Is microsilica an admixture?
Microsilica is a mineral admixture composed of very fine solid glassy spheres of silicon dioxide. Frequently called condensed silica fume, microsilica is a by-product of the industrial manufacture of ferrosilicon and metallic silicon in high-temperature electric arc furnaces.
What is pozzolanic admixture?
Pozzolanic or Mineral admixtures refer to the finely divided materials which are added to obtain specific engineering properties of cement mortar/concrete. Popular examples of mineral admixtures are silica fume, fly ash, blast furnace slag etc.
What is cementitious admixture?
Concrete admixtures are natural or manufactured chemicals or additives added during concrete mixing to enhance specific properties of the fresh or hardened concrete, such as workability, durability, or early and final strength.
What are the two types of admixtures?
They are: Type A: Water-reducing admixtures. Type B: Retarding admixtures. Type C: Accelerating admixtures.
Is microsilica a code?
Basic Details
| IS Number : | IS 15388 : 2003 |
|---|---|
| Technical Committee : | CED 2 ( Cement And Concrete ) |
| Language : | English |
| ICS Code : | ICS 91.100.15 |
| Product Id : | 15388 |
How is microsilica made?
Silica fume, also known as microsilica, is an extremely fine noncrystalline polymorph of silica and is produced in electric arc furnaces (EAFs) as a by-product of silicon and ferrosilicon alloy production. As just mentioned, silica fume arises as a by-product of silicon or ferrosilicon alloy formation in an EAF.
What are the types of pozzolans?
The most common natural pozzolans used in concrete applications today include calcined clay, calcined shale and metakaolin. Other types of natural pozzolans that are used less in modern applications include volcanic ash, volcanic glass (pumicite and obsidian) and rice husk ash, among others.
How do concrete admixtures work?
Admixtures work by one or more of the following actions: Chemical interaction with the cement hydration process, typically causing an acceleration or retardation of the rate of reaction of one or more of the cement phases.
Why admixture is added to concrete mixture?
Producers use admixtures primarily to reduce the cost of concrete construction; to modify the properties of hardened concrete; to ensure the quality of concrete during mixing, transporting, placing, and curing; and to overcome certain emergencies during concrete operations.
What is an air-entraining admixture?
Air-Entraining Admixtures and What They Do: Air-entraining admixtures facilitate the development of a system of microscopic air bubbles within concrete during mixing. They increase the freeze-thaw durability of concrete, increase resistance to scaling caused by deicing chemicals, and improve workability.
Which type of admixture is used in RMC?
10. Anti-washout Admixtures. Anti-washout admixtures are used in concrete especially for under water concrete structure. It protect the concrete mix from being washed out under water pressure.