Comparitive Strength & Cost of Concrete

8/10/2019 Comparitive Strength & Cost of Concrete

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Comparative strength & cost of concrete by mix design & farma mix Design

CHAPTER: 1

INTRODUCTION

Concrete is by far the most widely used construction-material today. Cementmortar and concrete are the most widely used construction materials. It is difficult to

point out another material of construction which is as versatile as concrete. It is

material of choice where strength, permanence, durability, impermeability, fire

resistance and abrasion resistance are required. The versatility and mouldability of

this material, its high compressive strength, and the invention of the reinforcing

techniques for resisting against its low tensile strength have contributed largely to its

widespread use. It is interesting to note that from the same ingredients good quality

concrete and bad quality concrete can be obtained. This is mainly because the quality

of the concrete depends much, perhaps more, on the man on the job as, on the

constituent materials. The difference between good concrete and bad concrete lies in

quality control. Etensive research wor! has been carried out on the materials and

also on the methods used for concrete ma!ing. "till, not many men, on the job seem to

ma!e use of the !nown techniques for ma!ing good concrete which is necessary for

achieving strong, durable, and economical construction. In any country, construction

accounts for #$% of the plan outlay. &ut of this cement and cement product would

account for more than '$%. Today in India the annual consumption of cement is in

the order of (( million tones.

Concrete is a site made material unli!e other materials of construction and as

such can vary to a great etent in its quality, properties and performance owing to the

use of natural materials ecept cement. )rom materials of varying properties, to ma!e

concrete of stipulated qualities, an intimate !nowledge of the interaction of various

ingredients that go into the ma!ing of concrete is required to be !nown, both in

plastic condition and in the hardened condition. This !nowledge is necessary for

concrete technologists as well as for site engineers.

*n aesthetically pleasing and durable structure is indicative of the human

s!ill in design, construction and maintenance. There has been si+able refinement in

the design process with the advent of computers and further development in the

software industry. echani+ation of concrete construction in large projects has also

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delivered successful results, but there is a still need to improve the s!ill of manpower

involving small projects so as to impart quality finish and durability. In fact attaining

quality does not require any additional resources but differ involvement of

manpower. Concrete quality hinges on the selection of various ingredients in

concrete followed by design mi. ost of the collapses that too! place during the

huj Earthqua!e of anuary (#, ($$/ were due to faulty design and construction

techniques. Improperly constructed buildings showed several distresses or collapsed

partially resulting in large scale destructions and severe damage to human lives and

structures.

The construction industry has large number of labourers engaged in wor! but

this huge labour force is unorgani+ed. 0nfortunately they receive only rudimentary

training in construction practice. The need has been felt to conduct training for such

wor!ers to produce good quality concrete wherever it is used. This investment on

training is li!ely to compensate suitably with its dividends in times of good and

durable quality.

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CHAPTER: 2

CEMENT CONCRETE

3.1. General:

Concrete, the structural material, is a miture of binder and filler, the binder being the

1ortland cement and water, the filler being the aggregates coarse and fine and can be

shown in fig. /.

Concrete, when it is fresh, should be wor!able and at the same time be

cohesive. 2or!ability is required to compact the fresh concrete and cohesiveness is

required to avoid segregation while transporting, placing and compacting. In the

hardened state, concrete should have sufficient strength, resistant to abrasion,

impermeability to resist weathering, chemical attac! and corrosion.

To obtain the required properties in fresh and hardened concrete good

construction practices have to be followed. 3ood construction practices necessarily

involve proper selection and proportioning of its constituents.

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3.2. Concrete Constituents:

Ceent:

Cement is made from calcareous materials li!e limestone and argillaceous

material li!e clay. The process consists of grinding the raw materials, miing them in

desired proportion, burning them in a rotary !iln at about /4$$5C to form clin!ers.

These clin!ers are allowed to cool and finely ground with addition of small quantity

of gypsum. This product is the 1ortland cement. y suitable alteration in the

proportion of raw material, initially or blending po++olonic materials on the later

stage, various types of cement could be made suitable for specific needs. 6ere are the

different types of cement and their areas of usage.

Di!!erent t"#es o! ceent:

Or$inar" Portlan$ ceent:

3rade 77 - I" (#8-/898 - 3rade representing the (9 days compressive strength

in :;mm(. )or all civil engineering wor!s. Gra$e %3 & I':

(112 &1)(* Gra$e +3 & I' 122,)&1)(*

)or certain speciali+ed applications such as reinforced concrete for high risebuildings, precast buiding products, prestressed concrete for highway bridge girders,

railway sleepers, transmission line poles, water supply and waste disposal pipes,

industrial building frames and roofing elements where high strength concrete is

required.

Portlan$ -last urnace 'la/ Ceent 0P'C I': %++&1)*,

This cement can be used for all construction jobs in place of ordinary 1ortland

cement but its special properties render it highly desirable for marine structure, for

municipal wor!s such as sewers, for structures involving large masses of concrete

such as dams, retaining walls, large foundations, bridge abutments, and for structures

eposed to chemical attac! such as foundations in sulphate bearing soils.

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Portlan$ Poolana Ceent I': 1%() &1)*,

Increased impermeability, less heat of hydration, reduced al!ali - aggregate

epansion and improved resistance to aggressive chemical agencies are some of the

major benefits to be derived from the use of 11C. In mass concrete construction,

marine structures, and all other wor!s where &1C is applicable, 11C can be used

advantageously.

Ra#i$ Har$enin/ Portlan$ ceent I': (%1&1)*(

This type of cement is used when a structure is required to carry loads earlier

than what would be permitted with use of ordinary 1ortland cement, e.g. in air fields,

in emergency defense constructions and in certain precast concrete products.

4o5 Heat Portlan$ Ceent I': 12, & 1)()

This cement is suitable for mass concrete wor!s, such as dams, bridge

abutments and retaining walls, mass foundations, etc.

H"$ro#6o7ic Ceent I': (%3 &1)*(

This cement is used at place where cement has to be stored under humid damp

conditions.

'ul#6ate Resistin/ Portlan$ Ceent I': 1233 & 1)((

The use of "


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=on>t pile more than /$ bags high and arrange the bags in

header-and - stretcher fashion as close as possible.

The cement bags contain the manufactured period in terms of the

wee! of the year. This should be noted and cement manufactured

earlier shall be used earlier.

A//re/ates !or concrete

ust generally be inert, clean, dense, hard, durable, structurally sound,

capable of developing good bond with cement paste, weather resisting and be

unaffected by water.

'ource o! A//re/ate

:atural sand, gravel, pebbles.


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Ta7le 1 - ine A//re/ates 0Clause %.3

I" "ieve =esignation 1ercentage passing for

3rading 3rading 3rading 3rading

@one I @one II @one 6I @one IB

/$ mm /$$ /$$ /$$ /$$

4?' mm 8$-/$$ 8$-/$$ 8$-/$$ 8'-/$$

(.7# mm #$-8' ?'-/$$ 9'-/$$ 8'-/$$

/./9mm 7$-?$ ''-8$ ?'-/$$ 8$-/$$

#$$ micron /'-74 7'-'8 #$-?8 9$-/$$

7$$ micron '-($ 9-7$ /(-4$ /'-'$

/'$ micron $-/$ $-/$ $-/$ $-/'

'ie o! A//re/ate

Coarse a//re/ate I': 3(3&1)* defines as aggregates most of witch is retained on

4?' mm I" sieve. s si+e

should be restricted to 'mm less than the clear distance between main bars or 'mm

less than the maimum cover. 1lumes of /#$mm and above can be used in plain

concrete wor!s up to a maimum limit of ($ %. )or reinforced concrete wor!s

nominal si+e of ($mm are generally considered satisfactory.

'6a#e o! A//re/ate

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Roun$e$

2ell rounded aggregates require less water and cement for a given wor!ability of all

other shapes, as round particles have less surface area. 3enerally preferred for

pumped concrete.


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la9"

:ot recommended for concrete wor!s

*ll-in- *ggregate I" 797-/89$ defines as materials composed of fine

aggregate and coarse aggregate.

Ta7le 2 & Coarse A//re/ates Clauses %.1 an$ %.2

I"

sieve

Dmm

1ercentage passing for single-si+ed aggregate of :ominal

si+e Dmm

1ercentage passing

for graded *ggregate

of :ominal si+e Dmm

#7 4$ ($ /# /(.' /$ 4$ ($ /# /(.'

9$ /$$ - - - /$$ - - -

#7 9'-/$$ /$$ F - - - - - - -

4$ $-7$ 9'-/$$ /$$ - - - 8'-/$$ /$$ - -

($ $-' $-($ 9'/$$ /$$ - - 7$-?$ 8'-/$$ /$$ /$$

/# - - - 9'-/$$ /$$ - - - 8$-/$$ -

/(.' - - - - 9'-/$$ /$$ - - - 8$-/$$

/$ $-' $-' $-($ $-7$ - 9'-/$$ /$-7' ('-'' 7$-?$ 4$-9'

4.?' - - $-' $-' $-4' $-($ $-' $-/$ $-/$ $-/$

(.7# - - - - $-/$ - - - -

If combined aggregates are available they need not be separated into fine and

coarse aggregate, but necessary adjustments may be made in the grading by the

addition of single si+ed aggregate.

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Ta7le % & Details o! Perissi7le 4iits o! 'oli$s

Ma=iu

&rganic ($$ mg;l

Inorganic 7$$$mg;l

"ulphate Das "&4 '$$mg;l

Chloride Das Cl ($$$mg ;I for plain concrete and

/$$$ mg;l for


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good concrete. Therefore, it is necessary for us to !now what are the good rules to be

followed in each stage of manufacture of concrete for producing good quality

concrete. The various stages of manufacture of concrete are

Da atching Db iing Dc Transporting Dd 1lacing De Compacting D$ Curing Dg

)inishing

-ATCHING AND MI>ING CONCRETE ON 'ITE

Concrete consists of a mi of cement, sand, stones D coarse aggregates and

water, and to be of the right quality, the mi must be properly designed and the right

amount of each material correctly batched.

The cement, sand and coarse aggregate should be batched by weightG this

reduces the differences between one batch of concrete and the net, and ma!es things

easier for the man on the job.

4oa$in/ t6e 6o##er

The materials must be put in the hopper in the right order. 2here the hopper

turns upside down to discharge into the mier, the material batched first is last out

and, since we want the hopper to discharge cleanly, it is better if the coarse aggregate

can push the smaller, stic!ier sand and cement out in front of itG hence the coarse

aggregate usually goes into the hopper first. If the cement is fed directly into the

mier, the sand should go on top of the coarse aggregate. 6owever, if the cement is

fed into the hopper from the silo dispenser, some of it would be blown away in a high

wind if it were put on top of the sandG it is therefore usual for the cement to be

sandwiched between the coarse aggregate and the sand.

The order of loading the hopper, as described above, is the most common but

for some miers a different order might be better. *nyway, the right order will have

been wor!ed out and it is up to the batcher man and the mier driver to stic! to it.

;ater

Concrete do require water not only for hydration but also for ma!ing the fresh

concrete plastic enough to wor!, but it is very important to ensure not to add water

more than the minimum necessary.

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A$$in/ t6e 5ater

The main job of the mier driver is to add the right amount of water to each

batch. The aim is to produce concrete that is the same throughout the jobG if one batch

is dry and the net wet, the strength will be inconsistent and the variation in

wor!ability will create problems for the men placing and compacting the concrete.

Measurin/ t6e 5ater

)or any job that requires good concrete, the mier will have a water tan! and a

gauge for measuring the water. a!e sure before you start the gauge is calibrated, i.e.

that the gauge correctly corresponds to the amount of water discharged at a particular

setting and that the same amount is discharged consistently. iers get jolted and a

gauge can get out of order easily - even standing the mier on rough ground can upset

its accuracy.

To calibrate the gauge, see that the mier is level and fill the tan!G set the

gauge to a particular setting and then discharge the water from the tan! into a

container big enough to hold the epected amountG measure the amount of water in

the container to see whether it is right.


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the aggregate and water. )or rotating drum miers upto about / m 7 capacity, the

miing time needs to be / /;( to ( min. after all the materials have been fed in.

T6e irst -atc6

2ith a clean mier, some cement and sand from the first batch of concrete

will stic! to the sides and blades and, unless something is done about it, the first batch

will come out harsh and stone - short of sand and cement. To ma!e up for this loss of

cement and sand, in the first batch only, reduce the amount of coarse aggregate by

about half. =o not forget that for this first batch you will not need as much water.

3.%. T"#es o! Concrete:

Concrete is a composite product obtained by miing cement, fine aggregates,

coarse aggregates, water and admitures if necessary, to get a hardened mass.

'#ectru o! Concretes:

&ver the years, several types of concretes have been developed to suit

individual applications. They vary from the conventional plain concrete to the recent

special polymer concrete. * concise list of the well-!nown types of concretes is listed

herein indicating their characteristics in brief.

Air entraine$ concrete:

1redesigned concrete to have entrained air of '-?% to increase wor!ability

and to resist free+e-thaw cycle.

Arc6itectural concrete:

Concrete eposed as finish derived from forms or other treatments.

Coloure$ concrete:

Concrete made with white cement as binder and colour pigment (-/$ % of

weight of cement to get different colours. 0sed as finishing material.

Decorati8e concrete:

Concrete which is given a special surface finish for architectural effect.

E#o=" concrete:

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* hardened mass of epoy and aggregate.

E=#ansi8e concrete:

Concrete in which drying shrin!age is fully compensated for.

erro&ceent:

)ine cement mortar combined with high degree of distributed thin

reinforcement mesh. ade in very thin sections. Ideal as replacement to timber, steel

etc. 0sed as containers, boat etc..

i7re rein!orce$ concrete:

Concrete in which fibres of glass, steel or other materials are introduced to

improve certain properties.

oae$ 0or aerate$ concrete:

Hightweight concrete in which the low density is obtained by the chemical

reaction of an admiture with the cement, resulting in the formation of a cellular

structure with bubbles of gas.

Ga#&/ra$e$ concrete:

Concrete mi designed with omission of undesirable intermediate grades of

aggregates. Improves strength better.

Gunite$ concrete 0or s6otcrete:

Concrete made by spraying under pressure a miture of cement, aggregates

and water on to a surface.

Granolit6ic concrete:

Concrete made with specially selected hard aggregates and used as wearing

course of floors.

Hi/6 stren/t6 concrete:

Concrete giving strength above #$ :;mm( and considered feasible upto /'$

:;mm(with introduction of ultra fines li!e condensed silica fume, and by the use of

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super plastici+ers to limit water cement ratio in the range of $.(4-$.7'

Hea8"&5ei/6t concrete:

Concrete made with specially selected heavy aggregates to give a density

eceeding 7$$$ !g;m .

In&situ concrete:

Concrete, which whilst in its plastic state, is deposited in the location where it

is required to form apart of the structure.

4ean concrete:


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"tructural light weight aggregate concrete which is prestressed.

Pol"er concrete:

Concrete which is impregnated with apolymer compound or has polymer as

binder, to improve certain properties.

Pu#e$ concrete:

Concrete which is transported from the mier or delivery point of ready mied

concrete to the placing position by being pumped through a pipeline.

Rea$"&i=e$ concrete:

Concrete made at a place away from the construction site and conveyed in

special vehicles, delivered ready to use.

Re!ractor" concrete:

Concrete made with insulating Dli!e bric! aggregates and high alumina

cement for use in shielding or damping of heat.

Rein!orce$ concrete:

Concrete in which bars or fabric, usually of steel, are embedded in such a

manner that the two materials act together under load.

Rolle$concrete:

Concrete having a high aggregate cement ratio, which is compacted by a

road-roller and used as abase for road construction.

'a5 $ust concrete:

Concrete prepared by miing 1ortland cement with sawdust in specified

proportions in addition to concrete.

'6oc9 concrete:

Concrete compacted by dropping fresh concrete in a mould through a

predetermined height.

'#un concrete: Concrete compacted by centrifugal action.

'tructural li/6t 5ei/6t a//re/ate concrete:

Concrete having a density not eceeding /,9$$ !g;m7and made from

artificially produced aggregates, capable of developing a compressive strength

ranging from ('$-'$$!g;cm(.

'ul#6ur i#re/nate$ concrete:

Concretes impregnated with molten sulphur to give high strength and acid

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resistance- used in small components for outdoor

Terrao concrete:

Concrete made with marble aggregates and used as a surface finish on floors

and walls.

Treie concrete:

Concrete placed under water through a vertical steel pipe. *voiding contact

with water before placement.

?accu concrete:

Concrete in which ecess water required ma!ing the mi wor!able is etracted

by vacuum process before the cement has set.

?i7rate$ concrete:

Concrete compacted by vibratory effect, introduced either internally or

eternally while concrete is plastic.

CONCRETE TE'TING

I#ortance o! testin/:

=epending upon the test results of test cubes, strength in the actual structure

can be compared. If the strengths are not as per the I" requirements, then

modifications can be made in the mi proportions and again testing is carried out.

Consistency in test results would give confidence in concrete ma!ing and its placing.

This confidence which can be gained through testing is very important 6ence,

TE"TI:3 is very essential. Testing is epected to control the quality and finally lead

to 0*HITJ *""0


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cement shall be made up of a small portion ta!en from each of a number of bags on

the site. Test samples of aggregate shall be ta!en from larger lots by quartering.

Pre#aration o! Materials:

*ll materials shall be brought to room temperature, preferably (?5CK75C

before commencing the tests.

The cement samples, on arrival at the laboratory, shall be thoroughly mied

dry either by hand or in a suitable mier in such a manner as to ensure the greatest

possible blending and uniformity in the material, care being ta!en to avoid the

intrusion of foreign matter. The cement shall then be stored in a dry place, preferably

in air-tight metal container.

"amples of aggregate for each batch of concrete shall be of the desired

grading and shall be in an air-dried condition. In general, the aggregate shall be

separated into fine and coarse fractions and recombined for each concrete batch in

such a manner as to produce the desired grading. I" sieve 49$ shall be normally used

for separation of the fine and coarse fractions, but where special grading are being

investigated, both fine and coarse fractions shall be further separated into different

si+es.

Pro#ortionin/:

The proportions of the materials, including water in concrete mies used for

determining the suitability of the materials available, shall be similar in all respects to

those to be employed in the wor!. 2here the proportions of the ingredients of the

concrete as used on the site are to be specified by volume, they shall be calculated

from the proportions by weight used in the test cubes and the unit weights of the

materials.

;ei/6in/:

The quantities of cement, each si+e of aggregates and water for each batch

shall be determined by weight, to an accuracy of $./% of the total weight of the

batch.

Mi=in/ o! concrete:

In machine miing, when the miing drum is charged by a power loader, all

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the miing water shall be introduced into the drum before the solid materials, the s!ip

shall be loaded with about one-half of the coarse aggregate, then with the fine

aggregate, then with the cement and finally with the remaining aggregate on top. The

period of miing shall be not less than ( minutes after all the materials in the drum

and shall be continued till the resulting concrete is uniform in appearance.

'ie o! s#eciens:

Test specimens cubical in shape shall be I'cm/'cm/'cm.

Moul$:

The mould shall be of metal, preferably steel or cast iron. It shall be

constructed in such a manner as to facilitate the removal of the moulded specimen

without damage, and shall be so machined that, when it is assembled ready for use,

the dimensions and internal faces shall be accurate. In assembling the mould for use,

the inner faces shall be oiled neatly.

Ta#in/ ro$:

The tamping bar shall be a steel bar /#mm in diameter, $.#m long and bullet

pointed at the lower end.

Co#actin/:

The test specimens shall be made as soon as practicable after miingG the

concrete shall be filled into mould in layers approimately 'cm deep. Each iayer shall

be compacted ether by hand or by vibration. (' blows are given to concrete to each

layer while hand compaction is done. 2hen compacting by vibration, each layer shall

be vibrated by means of an electric hammer or vibrator or by means of suitable

vibrating table until the specified condition is attained. during

The test specimens shall be stored in aplace free from vibration, in moist air

of at least 8$% relative humidity and at temperature (?5C K (5C for (4 hoursK A4

hour from the time of addition of water to the dry ingredients. *fter this period, the

specimen shall be mar!ed and removed from the moulds and, unless required for test

within (4 hours, immediately submerged in clean, fresh water and !ept there until

ta!en out just prior to test. The water or solution in which the specimens are

submerged shall be renewed every ? day and shall be maintained at a temperature of

(?5C K (5C. The specimen shall not be allowed to become dry at any time until they

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have been tested.

2. TE'T OR COMPRE''I?E 'TRENGTH O CONCRETE 'PECIMEN 0As

#er I' +1,&1)+)B clause +

A##aratus:

Testing machine the testing machine may be of any reliable type of sufficient

capacity for the tests and capable of applying the load at the rate /4$ !g;sq cm ;min.

The permissible error shall be not greater than K (% of the maimum load.

A/e at test:

Test shall be made at recogni+ed ages of the test specimens, the most usual

being ? and (9 days. :umber of specimen atleast 7 specimens, shall be made for

testing at each selected age.

Proce$ure:

"pecimens stored in water shall be tested immediately on removal from the

water. "urface water and grit shall be wiped off the specimen and any projecting fins

removed. "pecimen when received dry shall be !ept in water for (4 hours before they

are ta!en for testing.

Placin/ t6e s#ecien in t6e testin/ ac6ine:

The bearing surfaces of the testing machine shall be wiped clean and any

loose sand or other material removed from the surface of the specimen which is to be

in contact with the compression plates. In the case of cubes, the specimen shall be

placed in the machine in such a manner that the load shall be applied to opposite

sides of the cube as cast, that is not to be top and bottom. The ais of specimen shall

be carefully aligned with the center of thrust of seated plates. :o pac!ing shall be

used between the face of the test specimen and the steel plate of testing machine. The

movable portion shall be rotated by hand so that uniform seating may be obtained.

The load shall be applied continuously at a rate of /4$!g ;sq cm. ;min until the

resistance of specimen to the increasing load brea!s down and no greater load can be

sustained. The maimum load applied to the specimen shall then be recorded and the

appearance to the concrete and any unusual features in the type of failure shall be

noted.

Calculation:

The measured compressive strength of the specimen shall be calculated by

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dividing the maimum load applied to the specimen during the test by the cross

sectional area, calculated from the mean dimensions of the section and shall be

epressed in !g;sqcm. *verage of three valued shall be ta!en as the representative of

the batch provided the individual variation is not more than K/'% of average.

&therwise repeat test shall be made.

CHAPTER: 3

CONCRETE MI> DE'IGN

General:

i design can be defined as the process of selecting suitable ingredients of

concrete and determining their relative proportions with the object of producing

concrete of certain minimum strength and durability as economically as possible. The

design of concrete mi is not a simple tas! on account of the widely varying

properties of the constituent materials, the conditions that prevail at the site of wor!,

in particular the eposure condition, and the conditions that are demanded for a

particular wor! for which the mi is designed.

The purpose of mi designing is two-fold. The first object is to achieve the

stipulated minimum strength and durability. The second object is to ma!e the

concrete in the most economical manner. Cost wise all concretes depend primarily on

two factorsG namely cost of material and cost of labour. Habour cost, by way of

formwor!s, batching, miing, transporting, and curing is nearly same for good

concrete and bad concrete. Therefore attention is mainly directed to the cost of

materials. "ince the cost of cement is many times more than the cost of other

ingredients, attention is mainly directed to the use of as little as possible consistent

with strength and durability.

Conce#t o! i= $esi/n:

The relationship between aggregate and paste is necessary to study as the

aggregate and pastes are the essential ingredients of concrete. 2or!ability $/ the

mass is provided by the lubricating effect of the paste and is influenced by the

amount and. dilution of paste. The strength of concrete is limited by the strength of

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d. "urface area method

e. Indian


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to ensure a certain quality at a specified ris!. Thus the method provides a scientific

basis of acceptance which is not only realistic but also restrictive as required by the

design requirements for the concrete construction. The compressive strength test

cubes from random sampling of a mi, ehibit variations, which are inherent in the

various operations involved in the ma!ing and testing of concrete. If a number of

cube test results are plotted on histogram, the results are said to follow a normal

distribution curve if they are equally spaced about the mean value and if the largest

number of the cubes have a strength closer to the mean value, and very few number

of results with much greater or less value than the mean value. 6owever, some

divergence from the smooth curve can be epected, particularly if the number of

results available is relatively small.

"ince for the I" Code recommended method is used for the mi design of

concretes in this project wor!, the detailed step by step procedure of I" Code method

is eplained.

In$ian 'tan$ar$ Co$e recoen$e$ Met6o$ I' 12,2&1)(2

The Indian "tandard Code I" /$(#(-/89( presents guidelines for mi design.

The basic assumption made in mi design is that the compressible strength of

wor!able concrete is by and large governed by the water;cement ratio. In this method

of mi design the water content and proportion of fine aggregate corresponding to a

maimum si+e of aggregate are first determined for reference values of wor!ability,

water;cement ratio and grading of fine aggregate. The water content and the

proportion of fine aggregate are then adjusted for any difference in wor!ability,

water;cement ratio and grading of fine aggregate in any particular case from the

reference values. The batch weight of materials per unit volume of concrete is finally

calculated by the absolute volume method.

-asic Date Reuire$.

a) Characteristic compressive strength of concrete at (9 days.

b) inimum si+e of aggregate to be used, its type, grading pattern.

a) =egree of wor!ability in terms of slump, having regard to type of wor!

and mode of completion.

b) =egree of control epected to be eercised in terms of the coefficient of

variation.

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c) Epected tolerance level.

d) Compressive strength of cement at ?days.

e) "pecific gravity of cement, fine aggregate and coarse aggregate.

f) 1ercentage water absorption or free moisture in the aggregate.

g) "ieve analysis and ).. of sand.

h) "tandard deviation Ds of compressive strength of concrete which is as below.

Ta7le NO. 1

3rade of "tandard deviation )or different degree of control :;"qmm

concrete Bery good 3ood )air

/' ( (.7 7.7

($ (.' 7.' 4.'

(' 7.# 4.# r+iT

TA-4E 2 DEGREE O PECTED UNDER

DIERENT 'ITE CONDITION'

DClause #.4

DEGREE O CONDITION' O

CONTRO4 PRODUCTION

Bery 3ood

3ood

)air

R.I.T. Sakharale 26


27/60


)resh cement from single source and

regular tests, weigh batching of all

materials, aggregates supplied in single

si+es, control of aggregate grading and

moisture content, control of water

added, frequent supervision, regular

wor!ability and strength tests, field

laboratory facilities.

Carefully stored cement and periodic

tests, weigh batching of all materials,

controlled water, graded aggregate

supplied, occasional grading and

moisture tests, periodic chec! of

wor!ability and strength, intermittent

supervision, eperienced wor!ers.

1roper storage of cement, volume

batching of all aggregates allowing for

bul!ing of sand, weigh batching of

cement, water content controlled by

inspection of mi, occasional

supervision and tests.

R.I.T. Sakharale 27


28/60

'te#s in Mi= Desi/n

1. Calculation o! tar/et stren/t6 o! i= $esi/n -

The concrete mi has to be designed for a somewhat higher average

compressive strength Dfc!. The margin over the characteristic strength depend upon

the quality control and the accepted proportion of result of strength tests below the

characteristics strength Dfc!, given by relation.

f c! L f c! M t "

2here,

fc!L target average compressive strength at (9 days

fc!Lcharacteristic compressive strengt at (9 days

s L standard deviation Table :o.7 and

t L a statistics, depending upon the accepted of low results and the number of

tests which is given in following Table :$.4

Ta7le 3 'UGGE'TED ?A4UE' O 'TANDARD DE?IATION

0Clause ,.%

Gra$e O!

Concrete

'tan$ar$ De8iation or Di!!erent

$e/ree o! control 0N2

01

M1

M 1+

M 2

M 2+

M 3

M 3+

M %

M %+

M +

M ++

M ,

?er" Goo$ Goo$ air

02

2.

2.+

3.,

%.3

+.

+.3

+.,

,.

,.%

,.*

,.(

03

2.3

3.+

%.,

+.3

,.

,.3

,.,

*.

*.%

*.*

*.(

0%

3.3

%.+

+.,

,.3

*.

*.3

*.,

(.

(.%

(.*

(.(


29/60

Ta7le No. %

*ccepted proportions of low results t

/ in ' $.94in /$ /.(9

/ in /' /.'$

/ in ($ /.#'

Note: *s per I" 4'#-/8?9 the characteristics strength is defined as that value below

which not more than five percent D/ in ($ results are epected to fall in which case

the above equation is

fc! L fc! M /.#' s

2. Nnowing the seven day compressive strength of cement proposed to

be used and (9 days average design strength of concrete, find the w;c

ratio from figure / and ( respectively. The free w;c; ratio selected as

above should be chec!ed against the limiting water cement ratio for

the requirement of durability and the lower value of the two values

adopted.

3. Estimation of air content *pproimate amount of entrapped air to be

epected in normal concrete given below.

%. Ta7le No. +

:ominal maimum si+e of

aggregate Dmm

Entrapped air as % of volume of

concrete

/$ 7

($ (

4$ /

'. "election of water content and fine to total aggregate ratio for the

desired wor!ability, the quantity of miing water per unit volume of

concrete and the ratio of fine aggregate to the total aggregate by


30/60


31/60

6. )or other condition of wor!ability, w;c ratio and for rounded aggregates,

certain adjustment in the quantity of miing water and fine to total

aggregate ratio are to be made by using following table no.9.

*.Ta7le No.(

C6an/e in con$ition

sti#ulate$ !or ta7le 12

A$Fustent reuire$ in

;ater content in total a//re/ate

)or sand confirming to +one il,

I, III, IB of I" 797-/8?$

$ M /.'% for +one I

-/.'% for +one III

-7.$% for +one IB

Increase or decrease in the value

of c.f. by $./

K7% $

Each $.$' increase or

decrease in free w;c ratio

$ K/%

)or rounded aggregates -/' !g;cum -?%

O specification for coarse and fine aggregate from natural source for concrete

9. Calculation of cement content !nowing the w;c ratio and water

content Dw the cement content Dc is determined.

9. Calculation of cement content The total aggregate content per unit

volume of concrete is calculated from the equation -

2here,

B L P2 M C;"c M fa ; 1."faQ /;/$$$B L P2 M C;"c M ca ; D/-1 "faQ /;/$$$

2here,

B L absolute volume of fresh concrete.

L 3ross volume - volume of entrapped air

2L mass of water D!g ; cum of concrete

C L mass of cement D!g ; cum of concrete

1 L ratio of fine aggregate to total aggregate by absolute volume. "c, "fa


32/60

R "ca L specific gravity of cement, fine agg., R coarse agg. fa R ca L total

mass of fine aggregate R coarse aggregate !g; cum of concrete respectively.

/$. Nnowing the w;c ratio, cement content, total aggregate content and %

sand content the mi proportion can be arrived at.

//. This mi proportion must be adjusted, if the aggregate is moist.


33/60

CHAPTER: %

E>PERIMENTA4 PROGRAMME

The eperimental wor! consists in finding the mi ratio for the concrete

prepared by volume batching Dusing farma for chec!ing its compressive strength

with the compressive strength of concrete prepared by design mi.

It has been seen that, mostly local contractors are adopting farma mi Dvolume

batching for manufacturing the concrete. The materials for ma!ing this concrete are

also obtained from the nearby available sources only. )or construction of buildings In

Islampur city and nearby areas, the sand Dfine aggregate generally is brought from

@ris6na river from the sources located near villages ahe, Nharatwadi and

al!hed. *ll these sources of sand are located at short distances from Islampur city

and hence are preferred by local contractors. 6owever, the current practice in ma!ing

concrete in almost ail constructions is by volume batching i.e. either by using farma

Dgauge bo of $.$7'cum or even by using pots of varying si+es. *lso there is wide

variation in mi ratios for ma!ing concrete. The concrete thus manufactured is simply

judged for its wor!ability and also for strength based on the colour of concrete and by

eperience in concreting. 3enerally wor!ability, strength and other properties of

concrete are not chec!ed by any means at the site. This fact has necessitated searching

for a specific mi ratio by using materials of concrete from various sources which will

give desired strength of concrete.

In the present eperimental wor! one of the important ingredient of concrete

namely, >sand> is considered for ma!ing the concrete by varying its quantity

Dproportion to study the effect on the compressive strength of concrete. The sand

from three different sources of Ri8er @ris6na+was collected for ma!ing concrete.

The details of these ingredients of concrete are given as below S

Ceent:&

'7 grade cement with a brand name of -irla '6a9ti satisfying all I" a

requirement was used in ma!ing the concrete specimens.


34/60

ine a//re/ates 0san$:&

"and free of dust, organic matter etc from three different sources was

collected. The "ieve analysis for the sand obtained from all the three sources was

done and the results are shown in the table.

Coarse a//re/ates:&

The coarse aggregates are also brought from the nearby sources for

construction of buildings. The most common source of coarse aggregates Dcrushed

particle stones is the hilloc! near village @aeri along the NH% . route. The

aggregates used in concrete are from this source and are satisfying the desired

qualities for ma!ing the concrete.

;ater: - Clean, potable water was used in ma!ing the concrete. Mi=

Desi/n o! concrete:&

1 Mi= Desi/n o! concrete 7" I' Co$e et6o$

The mi design for ($ grade concrete was carried out using I" Code method

for arriving at the mi ratios for three different sand samples. The mi ratios

determined for the ($ grade concrete are 1:1.,2:3.12 1:1.+2:3.1, and 1:1.+2:3.1,

using sand from "ources ane, Nharatwadi and al!hed respectively. Concrete cubes

of /'cm side were cast using various mi ratios as obtained in the Mi= Desi/n DI"

Code method process for the three different sand samples and were cured in for (9

days under water and then tested for their compressive strength.

The actual mi design of ($ 3rade concrete as per I" Code method is

carried out for three different sands is presented below.

0I Mi= Desi/n !or M2 Gra$e Concrete 7" usin/ I' et6o$'ource o! 'an$ & @6arat5a$i a Desi/n 'ti#ulations

Characteristic compressive strength required in the field at (9 days -($

:;sqmm.

aimum si+e of aggregate - ($mm Dangular

=egree of wor!ability - $.8$ Dcompacting factor

=egree of quality control - 3ood

Type of eposure - ild


35/60

7 -asic $ata !or aterials Ta7le no.). -asic $ata !or concrete i= $esi/n !ro

8arious tests on

in/re$ients.

/ rand of Cement irla sha!tiType of cement &pe

7 "pecific 3ravity of cement 7./'

4 =egree of quality control 3ood

' Type of eposure ild

# Type of fine aggregate :atural sand

? "pecific gravity of fine aggregate (.#'

9 2ater absorption of fine aggregate /.'%

8 aimum si+e of aggregate ($mm

/$ )ine aggregate in total aggregate 4$ %

// "pecific gravity of coarse aggregates (.?'

/( 2ater absorption of coarse aggregate /.' %

/7 2ater absorption of coarse aggregate / %

/4 Coarse aggregate D($mm in total aggregate

c Tar/et mean stren/t6 of concrete for a tolerance factor of /.#' and using

table no.98 D6and boo! of concrete mies page no. //7 the target mean

strength for the specified characteristic cube strength is

fc! L fc! M ts

fc! L ($ 1a

t L 4.# Dtable no.7

s L/.#' Dtable no.4

L ($ M 4.# /.#'

L (?.'$ :;sq mm


36/60

$ 'election o! 5ater&ceent ratio

The w;c ratio required for the target mean strength of (?.#$ :;sq mm

is $.'$. This is lower than the maimum value of $.#' prescribed for mild

eposure Dtable no.(

e 'election o! 5ater an$ san$ content -

Nominal maimum si+e aggregate and sand confirming to grading

+one II, water cement per cubic meter of concrete is equal to /9# !g and sand

content as percentage of total aggregate by absolute value is equal to 7'%. )or

change in values in water - cement ratio, compacting factor and sand

belonging to +one II the following adjustment is required.

Ta7le no.1.Test Results o! 'an$ &'ource o! san$&@6arat5a$i

2eight of sample -'$$gm

I.". "ieve 2t. retained

Dgm

Cumulative

wt retained

Cumulative %

wt retained

Cumulative %

wt passing

/$mm $ $ $ /$$

4.?#mm (8 (8 '.9 84.(

(.7#mm (4 '7 /$.# 94.(

/./9mm 99 /4/ -(9.( ?8.4

#$$ /'# (8? '8.4 #/.9$

7$$ /49 44' 98 7$.#

/'$ '$ 48' 88 /

Hower than

/'$

' '$$ - -

Note: The sand from Nharatwadi undergoes @one II


37/60

C6an/e in con$ition a$Fustent reuire$ in

Dsee table 9

2ater content % percentage sand

in total aggregate

i )or decrease in w;c ratio $ - (.$

y D$.#$-$.'$ i.e. $./

ii )or increase in compacting 7 $

factor i.e. D$.8-$.9 i.e. $./

iii )or sand confirming +one II $ $

Table 4 of I" 797-/8?$ ---------- ---------

M 7 - (.$ %

Therefore, required sand content as percentage of total aggregate by absolute

volume L7' -(.$ L77 %


38/60

$.'$ / /.'( 7.($

h *ctual quantities required for the mi per bag of cement. The mi is $.'

//.'( 7.($ for '$ !g of cement the quantity of materials required is as

below.

1) cement L '$ !g

2) sand L ?# !g

1) aggregate L /#$ !g

D)raction I L 8# !g

D)raction II L #4 !g

i 2ater

1. 2ater-cement ratio of $.', water L ('.$ litre

2. Etra water to be added for absorption in case of coarse

aggregate at /% by massL DM/.#

3. water to be deducted for free moisture present in sand at (% by

mass L -/.'(

4. *ctual quantity of water to be added L (' M/.#$ - /.'(L ('.$9

liter

5. actual quantity of sand required after allowing for mass of free

moisture L ?# M/.'( L ??.'( !g

6. *ctual quantity of corresponding aggregate required

a) )raction I L 8#-$.8# L 8'.$4 !g

b) )raction II L #4 -$.#4 L #7.7# !g

*ctual quantity required - for ' !g 2ater L(.' litre )ine aggregates L 9./$8 !g Coarse

aggregates D($mm L 8.79' !g D/(mm

L#.('8 !g


39/60

0II Mi= Desi/n !or M2 Gra$e concrete 7" usin/ I' et6o$ 'ource o! 'an$&

Mal96e$

Da =esign "tipulations

Characteristic compressive strength required in the field at (9 days -($

:;sqmm.

aimum si+e of aggregate - ($mm Dangular

=egree of wor!ability - $.8$ Dcompacting factor

=egree of quality control - 3ood

Type of eposure - ild

Db asic data for materials

Ta7le no.11.-asic $ata !or concrete i= $esi/n !ro 8arious tests on

in/re$ients.

/ rand of Cement irla sha!ti

( Type of cement &pe








/$ )ine aggregate in total aggregate 4$%


/( 2ater absorption of coarse aggregate /.'%

/7 2ater absorption of coarse aggregate /%


Dc Target mean strength of concrete for a tolerance factor of /.#' and using

table no.98 D6and boo! of concrete mies page no. //7 the target mean strength for

the specified characteristic cube strength is

fc! L fc! M ts


40/60

fc! L ($ 1a

tL4.# Dtable no.4

sL/.#' Dtable no.7

L ($ M 4.# /.#' L (?.'$ :;sq mm

0$ 'election o! 5ater & ceent ratio

The w;c ratio required for the target mean strength of (?.#$ :;sq mm is

$.'$. This is lower than the maimum value of $.#' prescribed for mild

eposure DTable (

?. 'election o! 5ater an$ san$ content -nominal maimum si+e aggregate and sand

confirming to grading +one II, water cement per cubic meter of concrete is equal

to /9# !g and sand content as percentage of total aggregate by absolute value is

equal to 7'%. )or change in values in water - cement ratio, compacting factor

and sand belonging to +one II the following adjustment is required.

Table no.12.Test Results o! 'an$ & 'ource o! san$ &Mall96e$

;ei/6t o! sa#le &+/

I."."ieve 2t. retained

Dgm

Cumulative

wt retained

Cumulative %

wt retained

Cumulative %

wt passing

/$mm $ $ $ /$$

4.?#mm (/ (/ 4.( 8'.9

(.7#mm 7$ '/ /$.( 98.9

/./9mm 88 /'$ 7$.$ ?$.$#$$ /## 7/# #7.( 7#.9

7$$ /49 4#4 8(.9 ?.(

/'$ 7( 48# 88.( $.9

Hower than

/'$

4 '$$ - -

:ote The sand from Nharatwadi undergoes @one II


41/60

C6an/e in con$ition a$Fustent reuire$ in

D"ee table 9

2ater content % percentage sand

in total aggregate

iv )or decrease in w;c ratio $ - (.$

by D$.#$-$.'$ i.e. $./

v )or increase in compacting 7 $

factor i.e. D$.8-$.9 i.e. $./

vi )or sand confirming +one II & $

Table 4 of I" 797-/8?$ ------------- ------------------

M 7 - (.$ %


volume L7' -(.$ L77 %


42/60


43/60

0II Mi= Desi/n !or M2 Gra$e concrete 7" usin/ !' et6o$

'ource & -a6e 'an$

I. Desi/n 'ti#ulations

(1) Characteristic compressive strength required in the field at (9 days

($ :;sqmm.

(2) aimum si+e of aggregate - ($mm Dangular

(3) =egree of wor!ability - $.8$ Dcompacting factor

(4) =egree of quality control - 3ood

(5) Type of eposure - ild

II . -asic $ata !or aterials

Ta7le no.1%. -asic $ata !or concrete i= $esi/n !ro 8arious tests on

ingredients.

/ rand of Cement irla sha!ti

( Type of cement &pe








/$ )ine aggregate in total aggregate 4$%


/( 2ater absorption of coarse aggregate /.'%

/7 2ater absorption of coarse aggregate /%


II. Tar/et ean stren/t6 of concrete for a tolerance factor of /.#' and using table


44/60

no.98 D6and boo! of concrete mies page no. //7 the target mean strength for the

specified characteristic cube strength is

fc! L fc! M tX"

fc! L ($ 1a

t L4.# Dtable no.4

s L/.#' Dtable no.7

L ($ M 4.# /.#' L (?.'$ :;sq mm

I?. 'election o! 5ater & ceent ratio

The w;c ratio required for the target mean strength of (?.#$ :;sq mm is $.'$.

This is lower than the maimum value of $.#' prescribed for mild eposure DTable

(

?.'election o! 5ater an$ san$ content -nominal maimum si+e of aggregate and

sand confirming to grading +one II, water content per cubic metre of concrete is

equal to /9#!g and sand content as percentage of total aggregate by absolute volume

is equal to 7'%

)or change in values in water-cement ratio compacting factor and sand belonging

to +one I following adjustment is required.

Ta7le no.1,. 'ie8e anal"sis o! !ine a//re/ates &source -a6e

I' 'ie8e ;t. retaine$

0/

Cuulati8e 5t

retaine$ 0/

Cuulati8e 5t

retaine$ 0/

Cuulati8e

#assin/

/$mm $ $ $ /$$

4.?'mm '# '# //.( 99.9

(.7#mm 47 88 /8.9 9$.(

/./9mm /(( ((/ 44.( ''.9

#$$ /## 79? ??.4 ((.#


45/60

7$$ 8$ 4?? 8'.4 4.#$

/'$ u (/ 489 88.#$ $.4

Hower than .

'$

( '$$

C6an/e in con$ition A$Fustent reuire$ in

2ater content % 1ercentage sand

in total aggregate

a) )or decrease in w;c ratio $ - (.$

by D$.#$-$.'$ i.e. $./

b) )or increase in compacting 7 $

factor i.e. D$.8-$.9 i.e. $./

c) )or sand confirming +one II $ M/.'

Table 4 of I" 797-/8?$ ---------- ---------

M 7 -$.'$%


volume L7' -$.'$ L74.'$ %

)or '!g of cement

2ater L '.$/# lit

"and L?.?'(!g

*ggregate ($mmL8.'$4!g

*ggregate /(mm L #.77 !g


46/60


47/60

were cured them for (9 days under water and then tested for the . compressive

strength.

2 Concrete 7" Usin/ ara Mi= 0-" ?olue -atc6in/

ara is a site word for a gauge bo used for volume batching i.e. for

measuring the quantities of concrete ingredients by volumetric method. The si+e of

the bo is 7?'mm7$$mm7$$mm which accommodates the quantity of one bag of

cement of '$ !g. )or small construction wor!s generally volume batching is resorted

in concrete ma!ing and also there is no uniformity in adopting a specific mi ratio.

i ratios li!e 1:2:3B 1:2:%B 1:3:3B 1:3:% etc are generally adopted when farma is

used. 6owever, if 3hamelas Dpots are used for concrete ma!ing then the mi ratios

adopted may be 1:1:12 i.e. for / bag of cement /$ 3hamelas of sand and /(

3hamelas of coarse aggregate. &ther mi ratios adopted being 1:1:11B1:11:13 and

soon.

Therefore, in order to achieve the compressive strength of ($ grade

concrete, as per i =esign method, several trial mi ratios were chosen. The

concrete cubes using these mi ratios were cast Di.e. by volume batching and are

cured and tested in the same manner as that of the concrete cubes by i =esign

ethod Di.e. I" Code method.

=uring miing of concrete in farma mi method, it was observed that the w;c

ratio was required to be varied in order to achieve the desired wor!ability. Barious

w;c ratios adopted were $.'$, $.#( and $.'# for the concrete mi prepared with sand

from source ahe, for mi ratios of /(7, /77 and /74 respectively.

0II Mi= Desi/n 7" 8olue 7atc6in/ 0Usin/ !ara /au/e 7o=

Conversion of gauge bo from volume to weight -

1. 2eight of one bo of cement L '$ !g

2. 2eight of one bo of sand L #4.?$( !g

3. 2eight of one bo of aggregate L ''.'4# !g

0A or @6arat5a$i san$


48/60

1. 1roportion-/77

2. Cement -'$ !g -7!g

3. "and -/84./$#!g -//.#4# !g

4. *ggregate -(((./94!g -8.89 !g

5. 2;C ratio-D/.?';7 L$.'9

a) 1roportion -/74

b) Cement - '$ !g - 7!g

c) "and -/84./$#!g -/'.'( !g

d) *ggregate-(((./94!g -/?.??!g

e) 2;C ratio - D(.?';4 L$.#9

D( Pro#ortion 1:2:3

ii. Cement -'$ !g -7!g

iii. "and -/(8.4$#!g -/$.7' !g

iv. *ggregate - /##.#79!g -/7.77 !g

v. 2;C ratio - D(.$;4 L $.'$

0- or Mal96e$ san$

J Pro#ortion -1:3:3

Cement - '$ !g - 4!g

"and -/84./$#!g -/'.'( !g *ggregate-/##.#7!g -/7.7((!g 2;C

ratio - D(.' ;4 L$.#('

Y Pro#ortion &1:3:%

Cement - '$ !g - 7!g"and -/84./$#!g -/'.'( !g

*ggregate -(((./94!g -/?.?? !g

2;C ratio - D(.?';4 L$.#9

Pro#ortion 1:2:3


"and -/(8.4$#!g -/$.7' !g

*ggregate -/##.#79!g -/7.77 !g


49/60

2;C ratio - D(.$;4 L$.'$

DC or -a6e san$

a. Pro#ortion -1:3:3


"and . -/84./$#!g -/'.'( !g

*ggregate- /##.#7!g - /7.7((!g

2;C ratio - D(.';4 L$.#('

7. Pro#ortion &1:3:%


"and -/84./$#!g -/'.'( !g

*ggregate -(((./94!g -/?.?? !g

2;C ratio - D(.(' % L$.'#

c. Pro#ortion 1:2:3


"and -/(8.4$#!g -/$.7' !g

*ggregate - /##.#79!g -/7.77 !g

2;C ratio - D(.$;4 L$.'$

Rest Pro/ra:&

*II the concrete cubes were tested for their compressive strength under the

compressive testing machine D/$$tonnes capacity as per the standard procedure laid

down in handboo! of concrete mies. The crushing load was noted at the initiation of

first crac! on the concrete face for every cube specimens. The details of the test

results are tabulated in the table no /#.

Table no. /# "ource of sand - Nharatwadi


50/60

"r

:o.

:o of

days

"pecimen

no

Hoad at

failure

Cross

sectional

area of

bloc!

Target

compressive

strength MPa

*verage

compressive

strength 1a

/ (9 N/ 9/.' (('$$ 79.7?

7?.(/( (9 N( 9$ (('$$ 7'.7(

7 (9 N7 97.?' (('$$ 7?.87

Ta7le no.1*. 'ource o! san$ & Mal96e$

'I.

No.

:o of

days

"pecimen

no

Hoad at

failure

DN:

Cross

sectional

area

Target

compressive

strength 1a

*verage

compressive

strength 1a

/ (9 / 9($$$ (('$$ 7'.'' 7'.4$

( (9 ( ??$$ (('$$ 7'.//

7 (9 7 ?8$$$ (('$$ 7'.''

Ta7le. 'ource o! san$ & -ane

"I.

:o.

:o of

days

"pecimen

no

Hoad at

failureDN:

Cross

sectionalarea

Target

compressivestrength 1a

*verage

compressivestrength 1a

/ (9 / 98$$ (('$$ 79.9$ 78.(4

( (9 ( 8$$$ (('$$ 78.(4

7 (9 7 8/$$ (('$$ 78.#?

Ta7le no.1(. Test Results o! @6arat5a$i 'an$ & usin/ !ara

(3) Curing period -(9 days

(4) "i+e of cube -/'$mm/'$mm/'$mm

(5) C;" area -(('$$ sqmm >


51/60

"I

:o.

"p.

No

i

1roportion

Hoad at

failure

Target comp

strength 1a

*verage comp

strength 1a

/ @1 /77 #'$$ (9.99

(8.8(( N/ /77 #'$$ (9.99

7 N/ /77 ?($$ 7(.$$

/ N( /74 '4$$ (4.$$

(7.9'( N( /74 '($$ (7.//

7 N( /74 ''$$ (4.44

/ N7 /(7 ?'$$ 77.77

77./9( N7 /(7 ?'$$ 77.77

7 N7 /(7 ?4$$ 7(.99

Ta7le no.1). Test Results o! Mal96e$ 'an$

'I

No.

T"#e o!

s#ecien

Mi= Ratio 4oa$ at

!ailure 0@N

Tar/et co#

stren/t6B MPa

A8/ co#

stren/t6B MPa

/ / /77 ?($$ 7(.$$

7$.9/( / /77 #?$$ (8.??

7 / /77 #8$$ 7$.##

/ ( /74 #4$$ (9.44

(9.99( ( /74 #8$$ 7$.#?

7 ( /74 #($$ (?.''

I 7 /(7 9#$$ 79.((

4/.49( 7 /(7 8'$$ 4(.((

7 7 /(7 88$$ 44.$$


52/60

Ta7le no. 2. Test Results o! -a6e 'an$

'o

No.

'#ecien

no

Mi= Ratio 4oa$ at

!ailure

Tar/et co#

stren/t6B MPa

A8/ co#

stren/t6B MPa

/ -1 /77 '#$$ (4.99

(4./4( -1 /77 '($$ (7.//

7 -1 /77 ''$$ (4.44

/ -2 /74 ?'$$ 77.77

77./9( -2 /74 ?7$$ 7(.44

7 ( /74 ?#$$ 77.??

/ 7 /(7 99$$ 78.//

78.9'( 7 /(7 87$$ 4/.77

7 7 /(7 99$$ 78.//


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CHAPTER: +

CO'T ANA4'I'

The cost analysis of concretes prepared by both methods of batching has been

wor!ed out considering the mar!et prices of materials with ="< labours charges.

The details of the calculations for the quantities of various materials Dsource wise

are given in the following sections.

01 CO'T ANA4'I' O CONCRETE ;ITH MI> DE'IGN 0I' CODE

METHOD

1 'ource o! san$ & @6arat5a$i 0 Ma!96e$ Desi/n

M!=&1:1.++:3.1, 7" 5ei/6t

uantities of materials of hardened concrete in dry condition for / cum are found out

as given below.

a ty of cement L/.'4;D/M/.''M7./#

L /.'4;'.?/

L $.(#8cum;$.$7'

L ?.#9 bags D794.(9!g

7


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2 Lource o! san$ & -a6e

Desi/n i=&1:1.,2:3.12

(6) uantity of cement L D$.(#9cum L ?,## bags L D797.(?!g

(6)uantity of sand L /.#( 797.(?!g L #($.8$!gD$.77cum

D9 uantity of aggregate L 7,/( 797.(? L //8'.9$!g D$.?'7cum

Thus the cost economics of concrete prepared by using design mi and farma

mi are presented in the form of tables given below.

02 CO'T ANA4'I' O CONCRETE ;ITH ARMA MI>

0?olue -atc6in/


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uantity of cement L /.'4;D/M7M4

L /.'4;9 L $./8('cum;$.$7' L '.'$ bags

uantity of sand uantity of aggregate L 7 $./8(' cum L$.'?? cum

L 4 $./8(' cum L$.?? cum

The actual cost analysis of concrete prepared by both the methods is shown in

cables given below.

TA-4E NO 21. CO'T ANA4'I' O CONCRETE 0!or 1 cu ;ITH MI>

DE'IGN 0I' CODE METHOD

'#.

No.

T"#e o! '#

Mi=

Ratio

Material


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TA-4E NO.2% COMPARATI?E CO'T AND 'TRENGTH ANA4'I' O

'I.

No.

T"#e

o! '#

Concrete 7" Desi/n Mi= Concrete 7" ara Mi=

Mi= Ratio Cost 0Rs 'tren/t6

0MPa

Mi= Ratio Cost

0Rs

'tren/t6

0MPa

/ " //.#(7./( /99#.'$ 3).2% /(7

/77

/74

1((*.))

/?7(.'4

/#7$.8$

3).(+

(4./4

77./9

( "! //.'(7./# /987.8/ 3*.21 /(7

/77

/74

1((*.))

/?7(.'4

/#7$.8$

33.1(

(8.8(

(7.9'

7 " //'(7/# /987.8/ 3+.% /(7

/77

/74

1((*.))

/?7(.'4

/#7$.8$

%1.%(

7$.9/

(9.99

)rom the results shown in the above table, it is seen that the concrete

prepared by using farma mi with a mi ratio of /(7 gives almost same

compressive strength as that of the strength obtained for the concrete designedby i design process DI" code method. 6ence, it can be safely

recommended to the local contractor>s if-

1. concrete is to be manufactured using farma Dvolumetric method

2. sand is to be procured from the sources located at ahe, Nharatwadi

and al!hed from


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Comparitive Strength & Cost of Concrete

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