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Bharathi Portland Slag cement is manufactured by inter grinding high quality clinker with carefully selected, good quality slag purchased from major steel plants and using high quality gypsum.
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Hydration of blended cement:
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Ordinary Portland Cement + water ----- C-S-H GEL+ Ca(OH)2 (Alkali)
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This alkali is a byproduct in any OPC hydration process amounting to 25% of total gel formation.
This is like a weak link in strong chain. Sulphates and chlorides present in water, soil or surrounding atmosphere attacks this alkali causing deterioration of concrete.
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Secondary gel formation in Portland Slag cement:
Slag by itself is cementitious in nature and undergoes hydration in presence of alkali resulting C-S-H gel formation
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As a result of this secondary gel formation pore refinement takes place and the concrete becomes more impermeable to sulphate and chloride attacks leading to the durability of concrete structures.
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Properties
a) Physical |
Requirements as per
IS 455-1989 |
Bharathi cement
values |
Competitors values |
| Fineness (sqm/kg) |
225 |
350 |
290 |
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Soundness (mm) |
| Lechatlier method |
10mm (max) |
1 |
1.5 |
| Autoclave (%) |
0.8 (max) |
0.03 |
0.05 |
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Setting time |
| Initial(min) |
30 minutes |
160 |
280 |
| Final(max) |
600 minutes |
250 |
340 |
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Compressive strength (MPa) |
| 3 days (min) |
16 |
33 |
25 |
| 7 days (min) |
22 |
44 |
37 |
| 28days (min) |
33 |
65 |
60 |
| b) Chemical |
| Loss on ignition (%) |
5 (max) |
0.3 |
1.08 |
| Sulphur Trioxide (SO3) |
3 (max) |
1.62 |
2.87 |
| Sulphide Sulpher (% by mass) |
1.5 (max) |
0.2 |
0.3 |
| Insoluble residue (%) |
4 (max) |
0.75 |
2.4 |
| Magnesia (%) |
6 (max) |
1 |
3.3 |
| Chloride (%) |
0.1 (max) |
0.002 |
0.02 |
| Temperature during Testing |
27±2 |
27±2 |
27±2 |
| Humidity (%) |
65±5 |
65±5 |
65±5 |
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Applications
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