Micro Silica (Silica Fume)

Microsilica (silica fume) is a by-product from silicon metal or ferrosilicon industries, is an amorphous silicon dioxide – SiO2. This product reacts chemically with the calcium hydroxide in the cement paste which yields a calcium silicate hydrate gel that significantly enhances strength and durability. The super fine microsilica fills the voids between cement particles creating a very dense, less permeable concrete.

Physical characteristics:

Color: grey or grey white powder

Bulk density: 320-700 kg/m3

Chemical composition:
Items SiO2 Al2O3 Fe2O3 MgO CaO Na2O Moisture
Content
85~98%
1.0±0.2%
0.9±0.3%
0.7±0.1%
0.3±0.1%
1.3±0.2%
<1%
Fineness:

the fineness of the silica fume is less than 1μm, and the average particle size is 0.1 – 0.3 μm, and the specific surface area is 20 – 28 m2/g. The fineness and specific surface area are about 80-100 times of cement and 50-70 times of fly ash.

Maxtech’ s Micro Silica supplies will be as per QCS 2014 (ASTM C1240):

SiO2: >/= 92%

LOI: <6

Moisture Content: <1%

Activity Index at 7 days: > 105%

Application & Benefits of Microsilica (Silica fume):

In concrete:

The micro silica fume powder can be well filled in the cement particle space and make the slurry denser, mainly in the following:

  • Increase strength
  • Increase the density
  • Frost resistance
  • Early strength
  • Anti abrasion and anti-cavitation resistance
In Refractories:
  • Microsilica powder is widely used in the refractory industry. It has an important effect on the improvement of the amorphous refractory.
  • The production of amorphous and shaped refractory products as additives makes the strength and high temperature performance greatly improved.
Other Application:

Elastomers/Polymers

Fertilizer

Oil & Gas Well

Fiber Cement

Shotcrete

Wallboard

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