Fly ash Bricks | Formula

fly ash bricks



Fly Ash bricks are alternative to burnt clay bricks in the construction sector in India. Fly ash is mixed with two other ingredients available as industrial byproducts:
Lime from the acetylene industry, and
Gypsum from chemical plants.
This is proving to be a revolutionary invention that produces bricks without the sintering process and consequently no greenhouse gases are emitted. The ultimate product is none other than FaL – G Brick which is well qualified as emission-abating project to receive the benefits of carbon credits.

  • 73% power generated in INDIA is from Thermal Power and 90% of it is coal based.
  • Ash content is 27% to 42% of the coal used.
  • Increase in FLYASH generation has risen from 4 crore to 11crore ton in the last decade and will rise to 1100 crore ton in coming decade. 
  • Approximately 10,000 hectares of top soil is being lost every year for brick manufacturing and road construction.
  •  If we continue in this format, very soon, we will not have sufficient soil to produce our minimum required food.
  • Ministry of Environment & Forest (MoEF) Had issued a Gazette Notification on 14 Sep 1999 , Stipulating that no person shall be permitted to manufacture clay bricks or tiles or blocks for use in construction activity without at least 25% of ash (fly ash, bottom ash, or pond ash on weight to weight basis), within a radius of 50 Km from coal or lignite based thermal power plants in INDIA
  • Ministry of Environment & Forest Had amended the Gazette Notification on 27 Aug 2003 making it compulsory to use fly ash for manufacturing building material by increasing the radius from 50 Km to 100 Km

Fly ash bricks are nowadays mostly used for construction and gaining its popularity over builders and engineers because of its high strength, uniformity and less consumption of mortar plastering. Above to this it is eco friendly bricks which saves environmental damage caused by burnt clay bricks and saves top agricultural soil which was the main raw material in the burnt clay bricks.


a) Process of Manufacture:
Fly ash, Hydrated lime, Quarry dust and gypsum are manually fed into a pan mixer where water is added in the required proportion for intimate mixing. The proportion of the raw material is generally in the ratio  depending upon the quality of raw materials.



fly ash






Quarry Dust

After mixing, the mixture is shifted to the hydraulic Brick Making machines. The bricks are carried on wooden pellets to the open area where they are dried and water cured for 14 days. The bricks are tested and sorted before dispatch.

b) Quality Control and Standards:
        The Bureau of Indian Standards has formulated and published the following specifications for maintaining quality of the Flyash Brick  and testing purpose.

Quality and Standards :
IS 12894:1990 Specification for Flyash Lime bricks