Thatta Cement Company Limited produces portland blast furnace slag cement (PBFS) meeting the requirements of Pakistan Standard PS 1631-1984(R) as follows:
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Mechanical & Physical Properties
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Thatta PBFS
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Limits as per PS 1631-1984(R)
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Compressive Strength (psi)
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3 Days
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> 3000
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Not less than 2200
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7 Days
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> 4200
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Not less than 3400
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28 Days
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> 5900
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Not less than 5000
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Setting Time - Minutes
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Initial
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≥ 150 ≤175
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Not less than 30
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Final
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< 275
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Not less than 600
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Soundness (Expansion)
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Le-Chatelier (mm)
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< 1.00
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Not more than 10
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Fineness
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Fineness-m2/kg
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> 300
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Not less than 225
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Chemical Requirements
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Thatta PBFS
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Limits as per PS 1631-1984(R)
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Lime saturation factor (LSF)
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> 0.70
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Not greater than 1.02 and not less than 0.66
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Ratio of percentage of alumina to iron oxide
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< 1.00
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Not less than 0.66
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Insoluble residue percent by mass
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< 0.50
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Not more than 1.5%
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Sulphur content as sulphuric anhydride SO3
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< 2.50
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Not more than 3.0%
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Loss on ignition-percent by mass
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< 1.50
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Not more than 3.0
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Magnesia-percent by mass
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< 3.00
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Not more than 7
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Typical Chemical Composition of Thatta PBFS is given below:
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| Chemical Compound |
SiO2
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Al2O3
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Fe2O3
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CaO
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MgO
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K2O
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Na2O
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SO3
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Cl
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| Percentage by Mass |
> 24.00
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> 06.00
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> 03.00
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> 58.00
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< 03.00
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< 00.30
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< 00.20
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< 02.50
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00.01
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