METAKAOLIN Meaning and
Definition
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Metakaolin is a fine powder that is derived from the controlled calcination of kaolin clay. It is a highly reactive aluminosilicate material, known for its pozzolanic properties. Metakaolin is primarily used in the construction industry as a supplementary cementitious material in cement and concrete.
Metakaolin undergoes a process called calcination, wherein kaolin clay is heated to temperatures between 600 to 800 degrees Celsius. During this process, the crystal structure of the kaolin clay is transformed, resulting in the formation of metakaolin. This transformation leads to the activation of the reactive amorphous, non-crystalline phase of the clay.
The main characteristic of metakaolin is its high content of reactive amorphous alumina and silica, which makes it highly effective in improving the performance of cementitious materials. When metakaolin is used as an additive in cement or concrete production, it enhances the properties of the final product, including increased compressive strength, reduced permeability, and improved durability.
Due to its high reactivity, metakaolin also helps to mitigate the negative environmental impact of cement production. Its usage can reduce the amount of cement needed, resulting in lower greenhouse gas emissions and energy consumption. Additionally, metakaolin has the ability to optimize the performance of concrete under extreme conditions, such as high temperatures or chemical exposure.
In summary, metakaolin is a calcined form of kaolin clay that exhibits pozzolanic properties. It is widely used in the construction industry to enhance the performance and durability of cementitious materials while minimizing environmental impact.
Etymology of METAKAOLIN
The word "metakaolin" is derived from the combination of two terms: "meta" and "kaolin".
The term "meta" derives from the Greek word "meta", meaning "beyond" or "transformation". It is often used as a prefix to indicate a change or alteration. In the context of metakaolin, "meta" signifies the transformation or alteration of the starting material, which is kaolin.
Kaolin refers to a type of clay mineral that is known for its white color and fine particle size. It is named after the Chinese region Kao-Ling, where it was originally discovered and extensively used in pottery and porcelain production.
When kaolin is subjected to high temperatures (around 500-800°C), it undergoes a process called "metamorphism" or "calcination". This thermal treatment transforms the kaolin into metakaolin by removing chemically bound water and altering the crystal structure.
