1

A MNI-PROJECT REPORT

ON

PREPARING & TESTING OF FLY ASH SOIL BLOCKS

A Mini-Project Report submitted in partial fulfillment of the

Requirement for the award of degree of

Bachelor of Technology

In

Civil Engineering

By

R. KRISHNA REDDY (08091A0121)

M. JOSHNA RANI (08091A0114)

S. RAMUKUMAR (09095A0104)

M.RAJU (08091A0140)

M. PULLA REDDY (08091A0137)

UNDER THE ESTEEMED GUIDENCE OF

Mr. C. KRISHNAMA RAJU, M.E.

Associate Professor

Department of Civil Engineering

R.G.M College of Engineering & Technology, Nandyal-5180501

(Affiliated to J.N.T UNIVERSITY, ANANTAPUR, A.P INDIA)

(Approved by AICTE, Accredited by N.B.A New Delhi)

(Participated in World Bank Aided TEQIP-I)

YEAR (2008-2012)

2

R.G.M College of Engineering & Technology, Nandyal-5180501

(Affiliated to J.N.T UNIVERSITY, ANANTAPUR, A.P INDIA)

(Approved by AICTE, Accredited by N.B.A New Delhi)

(Participated in World Bank Aided TEQIP-I)

DEPARTMENT OF CIVIL ENGINEERING

CERTIFICATE

This is to Certify that the Mini-Project entitled “PREPARING &

TESTING OF FLY ASH SOIL BLOCKS” that is being submitted by

R.KRISHNA REDDY (08091A0121), M.JOSHNA RANI (08091A0114),

S. RAMUKUMAR (09095A0104), M.RAJU (08091A0140) and M.PULLA

REDDY (08091A0137) in partial fulfillment for the award of degree of

Bachelor of Technology In Civil engineering to the Rajeev Gandhi

Memorial College of Engineering & Technology, Nandyal (Affiliated to

J.N.T UNIVERSITY, ANANTAPUR.) is a record of bonafide work carried

out by them under our guidance and supervision. The results

embodied in this Mini-Project have not been submitted to any other

University or Institute for the award of any degree.

GUIDE Head of the Department

Mr. C. KRISHNAMA RAJU Mr. C. KRISHNAMA RAJU

Associate Professor Associate Professor

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Acknowledgement

We express our deep sense of gratitude and honor to our Mini-

Project guide and HOD Sri C. Krishnama Raju M.E., Associate

Professor for his encouragement and inspired guidance throughout

the Mini-Project work for successful completion.

We are also highly grateful to our Principal Dr. T. Jayachandra

Prasad, Ph.D. for his kind help, inspiration & encouragement in

completing the Mini-Project work.

We would like to thank our Chairman Dr. M.

Santhiramudu, and our M.D. Sri M. Sivaram, for encouragement

and providing various facilities in completing the Mini-Project work.

R. KRISHNA REDDY (08091A0121)

M. JOSHNA RANI (08091A0114)

S. RAMUKUMAR (09095A0104)

M.RAJU (08091A0140)

M. PULLA REDDY (08091A0137)

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CONTENTS

CHAPTER1: INTROUCTION

CHAPTER2: PROPERTIES OF SOME BUILDING MATERIALS

2.1: Properties of fly ash

2.2: Properties of clay 2.3: Properties of silica 2.4: Properties of lime

2.5: Properties of Ordinary Portland cement

CHAPTER3: TYPE OF BRICKS 3.1: Common Burnt Clay Bricks 3.2: Sand Lime Bricks (Calcium Silicate Bricks)

3.3: Concrete Bricks 3.4: Fire Clay Bricks

3.5: Fly ash soil bricks

CHAPTER 4: PREPARATION OF FLY ASH BLOCKS

4.1: Preparation of mould 4.2: Procurement & Testing of Raw Material

4.3: Different Proportions of raw materials 4.4: Preparation of blocks

CHAPTER 5: RESULTS

CHAPTER 6: COMPARISION OF RESULTS

CHAPTER 7: CONCLUSION

CHAPTER 8: SCOPE OF FEATURE WORK

CHAPTER 9: REFERENCES

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TABLE N0: Page No.

1.1……………………………………………………………..8

1.2……………………………………………………………..8

2.1…………………………………………………………….12

2.2…………………………………………………………….12

2.3…………………………………………………………….13

2.4…………………………………………………………….21

2.5…………………………………………………………….21

3.1…………………………………………………………….28

4.1…………………………………………………………….29

4.2…………………………………………………………….29

4.3…………………………………………………………….30

5.1…………………………………………………………….34

5.2…………………………………………………………….35

5.3………………………………………………………….…36

6.1………………………………………………………….…38

FIGURES NO:

3.1……………………………………………………………24

3.2…………………………………………………………....26

3.3…………………………………………………………….27

4.1…………………………………………………………….31

4.2………………………………………………………….…31

4.3………………………………………………………….…32

4.4…………………………………………………………….32

4.5………………………………………………………….…32

4.6………………………………………………………….…32

4.7………………………………………………………….…32

5.1………………………………………………………….…33

5.2………………………………………………………….…33

6

GRAPHS NO:

4.1…………………………………………………………….30

5.1…………………………………………………………….34

5.2…………………………………………………………….35

5.3…………………………………………………………….36

5. 4……………………………………………………………37

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ABSTRACT

The demand for buildings (utilized for living, offices etc) is

increasing day by day with increasing population and needs of the

people. Due to this the demand for bricks also increases. Steel,

cement, glass, aluminum, plastics, bricks, etc. are energy intensive

materials. For sustainable development energy efficient and eco-

friendly materials are needed.

In the present mini-project titled “Preparation & Testing of Fly

ash soil Blocks” the Fly ash soil Blocks using soil, fly-ash, sand,

quarry dust and lime in different proportions are prepared, tested &

results are reported. For all the proportions the 28 day compressive

strength is more than 2.5 MPa. These blocks are energy efficient and

eco-friendly because blocks are water cured and fly ash is industrial

waste.

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1. INTRODUCTION:

The demand for buildings (utilized for living, offices etc) is

increasing day by day with increasing population and needs of the

people. Due to this the demand for bricks also increases. Projected

demand for building materials like bricks, steel and cement consumed

in bulk quantities is given in table 1.1. (Ref.1).

Table 1.1: Projected demand for building materials

Material 2000 2020

Bricks(No’s) 150x109 246x109

Structural steel

(tonnes)

11x106 30x106

Cement (tonnes) 96x106 255x106

Steel, cement, glass, aluminum, plastics, bricks, etc. are energy

intensive materials, commonly used for building construction.

Generally these materials are transported over great distances. Energy

(fossil fuel energy) spent in transportation of some of these building

materials using trucks is given in table 1.2. (Ref. 1).

Table 1.2: Energy in transportation of Building materials

Building materials Unit Energy in transportation for

100km(MJ)

Bricks m3 200

Sand m3 175

Cement Tonne 100

Steel Tonne 100

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Extensive use of these materials can drain the energy resources

and adversely affect the environment. On other hand, it is difficult to

meet the ever growing demand for buildings by adopting only energy

efficient traditional materials (like mud, thatch, timber etc.) and

construction methods. Hence, there is a need optimum utilization of

available energy resources and raw materials to produce simple,

energy efficient, environment friendly and sustainable building

alternatives and techniques to satisfy the increasing demand for

buildings.

Some of the guiding principles in developing the sustainable

alternative building technologies can be summarized as follows:

Energy conservation; Minimize the use of high energy materials;

Concern for environment, environment friendly technologies; Minimize

transportation and maximize the use of local materials and

resources; Decentralized production and maximum use of local skills;

Utilization of industrial and mine wastes for the production of building

materials; Recycling of building wastes, and use of Renewable energy

sources.

Building technologies manufactured by meeting these principles

could become sustainable and facilitate sharing the resources

especially energy resources more efficiently, causing minimum

damage to the environment.

In the light of the above, the present mini-project titled

“Preparation & Testing of Fly ash Soil Blocks” is considered. The Fly

ash Soil Blocks are prepared using soil, fly-ash, sand, quarry dust

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and lime in different proportions, tested & results are reported. These

blocks are energy efficient and eco-friendly because blocks are water

curried and fly ash is industrial waste.

The present work is organized into different chapters.

Chapter 2 discusses about properties of some building

materials.

Chapter 3 discusses about different types of bricks.

Chapter 4 discusses about Preparation of Fly ash Soil Blocks.

Chapter 5 discusses Results.

Chapter 6 compares the results with brick other blocks.

Chapter 7 presents conclusions.

Finally scope of future work & references are reported.

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2: PROPERTIES OF SOME BUILDING MATERIALS

2.1: Properties of fly ash:

The quality of fly ash is governed by IS 3812-part 1-2003. The BIS

specification limit for chemical requirement are given in table 2.1 and

2.2 (IS 3812-2003). High fineness, low carbon content and good

reactivity is the essence of good fly ash. Since fly ash is produced by

rapid cooling and solidification of molten ash, large portion

component comprising fly ash particles are in amorphous state. The

amorphous characteristics greatly contribute to the puzzolana

reaction between cement and fly ash. One of the important

characteristics of fly ash is the spherical form of the practices. This

shape of particle improves the flow ability and reduces the water

demand. The stability of fly ash could be decided by finding the

density of fully compacted sample.

ASTM broadly classifies fly ash into two classes.

Class F: Fly ash normally produced by burning anthracite or

bituminous coal. Usually has less than 5% coal class F fly ash has

Puzzolana properties.

Class C: Fly ash normally produced by burning lignite or sub-

bituminous. Some class C fly ash may have CaO content in excess of

10% in addition to puzzolana properties. Class C fly ash also

possesses cementations properties.

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Table 2.1: Chemical requirement (Ref.2)

Sl.no (1)

Characteristic (2)

Requirement (3)

(1)

(2) (3)

(4) (5)

(6)

(7) (8)

Silicon dioxide (SiO3) plus aluminum oxide (Al2O3)plus iron oxide (FeO) percent by mass,

Min Silicon dioxide (SiO3) percent by mass, Min Reactive silica in percent by mass, Min

Magnesium oxide (MgO) percent by mass, Max Total sulphur as sulphur trioxide(SO3) percent by mass, Max

Available alkalis, as sodium oxide (Na2O)percent by mass, Max

Total chloride in present by mass, Max Loss on ignition, percent by mass, Max

70.0

35.0 20.0

5.0 3.0

1.5

0.05 5.0

Limits regarding moisture content or fly ash shall be as agreed to

between the purchaser and the supplier. All tests for properties

specified shall, however, are carried out on over dry samples.

Table 2.2: Physical requirements (Ref.2)

Sl. No (1)

Characteristic (2)

requirement grade of fly ash І ІІ

(3) (4)

(1) (2)

(3)

(4)

Fineness specific surface in m2/kg by Blaine s permeability method. Min Lime reactive –average compressive

strengths in n/mm2, min Compressive strength at 28 days

n/mm2 , min

Soundness by autoclave test

expansion of specimens, percent, max.

320 250 4.5 3.0

Not less than 80

percent of the strength of the corresponding plain

cement cubes 0.8 0.8

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Fly ash, when tested in accordance with the methods of test

specified in IS: 1727-1967, shall conform to the chemical

requirements give in table 2.3.

Table 2.3: Illustrative properties of fly ash from different sources (Ref.3)

Property/ source A B C D E

Specific gravity 1.91 2.12 2.10 2.25 2.146 to 2.429

Wet sieve analysis

(percentage retained on no 325 BS sieve)

16.07

54.65

15 60

5.00

51.00(dry)

Specific surface (cm2/g balance)

2759 1325 2175 4016 2800to3250

Lime reactivity (kg/sq.cm)

Chemical analysis

86.8

56

40.03

79.3

56.25 70.31

Loss on ignition percentage 5.02 11.33 1.54 7.90 1-2

Si02 50.41 50.03 63.75 60.10 45-59

S03 1.71` - - - 45-59

P208 0.31 - - - Trace to 2.5

Fe203 3.34 10.20 30.92 6.40 0.6-4

Al303 0.66 18.20 - 18.64 23.33

Ti2 0.84 - - - 0.5-1.5

Mn2O3 0.31 - - - -

CaO 3.04 6.43 2.35 6.3 5-16

MgO 0.93 3.20 0.95 3.6 1.5-5

Glass content: highly variable within and between the samples but generally below 35%

Nearly 110 million tones of fly ash are generated in 2010 in

India from thermal power plants set up at various places. Processes

have been developed for production of clay fly ash bricks and bricks

using fly ash and sand with addition of lime or chemical with or

without autoclaving

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2.2: Properties of Clay:

There are two types of clays that are recognized, the silicate clays of

temperate regions and the iron and aluminum hydroxide clays found

in the tropics and semi tropics. The great agricultural regions of the

world are dominated in a large degree by clays of a siliceous nature.

All clay particles are crystalline and not amorphous as was originally

supposed.

Each clay particle regardless of its individual shape is made up of

sheet like molecules or units, held loosely together. Clay particles will

also show considerable variation in size. These units are quite definite,

usually changing in size only by lateral extension. A clay particle

might be visualized by comparing it with a piece of mica as the flakes

of the latter represent the plate like molecules or units.

Clay particles because of their fineness of division must expose a

large amount of external surface. There are also internal surfaces as

well, the sum of which usually greatly exceeds that of a superficial

character.

It has been shown that clay particles are composed of two distinct

parts, the inner, porous, and enormously larger insoluble acidosis, or

micelle, and the outer and more or less dissociated swarm of cat ions

with variable amounts of water of hydration. Since these absorbed cat

ions are usually rather easily displaced, they are spoken of as

exchangeable ions. This replacement, called ionic exchange, or more

15

commonly Base Exchange, is one of the most important of all soil

phenomena.

Calcium and magnesium are the absorbed metallic cat ions held in

the largest amounts by the siliceous clays of most natural soils. Since

so much of the total calcium is replaceable, its activity is assured. The

main concern, therefore, is the amount present thus we use the

practice of liming. With potash the total amount is often ample, but

the proportion active is exceedingly small.

Two groups of clay are commonly recognized, the kaolin and the

montmorillonite. The molecules of the kaolin are thought to be

composed of two sheets or plates, one of silica and one of alumina.

The second group, the montmorillonite, is composed molecularly of

two silica sheets and one of alumina. The molecules of these clays are

less firmly linked together than those of the kaolin group and are

usually further apart.

In discussing the mineralogical nature of silicate clay, it must not

be forgotten that other minerals besides the ones mentioned are

present, either as mere accessories or as an important part of the

colloidal complex. Of these, the hydrated oxides of silicon, iron, and

aluminum should be mentioned. While these probably occur but

sparingly in temperate-region soils, the latter two are especially

important in tropical and semitropical regions, giving rise to what are

spoken of as late rite soils. The silicate clays often contain a larger

16

and larger admixture of colloidal iron and aluminum oxides. The red

and yellow soils of our southern states are very good evidence of this

transition.

2.3: Properties of silica:

SILICA is the most abundant mineral found in the crust of the

earth. It forms an important constituent of practically all rock-forming

minerals. It is found in a variety of forms, as quartz crystals, massive

forming hills, quartz sand (silica sand), sandstone, quartzite, Tripoli,

diatomite, flint, opal, chalcedonic forms like agate etc., and in with

numerous other forms depending upon color such as purple quartz

(amethyst), smoky quartz, yellow quartz or false topaz (citrine), rose

quartz and milky quartz. Only pure quartz crystal or rock crystal,

untwined, clear, free from any inclusion, has an important property.

It expands (mechanically) under the influence of electric current

and conversely pressure induces a measurable electric current. This

property is known as piezoelectricity. The current thus developed is

called piezoelectric current.

This property resulting from the asymmetry of its atomic groups

makes quartz an effective transducer for converting electrical energy

into mechanical energy and vice-versa. This property in quartz

crystals was discovered in 1880-82 by Pierre and Jacques Curie and

remained a laboratory curiosity till in 1921 when W.G. Cady, a

physicist, discovered that quartz plates could be used to control the

frequency of wireless transmission circuits.

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This discovery marked the dawn of quartz crystal application in

modern communication equipments. A very thin plate of quartz is so

cut that the frequency of the oscillating circuit corresponds with the

quartz plate and when such plate is inserted in a radio receiving set or

radio transmitter it prevents frequencies from wandering and

deviation and greatly reduces interference.

Quartz plate is used in controlling frequencies in air and water

media as well. It is largely used in radio circuit, radar, ultrasonic and

in multiple telephone lines. Quartz plates keep the broadcast on the

right beam.

Quartz crystals cut into prisms, wedges and lenses are used for

microscopes and other optical instruments. Quartz wedge is the

commonest accessory which students use in the petro logical

microscope.

A number of other crystals giving piezoelectricity are known but

none compares with quartz. Chemically prepared Rochelle salt and

Barium titan ate have been found good substitutes for piezoelectric

quartz.

However, the crystal - quartz because of its chemical and physical

stability and high elasticity has remained indispensable so far. The

consumption of quartz plate pieces has tremendously increased with

the increase in the manufacture of modern receiving sets.

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2.4: Properties of lime:

Lime:

Lime is a generic term, but by strict definition it only embraces

manufactured forms of lime – quicklime (CaO) and hydrated lime (Ca

(OH)2). It is, however, sometimes used to describe limestone products

which might be a cause of confusion.

The raw material for all lime-based products is a natural stone:

limestone, which is composed almost exclusively of calcium carbonate

(CaCO3). When limestone contains a certain proportion of magnesium,

it is called dolomite, or dolomites’ limestone (CaMg (CO3)2). It is widely

geographically available all over the world (the Earth’s crust contains

more than 4% calcium carbonate) and also widely used for many

different purposes. In the lime or dolomite production processes, the

blocks of limestone or dolomite obtained after blasting in the quarry

are crushed and sorted by size in screening plants. At this stage:

Part is used directly, for example as aggregates for road

construction, for concrete or other applications.

Part is ground to lime fertilizer or pulverized into limestone

powder, used in applications such as flue, Gas-cleaning, animal

feed or as fillers in many products (concrete, asphalt, carpet-

backing…).

The rest, high quality limestone with a defined particle size is

calcinated in a lime burning plant at a temperature of 900-1200°C, at

which temperature it is decarbonated in either vertical or rotary kilns

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fired with gas, oil, coal, coke or other fuels. During that process,

carbonate is converted into oxide (Cao or CaMgO) and CO2 is released.

The combustion phase is essential for obtaining a quality lime that

satisfies the required characteristics. First it is important to adjust

reactivity because the various applications require reaction times

(reaction of oxide with water) that can vary from a few seconds to more

than thirty minutes. In addition the products must possess precise

physical and chemical characteristics because of different standards

for certain applications. The quicklime obtained can be used as such,

or can be crushed, finely ground, or micronized depending on its

intended use. Quicklime can also be hydrated, i.e. combined with

water in a hydrator. The quantity of water added is about twice the

stoichiometric amount required for the hydration reaction. The excess

water is added to moderate the temperature generated by the heat of

reaction by conversion to steam. The end product is hydrated lime or

slaked lime (Ca (OH)2) in the form of a very fine powder suitable for a

variety of applications. Milk of lime and lime putty is produced by

slaking of lime with excess water. Slaking is done in both batch and

continuous slackers. The term milk of lime is used to describe a fluid

suspension of slaked lime in water. Milks of lime may contain up to

40% by weight of solids. Milk of lime with high solids content is

sometimes called lime slurry. Lime putty is a thick dispersion of 55 to

70% by weight of slaked lime in water. Lime paste is sometimes used

to describe semi-fluid putty.

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Multiple properties – manifold uses

Lime can be used for a wide range of purposes because of its

different characteristics:

Alkaline reaction of lime with water (neutralization,

coagulation, flocculation)

Forming of water insoluble calcium salts (precipitation of

heavy metals and sulphates)

Re-carbonation reaction with CO2 (hardening of plaster,

increase of acid capacity)

Pozzolanic reaction with silicates (forming of calcium

silicates)

Heat generation by contact of quicklime with water (drying,

pasteurization, disinfection)

While lime is one of the earliest industrial commodities known to

man, its production and uses have grown with the times, and it

continues to be one of the essential building blocks of modern

industry.

Properties of Ordinary Portland cement (OPC):

It is the most type of cement. Prior to 1987, there was only one

grade of OPC which was governed by IS 269-1976. After 1987 higher

grade cements were introduced in India. The OPC was classified in to

3 grades, namely 33 grade, 43 grade and 53 grade depending upon

the strength of cement at 28 days when tested as per IS 4031-1988. If

the 28 days strength is not less than 33Mpa, it is called 33grade

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cement, if the strength is not less than 43Mpa, it is called 43grade

cement and if the strength is not less than 53Mpa, it is called 53grade

cement. But the actual strength obtained by these cements at the

factory is much higher than the BIS specifications.

The physical and chemical properties of 33, 43 and 53 grade OPC

are shown in table

Table2.4: Physical properties (Ref.4)

Sl.

no

Type of

cement

(OPC)

Fineness Soundness by Setting time

(mts)

Compressive

strength (min. Mpa)

(m2/kg)Min.

Le chatelier

(mm) max.

Auto clave

(%) Max.

Initial min

Final

max.

3 days

7 days

28 days

1 33 grade 225 10 0.8 30 600 16 22 33

2 43 grade 225 10 0.8 30 600 23 33 43

3 53 grade 225 10 0.8 30 600 27 37 53

Table2.5: Chemical properties (Ref.4)

Sl.

no

Type of

cement

Lime

saturation factor (%)

Alumi

na iron Ratio

(%) Min.

Insolu

ble Residue (%)

Max.

Magne

sia (%) Max.

Sulphuric

Anhydride

Loss of

magnesia (%) Max.

1 33 grade

0.66 min.

1.02max.

0.66 4 6 2.5% max. When

C3A is 5 or less 3%

max. when C3A > 5

5

2 43

grade

0.66 min.

1.02max

0.66 2 6 2.5% max. When

C3A is 5 or less 3%

max. when C3A > 5

5

3 53 grade

0.8 min

1.02max.

0.66 2 6 2.5% max. When

C3A is 5 or less 3%

max. when C3A > 5

4

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3. TYPE OF BRICKS

There are various type of bricks used in masonry.

1. Common Burnt Clay Bricks

2. Sand Lime Bricks (Calcium Silicate Bricks)

3. Concrete Bricks

4. Fire Clay Bricks

5. Flay ash soil bricks

3.1: Common Burnt Clay Bricks

Clay bricks are fired bricks. These are formed by pressing in

moulds or by an extrusion and wire cutting process. Then these

bricks are dried and fired in a kiln.

3.2: Sand lime bricks

In the early 'eighties of the 19th century, Dr Michaels of Berlin

patented a new process for hardening blocks made of a mixture of

sand and lime by treating them with high-pressure steam for a few

hours, and the so-called sand-lime bricks are now made on a very

extensive scale in many countries. There are many differences of detail

in the manufacture, but the general method is in all cases the same.

Dry sand is intimately mixed with about one-tenth of its weight of

powdered slaked lime; the mixture is then slightly moistened with

water and afterwards moulded into bricks under powerful presses,

capable of exerting a pressure of about 60 tons per sq. in. After

removal from the press the bricks are immediately placed in huge

steel cylinders usually 60 to 80 ft. long and about 7 ft. in diameter,

and are there subjected to the action of high-pressure steam (120 lb to

23

150 lb per sq. in.) for from ten to fifteen hours. The proportion of

slaked lime to sand varies according to the nature of the lime and the

purity and character of the sand, one of lime to ten of sand being a

fair average.

The following is an analysis of a typical German sand-lime brick:

silica (SiO), 84%; lime (Cao), 7%; alumina and oxide of iron, 2%;

water, magnesia and alkalis, 7%. Under the action of the high-

pressure steam the lime attacks the particles of sand, and a chemical

compound of water, lime and silica is produced which forms a strong

bond between the larger particles of sand. This bond of hydrated

calcium silicate is evidently different from, and of better type than, the

filling of calcium carbonate produced in the mortar-brick, and the

sand-lime brick is consequently much stronger than the ordinary

mortar-brick, however the latter may be made. The sand-lime brick is

simple in manufacture, and with reasonable care is of constant

quality. It is usually of a light-grey color, but may be stained by the

addition of suitable coloring oxides or pigments unaffected by lime

and the conditions of manufacture. Fig 3.1 shows the sand lime

bricks.

24

Fig: 3.1sand lime bicks

3.3: Concrete bricks

Concrete brick is made from solid concrete. These bricks are used

to cover the facade of a home, build fences, and enhance the overall

beauty of a home's exterior. Bricks that are made from concrete come

in a number of styles and colors making them extremely popular

amongst homeowners. Concrete bricks also have many other

appealing attributes.

While regular brick does a fine job of insulating a home, concrete

brick tends to be a better insulation option. Traffic, airplanes, and

other outside noises are effectively muted, thanks to the solid concrete

that these bricks are made from. Other benefits of concrete brick

include better fire protection, less exterior home maintenance, and

lower energy bills. Bricks that are fashioned from concrete are

available in a number of different styles. Consumers can select from a

smooth, rough, textured, glossy, sandblasted, or stone finish. Various

manufacturers may also offer customized bricks according to a

consumer's specifications. In addition, hundreds of different color

25

options are available -- most manufacturers will customize bricks to

meet a homeowner's needs.

Concrete bricks are quickly becoming a popular alternative to

other home facade materials. While the cost of installing this type of

brick may be higher than the cost of installing other materials,

concrete brick will last a lot longer than most other substances. In

fact, concrete brick tends to mature with age creating a desired

timeless look.

While durable and attractive, these bricks are not indestructible.

Bricks made from concrete will generally last up to twelve years. After

this length of time has passed, small bits of brick may begin to break

off of each piece. At this point, certain bricks will have to be replaced,

though this can be done on an individual brick basis.

There are many positive aspects of these bricks, but there are also

some negative aspects. Concrete may shrink once it has been

installed. This often results in gaps between bricks, which can allow

outside water to seep into a home. Also, there is no way to prevent

color from leaking out of concrete, which may result in faded bricks.

Concrete brick is a very effective way to make a strong first

impression. When people walk up or drive by a home with concrete

brick, second glances are common reactions. If you own a home with

concrete brick as your exterior veneer, you already know this. If you

are planning on using it, be prepared to have your neighbors ask

26

questions while admiring the beauty of your concrete brick.

Concrete brick has more benefits than its striking visual qualities.

They deaden exterior noise, giving you and your family a buffer from

traffic noise, airplanes flying overhead and other various disruptions.

Fire protection is another benefit of concrete brick. Giving your family,

and the fire department, extra time is never a bad thing. You won't

have to worry about maintenance with concrete bricks finally;

concrete brick walls can improve the thermal mass qualities of your

exterior walls, thus improving your energy bills. Fig: 3.2shows the

Concrete brick.

Fig: 3.2 concrete bricks

3.4: Fire clay bricks

Fire clay exists at much depth below the surface and is usually

mined. Generally, Fire clays contain metallic oxides less than surface

clays and have more uniform chemical and physical properties.

Fire clay bricks are produced from Fire clay is used for

manufacturing of all sorts of refractory materials and due to its

alumina and silica content, it leads to the formation of highly heat

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resistant fireclay bricks. Normally, fireclay is clay that has higher

content of Alumina. Normally, alumina content in fire clay is 24 or

34% while the silica content is 50 or 60%.

Fire clay bricks are used for building construction including fire

place construction and huge industrial furnace construction. These

products are used in the core industries such as Steel Industry,

Aluminum Industry, Cement Industry, Ceramic Industry,

Electroplating Industry, Chemicals Plants, Dairy Plants, Fertilizers

Plants and Forging Plants. The fireclay bricks are highly useful in the

boiler and sugar industry, boiler cupola and steel foundry, cement

pre-heater cyclone, silicate furnace, boilers incinerators, cement kiln,

preheating zone and preheating furnace wall.

Fig: 3.3 fire clay bricks

3.5: Fly ash Soil Bricks

Fly Ash soil bricks are made of fly ash, lime, soil and sand. These

can be extensively used in all building constructional activities.

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Fly ash is used as main raw material to prepare fly ash soil blocks

because, it is being accumulated as waste material in large quantity

near thermal power plants and creating serious environmental

pollution problems, its utilization as main raw material in the

manufacture of bricks will not only useful in disposal but also help in

environmental pollution control to a greater extent in the surrounding

areas of power plants.

Also there is ever increasing demand for power generation in the

country. In our country major power is generated from thermal power

plants which are coal based and they generate fly ash as waste

product. The Table3.1 (Ref.5) shows the thermal power generation,

coal consumption and ash generation in India.

Table 3.1: Thermal power generation, coal consumption and ash

generation in India (Ref.5)

Year Thermal power generation (MW)

Coal consumption (MT)

Ash generation (MT)

1995 54,000 200 75

2000 70,000 250 90

2010 98,000 300 110

2020 137,000 350 140

The preparation and results of these blocks are discussed in next chapters.

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4. PREPARATION OF FLY ASH SOIL BLOCKS:

4.1 Preparation of mould

The mould is prepared with fly wood flanks having inner

dimensions of 305x143x100 mm.

4.2 Procurement & Testing of Raw Material

Fly ash from T.G Venkatesh power plant, Kurnool; soil from

Shanthi Ram Engineering College, Nandyal; Quartz dust from stone

quarry near Orvakallu, Lime from Nandyal are collected.

The specific gravity of soil, sand and quartz dust is determined by

using pychnometer and particle size distribution for fly ash, soil,

sand, quartz dust is determined by using dry sieve analysis method.

The results are shown in table 4.1, 4.2 and particle size distribution

curves in Graph 4.1.

Table 4.1: Specific Gravity

SNo Material Specific Gravity

1 Soil 2.38

2 Sand 2.56

3 Quartz dust 2.00

Table 4.2: Sieve Analysis

SNo Material % Gravel % Sand % Silt & Clay

1 Soil 10.37 88.73 0.90

2 Sand 0 99.66 0.34

3 Quartz dust 0 93.00 7.00

4 Fly Ash 0 96.20 3.80

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Graph 4.1 patrical size distribution curves

4.3 Different Proportions of raw materials:

Five different proportions of raw materials are considered for

making the Fly ash Soil Blocks as shown in table 4.3. For first four

proportions 4 blocks are prepared and for fifth proportion 2 blocks are

prepared.

Table 4.3: Different Proportions

Sl. No Fly ash (%) Soil (%) Sand (%) Quartz dust (%) Lime (%) Water (%)

1 20 60 7 7 6 41

2 30 50 7 7 6 42.5

3 40 40 7 7 6 44

4 50 30 7 7 6 45

5 60 20 7 7 6 46

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4.4 Preparing of block:

The proportion of the raw materials (i.e. Fly ash, lime, sand, Soil

and quartz dust) are taken according to the table 4.3 into the pan and

mixed thoroughly. Then water is added about 40- 45% to get

workability and it becomes paste.

The paste is poured as 3 layers in to the mould, each layer is

tamped with tamping rod to avoid voids and this mould is shifted to

the C.B.R (California bearing ratio) for applying load up to 200 Kg on

the block. After loading, the block is removed carefully from the mould

then it is kept in open air up to 24 hours for drying and the block is

cured in presence of water for required days.

The step by step procedure for preparation of blocks as shown

figures: 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7.

Fig: 4.1 Mixing of raw mateials Fig: 4.2 Block paste

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Fig 4.3: Pouring paste in to the mould Fig4.4: C.B.R (for loading)

Fig: 4.5: Block with mould Fig 4.6: Removing the mould

Fig4.7: Fly ash soil blocks

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5. RESULTS:

The cured blocks are removed from the water and dried to open

air then the bricks are weighted, dimensions are noted to find

density of the blocks and these blocks are tested by using Universal

testing machine (U.T.M) to find the compressive strength of the fly

ash soil blocks.

Fig5.1: U.T.M machine Fig 5.2: Testing the block

The test results of blocks are shown in graphs 5.1, 5.2 & 5.3 for

3, 14, 28 days, and also maximum load and compressive strengths

for various proportions of blocks are shown in tables: 5.1, 5.2, and

5.3.

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Table 5.1 FOR 3 DAYS

Bricks with different proportions

Maximum load (KN) Compressive strength (N/mm^2)

FSB1.1 21.87 0.5

FSB1.2 24.15 0.56

FSB2.1 27.6 0.64

FSB2.2 25.11 0.58

FSB3.1 27.03 0.6

FSB3.2 23.58 0.55

FSB4.1 23.95 0.56

FSB4.2 22.9 0.54

Graph 5.1: Compressive strength for 3 days

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Table 5.2 FOR 14 DAYS

Bricks with different

proportions

Maximum load (KN) Compressive

strength (N/mm^2)

FSB1.3 73.95 1.73

FSB1.4 70.05 1.64

FSB2.3 91.68 2.16

FSB2.4 87.8 2.06

FSB3.3 83.73 1.94

FSB4.3 110.97 2.60

FSB5.1 112.38 2.64

Graph 5.2 Compressive Strength for 14 days

36

Table 5.3 FOR 28 DAYS

Bricks with different

proportions

Maximum load (KN) Compressive

strength (N/mm^2)

FSB3.4 114.7 2.67

FSB4.4 112.63 2.63

FSB5.2 119.28 2.78

Graph 5.3 Compressive Strength for 28 days

37

Graph 5.4 shows the variation of compressive strength for different

proportions for 3, 14, 28 days.

Graph5. 4 Variation of Compressive Strength

The following points are drawn from the above results.

For 3 days the compression strength of fly ash soil blocks is 0.5

to 0.6Mpa.

For 14 days the compression strength of fly ash soil blocks is

>1.7Mpa.

For 28 days the compression strength of fly ash soil blocks is >

2.5Mpa.

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6. COMPARISION OF RESULTS

Table 6.1: Compressive Strengths of various bricks

Sl. No Type of bricks Compressive strength

1 Common burnt clay bricks (Ref.6)

I. Class

II. Class

III. Class

Not less than 10.5Mpa.

Not less than 7.5Mpa.

>3.5Mpa.

2 Stabilized mud Bricks (Ref.1) 3- 4Mpa.

3 Fine concrete blocks (Ref.1) >3Mpa.

4 Fly ash soil blocks >2.5Mpa.

The Fly ash soil blocks have got less compressive strength

compared to bricks, stabilized mud bricks & Fine concrete blocks.

Hence these blocks can be used for partition walls, parapet wall &

temporary structures.

39

7. CONCLUSION

The maximum compressive strength is 2.78 MPa for 5th

proportion (i.e. fly ash 60%, soil 20%, sand7%, quartz dust7%

and lime6%).

The increase in compressive strength from 3 to 14 days is about

1.1Mpa and from 14 to 28 days is about 0.8 Mpa.

As the fly ash content is increased the compressive strength of

fly ash soil blocks is also increases.

Emphasizes the need for using alternative materials for

protecting the Environment and for sustainable development.

40

8. SCOPE OF FUTURE WORK

1. The work can be extended by using cement in place of lime.

2. The work can be extended by increasing lime percentage.

3. The work can be extended by increasing the compressive

load during moulding of block.

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9. REFERENCES

1. Sustainable Building Technologies by B.V. Venkatarama Reddy,

IISc, Bangalore; CURRENT SCIENCE, VOL.87, NO 7, 10 OCTOBER

2004.

2. IS: 3812-part-1-2003.

3. IS: 1727-1967.

4. CONCRETE TECHNOLOGY BY M.S SHETTY.

5. CURRENT SCIENCE, VOL. 100, NO. 12, 25 JUNE 2011 IS 269-

1989

6. BUILDING MATEIALS BY S.K DHUGGAL

-

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