Micro silica
Microsilica concrete is a super pozzolan - a finely powdered material which can be added to cementitious matter to increase durability and to provide a positive set. It has reactive silica content of over 85%. It complies with ASTM C1240.
Advantages
- Higher compressive strength by 10-20 %
- Lower permeability resistance to penetration of water, chloride & other chemicals
- Lower free lime formation - delays ettringite and thaumasite formation
- Controls bleeding in fresh concrete
- Lower Heat of Hydration, which prevents formation of cracks.
Properties
Appearance: Very fine powder
Colour: Grey
Odour: Odourless
Silica (SiO2): 85 % minimum; mostly 90% +
Moisture: 2 % maximum
Loss on ignition at 800°C: 4 % maximum.
HOW IT WORKS
1. Pozzolonic effect : When water is added to cement, hydration occurs as shown below:
OPC + H2O → CSH (Calcium silicate hydrate) + Ca(OH)2(Free lime)
The free lime does not contribute to strength. When combined with carbon dioxide, it forms a soluble salt, which leaches through the concrete causing efflorescence, a familiar architectural problem. Concrete is also more vulnerable to chemical attack and detoriation. When it is added, the following reaction takes place:
Ca(OH)2 + SiO2 → H20 + CSH
The reaction reduces the amount of calcium hydroxide in the concrete.
2. Micro filler effect : It is an extremely fine material, with an average diameter much finer than cement. It gets well distributed in the paste, thus blocking the bleed-water channels.
PACKING
Available in 20 kg Plastic bag or Jumbo Bag.
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