This document discusses fly ash bricks as an alternative to traditional clay bricks. Fly ash is a byproduct of coal combustion in power plants, and large amounts of fly ash are produced annually in India. Fly ash bricks have several advantages over clay bricks - they are lighter, stronger, and more insulative. Various types of fly ash bricks are described, including those made from mixing fly ash with soil or adding lime, gypsum or cement. Fly ash bricks can help utilize a waste product while providing a more sustainable building material.

1. SUBMITTED BY :
AVINASH
JAISWAL
[CSJMA14001390195]
B.TECH,
IVth year
[CHEMICAL ENGINEERING]
FLY ASH BRICKS

2. CONTENTS
INTRODUCTION
CLASSIFICATION OF FLY ASH
WHY FLY ASH BRICKS?
VARIOUS TYPES OF FLY ASH BRICKS
ADVANTAGES OF FLY ASH BRICKS
APPLICATIONS
REFERENCES
1

3. INTRODUCTION
WHAT IS FLY ASH?
 ash collected from exhaust of power plants before they can fly away.
 72% of India’s power plants are coal based. These power stations generate
nearly 40 million tones of fly ash annually.
 Chemically, fly ash is a pozzolan,when mixed with lime (calcium hydroxide),
pozzolans combine to form cementitious compounds.
2

4. CLASSIFICATION OF FLY ASH
FLY ASH CAN BE CLASSIFIED INTO
TWO CLASSES:
 Class C
 Class F
3

5. CLASS C
Produced by the burning of lignite or sub
bituminous coal
Contains more than 20% lime (CaO)
Self-cementing properties
4

6. CLASS F
Produced by burning harder, older anthracite and
bituminous coal
Contains less than 10% lime (CaO)
Requires a cementing agent
5

7. WHY FLY ASH BRICKS?
Coal ash typically contains heavy metals including arsenic, lead, mercury,
chromium as well as aluminium, chlorine, cobalt and zinc.
These toxicants can cause heart damage,lung disease, respiratory distress,
kidney disease.
6

8. VARIOUS TYPES OF FLY ASH BRICKS
 Burnt clay fly ash bricks (BCFB)
 High ash content BCFB
 Flux bonded BCFB
 Fly ash lime gypsum bricks
 Fly ash cement bricks
7

9. Burnt clay fly ash bricks (BCFB):
Fly ash and local soil are mixed to manufacture BCFB.
Upto 40% additional bricks can be made using same amount of soil.
MANUFACTURING PROCESS
8
AIR DRYING TIME - 4 to 6 DAYSASH COMPOSITION - UPTO 60%

10. Flux bonded BCFB:
COMPOSITION:
Fly ash (about 80%)
Soil (about 10%)
Flux making additives/Binders
Water
DRYING TEMPERATURE: 800-10000C
MANUFACTURING PROCESS:
9

11. Fly ash lime gypsum bricks (FAL-G):
COMPOSITION:
 Fly ash (50-65%)
 Hydrated lime (8-12%)
 Stone dust (20-30%)
 Gypsum (5%)
MANUFACTURING PROCESS:
10
[1 - 2 DAYS] [15 - 21 DAYS]

12. Fly ash cement bricks:
COMPOSITION:
Fly ash (50-60%)
Stone dust (about 40%)
Portland cement (8-10%)
MANUFACTURING PROCESS:
Same as FAL-G making process.
11

13. ADVANTAGES OF FLY ASH BRICKS
NORMAL BRICKS FLY ASH BRICKS
Heavier in weight Lighter in weight
Plastering required No plastering required
Compressive strength is around 35 Kg/cm2 Compressive strength is around 100 Kg/cm2
Thermal conductivity 1.25 – 1.35 W/m2 ºC Thermal conductivity 0.90-1.05 W/m2 ºC
Water absorption 20-25% Water absorption 6-12%
12

14. APPLICATIONS
CONSTRUCTION OF BUILDING
ROAD CONSTRUCTION
FLOOR TILES MAKING
13

15. CONCLUSION
 Electricity is an essential requirement of each society and in INDIA major
part of power is produced using coal which produces fly ash.
Each one who consumes power has a moral responsibility to contribute
for its utilization.
Fly ash bricks are environment friendly and can be easily manufactured
in factory.
There is a need to shift users habit and use fly ash bricks in place of clay
bricks.
14

16. REFERENCES
http://www.ntpc.co.in
http://flyashbricksinfo.com
http://buildwithash.com
http://www.ecobrick.in
15