2 portland cement

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  • Cements

    1

    CVLE 321

    Structural EngineeringDepartment

    Faculty of EngineeringBeirut Arab University

    ByProf. Adel El Kordi

    &Dr. Meheddene Machaka

  • THE CEMENT MANUFACTURING PROCESS

    BLASTING : The raw materials that are used to manufacture cement (mainly limestoneand clay) are blasted from the quarry.

    TRANSPORT : The raw materials are loaded into a dumper. CRUSHING AND TRANSPORTATION : The raw materials, after crushing, are transported

    to the plant by conveyor. The plant stores the materials before they are homogenized.

    Quarry face

    . BLASTING . TRANSPORT1- quarry

    . CRUSHING & TRANSPORTATION

    crushing

    conveyor

    dumper

    storage atthe plant

    loader

    2

  • THE CEMENT MANUFACTURING PROCESS

    2- Raw grinding and burning

    . BURNING

    RAW GRINDING : The raw materials are very finely ground to produce the raw mix. BURNING : The raw mix is preheated before it goes into the kiln, which is heated by a

    flame that can be as hot as 2000 C. The raw mix burns at 1500 C producing clinkerwhich, when it leaves the kiln, is rapidly cooled with air fans. So, the raw mix is burntto produce clinker : the basic material needed to make cement.

    kiln

    cooling

    preheating

    clinker

    3

    . RAW GRINDING

  • THE CEMENT MANUFACTURING PROCESS

    .GRINDING : The clinker and the gypsum are very finely ground giving a pure cement.Other secondary additives and cementitious materials can also be added to make ablended cement..STORAGE, PACKING, DISPATCH :The cement is stored in silos before being dispatchedeither in bulk or in bags to its final destination.

    . GRINDING3- Grinding, storage, packing, dispatch

    . STORAGE, PACKING, DISPATCH

    clinkerstorage

    Gypsum and the secondary additives are addedto the clinker.

    silos

    dispatch

    bags

    Finish grinding

    4

  • Clinker Gypsum

    5

  • Fe2O3

    AL2O3

    SiO2

    CaO

    OxidesC4AFC4AF

    C3AC3A

    C2SC2S

    C3SC3S

    Compounds

    Background: Portland Cement ClinkerComponents,Oxides & Compounds.

    6

  • Preparing row materialsPreparing row materials

    Lime stoneCa CO3.2H2O

    Lime stoneCa CO3.2H2O

    Calcium OxideCa O

    Calcium OxideCa O

    Silicon OxideSiO2

    Silicon OxideSiO2

    Aluminum & Ferric OxidesFe2O3+ Al2O3+SiO3

    Aluminum & Ferric OxidesFe2O3+ Al2O3+SiO3

    Ferric oxideFe2O3

    Ferric oxideFe2O3

    Tri-calcium AluminatesC3A

    Tri-calcium AluminatesC3A

    Tetra calcium Aluminates FerriteC4AF

    Tetra calcium Aluminates FerriteC4AF

    Tri-calcium SilicateC3S

    Tri-calcium SilicateC3S

    Di-calciumSilicateC2S

    Di-calciumSilicateC2S

    Type I

    OPC

    Type I

    OPC

    Type II

    Modified PC

    Type II

    Modified PC

    Type III

    High early PC

    Type III

    High early PC

    Type IV

    Low heat PC

    Type IV

    Low heat PC

    Type V

    SRC

    Type V

    SRC

    SandSiO2SandSiO2

    siltFe2O3+ Al2O3+Sio3+SiO2

    siltFe2O3+ Al2O3+Sio3+SiO2

    Iron OreFe2O3

    Iron OreFe2O3

    Crushing & Pre-HeatingCrushing & Pre-Heating

    Weighing , kiln feeding & burningWeighing , kiln feeding & burning

    Phases of clinker for different types of Portland cementsPhases of clinker for different types of Portland cements

    Adding proper ratio of gypsum & grindingAdding proper ratio of gypsum & grinding

    Chemical Composition & Industrial Process

    7

  • Formation of Chemical Reactions.

    Fe2O3Fe2O3 AL2O3AL2O3 CaOCaO

    C4AFC4AF

    SiO2SiO2 CaOCaO

    C3SC3S

    C2SC2S CaOCaO

    AL2O3AL2O3 CaOCaO

    C3AC3A

    8

  • Effect of changes in Fe2O3on the C4AF and C3A

    Fe2O3Fe2O3

    C4AFC4AF

    C3AC3A

    9

  • Effect of changes in SiO2on the C2S and C3S

    SiO2SiO2

    C2SC2S

    C3SC3S

    10

  • Cement Compounds & Hydration

    Hydration

    process.

    Portland Cem

    ent.Portland C

    ement.

    Tr-calciumAluminates

    C3A

    Tri-calciumSilicate

    C3S

    Tetra calciumAluminates

    Ferrite

    C4AF

    Di-calciumSilicate

    C2S

    ++ ReduceDurabilityReduce

    Durability

    VoidsVoids

    CracksCracks

    Heat ofHydrationHeat of

    Hydration

    Gainingcompressive

    strengthForm the

    pastestructure

    Gel CSH

    +Fill theporespaste

    structure

    Provide alkalineprotective

    medium forsteel bars

    Ca (OH)2

    11

  • Cement Phases & rate of releasingheat of hydration.

    HydrationprocessPortland C

    ement.

    Portland Cem

    ent.

    Tr-calciumAluminate

    s

    C3A

    Tri-calciumSilicate

    C3S

    Di-calciumSilicate

    C2S

    Tetra calciumAluminates

    Ferrite

    C4AF

    800

    750710

    420380

    330

    170130

    80 13080

    40

    da y 3 da y 7 da y 2 812

  • Effect of Heat of hydration on durabilityCalories Per Gram

    FatFat

    StarchStarch

    SugarsSugars

    ProteinsProteins

    Type IIType II

    Type IType I 80 (7d.)

    63 (7d.)

    4

    4

    9

    4

    Cement heat of hydration is one of the most important factors

    affecting durability as it increases generation of cracks in concrete and

    causes concrete deterioration specially in the aggressive media.13

  • Hydration of cement phases.

    3days 7days 28days

    Hydration process.

    Portland Cem

    ent.Portland C

    ement.

    Di-calciumSilicate C2S

    CSHCSH

    +CHCH

    Tetra calciumAluminatesFerriteC4AF

    ultimatecompressivestrengthstarting from28days

    Earlycompressivestrength3days &7days

    Tri-calcium Silicate C3S

    EttringiteEttringite

    Mono( sulfate)

    phases

    Mono( sulfate)

    phases

    EttringiteEttringite

    Mono( sulfate)

    phases

    Mono( sulfate)

    phases

    Setting ofcement paste

    Setting ofcement paste

    Setting ofcement paste

    Setting ofcement paste

    Tr-calciumAluminatesC3A

    14

  • Heat of Hydration of Pure Compounds

    Heat ofHydration

    (cal/gr)

    C3S 120

    C2S 62

    C3A 207

    C4AF 100

    The amount of heatliberated is affected bythe fractions of thecompounds of thecement.

    Heat of Hydration(cal/gr)= 120*(%C3S)+62*(%C2S)+

    207*(%C3A)+100*(C4AF)

  • The requirement of ASTM C 150 varies in thethree types of cement as follows :

    1. The content Of C3A .

    2. The Content of SO3.

    For type II chemical analysis is more restrict consenting defining the content of eachof:

    Silicone oxide 20% minimum, Aluminum oxide & ferric Oxide that are 6% maximum Summation of contents of the component C3S & Component C3A is 58 %

    maximum

    Type II production needs more accuracy in Quality control

    as it is more restricted in its components

    Type I OPCType IIType V SRC

    5% 8%

    Type I OPCType IIType V SRC

    2.5% 3% 3.5 %

    C3A

    SO3

    16

  • Effects of cement chemical components & physicalproperties on concrete properties

    Cement EffectsPlace ability Cement amount, fineness, setting characteristics

    Strength Cement composition (C3S, C2S and C3A), loss on ignition,fineness

    Drying Shrinkage SO3 content, cement compositionPermeability Cement composition, finenessResistance to sulfate C3A contentResistance toChlorides C3A content

    Alkali SilicaReactivity

    Alkali content

    Cracking Cement content, Heat of hydration, C3A, C3S, air entrainedCorrosion ofembedded

    Cement Composition (esp. C3A content) steel

    C3A content is the most important component affecting properties of concrete .17

  • Cement Hydration

    18

  • Cementtype Use

    I1 General purpose cement, when there are no extenuating conditions

    II2 Aids in providing moderate resistance to sulfate attack

    III When high-early strength is required

    IV3 when low heat of hydration is required`V4 When high sulfate resistance is requiredIA4 A type I cement containing an integral air-entraining agent

    IIA4 A type II cement containing an integral air-entraining agent

    IIIA4 A type III cement containing an integral air-entraining agent

    Portland cement types and their uses:)150Types of PC (ASTM C

    1 Cements that simultaneously meet requirements of Type I and Type II are also widely available.2 Type II low alkali (total alkali as Na2O < 0.6%) is often specified in regions where aggregates susceptible to alkali-silica reactivity are employed.3 Type IV cements are only available on special request.4 These cements are in limited production and not widely available.19

  • Standard Cements (ASTM) Type I: Ordinary Portland Cement Suitable to be used in general concrete

    construction when special properties are notrequired.

    Type II: Modified Portland Cement Suitable to be used in general concrete

    construction. Main difference between TypeI&II is the moderate sulfate resistance ofType II cement due to relatively low C3Acontent (%8). Since C3A is limited rate ofreactions is slower and as a result heat ofhydration at early ages is less. *It is suitableto be used in small scale mass concrete likeretaining walls.

  • Type III: High Early Strength P.C.Strength development is rapid.3 days fc=7 days fc of Type IIt is useful for repair works, cold weather

    & for early demolding.Its early strength is due to higher C3S &

    C3A content.

    Type IV: Low Heat P.C.Generates less heat during hydration &amp

Recommended

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