User:Microsilicon

Microsilica and Concrete(Concrete Mixing, Oil well grouting, Refractory)

Silica fume, also known as micro silica,it is a very fine pozzolanic material, composed of amorphous silica produced by electric arc furnaces as a byproduct of the production of elemental silicon or ferro silicon alloys. Silica fume can be used in a variety cementitious products such as concrete,grouts,and mortars as well as elastomer,polymer,refractory,ceramic and rubber applications.

Advantages from use of microsilica:

Strength gain Microsilica can ensure the compressive strength, much more exceeded the strength of normal concretes, and this is an aggregate strength that is the limiting factor here. At the application of natural aggregates the strength more than 150 N/mm2 is reached, and at the application of special high-strength aggregates, the strength of 300 N/mm2 can be reaches. Penetrability

The effect of interstices filling created by pozzolanic spherical microparticle, favours to low the concrete capillary porosity and penetrability. Practically the impenetrable concrete can be received at reasonable microsilica content and rather low type I cement content. As microsilica effects more the penetrability than the strength, the concrete with microsilica will be always less permeable, than the concrete in type I cement of the same strength. Protection of reinforcement

In Norway and Sweden the studies of concrete buildings at the age of 12 years showed that high-qaulity concretes with microsilica are not less stable to be carbonized than the concretes of the same strength on ordinary Portland cement and prevent much better the penetration of salt water chlorides (the great quantity of laboratory measurements of reinforcement corrosion are made. It is safe to say that on condition of proper curing the capacity of concrete with microsilica to protect steel reinforcement will not differs a lot as compared with concrete of the same strength on ordinary Portland cement).

Freeze-thaw durability The low permeability and augmented cement stone density provide the good freeze-thaw durability of microsilica concrete. The microsilica is combined with the air-entraining agents. In fact the stable rheological structure of plastic microsilica concrete reduces the loss of the entrained air at transportation and vibration.

Chemical influence It is known that the low permeability and low free lime content improve the concrete resistance to influence of aggressive chemicals. The microsilica concrete is possessed of all these features and shows the excellent resistance to many foreign substances. The long-term field tests in Norway showed that it was compared with sulfate resistant Portland cement by its resistance to sulfates. Economy

The application of condensed microsilica in the mass construction allows to save 40% of cement not worsening the concrete characteristics and reducing the heat energy at heat and humidity processing of articles.