1

STUDY OF REPLACEMENT OF NATURAL SAND

WITH MANUFACTURED SAND IN CONCRETE

Project report

Submitted in partial fulfillment of the requirements for the award of the Degree

BACHELOR OF TECHNOLOGY

IN

CIVIL ENGINEERING

BY

L.SATISH KUMAR (Y9CE862)

L.ANJANEYULU (Y9CE863) M.MANOJ KUMAR (Y9CE864)

P.VIJAYARAMA RAJU (Y9CE882) N.SUMAN KANTH (Y9CE881)

Under the esteemed guidance of

Dr. M.RAMA RAO, M.E., PhD

Professor of Civil Engineering

DEPARTMENT OF CIVIL ENGINEERING

R.V.R & J.C. COLLEGE OF ENGINEERING

(Autonomous)

(Approved by A.I.C.T.E & Affiliated to ACHARYA NAGARJUNA UNIVERSITY),

Chowdavaram,Guntur-522019, Andhra Pradesh, 2009-2013

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CERTIFICATE

This is to certify that this project report entitled STUDY OF OF REPLACEMENT OF

NATURAL SAND WITH MANUFACTURED SAND IN CONCRETE Is bonafied record

of work done by L.SATISH KUMAR (Y9CE862) , L.ANJANEYULU (Y9CE863)

,M.MANOJ KUMAR (Y9CE864) , P.VIJAYARAMA RAJU (Y9CE882) , N.SUMAN KANTH

(Y9CE881) under my guidance and supervision and submitted in partial fulfillment of the

requirements for the award of the degree of BACHELOR OF TECHNOLOGY in CIVIL

Engineering by Acharya Nagarjuna University, during the year 2009-2013.

GUIDE H.O.D of Civil Engineering

Dr. M.RAMA RAO,M.E.,Ph.D Dr. K.SAIRAM, M.TECH, PhD

Professor of Civil Engineering R.V.R&J.C College of Engineering

R.V.R&J.C college of Engineering Chowdavaram

Chowdavaram Guntur

Guntur

External Examiner

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ACKNOWLEDGEMENT

It is our privilege to have Dr. M.RAMA RAO ,Professor in Department

of Civil Engineering , as our guide for this project work. We extend our heart-felt gratitude for

his effort and valuable guidance in bringing out this project successful.

We also thank Sri M.L.N.KRISHNA SAI, Asst.Professor in Department of

civil engineering, R.V.R& J.C college of engineering for his valuable suggestions and help in

carrying out this project work.

We thank one and all staff members of Civil Engineering department, senior students

for their help.

Finally, we thank all the unmentioned ones and invisible hand who helped in bringing

this project to present form.

ACCOMPLISHED BY:

L.SATISH KUMAR (Y9CE862)

M.MANOJ KUMAR (Y9CE864)

L.ANJANEYULU (Y9CE863)

P.VIJAYA RAMA RAJU (Y9CE882)

N.SUMAN KANTH (Y9CE881)

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CONTENTS

Page. no

1.Abstract 6

2.Introduction 7

2.1 Manufactured sand 8-13

2.2 Need for Manufactured sand

2.3 Market name for manufactured sand

2.4 Difference between Manufactured sand

and crushed dust

2.5 Manufacturing process of Manufactured sand

3.Review of literature: 14-15

3.1 General

3.2 Experimental conclusions made by different

researchers along with their study

4. Methodology of Experimental work 16-38

4.1 General

4.2 Tests on materials:

4.2.1 Cement

4.2.2 Fine aggregate

4.2.3 Coarse aggregate

4.2.4 Water

4.3 Standard Mix design

4.4 Specimen preparation

4.4.1 Design parameters

4.4.2 Mixing

4.4.3 Casting of specimens

4.4.4 Curing of specimens

4.5.Standard test procedures on concrete

4.5.1 Workability by slump cone test

4.5.2 Compressive strength test

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4.5.3 Flexural tensile strength test

4.5.4 Splitting tensile strength test

4.5.5 Durability test in acidic medium

5.Experimental results and Discussions 39-46

6.Future scope of project 47

7.Conclusions 48

8.References 49

9.Photographs taken during experiment 50-53

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1.ABSTRACT:

Concrete is the most widely used composite construction material. Fine

aggregate plays a very important role for imparting better properties to concrete in

its fresh and hardened state. Generally, river sand was used as fine aggregate for

construction. Due to the continuous mining of sand from riverbed led to the

depletion of river sand and it became a scarce material. Also, sand mining from

river bed caused a lot of environmental issues. As a substitute to river sand,

manufactured sand has been used.

In this present experimental study a comparative study has been carried

out to check the usability of manufactured sand in place of natural sand. This study

involves determination of some major properties of concrete like compressive

strength, split tensile strength, flexural tensile strength and durability in acidic

medium made of both the sands.

Based on proposed studies, quality of manufactured sand is equivalent to natural

sand in many respects, such as cleanliness, grading ,strength, angularity, specific

gravity. Conclusion have been arrived that manufactured sand produced from VSI

(vertical shaft impactor) is a suitable and viable substitute to river sand and could

be effectively used in making concrete which provides adequate strength and

durability for the concrete.

In the design of concrete structures, concrete is taken into account by taking its

compressive strength value. The compressive strength of the concrete made of

manufactured sand is observed to be very nearer to the strength of the concrete

made of natural sand in the present investigation, there by 100% replacement is

reasonable.

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2. INTRODUCTION

This chapter contains the general information about manufactured sand ,its origin,

need of manufactured in construction. It also includes the exact meaning of

manufactured sand , crushed dust, process of manufacturing by various machinery.

Natural sands are weathered and worn out particles of rocks

and are of various grades or size depending on the accounting of wearing. The

main natural and cheapest resource of sand is river. Dams are constructed on every

river hence these resources are erasing very fast. Now a days good sand is not

readily available, it should be transported from long distance. Those resources are

also exhausting very rapidly.

Sand is the one of main constituents of concrete making which is about 35%

of volume of concrete used in construction industry. Natural sand is mainly

excavated from river beds and always contain high percentage of in organic

materials, chlorides, sulphates, silt and clay that adversely affect the strength,

durability of concrete & reinforcing steel there by reducing the life of structure,

when concrete is used for buildings in aggressive environments, marine structures,

nuclear structures, tunnels, precast units, etc. Fine particles below 600 microns

must be at least 30 % to 50% for making concrete will give good results. Normally

these particles are not present in river sand up to required quantity. Digging sand,

from river bed in excess quantity is hazardous to environment. The deep pits dug in

the river bed, affects the ground water level. The sand in the mortar does not add

any strength but it is used as an adulterant for economy and with the same it

prevents the shrinkage and cracking of mortar in setting. The sand must be of

proper gradation (it should have particles from 150 to 4.75 mm in proper

proportion). When fine particles are in proper proportion, the sand will have less

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voids. The cement required will be less when there will be less void in sand. Such

sand will be more economical. Only sand manufactured by V.S.I. Crusher is

cubical and angular in shape. Sand made by other types of machines is flaky ,

which is troublesome in working. There is no plasticity in the mortar. Hence the

mason are not ready to work with machine made crushed stone sand. For the same

reason inferior river sand may be used. Manufacturing sand from jaw crusher, cone

crusher, roll crusher often contains high percentage of dust and have flaky particle.

Flaky and angular particles may produce harsh concrete, and may result in spongy

concrete. There is standard specification for Fine aggregates (Sand). It is divided in

four gradations. Generally known as Zone I, Zone II, Zone III and Zone IV. There

is sieve Designation for each grade. Gradation is made as per the use of the sand.

V.S.I can produce any zone of sand. But in case of natural sand quality varies from

location to location without any control.

2.1. Manufactured sand:

Manufactured sand is defined as a purpose made crushed fine

aggregate produced from a suitable source material. Production generally involves

Crushing, Screening and possibly Washing, separation into discrete fractions,

recombining and blending.

At the beginning manufactured sand produced (by Jaw crusher, cone

crusher, roll crusher, hammer mill) contains flaky and elongated particles. But now

manufactured sand produced from V.S.I (vertical shaft impactor) is a suitable and

viable substitute to river sand and could be effectively used in making concrete

which provides adequate strength and durability for the concrete.

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Having cubical shape, it effectively provides good bonding in

concrete. Grading of manufactured sand can be controlled i.e required zone of sand

can be obtained. Manufactured sand can be produced with zero fines. As it doesnt

contain silt and clay ,setting properties of cement are not altered. For big projects

where large quantity of aggregate is required ,Plants are established near the site so

that the cost of transportation can be reduced.

2.2. Need for Manufactured sand :

The Civil engineers, Architects , Builders, Contractors agrees

that the natural sand, which is available today, is deficient in many respect. It does

not contains the fine particles, in proper proportion as required. Presence of other

impurities such as coal, bones, shells, mica and silt etc makes it inferior for the use

in cement concrete. The decay of these materials, due to weathering effect,

shortens the life of the work. Now a days, Government have put ban on dragging

sand from river bed.

Due to dragging of the sand ,from river bed reduces the

water head, so less percolation of rain water in ground, which result in lower

ground water level. In some places it may be up to 600 ft deep. The roots of the

tree may not be able to get water. The water flowing in the river may be covered

with sand so it is less exposed to Sun. In the absence of sand, more water gets

evaporated due to direct sunlight. The rain water flowing in the river contains more

impurities. when it passes through sand bed it gets filtered. ( In water supply

schemes the water is filtered in sand bed only) If there is no sand in river- bed,

water will not be filtered. Such water may be harmful for drinking purpose.

Reduced water level in ground, may result in draught, even scarcity of drinking

water, so Government have to supply water by tanker. Which is more expensive

compared to the royalty collected for sand.

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Vastu Shastra:

Now a days Vastu Shastra is more popular, followed by

so many persons for constructing a house. As per Vastu shastra the Building

material must be free from traces of human body or animal body. The River sand

contains bones of human beings and animals. The shells are also one kind of bone.

It is not easy to take out all such things present in the river sand. The best solution

for this is to use Manufactured sand of good quality.

Cost:

Enormous growth of infrastructure in the country resulting in increased

use of river sand. Therefore, scarcity of sand effecting the cost of sand and hence

cost of construction.

Considering all the above facts, need for manufactured sand has

increased drastically. Therefore, it is necessary to replace natural sand in concrete

by an alternate material either partially or completely without compromising the

quality of concrete.

2.3.Market name for Manufactured sand.

It is being called in the market with different names like

Artificial sand(as it is artificially produced ), Robo sand(as it produced first by the

company named Robosilicon ,pvt, limited) ,crushed sand (as it is produced from

crushing),Rock sand ( as the origin is rock).

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2.4. Difference between manufactured sand and crushed dust:

There is an ambiguity between the two words manufactured sand and

Crushed dust. The actual meaning is given below which illustrates that the two are

entirely different.

Crushed dust is the waste product produced from the stone

quarries. The main aim of the stone quarry is to produce coarse aggregate(80mm-

4.75mm according to IS 383:1997) .The waste from these plants contain lot of

fines( passing through 75) along with flaky and elongated particles of size

ranging from 4.75mm to 75. If properly treated this can be used for producing

Manufactured sand . But treating this waste is an expensive work. Nutshell, it is a

by product. Manufactured sand is purposefully made from parent rock but it

doesnt contain fines(silt ,clay),instead it contains uniformly graded cubical

particles of size ranging from 4.75mm-150.

2.5 Manufacturing process:

Vertical Shaft Impactor principle is used for crushing bigger

particles, for shaping the crushed metal (giving better shape of the particle) and for

crushing fines aggregates below 4.75 mm. It is best machine Impactor is of cubical

shape. Such sand can be used for all types of construction work, Concreting,

Plastering etc and is better substitute to river sand. V.S.I. Crushers is a most

economical machine for Crushing Stone in Cubical shape and manufacturing

artificial sand. In this machine the particles are thrown at a high speed, those

particles colloid with each other and shatter in cubical particles. An Anvil ring,

Shelf ring (pigeon hole ring) are provided to get the particles edges grounded.

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The wear cost is a very important criteria in crushing process.

Wear cost of other crushing machines such as Roll crushers, Cone crushers,

H.S.I(Horizontal Shaft Impactor) is very high compared to V.S.I. Crushers. It is

about four to five times more that of VSI crusher. Rotopactor is a most economical

machine for manufacturing artificial sand. In this machine the stone are thrown at a

high speed, those particles colloid with each other and shatter in cubical particles.

Anvils or Shelf ring (pigeon hole ring) are provided. A rubbing action of particles

over pigeon ring, grounds the sharp edges and make the texture smooth.

In these machine, a specially designed pigeon ring is

provided which uses the residual kinetic energy in the particle and makes it revolve

and role and rub with each other in a circular path. This makes the shape of the

particles very good, and smooth. The sand manufactured can be of very fine to

course grade as per the requirement of the work. The sand manufacturing process

is dry. The process requires very less water that too only to settle down the residual

dust particles in colloidal state, emitted from the outlet. This machine can allow,

slightly wet grit for crushing. Other machines, Cone crusher, H.S.I. could not use

wet material, as it clogs the machine. V.S.I. crushers and Rotopactors are more

efficient and more economical in operation. Due to constant development and

research our machines are very sturdy and requires very less maintenance. It is the

result of our efforts for constant development the wear cost of our machine is least.

Manufacturing process involves the following three steps:

1. Crushing by VSI crusher.

2. Screening.

3. Washing.

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Crushing of stones in to aggregates by VSI, then fed to Rotopactor to crush

aggregates into sand to required grain sizes (as fines). Screening is done to

eliminate dust particles and Washing of sand eliminates very fine particles present

within. The end product will satisfy all the requirements of IS:383 and can be used

in Concrete & construction. The VSI Plants are available capacity up-to 400Ton

Per Hour(TPH). Only, sand manufactured by VSI crusher/ Rotopactor(shown in

the fig1,fig2) is cubical and angular in shape. Sand made by other types of

machines is flaky, which is troublesome in working. The Jaw crushers are

generally used for crushing stones in to metal/aggregates. Manufactured sand from

jaw crusher, cone crusher, roll crusher often contain higher percentage of dust and

have flaky particle.

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3.REVIEW OF LITERAURE

3.1.General:

Misra (1984) studied the effect of complete replacement of sand with

crushed sand (fine sand passing through 75). The percentage of water required to

produce mortar of same consistency is high for Robosand as compared to river

sand of same grading and same mix proportions. Hudson (1999) reported that

Concrete Manufactured with a high percentage of minus 75 micron material will

yield a more cohesive mix than concrete made with typical natural sand. Giridhar

(2000) have observed that the concrete prepared using crusher stone dust was

found to be relatively less workable than those compared with river sand and for

the concrete made with crusher dust, there is an increase of 6% strength split

tension and an increase of 20% strength in flexural tensile tension at 28 days for

M20 grade design mix. Rao et.al (2002) has found that as percentage of stone dust

increases the workability decreases in each grade of concrete, to compensate the

decrease in workability, some quantity of water and cement were added to get

normal workability. The percentage of increase in water is in the range of 5% to

7%.

Bhanuprabha,(2003) observed that the percentage of

weight for M20, M25 and M30 grade manufactured sand concrete increased in 5%

H2S04 and 5% Na2S03 acid compared to plain concrete and found to be as30.3%,

24.4%, 22.9%; and 5.3%, 2.2%,1.25% respectively. The negative sign

indicates less reduction in weight loss that means the concrete is slightly more

durable to sulphuric acid attack and sulphate attack when compared to river sand.

Dinesh Khare (2002) has reported that flexural tensile stress of the concrete

increases as percentage of Robo sand increases.

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3.2. Experimental studies conducted by different researchers along with their

study.

Bhikshma et.al(2009) conducted tests on 30 concrete cubes and 10

reinforced beams. They observed increase in compressive strengths by

6.89%, 10.76%, 17.24% and 20.24% for replacements of 25%,50%,75% and

100% of manufactured sand.

Having conducted different tests ULTRA TECH PVT LTD, arrived at

increased in compressive strength values.

According to the report given by Venu et.al from BITS PILANI , Hyderabad

the flexural strength of high performance concrete increases with increase in

silica fume and manufactured sand .

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4. METHODOLOGY OF EXPERIMENTAL WORK

4.1.General:

An experimental study is conducted to find 7 and 28 day Compressive ,

Flexural, Split tensile tests along with 60 days acid ponding test in M30 grade

concrete made of both Natural sand and Manufactured sand and the results were

compared for drawing a conclusion.

Methodology and experimental work involves the tests required to

ascertain the quality of materials for making concrete, designing the concrete mix,

preparation of specimens and different standard methods for testing the concrete .

4.2. Tests on materials:

Cement:

Ordinary Portland cement of 53 grade available in local market is used in the

investigation.The cement used has been tested for various properties as per

IS:4031-1988 and found to be confirming to various specifications as per IS:

12269-1987.The tests results on Ordinary Portland cement are shown in Table 1.

Table-1: Physical properties of Ordinary Portland cement of 53 grade:

S.no Property Test results

1 Normal consistency 30%

2 Specific gravity 3.047

3 Setting time

Initial setting time

Final setting time

35min

230min

4 Fineness of cement(IS sieve no 9) 3.5%

5 Compressive strength(1:3 sand mortar cubes)

7 days

28 days

37Mpa

53 Mpa

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Fine aggregate:

The locally available natural sand and machine made

manufactured sand are used as fine aggregate. It should be free from clay, silt,

organic impurities etc.,The sand is tested for various properties such as specific

gravity ,bulk density etc. in accordance with IS:2386-1963. The grading or particle

size distribution of fine aggregate shows that it is close to grading Zone II or

IS:383-1970 and details of sieve are shown in tables 2.1,2.2.

Table 2: Sieve analysis for fine aggregate

2.1 Natural sand:Wt taken=1000gm

Sieve no: Wt retained on

each sieve

% of wt

retained

Cumulative %

of wt retained

Cumulative %

of passing

10 mm 0 0 0 100

4.75 mm 10 1 1 99

2.36 mm 10 1 2 98

1.18 mm 140 14 16 84

600 215 21.5 37.5 62.5

300 535 53.5 91 9

150 70 7 98 2

75 20 2 100 0

Total 1000g

This fine aggregate is confirming to Zone II according to IS:383

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2.2 Manufactured sand :Wt taken 1000gm

Sieve no: Wt retained on

each sieve

% of wt

retained

Cumulative %

of wt retained

Cumulative %

of passing

10 mm 0 0 0 100

4.75 mm 5 0.5 0.5 99.5

2.36 mm 95 9.5 10 90

1.18 mm 250 25 35 65

600 116 11.6 46.6 54.4

300 270 27 73.6 26.4

150 135 13.5 87.1 12.9

75 129 12.9 100 0

Total 1000g

This is Fine aggregate is confirming to Zone-II according to IS-383

Coarse aggregate:

The machine crushed annular granite metal of average size of 40mm

is used as a coare aggregate . It should be free from impurities such as dust, clay

particles , organic matter etc the fine and coarse aggregate are tested for various

properties as shown in table. The grading or particle size distribution of coarse

aggregate shown close to average size of 40mm as per IS:383-1970 and detals of

sieve analysis are shown in table 3.

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Table 3: Sieve analysis for coarse aggregate : wt taken=10kg

Sieve size Wt retained on

each sieve

% wt retained Cumulatve %

of wt retained

Cumulative %

of passing

80 0 0 0 100

40 0 0 0 100

20 2400 24 24 76

10 640 64.6 88.6 11.4

10 mm passing 1140

10000 gm

This values are confirming to 40mm (average size of the aggregate) according to

IS:383-2007.

Water:

Water used for mixing and curing shall be clean and free from injurious

amount of oils, acids, alkalies, salts ,organic materials or other substances. They

may be deleterious to concrete. Portable water is used for mixing as well as curing

of concrete as prescribed in IS:456:2000.

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4.3.Standard concrete Mix design:

Mix design can be defined as the process of selecting suitable ingrediants

of concrete and determining their relative proportions with the object of producing

concrete of certain minimum strength and durability as economical as possible.

Concrete mix design for M30 grade of concrete using both natural sand

and manufactured sand was done according to IS:10262-2009 and the final

proportion are given in the table 4.1,4.2.

Formulation of mix design procedure:

Target mean strength: The target mean strength(fck) is calculated as follows.

Fck=fck+(t x s) with usual BIS notations . When adequate data are not available to

establish s ,the fck value can be determined from the following table.

IS:10262-2009

Specified characteristic compressive

strength,fck(Mpa)

Target mean compressive strength

Fck(Mpa)

Less than 20.5

20.5-34.5

More than 34.5

fck+6.9

fck+8.3

fck+9.7

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Selection of Maximum size of coarse aggregate:

The maximum size of coarse aggregate is selected from the

following table .

IS10262:2009

Required concrete strength(Mpa) Maximum aggregate size (mm)

Less than 62

Greater than or equal to 62

20-25

10-12.5

Estimation of free water content:

The water content to obtain desired workability depends upon the

amount of water, super plasticizers and its characteristics. However , the saturation

point of super plasticizer is known and then the water dosage is given below. If the

saturation point is not known, it is suggested that the water content of 145 lit /cu.m

shall be taken to start with.

Determination of minimum water dosage:

IS:10262-2009

Saturation

point(%)

0.6 0.8 1 1.2 1.4

Water

dosage(lit/cu.m)

120-125 125-135 135-145 145-155 155-165

Estimation of air content:

The air content to be expected is obtained from the following table for

maximum size of coarse aggregate used . However it is suggested that an initial

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estimate of entrapped air content shall be taken as 1.5% or less, and then adjusting

it on the basis of the results obtained with trial mix.

IS10262-2009

Nominal maximum size of coarse

aggregate (mm)

Entrapped air as percentage of volume

of concrete

10 2.5

12.5 2.0

20 1.5

25 1

Selection of coarse aggregate content:

The coarse aggregate is obtained from table as a function of

typical particle shape . If there is any doubt about the shape of coarse aggregate or

if its shape is known ,it is suggested that a coarse aggregate content of

1000kg/cu.m concrete shall be take to start with.

Coarse aggregate content:

Coarse

aggregate

particle shape

Elongated or

flat

Average Cubic Rounded

Coarse

aggregate

content(kg/cu.m)

950-1000 1000-1050 1050-1100 1100-1150

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Selection of water binder ratio:

The water binder (w/b) ratio for the target mean compressive strength is

chosen from below graph, the w/b ratio verses compressive strength. The w/b is so

chosen is checked against limiting w/b ratio for the requirement of durability.

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Calculation of binder content:

The binder or cementations contents per cu.m of concrete is caluculated from

the w/b ratio and quantity of water content per cu.m of concrete. Assuming the

percentage of replacement of cement by silica fume content is obtained from the

total binder contents. The remaining binder content is composed of cement. The

cement content is so calculated and is checked against the minimum cement

content for requirement of durability above values are adopted.

Estimation of fine aggregate contents:

The absolute volume of fine aggregate is obtained from the

following equation .

Vfa=1000-(Vw+Mc/Sc+Msf/Ssf+Mca/Sca+Mfa/Sfa+Vsol+Vea)

Where

Vfa=Absolute volume of F.A in lit/cu.m of concrete

Vw=Volume of water in lit/cu.m of concrete.

Mc= mass of cement kg/cu.m of concrete.

Sc=Specific gravity of cement

Msf,Mca=Total masses of Sf and CA in kg/cu.m of concrete.

Sca,Ssf=specific gravities of saturated surface dry coarse aggregate and silica fume

respectively.

Vsol,Vea=Volume of solids in the super plastisizer and entrapped air lit/cu.m

concrete respectively.

The fine aggretgate conctent per unit volume of concrete is obtained by

multiplying the absolute volume of fine aggregate and the specific gravity of the

finr aggregate .

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PREPARATION OF THE SPECIMENS:

Design parameters :( for M30 grade concrete)

Parameters Natural sand Manufactured sand

Average size of aggregate 40 mm 40mm

Degree of Workability Slump(100mm) Slump(100mm)

Degree of quality of

control

Good Good

Type of exposure Severe Severe

Compressive strength of

cement

53 N/mm2 53N/mm2

Selection of W/c ratio 0.45 0.4

Mixing:

Pan- mixing is adopted throughout the experimental work. First the

materials cement, Fine aggregate, coarse aggregate, weighed accurately.pan mixer

is used as a capacity of 1 cu.f t. The drum is made of steel plates with a number of

blades put in inclined position in the drum. As the drum rotates, the materials

encountered resistance from the blades and these disturbing effects helps in good

mixing of ingredients. The mixing is continued until there is a uniform distribution

of materials and the mass uniform in color and consistency.

5-10% of total quantity of water required for mixing, sufficient to

wet the drum thoroughly, shall be introduced before the other ingredients in order

to prevent any chocking of cement on the blades or the sides of the mixer. After

mixing the concrete is tested for workability using slump cone test.

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4.4. Casting of specimens:

For casting the cubes, cylinder and beam specimens a standard

cast iron metal moulds of size 150x150x150 mm cubes , 150 mm diameter and

300mm height cylinders and beams of size 150x150x700mm are used . The mould

have been cleaned off dust particles and applied with mineral oil on all sides ,

before concrete is poured into the mould. Thoroughly mixed concrete is filled into

the mould in three layers of equal height followed by vibration with needle

vibrator. Excess concrete is removed with trovel and top surface is finished to

smooth level.

Compaction of concrete:

Compaction of concrete is a process adopted for expelling

the entrapped air from the concrete. In the process of placing and mixing of the

concrete , air is likely to get entrapped in the concrete. If this air is not removed

fully, the concrete looses strength considerably.

In order to achieve full compaction and maximum density with reasonable

compacting efforts available at the site, it is necessary to use a mix with adequate

workability. In the present investigation, the internal vibration is used for

compacting the concrete.

Needle vibrator consists of a steel tube, which is inserted in fresh concrete.

Theirs steel tube is connected to an electric mortar through a flexible tube. The size

of poker is 40 mm diameter. The frequency of vibration is about 3000 rpm.

Compaction of concrete by vibration makes the concrete better quality, higher

strength with given cement content with less mixing water.

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Curing of specimens:

Curing is the process of preventing the loss of moisture from

the concrete whilst maintaining a satisfactory temperature regime. More

elaborately, curing is defined as the process of maintaining satisfactory moisture

content and a favorable temperature

in concrete during the period immediately following placement, so that hydration

of cement may continue until the desired properties are developed to sufficient

degree to meet the requirement at service.

After casting, the moulded specimens are stored in the laboratory free from

vibration, in moist air and room temperature for 24 hours from the time at addition

of water to the dry ingredients. After this period, the specimens are removed from

the moulds, immediately submerged in clean fresh water tank. The water in which

specimens are submerged are renewed at every 7 days and maintained at a

temperature of 27+_2 degree. The specimens are cured for 7 days and 28 days

respectively.

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4.5 Standard test procedures on concrete:

WORKBILITY BY SLUMP CONE TEST: (According to IS: 1199 1959)

Unsupported concrete, when it is FRESH, will flow to the

sides and a sinking in height will take place. This vertical settlement is known as

SLUMP. Slump is a measure indicating the consistency or workability of cement

concrete. It gives an idea of water content needed for concrete to be used for

different works. A concrete is said to be workable if it can be easily mixed and

easily placed, compacted and finished. A workable concrete should not show any

segregation or bleeding. Slump increases as water-cement ratio increases.

Slump test is the most commonly used method of measuring consistency of

concrete which can be employed either in laboratory or in site of work. It is not a

suitable method for very wet or very dry concrete. It does not measure all factors

contributing to workability, nor it is always representative of the place-ability of

concrete. However, it is used conveniently as a control test and gives an indication

of the uniformity of concrete from batch to batch. Repeated batches of the same

mix, brought to the same slump, will have the same water content and W/c ratio,

provided the weights of aggregate, cement and admixtures are uniform and

aggregate grading is within acceptable limits.

Apparatus consists of Slump cone, tray for mixing

concrete, trowel, tamping rod, steel rule, measuring jar, weighing platform

machine, spatula. The apparatus for conducting the slump test essentially consists

of metallic mould in the form of a frustum of a cone having the dimensions as

under:

29

Bottom diameter = 20cm

Top diameter = 10 cm

Height = 30 cm

The thickness of the metallic sheet for the mould should not be thinner than

1.6mm. For tamping the concrete, a steely tamping rod 16mm diameter; 0.6m long

with bullet end is used.

PROCEDURE:

Four mixes are to be prepared with W/c ratio (by weight) of 0.5, 0.6, 0.7 and 0.8

respectively and for each mix take 10 Kg. of coarse aggregate, 5 Kg. of sand and

2.5 Kg. of cement. Then the mix proportions are 1:2:4 (Cement : Sand : Coarse

Aggregate). If needed, slump values of other mixes i.e. mixes of different

proportions can also be found.

The internal surface of the mould is thoroughly cleaned and freed from superfluous

moisture and any old set concrete before commencing the test. Fix slump cone to

the base. The base should be smooth, horizontal, rigid and non-absorbent surface.

Apply lubricating oil to the inside walls of slump cone so that concrete is

prevented from sticking to the walls of the slump cone.

1) Measure the height of the slump cone. Let it be "h1" cm.

2) Preparation of concrete mix: First mix cement and sand in dry state till a

mixture of uniform colour is obtained and to this mixture add coarse aggregate

and again mix all the three ingredients. Then add water according to the given

W/c ratio and prepare a homogeneous mix.

3) The mould is then filled in four layers, each approximately (1/4) of the height of

the mould. Each layer is tamped 25 times by the tamping rod taking care to

30

distribute the strokes evenly over the cross-section. For the second and

subsequent layers, the tamping rod should penetrate into the underlying layer.

4) After the top layer has been rodded, strike off the top with a trowel, so that the

mould is exactly filled.

5) The mould is removed from the concrete immediately by raising it slowly and

carefully in a vertical direction.

6) As soon as the concrete settlement comes to a stop, measure the subsidence of

concrete i.e. the difference in level between the height of the mould and that of

the highest point of the subsided concrete (OR) measure the height of the

concrete and let it be "h2" cm. The difference between (hi) and (h2) gives the

slump.

7) Repeat the procedure for different W/c ratios.

NOTE: Any slump specimen which collapses or shears off laterally gives incorrect

results and if this occurs, the test is repeated.

True slump Shear slump Collapse slump

31

TESTING OF CUBES FOR COMPRESSIVE STRENGTH:(According to IS:516-

1959)

In the design of concrete mixes,the compressive strength of concrete is

generally the main target since it usually represents an overall picture of quality of

concrete.The compressive strength is the maximum load per unit area sustained by

a concrete before failure under compression.since the strength development of

concrete depends on both temperature .it can be said the strength is a function of

summation of product of time and temperature .this summation is called maturity

of concrete.

The cube specimens cured as above are tested as per standard procedure after

removal from the curing tank and allowed to a dry under shade. The cube

specimens tested under microprocessor based compression testing machine of

2000KN capacity. The results are tabulated in table.

SPLITTING TENSILE STRENGTH:(According to IS :516-1959 )

Cylinder Splitting Tension Test: This is also sometimes referred as, Brazilian

Test. This test was developed in Brazil in 1943. At about the same time this was

also independently developed in Japan.

The test is carried out by placing a cylindrical specimen horizontally between the

loading surfaces of a compression testing machine and the load is applied until

failure of the cylinder, along the vertical diameter. Figure 10.6 shows the test

specimen and the stress pattern in the cylinder respectively.

When the load is applied along the generatrix, an element on the vertical

diameter of the cylinder is subjected to a vertical compressive stress of

32

1

2 2-

rDr

D

pLD

P

and a horizontal stress of LD

P

2

where, P is the compressive load on the cylinder

L is the length of cylinder

D is its diameter and r and (D r) are the distances of the elements from

the two loads respectively.

The loading condition produces a high compressive stress immediately below the

two generators to which the load is applied. But the larger portion corresponding

to depth is subjected to a uniform tensile stress acting horizontally. It is estimated

that the compressive stress is acting for about 1/6 depth and the remaining 5/6

depth is subjected to tension.

In order to reduce the magnitude of the high compression stresses near the

points of application of the load, narrow packing strips of suitable material such as

plywood are placed between the specimen and loading platens of the testing

machine. The packing strips should be soft enough to allow distribution of load

over a reasonable area, yet narrow and thin enough to prevent large contact area.

Normally, a plywood strip of 25 mm wide, 3 mm thick and 30 cm long is used.

The main advantage of this method is that the same type of specimen and the

same testing machine as are used for the compression test can be employed for this

test. That is why this test is gaining popularity. The splitting test is simple to

perform and gives more uniform results than other tension tests. Strength

determined in the splitting test is believed to be closer to the true tensile strength of

33

concrete, than the modulus of rupture. Splitting strength gives about 5 to 12%

higher value than the direct tensile strength.

DETERMINATION OF FLEXURAL STRENGTH:(According to IS:516-1959)

Direct measurement of tensile strength of concrete is

difficult. Neither specimens nor testing apparatus have been designed which

assure uniform distribution of the pull applied to the concrete. While a number

of investigations involving the direct measurement of tensile strength have been

made, beam tests are found to be dependable to measure flexural strength property

of concrete.

The value of the modulus of rupture (extreme fibre stress in bending)

depends on the dimension of the beam and manner of loading. The systems of

loading used in finding out the flexural tension are central point loading and third

point loading. In the central point loading, maximum fiber stress will come below

the point of loading where the bending moment is maximum. In case of

symmetrical two point loading, the critical crack may appear at any section, not

strong enough to resist the stress within the middle third, where the bending

moment is maximum. It can be expected that the two point loading will yield a

lower value of the modulus of rupture than the centre point loading. Figure 10.4

34

shows the modulus of rupture of beams of different sizes subjected to centre point

and third point loading. I.S. 516-1959, specifies two point loading. The details of

the specimen and procedure are described in the succeeding paragraphs.

The standard size of the specimens are 15 x 15 x 70 cm. Alternatively, if the

largest nominal size of the aggregate does not exceed 20 mm, specimens 10 x 10 x

50 cm may be used.

The mould should be of metal, preferably steel or cast iron and the metal

should be of sufficient thickness to prevent spreading or warping. The mould

should be constructed with the longer dimension horizontal and in such a manner

as to facilitate the removal of the moulded specimens without damage.

The tamping bar should be a steel bar weighing 2 kg. 40 cm long and should

have a ramming face 25 mm square.

The testing machine may be of any reliable type of sufficient capacity for the

tests and capable of applying the load at the rate specified. The permissible errors

should not be greater that 1.5 per cent of the applied load for commercial type of

use. The bed of the testing machine should be provided with two steel rollers. 38

mm in diameter, on which the specimen is to be supported, and these rollers should

be so mounted that the distance from centre to centre is 60 mm for 15 cm specimen

or 40 cm for 10.0 cm specimens. The load is applied through two similar rollers

mounted at the third points of the supporting span, that is spaced at 20 or 13.3 cm

centre to centre. The load is divided equally between the two loading rollers, and

all rollers are mounted in such a manner that the load is applied axially and without

subjecting specimen to any torsional stresses or restrains. The loading set up is

shown in Fig. 10.5.

35

Procedure:

Test specimens are stored in water for 28 days before testing. They are tested

immediately on removal from the water whilst they are still in a wet condition.

The dimensions of each specimen should be noted before testing. No preparation

of the surfaces is required.

Placing the Specimen in the Testing Machine :

The bearing surfaces of the supporting and loading rollers are wiped clean, and

any loose sand or other material removed from the surfaces of the specimen where

they are to make contact with the rollers. The specimen is then placed in the

machine in such a manner that the load is applied to the uppermost surface as cast

in the mould, along two lines spaced 20.0 or 13.3 cm apart. The axis of the

specimen is carefully aligned with the axis of the loading device. No packing is

used between the bearing surfaces of the specimen and the rollers. The load is

applied without shock and increasing continuously at a rate such that the extreme

fibre stress increases at approximately 0.7 kg/sq.cm/min that is, at a rate of loading

of 400 kg/min for the 15.0 cm specimens and at a rate of 180 kg/min for the 10.0

cm specimens. The load is increased until the specimen fails, and the maximum

load applied to the specimen during the test is recorded. The appearance of the

fractured faces of concrete and any unusual features in the type of failure is noted.

The flexural strength of the specimen is expressed as the modulus of rupture fb

which if a equals the distance between the line of fracture and the nearer support,

measured on the centre line of the tensile side of the specimen, in cm, is calculated

to the nearest 0.05 MPa as follows:

2

db

lPfb

36

When a is greater than 20.0 cm for 15.0 cm specimen or greater than 13.3

cm for a 10.0 cm specimen, or

2

3

db

apfb

when a is less than 20.0 cm but greater than 17.0 cm

for 15.0 specimen, or less than 13.3 cm but greater than 11.0 cm for a 10.0 cm

specimen where

b = measured width in cm of the specimen.

DURABILITY OF CONCRETE :

A durable concrete is one that performs satisfactorily in the working

environment during its anticipated exposure conditions during service. The

materials and mix proportions specified and used should be such as to maintain its

integrity and if applicable, to protect embedded metal from corrosion. One of the

main characteristics influencing the durability of concrete is its permeability to the

ingress of the water , oxygen, carbon dioxide, chloride , sulphate constituents and

workmanship in making the concrete with normal-weight aggregates a suitably,

low permeability is achieved by having an adequate cement content , sufficiently

37

low, free w/c ratio, by ensuring complete compaction of concrete and adequate

curing. The factors influencing durability include

1.Environment.

2. Cover to embedded steel.

3. The type and quality of constituent materials .

4. Cement content and w/c ratio of concrete.

5. Workmanship, to obtain full compaction and efficient curing.

6. Shape and size of member.

The degree of exposure anticipated for the concrete during its service

life together with other relevant factors relating to mix composition, workmanship,

design and detailing should be considered . All relevant requirements for durability

of concrete as specified in IS456-2000.

In the present , investigation carried out to study the durability

characteristics of concrete specimens of size150x150x150 mm subjected to acid

attack.

Acid attack on concrete:

First of all , concrete containing Portland cement , being

highly alkaline, is not resistant to attack by strong acids or compounds which may

convert to acids .Chemical attack of concrete occurs by way of decomposition of

the products of hydration and formation of new compound , which, if soluble , may

be leached out and if not soluble, may be disruptive insitu. The attacking

compounds must be in solution. The most vulnerable cement hydrate is

Ca(OH)2,but C-S-H can also be attacked calcareous aggregate are also vulnerable.

Concrete can be attacked by liquids with Ph value below 6.5 but the attack is

severe only at Ph below 5.5, If below4.5 , the attack is very severe.

38

Acids first react with free lime of concrete forming calcium salts

and later on attack the hydro silicates and hydro aluminates forming. The

corresponding calcium salts, whose solubility will govern the extent of

deterioration caused to the concrete. In the present investigation , concrete

specimens of size 150x150x150 mm are immersed in 5% H2SO4 solution. The

deterioration of concrete specimens is presented in the form of % reduction in

weight of concrete specimens.

39

5. Experimental results and discussions:

Observed Specific gravities of fine and coarse aggregates:

S.no Material Specific gravity

1 Natural sand 2.66

2 Manufactured sand 2.55

3 Coarse aggregate 2.78

Comparison of tests results of natural sand with artificial sand:

Specific gravity:

The specific gravity values from the table indicates

that the specific gravity of natural sand is more than that of artificial

sand. Since the specific gravity of natural sand is more, corresponding

weight of cubes of size 150x150x150 mm made from this sand is also

more than weights of cubes made of robo sand .weights of cubes made

of both sands can be observed in table .For the given volume of concrete

quantity of manufactured sand required is more compared to

requirement of natural sand.

40

Bulking of fine aggregate ( Both for natural sand and Manufactured

sand)

% of water Bulking of natural sand Bulking of manufactured

sand

0 21.3 20.3

1 23.9 23.5

2 24.8 26.6

3 25.3 27.6

4 25.6 27.8

5 25.7 27.2

6 25.8 27

7 25 26.9

8 24 26.8

From the above table up to 4% the bulking is observed to be increased. The

bulking values from the table shows that the bulking of artificial sand is more than

natural sand. Thereby, Mix design by volume batching is difficult with artificial

sand.

41

MIX DESIGN ACCORDING TO IS 10262-2009

(For natural sand)

DESIGN STIPULATIONS : 1.Grade designation. M30 fck 30.000 Mpa

2.Type of cement. OPC

3.Maximum nominal size of the

aggregate . 40mm

4.Minimun cement content.

330

kg/cu.m

5.Maximum water cement ratio. 0.45

from

IS456

6.Workability. 100mm slump

7.Exposure conditions. severe

8.Method of concrete placing. -

9.Degree of super vision. good

10.Type of aggregate. Angular ballast

11.maximum cement content. 450 kg/cu.m

12.Standard deviation. 5 (based on the grade of the

13.Specific gravity of cement 3.047

concrete)

14.Specific gravity of fine aggregate: 2.66

15.Specific gravity of coarse aggregate: 2.78

16.Density of dmixture if used: 1

Procedure for mix design:

a.Target mean strength(fck'): 38.25 N/mm2

b.w/c ratio: 0.4 (Based on experience)

c.Maximum water content: 165 lit (Extra percent of

Estimated water content: 174.9 lit water required )

d.Admixture content: 0

6.000

e.Cement content: 437.25 kg/m3

f.Volume of coarse of aggregate per uit

volume of

total aggrgate: 0.71 (for zone- 2 from table 3 of IS10262

correction for the required water

cement ratio : 0.73 for water cement ratio of 0.5 )

percentage of reduction for pumpable

concrete: 10

% volume of coarse aggregate: 0.657

g.% Volume of fine aggregate 0.343

Mix calculations :

42

Volume of concete: 1 m3

Volume of cement: 0.143502 m3

volume of water: 0.1749 m3

volume of admixtures used if any: 0 m3

volume of all in aggregate: 0.681598 m3

mass of coarse aggregate: 1244.912 kg/m3

mass of fine aggregate: 621.8766 kg/m3

Materials: water cement

fine

.aggregate coarse.aggregate

Quantities: 174.9 437.25 621.877 1244.912

Ratio: 0.4 1 1.422 2.847

MIX DESIGN ACCORDING TO IS 10262-2009( For

Manufactured sand)

DESIGN STIPULATIONS : 1.Grade designation. M30 fck 30.000 Mpa

2.Type of cement. OPC

3.Maximum nominal size of the

aggregate . 40mm

4.Minimun cement content. 330 kg/cu.m

5.Maximum water cement ratio. 0.45

from

IS456

6.Workability. 100mm slump

7.Exposure conditions. severe

8.Method of concrete placing.

9.Degree of super vision. good

10.Type of aggregate. Angular ballast

11.maximum cement content. 450kg/cu.m

12.Standard deviation. 5 (based on the grade of the

13.Specific gravity of cement 3.047

concrete)

14.Specific gravity of fine aggregate: 2.5

15.Specific gravity of coarse aggregate: 2.78

16.Density of dmixture if used: 1

43

Procedure for mix design:(

a.Target mean strength(fck'): 38.25 N/mm2

b. w/c ratio: 0.4

(Based on

experience)

c. Maximum water content: 165 lit (Extra percent of

Estimated water content: 174.9 lit water required

d.Admixture content: 0

6.000 )

e.Cement content: 437.25 kg/m3

f.Volume of coarse of aggregate per uit volume of

total aggrgate: 0.71 (for zone- 2 from table 3 of IS10262

correction for the required water cement

ratio : 0.73 for water cement ratio of 0.5 )

percentage of reduction for pumpable

concrete: 10

% volume of coarse aggregate: 0.657

g.% Volume of fine aggregate 0.343

Mix calculations :

Volume of concrete: 1 m3

Volume of cement: 0.143502 m3 volume of water: 0.1749 m3 volume of admixtures used if any: 0 m3 volume of all in aggregate: 0.681598 m3 mass of coarse aggregate: 1244.912 kg/m3 mass of fine aggregate: 584.4705 kg/m3

Materials: water cement fine

.aggregate coarse.aggregate

Quantities: 174.9 437.25 584.470 1244.912

Ratio: 0.4 1 1.337 2.847

44

Workability by Slump cone method:

W/c ratio Slump in mm for

manufactured sand

Slump in mm for natural

sand

0.4 10 10

0.425 14 17

0.45 20 40

0.5 Collapsed Collapsed

At low water/ cement ratios , the workability of concrete made of both sands is

more or less same. But , as the w/c ratio increases, the natural sand was observed to

be highly workable than artificial sand. So, where ever high workability is

required, it is better to use natural sand ( i.e congested reinforcement and pump

able concrete). And where requirement workability is low, it is always advised to

use manufactured sand as it is economical. ( i.e laying of concrete payments).

Compressive strength values of concrete made of both the sands.

Concrete

made of

Cube1 Cube2 Cube3 Average

Natural sand

At 7 days

At 28 days

930 KN

960 KN

1200KN

1200KN

820KN

1000KN

983.33KN(43.7 MPa)

1053KN(46.8MPa)

Manufactured

sand

At 7days

At 28 days

850 KN

900 KN

900 KN

1050 KN

920 KN

1300 KN

890 KN(39.56 MPa)

1083 KN(48.51 MPa)

45

At the beginning, i.e at 7 days the strength of the concrete made of manufactured

sand is less than that of natural sand. But as the days of curing increases , the

strength of concrete cubes made of both sands are found more or less equal. As

compressive strength is the main property of the concrete that is considered in

design, we can replace natural sand with manufactured sand completely in making

concrete.

Flexural strength of concrete:

Concrete made of Beam1 Beam2 Average

Natural sand

At 28 days

3700 kgf 3700 kgf 3700 kgf(37kN)

Manufactured sand

At 28 days

3400 kgf 2940 kgf 3170 kgf(31.7 kN)

Splitting tensile strength of concrete:

Concrete made of Cylinder 1 Cylinder 2 Average

Natural sand

At 28 days

230 kN 230 kN 230 kN

Manufactured sand

At28 days

164 kN 188 kN 176 kN

The values of flexural and splitting tensile strengths of concrete

made of natural sand were found to be slightly more than the values of concrete

made of artificial sand .In any structural member, as the tensile stresses are taken

by steel to the greater extent, very low stresses are allowed to act on the concrete.

So, artificial sand can be used in concrete.

46

Durability tests made on both sands:

A1, A2, A3 are made of manufactured sand,

S1, S2, S3 are made of Natural sand

Name of the cube Initial weights Final Weights

Cube A1 8.72 kg 7.97 kg

Cube A2 8.86 kg 7.826 kg

Cube A3 8.65 kg 7.684 kg

Cube S1 8.74 kg 7.608 kg

Cube S2 8.62 kg 7.71 kg

Cube S3 8.57 kg 7.535 kg

Percentage loss of weight for natural sand after 60 days=10.48%

Percentage loss of weight for manufactured sand after 60 days=11.86%

Percentage loss is more or less equal for manufactured sand and

natural sand. So there is no durability problem with manufactured sand.

47

7. Future scope of work:

Replacing natural sand with different % of manufactured sand so that clear

variation of strength can be plotted as well as optimum amount can also be

determined.

Conducting investigation for M40, M50 and also for high strength concrete.

Conducting chloride penetration test and water absorption tests on concrete

to ensure adequate durability.

Suitability of manufactured sand must be ascertained for plastering.

48

8. Conclusions:

100% replacement is reasonable where there is low workability requirement.

And where there is high workability requirement, partial replacement can be

made keeping in view the strength and economy.

Strength criteria can be fully ascertained with 100% replacement of natural

sand with manufactured sand.

For big projects like highways, establishing a plant leads to economy as they

require large amount of fine aggregate.

River beds can be safeguarded by reducing the excavations for natural sand

49

9. References:

Bhanuprabha(2003).Studies on use of manufactured sand as Fine

Aggregate M. Tech dissertation, submitted to JNTU, Hyderabad, India .

Bhikshma V. Nitturkar,K and Venkatesham,Y(2009), Investigations on

mechanical properties of high strength silica fume concrete. Asian journal

of civil engineering (building and

housing) Vol. 10, no. 3. pp.335-346.

Dinesh Khare(2002)., Marvelous properties of Stone Crusher dust: A waste

by-product of tone crushers, National conference on Advances of

construction material, Hamirpur (H.P.), India. pp:189 to 195.

Giridhar, V(2000)., Strength characteristics of concrete using crusher stone

dust as fine aggregate, 63rd Annual General meeting, Hyderabad. pp: 11-

15. Hudson, B.P.(1999), Manufactured sand for concrete, ICJ, August

1999.

Misra, V.H(1984)., Use of Stone dust from crusher in cement and sand

Mortar ICJ, August 1984.

Saeed Ahmad and Shahid Mahmood(2008) , Effects of crushed and Natural

Sand on the properties of freshand Hardened concrete, Our World in

Concrete & Structures.

Srinivasa Rao, P., Seshagiri Rao, M.V. and Sravana.(2002), Effect of

crusher stone dust on some properties of concrete, National conference on

advances in construction materials, Hamirpur. pp:196-201.

Ultratech websites.(www.vsicrushers.com www.robosilicon.com).

50

10.Photo graphs taken during experiments:

CUBES IMMERSED IN ACID AT 5% CONCENTRATON(H2SO4)

51

CURING OF BEAMS, CUBES AND CYLINDERS.

52

TESTNIG OF CUBES FOR DETERMINING COMPRESSIVE

STRENGTH.

53

POURING OF ACID TO MAINTAIN CONSTANT ACIDITY AT

REGULAAR INTERVAL OF 5 DAYS

54

55