Silica fume was discovered as a by-product of the silicon metal production process. However, it has proved high-value thanks to its physical and chemical properties. It is also a reactive pozzolan (material of volcanic origin). It is added to concrete to get high strength and durability. Due to its small particle size, silica fume can fill the voids within the cement particles. Adding silica fume to mortar, cement concrete, and even refractory castables can help with several applications.

Micro silica fume applications

• Small particle sizes of micro silica fume bring a filling effect in cement for improved durability and strength
• Rheological properties of cement can be improved by adding micro silica fume
• Improved flexural strength
• Strontium aggregate reaction can be prevented
• High resistance to pressure
• Low cement and concrete castables exhibit higher durability and reduced costs when silica fume is added to their preparation
• Improved permeability

Benefits of adding micro silica fume

• Greater corrosion resistance
• Enhanced durability and wear resistance
• The addition of silica increases water retention, thereby reducing bleeding at the time of concrete application
• Exposure to highly reactive chemicals does not affect the longevity of silica fume-added materials. Sulfates and chloride environments do not reduce the life of the material.
• Silica fume shotcrete can achieve a thicker layer with a single spray

Physical properties of micro silica fume

• The small particle size of spherical molecules in the range of 100 to 200nm
• Silica fume has a high density of about 500 to 700 kilograms per cubic meter which make it an ideal addition to increase the overall density of cement mix
• Micro silica fume contains about 85 to 97% of SiO2 (silicon dioxide)
• Other constituents of micro silica fume include carbon and sulfur with small amounts of oxides of iron, aluminum, magnesium, sodium, calcium, and potassium

Significant advantages of adding micro silica fume to cement

The addition of micro silica fume to ordinary cement can help achieve the following traits:

• Improved bonding among cement molecules
• Cohesion among cement molecules is greatly improved
• Greater compressive strength as fine-sized silica fume molecules fill the voids in cement mix and avoid cracking
• Due to the filling effect of silica fume, the cement mix is left with minimal void space that leads to a reduction in permeability
• Cement with added silica fume will have less heat of hydration
• The overall durability of cement mix is improved
• Silica fume adds higher resistance to alkali environments
• Silica fume has excellent water retention and hence helps reduce waste during application by reducing bleeding
• Better overall economy as less cement is needed thanks to silica fume blending
• The problem of segregation in cement is significantly reduced

Applications of micro silica fume in various industrial processes

Micro silica fume has a wide range of industrial uses. Various industries that find it useful include hydropower projects, the construction industry, water conservation projects, bridge projects, road construction, and ports. We highlight the important uses of micro silica fume in industrial projects as follows:

Micro silica fume in the cement industry

As we highlighted above, adding micro silica fume to cement improves its physical and chemical properties. Hence it is popularly used in blending with cement for added durability and strength to construction projects.

Micro silica fume in the rubber industry

Adding silica fume to rubber brings about a more excellent resistance to shear, shrinkage, elongation, and aging properties. It also improves the dielectric properties of rubber.

Using micro silica fume for pellet binding

Powdered materials are converted into pellets to improve a material’s surface area or ease its transport and handling. Micro silica fume addition in the pellet mix can improve the binding properties of the mix.

Micro silica fume use in deposition and lining processes

Oil fields are lined using silica fume. It is also used for cementing operations.

Micro silica fume use in the fertilizer industry

Silica fume powder prevents caking in fertilizers.

Micro silica fume as an Insulation

Silica fume possesses high resistance to heat and chemicals. Hence it is used for waterproofing, coatings, linings, and other insulation processes.

Industries that use micro silica fume

Refractories industry

The addition of silica fume in refractory castables helps with greater particle packing. Its presence also means less demand for water to achieve similar flow characteristics. Micro silica fume is used in sintered, castable, and fused refractories.

Additionally, its presence ensures lower temperatures in the sintering process and forms mullite in the castable’s matrix structure. A reduction in permeability means that the final product will be immune to slag, gas, or metal penetration. Hence, adding silica fume to refractories gives a high-strength product that is non-porous and stable at high temperatures.

Concrete and Mortar industry

Concrete applications of micro silica fume can be broadly divided into three main parts: High-Performance Concrete, High strength concrete, and Shotcrete.

Micro silica fume high Performance Concrete (HPC)

As the name suggests, is an enhanced durability and high strength concrete material. It has high corrosion resistance, reduced chemical permeability, and abrasion resistance. The material also exhibits very high electrical resistivity. It is used for its abrasion resistance in floors, parking decks, highway bridges, marine structures, and overlays. The micro silica fume components also resist chemical attacks from sulfates, nitrites, chlorides, and acids.

Micro silica fume high-strength concrete

Thanks to its improved strength over conventional concrete, it allows flexibility in engineering design and architecture. With a flexural strength of 2,000 psi also has a high modulus of elasticity of around 7 million psi. For example, it can help reduce the number of columns needed to build a high-rise building. Therefore, it reduces the overall construction cost and allows more open spaces within the building structure. It can also be used to produce precast concrete structures that speed up the overall building process bringing economies in the form of time savings. High-strength concrete has a high compressive strength of 20,000 psi, and its early strength helps speed up precast construction projects.

Micro silica fume shotcrete

Silica fume shotcrete is a boon for high-strength applications, especially those with lesser space availability. It is used in mine tunnel lining, rock stabilization, and reinforcing old building structures like bridges. Its high bonding strength and chemical resistance make it best for coating piles and marine columns. Silica fume minimizes rebound losses by up to 50% as it holds the sprayed mix together while it is still wet. A thinner layer of spray can produce outstanding results (up to 12 inches) that would conventionally require 2 or 3 spray passes. Micro silica fume can be added to both dry and wet process shotcrete.

Micro silica fume mortar and grouts

Micro silica fume is used as an addition to mortar and grout mixes. It provides additional strength and adhesion among the mixed components. Vertical and overhead mortars particularly benefit from such properties of cementitious repair. Mortar can be used for the filling and reinforcement of existing structures. Silica fume leads to a reduction in cement segregation and reduces bleeding. Its properties of low permeability help plug gas and chemical leakage. Being a lightweight option, it can be used in weight-sensitive construction areas. Silica fume grouts can provide excellent hydraulic sealing in oil wells. It is also valuable for closing splits, depleted zones, and leakage repairs.

Filling and reinforcement

Silica fume in its three forms is actively used as an additive to reinforce fillers for the rubber industry. They are commercial silica, modified silica fume-waste, and silica fume-waste. They find use as fillers through a mixing process of rubber in ethylene propylene diene monomer and acrylonitrile-butadiene rubber. The resultant products exhibit improved mechanical and rheological properties. This is primarily because silica fume particles, small in size, can disperse homogeneously throughout the process mix. Another striking improvement observed is thermal stability, hardness, tensile strength, and break elongation for acrylonitrile-butadiene rubber and ethylene propylene diene monomer. Other uses as a filler and reinforcement material are in paints, unsaturated polyesters, and resins.

Micro silica fume protective coatings

Silica fume is a crucial ingredient for coatings. It brings the following characteristics in coating materials:

• Improved rheology and film formation – it provides anti-sag, anti-setting properties that help in the uniform spread of aggregates throughout the coating mixes.
• Water repellency and corrosion resistance – silica fume and anticorrosive pigments help improve water repellency and performance of the coatings.
• Resistance to scratches – silica fume introduces reinforcement in composites and elastomers, leading to more excellent scratch resistance without increasing the viscosity of the costing mix.
• Improved flow characteristics – Powder coatings require less moisture gain and good flow to stay effective at the time of application. Silica fume addition provides better storage stability and better transfer efficiency.
• Gloss control – silica fume addition can suitably modify the light reflection properties of the coatings.

Micro silica fume in wall and decorative materials

The versatile micro silica fume is the best raw material for the preparation of thermal insulation mortar and polymer mortar. It provides an effective and durable coat over aging walls. Its adhesive strength makes it an ideal material for wall decorations.

As painters like to have a smooth underlying surface for effective and efficient use of paint, they prepare rough walls using silica fume putty. It forms a layer that repels water seepage that may affect paint in the future.

Micro silica fume from Henan Superior Abrasives Co., Ltd

With more than 20 years in manufacturing micro silica fume, Henan Superior Abrasives Co., Ltd presents itself as your proffered supplier. We supply high-performance silica products from China. Your requirement for densified and undentified silica fume can be fulfilled in different configurations. Share your project needs, and we will provide you with your custom requirement. Our plants in China can furnish different silica fume configurations on request.

Get your silica fume supplied in custom 1000kg plastic woven bags and 10kg and 20 kg soluble paper bags. Plastic woven bags are also available in small supply quantities. Our high-standard materials find their use in different projects all over the world. We stay committed to delivering the best materials with prompt service.