Silica Fume
• The high surface area of silica fume particles is an important factor affecting the reactivity of the particles and plays very important role in improving the physical and chemical properties of concrete. Silica fume addition benefits concrete in two ways, firstly, the minute particles physically decrease the void space in the cement matrix, and secondly, silica fume works as very effective pozzolan, it chemically reacts to produce calcium silicate hydrate, which results in the increase of compressive strength of concrete.
• The chemical composition of silica fume depends on the chemical composition of raw materials used in the furnace. The silica content of silica fume is generally higher than 85%. The other oxides such as alumina, ferric, calcium oxide and alkali content of silica fume is relatively low. The magnesium oxide is also low, while the carbon content varies from 0.5% to 1.5% and usually remains less than 2%.
Specifications
• Infinitesimal particles (1.0 microns).
• It is having spherical shape and an amorphous glass structure (amorphous).
• It has high content of silicon oxides is 97%.
• It is a very active Bozulunih material, especially when added with cement.
The most important advantages of concrete after adding the silica Fume by the used mixture type:
• Improving the physical and chemical properties of the concrete mixture whether in the Teflon case or hardened case.
• The particles size represents (100/1) of the granulated cement. Thus, it fills the voids between the particles of cement, which reduces permeability rates, which works on the formation of a dense and coherent concrete mixture leading to increases the rate of pressure resistance to (1000 kg / cm 2).
• Preventing the phenomenon of water permeability because it has a high affinity to water absorption.
• Preventing the phenomenon of concrete carbonation because mainly corrosion of the reinforcing steel.
• Preventing the emergence of a white crust on the known concrete surface as the White rash (efflorescence) because they react with the hydrated Lime to produce the hydrated calcium silicate.
• The Silica fume of concrete has a greater resistance to the penetration of chloride ions into the concrete.
• It increases the resistance to bending and tensile strength which it up to 30%.
• Graining the effective resistance against chemicals and solvents.
• The Silica fume concrete is more resilient to shocks and loads from the ordinary concrete.
• Because of the significant reduction in the degree of permeability of Silica fume concrete, it has proven to be effective when used in the water installations and bridges.
Packing
• Densified & packed in jumbo bags each of 1000 – 1500 kg.
• Bulk in silo trucks.