Grade M35 Concrete , cement test and aggregate test done at Bhagalpur College of Engineering

1. 1
PROJECT REPORT ON CONCRETE MIX
DESIGN OF
GRADE M-35
Submitted for the purpose of fulfillment of the requirement for the degree of
Bachelor of Technology
In
Civil Engineering
June 7, 2017
Under The Guidance of
Prof. Dr. Nirmal Kumar (Principal BCE, Bhagalpur)
&
Prof. Manikant Mandal
(HOD)
DEPARTMENT OF CIVIL ENGINEERING
BHAGALPUR COLLEGE OF ENGINEERING, SABOUR
BIHAR-813210
AFFILIATED TO ARYABHATTA KNOWLEDGE UNIVERSITY
PATNA, BIHAR

2. 2
INDEX
SERIAL
NO.
PARTICULARS PAGE
1. Introduction 5-6
2. Designof Mix Concrete 7-9
ACKNOWLEDGEMENT
With deep reference and immense please I express my sincere thanks to Prof.
Manikant Mandal (HOD Civil Engineering) B.C.E Bhagalpur, Bihar, for giving me
golden opportunity to do the project work with M35
concrete Mix Design. This project would not have been possible without their
help and permission.I would liketo extend my gratitudeto Mrs.AradhanaSingh
(Structural Engineer, M.Tech - NIT Patna); Mr. Raj Hansh Gupta (Lab Incharge,
Civil Engg., BCE Bhagalpur ); BaleshwarJi (Lab Assistant, Civil Engg., BCE
Bhagalpur); Mr. Arun Kumar (Lab Assistant, CivilEngg., BCE Bhagalpur) for their
valuable time that they gave me amidst their busy schedule.
Last but not least I would like to thank all the staff members and employees at
Civil Engineering Department of Bhagalpur College Of Engineering, who have
been very co-operative to me.

3. 3
3. Testingof Cement 10-13
4. Testfor Aggregates 14-21
5. Concrete Mix Designof Grade M 35 22-26
6. Testingof Concrete Mix Design 27-30
7. QualityMonitoringatSite 31
8. ExperimentalResults 32-33
9. Personal comments:Mistake,which
affectthe qualityof Concrete
33

4. 4
ABSTRACT
The method of concrete mix design consists of selection of optimum
proportions of ingredients, i.e., water, cement, fine and coarse aggregate and
admixture if needed to produce concrete of specified properties such as
strength, workability1
, durability, etc. as economically as possible. The
compressivestrength of hardened concrete which is generally considered to be
an index of its other properties, depends upon many factors, e.g. quality and
quantity of cement, water and aggregates; batching and mixing; placing,
compaction and curing. Thecostof concreteis madeup of the costof materials,
plant and labour. The variations in the cost of materials arisefrom the fact that
the cement is severaltimes costly than the aggregate, thus the aim is to produce
as lean mix.
The proportions of concrete mix are obtained by experimentally evolved
relationship between the factors in the choice of mix design. It provides
reasonably accurate guidelines to arrive at an optimum proportion of
ingredients. The preliminary trail mixes2
are made and checked. Further,
suitable adjustments are made and process is repeated until the satisfactory
proportions of ingredients are achieved, which possess specified properties
both in freshand hardened states with maximum overalleconomy. Thefinal mix
proportions areobtained on the basis of trial mixes. The results of sieve analysis
of aggregates are given in table 1, 2, 3 & 4. The fine and coarse aggregates are
mixed in suitable proportionto obtain recommended gradingof combinecoarse
aggregate.
1
The proportioning of ingredient of concrete is governed by the required performance of concrete in two states,
namely the plastic and the hardened states. If the plastic concrete is not workable, it cannot be properly placed
and compacted. The property of workability is therefore of vital importance.
2
A trail mix { According to Canadian Portland Cement Association,the trail mix approach is best for selecting
proportionsfor concrete} is a preliminary batch of concrete mixed in the MIT laboratory to test the ingredients
calculated theoretically actually meetsthe specified requirements.

5. 5
INTRODUCTION
Concrete mix design may be defines as the art 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.
Objectives of Mix Design
• To achieve the designed/ desired workability in the plastic stage • To achieve
the desired minimum strength in the hardened stage
• To achieve the desired durability in the given environment conditions • To
produce concrete as economically as possible.
Basic Considerations
• The following point must be considered while designing concrete mixes.
• Cost
• Specification
• Workability
• Strength and Durability
Cost
• The cost of concrete is made up of
• Material Cost
• Equipment Cost
• Labour Cost
Specifications
• The following point may be kept in mind while designing concrete
• Minimum Compressive Strength required
• Minimum water/ cement ratio
• Maximum cement content to avoid shrinkage cracks
• Maximum aggregate / cement ratio
Workability
•The following points related to workability
shall be kept in mind while designing
concrete mixes.
•The consistency of concrete should no more
than that necessary for placing, compacting
and finishing.

6. 6
•For concrete mixes required high consistency at the time of placing, the use
of water-reducing and set-retarding admixtures should be used rather than the
addition of more water
• Wherever possible, the cohesiveness and finishibility of concrete should be
improved by increasing sand/aggregate ratio than by increasing the
proportion of the fine particles in the sand.
Strength and Durability
• Strength and durability requirelower w/c ratio. It is usually achieved not by
increasing the cement content, but by lowering the water at given cement
content. Water demand can by lowered by throughoutcontrol of the
aggregate grading and by using water reducing admixtures.
GRADE OF CONCRETE
Group Grade designation Characteristics compressive strengt
of 150 mm cube at 28 days, N/mm2
Ordinary Concrete M10
M15
M20
10
15
20
Standard Concrete M25
M30
M35
M40
M45
M50
M55
25
30
35
40
45
50
55
High Strength Concrete M60
M65
M70
M75
M80
60
65
70
75
80

7. 7
Design Mix Concrete
The concrete mix produced under quality control
keeping in view the strength, durability, and
workability is called the design Mix.
Others factors like compaction equipment's
available, curing method adopted, type of
cement, quality of fine and coarseaggregate etc.
have to be kept in mind beforearriving at the
mix proportion.
The design mix or controlled mix is being used
more and morein variety of important
structures, becauseof better strength, reducedvariability, leaner mixed with
consequenteconomy, as well as greater assuranceof the resultant quality.
IS Method of Mix Design
• The Bureau of Indian Standards, recommended a set of procedure for design of
concrete mix. The procedure is based on the research work carried out at national
laboratories.
Data for mix design
• The following basic data are required to be specified for design a concrete mix
• Characteristic Compressive strength only a few specified proportions of test

8. 8
results are expected to fall of concrete at 28 days (fck); Degree of workability
desired.
• Limitation on water/Cement Ratio with the minimum cement to ensure
adequate durability
• Type and maximum size of aggregate to be used.
• Standard deviations of compressive strength of concrete.
Target Strength for Mix Design
• The target average compressive strength (fck) of concrete at 28 days is given by
• Fck= f ck + t.s
Where,
• Fck= target average compressive strength at 28 days
• F ck= characteristics compressive strength at 28 days
• s= Standard deviation
• t= a stastical value, depending upon the accepted proportion of low results and
the number of tests.
• According to Is 456: 2000 and IS 1343:1980 te characteristic strength is defined
as the value below which not more than 5 percent of results are expected to fall.
In such cases the above equation reduced to Fck= fck + 1.65 s
• The value of standard deviation is obtained from the table
Step-II
Selection of Water –Cement Ratio
Since different cements and aggregates of different maximum sizes, grading,
surface texture shape and other characteristics may produce concrete of different

9. 9
compressive strength for the same free water cement ratio, the relationship
between strength and free water cement ratio should preferable be established
for the material actually to be used. In the absence of such data, the preliminary
free water-cement ratio corresponding to the target strength at 28 days may be
selected from
Step III : Estimation of Air Content
Approximate amount of entrapped air to be expected in normal concrete is given
in table 9.6
StepIV: Selectionof Water Content and fine to total aggregate ratio
• For the desired workability the quantity of mixing water per unit volume of
concrete and the ratio of fine aggregate(sand) to total aggregate by absolute
volume are to be estimated from table below as applicable. Depending upon
the nominal maximum sizeand type of aggregate.
Approximate Sand and water Content per Cubic Metre of Concrete for Grades
up to M 35 W/C = 0.6 Workability=0.8 C.F
StepV: Calculationof Cement Content
• The cement content per unit volume of concrete may be calculated from the
free water-cement ratio obtained in step- 2, and the quantity of water per unit
Nominal Maximum Size of Aggregates Entrapped Air, as percentage of volume of concrete
10 3 %
20 2 %
40 1 %

10. 10
volume of concrete obtained in step-4
• The cement content so obtained should be checked againstthe minimum
cement content for the requirement of durability as per table 5 IS 456:2000
and the greater of the two value is adopted.
StepVI: Calculationof Aggregate Content
• With the quantities of water and cement per unit volumeof concrete and the
ratio of fine to total aggregate already determined, the total aggregate content
per unit volume of concrete may be calculated using following values
Where,
• V= Absolutevolume of fresh concrete (m3)
• W= Mass of Water (kg) per m3 of concrete
• C= Mass of Cement (Kg) per m3 of concrete
• Sc= Specific gravity of cement say 3.15
• P= ratio of fine aggregate to total aggregate by absolute volume
• Fa and Ca = Total masses of fine aggregate and coarseaggregate (kg) / m3 of
concrete mass respectively
• Sfa, Sca= Specific gravities of saturated surfacedry fine aggregate and coarse
aggregate respectively
Normally Sfa=2.6 and Sca= 2.7
Testing of Cement
1. Field testing
2. Standard consistency test
3. Fineness test
4. Soundness test 5. Strength test
Field Testing
• Open the bag and take a good look at the cement, then it should not contain any
visible lumps.
• Colour of cement should be greenish grey. • Should get cool feeling when
thrusted.
• When we touch the cement, it should give a smooth &not a gritty feeling.
• When we throw the cement on a bucket full of water before it sinks the particles
should flow.
• When we make a stiff paste of cement & cut it with sharp edges & kept on a
glass plate under water there wont be any disturbance to the shape& should get
strength after 24hours.
Standard Consistency Test
Objective:
Used to find out the percentage of water required to produce a cement paste of
standard consistency.This is also called normal consistency (CPNC).

11. 11
Theory:
The standard consistency of a cement paste is defined as that consistency which
will permit a Vicat plunger having 10 mm diameter and 50 mm length to penetrate
to a depth of 33-35 mm from the top of the mould.
PROCEDURE:
•For first trial, take about 500gms of cement & water of 24%by weight of cement.
•Fill it in Vicat’s mould with in 3-5min.
•A standard plunger, 10 mm diameter, 50 mm long is attached and brought down
to touch the surface of the paste and quickly released.
•Note the reading according to depth of penetration of the plunger.
• Conduct trials continuously by taking different water cement ratios till the
plunger penetrates for a depth of 33-35mm from top.
• This particular percentage is known as percentage of water required to produce
cement paste of standard consistency.
• This is usually denoted as ‘P’.
SUITABLE CONDITIONS:
• Conducted in a constant temperature of 270+20C.
• Constant Humidity 90%.
Setting Time Test
• An arbitraty setting time division has been made for the of cement.
• Initial setting time &
• Final setting time.

12. 12
INITIAL SETTING TIME
• The time elapsed between the
moment that the water is added to the
cement, to the time that the paste
starts losing its plasticity.
• Normally a minimum of 30min has
maintained for mixing & handling
operations.
• It should not be less than 30min.
FINAL SETTING TIME
• The time elapsed between the moment the water is added to the cement, and
the time when the paste has completely lost its plasticity and has attained
sufficient firmness to resist certain definite pressure.
• It should not exceed 10hours.
• So that it is avoided from least vulnerable to damages from external activities.
FINENESS TEST
• The fineness of cement has an important bearing on the rate of hydration, rate
of gain of strength, evolution of heat.
• Finer cement offers greater surface area.
• Disadvantage of fine grinding is that it is susceptible to air set & early
deterioration.
• Maximum no. of particles in a sample of cement<100microns.
• The smallest particle should have a size if 1.5microns.
• Large particle should have a size of 10microns.
• Fineness of cement is tested in two ways. • By sieving.
• By determination specific surface by air permeability method.
SOUNDNESS TEST
• It is very important that the cement after setting shall not undergo any
appreciable change of volume.
• This test is to ensure that the cement does not show any subsequent
expansions.
• The unsoundness in cement is due to the presence of excess of lime combined
with acidic oxide at kiln.
• This is due to high proportion of magnesia & calcium sulphate.
• Therefore magnesia content in cement is limited to 6%.
• Gypsum 3-5.

13. 13
APPARATUS FOR SOUDNESS TEST
• It consists of a small split cylinder
of spring brass.
• It is 30mm diameter & 30mm
high.
• Cement is gauged with 0.78 times
& filled into the mould & kept on a
glass plate & covered with another glass plate.
• This is immersed in water at a temperature 270c-320c for 24 hours.
• Measure the distance between indicators.
• Heat the water & bring to boiling point of about 25-30min. • Remove the mould
from the water after 3 hours.
• Measure the distance between the indicators.
• This must not exceed 10min for ordinary, rapid hardening, low heat Portland
cements.
• If this expansion is more than 10mm the cement is said to be unsound.
STRENGTH TEST
• This is the most important of all
properties of hardened cement.
• Due to excessive shrinkage and
cracking the strength tests are not
made on heat cement paste.
• Standard sand is used for finding
the strength of cement.
PROCEDURE
• Take 555gms of standard sand.
185gms of cement (i.e., 1:3 ratio of
cement and sand)
• Mix them for 1min, then add water of quantity (P/4)+3.0%.
• Mix three ingredients thoroughly until the mixture is of uniform colour.
• The time of mixing should not be<3min and >4min.
• Then the mortar is filled into a cube mould of 7.06cm. • Compact the mortar.
• Keep the compacted cube in the mould at a temperature of 27°C ± 2°C and at
least 90 per cent relative humidity for 24 hours.
• After 24hours the cubes are removed & immersed in clean fresh water until
taken for testing.

14. 14
Test for Aggregate
Objective:
To determine surface moisture in fine aggregates.
Theory:
fine aggregate i.e. sand received from river bed or when exposed to rain retain
some amount of moisture for a considerable time. Also whenthe clay and silt
content in aggregates is more than 6%, fine aggregates have to washed, where by
some moisture retaines in this aggregats, which when mixed with cementincrease
effectivewater cement ratio anf if no allowance is made for that resultmin weak
concrete. in order to determine the net w/c ratio for a batch of concrete, the
amountof this retained water of this fine aggregate has to be calculated. these are
the two method of calculating this:
1. by displacement method
2. by drying ( frying pan method)
Materials:
A sample of fine aggregate containing moisture.
Procedure:
1. Fill the container with water upto the mark and note the weight.
2. Empty the container .
3. Now fill aggregate sample to be tested(not less than 200gms) in container full of
water.
4. Top up water upto the mark, remove entrained air and weigh it again.
Recording of Observations:
1. Weight of moist sample W= 2500gms
2. Weight of container full of water Wa = 2700 gms
3. Weight of container, aggregate and water Wb
so, weight of water displaced= W+Wa-Wb
specific gravity of surface dry aggregate = 2.65
moisture surface % i.e. Ѡ=
𝒘𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒘𝒂𝒕𝒆𝒓 𝒅𝒊𝒔𝒑𝒍𝒂𝒄𝒆𝒅 −𝒘𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒔𝒂𝒎 𝒑𝒍𝒆
𝒘𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒔𝒂𝒎 𝒑𝒍𝒆
× 𝟏𝟎𝟎
Note:
An average of a minimum of three sample be taken.

15. 15
2. Drying ( Frying Pan method)
Apparatus:
Weighing balance, tray for heating sample, thermostatically controlled heater.
Procedure:
- place about one Kg of aggregates containing moisture in the heating tray and
weight it.
- now place the tray on the heater and heat the sample till dry.
- weigh the dried aggregate with tray.
-empty the tray of dried aggregates and weight the tray.
Recording of observation:
(i) Weight of tray and moist sample W1 = 1254 gms
(ii) Weight of tray and dry sample W2 = 1233 gms
(iii) Weight of tray W3 = 254 gms
Calculations:
- Weight of dry aggregate (W2-W3) = 979 gms
- moisture (by difference) (W1-W2) = 21 gms
- moisture content % =
(𝑊1−𝑊2)
(𝑊2−𝑊3)
× 100 (in terms of weight of surface dry
aggregate)
= (21/979) x 100 = 2.1 %
Precautions:
1. Heat should be applied gradually.
2. aggregate should be turned over during drying period in order to prevent over
heating of a portion of the aggregate.
3. aggregate should dried and weighted until there is no further loss of weight in
order to ensure complete drying of aggregates.
3. Bulking of Fine Aggregate
Objective: To study
- Phenomenon of bulking of fine aggregates and to draw a curve between water
content and bulking.
- to determine bulking of fine aggregate in the field.
Theory:
Fine aggregate i.e. sand has the tandency to increase in volume (Bulk) depending
upon the amount of moisture present in it. Specially when bitching is done by
volume the quantity od sand in each batch has to be related to the volume od
cement otherwise the batch shall be richer than specified. therefore it is necessary
to increase the amount of sand used by percentage bulking which is

16. 16
=
𝐵𝑢𝑙𝑘𝑒𝑑 𝑣𝑜𝑙𝑢𝑚 𝑒− 𝐷𝑟𝑦 𝑉𝑜𝑙𝑢 𝑚 𝑒
𝐷𝑟𝑦 𝑉𝑜𝑙𝑢 𝑚 𝑒
× 100
Materials:
Sample of oven dry sand.
Apparatus:
A container, graduated cylinder, Beaker, Metal tray, Steel rod, Weighing balance.
Procedure:
-Sufficient quantity of oven dry sand was taken and it was filled in the graduated
cylinder uto a certain fixed mark.
- empty the sand into the container and weight it.
- calculate the weight of sand after deducting the weight of container.
-add 1% water by weight od sand and mix it thoroughly.
-fill the graduate cylinder now with this sand (moist) and note its volume.
- increase the percentage of water every time by 1% and note its volume after
filling in the graduate scale.
- go on increasing the % of water by the same increment till the volume of sand
starts decreasing and the sand comes back to original volume i.e. volume of dry
sample.
Recording of observations:
1. weight of oven dry sand= 300 gms

17. 17
OBSERVATION TABLE
3. Draw a graph between moisture content and % increase in volume.
from the graph it shall be seen that bulking increases with the increase in moisture
content upto a certain point (maximum) then it decreases to practically nil when
sand is fully saturated ( mandated by water).
FLAKINESS INDEX AND ELONGATION INDEX OF COARSE AGGREGATE
OBJECTIVE:
To detremine Flakiness Index and elongation Index of coarse aggregate.
THEORY:
Flakiness index os an aggregate is the % by weight of particle in it whose least
dimensions (thickness) is less than 3
5⁄ th of its mean dimension passing through
50mm and retained an 40mm is (
50+40
2
)=45.5mm. if the least dimension is less
than
3
5
× 45.4 = 136.5
5⁄ = 27.3𝑚𝑚
the material is classifies as flaky.
On account of large number of flaky particles in aggregate more voids are 1 in the
concrete, which requires large amount of sand, cement and water as for balance
sizes. durability of concrete is also affected by the partcles tend to orient in one
plane and cause laminations.
ELONGATION INDEX:
The elongation index of an aggregate is the percentage by weight of particles
whose greatest dimension (length) is greater than one and four fifth (1
4
5
) times
their mean dimension.

18. 18
On account of large elongated particles more voids are formed in the concrete,
which requires large amount of sand, cement and water for same workability as
for balanced sizes.
MATERIAL:
Sample of coarse aggregates of known weight and size.
APPARATUS:
Balance,thickness guage, length guage , set of IS Sieves 63mm to 10mm (set of 10
sieves).
PROCEDURE:
1. FLAKINESS INDEX:
-Take sufficient quantities of aggregate to be tested so as to provide 200
pieces. (minimum) of any fraction.
-sieve the sample through I.S. Sieves as specified below.
-seperate the aggregate as reatined on the sieves.

19. 19
-pass each aggregate particle through corresponding slot in the thickness guage
e.g. material passing through 25mm guage but retained on 20mm guage is passed
through X = 13.5mm slot
- if the material pass through the slot, it is flaky.
- weight the material which has passed through the slot.
CALCULATIONS:
% Flakiness index =
𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑎𝑔 𝑔𝑟𝑒𝑔𝑎𝑡𝑒 𝑝𝑎𝑠𝑠𝑖𝑛𝑔 𝑡ℎ𝑟𝑜𝑢𝑔ℎ 𝑡ℎ𝑒 𝑠𝑙𝑜𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠 𝑔𝑢𝑎𝑔 𝑒
𝑡𝑜𝑡𝑎𝑙 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑎𝑚 𝑒
× 100
ELONGATION INDEX
After sieving the aggregate through corresponding sieves and seperating the
aggregate on each sieve
-pass each aggregate piece through the corresponding sot f length guage
correspondingto slot size given below:
corresponding size of slot for material passing through 25mm sieve but retained
on 20mm sieve is = weight all particles retained on length guage.

20. 20
CALCULATIONS:
% Elongation index =
𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑎𝑔𝑔𝑟𝑒𝑔𝑎𝑡𝑒 𝑟𝑒𝑡𝑎𝑖𝑛𝑒𝑑 𝑜𝑛 𝑙𝑒𝑛𝑔 𝑡ℎ 𝑔𝑢𝑎𝑔 𝑒
𝑡𝑜𝑡𝑎𝑙 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑎𝑔𝑔 𝑟𝑒𝑔𝑎𝑡𝑒
× 100
PRECAUTIONS:
* The maximum size of the given sample of coarse aggregate must be noted and
corresponding sieves of lesser dimensions be used for sieving.
*for calculation flakiness index use weight of aggregate pieces through thick guage
while for calculating elongation index weight of aggregate retained on length
guage be used.
To determine Specific Gravity and Water Absorption of
aggregates
OBJECTIVE:
To determine specific gravity and water absorption of aggregates.
THEORY:
Information regarding specific gravity of aggregates is necessary for design of
concrete mixes. If the specific gravity is above or below normal for a particular
type of aggregate, it is an indicator of change odd shape and grading.
The specific gravity of most of the sggregate is betwee 2.6 to 2.9 and is useful in
calculating void content.
Water absorption:
The water absorption value is the diffence in weight between the saturated
surface dry aggregate and very dry sample expressed as percentage of dry weight
of aggregate . It is of great importance to know the water absorption value of
aggregates for calculating total water be to added to the mixes.
PROCEDURE:
1. Thoroughly wash the 20 mm aggregates to remove any dust. Oven dry and
cool the aggregates for 1 to 3 hours and then immersein water for 24 hours.

21. 21
2. Remove the specimen fromwater and roll it in a large absorbentcloth until
all visible films of water are removed.
Weight the specimen in saturated surfacedry conditions.
3. Place the saturated surfacedry specimen in wire mesh bucketand weight it
in water. Shakethe bucketto removeall entrapped air beforeweighing
 Dry the sample to constant weight in oven, cool and weigh.
OBSERVATIONS
Weight of oven dried aggregatein air (gm) = A = 2493
Weight of saturated surfacedry aggregate in air (gm) = B = 2502
Weight of saturated aggregate and bucket in water (gm) = W1 = 3197
Weight of bucket in water (gm) = W2 = 1572
Weight of saturated aggregate in water = C (gm) = (W1 – W2) = 1625
CALCULATIONS
Oven Dried Bulk Specific Gravity = Sd = A / (B – C) = 2493/(2502-1625) = 2.842
Saturated Surface Dry Bulk Specific Gravity = Ss = B / (B – C)
= 2502 / ( 2502 – ( 3197-1572 )) = 2.853
Apparent Specific Gravity = Sa = A / (A – C) = 2493/(2943-1625) = 2.872
Water Absorption, = WA = [(B – A) / A] x 100 = [(2502-2493)/2493] x 100 = 0.361

22. 22
CONCRETE MIX DESIGN OF GRADE M-35
1 DESIGN STIPULATION
# Characteristic strength of concrete (fck) = 35 N/mm2
# Maximum size of Coarse Aggregate = 25-20 mm,
# Shape of aggregate = Angular (crushed)
# Degree of quality control = good as per IS 456
# Workability / Slump: 100-125mm for Pile Foundation works
# Type of exposure = Very sever as defined in IS 456, Page-20
2. TEST DATA FOR CEMENTS
a. Cement: Portland Pozzolana Cement conforming to the Indian IS specification
mentioned in IS 1489 (part 1) 1991.
b. SP Gravity of cement =3.15
c. Initial setting time of cement : 130 minutes, Final setting time: 203 minutes as
method described in IS 4031{ Part 5 }.
d. Fineness Value of cement : 3% (as per IS 4031 {part 1}
e. Soundness of cement : 1.00 mm (as per IS 4031 {part 3}
f. Compressive Strength of cement after 3 days – 25.0 Mpa.
g. Compressive Strength of cement after 7 days – 34.0 Mpa.
h. Compressive Strength of Cement after 28 days – 51.00 Mpa.
i. Standard Consistency (P) =30.0 percent water required for producing cement
past of standard consistency (IS 4031, Part 4-1988). It should be workable as
mentioned in IS- 8112): 1989
3. TEST FOR FINE AGGREGATES
# SP Gravity of fine aggregates (Sand)= 2.64 (IS 2386,Part 3)
# Silt Content : 0.2%
# Water absorption – 1.42%
# Free moisture available in sand =0.8%
________________________________________________________________
Variation in the quality of constituent materials used; variation in the mix proportions due
to batching process; variation in the quality of batching and mixing equipment available; the
quality of supervisions and workmanship and variation due to sampling and testing of
concrete specimens.
Good Quality Control means “Proper storage of cement weigh batching of all materials,
controlled addition of water, regular checking of all materials aggregate grading and
moisture content and periodical checking of workability of strength.
Table 1: Sieve Analysis: Fine Aggregate (natural river sand)

23. 23
Sieve size
In (mm)
Weight
retained
In (gm)
% Wt
retained
In (gm)
Cum.
Percentage
retained (%)
Percentage
passing
(%)
Remarks
10.000 0 0 0 100 Sand zone
II As per
IS 383
Limits for
Fine
Aggregates
4.750 20.5 2.05 2.05 97.95
2.360 47.5 4.75 6.80 93.2
1.180 115.5 11.55 18.35 81.65
0.600 289 28.9 47.25 52.75
0.300 372.5 37.25 84.50 15.50
0.150 138 13.8 98.30 1.70
0.075 13 1.3 99.60 0.40
Fineness Modulus (fm) = 3.57
4. TEST FOR COARSE AGGREGATES
 Sp Gravity of aggregates (20mm graded)= 2.77 (IS 2386, Part 3)
 Flakiness Index of coarse aggregates (20 mm Graded)= 21.5%
 Aggregate Impact Value :20mm down =16.5%
 Crushing Strength Value : 20mm down =15.5%
 Water absorption by coarse aggregates =0.45%
 Free surface moisture available in coarse aggregates =Nil
Table 2: Test Results of Sieve Analysis: Coarse Aggregate 20 mm : Amount =
5.00 kg
Sieve size
In(mm)
Weight
retained
In (kg)
% Wt
retained In
(Kg)
Cum.
Percentage
retained (%)
Percentage
passing (%)
40 0 0 0 100
20 0.457 9.14 9.14 90.86
10 4.207 84.14 93.28 6.72
4.75 0.285 5.7 98.98 1.02
2.36 0.030 0.6 99.58 0.42
1.18 0.1 100 100

24. 24
 Table 2: Test Results of Sieve Analysis: Coarse Aggregate 10 mm : Amount =
10.00 kg
Sieve size
In(mm)
Weight
retained
In (kg)
% Wt
retained in
(Kg)
Cum.
Percentage
retained (%)
Percentage
passing (%)
40 0 0 0 100
20 0.014 0.14 0.14 99.86
10 3.934 39.34 39.48 60.52
4.75 5.345 53.45 92.93 7.07
2.36 0.609 6.09 99.02 0.98
Pan 0.86 0.86 99.88 0.12
Fineness Modulus (fm) = 7.31
5. MIX DESIGN RECOMMENDATIONS
The mix design has been carried out as per the stipulation of Indian Standard
(IS 10262-1982)
Keeping in view the recommended standard deviation and target mean
strength.
5.1 Target Mean strength:
Considering the inherent variability of concrete strength during production, it
is necessary to design the mix to have a Target Mean Strength which is greater
than the characteristic strength by a suitable margin .In order to avoid the
likely fall of test results below the characteristic strength, the concrete mix has
to be designed for somewhat higher target averagecompressivestrength.
The target meanStrengthof Concrete
ft= fck+ k.s = 35+5*1.65 =43.25 N/mm2
{wherefck= 35 Mpa (stipulated), K= 1.65
(fromclause 3.2 of IS: 10262: 2009), s=5
(fromtable 1, IS 10262: 2009 & Table 8 of IS456, Page23 for good quality
control}
The combined mass of cement. sand and water obtained in the manner
described in IS 4031 (part6) 1988 for calculating the strength of cement
mortar cubes. For the other condition of workability. W/C ratio grading of fine
aggregates, certain adjustmentin the quantity of mixing water and fine to total
aggregates ratio have been made. W/C ratio is adopted equal to 0.45 for very
severeexposure (Table 5, IS 456, and Page 20). The total aggregate content per
unit volume of concrete has been calculated from the Table 3 and clause 4.4 n
IS 10262: 2009. Thecorrection Table -3 is made as follows:

25. 25
Table-3:Correctioninwater Content for more workable concrete
Parameter Standard
reference
condition
Value as per
present
problem
Departure Correction
Slump 25-50 mm 100-125mm 75 mm +9%
Shape of
Aggregate
Angular Angular 0.00 0.00
5.2 Maximumwater Content = 186liter {Table 2, IS 10262: 2009, Page3}. The
content of concrete is influence by a number of factors, thereforeit is adopted
as 1.09*186 =192liters for 1st
trail.
5.3. Cement Content = 202.74/O.45=450 Kg/m3
{From Table 5 of IS 456,
minimum cement content for severeexposure condition = 340 Kg/m3
and
450 Kg/m3
> 340 Kg/m3
, hence OK.)
5.4. Aggregate Proportion =0.62 ; from Table 3 -IS 10262: 2009, Page3,
volume of coarseAggregatecorresponding to 20 mm sizeaggregate and fine
aggregate zoneII ] for w/c =0. 45.
5.5. Estimationof Fine Aggregate Proportion =1- 0.62=0.38
5.6. Mix ingredients proportions of concrete for 1"Trail
 Volume of Concrete = 1 m3
 Volume of Cement = 450/3.15*1000 = 0. 143 m3
 Volume of water = 203/1000 = 0.203 m3
 Volume of all in Aggregate = 1- 0.143 - 0.203 =0.654 m3
 Volume of CoarseAggregate = 0. 406 m3
 Volume of Fine Aggregate = 0.249 m3
On the basis of 4th
trial. Concrete Mix casted with the materials supplied by the
client and test results for workability and 28 days strength obtained, the mix
proportions for concretewith Super plasticizer as given in Table 4 & 5 are
recommended for construction
___________________________________________________________________________
Depending upon thedegreeof quality control,thevalue of standard deviation may beadopted in mix
design as 6 N/ mm2
as per ISI 0262: 2009 Table I, Page:2

26. 26
Due to special consideration.i.e.,werequired high slump and high compaction factorforcasting of
foundation.TheminimumSlump should be100 mm.when concreteis notcompacted,butin any
case,it should notbe morethan I80 mm{IS 2911_1_1:1979}
Propercuring is extremely important.When sufficientcuring is not provided,therewould be loss In
strengthof concreteand also resulting in shrinkagecracksin concrete.
Table 4: Mix ingredientsproportions of concrete by volume m3
/m3
Concrete
Grade
Water Cement Fine
Aggregate
Coarse Aggregate
20mm Graded
M-35 202.5/1000
=0.2025
450/3.15*
1000=.143
0.249 0.406
Total Volume Concrete = 1.0005 =1 m3
/m3
Hence OK.
Table 5: Mix ingredientsproportions of Concrete by weight kg/m3
Concrete
Grade
Water Cement Fine Aggregate Coarse Aggregate
20mm Graded
M-35 202.5 450 0.249*2.67*1000
= 664.83
(0.141*2.7*1000)+(0.264*2.84*1000)
= 1136.986
Ratio 0.450 1 1.48 2.53
Quantities
per bag of
Cement
22.5 50 74.00 126.50
Slump: 100 – 125 mm
Ratio :- Cement : Sand : Aggregate by Weight ( 1 : 1.48 : 2.53 )

27. 27
6. TESTING OF CONCRETE MIX DESIGN
6.1 Concrete SlumpTest
Definition
 Slump is a measurementof concrete's workability, or fluidity.
 It's an indirect measurement of concrete consistency or stiffness.
A slump test is a method used to determine the consistency of concrete.
The consistency, or stiffness, indicates how much water has been used in
the mix. The stiffness of the concrete mix should be matched to the
requirements for the finished productquality
Concrete SlumpTest
The concrete slump test is used for the measurement of a property of fresh
concrete. The test is an empirical test that measures the workability of
fresh concrete. Morespecifically, it measures consistency between batches.
The test is popular due to the simplicity of apparatus used and simple
procedure.
Principle
The slump test result is a measureof the behaviour of a compacted
inverted cone of concrete under the action of gravity. Itmeasures the
consistency or the wetness of concrete.
Types Of Slump
The slumped concrete takes various shapes, and according to the profile of
slumped concrete, the slump is termed as;
1. Collapse Slump
2. Shear Slump
3. True Slump

28. 28
Collapse Slump
In a collapse slump the concrete
collapses completely. A collapse
slump will generally mean that the
mix is too wet or that it is a high
workability mix, for which slump
test is not appropriate.
Shear Slump
In a shear slump the top portion of
the concrete shears off and slips
sideways. OR
If one-half of the cone slides down
an inclined plane, the slump is said
to be a shear slump.
1. If a shear or collapse slump
is achieved, a fresh sample
should be taken and the test
is repeated.
2. If the shear slump persists, as may the case with harsh mixes, this is
an indication of lack of cohesion of the mix.
True Slump
In a true slump the concrete simply subsides, keeping more or less to
shape
1. This is the only slump which is used in various tests.
2. Mixes of stiff consistence havea Zero slump, so that in the rather dry
range no variation can be detected between mixes of different
workability.
However , in a lean mix with a tendency to harshness, a true slump
can easily changeto the shear slump type or even to collapse, and
widely different values of slump can be obtained in different samples
fromthe samemix; thus, the slump test is unreliable for lean mixes.
Applications of SlumpTest
1. The slump test is used to ensureuniformity for different batches of
similar concrete under field conditions and to ascertain the effects of
plasticizers on their introduction.
2. This test is very usefulon site as a check on the day-to-day or hour-
to-hour variation in the materials being fed into the mixer. An

29. 29
increase in slump may mean, for instance, that the moisture content
of aggregate has unexpectedly
increases.
3. Other cause would be a change in
the grading of the aggregate, such as
a deficiency of sand.
4. Too high or too low a slump gives
immediate warning and enables the
mixer operator to remedy the
situation.
This application of slump test as well as its
simplicity, is responsiblefor its widespread
use.
Apparatus
 Slump cone,
 Scale for measurement,
 Temping rod (steel)
Procedure of Concrete Slumptest:
1. The mould for the slump test is a frustum of a cone, 300 mm (12 in) of
height. The baseis 200 mm (8in) in diameter and it has a smaller
opening at the top of 100 mm (4 in).
2. The base is placed on a smooth surfaceand the container is filled with
concrete in three layers, whoseworkability is to be tested.
3. Each layer is temped 25 times with a standard 16 mm (5/8 in) diameter
steel rod, rounded at the end.
4. When the mould is completely filled with concrete, the top surfaceis
struck off (levelled with mould top opening) by means of screening and
rolling motion of the temping rod.
5. The mould must be firmly held against its baseduring the entire
operation so that it could not move due to the pouring of concrete and
this can be done by means of handles or foot - rests brazed to the
mould.
6. Immediately after filling is completed and the concrete is levelled, the
cone is slowly and carefully lifted vertically, an unsupported concrete
will now slump.

30. 30
7. QUALITY MONITORING AT SITE
7. The decrease in the height of the centre of the slumped concrete is
called slump.
8. The slump is measured by placing the cone justbesides the slump
concrete and the temping rod is placed over the cone so that it should
also come over the area of slumped concrete.
9. The decrease in height of concrete to that of mould is noted with scale.
(Usually measured to the nearest 5 mm (1/4 in).
Precautions
In order to reduce the influence on slump of the variation in the surface
friction, the inside of the mould and its base should be moistened at the
beginning of every test, and prior to lifting of the mould the area
immediately around the baseof the cone should be cleaned from concrete
which may have dropped accidentally

31. 31
 Quantity of water may be depending upon the weather conditions to
get the desired workability. Therecommended quantity of water is for
the saturated surface dry condition.
 Water used formixing and curing shallbeclean and freefrom injurious
amounts of oils. Acids, alkalis, salts, sugar, organic materials or other
substances. Itis good to use potable quality of water. This is the least
expensive, but most important ingredients of concrete. Water fit for
drinking is also fit for concrete. PH value of water should not be less
than 6.
 For variation in the gradingof aggregate of the order of ± 10%,the mix
design holds good.
 Use fresh cement for concrete mix. {Cement after 3 months storage,
strength reduced by 20%}
 In order to make the concrete impervious & attain its maximum
strength, it is required to removethe entrapped air from the concrete
mass when it is still 1n plastic state.
 If the air is not removed completely, the concrete loses strength
considerably. Ithas; been observed that 5% voids reduce the strength
by about 30% and 10% voids!Reduce the strength by over 50%. There
ISinverserelationship between strength and porosity.Concretewillbe
compacted according to the requirements given in IS 516.
 Compaction eliminates air bubbles and brings enough fine material
both to the surfaceand againstthe formsto producethe desired finish

32. 32
Mechanical vibrators are best to reach the bottom of the form and be
small enough to pass between reinforcing bars. 1
 From Quality control point of view implement appropriate mixing,
proper compaction correct placement of concrete within 30 minutes
and adequatecuring13
at site.
 The recommended quantity of cement as per Design Mix is for a given
workability of concrete. Extra cement is not required to achieve the
desired strength.
 The site Engineer deputed by b the Agency is required to make
concrete at site closely following the parameters suggested above.
 The Executing Agency is required to cast sufficient numbers of cubes
at site for strength testing
 Slump of fresh concreteshould be measured at site in presenceof site
Engineer to check the consistency and workability of the concrete.
 In case of any discrepancy/inconsistency in recommended strength,
the agency should report it to undersigned for another trail mix.
8. EXPERIMENTAL RESULTS
Table 6: 7 day’s strengthof Concrete
Sample No Load
taken(Kg)
Compressive
Strength(N/mm2
)
Average
Strength at 7
days
Deviation
from
average
value
I
II
III
73000
74000
72000
32.44
32.88
32.00
32.44 N/mm2
0.00 %
+1.36 %
-1.36 %
Table 7: 28 day’s strength of Concrete

33. 33
Sample No Load
taken(Kg)
Compressive
Strength(N/mm2
)
Average
Strength at 28
days
Deviation
from
average
value
I
II
III
95000
98000
99000
42.22
43.55
44.00
43.26 N/mm2
-2.40 %
+0.67 %
+1.71 %
a. 7 Days strength = 32.44 N/mm2
> 70% of Target Strength (30.275 N/mm2
)
b. 28 Days strength= 43.26 N/mm2
> 100% of Target Strength (43.25 N/mm2
)
c. Individual StrengthVariation from average value = within± 15%
8. Personal comments: Mistake, which affect the quality of Concrete
 Use of too much or too little water for mixing, or water carelessly added
during mixing.
 Incompletemixing of aggregatewith cement
 Improper grading of aggregates resulting in segregation or bleeding of
concrete.
 Inadequatecompaction of Concrete.
 Using concrete which has already begun to set.
 Placing of concrete on a dry foundation without properly wetting it with
water.
 Use of dirty aggregate or tater containing earthy matter, clay or lime.
 Leaving the finished concrete surfaceexposed to sun and wind during
the firstten days after placing without protecting it and keeping it damp
by proper methods of curing.