Lab Manual DCS

8/20/2019 Lab Manual DCS

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Design of Concrete Mix Using IS Code Method (IS: 10262-2009)

Given Data:

STIPULATIONS FOR PROPORTIONING

Grade of Concrete To be given

Type of cement OPC 43 grade conforming to IS 8112

Maximum Nominal Size of Coarse Aggregate* 20 mm

Minimum cement content 320 kg/m3

Maximum water-cement ratio 0.45

Workability 100 mm (slump)

Exposure condition Severe (for reinforced concrete)

Method of concrete placing Pumping

Degree of supervision Good

Type of aggregate Crushed angular aggregate

Maximum cement content 450 kg/m3

TEST DATA FOR MATERIALS

Specific Gravity of Cement 3.15

Chemical admixture Super plasticizer conforming to IS 9103Specific Gravity of Coarse Aggregate 2.74

Specific Gravity of Fine Aggregate 2.74

Water absorption by Coarse Aggregate 0.5%

Water absorption by Fine Aggregate 0.5%

Workability (in terms of Compaction factor) 0.95

Moisture content (Free/surface) of Fine

Aggregate

0%

Moisture content (Free/surface of Coarse

Aggregate

0%

Sieve Analysis Refer IS 10262- Page 5

* Passing by 20 mm sieve and retained by 4.75 mm sieve

STEP BY STEP PROCEDURE OF CONCRETE MIX DESIGN AS PER IS: 10262

Step – 1:

Determine the Target strength of the concrete as

s f f ck ck 65.1

where,

ck f = Required Compressive Strength of concrete at 28 daysck f = Target Compressive Strength of concrete at 28 days

s = Standard Deviation (depends on quality control) given in Table 1.

Table – 1 [ Table 1 of IS: 10262-2009]

Grade of concrete Assumed Standard

Deviation

Remarks

M 10 3.5 The values mentioned correspond to

the site control having proper storage

of cement; weigh batching of all

materials; controlled addition of

water; regular checking of all

materials; aggregate grading and

M 15 3.5

M 20 4.0

M 25 4.0

M 30 5.0

M 35 5.0


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M 40 5.0 moisture content; and periodical

checking of workability and strength.

Where there is deviation from the

above, values given in the above table

shall be increased by 1 MPa

M 45 5.0

M 50 5.0

M 55 5.0

Step 2: Selection of water-cement ratio [ Table 5 of IS: 456-2000]

Table 2:Sl.

No

Exposure Plain Concrete Reinforced concrete

Minimum

cement

content

Maximum

Free Water

ratio

Minimum

Grade of

Concrete

Minimum

cement

content

Maximum

Free Water

ratio

Minimum

Grade of

Concrete

1 Mild 220 0.60 ---- 300 0.55 M 20

2 Moderate 240 0.60 M 15 300 0.50 M 25

3 Severe 250 0.50 M 20 320 0.45 M 304 Very

Severe

260 0.45 M 20 340 0.45 M 35

5 Extreme 280 0.40 M 25 360 0.40 M 40

Adopt a water-cement ratio as 0.40

Step 3: Selection of Water Content: [ Table 2 of IS: 10262-2009]

Table 3: Maximum Water Content per Cubic Metre of Concrete for Nominal Maximum Size ofAggregate:

Nominal Maximum Size of Aggregate (mm) Maximum Water Content (kg)*

10 208

20 186

40 165* - Water Content corresponding to saturated surface dry aggregate

Maximum water content for 20 mm aggregate = 186 litre [ 25 mm - 50 mm slump]

Since the slump given is 100mm, the required water content may be established by trial or an

increase by about 3 percent for every additional 25 mm slump or alternatively by use of chemical

admixtures conforming to IS 9103 [ Page 2 of IS: 10262- 2009].

Estimated water content for 100 mm slump = 186100

6186 = 197 litre

Note: Water reducing admixtures or super plasticizing admixtures usually decrease water content

by 5 to 10 percent and 20 percent above respectively at appropriate dosages.

Based on trials with super plasticizer water content reduction of 29 percent has been achieved.

Hence, the arrived water content = 197 x 0.71 = 140 litre.

Step 4: Calculation of Cement Content:


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Water-cement ratio = 0.40

Cement content = 3/35040.0

140mkg

ratioCement Water

water of Weight

Minimum cement content as per IS-456 = 320 kg/m3

Calculated cement content > minimum cement content----> safe:

Step 5: Proportion of Volume of Coarse Aggregate and Fine Aggregate content:

Refer Table 3 of IS: 10262-2009:

Table 4: Volume of Coarse Aggregate per Unit Volume of Total Aggregate for Different Zones of

Fine Aggregate

Nominal Maximum

Size of Aggregate

(mm)

Volume of Coarse Aggregate per unit Volume of Total Aggregate for

Different Zones of Fine Aggregate*

Zone IV Zone III Zone II Zone I

10 0.50 0.48 0.46 0.44

20 0.66 0.64 0.62 0.60

40 0.75 0.73 0.71 0.69* - Volumes are based on aggregates in saturated surface dry condition

The above values are applicable for only water-cement ratio of 0.5;

Volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone I)

for water-cement ratio of 0.50 = 0.60

Table 5: Corrections for water content and sand as percentage of total aggregate

Change in condition Correction for water Correction for % of sand

For sand confirming grading Zone – I

Zone – III

Zone –

IV

–

–

–

+1.5%

-1.5%

-3.0%

Increase or decrease in value of

compaction factor by 0.1 3.0% –

Each 0.05 increase or decrease in Free

water cement ratio – 1%

For rounded aggregate -15 kg/m3 -7%

In the present case water-cement ratio is 0.40. Therefore, volume of coarse aggregate is required

to be increased to decrease the fine aggregate content.


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As the water-cement ratio is lower by 0.10, the proportion of volume of coarse aggregate is

increased by 0.02 (at the rate of -/+ 0.01 for every 0.05 change in water-cement ratio). Therefore,

corrected proportion of volume of coarse aggregate for the water-cement ratio of 0.40 = 0.62

Note: In case the coarse aggregate is not angular one, then also volume of coarse may be required

to be increased suitably, based on experience.

For pumpable concrete, these values should be reduced by 10 percent.

The volume of coarse aggregate = 0.62 x 0.90 = 0.56

Volume of fine aggregate = 1 - 0.56 = 0.44

Step 6: Final Mix Proportions:

The mix calculations per unit volume of concrete shall be as follows:

S.

No

Component Calculation

a Volume of

concrete

1 m3

b Volume of

cement

Volume of cement =

3111.01000

1

15.3

350

1000

1m

cement of gravitySpecific

cement of Mass

c Volume of water Volume of water =

3140.01000

1

1

140

1000

1m

water of gravitySpecific

water of Mass

d Volume of

chemicaladmixture

(Superplasticizer)

(@ 2.0 percent

by mass of

cementitious

material)

Volume of chemical admixture =

3006.010001

145.17

10001 m

admixtureof gravitySpecificadmixturechemical of Mass

e Volume of all in

aggregate

Volume of all in aggregate = [ a-(b+c+d)] = 1-(0.111 + 0.140 + 0.006) = 0.743

m3

f Mass of coarse

aggregate kg

aggregatecoarseof gravitySpecificaggregatecoarseof Volumee

1140100074.256.0743.0

1000

g Mass of fine

aggregate kg

aggregate fineof gravitySpecificaggregate fineof Volumee

896100074.244.0743.0

1000

Step – 7:The quantities of water, cement, coarse aggregate and fine aggregate as determine in previous steps are

for preparation of 1 m3 of concrete. Now there is a need to determine the weight of these ingredients for

desired volume. Determine required volume of concrete and consider 20% as wastage as follows:

Required volume of concrete, v = 1.2 (no. of cubes volume of each cube +


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no. of cylinders volume of each cylinder)

Step – 8:

Calculate required quantities of each ingredient for required volume as

Weight of cement for required volume of concrete = C

v

Weight of water for required volume of concrete = Ww v

Weight of Fine Aggregate for required volume of concrete = Wfav

Weight of coarse Aggregate for required volume of concrete = Wcav


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Chart for Identifying Zone of Fine Aggregate (As per IS 383: 1970)

IS Sieve

Designation

Percentage passing for

Grading Zone - I Grading Zone - II Grading Zone - III Grading Zone - IV

10 mm 100 100 100 100

4.75 mm 90-100 90-100 90-100 95-100

2.36 mm 60-95 75-100 85-100 95-100

1.18 mm 30-70 55-90 75-100 90-100

600 micron 15-34 35-59 60-69 80-100

300 micron 5-20 8-30 12-40 15-50

150 micron 0-10 0-10 0-10 0-15

Grading for Coarse Aggregate (As per IS383:1970)IS Sieve

Designation

Percentage passing for single sized aggregate of Nominal size Percentage passing for Graded aggregate of

Nominal size

63mm 40mm 20mm 16mm 12.5mm 10mm 40mm 20mm 16mm 12.5mm

80mm 100 – – – – – 100 – – –

63mm 85 –100 100 – – – – – – – –

40mm 0 –30 85 –100 100 – – – 95 – 100 100 – –


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20mm 0 – 5 0 – 20 85 – 100 100 – – 30 – 70 95 – 100 100 100

16mm – – – 85 –100 100 – – – 90 –100 –

12.5mm – – – – 85 – 100 100 – – – 90 –100

10mm 0 – 5 0 – 5 0 – 20 0 – 30 0 – 45 85 – 100 10 – 35 25 – 55 30 – 70 45 – 85

4.75mm – – 0 – 5 0 – 5 0 – 10 0 – 20 0 – 5 0 – 10 0 – 10 0 – 10

2.36mm – – – – – 0 – 5 – – – –


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9/27

Expt: No: 2

Nominal Mix For Concrete

Suitable for grade of concrete less or equal to M20

Given Data

Grade of concrete To be given

Specific gravity of cement 3.15

Specific gravity of Fine aggregate 2.65

Specific gravity of Coarse aggregate 2.65

Step 1: Determine the proportions of materials using the following Table corresponding to given

grade of concrete

Grade of

Concrete

Total quantity of dry aggregates by mass

per 50 kg of cement, to be taken as the

sum of the individual masses of fine and

coarse aggregate, kg, Max.

Proportion of fine

aggregate to coarse

aggregate (by mass)

Quantity of

water per 50 kg

of cement,

Max.

M 5 800 Generally 1:2 but

subjected to an

upper limit of 1: 1.5

and a lower limit of

1:2.5

60

M 7.5 625 45

M 10 480 34

M 15 330 32

M 20 250 30

Step 2: Determine the volume of concrete prepared using the above proportions for 50 kg of

cement.

1000

1

ca

ca

fa

fa

c

wS

W

S

W

S

C W V

where;

V = volume (m3) of concrete

C = mass of cement (kg)

Sc = specific gravity of cement,

Ww = mass of water (kg)


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Wfa = total mass of fine aggregate ( kg )

Wca = total mass of coarse aggregate

Sfa = specific gravities fine aggregate

Sca = specific gravities coarse aggregate

Step 3: Determine total volume of required concrete to fill the moulds including 20% as wastage

Required volume of concrete, v = 1.2 (no. of cubes volume of each cube +

no. of cylinders volume of each cylinder)

Step 4: Calculate required quantities of each ingredient for required volume as

Weight of cement for required volume of concrete = C(v/V)

Weight of water for required volume of concrete = Ww (v/V)

Weight of Fine Aggregate for required volume of concrete = Wfa(v/V)

Weight of coarse Aggregate for required volume of concrete = Wca(v/V)


11/27

Experiment No: 3:

Aim:

To determine the Normal consistency of cement.

What is normal/standard consistency?

The standard consistency of a cement paste is defined as that consistency which will permit the

vicat plunger to penetrate to a point 5 to 7mm from the bottom of the vicat mould.

Apparatus required:

Vicat Apparatus Conforming to IS: 5513-197 with plunger of 10 mm diameter

Balance of capacity 1Kg and sensitivity to 1gram

Gauging trowel conforming to IS: 10086-198

Experimental procedure:

Unless otherwise specified this test shall be conducted at a temperature 27 + 2 deg celcius and the

relative humidity of laboratory should be 65 + 5%.

Prepare a paste of weighed quantity of cement (300gms) with weighed quantity of potable or

distilled water, taking care that the time of gauging is not less than 3minutes nor more than

5minutes and the gauging is completed before any sign of setting occurs.

The gauging is counted from the time of adding water to the dry cement until commencing to fill

the mould.

Fill the vicat mould with this paste resting upon a non-porous plate.

Smoothen the surface of the paste, making it level with the top of the mould.

Slightly shake the mould to expel the air.

In filling the mould operators hands and the blade of the gauging trowel shall only be used.

Immediately place the test block with the non-porous resting plate, under the rod bearing the

plunger.

Lower the plunger gently to touch the surface of the test block and quickly release, allowing it sink

into the paste.

Record the depth of penetration

Prepare trial pastes with varying percentages of water and test as described above until the

plunger is 5mm to 7mm from the bottom of the vicat mould.


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Observation Table & Calculation:

Date of testing Cement

Manufacturer

Tested by Grade of

cement

Trial No. Weight of

Cement (g)

Water (cc) Water % Needle

Penetration

Remarks

1 Approximate

temperature

in the room

is _______

2

3

4

5

6

7

100tan cement of Weight

added water of Weight yConsistencdard S

Result:

The standard consistency of the cement paste is the amount of water added to cement in percentage to

the mass of dry cement. Approximate it to first decimal.

Note:

Refer IS: 4031 (Part 4) 1988 for more details


13/27

Aim:

To determine the initial setting time of cement:

Appratus:

Vicat 's needle apparatus

Balance

stop watch

Initial Setting Time of Cement:

Initial setting time is the time consumed from addition of water into dry cement to the instant at which

needle of 1 mm2

section fails to pierce the test sample to a depth of 5 mm from the bottom.

Experimental Procedure:

Sample Preparation:

Prepare a cement paste by gauging the cement with 0.85 times the water required to give a paste

of standard consistency.

Start a stop-watch, the moment water is added to the cement.

Fill the Vicat mould completely with the cement paste gauged as above, the mould resting on a

non-porous plate and smooth off the surface of the paste making it level with the top of the

mould. The cement block thus prepared in the mould is the test block.

Test Procedure:

Place the test block under the rod bearing the needle

Lower the needle gently in order to make contact with the surface of the cement paste and release

quickly, allowing it to penetrate the test block

Repeat the procedure (every two minutes for initial setting time) till the needle fails to pierce the

test block to a point 5.0 ± 0.5mm measured from the bottom of the mould

The time period elapsing between the time, water is added to the cement and the time, the needle

fails to pierce the test block by 5.0 ± 0.5mm measured from the bottom of the mould, is the initial

setting time.

Observation & Calculation:

Quantity of cement =

Normal consistency of cement in percentage (P) =


Initial setting time =

Quantity of water required = 100

85.0 cement of weight

P

Result:

The initial setting time of cement is ______________ minutes.


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Aim:

To determine the final setting time of cement

Appratus:

Vicat 's needle apparatus with annular arrangement

Balance

stop watch

Initial Setting Time of Cement:

Final setting time is the time consumed from addition of water into dry cement to the instant at which

needle of 1 mm2

with 5 mm dia attachment makes an impression on the sample but attachment fails to

make it.


Sample Preparation:

Prepare a cement paste by gauging the cement with 0.85 times the water required to give a paste

of standard consistency.

Start a stop-watch, the moment water is added to the cement.

Fill the Vicat mould completely with the cement paste gauged as above, the mould resting on a

non-porous plate and smooth off the surface of the paste making it level with the top of the

mould. The cement block thus prepared in the mould is the test block.

Test Procedure:

Place the test block under the rod bearing the needle

Bring the needle with attachment near the surface of cement and release it.

Repeat the above procedure until the needle makes an impression on surface and attachment

does not make impression.

The period elapsing between the time, water is added to the cement and the time, the needle

makes an impression on the surface of the test block, while the attachment fails to do so, is the

final setting time.



Normal consistency of cement in percentage (P) =


Initial setting time =

Final setting time =

Quantity of water required = 100

85.0 cement of weight

P

Result:


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The final setting time of cement is ______________ minutes.

Note:

For setting time of cement, refer 4031 (Part 5) – 1988.


16/27

Experiment No: 4:

Fineness of cement:

Aim:

To determine the fineness of cement

Methods of determining the fineness:

By sieving [ will be performed in the lab]

By determination of specific surface (total surface area of all the particles in one gram of cement)

by air-permeability apparatus. Expressed as cm2/gm or m2/kg. Generally Blaine Air permeability

apparatus is used.

Significance:

The fineness of cement has an important bearing on the rate of hydration and hence on the rate of gain of

strength and also on the rate of evolution of heat. Finer cement offers a greater surface area for hydrationand hence faster the development of strength.

Apparatus:

Sieve of 90 microns, balance etc.,

Procedure:

Weigh correctly 100 grams of cement and take it on a standard IS Sieve No. 9 (90 microns).

Break down the air-set lumps in the sample with fingers.

Continuously sieve the sample giving circular and vertical motion for a period of 15 minutes Mechanical sieving devices may also be used. Weigh the residue left on the sieve

This weight shall not exceed 10% for ordinary cement

Observation:

Trial No. Weight of cement taken (g) Weight of cement retained (g) Percentage of weight

retained on 90 microns

sieve

Result:

Cement is grounded well /not well as the percentage of weight retained is not greater than/greater than

10 %


17/27

Experiment No: 4:

Determination of Specific gravity of cement:

Aim:

To determine the specific gravity of cement using Le Chatelier Flask or Specific Gravity Bottle

Apparatus:

Le Chatelier Flask or Specific Gravity Bottle - 100 ml capacity

Balance capable of weighing accurately up to 0.1 grams.

Procedure:

Weigh a clean and dry Le Chatelier Flask or Specific Gravity Bottle with its stopper (W1)

Place a sample of cement upto half of the flask (about 50 grams) and weigh with its stopper (W2)

Add kerosene (polar liquid) to cement in flask till it is about half full.

Mix thoroughly with glass rod to remove entrapped air.

Continue stirring and add more kerosene till it is flush with the graduated mark.

Dry the outside and weigh (W3)

Entrapped air may be removed by vacuum pump, if available.

Empty the flask and clean it and fill clean kerosene flush with the graduated mark.

Dry the outside and weigh (W4)

Calculation:

79.0431212

W W W W

W W

cement of GravitySpecific

79.0ker

ker

ker

4

3

2

1

oseneof gravitySpecific

W osene flask of Weight

W osenecement flask of Weight

W cement flask of Weight

W flask emptyof Weight

Result:

Specific gravity of cement is _____________

Note:

Refer IS: 2720- Part 3 for more details about the test


18/27

Experiment No: 5:

Tensile strength of cement:

Aim:

To determine the tensile strengths of cement

Apparatus:

Briquette mould assembly

Balance, tension testing machine etc.,

Tensile strength of cement is the ability of cement mortar specimen to withstand the tensile load.

Procedure:

Weigh 250 grams of cement, 750 grams of sand and mix them properly.

Take (P/5 +2.5) % water of total weight of sand and cement and mix it in sand and cement, where P

is the normal consistency of cement in percentage.

Oil the interior surface of mould (which is of briquette shape)

Put the mould on table and place the whole quantity of mortar in briquette by compacting it with

tamping rod.

Put the mould at temp C 227 and relative humidity 90 % for 24 hours

At the end of this period, remove the specimens from moulds and submerge them in clean andfresh water. This water should be renewed after every week.

Take out three specimens and test them after 3 days. Similarly test 3 specimens after 7 days.


Sl. No Strength after 3 days Sl. No Strength after 7 days

1 1

2 2

3 3


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Tensile strength testing machine:

A loading Machine, double lever type, with steel scale marked from 0-500 Newtons in 10 Newton

division

Maximum loading capacity 5 kN

Automatic Loading system using Lead Shot

Lead shot 15 kg supplied with the machine. Set of weights for weighing lead shot comprising oneeach for weighing upto 0.5 kN, 1 kN, 1.5 kN & 2.0 kN

One standard Briquette Mould with Base Plate also Supplied.

Result:

Average tensile strength after 3 days =

Average tensile strength after 7 days=


20/27

Experiment No: 5:

Compressive strength of cement:

Aim:

To determine the compressive strength of cement

Apparatus:

Mould

Balance, vibrator, compression testing machine etc

Compressive strength of cement is the measure of ability of cement mortar specimens to withstand the

compressive load. It enables to distinguish rapid hardening cement from low heat and ordinary cement.

Procedure:

Weigh 185 grams of cement, 555 grams of sand and mix them properly. Take (P/4 +3) % water of total weight of sand and cement and mix it in sand and cement, where P

is the normal consistency of cement in percentage. The quantities taken are for one specimen only.

Material for each specimen should be mixed separately according to above mentioned quantities.

Oil the interior surface of mould (which is of briquette shape)

Place each mould on vibrator and fill them with cement sand mix by vibrating

Keep the moulds at temp C 227 and relative humidity 90 % for 24 hours

At the end of this period, remove the specimens from moulds and submerge them in clean and

fresh water. This water should be renewed after every week.

Take out three specimens and test them after 3 days. Similarly test 3 specimens after 7 days.


Dimensions of specimen (Cube) =

Sl. NoCompressive strength of cement =

areaSectional Cross

failureat Load

1

2

3

Result:

Average compressive strength of cement after 3 days = (MPa)

Average compressive strength of cement after 7 days = (Mpa)


21/27

Some important requirements to be met by various types of cement [ Taken from

http://www.ultratechconcrete.com/cement_types.html ]

S no Type of

cement

IS Code Fineness

m2/kg

(min)

Setting Time in

minutes

Soundness Compressive Strength in MPa

Initial

(min.)

Final

(max.)

Le

Chatelier

(mm)

Auto

Clave

(%)

3 days 7 days 28 days

1 OPC 33 269 :

1989

225 30 600 10 0.8 16 22 33

2 OPC 43 8112 :

1989

225 30 600 10 0.8 23 33 43

3 OPC 53 12269 :

1987

225 30 600 10 0.8 27 37 53

4 PPC (flyash

based)

1489 :

1991

(Part 1)

300 30 600 10 0.8 16 22 33

5 PSC (slag) 455 :

2002

225 30 600 10 0.8 16 22 33

6 SRC 12330 :

1988

225 30 600 10 0.8 10 16 33

7 White

Cement

8042 :

1989

225 30 600 10 0.8 19.8 29.7

8 RHC (Rapid

Hardening

Cement)

8041 :

1990

325 30 600 10 0.8 27 16 @ 1 day

http://www.ultratechconcrete.com/cement_types.htmlhttp://www.ultratechconcrete.com/cement_types.htmlhttp://www.ultratechconcrete.com/cement_types.html


22/27

Experiment No: 6:

Bulking of Fine aggregate [ Field Method]:

Aim:

To determine the percentage bulking of the fine aggregate

Apparatus:

Balance

Measuring cylinder, tamping rod, etc

Whenever the water is added to dry sand or it is absorbed from the atmosphere, its volume increases. This

increase in volume due to water is known as bulking of sand. It is the ratio of increase in volume to original

volume.

The volume of the fine aggregate depends largely upon its moisture content. When the fine aggregate is

moist each particle gets coated with a film of water due to surface tension. The particles are kept

separated and hence the volume apparently increases. The increase in volume is known as Bulking. The

amount of bulking increases initially with increase in water content but decrease to zero with further

increase in water content over to bulking, Fine aggregate shows completely unrealistic volume. Therefore,

it is absolutely vital that consideration must be given to the effect of bulking.

General [ As extracted from IS: 2386-Part III]:

Sand brought on to a building site or other works may contain an amount of moisture which will cause it,

when loosely filled into a container, to occupy a larger volume than it would occupy if dry. If the sand is

measure by loose volume, it is necessary in such a case to increase the measured volume of the sand, in

order that the amount of sand put into the concrete may be the amount intended for the nominal mix

used (based on dry sand). It will be necessary to increase the volume of sand by the ' percentage'

bulking. The correction to be made is only a rough approximation, because the system of measurement

by loose volume is a rough method at the best, but a correction of the right order can easily be

determined and should be applied in order to keep the concrete uniform.

Procedure:

Put sufficient quantity of the sand loosely into a container until it is about two-thirds full. Level off the top of the sand and pushing a steel rule vertically down through the sand at the

middle to the bottom, measure the height. Suppose, this is h cm.

Empty the sand out of the container into another container where none of it will be lost.

Half fill the first container with water.

Out back about the half the sand and rod it with a steel rod, about 6 mm in diameter, so that its

volume is reduced to a minimum.

The add the remainder of the sand and rod it in the same way.

Smooth and level the top surface of the inundated sand and measure its depth at the middle with

the steel rule. Suppose this is h' cms.


23/27


The percentage of bulking of the sand due to moisture shall be calculated from the formula:

1001'

h

hbulking of Percentage

Result:

The bulking should be reported to the nearest whole number.

Note:

Refer IS: 2386- Part III for more details

Experiment No: 6:

Silt content in Fine aggregate:

Aim:

To determine the percentage of silt content of the fine aggregate

Apparatus:

Balance

Measuring cylinder, tamping rod, etc


50 ml of 1 % common salt solution is placed in a 250 ml measuring cylinder.

Sand is then added to it until the level of water reaches the 100-ml mark.

More salt solution is then added to raise the level to the 150-ml mark.

With a palm placed on top of the cylinder, its contents are vigorously agitated and then allowed to

stand for 3 hours.

A distinct layer of silt appears as a top layer of sand.

The thickness of the silt layer is expressed as a percentage of the total thickness of the solid layer.

The percentage of silt should be less than 6 %.

Result:

Report the percentage of silt content and comment on the result.


24/27

Experiment No: 7:

Classification of Fine Aggregate:

Aim:

To classify the fine aggregate on the basis of sieve analysis

Apparatus:

Set of sieves

Balance


The classification of fine aggregate specified by the Indian Standards is given in Table. Grade I is the

coarsest and grade IV is the finest of the fine aggregate. For I st grade , about 90-100 percent of the

material must pass through 4.75 mm sieve and about 60-80 percent must pass through the next standard

sieve, namely 2.36 mm. The first three graded zones are usually acceptable for reinforced or prestressed

concrete constructions. However, the 4th

grade zone fine aggregate is rather too fine and will decrease

workability of the concrete.

IS SIEVE ZONE I ZONE II ZONE III ZONE IV

10 mm 100 100 100 100

4.75 mm 90-100 90-100 90-100 95-100

2.36 mm 60-95 75-100 85-100 95-100

1.18 mm 30-70 55-90 75-100 90-100

600 micron 15-34 35-59 60-79 80-100

300 micron 5-20 8-30 12-40 15-50

150 micron 0-10 0-10 0-10 0-15

Result:

Report the zone of the fine aggregate.

Note:

Refer IS: 383-1970 for more details.


25/27

Experiment No: 7:

Fineness Modulus of Fine aggregate:

Aim:

To determine the fineness modulus of fine aggregate

Apparatus:

Set of sieves

Balance


Fineness modulus: It has been observed that strength of mix is dependent wholly on the water cement

ratio while the grading of the particles is important from workability and economy point of view. The

grading of particles by Fullers formula, to get maximum density, is difficult and sometimes uneconomical to

achieve in practice. Fineness modulus method essentially is a substitute for fuller maximum density

method, aimed at standardization of the grading of aggregates. The term fineness modulus, suggested by

Abram, is a numerical index of fineness of fineness of both fine as well as coarse aggregates.

The fineness modulus is obtained by adding the percentage of the weight of materials retained on various

I.S sieves and dividing it by 100.

I.S SIEVE WEIGHT RETAINED (g) TOTAL WT RETAINED (g) PERCENTAGE WEIGHT RETAINED

40 mm 0 0 0

20 mm 0 0 0

10 mm 0 0 0

4 mm 0 0 0

2 mm 0.1 0.1 10.00

1 mm 0.25 0.35 35.00

500 micron 0.35 0.70 70.00

250 micron 0.20 0.90 90.00125 micron 0.10 1.00 100.00

Total 305.00

Fineness modulus 3.05

Result:

Fine Fineness Modulus (2.3-2.6)

Medium Fineness Modulus (2.6-2.9)

Coarse Fineness Modulus (2.9-3.2)


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Experiment No: 7:

Specific Gravity & Water Absorption of Fine aggregate:

Aim:

To determine the fineness modulus of fine aggregate

Apparatus:

Pycnometer

Balance


A sample of about 1 kg for 10 mm to 4.75 mm or 500 g if finer than 4.75 mm, shall be placed in the

tray and covered with distilled water at a temperature of 22-32 deg c. Soon after immersion, air entrapped in or bubbles on the surface of the aggregate shall be removed

by gentle agitation with a rod.

The sample shall remain immersed for 24 hours.

The water shall then be carefully drained from the sample, by decantation through a filter paper, any

material retained being returned to the sample.

The aggregate including any solid matter retained on the filter paper shall be exposed to a gentle

current of warm air to evaporate surface moisture and shall be stirred at frequent intervals to ensure

uniform drying until no free surface moisture can be seen and the material just attains a 'free-

running' condition.

Care shall be taken to ensure that this stage is not passed.

The saturated and surface dry sample shall be weighed (Weight A)

The aggregate shall then be placed in the pycnometer which shall be filled with distilled water. Any

trapped air shall be eliminated by rotating the pycnometer on its side, the hole in the apex of the

cone being covered with a finger. The pycnometer shall be topped up with distilled water to remove

any froth from the surface and so that the surface of the water in the hole is flat. The pycnometer

shall be dried on the outside and weighed (Weight B)

The contents of the pycnometer shall be emptied into the tray, care being taken to ensure that all

the aggregate is transferred.

The pyccometer shall be refilled with distilled water to the same level as before, dried on the outsideand weighed (Weight C)

The difference in the temperature of the water in the pycnometer during the first and second

weighings shall not exceed 2 deg c.

The water shall then be carefully drained from the sample by decantation through a filter paper and

any material retained returned to the sample.

The sample shall be placed in the oven in the tray at a temperature of 100 to 110 deg c for 24 hours,

during which period it shall be stirred occasionally to facilitate drying. It shall be cooled in the air-

tight container and weighed (Weight D).


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Calculations:

D

D Aweight dryof percent absorptionWater

C B D

D gravitySpecific Apparent

C B A

D gravitySpecific

)(100)(

)(

)(

A = weight of saturated surface dry sample

B = weight of pycnometer or gas jar containing sample and filled with distilled water

C = Weight of pycnometer or gas jar filled with distilled water only, and

D = Weight of oven dried sample

Result:

Report the specific gravity, apparent specific gravity and water absorption of fine aggregates and compare

with the permissible limits.

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