《材料員》課件-1 混凝土

《材料員》MaterialClerk混凝土ConcreteCONTENTS01混凝土的定義Definitionofconcrete混凝土的分類Classificationofconcrete02混凝土的特點(diǎn)Characteristicsofconcrete0301PART.01混凝土的定義Definitionofconcrete01、混凝土的定義Definitionofconcrete混凝土是現(xiàn)代土木工程中用途最廣、用量最大的建筑材料之一。從廣義來講，混凝土是由膠凝材料、粗細(xì)集料和水按適當(dāng)比例配合、拌制而成的混合物，由具有一定可塑性的漿體經(jīng)一定時(shí)間硬化而成具有一定強(qiáng)度的人造石材，統(tǒng)稱混凝土。Concreteisoneofthemostversatileandheavilyusedbuildingmaterialsinmoderncivilengineering.Inabroadsense,concreteisamixtureofcementitiousmaterials,coarseandfineaggregatesandwaterintheappropriateproportions,mixedfromacertainplasticityofthepasteafteracertainperiodoftimetohardenintoacertainstrengthofman-madestone,collectivelyknownasconcrete.01、混凝土的定義Definitionofconcrete以水泥為膠凝材料砂石為骨料的混凝土稱為水泥混凝土，在建筑工程中最為常用；以瀝青為膠凝材料砂石為骨料的混凝土稱為瀝青混凝土，在道路工程中最為常用。Concretewithcementasthecementitiousmaterialsandandgravelastheaggregateiscalledcementconcreteandismostcommonlyusedinconstructionprojects;concretewithasphaltasthecementitiousmaterialsandandgravelastheaggregateiscalledasphaltconcreteandismostcommonlyusedinroadprojects.02PART.02混凝土的分類Classificationofconcrete02、混凝土的分類Classificationofconcrete混凝土的種類很多，可根據(jù)其組成、特性與功能等從不同角度進(jìn)行分類。Therearemanytypesofconcrete,whichcanbeclassifiedfromdifferentanglesaccordingtotheircomposition,propertiesandfunctions.02、混凝土的分類Classificationofconcrete1.按表觀密度分Dividedbyapparentdensity(1)普通混凝土。表觀密度約為2400kg/m3（通常在2350～2500kg/m3之間波動(dòng)），用天然或人工砂、石為集料配制而成的混凝土，是土建工程中最常用的混凝土，主要用作各類建筑的承重結(jié)構(gòu)材料。(1)Ordinaryconcrete.Apparentdensityofabout2400kg/m3(usuallyfluctuatesbetween2350and2500kg/m3),withnaturalorartificialsandandstoneasaggregatesformulatedconcrete,isthemostcommonlyusedconcreteincivilengineering,mainlyusedasaload-bearingstructuralmaterialforvarioustypesofbuildings.普通混凝土Ordinaryconcrete(2)輕混凝土。表觀密度可以輕達(dá)1900kg/m3，往往采用陶粒等輕質(zhì)多孔的集料，或者摻入一定量的加氣劑或泡沫劑，配制成多孔結(jié)構(gòu)的輕混凝土。主要用作輕質(zhì)結(jié)構(gòu)材料和保溫絕熱材料。(2)Lightconcrete.Apparentdensitycanbeaslightas1900kg/m3,oftenusinglightweightporousaggregatessuchasceramicpellets,ormixedwithacertainamountofaeratororfoamagent,formulatedintoaporousstructureoflightconcrete.Itismainlyusedasalightweightstructuralmaterialandasathermalinsulationmaterial.(3)重混凝土。表觀密度可達(dá)3200kg/m3，是用特別密實(shí)的集料（如鋼屑、重晶石、鐵礦石等）配制而成的混凝土，因其具有防輻射功能，又稱防輻射混凝土。主要用作核能工程的屏蔽結(jié)構(gòu)材料。(3)Heavyconcrete.Theapparentdensitycanreach3200kgm3.Itisaconcretemadeofspeciallydenseaggregates(suchassteelchips,Baryte,ironore,etc.).Becauseofitsradiationprotectionfunction,itisalsocalledradiationprotectionconcrete.Mainlyusedasashieldingstructuralmaterialfornuclearenergyengineering.(2)輕混凝土。表觀密度可以輕達(dá)1900kg/m3，往往采用陶粒等輕質(zhì)多孔的集料，或者摻入一定量的加氣劑或泡沫劑，配制成多孔結(jié)構(gòu)的輕混凝土。主要用作輕質(zhì)結(jié)構(gòu)材料和保溫絕熱材料。(2)Lightconcrete.Apparentdensitycanbeaslightas1900kg/m3,oftenusinglightweightporousaggregatessuchasceramicpellets,ormixedwithacertainamountofaeratororfoamagent,formulatedintoaporousstructureoflightconcrete.Itismainlyusedasalightweightstructuralmaterialandasathermalinsulationmaterial.2.按膠凝材料分Classifiedbycementitiousmaterials可以分為水泥混凝土、石膏混凝土、水玻璃混凝土、瀝青混凝土、聚合物水泥混凝土、樹脂混凝土等。Itcanbedividedintocementconcrete,gypsumconcrete,waterglassconcrete,asphaltconcrete,polymercementconcrete,resinconcrete,etc.3.按流動(dòng)性分Dividedbyliquidity可分為干硬性混凝土、塑性混凝土、流動(dòng)性混凝土及大流動(dòng)性混凝土。Itcanbedividedintodryhardconcrete,plasticconcrete,flowconcrete,andhighflowconcrete.4.按用途分Classificationbypurpose可分為結(jié)構(gòu)混凝土、大體積混凝土、加氣混凝土、防水混凝土、耐熱混凝土、膨脹混凝土、防輻射混凝土、道路混凝土等。Itcanbedividedintostructuralconcrete,massconcrete,aeratedconcrete,waterproofconcrete,heat-resistantconcrete,expansiveconcrete,radiationresistantconcrete,roadconcrete,etc.5.按生產(chǎn)和施工方法分Classificationbyproductionandconstructionmethods可分為預(yù)拌混凝土（商品混凝土）、現(xiàn)場攪拌混凝土、泵送混凝土、噴射混凝土、碾壓混凝土、擠壓混凝土、離心混凝土、壓力灌漿混凝土等。Itcanbedividedintoready-mixedconcrete(commercialconcrete),on-sitemixedconcrete,pumpedconcrete,sprayedconcrete,rollercompactedconcrete,extrudedconcrete,centrifugalconcrete,pressuregroutingconcrete,etc.6.按抗壓強(qiáng)度分Classificationbasedoncompressivestrength抗壓強(qiáng)度小于30MPa；主要用于一些承受荷載較小的場合，如地面。Thecompressivestrengthislessthan30MPa;itismainlyusedinsomeapplicationswheretheloadislow,suchasfloors.低強(qiáng)混凝土lowstrengthconcrete6.按抗壓強(qiáng)度分Classificationbasedoncompressivestrength抗壓強(qiáng)度小于30MPa；主要用于一些承受荷載較小的場合，如地面。Thecompressivestrengthislessthan30MPa;itismainlyusedinsomeapplicationswheretheloadislow,suchasfloors.低強(qiáng)混凝土lowstrengthconcrete中強(qiáng)混凝土?？箟簭?qiáng)度為30～60MPa；是現(xiàn)今土木工程中的主要混凝土類型，應(yīng)用于各種工程中，如房屋、橋梁、路面等。Thecompressivestrengthis30-60MPa;Itisthemaintypeofconcreteincivilengineeringtodayandisusedinvariousprojects,suchashouses,bridges,roadsurfaces,etc.中強(qiáng)混凝土Mediumstrengthconcrete6.按抗壓強(qiáng)度分Classificationbasedoncompressivestrength高強(qiáng)混凝土Highstrengthconcrete抗壓強(qiáng)度大于60MPa；主要用于大荷載、抗震及對混凝土性能要求較高的場合，如高層建筑、大型橋梁等。Compressivestrengthgreaterthan60MPa;mainlyusedforlargeloads,seismicandhighrequirementsforconcreteperformance,suchashigh-risebuildings,largebridges,etc.6.按抗壓強(qiáng)度分Classificationbasedoncompressivestrength高強(qiáng)混凝土Highstrengthconcrete抗壓強(qiáng)度大于60MPa；主要用于大荷載、抗震及對混凝土性能要求較高的場合，如高層建筑、大型橋梁等。Compressivestrengthgreaterthan60MPa;mainlyusedforlargeloads,seismicandhighrequirementsforconcreteperformance,suchashigh-risebuildings,largebridges,etc.超高強(qiáng)混凝土SuperHighStrengthConcrete抗壓強(qiáng)度大于100MPa。主要用于各種重要的大型工程，如高層氣竅樁基、軍事防爆工程、大型橋梁等。Thecompressivestrengthisgreaterthan100MPa,mainlyusedinvariousimportantlarge-scaleprojects,suchashigh-risegaspilefoundations,militaryexplosion-proofprojects,largebridges,etc.混凝土的品種雖然繁多，但在實(shí)踐工程中還是以普通的水泥混凝土應(yīng)用最為廣泛，如果沒有特殊說明，狹義上我們通常稱其為混凝土，本章將做重點(diǎn)講述。Althoughtherearemanyvarietiesofconcrete,inpracticalengineeringitisthecommoncementconcretethatismostwidelyused,andifnotspecificallystated,weusuallyrefertoitinanarrowsenseasconcrete,whichwillbethefocusofthischapter.03PART.03混凝土的特點(diǎn)Characteristicsofconcrete03、混凝土的特點(diǎn)Characteristicsofconcrete普通水泥混凝土的優(yōu)點(diǎn)：Advantagesofplaincementconcrete:(1)可塑性?；炷猎谀Y(jié)前具有良好的可塑性，可澆筑成各種形狀和大小的構(gòu)件和結(jié)構(gòu)物，并可做各種飾面。(1)Plasticity.Concretehasgoodplasticitybeforesetting,andcanbepouredintovariousshapesandsizesofcomponentsandstructures,andcanbeusedforvariousfinishes.(2)安全性。硬化混凝土具有較高的力學(xué)強(qiáng)度，且與鋼筋之間具有牢固的結(jié)合力、收縮膨脹率相近，可做成鋼筋混凝土構(gòu)件或結(jié)構(gòu)物，長期承載，使結(jié)構(gòu)的安全性得到充分保證。(2)Safety.Hardenedconcretehasahighmechanicalstrength,andwithastrongbondbetweenthesteel,shrinkageandexpansionrateissimilar,canbemadeintoreinforcedconcreteelementsorstructures,long-termload-bearing,sothatthesafetyofthestructureisfullyguaranteed.普通水泥混凝土的優(yōu)點(diǎn)：Advantagesofplaincementconcrete:普通水泥混凝土的優(yōu)點(diǎn)：Advantagesofplaincementconcrete:(3)經(jīng)濟(jì)性。同其他材料相比，混凝土組成材料中的砂石等地方性材料的用量很大，且價(jià)格較低，符合就地取材和經(jīng)濟(jì)實(shí)惠的原則，結(jié)構(gòu)建成后的維護(hù)費(fèi)用也較低。(3)Economical.Comparedwithothermaterials,theamountoflocalmaterialssuchassandandgravelintheconcretecompositionislargeandlessexpensive,inlinewiththeprincipleoflocalmaterialsandeconomy,andthemaintenancecostofthestructureaftercompletionisalsolower.普通水泥混凝土的優(yōu)點(diǎn)：Advantagesofplaincementconcrete:(4)靈活性。混凝土在土木工程中適用于多種結(jié)構(gòu)形式，滿足多種施工要求。可現(xiàn)澆、可預(yù)制，也可加入各種外加劑，可以通過改變材料的組成配制不同的混凝土來滿足不同工程的需求。(4)Flexibility.Concreteissuitableforavarietyofstructuralformsincivilengineeringtomeetavarietyofconstructionrequirements.Itcanbecast-in-place,prefabricatedorwithvariousadmixtures,andcanbeformulatedtomeettheneedsofdifferentprojectsbychangingthecompositionofthematerials.普通水泥混凝土的優(yōu)點(diǎn)：Advantagesofplaincementconcrete:(5)耐火性?；炷烈话憧捎?～2h的防火時(shí)效，比鋼鐵安全得多，不會(huì)像鋼結(jié)構(gòu)建筑那樣在高溫下很快軟化而造成坍塌。(5)Fireresistance.Concretecangenerallyhave1to2hoffireresistance,muchsaferthansteel,andwillnotcollapseasquicklyassteelbuildingssoftenathightemperatures.普通水泥混凝土的優(yōu)點(diǎn)：Advantagesofplaincementconcrete:(5)耐火性?；炷烈话憧捎?～2h的防火時(shí)效，比鋼鐵安全得多，不會(huì)像鋼結(jié)構(gòu)建筑那樣在高溫下很快軟化而造成坍塌。(5)Fireresistance.Concretecangenerallyhave1to2hoffireresistance,muchsaferthansteel,andwillnotcollapseasquicklyassteelbuildingssoftenathightemperatures.(6)耐久性?；炷帘緛砭褪且环N耐久性很好的材料，古羅馬建筑經(jīng)過幾千年的風(fēng)雨依然屹立不倒，這本身就昭示著混凝土應(yīng)該"歷久彌堅(jiān)"。(6)Durability.Concreteisaverydurablematerial,andthefactthatRomanbuildingshaveremainedstandingafterthousandsofyearsofweatheringisitselfasignthatconcreteshould"lastforever".由于混凝土具有以上許多優(yōu)點(diǎn)，因此它是一種主要的土木工程材料，廣泛應(yīng)用于工業(yè)與民用建筑、道橋工程、水利工程及地下工程、隧道工程、國防建設(shè)等，它在國家基本建設(shè)中占有重要地位。Asconcretehasmanyoftheaboveadvantages,itisamajorcivilengineeringmaterial,widelyusedinindustrialandcivilbuildings,roadandbridgeworks,waterconservancyworksandundergroundworks,tunnelworks,nationaldefenceconstruction,etc.Itoccupiesanimportantpositioninthenationalcapitalconstruction.普通水泥混凝土的缺點(diǎn)：Disadvantagesofplaincementconcrete:(1)抗拉強(qiáng)度低?；炷恋目估瓘?qiáng)度是抗壓強(qiáng)度的1/10～1/15，是鋼筋抗拉強(qiáng)度的1/100左右。(1)Lowtensilestrength.Thetensilestrengthofconcreteis1/10to1/15ofthecompressivestrength,andisabout1/100ofthetensilestrengthofreinforcingsteel.普通水泥混凝土的缺點(diǎn)：Disadvantagesofplaincementconcrete:(2)延展性不高。混凝土是一種脆性材料，抵抗變形能力較差，只能承受少量的張力變形，易開裂發(fā)生脆性破壞；抗沖擊能力差，在沖擊或震動(dòng)荷載作用下容易產(chǎn)生脆斷。(2)Ductilityisnothigh.Concreteisabrittlematerial,poorresistancetodeformation,canonlywithstandasmallamountoftensiondeformation,easytocrackbrittledamage;poorimpactresistance,easytoproducebrittlefractureundertheimpactorvibrationload.普通水泥混凝土的缺點(diǎn)：Disadvantagesofplaincementconcrete:(3)自重大，體積大，比強(qiáng)度低。給施工和使用均帶來較大的不便，尤其對高層、大跨度建筑物要求材料在保證力學(xué)性質(zhì)的前提下，以輕為宜。(3)Self-important,largevolume,lowspecificstrength.Totheconstructionanduseofbothbringgreaterinconvenience,especiallyforhigh-rise,large-spanbuildingsrequirematerialstoensurethemechanicalpropertiesofthepremise,inordertolightappropriate.普通水泥混凝土的缺點(diǎn)：Disadvantagesofplaincementconcrete:(4)體積不穩(wěn)定性。尤其是當(dāng)水泥漿量過大時(shí)，干縮開裂易變形更加突出，隨著溫度、濕度、環(huán)境介質(zhì)的變化，更易引發(fā)體積變化，產(chǎn)生裂紋等內(nèi)部缺陷，直接影響建筑物的使用壽命。(4)Volumeinstability.Especiallywhentheamountofcementpasteistoolarge,dryshrinkagecrackingeasydeformationmoreprominent,withthetemperature,humidity,environmentalmediachanges,morelikelytotriggervolumechanges,resultingincracksandotherinternaldefects,directlyaffectingtheservicelifeofthebuilding.普通水泥混凝土的缺點(diǎn)：Disadvantagesofplaincementconcrete:(5)養(yǎng)護(hù)周期較長，從而延長了施工時(shí)間。(5)Longermaintenancecyclesandthuslongerconstructiontimes.普通水泥混凝土的缺點(diǎn)：Disadvantagesofplaincementconcrete:(5)養(yǎng)護(hù)周期較長，從而延長了施工時(shí)間。(5)Longermaintenancecyclesandthuslongerconstructiontimes.(6)生產(chǎn)工藝復(fù)雜，從配料、拌和、澆筑、振搗、養(yǎng)護(hù)等眾多工序，易產(chǎn)生質(zhì)量波動(dòng)，容易產(chǎn)生裂紋、缺棱、掉角、麻面、蜂窩、露筋等常見的質(zhì)量通病，而延長了施工時(shí)間。(6)Theproductionprocessiscomplicated,fromingredients,mixing,pouring,pounding,maintenanceandmanyotherprocesses,easytoproducequalityfluctuations,easytoproducecracks,missingedges,fallingcorners,pockmarked,honeycomb,exposedtendonsandothercommonqualitycommonproblems.Theconstructiontimeisextended.《材料員》MaterialClerk普通水泥混凝土的組成材料ComponentmaterialsofordinarycementconcreteCONTENTS拌合及養(yǎng)護(hù)用水Mixingandmaintenancewater02細(xì)集料（砂子）Fineaggregates(sand)03粗集料（石子）Coarseaggregates(stones)0401水泥Cement普通水泥混凝土（簡稱混凝土）是由水泥、水、砂、石組成。砂、石集料主要起骨架作用；水泥與水形成的水泥漿包裹在集料表面并填充其空隙，在混凝土硬化前起潤滑作用，賦予混凝土拌合物一定的流動(dòng)性，以便于施工；在混凝土硬化后起膠結(jié)作用，使混凝土具有一定的強(qiáng)度?；炷恋募夹g(shù)性質(zhì)很大程度上是由原材料的性質(zhì)及其含量決定的，要得到優(yōu)質(zhì)的混凝土，應(yīng)正確選用原材料。Ordinarycementconcrete(concreteforshort)iscomposedofcement,water,sandandstone.Sandandstoneaggregatesmainlyplayaskeletalrole;cementandwaterformacementpastewrappedaroundthesurfaceoftheaggregatesandfilltheirvoids,playingalubricatingrolebeforetheconcretehardens,givingtheconcretemixacertaindegreeoffluiditytofacilitateconstruction;aftertheconcretehardens,itplaysacementingrole,givingtheconcreteacertaindegreeofstrength.Thetechnicalpropertiesofconcretearelargelydeterminedbythenatureoftherawmaterialsandtheircontent,togetqualityconcrete,thecorrectchoiceofrawmaterials.01PART.01水泥Cement水泥是混凝土的膠結(jié)材料，混凝土的性能很大程度上取決于水泥的質(zhì)量，在選擇水泥時(shí)應(yīng)對水泥的品種和強(qiáng)度等級(jí)加以正確的選擇。Cementisthecementitiousmaterialforconcreteandtheperformanceofconcretedependslargelyonthequalityofthecement,sothecorrectchoiceofcementspeciesandstrengthgradeshouldbemadewhenselectingcement.水泥Cement1.水泥品種的選擇Selectionofcementvarieties配制混凝土用水泥通常依據(jù)工程特點(diǎn)、混凝土所處的環(huán)境與氣候條件、工程部位以及水泥的供應(yīng)情況等綜合考慮。Thecementusedtoprepareconcreteisusuallybasedonthecharacteristicsoftheproject,theenvironmentalandclimaticconditionsinwhichtheconcreteislocated,thepartoftheprojectandtheavailabilityofcement.2.強(qiáng)度等級(jí)的選擇Choiceofstrengthclass應(yīng)根據(jù)混凝土的強(qiáng)度等級(jí)要求來確定，使水泥的強(qiáng)度等級(jí)與混凝土的強(qiáng)度等級(jí)相適應(yīng)；高強(qiáng)度等級(jí)的混凝土應(yīng)選用高強(qiáng)度等級(jí)的水泥；低強(qiáng)度等級(jí)的混凝土應(yīng)選用低強(qiáng)度等級(jí)的水泥。經(jīng)驗(yàn)表明，一般水泥的強(qiáng)度等級(jí)應(yīng)為混凝土強(qiáng)度等級(jí)的1.5～2.0倍。如配制C25混凝土，可選用強(qiáng)度等級(jí)為42.5的水泥；如配制C30的混凝土，可選用強(qiáng)度等級(jí)為52.5的水泥。Thestrengthleveloftheconcreteshouldbedeterminedaccordingtotherequirementsofthestrengthleveloftheconcrete,sothatthestrengthlevelofthecementiscompatiblewiththestrengthleveloftheconcrete;highstrengthleveloftheconcreteshouldbeselectedwithhighstrengthlevelofthecement;lowstrengthleveloftheconcreteshouldbeselectedwithlowstrengthlevelofthecement.Experienceshowsthatthestrengthgradeofcementshouldgenerallybe1.5to2.0timesthestrengthgradeoftheconcrete.Forexample,forC25concrete,thestrengthgradeof42.5cementcanbeused;forC30concrete,thestrengthgradeof52.5cementcanbeused.02PART.02拌合及養(yǎng)護(hù)用水Mixingandmaintenancewater水water水是混凝土的主要組成材料之一，拌和和養(yǎng)護(hù)用水不符合要求，可能產(chǎn)生多種有害作用，最常見的有：Waterisoneofthemainconstituentmaterialsofconcreteandfailuretomeettherequirementsformixingandcuringwatercanhaveavarietyofharmfuleffects,themostcommonofwhichare:1.影響混凝土的工作性和凝結(jié)硬化；affectstheworkabilityandsettingandhardeningofconcrete;2.有損于混凝土強(qiáng)度的發(fā)展；detrimentaltothedevelopmentofthestrengthoftheconcrete;3.降低混凝土的耐久性、加快鋼筋的腐蝕和導(dǎo)致預(yù)應(yīng)力鋼筋的脆斷；Reducingthedurabilityofconcrete,acceleratingcorrosionofreinforcementandcausingbrittlefractureofprestressedreinforcement;1.影響混凝土的工作性和凝結(jié)硬化；affectstheworkabilityandsettingandhardeningofconcrete;2.有損于混凝土強(qiáng)度的發(fā)展；detrimentaltothedevelopmentofthestrengthoftheconcrete;3.降低混凝土的耐久性、加快鋼筋的腐蝕和導(dǎo)致預(yù)應(yīng)力鋼筋的脆斷；Reducingthedurabilityofconcrete,acceleratingcorrosionofreinforcementandcausingbrittlefractureofprestressedreinforcement;1.影響混凝土的工作性和凝結(jié)硬化；affectstheworkabilityandsettingandhardeningofconcrete;2.有損于混凝土強(qiáng)度的發(fā)展；detrimentaltothedevelopmentofthestrengthoftheconcrete;3.降低混凝土的耐久性、加快鋼筋的腐蝕和導(dǎo)致預(yù)應(yīng)力鋼筋的脆斷；Reducingthedurabilityofconcrete,acceleratingcorrosionofreinforcementandcausingbrittlefractureofprestressedreinforcement;3.降低混凝土的耐久性、加快鋼筋的腐蝕和導(dǎo)致預(yù)應(yīng)力鋼筋的脆斷；Reducingthedurabilityofconcrete,acceleratingcorrosionofreinforcementandcausingbrittlefractureofprestressedreinforcement;4.使混凝土表面出現(xiàn)污斑等。因此，為保證混凝土的質(zhì)量和耐久性，必須使用合格的水拌制混凝土。4.Maketheconcretesurfaceappearstains,etc.Therefore,inordertoensurethequalityanddurabilityofconcrete,itisnecessarytousequalifiedwatertomixconcrete.凡可飲用之水，皆可用于拌制和養(yǎng)護(hù)混凝土。而未經(jīng)處理的工業(yè)及生活廢水、污水、沼澤水以及pH值小于4的酸性水等均不能使用。Allpotablewatercanbeusedformixingandcuringconcrete.Untreatedindustrialanddomesticwastewater,sewage,swampwaterandacidicwaterwithapHlessthan4cannotbeused.03PART.03細(xì)集料（砂子）Fineaggregates(sand)砂石集料Sandandgravelaggregates1.細(xì)集料（砂子）：天然砂、人工砂Fineaggregates(sand):naturalsand,artificialsand混凝土中粒徑范圍一般為0.15～4.75mm之間的集料為細(xì)集料。Aggregatesinconcretewithaparticlesizerangeof0.15to4.75mmaregenerallyfineaggregates.天然砂指的是由天然的巖石經(jīng)風(fēng)化后形成的大小不等、由不同礦物散粒組成的混合物。Naturalsandreferstoamixtureofdifferentmineralscattersofvaryingsizesformedbyweatheringofnaturalrock.河砂Riversand湖砂Lakesand海砂Seasand山砂Mountainsand人工砂則是將巖石粉碎磨細(xì)而成的，雖然富有棱角，表面也比較潔凈，但其中常含有一定量的片狀顆粒和石粉。Artificialsandismadefromcrushedandfinelygroundrock,andalthoughitisangularandhasarelativelycleansurface,itoftencontainsacertainamountofflakyparticlesandstonedust.拌制混凝土要選用質(zhì)量優(yōu)良的細(xì)集料，對細(xì)集料的質(zhì)量要求主要有以下幾個(gè)方面：Mixingconcretetousegoodqualityfineaggregate,thequalityoffineaggregaterequirementsaremainlythefollowing:（1）有害雜質(zhì)含量Contentofharmfulimpurities（2）堅(jiān)固性Firmness（3）粗細(xì)程度與顆粒級(jí)配Coarsenessandparticlegradation（4）含水狀態(tài)Watercontent（1）有害雜質(zhì)含量。細(xì)集料中凡含有會(huì)降低混凝土強(qiáng)度和耐久性等物質(zhì)統(tǒng)稱為有害雜質(zhì)。如云母、輕物質(zhì)、淤泥、硫化物及硫酸鹽、氯鹽、有機(jī)物等。(1)Harmfulimpuritycontent.Fineaggregatescontainingsubstancesthatwillreducethestrengthanddurabilityofconcretearecollectivelyreferredtoasharmfulimpurities.Suchasmica,lightmaterial,silt,sulphideandsulphate,chloridesalts,organicmatter,etc.（1）有害雜質(zhì)含量。細(xì)集料中凡含有會(huì)降低混凝土強(qiáng)度和耐久性等物質(zhì)統(tǒng)稱為有害雜質(zhì)。如云母、輕物質(zhì)、淤泥、硫化物及硫酸鹽、氯鹽、有機(jī)物等。(1)Harmfulimpuritycontent.Fineaggregatescontainingsubstancesthatwillreducethestrengthanddurabilityofconcretearecollectivelyreferredtoasharmfulimpurities.Suchasmica,lightmaterial,silt,sulphideandsulphate,chloridesalts,organicmatter,etc.硫化物及硫酸鹽雜質(zhì)對水泥有侵蝕作用，降低混凝土的耐久性；有機(jī)質(zhì)影響水泥的水化硬化；氯鹽雜質(zhì)易引起鋼筋銹蝕。因此，對預(yù)應(yīng)力鋼筋混凝土結(jié)構(gòu)不宜采用海砂。Sulphideandsulphateimpuritieshaveanerosiveeffectoncement,reducingthedurabilityofconcrete;organicmatteraffectsthehydrationandhardeningofcement;chloridesaltimpuritiesarelikelytocauserustingofreinforcingsteel.Therefore,itisnotadvisabletouseseasandforprestressedreinforcedconcretestructures.（2）堅(jiān)固性。細(xì)集料的堅(jiān)固性是指砂在氣候、外力或其他物理因素作用下抵抗破碎的能力。(2)Firmness.Firmnessoffineaggregatesreferstotheabilityofsandtoresistcrushingundertheactionofweather,externalforcesorotherphysicalfactors.天然砂通常用飽和硫酸鈉溶液浸泡法來檢驗(yàn)顆粒抵抗膨脹應(yīng)力的能力。此法是先將集料試樣浸泡于硫酸鈉飽和溶液中，使溶液滲入集料的孔隙中，然后取出試樣烘烤，使孔隙中的溶液結(jié)晶膨脹產(chǎn)生內(nèi)應(yīng)力，如此循環(huán)進(jìn)行5次，其最終的質(zhì)量損失百分率來評(píng)定砂的堅(jiān)固性。Naturalsandsareusuallytestedfortheirabilitytoresistswellingstressbysoakingtheminasaturatedsodiumsulphatesolution.Thismethodinvolvesimmersinganaggregatespecimeninasaturatedsodiumsulphatesolution,allowingthesolutiontopenetrateintotheporesoftheaggregate,thenremovingthespecimenandbakingitsothatthesolutionintheporescrystallisesandexpandstoproduceinternalstress,andsoonforfivecycles,withthefinalpercentagelossinmasstoassesstherobustnessofthesand.人工砂通?？刹捎脡核橹笜?biāo)法進(jìn)行實(shí)驗(yàn)。壓碎指標(biāo)試驗(yàn)是將一定重量（通常330克）在烘干狀態(tài)下單粒級(jí)的砂子裝入受壓鋼模內(nèi)，以500N/s的速度加荷，至25KN時(shí)穩(wěn)荷5s后，以同樣速度卸荷。然后進(jìn)行篩分，稱出試樣的篩余量和通過量，壓碎指標(biāo)可用其質(zhì)量損失百分率來表示。Artificialsandcanusuallybetestedusingthecrushingindexmethod.Thecrushingindextestinvolvesloadingacertainweight(usually330g)ofsinglegrainsandinadrystateintoapressurisedsteelmould,applyingaloadatarateof500N/s,holdingitsteadyfor5sat25KNandthenunloadingitatthesamerate.Sievingisthencarriedoutandthespecimenisweighedforsievemarginandthroughput,andthecrushingindexcanbeexpressedintermsofitspercentagemassloss.（3）粗細(xì)程度與顆粒級(jí)配(3)Coarsenessandparticlegradation砂子的粗細(xì)程度是指不同粒徑的砂混合在一起的總體粗細(xì)程度，一般分為粗砂、中砂、細(xì)砂和特細(xì)砂。在砂用量一定的情況下，如砂過粗，混凝土拌合物的粘聚性較差，容易發(fā)生分層離析現(xiàn)象；如砂過細(xì)，總表面積大，消耗的水泥漿量多，不經(jīng)濟(jì)。所以，混凝土用砂的粗細(xì)程度應(yīng)適當(dāng)。Thecoarsenessofthesandreferstotheoverallcoarsenessofthesandmixedtogetherwithdifferentgrainsizes,generallydividedintocoarsesand,mediumsand,finesandandextrafinesand.Inthecaseofacertainamountofsand,suchassandistoocoarse,thecohesionoftheconcretemixispoor,pronetodelaminationandsegregation;suchassandistoofine,thetotalsurfaceareaislarge,theamountofcementpasteconsumed,noteconomic.Therefore,thedegreeofcoarsenessofsandforconcreteshouldbeappropriate.砂子的顆粒級(jí)配是指粒徑大小不同的砂子顆粒相互組合搭配的比例情況。級(jí)配良好的砂應(yīng)該是不同粒徑的砂子互相填充，使砂子的空隙率達(dá)到盡可能的小。用級(jí)配良好的砂子配制混凝土，不僅可以減少水泥漿用量，而且因水泥石含量小而使得混凝土的密度得到提高，強(qiáng)度和耐久性也得以加強(qiáng)。Thegraingradationofsandreferstotheproportionofsandparticlesofdifferentgrainsizesthatarecombinedandmatchedwitheachother.Well-gradedsandshouldbefilledwithsandofdifferentgrainsizessothatthevoidratioofthesandisassmallaspossible.Concretewithwell-gradedsandcannotonlyreducetheamountofcementpaste,butalsothedensityofconcreteisimprovedduetothesmallcementstonecontent,andthestrengthanddurabilityisenhanced.綜上所述，混凝土用砂同時(shí)考慮砂的粗細(xì)程度和顆粒級(jí)配。細(xì)度模數(shù)相同而級(jí)配不同的砂所配制的混凝土的性質(zhì)是不同的。當(dāng)砂的顆粒較粗且級(jí)配較好時(shí)，砂的空隙率和總表面積就較小，這樣不僅可以節(jié)約水泥，還可提高混凝土的強(qiáng)度和密實(shí)度。砂的粗細(xì)程度和顆粒級(jí)配可用篩分析的方法進(jìn)行評(píng)定。Insummary,sandforconcretetakesintoaccountboththecoarsenessofthesandandthegradationoftheparticles.Thepropertiesofconcretepreparedfromsandwiththesamefinenessmodulusbutdifferentgradingaredifferent.Whenthesandiscoarserandbettergraded,thevoidratioandtotalsurfaceareaofthesandissmaller,whichnotonlysavescement,butalsoimprovesthestrengthandcompactnessoftheconcrete.Thecoarsenessandgradationofthesandcanbeassessedbymeansofsieveanalysis.04PART.04粗集料（石子）Coarseaggregates(stones)2.粗集料（石子）：碎石、卵石2.Coarseaggregates(stones):crushedstone,pebbles混凝土中粒徑大于4.75mm的巖石顆粒為粗集料。Rockparticleswithaparticlesizegreaterthan4.75mminconcretearecoarseaggregates.卵石（礫石）是由天然巖石經(jīng)自然風(fēng)化、水流沖刷搬運(yùn)、堆積形成的，按其產(chǎn)源的不同可分為河卵石、海卵石、及山卵石等幾種，其中河卵石應(yīng)用較多。Pebbles(gravel)areformedbynaturalrockthroughnaturalweathering,watererosion,andaccumulation,andcanbedividedintoriverpebbles,seapebbles,andmountainpebblesaccordingtotheirsources.卵石（礫石）是由天然巖石經(jīng)自然風(fēng)化、水流沖刷搬運(yùn)、堆積形成的，按其產(chǎn)源的不同可分為河卵石、海卵石、及山卵石等幾種，其中河卵石應(yīng)用較多。Pebbles(gravel)areformedbynaturalrockthroughnaturalweathering,watererosion,andaccumulation,andcanbedividedintoriverpebbles,seapebbles,andmountainpebblesaccordingtotheirsources.河卵石Riverpebbles海卵石Seapebbles山卵石Mountainpebbles卵石中有機(jī)雜質(zhì)含量較多，但其表面光滑、棱角少、空隙率及表面積小、拌制的混凝土水泥漿用量少、和易性較好，但與水泥石的膠結(jié)力較差。Moreorganicimpuritiesinthepebbles,butitssurfaceissmooth,lessangular,smallvoidratioandsurfacearea,lessconcretecementslurrymix,bettercompatibility,butpoorcementationwithcementstone.碎石表面粗糙，棱角多、空隙率及表面積較大、較潔凈，拌制的混凝土水泥漿用量較多，和易性較差，但與水泥石的膠結(jié)能力較強(qiáng)。Thesurfaceofthecrushedstoneisrough,withmoreangles,largervoidratioandsurfacearea,cleaner,moreconcretecementpasteismixed,andthecompatibilityispoor,butthecementingabilitywiththecementstoneisstronger.在相同的條件下，碎石混凝土較卵石混凝土的強(qiáng)度很高。Underthesameconditions,crushedconcretehasaveryhighstrengthcomparedtopebbleconcrete.拌制混凝土要選用質(zhì)量優(yōu)良的粗集料，對粗集料的質(zhì)量要求主要有以下幾個(gè)方面：Theconcreteshouldbemixedwithgoodqualitycoarseaggregates,thequalityrequirementsforcoarseaggregatesaremainlyasfollows:（1）強(qiáng)度Strength（2）堅(jiān)固性Firmness（3）顆粒形狀及表面特征Particleshapeandsurfacecharacteristics（4）最大粒徑與顆粒級(jí)配Maximumparticlesizeandparticlegradation（5）有害雜質(zhì)含量Contentofharmfulimpurities（6）含水狀態(tài)Watercontent（1）強(qiáng)度Strength為了保證混凝土的強(qiáng)度，要求粗集料質(zhì)地致密，具有足夠的強(qiáng)度。粗集料的強(qiáng)度可用巖石立方體抗壓強(qiáng)度或壓碎指標(biāo)來表示。測定巖石立方體抗壓強(qiáng)度時(shí)，應(yīng)用母巖制成50mm的立方體試件，在浸水飽和狀態(tài)下（48h）測其極限抗壓強(qiáng)度值。壓碎指標(biāo)是測定粗集料抵抗壓碎能力的強(qiáng)弱指標(biāo)。用壓碎、篩分后的質(zhì)量損失百分率表示。壓碎指標(biāo)愈小，粗集料抵抗受壓破壞能力愈強(qiáng)。Inordertoensurethestrengthoftheconcrete,thecoarseaggregateisrequiredtobedenseandofsufficientstrength.Thestrengthofcoarseaggregatecanbeexpressedintermsofthecubiccompressivestrengthofrockorcrushingindex.Todeterminethecompressivestrengthofarockcube,a50mmcubespecimenoftheparentrockshouldbemadeanditsultimatecompressivestrengthmeasuredinasaturatedstateofwater(48h).Thecrushingindexisanindicatorofthestrengthofthecoarseaggregate'sabilitytoresistcrushing.Itisexpressedasapercentagelossofmassaftercrushingandsieving.Thesmallerthecrushingindex,thestrongertheresistanceofthecoarseaggregatetodamagebycompression.（2）堅(jiān)固性Firmness混凝土中，粗集料起骨架作用，必須具有足夠的堅(jiān)固性和強(qiáng)度。粗集料的堅(jiān)固性是指卵石或碎石在氣候、環(huán)境變化或其他物理化學(xué)因素作用下抵抗破壞的能力。為保證混凝土的耐久性，混凝土用粗集料應(yīng)具有很強(qiáng)的堅(jiān)固性，以抵抗凍融和自然因素的風(fēng)化作用。粗集料的堅(jiān)固性測定是用飽和硫酸鈉溶液浸泡粗集料試樣經(jīng)5次循環(huán)后的質(zhì)量損失來檢驗(yàn)的。Inconcrete,thecoarseaggregateactsasaskeletonandmustbeofsufficientfirmnessandstrength.Therobustnessofcoarseaggregatereferstotheabilityofthepebblesoraggregatestoresistdamageundertheeffectsofclimate,environmentalchangesorotherphysicalandchemicalfactors.Toensurethedurabilityofconcrete,coarseaggregatesforconcreteshouldbestrongenoughtoresisttheeffectsoffreeze-thawandweatheringbynaturalelements.Therobustnessofcoarseaggregatesisdeterminedbytestingthelossofmassofcoarseaggregatespecimensafterfivecyclesofimmersioninsaturatedsodiumsulphatesolution.（3）顆粒形狀及表面特征Particleshapeandsurfacecharacteristics為提高混凝土強(qiáng)度和減小集料間的空隙，粗集料較理想的顆粒形狀是三維長度相近或相等的立方體或球形顆粒。粗集料中常含有針狀和片狀的顆粒，它會(huì)使粗集料的空隙率增大，且受力后易被折斷。故針、片狀顆粒含量過多，會(huì)降低混凝土強(qiáng)度。Inordertoimprovethestrengthofconcreteandreducethevoidsbetweentheaggregates,theidealparticleshapeofcoarseaggregateisathree-dimensionallengthofsimilarorequalcubicorsphericalparticles.Coarseaggregateoftencontainsneedle-likeandflakyparticles,itwillmakethevoidrateofcoarseaggregateincreased,andeasytobebrokenaftertheforce.Therefore,theexcessivecontentofneedleandflakeparticleswillreducethestrengthofconcrete.（4）最大粒徑與顆粒級(jí)配Maximumparticlesizeandparticlegradation粗集料公稱粒級(jí)的上限稱為該粒級(jí)的最大粒徑，如采用4.75～37.5mm的粗集料時(shí)，其最大粒徑為37.5mm。最大粒徑的大小表示粗集料的粗細(xì)程度，最大粒徑增大時(shí)，單位體積集料的總表面積減小，因而可使水泥漿用量減少，這不僅能夠節(jié)約水，而且有助于提高混凝土的密實(shí)度，減少發(fā)熱量及混凝土的體積收縮。試驗(yàn)研究證明，在普通配合比的結(jié)構(gòu)混凝土中，粗集料粒徑大于37.5mm后，由于減少用水量獲得的強(qiáng)度提高被較少的粘結(jié)面積及大粒徑骨料造成的不均勻性的不利影響所抵消，因此粗集料粒徑不宜過大。Themaximumparticlesizeofcoarseaggregateiscalledthemaximumparticlesize,suchastheuseof4.75~37.5mmcoarseaggregate,themaximumparticlesizeis37.5mm.thesizeofthemaximumparticlesizeindicatesthecoarsenessofcoarseaggregate,themaximumparticlesizeincreases,thetotalsurfaceareaperunitvolumeofaggregateisreduced,thusreducingtheamountofcementpaste,whichnotonlysaveswater,butalsohelpstoimprovethecompactnessofconcrete,reduceheatandvolumeshrinkageofcon