Several admixtures are used in concrete to improve its properties. One type of admixture is pozzolans, which enhance the quality and workability of concrete through chemical reactions.
Pozzolanic Admixtures
Pozzolans are materials that, when mixed with concrete, react with the calcium hydroxide produced during the hydration of cement to form additional cementitious compounds. This reaction leads to a denser, stronger, and more durable concrete. According to the provided reference, some common pozzolanic admixtures include:
- Fly ash: A byproduct of coal combustion in power plants.
- Silica fume: A very fine powder collected from the production of silicon and ferrosilicon alloys.
- Rice husk ash: The ash remaining after burning rice husks.
- Metakaolin: A calcined clay that is produced by heating kaolin clay.
These materials are used as admixtures to enhance various properties of concrete such as:
- Increased strength
- Improved durability
- Enhanced workability
- Reduced permeability
- Lower heat of hydration
- Reduced cost
These benefits of using pozzolanic admixtures make them valuable components in modern concrete production. Therefore, the admixtures fly ash, silica fume, rice husk ash and metakaolin are used in concrete.
