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    Mix Design

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    Dhl Kshtj
    The document provides calculations to determine the material quantities and properties for a concrete mix with a target compressive strength of 30 MPa. It calculates the target mean strength as 39.79 MPa based on a characteristic strength of 30 MPa and coefficient of variation. It then determines a water-cement ratio of 0.47 and cement content of 404 kg/m3. Finally, it estimates the field quantities of cement, fine aggregate, coarse aggregate, and water required per cubic meter of concrete.

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    Mix Design

    Uploaded by

    Dhl Kshtj
    21 views6 pages
    The document provides calculations to determine the material quantities and properties for a concrete mix with a target compressive strength of 30 MPa. It calculates the target mean strength as 39.79 MPa based on a characteristic strength of 30 MPa and coefficient of variation. It then determines a water-cement ratio of 0.47 and cement content of 404 kg/m3. Finally, it estimates the field quantities of cement, fine aggregate, coarse aggregate, and water required per cubic meter of concrete.

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    MIX DESIGN`

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    The document provides calculations to determine the material quantities and properties for a concrete mix with a target compressive strength of 30 MPa. It calculates the target mean strength as 39.79 MPa based on a characteristic strength of 30 MPa and coefficient of variation. It then determines a water-cement ratio of 0.47 and cement content of 404 kg/m3. Finally, it estimates the field quantities of cement, fine aggregate, coarse aggregate, and water required per cubic meter of concrete.

    Copyright:

    © All Rights Reserved
    Download as XLSX, PDF, TXT or read online from Scribd
    Download as xlsx, pdf, or txt
    21 views6 pages

    Mix Design

    Uploaded by

    Dhl Kshtj
    The document provides calculations to determine the material quantities and properties for a concrete mix with a target compressive strength of 30 MPa. It calculates the target mean strength as 39.79 MPa based on a characteristic strength of 30 MPa and coefficient of variation. It then determines a water-cement ratio of 0.47 and cement content of 404 kg/m3. Finally, it estimates the field quantities of cement, fine aggregate, coarse aggregate, and water required per cubic meter of concrete.

    Copyright:

    © All Rights Reserved
    Download as XLSX, PDF, TXT or read online from Scribd
    Download as xlsx, pdf, or txt
    of 6

    From ACI METHOD

    Values used:

    Target compressive strength of concrete (fck)(Mpa) 30


    Density of fine aggregate(kg/m^3) 1649
    Density of coarse aggregate(kg/m^3) 1665
    Density of water (kg/m^3) 1000
    Density of cement (kg/m^3) 1440
    Specific gravity of fine aggregate 2.77
    Specific gravity of coarse aggregate 2.8
    Specific gravity of cement 3.15
    Moisture content in fine aggregate(%) 2.72
    Moisture absorption value of coarse aggregate(%) 0.5
    Fineness modulus of fine aggregate 3.6
    Slump(mm) 125
    Nominal size of coarse aggregate(mm) 40

    CALCULATION OF MEAN COMPRESSIVE STRENGTH


    For the 5% defective level specified in BS 5328, k = 1.64

    Coefficient of variation of different degrees of control is given in stanton walker's book

    We have considered the degree of control as good which corresponds to the coefficient of 15
    variation as

    ft = fck + kxS
    where
    ft=Target mean strength
    fck=Characteristic Strength
    k=constant depending upon the definition of characteristic strength and is derived from the
    mathematics of normal distribution
    S=Standard deviation of the particular mix
    We have, coefficeint of variation, Cv=S/ft

    So finally we get
    ft=(1/(1-k.Cv))*fck 39.787798
    so target mean strength 39.79

    CALCULATION OF WATER CEMENT RATIO


    W/C ratio as per ACI 211.1 and ACI 211.3. table 6.3.4

    Through interpolation for 33.16 Mpa, w/c ratio is 0.47


    SELECTION OF WATER CONTENT

    From Table 6.3.3., ACI 211.1-91

    For slump 125


    water content in lb/yd^3 for 20 mm size aggregate 332.5
    water content in kg/m^3 for 20 mm size aggregate 190
    Amount of air entrapped in % 1.5

    CALCULATION OF CEMENT CONSUMPTION

    W/C 0.47
    water content in kg/m^3 190
    cement content in kg/m^3 404

    Amount of plasticizer used in % 1.2


    so for 1 m^3 weight of plasticizer 4.848

    Aggregate is used in a ratio of 60 to 40 for coarse to fine

    V=(W+(C/Se)+(1/p)*(fa/Sfa))
    Keeping ratio of FA to CA, 40:60 0.6666667
    Calculating from the above given formulae we get,
    Coarse aggregate(kg/m^3) 1245
    Fine aggregate(kg/m^3) 616
    Estimated quantities of materials per cubic meter of concrete are
    Cement 404
    F.A. 616
    C.A. 1245
    Water 190

    These values are on SSD conditions, which is not practicle in field

    FA has moisture content (%) 2.72

    Total free surface moisture in FA(kg/m^3) 16.7552


    Weight of FA in field condition(kg/m^3) 633

    C.A. absorbs water(%) 0.5


    Quantity of water absorbed by C.A. (kg/m^3) 6.225
    Weight of CA in field condition (kg/m^3) 1239

    Extra amount of water is 10.5302


    So final field weight of water required 179

    SN

    So
    Mpa
    Mpa
    1
    1.5247524752
    3.0816831683

    Weight of
    cement(kg/m^3)

    404
    1

    1
    0.03375

    0.03375

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