2. Fly ash is a fine, glass-like powder recovered from gases created by coal-fired
electric power generation. Fly ash material is solidified while suspended in the
exhaust gases and is collected by electrostatic precipitators or filter bags. Since
the particles solidify while suspended in the exhaust gases, flyash particles are
generally spherical in shape and range in size from 0.5 µm to 100 µm. They
consist mostly of silicon dioxide (SiO2), aluminum oxide (Al2O3) and iron oxide
(Fe2O3).
3. Properties
Fly Ash is
• Fine powder in grey color
• Having no virtual odour
• Non – Toxic
• Non – Flammable
• Non - Explosive
Fly ash does not have any adverse health effects, however when the exposure to
fly ash is more than the recommended limits, the necessary protective equipment
for respiratory / eye / hand / skin protection to be used.
4.
5. Raw Material
Fly Ash Bricks can be produced by various types of recipes depending on
available Raw Materials. Mainly adopted recipes are as following:-
•FAL-G Bricks:
• Fly Ash: 60-80 %
•Lime: 10-20 %
•Gypsum: 5-10 %
•Sand: 10-15 %
• Fly Ash-Cement Bricks:
• Fly Ash: 60-80 %
• Sand: 20-25 %
• Cement: 8-10 %
6. Process of Manufacture
• Raw materials like Fly Ash, lime sand and gypsum or Fly Ash, Cement & Sand 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 60-80%
of fly ash, 20-25% sand and 8-10% Cement OR 60-80% of fly ash 10-20% lime, 10%
Gypsum and 10% sand, depending upon the quality of raw materials.
• After mixing, the mixture is shifted to the hydraulic/mechanical presses. The bricks
are carried on wooden pellets to the open area where they are dried and water cured
for 21 days. The bricks are tested and sorted before dispatch.
7. • Curing is done by spray water on the dried bricks. Bricks are then covered,
bricks develop themselves.
8. INSPECTION AND QUALITY CONTROL
The Bureau of Indian Standards has formulated and published the
specifications for maintaining quality of product and testing purpose.
IS : 12894 :2002. Compressive strength achievable: 60-250 Kg/c m .S q.
Water absorption: 5 – 12 %; Density: 1.5 gm/cc Co-efficient of softening
(depending upon water consistency factor) Unlike conventional clay
bricks fly ash bricks have high affinity to cement mortar though it has
smooth surface, due to the crystal growth between brick and the
cement mortar the joint will become stronger and in due course of time
it will become monolithic and the strength will be consistent.
9. POLLUTION CONTROL
• The technology adopted for making fly ash bricks is eco-friendly.
It does not require steaming or auto-calving as the bricks are cured
by water only. Since firing process is avoided. There are no
emissions and no effluent is discharged. Facial masks and dust
control equipment may be provided to the employees to avoid
dust pollution more over all the raw materials are kept under
covered by polythene sheet to avoid air pollution.
• Workmen working with Fly Ash and at the mixing area are to be
provided with protective equipment like dust masks and safety
goggles.
10. Market Demand
180 billion tones of common burnt clay bricks are consumed
annually approximately 340 billion tones of clay- about 5000
acres of top layer of soil dug out for bricks manufacture, soil
erosion, emission from coal burning or fire woods which causes
deforestation are the serious problems posed by brick industry.
The above problems can be reduced some extent by using fly
ash bricks in dwelling units.
There is good demand for fly ash bricks . The awareness among
the people is required and also same time the government has
to give some special incentives for these type of activities . The
technologies are eco friendly , Reduces solid waste and dust in
the nature. Compared to hallow brick and clay brick the cost is
reasonable . Technology for construction of wall with out
cement between the brick has been developed by GODWIN
industries , Auto Nagar, Guntur. Construction of wall with these
bricks is very easy and cost effective . Technology is
indeginiously available.
11. The need of the hour is to find wealth from wastage and eco-
friendly technologies for our progress and prosperity.
With the rise in population and increase in constructional
activities considering the improvement in the standard of
living the demand for building bricks is increasing day by day.
•Building of Fly Ash .
12. BASIS AND PRESUMPTION
• The unit will work 300 working days in a year on two shifts basis and will be able
to utilize its full capacity utilization after one year of regular production.
However, the efficiency of capacity utilization has been considered as 80%.
• Labour and wages will be as per the prescribed minimum wages.
• The rate of interest for both the fixed and working capital has been considered
as 17%.
• Margin money of around 25% of the project cost has to be arranged by the
entrepreneur.
• Operative period of the project has been considered as 10 years considering
technology obsolescence rate and period of repayment of loan.
• the cost of land, construction cost, cost of machinery and equipment, etc. has
been considered as per the prevailing market rate and as per quotation of
machinery obtained.
13. 1 Land: 0.5 acre 1,50,000
2 Building/Shed : Work Shed: 100 Sq. Mtr. @ Rs. 1500/ Per Sq. Mtr. 1,50,000
3 Office & Store: 20 Sq. Mtr. @ Rs.2500/- Per Sq. Mtr. 50,000
4 Tube well with over head tank, pipe line and other civil 60,000
construction including Boundary and Gate etc.
4,10,000
16. Resources
• 1 Truck Stone dust - 1000ft x Rs. 36 Approx =Rs 36,000/-
• 1 Truck Fly Ash – 1 ton. x Rs.600 =Rs. 600
22 ton x Rs. 600 = Rs. 13200/-
• O.P.C Cement – 1 Bag x Rs. 260 = Rs260/-
• Labor - Per Brick x Rs. 0.40 = 0.40 paisa
17. Conclusion
• Fly Ash thus holds a vast potential for improving the modern day
concrete when it comes to quality in the long term. In spite of
being an industrial waste, it can improve durability and reduce
heat of hydration.
• The prospect of fly ash still being underused even today. Thus
keeping in mind about environmental concerns and its
indispensability as a mineral admixture, the values of fly ash
should be effectively garnered .
