8/10/2019 Comparitive Strength & Cost of Concrete
1/60
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
R.I.T. Sakharale 1
8/10/2019 Comparitive Strength & Cost of Concrete
2/60
Comparative strength & cost of concrete by mix design & farma mix Design
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.
R.I.T. Sakharale 2
8/10/2019 Comparitive Strength & Cost of Concrete
3/60
Comparative strength & cost of concrete by mix design & farma mix Design
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.
R.I.T. Sakharale 3
8/10/2019 Comparitive Strength & Cost of Concrete
4/60
Comparative strength & cost of concrete by mix design & farma mix Design
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.
R.I.T. Sakharale 4
8/10/2019 Comparitive Strength & Cost of Concrete
5/60
Comparative strength & cost of concrete by mix design & farma mix Design
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 "
8/10/2019 Comparitive Strength & Cost of Concrete
6/60
Comparative strength & cost of concrete by mix design & farma mix Design
=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.
8/10/2019 Comparitive Strength & Cost of Concrete
7/60
Comparative strength & cost of concrete by mix design & farma mix Design
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 ($mm are generally considered satisfactory.
'6a#e o! A//re/ate
R.I.T. Sakharale 7
8/10/2019 Comparitive Strength & Cost of Concrete
8/60
Comparative strength & cost of concrete by mix design & farma mix Design
Roun$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.
8/10/2019 Comparitive Strength & Cost of Concrete
9/60
Comparative strength & cost of concrete by mix design & farma mix Design
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.
R.I.T. Sakharale 9
8/10/2019 Comparitive Strength & Cost of Concrete
10/60
8/10/2019 Comparitive Strength & Cost of Concrete
11/60
Comparative strength & cost of concrete by mix design & farma mix Design
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
8/10/2019 Comparitive Strength & Cost of Concrete
12/60
Comparative strength & cost of concrete by mix design & farma mix Design
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.
R.I.T. Sakharale 12
8/10/2019 Comparitive Strength & Cost of Concrete
13/60
Comparative strength & cost of concrete by mix design & farma mix Design
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.
8/10/2019 Comparitive Strength & Cost of Concrete
14/60
Comparative strength & cost of concrete by mix design & farma mix Design
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:
R.I.T. Sakharale 14
8/10/2019 Comparitive Strength & Cost of Concrete
15/60
Comparative strength & cost of concrete by mix design & farma mix Design
* 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
R.I.T. Sakharale 15
8/10/2019 Comparitive Strength & Cost of Concrete
16/60
Comparative strength & cost of concrete by mix design & farma mix Design
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$$$ !g;m .
In&situ concrete:
Concrete, which whilst in its plastic state, is deposited in the location where it
is required to form apart of the structure.
4ean concrete:
8/10/2019 Comparitive Strength & Cost of Concrete
17/60
Comparative strength & cost of concrete by mix design & farma mix Design
"tructural light weight aggregate concrete which is prestressed.
Pol"er concrete:
Concrete which is impregnated with apolymer compound or has polymer as
binder, to improve certain properties.
Pu#e$ concrete:
Concrete which is transported from the mier or delivery point of ready mied
concrete to the placing position by being pumped through a pipeline.
Rea$"&i=e$ concrete:
Concrete made at a place away from the construction site and conveyed in
special vehicles, delivered ready to use.
Re!ractor" concrete:
Concrete made with insulating Dli!e bric! aggregates and high alumina
cement for use in shielding or damping of heat.
Rein!orce$ concrete:
Concrete in which bars or fabric, usually of steel, are embedded in such a
manner that the two materials act together under load.
Rolle$concrete:
Concrete having a high aggregate cement ratio, which is compacted by a
road-roller and used as abase for road construction.
'a5 $ust concrete:
Concrete prepared by miing 1ortland cement with sawdust in specified
proportions in addition to concrete.
'6oc9 concrete:
Concrete compacted by dropping fresh concrete in a mould through a
predetermined height.
'#un concrete: Concrete compacted by centrifugal action.
'tructural li/6t 5ei/6t a//re/ate concrete:
Concrete having a density not eceeding /,9$$ !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
R.I.T. Sakharale 17
8/10/2019 Comparitive Strength & Cost of Concrete
18/60
Comparative strength & cost of concrete by mix design & farma mix Design
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
8/10/2019 Comparitive Strength & Cost of Concrete
19/60
Comparative strength & cost of concrete by mix design & farma mix Design
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
R.I.T. Sakharale 19
8/10/2019 Comparitive Strength & Cost of Concrete
20/60
Comparative strength & cost of concrete by mix design & farma mix Design
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
R.I.T. Sakharale 20
8/10/2019 Comparitive Strength & Cost of Concrete
21/60
Comparative strength & cost of concrete by mix design & farma mix Design
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
R.I.T. Sakharale 21
8/10/2019 Comparitive Strength & Cost of Concrete
22/60
Comparative strength & cost of concrete by mix design & farma mix Design
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
R.I.T. Sakharale 22
8/10/2019 Comparitive Strength & Cost of Concrete
23/60
8/10/2019 Comparitive Strength & Cost of Concrete
24/60
Comparative strength & cost of concrete by mix design & farma mix Design
d. "urface area method
e. Indian
8/10/2019 Comparitive Strength & Cost of Concrete
25/60
Comparative strength & cost of concrete by mix design & farma mix Design
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.
R.I.T. Sakharale 25
8/10/2019 Comparitive Strength & Cost of Concrete
26/60
Comparative strength & cost of concrete by mix design & farma mix Design
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
8/10/2019 Comparitive Strength & Cost of Concrete
27/60
Comparative strength & cost of concrete by mix design & farma mix Design
)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
8/10/2019 Comparitive Strength & Cost of Concrete
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
*.,
(.
(.%
(.*
(.(
8/10/2019 Comparitive Strength & Cost of Concrete
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
8/10/2019 Comparitive Strength & Cost of Concrete
30/60
8/10/2019 Comparitive Strength & Cost of Concrete
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
8/10/2019 Comparitive Strength & Cost of Concrete
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.
8/10/2019 Comparitive Strength & Cost of Concrete
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.
8/10/2019 Comparitive Strength & Cost of Concrete
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
8/10/2019 Comparitive Strength & Cost of Concrete
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
8/10/2019 Comparitive Strength & Cost of Concrete
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
8/10/2019 Comparitive Strength & Cost of Concrete
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 %
8/10/2019 Comparitive Strength & Cost of Concrete
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
8/10/2019 Comparitive Strength & Cost of Concrete
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
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
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
8/10/2019 Comparitive Strength & Cost of Concrete
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
8/10/2019 Comparitive Strength & Cost of Concrete
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 - (.$ %
Therefore, required sand content as percentage of total aggregate by absolute
volume L7' -(.$ L77 %
8/10/2019 Comparitive Strength & Cost of Concrete
42/60
8/10/2019 Comparitive Strength & Cost of Concrete
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= $esi/n !ro 8arious tests on
ingredients.
/ rand of Cement irla sha!ti
( Type of cement &pe
7 "pecific 3ravity of cement 7./'
4 =egree of quality control 3ood
' Type of eposure ild
# Type of fine aggregate :atural sand
? "pecific gravity of fine aggregate (.#'
9 2ater absorption of fine aggregate /.'%
8 aimum si+e of aggregate ($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
II. Tar/et ean stren/t6 of concrete for a tolerance factor of /.#' and using table
8/10/2019 Comparitive Strength & Cost of Concrete
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 ((.#
8/10/2019 Comparitive Strength & Cost of Concrete
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 -$.'$%
Therefore, required sand content as percentage of total aggregate by absolute
volume L7' -$.'$ L74.'$ %
)or '!g of cement
2ater L '.$/# lit
"and L?.?'(!g
*ggregate ($mmL8.'$4!g
*ggregate /(mm L #.77 !g
8/10/2019 Comparitive Strength & Cost of Concrete
46/60
8/10/2019 Comparitive Strength & Cost of Concrete
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$
8/10/2019 Comparitive Strength & Cost of Concrete
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
Cement - '$ !g - 7!g
"and -/(8.4$#!g -/$.7' !g
*ggregate -/##.#79!g -/7.77 !g
8/10/2019 Comparitive Strength & Cost of Concrete
49/60
2;C ratio - D(.$;4 L$.'$
DC or -a6e san$
a. Pro#ortion -1:3:3
Cement - '$ !g - 4!g
"and . -/84./$#!g -/'.'( !g
*ggregate- /##.#7!g - /7.7((!g
2;C ratio - D(.';4 L$.#('
7. Pro#ortion &1:3:%
Cement - '$ !g - 7!g
"and -/84./$#!g -/'.'( !g
*ggregate -(((./94!g -/?.?? !g
2;C ratio - D(.(' % L$.'#
c. Pro#ortion 1:2:3
Cement - '$ !g - 7!g
"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/$$tonnes capacity as per the standard procedure laid
down in handboo! of concrete mies. The crushing load was noted at the initiation of
first crac! on the concrete face for every cube specimens. The details of the test
results are tabulated in the table no /#.
Table no. /# "ource of sand - Nharatwadi
8/10/2019 Comparitive Strength & Cost of Concrete
50/60
"r
:o.
:o of
days
"pecimen
no
Hoad at
failure
Cross
sectional
area of
bloc!
Target
compressive
strength MPa
*verage
compressive
strength 1a
/ (9 N/ 9/.' (('$$ 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 -(('$$ sqmm >
8/10/2019 Comparitive Strength & Cost of Concrete
51/60
"I
:o.
"p.
No
i
1roportion
Hoad at
failure
Target comp
strength 1a
*verage comp
strength 1a
/ @1 /77 #'$$ (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.$$
8/10/2019 Comparitive Strength & Cost of Concrete
52/60
Ta7le no. 2. Test Results o! -a6e 'an$
'o
No.
'#ecien
no
Mi= Ratio 4oa$ at
!ailure
Tar/et co#
stren/t6B MPa
A8/ co#
stren/t6B MPa
/ -1 /77 '#$$ (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.//
8/10/2019 Comparitive Strength & Cost of Concrete
53/60
8/10/2019 Comparitive Strength & Cost of Concrete
54/60
8/10/2019 Comparitive Strength & Cost of Concrete
55/60
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 $.(#8cum;$.$7'
L ?.#9 bags D794.(9!g
7
8/10/2019 Comparitive Strength & Cost of Concrete
56/60
2 Lource o! san$ & -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/
8/10/2019 Comparitive Strength & Cost of Concrete
57/60
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
8/10/2019 Comparitive Strength & Cost of Concrete
58/60
8/10/2019 Comparitive Strength & Cost of Concrete
59/60
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
8/10/2019 Comparitive Strength & Cost of Concrete
60/60
Top Related