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专业英语课文翻译Lesson4PhrasesandExpressions1.moisturecontent含水量，含湿度;watercontent2.cementpaste水泥浆mortar3.capillarytension毛细管张力，微张力4.gradationofaggregate骨料级配coarsefine(crushedstone,gravel)5.TheBritishCodePC100英国混凝土规范PC100;nowadayBS81106.coefficientofthermalexpansionofconcrete混凝土热膨胀系数7.TheB.SCode英国标准规范8.sustainedload永久荷载，长期荷载9.permanentplasticstrain永久的塑性应变stress10.crystallattice晶格,晶格11.cementgel水泥凝胶体12.water-cementratio水灰比13.expansionjoint伸缩缝14.stabilityofthestructure结构的稳定性structuralstability15.fatiguestrengthofconcrete混凝土的疲劳强度VolumeChangesofConcreteConcreteundergoesvolumechangesduringhardening.混凝土在硬结过程中会经历体积变化。Ifitlosesmoisturebyevaporation,itshrinks,butiftheconcretehardensinwater,itexpands.如果蒸发失去水分，混凝土会收缩；但如果在水中硬结，它便膨胀。Thecausesofthevolumechangesinconcretecanbeattributedtochangesinmoisturecontent,chemicalreactionofthecementwithwater,variationintemperature,andappliedloads.混凝土体积变化的原因可归结为含水量的变化、水泥与水的水化反应、温度变化和所施加的荷载。ShrinkageThechangeinthevolumeofdryingconcreteisnotequaltothevolumeofwaterremoved.Theevaporationoffreewatercauseslittleornoshrinkage.混凝土干燥时的体积变化量不等于它所失去的水的体积。自由水的蒸发基本不产生收缩。Asconcretecontinuestodry,waterevaporatesandthevolumeoftherestrainedcementpastechanges,causingconcretetoshrink,probablyduetothecapillarytensionthatdevelopsinthewaterremaininginconcrete.随着混凝土的不断变干，水分蒸发，受约束水泥浆的体积也变化，导致了混凝土的收缩，这多半是由于残留在混凝土中的水的毛细张力所致。Emptyingofthecapillariescausesalossofwaterwithoutshrinkage.Butoncetheabsorbedwaterisremoved,shrinkageoccurs.毛细管变空导致无收缩的水分丢失，但一旦失去吸收的水分，收缩便发生。Manyfactorsinfluencetheshrinkageofconcretecausedbythevariationsinmoistureconditions.许多因素都会影响因水分环境发生变化而产生的混凝土收缩。1.Cementandwatercontent.Themorecementorwatercontentintheconcretemix,thegreatertheshrinkage.水灰比：水灰比越大，收缩越大；2.Compositionandfinenessofcement.High-early-strengthandlow-heatcementsshowmoreshrinkagethannormalportlandcement.Thefinerthecement,thegreateristheexpansionundermoistconditions.水泥的成分和细度：早强和低热水泥的收缩大于普通水泥，水泥越细，其在潮湿环境中的膨胀越大。3.Type,amount,andgradationofaggregate.Thesmallerthesizeofaggregateparticles,thegreateristheshrinkage.Thegreatertheaggregatecontent,thesmalleristheshrinkage.骨料的类型、含量及其级配：骨料的粒径越小，收缩越大；骨料含量越大，收缩则越小。4.Ambientconditions,moisture,andtemperature.Concretespecimenssubjectedtomoistconditionsundergoanexpansionof200to300×10-6,butiftheyarelefttodryinair,theyshrink.Hightemperaturespeedstheevaporationofwaterand,consequently,increasesshrinkage.外部条件，水分与温度：潮湿环境下的混凝土试件的膨胀量为200to300×10-6，但如果让其在空气中干燥，它们将收缩。高温加速了水分的蒸发，因此也加快了收缩。5.Admixtures.Admixturesthatincreasethewaterrequirementofconcreteincreasetheshrinkagevalue.添加剂：使用水量增加的外加剂也增加了收缩值。6.Sizeandshapeofspecimen.Asshrinkagetakesplaceinareinforcedconcretemember,tensionstressesdevelopintheconcrete,andequalcompressivedevelopinthesteel.Thesestressesareaddedtothosedevelopedbytheloadingaction.Therefore,cracksmaydevelopinconcretewhenahighpercentageofsteelisused.Properdistributionofreinforcement,byproducingbetterdistributionoftensilestressesinconcrete,canreducedifferentialinternalstresses.试件的尺寸和形状：当收缩在钢筋混凝土构件中发生时，混凝土中产生拉应力，同样大小的压力产生于钢筋中，这些力与荷载引起的力相迭加。因此，当钢筋的配筋率高时，可能会使混凝土开裂。钢筋的合理分布、会使混凝土中的拉应力分布更有利，可减小内部应力差。Thevaluesoffinalshrinkageforordinaryconcretevarybetween200and700×10-6.普通混凝土的收缩应变终值在200and700×10-6之间。Fornormal-weightconcrete,avalueof300×10-6maybeused.对常重混凝土，收缩应变终值可取为300×10-6TheBritishCodeCP100givesavalueof500×10-6,whichrepresentsanunrestrainedshrinkageof1.5mmin3mlengthinthin,plainconcretesections.英国CP100规范不出的收缩应变终值为500×10-6，这表示3m长素混凝土薄截面构件的非约束收缩为1.5mm.Ifthememberisrestrained,atensilestressofabout10N/mm2(1400psi)arises.如果此构件受到约束，便产生了大约10N/mm2(1400psi)的拉应力。Ifconcreteiskeptmoistforacertainperiodaftersetting,shrinkageisreduced;如果凝结后将混凝土保持在潮湿环境中，可减小其收缩。therefore,itisimportanttocuretheconcreteforaperiodofnofewerthan7days.因此，将混凝土至少在潮湿环境中养护7天非常重要。Exposureofconcretetowindincreasestheshrinkagerateontheupwindside.将混凝土置于风中将增加其在迎风一侧的收缩速率。Shrinkagecausesanincreaseinthedeflectionofstructuralmembers,whichinturnincreaseswithtime.收缩引起结构构件的挠度增大，而挠度也随时间而增长。Symmetricalreinforcementintheconcretesectionmaypreventcurvatureanddeflectionduetoshrinkage.混凝土截面的对称配筋可防止因收缩而产生的曲率和挠度。Generally,concreteshrinksatahighrateduringtheinitialperiodofhardening,butatlaterstagestheratediminishesgradually.通常，在硬结初期，混凝土收缩较快，但在后期，收缩速度会慢慢变小。Itcanbesaidthat15%to30%oftheshrinkagevalueoccursin2weeks,40%to80%occursin1month,and70%to85%occursin1year.可以说15%to30%收缩量的发生在前两周，40%to80%发生在前一个月，70%to85%发生在第一年。ExpansionDuetoRiseinTemperature升温膨胀Concreteexpandswithincreasingtemperatureandcontractswithdecreasingtemperature.Thecoefficientofthermalexpansionofconcretevariesbetween4and7×10-6perdegreeFahrenheit.混凝土受温膨胀，变冷时收缩。Anaveragevalueof5.5×10-6perdegreeFahrenheit(12×10-6perdegreeCelsius)canbeusedforordinaryconcrete.一般混凝土的平均收缩值为每华氏度5.5×10-6（或每摄氏度12×10-6）。TheB.S.Codesuggestsavalueof10-5perdegreeCelsius.英国标准规范的建议值为每摄氏10-5Thisvaluerepresentsachangeoflengthof10mmina30-mmembersubjectedtoachangeintemperatureof33℃.Ifthememberisrestrainedandunreinforced,astressofabout7N/mm2(1000psi)maydevelop.这一值表示如果30m长的构件温度变化33度，其长度变化为10mm.如果该构件受到约束但并未配筋，由此产生的应力可能约为7N/mm2(1000psi)。Inlongreinforce