The document compares fly ash bricks and conventional clay bricks. Three key points: 1) Fly ash bricks were found to have higher compressive strength (8.11 MPa) than clay bricks (2.38 MPa) based on testing. Fly ash bricks also absorbed less water (10.62%) than clay bricks (16.04%) indicating lower dampness. 2) Fly ash bricks are more environmentally friendly as they utilize an industrial waste (fly ash), whereas clay brick production damages the environment. 3) The conclusion is that fly ash bricks are superior to clay bricks for construction due to their higher strength, lower dampness, lighter weight, and environmental friendliness. Fly ash bricks fulfill

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Comparative Study on Fly Ash Bricks and
Conventional Clay Bricks
Sagar Bhure1
, Bhagyashree Nagpure2
, Sneha Bhanarkar3
Students of B.E. Final Year (Department of Civil Engineering )
Kavikulguru Institute of Technology and Science, Ramtek – 441106
Abstract— Fly ash bricks are well known bricks. Fly ash bricks are slow but surely replacing
conventional clay bricks for wall construction. It is green and environmental friendly material. Fly
ash brick is real good option against clay brick. The fly ash bricks are comparatively lighter in
weight and stronger and less costly than common clay brick. This paper represents the comparison
of fly ash bricks and clay bricks. The outcome of this paper found to be the compressive strength
of fly ash bricks are more than the clay bricks and fly ash bricks absorb less water than clay bricks
that means dampness is more in clay bricks. So, we conclude that the fly ash bricks is better than
clay bricks for construction prupose.
Keywords— Clay Bricks, Fly Ash Bricks, Compressive strength, Water absorption test.
INRODUCTION
A Brick is building material used to make walls, pavements and other elements in masonry
construction. A brick can be composed of clay-bearing soil, sand and fly ash materials. Bricks are
produced numerous classes, types, materials and sizes which vary with region and time period are
produced in bulk quantities.
Based on Raw materials
1) Conventional clay bricks
2) Fly ash bricks
3) Concrete bricks
4) Sand-lime bricks
In this paper we compare two types of bricks i.e. conventional clay bricks and fly ash bricks. In
construction industries clay bricks were used in 180 billion tonnes of common burnt clay bricks
are consumed annually approximated 340 billion tonnes of clay about 5000 acres of top layer of
soil dug out for bricks manufacture clay bricks available in certain region are poor in quality and
costly, which have forced engineers to look for better material capable of reducing cost of
construction, so used of industrial waste such as fly ash for making bricks is ecologically and
economically advantageous. Fly ash is enriched with silica, is the main constituent for
conventional building materials.

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With the change of habits, choices as well as the change of society the demand of fly ash bricks
are gradually increasing day by day in the metropolitan cities. Fly ash bricks are made up of fly
ash, cement and sand. This can be extensively used in all building constructional activities similar
to that of common burnt clay bricks. The fly ash bricks are comparatively lighter in weight and
stronger than common clay bricks. Since fly ash has been accumulated as waste materials in large
quantity near thermal power plants and creating serious environmental pollution problems, its
utilization as main raw materials in the manufactured of bricks will not only creates ample
opportunities for its proper and useful disposal but also helps in environmental pollution control
to a greater extent in the surrounding area of the power plant.
Now-a-days, land gets rapidly decrease due to construction then soil is not sufficient for future
manufacturing clay bricks, these fly ash bricks fulfil the necessity of clay bricks in construction
sites.
OBJECTIVES
• To study the comparison between fly ash bricks and conventional clay bricks.
• To compare the strength of fly ash bricks with conventional clay bricks.
• To check the dampness or moisture content in the fly ash bricks and conventional clay
bricks.
LITERATURE REVIEW
Dhrumil S. Chokshi, Prof. Jayeshkumar Pitroda, Ashish H. Makwana written a paper with titled
“A Competitive Assessment on fly ash brick and clay bricks in Central Gujarat Region of India
using Chi-Square Test” through SPSS software.
The objectives of this research paper is to identify the factors affecting and make questionnaires
the performance of fly ash brick and clay brick in construction project and to study the Traders,
consultants and contractors perceptions towards the used of fly ash bricks and clay bricks in
construction project.
P. P. Gadling, Dr. M. B. Varma written paper with titled “Comparative Study on Fly Ash Bricks
and Normal Clay Brick”.
This paper presents fly ash bricks properties, manufacturing process material required for
preparing the clay bricks and fly ash bricks as per Indian Standard Code provisions. Fly ash used
as raw material replacing of clay to make fly ash bricks is an effective measure of saving land and
decreasing pollution.
CHARACTERISTICS OF MATERIALS
1) Fly Ash :-
Fly ash is the fine particulate waste material produced by pulverized coal-based thermal power
station, is an environmental pollutant, is has potential to be a resource material.

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2) Cement :-
Cement is well known binding material which is used for concreting containing of over burned
calcareous and argillaceous materials. Ordinary Portland Cement (OPC) is one of the cement
widely used in fields.
3) Fine Aggregates (Sand) :-
To improve the uniformity and workability the fine aggregates were used. It can assist to give
better binding with cement.
4) Water :-
The water is used which must customize according to general requirement. The water does not
have acidity and alkalinity the pH content should be 6 to 7.
SIZE OF BRICKS
There are different types of bricks used in construction sites. In this paper, we compare two
types of bricks, so the size of both bricks are same.
A) Clay Brick = 230mm x 100mm x 70mm
B) Fly Ash Brick = 230mm x 100mm x 70mm
Flyash
60%
Sand
30%
Cement
10%
Composition of Materials

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EXPERIMENTAL WORK
The following test performed to compared properties of fly ash bricks and conventional clay
bricks.
1)Water Absorption Test :- This test is carried out to determine the amount of water absorbed by
the bricks. i.e. To check the dampness. The clay and fly ash bricks were dried and weighed. These
were then immersed in water for 24 hours and then weighed again. When brick is immersed in
water for 24 hours it should not exceed 20% of weight of dry brick.
A) For Clay Bricks :-
Table No. 1. Water absorption for clay brick
Sr. No. Dry weight in
gm (w1)
Wet weight in
gm (w2)
Water
absorption in
gm (w2-w1)
% of water absorption
(w2-w1)/w1 ×100
1 2955 3429 474 16.04%
Figure No. 1 Clay brick
B) For Fly ash Bricks :- Initial and final weight (after 24 hrs) of bricks are shown in figure No. 2
Table No. 2. Water absorption for fly ash brick
Sr. No. Dry weight in
gm (w1)
Wet weight in
gm (w2)
Water
absorption in
gm (w2-w1)
% of water absorption
(w2-w1)/w1 ×100
1 2879 3185 306 10.62%

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Figure No. 2 Fly ash bricks
From the above test it is found that clay bricks absorb more water than the fly ash bricks. Clay
brick absorbed 16.04% of water and that of the fly ash brick absorbed 10.76% of water. Therefore,
fly ash bricks having less dampness (Less moisture contents)
2) Compressive Strength Test :- This is the main test conducted to test suitability of bricks for
construction work. This test is executed on compression testing machine. Compressive strength
was determined by applying load on the specimen using compression testing machine.
Figure No. 3 Compression test on Clay brick Figure No. 4 Compression test on fly ash brick
A) For Clay Bricks :-
Table No. 3. Compressive Strength for Clay brick
Sample Peak Load Compressive Strength
Clay Brick 1 53.5 KN 2.38 N/mm2
Clay Brick 2 56.2 KN 2.5 N/mm2
Clay Brick 3 50.8 KN 2.26 N/mm2
The average compressive strength of clay bricks found to be 2.38 N/mm2
.

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B) For Fly ash Bricks:-
Table No. 4. Compressive strength for fly ash bricks
Sample Peak Load Compressive Strength
Fly ash brick 1 184.7 KN 8.21 N/mm2
Fly ash brick 2 172.5 KN 7.67 N/mm2
Fly ash brick 189.9 KN 8.44 N/mm2
The average compressive strength for fly ash brick found to be 8.11 N/mm2
.
From the above test it is cleared that fly ash bricks are stronger in strength than the clay bricks.
MANUFACTURING PROCESS
Under this the following steps are followed for the preparation of fly ash bricks,
1) 60% Fly ash, 30% sand, 10% cement this composition taken for manufacturing bricks.
2) We prepared 20 kg of total weight of material in which 12 kg of Fly ash , 6 kg of sand and 2 kg
of cement.
3) This all materials taken in pan for mixing proper proportion of water (2.5 litres) added in it and
it mixed homogenously.
4) For mixing process, the materials are transferred into mixing tank in which it mixed
homogenously and by using belt conveyer it is transferred to automatic brick making machine in
which it is pressurised by 220 kg/cm2 pressure and brick is obtained.
5) This, brick placed at wooden pallets for 2 days after that it transferred to open space for 7-21
days curing.
6) After curing, it is tested before the dispatched.
MIXING OF FLY
ASH WITH
CEMENT, SAND
AND WATER
POURING OF
MORTAR INTO
THE MOULD OF
MACHINE
PRESSURE
APPLIED
FLY ASH
BRICKS
CURING FOR 21
DAYS
TESTED AND
DISPATCHED

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Figure 7. Pressure Applied Figure 8. Fly ash bricks
RESULT AND DISCUSSION
The following results are obtained from the various tests.
1) Compressive Strength Test :
i) For clay Brick = 2.38 N/mm2
ii) For fly ash Brick = 8.11 N/mm2
2) Water absorption Test :
i) For clay Bricks = 16.04 %
ii) For fly ash Bricks = 10.62%
We have tested both types of bricks by various experiment to compare properties of flyash bricks
and clay bricks.
These are various physical properties which compared fly ash bricks & clay bricks are as follow.
Table No. 5. Comparison of bricks
Conventional clay bricks Fly ash bricks
1) The colour of bricks varying as per the soil.
2) Uneven shape as handmade.
3) It is lightly bonded.
4) It requires plastering.
5) Heavier in weight.
6) Compressive strength is about 35 Kg/cm2.
7) It is more porous.
8) It is more costly.
9) It is not environmental friendly.
10) Water absorption is 15-25 %
11) It is less vitrified.
12) It has no dimensional accuracy.
1) Uniform colour like cement (Greyish)
2) Uniform in shape and smooth finish.
3) It is dense composition.
4) No plastering requires.
5) Lighter in weight.
6) Compressive strength is about 80 to 100
Kg/cm2.
7) It is Less porous.
8) It has less cost.
9) Environmental friendly.
10) Water absorption is 6-12 %.
11) It is more vitrified.
12) It has dimensional accuracy.

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CONCLUSION
There are different types of tests were performed, on this basis the following conclusions
obtained after the experimental study.
• The compressive strength of fly ash bricks is more than the clay ricks.
• Clay bricks absorbed more water than the fly ash bricks, since dampness and moisture
content is more in clay bricks construction.
• Fly ash bricks are lighter in weight than the clay bricks, due to this fly ash bricks reduced
the load structure.
• Fly ash bricks are environmental friendly because it used the raw material like fly ash
which can cause the pollution.
• Now a days, land gets rapidly decrease due to construction then soil is not sufficient in
future for manufacturing clay bricks these fly ash bricks fulfil the necessity of clay bricks
in construction sites.
Therefore, after all this experimental work, we conclude that, Fly ash bricks are more superior
than clay bricks for construction works.
REFERENCES
1) Dhrumil S. Chokshi, Prof. Jayeshkumar Pitroda, Ashish H. Makwana, “A Competitive
Assessment on fly ash brick and clay bricks in Central Gujarat Region of India using Chi-
Square Test through SPSS software”. (May 2014)
2) P. P. Gadling, Dr. M. B. Varma, “Comparative Study on Fly Ash Bricks and Normal Clay
Brick”.