混凝土專業(yè)畢業(yè)設(shè)計外文翻譯混合物配合比設(shè)計

附錄外文翻譯MIXDESIGN&PROPORTIONING（一）MIXDESIGNTheconcretemixdesign(CMD)forQC/QAsuperstructureconcretemustproduceaworkableconcretemixturehavingpropertiesthatwillnotexceedthemaximumand/orminimumvaluesdefinedinthespecialprovision.Workabilityinconcretedefinesitscapacitytobeplaced,consolidated,andfinishedwithoutharmfulsegregationorbleeding.Workabilityisaffectedbyaggregategradation,particleshape,proportioningofaggregate,amountandqualitiesofcementitiousmaterials,presenceofentrainedair,amountandqualityofhighrangewaterreducer,andconsistencyofmixture.Consistencyoftheconcretemixtureisitsrelativemobilityandismeasuredintermsofslump.Thehighertheslumpthemoremobiletheconcrete,affectingtheeasewithwhichtheconcretewillflowduringplacement.Consistencyisnotsynonymouswithworkability.Twodifferentmixdesignsmayhavethesameslump;however,theirworkabilitymaybedifferent.Selectionoftargetparametersbythecontractorforanymixdesignmustconsidertheinfluenceofthefollowing:1.materialavailabilityandeconomics2.variabilityofeachmaterialthroughoutperiodofusage3.controlcapabilityofproductionplant4.ambientconditionsexpectedatthetime(s)ofconcreteplacement5.logisticsofconcreteproduction,delivery,andplacement6.variabilityintestingconcreteproperties7.generationofheatinlargestructuralelementsanddifferentialinthermalgradientThequalitiesofthecementitiouspasteprovideaprimaryinfluenceonthepropertiesofconcrete.Properselectionofthecementitiouscontentandwater/cementitiousratioisdependentontheexperienceoftheconcreteproducerandbecomesaveryimportantfirststepinpreparingadesign.Forworkableconcrete,ahigherwatercementitiousratioistypicallyrequiredwhenaggregatebecomesmoreangularandroughtextured.Thepresenceofair,certainpozzolans,andaggregateproportioningwillworktolowerthewatercementitiousratio;howeverthemostsignificantreductioninwaterdemandcomesthroughtheuseofahighrangewaterreducingchemicaladmixture.Water/cementitiousratioisdeterminedfromthenet,perunit,quantityofwaterandtotalcementitiousmaterials.Thenetwatercontentexcludeswaterthatisabsorbedbytheaggregates.Foragivensetofmaterialsandconditions,aswater/cementitiousratioincreases,strengthandunitweightwilldecrease.Compressivestrengthisaconcreteparameterusedincombinationwithunitweightandaircontenttoevaluatethedurabilityofthesuperstructureconcrete'sexposuretofreeze/thawaction,andexposuretodeicingsalts.Itisimportanttonotethatthedesignerofthebridgestructuredoesnotrecognizethebenefitofincreasedcompressivestrength.Theslabstillreliesonaminimumdesigncompressivestrength(f'c)of4000psiat28-days.Proportioningofaggregatesisdefinedbythevolumeoffineaggregatetothevolumeofcoarseaggregate,asapercent.Thelowerpercentageoffinetototalaggregateprovidesanincreaseincompressivestrengthattheexpenseofworkability.Thegradation,particleshapeandtextureofthecoarseaggregatealongwithfinenessmodulusofthefineaggregatewilldeterminehowlowthefinetototalaggregatepercentagecanbeforagivenworkabilityrequirement.（二）MIXINGPROPORTIONINGOncethecementcontent,pozzolancontent,water/cementitiousratio,andfinetototalaggregatepercentagearedefinedfortheconcrete'sintendeduseinthesuperstructure,proportioningofthemixintermsofdesignbatchweightscanbegin.Specificgravitiesmustbeaccuratelydefinedforeachmaterialbeingutilizedinordertoproportionthemixproperlybytheabsolutevolumemethod.Cementistypicallyacceptedashavingaspecificgravityof3.15.Pozzolanswilltypicallyvarybetween2.22and2.77.Pozzolansuppliersshouldreadilybeabletoprovidecurrentvaluesfortheirmaterial.ApproximatespecificgravitiesareidentifiedforeachsourceontheDepartment'sApproved/PrequalifiedMaterialslist;however,theyshouldnotbeconsideredthemostcurrent.Bulkspecificgravity,inthesaturatedsurfacedrycondition,mustbeusedtoproportionthefineandcoarseaggregate.AccuratetestingofoneormoresamplesoffineandcoarseaggregatemustbeaccomplishedbytheContractoraspartofanyproportioningforamixdesign.Subsequentshiftsinbenchingattheaggregatesourcemaycausesignificantshiftsinbulkspecificgravityandabsorption.Theseareimportantaggregatepropertiestomonitoraspartofconcretequalitycontrol.Proportioningconcretebytheabsolutevolumemethodinvolvescalculatingthevolumeofeachingredientanditscontributiontomakingoneyd3or27ft3ofconcrete.Volumesaresubsequentlyconvertedtodesignweights,whichthenbecomethebasisforactualproductionofconcretefromtheplant.Forcementitiousmaterialsandwater,theweighttovolumeconversionisaccomplishedbydividingtheweight(lbs)bythespecificgravityofthematerialandagaindividingbythedensityofwater.Convertingfromvolumetoweightisaccomplishedsimplybytakingtheknownvolumeoftheingredientandmultiplyingbythespecificgravityoftheingredientandagainmultiplyingbythedensityofwater.Volumetoweightconversionsforaggregatesareaccomplishedbythesameseriesofcomputations;however,bulkspecificgravity(SSD)mustbeused.Thetargetaircontentisestablishedat6.5%bythespecialprovision,whichconvertstoavolumeof1.76f（三）LINEAREQUATIONOFUNITWEIGHTvs.AIRCONTENTItisknownthattheunitweightofplasticconcreteisinverselyproportionaltoaircontent.Thatistosay,asaircontentincreasesunitweightdecreases.Thisrelationshipbecomesaveryusefultoolwhenevaluatingplasticconcrete.Unitweightandaircontentarepropertiesofplasticconcretethatcanbeeasilyandquicklymeasuredinthefield.Aunitweightmeasurement,ataknownaircontent,thatdeviatesexcessivelyfromthelinearrelationshipprovidesinformationastothepossibledeficienciesinthemixandpotentialeffectsonpropertiessuchasworkability,durability,andstrength.Thelinearequationtopredictunitweightbasedonagivenaircontentispresentedbelowindirectionalform:UW=m(Air)+bWhere:mistheslopeoflineAiristheplasticconcreteaircontent(independentvariable,xcoordinateorabscissaofpoint)bisthey-interceptUWistheplasticconcreteunitweight(dependentvariable,ycoordinate,orordinateofpoint)Ifallpoints(Air,UW)associatedwiththesolutionsetofthislinearequationwereplottedonagraph,therewouldbeastraightlineasillustratedbyFigure3.1.Thislinearrelationshipcanbedeterminedforanyconcretemixdesign.（四）THRESHOLDFORMAXIMUMALLOWABLEWATER/CEMENTITIOUSRATIOJustasconcreteunitweightisaffectedbychangesinaircontent,itisalsoaffectedbytheamountofwaterthatisavailabletoreactwithcementitiousmaterials.Astheamountofwaterincreasesthewater/cementitiousratioalsoincreases,producingconcreteofinferiorquality.Thisservestolowertheconcreteunitweightatanygivenaircontent.Sincethemaximumallowablewater/cementitiousratioforQC/QAsuperstructureconcreteis0.420,athresholdlineorlimitcanbedetermined.Thisthresholdlinewouldbeparalleltothelinearequationforthemixdesign;however,theunitweightwouldbelower.ThethresholdlimithasrelevancytoresultsfromqualitycontrolaswellasAcceptancesamplingandtesting.Shouldthemeasuredunitweightatanygivenaircontentbeatorlowerthanthethreshold,itcouldindicatethatthemaximumallowablewatercementitiousratiowasexceeded.Itisimportanttounderstandthatqualitycontrolworkstocenterproductionaboutthelinearequationforthemixdesign.Thereareseveralwaysinwhichadditionalwatercouldenteraconcretemix.Themethodologypresentedinthischapterassumesthattheincreaseinwater/cementitiousratioisduesoleytoexcessivebatchwater.Thisprovidesasimpleandaccuratedeterminationofthethresholdlimitequation.Themethodologybeginswiththelinearequationalreadyestablishedforthemixdesign.Byestablishingasinglepointbelowthelinearequation,representingconcretewithexcessivewater,theequationforthresholdlimitcanbedetermined.Theeasiestpointtoselectisatthey-intercept,wheretheconcretehasnoentrappednorentrainedair.ThispointisdefinedasPoint3,havingcoordinates(x3,y（五）MixDesign&ProportioningWorksheetsIfatleasttwopointsareknowntobeasolutiontotheequation,algebracanbeutilizedtosolveforthetwounknownvariables(i.e.slopeandy-intercept).TheforminAppendixD(undertab11)entitled"WORKSHEETFORCMDLINEAREQUATION"providestheformatinwhichtwopointscanbedefinedandtheequationdetermined.TheCartesiancoordinatesofonesolutionpointisalreadyavailablefromthemixdesign.WecandefinethisasPoint2withcoordinates(x2,y2).Thevalueofx2isthetargetaircontentofthemixdesign(i.e.xabsolutevolumeswhichwillalwaysbe27.00ftExample:xyy2y2AplotofthecoordinatesforPoint2(x2=6.5,yPoint1,representingthey-intercepthavingcoordinates(x1,y1),mustnowbedetermined.Thisisaccomplishedbytheoreticallyremovingalltheentrappedandentrainedairfromthemixtureandcalculatingtheconcreteunitweight.Thevalueofx1is0.0%aircontent.ThevalueofycalculatesthecoordinatesforPoint1.Example:xyyy1TheCartesiancoordinatesofPoint1,(x1=0.0,yItisimportanttorememberthatasairisremovedfromconcretetheindividualweightsofcementitiousmaterials,fineaggregate,coarseaggregate,andwaternolongerrepresentamountsrelativeto1.000yd3ofconcrete.Concretewithoutthe6.5%targetaircontent(1.76ft3)wouldonlyyield0.9348ydFromthexandycoordinatesofPoints1&2,thereisnowenoughinformationtosolveforthevariablesofslopeandy-interceptinthelinearequation.Theworksheetcalculationforslope,alsoknownas"rise/run",isexemplifiedasfollows:Example:m=?Itisimportanttonotethatslopewillalwaysbenegativesinceunitweightisinverselyproportionaltoaircontent.They-interceptvalue(b)issimplytheordinateofPoint1,whichhasalreadybeendetermined.Intheexampleproblem,theworksheetwouldshowthesolutionbasfollows:Example:Thecalculatedandroundedvaluesforslopeandy-interceptcannowbeinsertedinthelinearequationforthevariablesmandb,respectively.Thelinearequationcannowbewrittenfortheconcretemixdesign.Thenumbersfromtheexampleresultinthefollowing:Example:（六）DEPARTMENTCONCURRENCEOFMIXDESIGNItistheresponsibilityoftheDepartment'sProjectEngineer/ProjectSupervisortoconductacompleteandthoroughreviewofeverymixdesignandproportioningforQC/QASuperstructureConcrete.ThereisasubstantialamountofworkthatisbasedonthetargetsestablishedbytheCMD,nottheleastofwhichisthelinearequationforthethresholdlimitthatrepresentsthemaximumallowablewater/cementitiousratio.ThisthresholdlimitisofcriticalimportanceindeterminingwhetheradditionalcylindersaretobecastaspartofanacceptancesamplefortestingperAASHTOT277andsubsequentaction,whichmayinvolveafailedmaterialinvestigation.ThefirststepinproperreviewofaCMDistoverifythatthematerialsarefromcurrentapprovedsources.ThelistofApprovedand/orPrequalifiedMaterialsistobeusedtoverifyapprovedsourcesofcement,flyash,GGBFS,silicafume,chemicaladmixturesandairentrainingagents.ThefineandcoarseaggregateingredientsoftheconcretemixmustbematerialsfromanapprovedCertifiedAggregateProducer.Thegradationandqualityrequirementfortheaggregatesmustalsobeverified,particularlyifstay-in-placemetaldeckformsareusedtofacilitateconstructionofthedeck.IfAPQualitycoarseaggregateisrequiredinthesuperstructure,thePE/PSwillsubstantiatethequalitystatus.Thiswouldincludethenatureoftheminingoperationsthatproduceaggregatesofthedesiredquality.ThePE/PSshouldcontacttheDistrictMaterials&TestsEngineerortheDistrictGeologistforconfirmation.InadditiontotheaggregatesgradationsthePE/PSmustverifythebulkspecificgravity(SSD)andabsorptionforthefineandcoarseaggregateasbeingreasonableforthesource.IftheContractor'svalueforabsorptiondiffersbymorethanthemultilabortoryprecisiondefinedwithintheappropriatetestmethod,thediscrepancywillbeinvestigated.ThebulkspecificgravityandabsorptionforaggregatesaremeasuredbytheDepartmentaspartoftheannual"SummaryofProductionQualityResults",andperiodicPoint-Of-Usesamples.Thisdataprovidesthecorrectbasisforcomparisonofabsorptionandspecificgravity.Figures3.5and3.6aregraphsofbulkspecificgravity(ssd)vs.absorptionforafineandcoarseaggregateandarepresentedasexamplesofwhathistoricaldatamightlooklikeforspecificproductsatanaggregatesource.Usuallysourceswilldemonstrateatrendofbulkspecificgravity(SSD)beinginverselyproportionaltoabsorption;however,suchmaynotalwaysbethecase.Figure3.6representsdatafromtheINDOTSummaryofProductionQualityResultsforaspecificsourceof#8coarseaggregate.TheAPqualitystonecomesfromledges1803,1804,19,&20processedasoneworkingbench.Thesefourledgeshavethicknessesof7.9ft,8.9ft,5.9ft,and12.1ft,respectively.Sincetheseledgesrangeinabsorptionfrom2%to4%,theconsistencyofbulkspecificgravityandabsorptiondependsontheaggregatesource'sabilitytoprocessthebenchinauniformmanner.TheDistrictGeologististhebestsourceforobtaininghistoricaldatafrom"SummaryofProductionQualityResults"and"Point-of-Use"samplesobtainedfromtheaggregatesource.TheywillassistthePE/PSintheproperreviewofcontractortestresultsforaggregates.ItisimportanttounderstandthatINDOThistoricalrecordsforbulkspecificgravity(dryorSSD)fromcoarseaggregatesourcesarebasedonprocedure8.1ofAASHTOT85.TheContractormustthereforetestthecoarseaggregateaccordingtothesameprocedureeventhoughtheresultistypicallynotappropriateforconcretemixdesign.Ifthemixdesignissubmittedwithenoughadvancenotice,itbecomespreferablefortheDepartmenttoobtainaPoint-Of-Usesampleofthecoarseaggregateandtestforbulkspecificgravity(SSD)byprocedure8.2ofAASHTOT85,whichisappropriateforconcretemixdesign.SplittingasamplebetweentheContractorandtheDepartmenttocomparetestresultswouldbeevenbetter.TheairentrainingandchemicaladmixturesthatareapprovedforuseareasstatedinthespecialprovisionandtheApproved/PrequalifiedMaterialsListreferencedtherein.ItisimportanttorecognizethelimitationsofTypeFadmixturesorHRWRAdmixtureSystems.Thesechemicaladmixtureshavenoretardingcapabilityandwouldnotbeappropriateforsuperstructureconcretethatisplacedinconditionswhereconcreteandambienttemperaturesareabove65°F,andwheredeadloaddeflectionsareofconcern.Afterverifyingthematerialsasbeingapprovedfortheconcrete,theinitialparametersfortheMixDesignmustbecheckedagainstthespecificationrequirements.TheremainderofthePE/PScheckinvolvescheckingthemathforproportioning,andthelinearequationsfortheCMDandthresholdlimit.UseoftheformsandworksheetsbythecontractorwillprovidethequickestandmostcompletereviewbytheDepartmentandthereforehelpeliminateunnecessarydelaysbyrecognizingproblemsearlyon.混合物配合比設(shè)計（一）混合物設(shè)計混凝土配合比設(shè)計混凝土質(zhì)量保證上層建筑（CMD）用于QC/QA必須出示有一個和易性好的混凝土混合物的性能，將不會超過最大和/或最低的特別規(guī)定定義的值。在具體的工作性定義它的的能力，放置，鞏固，無離析或泌水?？刹僮餍允鞘芄橇霞壟洌w粒形狀，配料總量，數(shù)量和質(zhì)量的膠凝材料減速氣流，空氣的含量，高效減水劑的數(shù)量和質(zhì)量，及混和料的和易性。混凝土混合物的和易性用相應(yīng)的流動性，和坍落度衡量。坍落度越高，混凝土流動性就越好，對混凝土將流動過程中的具體位置影響更好。和易性和可操作性不等同。兩種不同的配合比設(shè)計可能有相同的坍落度，但其工作性能可能會有所不同。目標參數(shù)的選擇，承包商的任何配合比的設(shè)計必須考慮下面的影響：1.材料供應(yīng)和經(jīng)濟狀況2.在整個使用期間每一種材料的變化3.生產(chǎn)廠的管理能力4.預(yù)期在混凝土澆筑時的環(huán)境條件5.混凝土產(chǎn)品的物流，配送與安置6.在測試中混凝土性能變化7.熱產(chǎn)生在大型構(gòu)件和在熱梯度的差別。水泥粘貼性的質(zhì)量起到了對混凝土主要性能的影響。正確選擇水泥含量和水灰比依賴于生產(chǎn)的經(jīng)驗，準備工作是完成一個非常重要的設(shè)計的第一步。對于和易性好的混凝土，水灰比較高的水時，通常需要更多的角度和總體變得粗糙質(zhì)感的集料?？諝獾拇嬖?，一定的火山灰，集料配料凈漿降低水灰比；然而，最顯著降低用水量求是通過使用一種高化學(xué)減水劑的外加劑。水灰比由每單，水的重量和總膠凝材料重量決定。水凈含量不包括由集料所吸收的水量。對于一個給定的材料和條件，水灰比增大，強度和單位重量將減少?？箟簭姸仁窃趩挝恢亓亢涂諝夂烤唧w的參數(shù)組合使用，以評估暴露結(jié)構(gòu)的耐久性混凝土的凍結(jié)/解凍的行為，以及接觸除冰鹽。重要的是要注意到，在橋梁結(jié)構(gòu)設(shè)計不會增加抗壓強度。該板仍然依賴抗壓強度（f'c）28天最低設(shè)計4000psi。集料配合比是指由細骨料量與粗骨料量，以百分比。損失可工作性下，低比例的集料總額合計使抗壓強度增加。級配，顆粒形狀和質(zhì)地優(yōu)良的總和粗骨料模量隨細度低，將決定如何將集料比例可以為一個給定的可操作性的要求。（二）混合配料一旦水泥含量，火山灰含量，水灰比，集料總額百分比意味著混凝土將用于上層建筑，就設(shè)計一批混凝土而言，配合比設(shè)計就可以開始了。具體的比重，必須準確界定每個材料被利用，以絕對體積法的比例處理。水泥是典型的被認為為具有比重的3.15?；鹕交彝ǔＴ?.22和2.77之間各有不同，火山灰供應(yīng)商應(yīng)隨時能夠為他們提供的物質(zhì)的當(dāng)前值。近似比重都確定了每個部門的批準/資格預(yù)審材料清單源，但是，他們不應(yīng)該被認為是最近的。容重，在飽和表面干燥狀態(tài)下，必須使用一定比例的粗細骨料。準確的測試一個或多個細和粗骨料樣品必須完成由承包商作為任何一個混合配料設(shè)計的一部分?？傇搭^在隨后的變化可能導(dǎo)致在容重和吸收的重大變化。以監(jiān)測為總量控制混凝土質(zhì)量的一部分，這些都是重要的屬性?；炷僚浜媳鹊姆椒ㄉ婕暗慕^對量計算的各成分含量及其對取決于1yd3或27ft3的混凝土含量。其后體積轉(zhuǎn)換為設(shè)計重量，然后成為工廠的基礎(chǔ)上生產(chǎn)的具體實際。對于膠凝材料和水，轉(zhuǎn)化為體積和重量完成的比重材料除以體重（磅）再除以水的密度。從體積重量轉(zhuǎn)換完成的，是僅僅通過已知的體積成分和乘以成份比重，并再次磅乘以水的密度之間。體積與重量都聚集轉(zhuǎn)換為計算完成的系列相同，但是，容重法（SSD）必須使用。我們的目標是建立空氣含量在6.5％的特別規(guī)定，它轉(zhuǎn)換為一個具體的量1.76ft3（三）單位重量空氣含量線性方程據(jù)了解，塑性混凝土的單位重量與空氣含量成反比的。這就是說，由于空氣含量的增加，單位重量下降。這種關(guān)系成為評估塑性混凝土?xí)r一個非常有用的工具。單位重量和空氣含量的塑料混凝土，可以很容易地和迅速地在現(xiàn)場實測其性能。一個單位重量的測量，在已知的空氣含量，即通過分偏離線性關(guān)系，提供有關(guān)信息，如耐久性、可操作性和強度，對可能出現(xiàn)的缺陷結(jié)構(gòu)和性能的潛在影響等。線性方程來預(yù)測單位重量的基礎(chǔ)上給定的空氣含量的形式如下：UW=m(空氣)+b其中：M——直線的斜率空氣是塑性混凝土含氣量b——y軸截距UM——塑性混凝土的單位重量如果所有的點的線性方程與此相關(guān)聯(lián)的解集分別繪于一圖，將有一條直線，由圖3.1所示。這種線性關(guān)系，可以決定對任何混凝土配合比設(shè)計解到，代數(shù)可以用來解決這兩個未知變量（即斜率和y軸截距）。在附錄D的形式（在選項卡11），題為“線性方程加利福尼亞的工作表”確定的格式提供，其中有兩點可以定義和公式。直角坐標（點空氣的一個解決方案，威斯康星大學(xué)）已經(jīng)可以從結(jié)構(gòu)設(shè)計。我們可以定義為2點與點的坐標（x2，y2）的。的x2=6.5％的目標空氣含量的配合比設(shè)計（即x2）的。在y2型價值是混合設(shè)計單位在規(guī)定的具體重量。這是由樓總結(jié)取得一批權(quán)重的設(shè)計絕對再除以總結(jié)了設(shè)計容量將永遠是27.00，為工作表下面的例子計算的基礎(chǔ)上配合比設(shè)計及配比值本章前面介紹的這一點。（四）水灰比的臨界值正如混凝土的單位重量是受空氣中含量的變化，也受水與膠凝材料反應(yīng)影響。由于用水量增加了，水灰比也增加了，混凝土生產(chǎn)質(zhì)量下降。這降低了在任何具體空氣含量下單位混凝土重量。由于最高允許水/用于QC/QA上層建筑混凝土膠凝比例是0.420，臨界線或限度可確定。這個臨界線將與配合比設(shè)計線性方程平行；但是，單位重量將降低。這極限值與質(zhì)量控制和進料抽樣與測試有關(guān)，以控制結(jié)果的質(zhì)量以及驗收取樣和測試。如果測量單位重量在任何特定的空氣含量等于或低于閾值，它可能表明，已超過最大水灰比。重要的是要明白，工程質(zhì)量控制中心關(guān)于為線性方程的生產(chǎn)配合比設(shè)計。有幾種方法，使更多的水可以進入混凝土混合料。本章提出的方法在此假定加的水灰比，完全是由于過量的水。這提供了一個簡單的準確測定極限值的方程。該方法首先假設(shè)的混合求解線性方程組已經(jīng)成立。通過建立一個線性方程單點以下，占混凝土與水過多，限制方程的極值確定。最簡單的一點是選擇在y軸截距，其中混凝土并沒有夾雜空氣。這一點是指第3點，有坐標（x3,y3）。該方程的臨界線與線性方程平行，斜率相同。知道了斜率和y軸截距的極限方程就可以完成。（五）配合比設(shè)計及配料工作頁如果至少有兩個點，知道是一對方程的解，代數(shù)可用來解決這兩個未知變數(shù)（即斜率和y截距）。在附錄D表（在標簽11）題為“加利福尼亞線性方程表”中提供了兩點可以定義和公式確定格式。直角坐標已經(jīng)從結(jié)構(gòu)設(shè)計提供了一種解決方案點。我們可以確定點2的坐標（x2,y2）。x2的值配合比設(shè)計的目標空氣含量（即x2=6.5%）。在y2型的值是一定配合比設(shè)計中的單位重量。這視由設(shè)計總和除以求和絕對量將永遠是27.00立方英尺而定。為工作表下面的例子計算的基礎(chǔ)上配合比設(shè)計及配比值本章前面介紹的這一點。例：x2=6.5％y2=Σ設(shè)計批次重量÷27.00ft3y2=3871lbs÷27.00ft3y2=143.4lbs/ft3（四舍五入至小數(shù)點第一位）關(guān)于點2的坐標為（x2=6.5，y2=143.4），如圖3.2所示。重要的是要注意，第2點為單位的重量計算至最接近的0.1lbs/ft3。點1，現(xiàn)在必須確定代表截距坐標（x1，y1）。這是通過從理論上消除所有缺陷和夾帶的空氣混合對混凝土的單位重量計算。這個x1的值是0.0％的空氣含量。y1的值取決于再次獲得一批設(shè)計重總和除以設(shè)計除了夾帶或夾帶空氣的絕對量，本卷將永遠27.00立方英尺-1.76立方英尺=25.24立方英尺。下面的例子說明了在工作表如何。計算一坐標點例如：x1=0