Microsilica

Microsilica is used as highly active mineral concrete and cement agent and intended to mix high-grade concrete by strength, water resistance and high rust-proof quality.

The admissible concrete application area with microsilica (at its dosing to 20% from cement mass) - all concrete and reinforced concrete buildings of construction and industrial engineering, including potable water supply system.

Chemical composition

SiO2	Al2O3	Fe2O3	CaO	MgO	Na2O	K2O	C	S
90-92%	0,68%	0,69%	0,85%	1,01%	0,61%	1,23%	0,98%	0,26%

Physical property

Particle size	<1mkm
Density - non-compacted - compacted - suspension	from 130 to 350 kg/m³ from 480 to 720 kg/m³ from 1320 to 1440 kg/m³
Surface area	from 13 000 to 30 000 m²/kg

Advantages from use of microsilica:

• Strength gain
  Microsilica can ensure the compressive strength, much more exceeded the strength of normal concretes, and this is an aggregate strength that is the limiting factor here. At the application of natural aggregates the strength more than 150 N/mm² is reached, and at the application of special high-strength aggregates, the strength of 300 N/mm² can be reaches.
• Penetrability
  The effect of interstices filling created by pozzolanic spherical microparticle, favours to low the concrete capillary porosity and penetrability. Practically the impenetrable concrete can be received at reasonable microsilica content and rather low type I cement content. As microsilica effects more the penetrability than the strength, the concrete with microsilica will be always less permeable, than the concrete in type I cement of the same strength.
• Protection of reinforcement
  In Norway and Sweden the studies of concrete buildings at the age of 12 years showed that high-qaulity concretes with microsilica are not less stable to be carbonized than the concretes of the same strength on ordinary Portland cement and prevent much better the penetration of salt water chlorides (the great quantity of laboratory measurements of reinforcement corrosion are made. It is safe to say that on condition of proper curing the capacity of concrete with microsilica to protect steel reinforcement will not differs a lot as compared with concrete of the same strength on ordinary Portland cement).
• Freeze-thaw durability
  The low permeability and augmented cement stone density provide the good freeze-thaw durability of microsilica concrete. The microsilica is combined with the air-entraining agents. In fact the stable rheological structure of plastic microsilica concrete reduces the loss of the entrained air at transportation and vibration.
• Chemical influence
  It is known that the low permeability and low free lime content improve the concrete resistance to influence of aggressive chemicals. The microsilica concrete is possessed of all these features and shows the excellent resistance to many foreign substances. The long-term field tests in Norway showed that it was compared with sulfate resistant Portland cement by its resistance to sulfates.
• Economy
  The application of condensed microsilica in the mass construction allows to save 40% of cement not worsening the concrete characteristics and reducing the heat energy at heat and humidity processing of articles.