What is metakaolin used for?
Metakaolin is a dehydroxylated form of the clay mineral kaolinite. Metakaolin is commonly used in the production of ceramics, but is also used as cement replacement in concrete. Metakaolin has a smaller particle size (∼1–2 μm) and higher surface area compared with portland cement, but a larger particle size than SF.
Why is metakaolin used in concrete?
Metakaolin is a pozzolan, probably the most effective pozzolanic material for use in concrete. This results in improvements to resistance of the hardened concrete to attack by sulfates, chloride ions and other aggressive substances, such as mineral and organic acids.
What is the difference between kaolin and metakaolin?
Kaolin adsorbs calcium hydroxide not only at the edges of the clay particles but also onto the basal faces. Metakaolin shows high pozzolanic activity, which provides the quick formation of hydrated phases at the interfaces between metakaolin and lime solutions.
Is clay a pozzolan?
One possible source for a pozzolan is calcined clay. Natural pozzolans in the form of calcined earths blended with lime have been used to produce cementitious materials for thousands of years [3], [4].
What is metakaolin based geopolymer?
Metakaolin-based geopolymers are aluminosilicate materials that can be used as cationic dye adsorbents in aqueous system treatment. Our aim in this paper is to study the ability of geopolymer powder produced from metakaolin and alkaline activators to act as an adsorbent to remove methylene blue (MB).
Is metakaolin a code?
IS 456:2000 recommends usage of metakaolin in concrete.
What is Surkhi in construction?
Surkhi is an artificial pozzolanic material made by powdering bricks or burnt clay balls. Surkhi is used for making waterproof cement mortars and concrete. They also make the concrete more resistant to alkalis and salt solutions.
What is pozzolana made of?
The modern definition of pozzolana encompasses any volcanic material (pumice or volcanic ash), predominantly composed of fine volcanic glass, that is used as a pozzolan.
What is natural pozzolan?
Natural pozzolans include rocks of volcanic origin (e.g. vitreous rhyolites from the Rocky Mountains in the USA or German and Turkish trasses), as well some sedimentary clays and shales. Some may be used as they are, while others undergo a process of thermal activation (e.g. calcined clays).
How do you make Metakaolin?
Metakaolin was prepared by calcining kaolin at 750 °C for 24 h. Chemical composition of the kaolin as measured by XRF is as follows (mass%): SiO2 46.36, Al2O3 37.6, LOI 13.5, Fe2O3 0.94, TiO2 0.8, MgO 0.24, K2O 0.22, CaO 0.2, Na2O 0.13, SO3 0.07.
How is geopolymer concrete made?
Rather than hydrating Portland cement, geopolymer concrete is made by mixing the sand and aggregate with fly ash or slag, and then activating it with an alkali such as sodium hydroxide. “It is a similar price to standard concrete and its structural properties and the mechanics of strength gain are well understood.