This document discusses the reuse of fly ash from coal power plants. Fly ash is a byproduct of coal combustion that can be used in concrete production as a substitute for cement and sand, for construction fills and road bases, and in agriculture and soil amendments. Using fly ash in concrete reduces costs and improves strength, permeability, and durability. Fly ash bricks are also discussed as an alternative to clay bricks that is more environmentally friendly through waste reuse. Overall fly ash utilization provides environmental and economic benefits.

3. NAME:
1. DESAI KALYANI A.
2. MAGDUM SONAL P.

5. INTRODUCTION
 Electricity is the key for development of any country. Coal
is a major source of fuel for production of electricity in many
countries in the world.
In the process of electricity generation large quantity of fly
ash get produced and becomes available as by-product of
coal-based power stations.
It is a fine powder resulting from the combustion of
powdered coal – transported by the flue gases of the boiler
and collected in Electrostatic Preceptors

6. FLY ASH REUSE
 Concrete production, as a substitute material for
Portland Cement and Sand
 Embankments and other structural fills (usually
road construction )
 Grout and Flowable fill production
 Waste stabilization and solidification
 Cement clinkers production
 Mine reclamation
 Stabilization of soft soils
 Road sub base construction
 Loose application on roads and parking l

7. Different Modes Of Fly Ash Utilization :
Building Materials
Mine Filling
Road and Pavement Construction
Cement Blending
Agricultural / Soil Amendment
Concrete and Mortar
Light Weight Aggregate
Floor and Wall Tiles
Paint Industry, etc.

9. FLY ASH FOR CEMENT CONCRETE
 Tetracalcium alumino-ferrite forms hydration product similar to those of C A,
with iron substituting partially for alumina in the crystal structures of ettringite
and monosulpho-aluminate hydrate.
 Above reactions indicate that during the hydration process of cement, lime is
released out and remains as surplus in the hydrated cement. This leached out
surplus lime renders deleterious effect to concrete such as make the concrete
porous, give chance to the development of micro- cracks, weakening the
bond with aggregates and thus affect the durability of concrete.
 If fly ash is available in the mix, this surplus lime becomes the source for
pozzolanic reaction with fly ash and forms additional C-S-H gel having similar
binding properties in the concrete as those produced by hydration of cement
paste. The reaction of fly ash with surplus lime continues as long as lime is
present in the pores of liquid cement paste.
The process can also be understood as follows:
CONTINUE……..

10. Ordinary Portland Cement + Water
Surplus
Lime
Fly Ash
Additional
Cementious Material
Cementious Material
CONTINUE…..

11. ADVANTAGE OF FLY ASH IN CEMENT CONCRETE
 Reduction in heat of hydration and thus reduction of thermal
cracks and improves soundness of concrete mass.
 Improved workability / pumpabilty of concrete
 Converting released lime from hydration of OPC into
additional binding material – contributing additional strength to
concrete mass.
 Pore refinement and grain refinement due to reaction between
fly ash and liberated lime improves impermeability.
 Improved impermeability of concrete mass increases
resistance against ingress of moisture and harmful gases
result in increased durability.
 Reduced requirement of cement for same strength thus
reduced cost of concrete.

12. USE OF FLY ASH IN
CONSTRUCTION

14. FLY ASH BRICKS
 A well-proven building material and can be used as
an alternate of burnt clay bricks.
 Bricks of comparable strength can be
manufactured.
 Bureau of India Standards have issued code
IS:12894-2002 for ash bricks.
 Use of fly ash bricks has been incorporated in
CPWD specifications.
 In Delhi schedule of rate (DSR), items for these
bricks have been provided.

15. ADVANTAGES OF FLY ASH BRICKS
 Fly ash bricks are produced without/with frog.
 The bricks are uniform in shape and size, therefore,
require less mortar in brick work.
 Plaster thickness required will be less compared to
clay bricks, thus saving cement mortar.
 These bricks are environment friendly as :
It uses fly ash, which is by-product of thermal
power stations.
Saves agricultural land which is used for
manufacturing clay bricks.
Less energy intensive compared to clay bricks
and helps in keeping clean environment.

16. DISADVANTAGES OF FLY ASH BRICKS:
 Bonding is lower due to smooth finish, this can be
easily corrected by using a cement : sand mortar of
1:4 and proper curing. Also the quality of sand
needs to be checked.
 Poor quality and outlook in color without plastering.
 Weak binding strength of gradients.
 Limitation of size. Only modular size can be
produced.
 Large size will have more breakages.
 Weak binding with cement mortar when used in
making walls.

17. SALIENT FEATURES
 Environment eco friendly.
 Energy efficient product.
 Products stronger than woods.
 Weather resistant and durable.
 Termite, Fungus, rot and Rodent resistant.
 Fire resistant.
 Cheaper than natural wood.
 Less maintenance cost.
 Fruitful utilization of industrial wastes such as fly
ash.

18. OTHER BENEFITS OF USING FLY ASH
 Reduces soil erosion by replacing top soil as
ingredients for most construction mixes.
 Reduces pollution measure by re-use of wastes.
 Reduces the amount of greenhouse gases being
added to atmosphere.
 Hydrophobic nature helps in proper drainage off of
water from roads and structures.
 Production of crude oil from polyethylene.
 Also used in sewage treatment and generation of
bio-fuel as an alternate source of energy resources.

19. CONCLUSION
 Fly ash has been proved to be a useful material for
many application. Policy framework and national
strategy can make it possible to utilize all fly ashes in
gainful manner
 It would mitigate the environmental threat, generate
employment and industrial wealth conserve mineral
resources, provide sustainable construction and
agricultural including forestry and cleaner environment
 Its product including agriculture produce grown on fly
ash within safe limits
 Thus, this may be used on large scale with no
consequential impact on human health as well as
environment.