MICRO-SILICA is finely powdered material, added to concrete for higher strength & lower permeability. 25kg or Jumbo bag.
CETEX MICRO-SILICA 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 complies with ASTM C1240.
ü Higher compressive strength by 10-20 %
ü Lower permeability – resistance to penetration of water, chloride & other chemicals
ü Lower free lime formation - delays ettringite and thaumasite formation
ü Controls bleeding in fresh concrete
ü Lower Heat of Hydration, which prevents formation of cracks.
Appearance Very fine powder
Mean particle size 25 microns
SiO2 – Silica 85 % minimum
Humidity 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.
Available in 25 kg Plastic bag or Jumbo Bag.