Silica fume, also known as Microsilica, is an ultrafine powder subtracted from the production of silicon and ferrosilicon alloys and consists of spherical particles with a mean particle diameter of 150 nm. The main field of application is the pozzolanic material for the preparation of high-performance concrete.
- The Microsilica or Silica fume is an ultrafine material with spherical particles less than 1 µm in diameter, the average being approximately 0.15 µm. This makes it approximately 100 times smaller than the average cement particle. The apparent density of silica fume depends on the degree of densification in the silo and ranges from 130 (not densified) to 600 kg / m3.
The Microsilica it is added to 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 the addition of a very fine powder to the cement mix and from the pozzolanic reactions between the silica fume and free calcium hydroxide in the mix.
The adition of Microsilica It also reduces the permeability of concrete to chloride ions, which protects concrete reinforcing steel from corrosion, especially in chloride-rich environments such as coastal regions as well as inland roads and tracks where there is a large presence of moisture in the environment.
La Microsilica reduce significativamente el sangrado de la mezcla debido a que el agua libre se consume al mojar la gran superficie del humo de sílice y, por lo tanto, también disminuye el agua libre que queda en la mezcla por el sangrado. La Microsilica también bloquea los poros del concreto fresco para que el agua dentro del concreto no pueda salir a la superficie.
- Increases mechanical resistance.
- Increases impermeability.
- Increases chemical resistance.
- Increases adhesion to steel.
- Increases resistance to abrasion.
- Increase cohesion.
- Reduces exudation.