Fly ash is a residual product of coal-fired thermal power plants. It is considered a pollutant and its disposal is a major issue. So, any use for the fly ash is highly welcome.
Bricks made by fly ash not only consume the material but also have many advantages over conventional bricks. To manufacture bricks, fly ash is mixed with sand or rock dust, cement (or lime and gypsum) in a roller mill with some additives. Bricks are formed in a hydraulic press and are cured and air-dried over days.
According to Wikipedia, the fly ash bricks have several advantages.
- It reduces dead load on structures due to lightweight (2.6 kg, dimension: 230 mm X 110 mm X 70 mm
- The same number of bricks will cover more area than clay bricks
- High fire Insulation
- Due to high strength, practically no breakage during transport and use.
- Due to the uniform size of bricks mortar required for joints and plaster reduces almost by 50%
- Due to lower water penetration seepage of water through bricks is considerably reduced.
- Gypsum plaster can be directly applied on these bricks without a backing coat of lime plaster.
- These bricks do not require soaking in water for 24 hours. Sprinkling of water before use is enough.
From The Chennai Photowalk #140 Nemam Village