Civ Cement

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    CEMENT AND CONCRETE MATERIALS

    materials fundamentals + mix design

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    CEMENT

    Materials fundamentals

    Sources of information

    Cement manufacture + composition

    Cement hydrationMicrostructure

    Concrete mixes

    Properties: strengthpermeabilitydurability

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    Information/texts

    Jackson & Dhir: Civil Engineering Materials,

    5th edn, 1997

    Mindess, Young & Darwin: Concrete, 2002

    Neville & Brooks: Concrete Technology, 1987

    Neville: Properties of Concrete 4th edn, 1995

    Bensted & Barnes: Structure and Performance

    of Cements, 2nd edn, 2001

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    Information/journals

    Cement and Concrete Research

    Magazine of Concrete Research

    American Concrete Institute JournalACI Journal

    Materials and Structures [RILEM]

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    Information/online

    Virtual Cement & Concrete Testing Laboratory:

    includes Electronic Monograph from Bentz at

    http://ciks.cbt.nist.gov/vcctl/

    See also Microstructure Images Library from Lange at

    http://sftp.cee.uiuc.edu/research/dlange/micro

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    Cement Manufacture

    Raw materials

    limestone + clay

    on firing, produces a complex mixtureof synthetic minerals, principally

    calcium silicates and calciumaluminates

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    Manufacture

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    CEMENT

    World production 2001 1.6 billion tonsSteel production 900 million tons

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    CEMENT

    World production 2001 1.6 billion tonnes

    2--5 % total CO2

    emissionEnergy intensive manufacture

    Various figures

    are quoted.

    The energy cost

    of manufacture

    is around 3500

    kJ/kg cement

    Various figures

    are quoted.

    The energy cost

    of manufactureis around 3500

    kJ/kg cement

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    CEMENT

    World production 2001 1.6 billion tonnEU production 2002 194 million tonne

    For each tonne cement produced

    0.800 tonne CO2 is also produced

    0.525 tonne from decalcinationof limestone

    0.335 tonne from combustionof fuel in the kiln

    0.050 tonne from electricity

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    CEMENT

    In EU, cement industry produces

    3 per cent of total anthropogenic CO

    Source: Cembureau

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    Civil Engineering: Materials

    Cement manufacture

    Some facts

    Cement is the industrial material produced in by far the largest tonnage: 1.6 billion tonnes worldwide 200tonnes). Most of this cement is combined with about four times that weight of aggregate to make concret

    Large-scale industrial plants: typical output of a modern cement plant is 3000 tonnes/day. Low unit cost and large production volumes mean that it is uneconomic to transport cements over long di

    countries. Therefore cement is produced in virtually every country in the world.

    Much of the worlds production capacity is owned by a small number of major industrial business congloGroup (formerly the Swiss company Holderbank) operates in 70 countries with technical centre in Zurich

    British companies include RMC and Castle (owned by the Heidelberg group). The trend towards large mensure a good technical level in cement manufacture worldwide.

    Sustainability issues

    Cement manufacture is an important source of anthropogenic CO2 emissions (see overheads).

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    Cement standards

    The long-serving British Standard for cem

    12, is being replaced by Euro-Norm EN 19

    Cement Part 1: Composition, specificati

    conformity criteria for common cements

    *Check out this document on-line via UoE

    ...needs ATHENS registration

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    Euro-Cements

    Five families

    CEM I Portland cement

    CEM II Portland-composite c

    CEM III Blastfurnace cement

    CEM IV Pozzolanic cementCEM V Composite cement

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    Euro-Cements

    Other main components of composite ce

    Blastfurnace slag

    Silica fume

    Pozzolana

    Fly ashBurnt shale

    Limestone

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    Table 22. Mineralogical Composition of Classic Cement Clinker

    Oxide Composition Cement Notatiion Common Name Concentration (wt

    3CaO SiO2

    C3S a lite 5565

    2CaO SiO2

    C2S belite 1525

    3CaO Al2O

    3C

    3A aluminate 814

    4CaO Al2O

    3 Fe

    2O

    3C

    4AF brownmillerite 812

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    Clinker microstructure

    C3S

    C2SC2AC4AF

    150 micron

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    Clinker microstructure

    C3S, C2S, C3A, C4AF200 micron

    Cement grinding

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    Cement grinding

    Gypsum additions (strictly sulphate)

    Particle size distribution

    Images from Lange

    UIUC

    http://cee.ce.uiuc.edu/lange/micro

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    Particle size

    Powder surface area

    Mean particle diameter 15-20 micron

    Direct measurement of cement particle s

    distribution is used for quality control in

    cement manufacture

    But a traditional measurement of cement

    size is the Blaine surface area

    Cement hydration 1

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    Cement hydration 1

    Heat evolution

    Induction period

    Cement hydration 2

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    Cement hydration 2

    Chemical reaction with water

    All minerals involved

    115 micron

    Cement hydration 2

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    Cement hydration 2

    Principal reaction which develops

    strength

    C3S + water ---> C-S-H

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    Cement hydration 2

    Principal reaction which develops

    strength

    C3S + water ---> C-S-H + Ca(OH)2

    Ca(OH)2

    Hydrated lime or portlandite

    Cement hydration 3

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    y

    Chemical reaction with water

    All minerals involved

    Formation of lime

    (calcium hydroxide)

    pH of pore water

    Cement hydration 4

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    y

    Water requirement

    about 30% by wt cement for complete

    reaction

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    Computational materials science

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    pCellular automaton model of cement and concrete

    D Bentz and E Garboczi NIST

    Cement hydration 6

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    Ce e t yd at o 6

    Synchrotron X-ray view

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    Summary of setting and hardening

    Workability

    Development of continuous network

    of hydrate material

    Strength development

    Porosity and permeability

    Timescale

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    Strength and strength development

    Cement Based Materials

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    Mortars

    Concrete

    Manufactured cement based materials

    Autoclaved aerated concrete

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    Transport properties

    Permeability

    Sorptivity

    see Hall & Hoff: Water Transport inBrick, Stone and Concrete 2002

    PERMEABILITY property

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    PERMEABILITY property

    Darcys law:

    u = Q/A = - kp /L

    k permeability

    Q volume rate of flow

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    A

    B