This document discusses the use of fly ash as a mineral admixture in concrete. It begins with an introduction to mineral admixtures and then focuses on fly ash, describing its composition, types (Class F and Class C), and how it improves the properties of fresh and hardened concrete. Specifically, fly ash reduces heat of hydration, increases strength over time, improves durability, and reduces permeability. The document provides an example mix design and test results showing comparable compressive strengths between concrete with and without fly ash. It concludes that fly ash is an indispensable mineral admixture that improves long-term concrete properties while also providing environmental benefits.

1. MINERAL ADMIXTURES
(FLY ASH)
PRESENTED BY
ZUBAIR AHMAD DAR
(1EP13CV110)
Under the guidance of
Mr.VENKATESHA N
Asst Professor,
Dept of Civil Engineering,
East Point College of Engineering &
Technology

2. 1.INTRODUCTION
2.WHY MINERAL ADDITIVES
3.TYPES OF MINERAL ADDITIVES
4.FLY ASH AND IT’S TYPES
5.EFFECT OF FLY ASH ON PROPERTIES OF FRESH
CONCRETE
6.EFFECT OF FLY ASH ON HEAT OF HYDRATION
7.EFFECT OF FLY ASH ON HARDENED CONCRETE
8.DURABILITY OF CONCRETE
9.CONCLUSION
10.REFERENCES

3. Admixtures are ingredients other than basic
ingredients cement,water and aggregates that are added
to concrete batch immediately before or during mixing
to modify one or more of the specific properties of
concrete in fresh and hardened state.
 Added in small quantity either in powder or in liquid
form.
 Combination is used when more than one property to
be altered.
 Admixture is used to modify the properties of
ordinary concrete so as to make it more suitable for any
situation.
 Use of Ready mix(RMC)has really promoted the use
of admixtures in india,in recent times.

4. WHY MINERAL ADDITIVES
Improves many qualities of concrete,such
as:
Lower the heat of hydration and thermal
shrinkage.
Increase the water tightness.
Reduce the alkali-aggregate reaction.(gel
expansion causes cracking in the concrete)
Improve workability.
Lower costs.

5. TYPES OF MINERAL ADMIXTURES
1.Natural Pozzolans
Clay and Shales
Opalinc Cherts
Diatomaceous Earth
Volcanic Tuffs and Pumicites

6. 2.Artificial Pozzolanes
Fly ash
Blast Furnace Slag
Silica Fume
Rice Husk ash
Ground Granulated Blast Furnace Slag
(GGBS)
Metakaoline
Surkhi

7. Fly ash is finely divided residue resulting from the
combustion of powdereed coal and transported by the flue
gases and collected by electrostatic precipitator .
Fly ash is the most widely used pozzolanic material all
over the world.
In the real world of modern concrete,fly ash is as
essential ingredient of the mixture as are portland
cement,aggregate,water and chemical admixtures.

8. In most concretes,fly ash is used in large amounts
(by volume) than portland cement,and therefore it is
not an admixture i.e, an addition to the mixture.
Concrete without fly ash and chemical admixtures
should only found in museum showcases.
Fly ash was first used in large scale in the
construction of Hungry Horse Dam in America in the
year 1948 in the approximate amount of 30 percent
by weight of cement.
In India,fly ash was used in Rihand Dam
construction replacing cement upto about 15 percent
by weight of cement.

9.  In recent time,the importance and use of fly ash in
concrete has grown so much that it has almost
become a common ingredient in concrete,particularly
for making high strength and high performance
concrete.
Extensive research has been done all over the world
on the benefits that could be accrued in the utilisation
of fly ash as a supplementary cementitious
material.High volume fly ash concrete is a subject of
current interest all over the world.
The use of fly ash as concrete admixture not only
extends technical advantages to the properties of
concrete but also contributes to the environmental
pollution control.

10. Cement is the backbone for global infrastructural
development.Production of every tone of cement
emits carbon dioxide.Expressing it in another way,it
can be said that 7% of the world’s carbon dioxide
emission is attributed by portland cement industry
as per research done.
One of the practical solutions to economise cement
is to replace cement with supplementary
cementitious materials like fly ash.
In India,the total production of fly ash is more than
100 million tons.But our utilisation of fly ash is only
about 20% of production.Therefore,the use of fly ash
must be popularised for more than one reason.

11. In india, fly ash was used for the first time in
constructoin of Rihand Irrigation Project(fig. below),
UP in 1962,replacing cement up to about 15%.

12. FLY ash images

13. Class F
Fly ash normally produced by burning anthracite or
bituminous coal, usually has less than 5% CaO. Class F fly
ash has pozzolanic properties only.
 Class C
Fly ash normally produced by burning lignite or sub-
bituminous coal. Some class C fly ash may have CaO
content in excess of 10%.In addition to pozzalanic
properties,class C fly ash also possess cementations
properties.

14. Concrete using fly ash is generally reported to show
reduced segregation and bleeding and to be more
satisfactory than plain concrete when placed by pumping.

16. Replacement of cement by fly ash results in a
reduction in the temperature rise in fresh Concrete.
This is particular important in mass concrete where
cooling,following large temperature rise, can lead to
cracking.

18. Contributes to the strength of concrete due to
its pozzolanic reactivity.
Continued pozzolanic reactivity concrete
develops greater strength at later age not at initial
stage.
Contributes to making the texture of concrete
dense, resulting in decrease of water permeability
and gas permeability.

19. Concrete containing good quality fly ash shows dense
structure which offers high resistivity to the infiltration
of deleterious substances.
 A point for consideration is that the pozzolanic
reactivity reduces the calcium hydroxide content, which
results in reduction of passivity to the steel
reinforcement and at the same time the additional
secondary cementitious material formed makes the
structure dense, and there by gives more resistance to
the corrosion of reinforcement.

20. It is also recognized that the addition of fly ash
contributes to the reduction of the expansion due to
alkali-aggregate reaction.
 In conclusion it may be said that although fly
ash is an industrial waste, its use in concrete
significantly improve the long term strength and
durability and reduce heat of hydration. In other
words good fly ash will be an indispensable
mineral admixture for high performance
Concrete.

21. Many high-rise buldings
Industrial structures
Water front structures
Concrete roads
Roller compacted concrete dams.

22. MATERIAL:
Cement:Ordinary Portland Type-1 cement was
used.
Fine Aggregate:Manufactured sand.
Coarse Aggregate:Lime stone crushed stones of
size 12.5mm and 20mm.

23. Mineral admixture fly ash was used.
M20 grade was used (1:1.5:3).
The water cement ratio as 0.55

33. Fly ash
content (%) Fly ash(kg)
Cement
(kg) Sand(kg) Aggeragate(kg)
0 0 7.55 11.25 22.5
30 2.25 5.25 11.25 22.5
Table-1:Material Mixing Proportions

34. Fly Ash
Content
(%)
w/c
ratio
slump
value
(mm)
compressive strength
(Mpa) after 14 days
0 0.55 50 19.21
30 0.55 60 18.95
Table-2: TEST RESULTS

35. Compresive strength of concrete cube of
size(150x150x150mm) with zero percent flyash
at w/c ratio 0.55 is 19.21 Mpa.
Compressive strength of concrete cube of
same size and same w/c ratio as mentioned
above with 30% of fly ash by weight of cement
is 18.95 Mpa.

36. REFERENCES
1.Concrete technology(theory and practice)-MS Shetty
2.P. Chindaprasirt, T. Chareerat, and V. Sirivivatnanon,
Workability and strength of coarse high calcium fly ash
geopolymer, Cem. Concrete.
3.Alaa M Rashad, A brief on high volume fly ash as
cement replacement.
4.Vanita Aggarwal,S.N.Gupta and S.N.Sachdeva(HIGH
VOLUME FLY ASH CONCRETE)
5.http://flyash.com