Micro Silica

Micro silica also known as fume, is an amorphous  (non-crystalline) polymorph of silicon dioxide, silica. It is an ultrafine powder collected as a by-product of the silicon and ferrosilicon alloy production and consists of spherical particles with an average particle diameter of 150 mm. The main field of application is as pozzolanic  for high performance concrete because of its extreme fineness and high silica  .

Applications : Silica is added to Portland cement  concrete  to improve its properties, in particular its compressive strength, bond strength, and abrasion  resistance. These improvements stem from both the mechanical improvements resulting from addition of a very fine powder to the cement paste mix as well as from the pozzolanic reactions  between the silica fume and free calcium hydroxide  in the paste.

Advantages : Addition of silica also reduces the permeability  of concrete to chloride  ions, which protects the reinforcing steel  of concrete from corrosion, especially in chloride-rich environments such as coastal regions and those of humid continental  roadways and runways (because of the use of deicing  salts) and saltwater  bridges.