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SAMARTH ENGINEERING COLLEGE,
HIMATNAGAR
PROJECT :- APPLICATION OF FLYASH FOR PARTIAL REPLACEMENT OF CEMENT IN CONCRETE
RATHOD PRITESH V. (100880106039)PATEL AKASH K . (100880106013)
PATEL VISHAL R. (100880106010)
INTRODUCTION OF FLY ASH Fly ash is one of the residues generated in combustion, and
comprises the fine particles that rise with the flue gases. Ash
which does not rise is termed bottom ash. In an industrial
context, fly ash usually refers to ash produced during
combustion of coal.
Fly Ash Concrete
In the 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.
In India alone, we produce about 75 million tons of fly ash
per year, the disposal of which has become a serious
environmental problem.
Fly Ash Concrete
It was estimated that global production of cement is about
1.3 billion tons in 1996. Production of every tone of
cement emits carbon dioxide to the tune of about 0.87 ton.
Expressing it in another way, it can be said that 7% of the
worlds carbon dioxide emission is attributable to Portland
cement industry.
Amount of Fly Ash Generated in India:
The fly ash generation is increasing in such a proportion that it
will not be possible for the cement industry alone to utilize the
same. New avenues of gainful utilization of fly ash have to be
found and promoted.
Plan Period Terminal Area
Power Generation
(MW)
Coal
(million tons)
Fly Ash
(million tons)
8th
plan 1996-97 50,000 210 80
9th
plan 2001-02 87,000 285 110
11th
plan 2006-07 1,16,400 400 140
11th
plan 2009-10 1,38,300 500 175
12th
plan 2011-12 1,68,500 680 210
13th
plan 2012-2013 1,98,700 826250
CHARACTERSTICS OF FLY ASH
There are two type characteristics of fly ash
1. Physical characteristics of fly ash.
2. Chemical characteristics of fly ash
TYPES OF FLY ASH I) Class F
II) Class C
Class F Type Fly ash normally produced by burning anthracite or
bituminous coal, usually has less than 5% CaO. Class F
fly ash has pozzolanic properties only.
In other word, the burning of harder, older anthracite and
bituminous coal typically produces Class F fly ash. This
fly ash is pozzolanic in nature, and contains less than 20%
lime (CaO).
Class C Type Fly ash normally produced by burning lignite or sub-
bituminous coal. Some class C fly ash may have Ca O
content in excess of 10%. In addition to pozzolanic
properties, class Cfly ash also possesses cementitious
properties.
Class C fly ash generally contains more than 20% lime
(Ca O). Alkali and sulfate (SO4) contents are generally
higher in Class C fly ashes.
Advantages of fly ash in concrete:- Reduced water content for a given workability or
improved workability at the same water content.
The rate of bleeding is reduced while workability is
increased.
Improved long term strength and durability performance.
Lower shrinkage and porosity as a result of the lower
water content.
Lower permeability and better resistance to sulphate
attack.
Disadvantages of fly ash in concrete:-
Concrete changes from a liquid to a solid a few hours after
pouring, but the curing process may take much longer.
Fly ash admixtures can lengthen the time it takes for
concrete to set.
Fly ash reduces the amount of air entrainment, and
concrete mixtures high in fly ash often require more air-
entraining admixture.
It is more difficult to control the colour of concrete
containing fly ash than mixtures with Portland cement
only.
Uses of fly ash CONCRTE
Mass concrete section
Ready mix and precast application.
Marine environment concretes
For use with alkali-reactive aggregates
Water retaining structure
Self compacting concrete
Tunnelling concretes
Road stabilization
Pumped concrete
EXPERIMENTAL PROGRAMS
Experiment work is carried out to study mechanical
properties of normal concrete and concrete with Fly Ash
like compressive strength and workability of concrete. Fly
Ash are used for study purpose by varying percentage of
fly ash as 5%, 10%, 15%, 30 and 45 % of weight of
cement.
FLY CONCRE TEST
1. Slump test.
2. Compression test.
Slum Test To determine the workability of concrete mixes of given
proportion by SLUMP TEST.
Prepare four concrete mixes with varying water cement
ratio say 0.50.Use 2.5 Kg of cement,5 Kg of fine
aggregate and 10 Kg of coarse aggregate for each
mix(1:1.5:3 ratio).The ingredients be first mixed dry
thoroughly before adding water.
Fill the freshly mixed concrete in a clean slump cone in 4
successive layers, tamping each layer properly (25 times)
before adding another.
Slum Test
Compressive Test To determine the compressive strength of fly ash concrete
(concrete M20)
The determination of compressive strength of concrete is
very important because the compressive strength is
criterion of its quality.
The strength is expressed in N/mm2.
The concrete specimens are generally tested at ages of 7
days, 14 days and 28 days
Compressive Test
compressive strength Testing
compressive strength observation table for 28 day
% OF FLY ASH COMPRESSION % DIFFERENT
STRENGTH W.R.T. NORMAL
CONCRETE
0 23.28 0
5 26.96 9.24
10 28.40 15.07
15 20.30 -17.75
30 12.20 50.57
45 9.44. 61.75
CONCLUSIONWorkability in terms of slump value
Decease with increase in % replacement of fly ash
At 5% replacement concrete is having medium
workability
At 10% replacement concrete is having low workability
At 15% replacement concrete is having very low
workability
CONCLUSION Cube compression test
Decease with increase in % replacement of fly ash
9.24% increase at 5% replacement at 28 days
15.07% increase at 10% replacement at 28 days
So, from the observed test results, replacement of cement
by fly ash in concrete is practically possible up to 10%
only. If 15% or more replacement is required, plasticizers
should be used to have required workability.
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