Undensified Silica Fume

Home / Undensified Silica Fume

Undensified Silica Fume (Microsilica)

Undensified Silica Fume, also known as raw silica fume or primary silica fume, it is chemically similar to densified silica fume, but a different density.This type of silica fume is incredibly light, has a density of 250-350 kg/m3, is very active, and requires a large storage space.

Undensified silica fume is more convenient to use, because of the characteristics of small particles, easy to disperse, basically do not need to increase the concrete mixing time. It has the characteristics of increasing the compressive and flexural strength of concrete, water penetration resistance, good filling effect and good adaptability to water reducing agents. The color of as-built silica fume will be lighter than that of densified silica fume, so it will not deepen the color of concrete.

The low bulk density of Undensified silica fume leads to higher transport costs,manufacturers need to invest more packaging costs, in addition, the Undensified silica fume is more active, easy to drift caused by the phenomenon of fly ash on site feeding, resulting in secondary pollution.

SiO2 Content: >85%
Grade: 85U
SiO2 Content: >92%
Grade: 92U
SiO2 Content: >94%
Grade: 94U
SiO2 Content: >96%
Grade: 96U
SiO2 Content: >99%
Grade: 99U

Undensified Silica Fume Advantages

Greater Impermeability

Barring the ingress of moisture, chemicals and other contaminants

High Early Strengths

Assuring increased efficiency and greater cost effectiveness in production of prestressed and precast concrete

High Compressive Strengths

Proportionate to amount of silica fume and the water-to-cementitious ratio

Greater Resistance

Substantially greater resistance to corrosion, abrasion and erosion, chemical attack and freeze/thaw damage

Undensified Silica Fume Applications

  • Refractories. Silica fume is commonly used in castable, sintered, and fused refractories. For example, it can be used in high-performance, high-grade, and low-cement refractory castables and prefabricated parts, air permeable bricks, large-scale iron trenches and ladles, and more.
  • Mortar and concrete. Silica fume can also be used for harbour wharfs, high-rise buildings, railway bridges, reservoir dams, concrete pavement, and more.
  • Protective coatings. Nano-silica sol serves as an active material for fire protection, environmental protection, and anticorrosive coating.
  • Wall and decorative materials. Silica fume can also be used for thermal insulation mortar, polymer mortar, and as an interface agent for wall insulation.
  • Putty. Microsilica can be used in putty powder for exterior and interior wall insulation.
  • Filling and reinforcement. It is also used as filling and reinforcing materials in resin, rubber, paint, unsaturated polyester, and more.
  • Additives. Finally, silica fume is commonly used as an additive in other active areas.


The only silica fume factory in China that uses machine packaging.
We can also produce according to your requirement.
The machine is automatically packed and filtered by a screen, so that no debris is mixed in.

Request a Quote

All information provided will be kept confidential.