impervious [im'pə:viəs]adj.不受影响的，无动于衷的；不能渗透的bicarbonate[bai'k:bənət]n.碳酸氢盐；重碳酸盐；酸式碳酸盐dissociate[d'set]v.游离；使别离；分裂capillary[kə'piləri]n.毛细管adj.毛细管的；毛状的magnesite['mægnəsait]n.[矿物]菱镁矿attenuat