EnglishPolish

Microsilica

Description

Microsilica is a pozzolanic substance with a high SiO₂ content, consisting of fine-dispersed gray dust of spherical shape and smooth surface. The dust is captured from furnace exhaust gases during the smelting of metallurgical silicon and ferrosilicon.

Due to its extremely small particle size (average about 0.1 micron, which is 100 times smaller than the average cement grain), microsilica densely fills the space between coarse cement particles (microfilling effect). This triggers a secondary pozzolanic reaction that leads to increased strength, density, and impermeability of the cement stone.

Advantages

  • 20% increase in compressive strength and tens of times improvement in water resistance when replacing just 15% of cement – microsilica initiates a secondary pozzolanic reaction and densifies the concrete structure.
  • Threefold reduction in water absorption – particles of ~0.1 µm (100 times finer than cement) clog capillaries, making the material virtually impermeable to water and aggressive solutions.
  • 100% increase in sulfate resistance and 50% reduction in water permeability – significantly slows down reinforcement corrosion and concrete deterioration in aggressive environments.
  • High frost resistance and durability – the ultra-dense structure of the cement stone withstands multiple freeze-thaw cycles without loss of load-bearing capacity.
  • Cement savings from 400 to 250 kg/m³ – microsilica allows a reduction in binder consumption while maintaining the required strength and durability of structures.
  • Improved workability – the rheologically stable mix does not segregate and loses less air during vibration and transport.

Applications

  • Production of mortars and concretes with high performance characteristics.
  • Manufacture of insulating materials.
  • Production of ceramic and refractory products.
  • Other industrial applications requiring increased density, strength, and chemical resistance.

FAQ

Microsilica particles are 100 times finer than cement, so they fill the voids between cement grains (microfilling). Additionally, silica reacts in a secondary pozzolanic reaction with calcium hydroxide, forming additional strong compounds.

No, microsilica is a pozzolanic additive that only works in the presence of cement. Typically, 10–15% of cement is replaced to achieve optimum properties.

By using microsilica, cement consumption can be reduced from 400 kg/m³ to 250 kg/m³, while maintaining the required strength and durability of the concrete.

Yes, it improves the rheology of the mix: reduces air loss during vibration and transport, and prevents segregation and bleeding.