Thatta Cement Company Limited produces ordinary portland cement (OPC) Grade 43 meeting the requirements of Pakistan Standard PS 232-2008(R) as follows:
Mechanical & Physical Properties |
Thatta OPC |
Limits as per PS 232-2008(R) |
Compressive Strength (MPa) |
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| 3 Days |
> 25 |
Not less than 23 |
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| 7 Days |
> 36 |
Not less than 33 |
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| 28 Days |
> 50 |
Not less than 43 |
Setting Time - Minutes |
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| Initial |
≥ 120 ≤ 140 |
Not less than 30 |
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| Final |
< 250 |
Not less than 600 |
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Soundness (Expansion) |
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| Le-Chatelier (mm) |
< 1.00 |
Not more than 10 |
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| Autoclave (%) |
< 0.30 |
Not more than 0.8 |
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Fineness |
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| Fineness-m2/kg |
> 300 |
Not less than 225 |
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Chemical Requirements |
Thatta OPC |
Limits as per PS 232-2008(R) |
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Lime saturation factor (LSF)
|
> 0.90 |
Not greater than 1.02 and not less than 0.66 |
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Ratio of percentage of alumina to iron oxide |
> 0.80 |
Not less than 0.66 |
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| Insoluble residue percent by mass |
< 0.50 |
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 |
< 2.50 |
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 |
< 1.50 |
Not more than 5 |
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| Magnesia-percent by mass |
< 2.00 |
Not more than 6 |
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Typical Chemical Composition of Thatta OPC is given below: |
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| Chemical Compound | SiO2 |
Al2O3 |
Fe2O3 |
CaO |
MgO |
K2O |
Na2O |
SO3 |
Cl |
| Percentage by Mass | > 22.00 |
> 04.00 |
> 04.00 |
> 62.00 |
< 02.00 |
< 0.40 |
< 0.20 |
< 02.50 |
0.005 |