Microsilica in Concrete

Microsilica is important factor in concrete as it helps to increase strength and durability of concrete. It is providing more uniform distribution and high volume for hydration process. Silica fume is known as microsilica and is a composition of silicon dioxide, carbon, silicon carbide and oxides of alkaline (earth) metals. Major content in silica fume is silicon dioxide. It is a by-product of the reduction of high-purity quartz with coal in electric furnaces in the production of silicon and ferrosilicon alloys.

There are three types of microsilica

Ø Powdered microsilica

Ø Condensed microsilica

Ø Slurry microsilica

Microsilica reduces segregation possibilities, bleeding. It reduces the workability and consistency of concrete. It will help in bonding. It is sulphate and chemical resistance. It improves compressive strength, flexural and tensile strength.

It is grey, white and black in colours. It is in powdered form.

Advantages

Ø It is used to reduce thermal cracking which is cause by heat of cement hydration.

Ø It improves its durability against sulphate attack and acidic water.

Ø It is cost effective as product is cheap.

Ø It will help to reduce efflorescence as it gives refined pore structure.

Ø It will reduce the early temperature rise in structure.

It is used in silica fume waterproof concrete, high strength concrete, shotcrete, elastomeric, polymer, refractory, ceramic and rubber applications.

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