Pozzolanic materials are siliceous and aluminous materials, which do not possess any cementitious properties but form cementitious compounds by reacting with lime in the presence of water. It is volcanic ash containing about 80% clay.
The use of pozzolanic materials provides the following improvements:
- Improves workability
- Lowers the heat of hydration
- Assists in early setting and hardening of the mortar
- Reduces shrinkage
- Improves hydraulic properties and resistance to chemical attacks.
Naturally available pozzolanic materials are clay and shale, diatomaceous earth, volcanic tuffs and pumicites. Artificially available pozzolanic materials are fly ash, blast furnace slag, silica fume, rice husk ash, metakaoline and surkhi.
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