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