Specifications for Thatta Ordinary Portland Cement

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)
 3 Days
> 25
 Not less than 23
 7 Days
> 36
 Not less than 33
 28 Days
> 50
 Not less than 43
Setting Time - Minutes
 Initial
120 140
 Not less than 30
 Final
< 250
 Not less than 600
Soundness (Expansion)
 Le-Chatelier (mm)
< 1.00
 Not more than 10
 Autoclave (%)
< 0.30
 Not more than 0.8
Fineness
 Fineness-m2/kg
> 300
 Not less than 225
Chemical Requirements
Thatta OPC
Limits as per PS 232-2008(R)
 Lime saturation factor (LSF)
> 0.90
 Not greater than 1.02 and not less than  0.66
 Ratio of percentage of alumina to iron oxide
> 0.80
 Not less than 0.66
 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
 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.
 Loss on ignition-percent by mass
< 1.50 
 Not more than 5
 Magnesia-percent by mass
< 2.00
 Not more than 6
Typical Chemical Composition of Thatta OPC is given below:
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
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