Thatta Cement Company Limited produces ordinary portland cement (OPC) Grade 43 meeting the requirements of Pakistan Standard PS 232-2008(R) as follows:
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Mechanical & Physical Properties
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Thatta OPC
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Limits as per PS 232-2008(R)
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Compressive Strength (MPa)
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3 Days
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> 25
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Not less than 23
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7 Days
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> 36
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Not less than 33
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28 Days
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> 50
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Not less than 43
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Setting Time - Minutes
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Initial
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≥ 120 ≤ 140
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Not less than 30
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Final
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< 250
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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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Autoclave (%)
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< 0.30
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Not more than 0.8
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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 OPC
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Limits as per PS 232-2008(R)
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Lime saturation factor (LSF)
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> 0.90
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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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> 0.80
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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 3.0% when slag and/or limestone is added and
not more than 5.0% when fly ash and/or rice husk ash and/or silica fume is
aded as improver
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Sulphur content as sulphuric anhydride SO3
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< 2.50
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Not more than 2.5% when C3A is 5 or less. Not More
than 3.0% when C3A is greater than 5.
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Loss on ignition-percent by mass
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< 1.50
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Not more than 5
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Magnesia-percent by mass
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< 2.00
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Not more than 6
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Typical Chemical Composition of Thatta OPC 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 |
> 22.00
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> 04.00
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> 04.00
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> 62.00
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< 02.00
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< 0.40
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< 0.20
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< 02.50
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0.005
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