Definition of AAC Blocks
A - Aerated
C - Concrete
- Lightness is achieved by incorporating a large proportion of closed microscopic pores in the slurry with the help of entraining or foaming agent.
- The basic raw materials are fine-ground sand or fly ash, cement, quicklime, anhydrite or gypsum, water, and aluminum powder or paste as a rising component.
- A suitable mixture of these raw materials is poured into a mould, and the rising process starts due to the development of hydrogen gas formed by the reaction of aluminium in the alkaline suspension.
- After 20 to 40 minutes the maximum rising height is achieved and after 2.5 – 4 hours for sand based recipes the cake shows a sufficient hardness for tilting and cutting.
- In the case of fly ash based AAC the cake is ready for tilting and cutting after 1 – 2 hours.
- During 6 to 10 hours steam curing at 12 -13 bar absolute tempera(190°C) further chemical reactions take place forming a high-quality lightweight building material.
- Low thermal conductivity
- Stability to variations in temperature and humidity
- resistance to fire
- low density blocks used in multey storey building units save foundation loads in the construction.