CONCRETE TECHNOLOGY LAB

Rajiv Gandhi University of Knowledge

Technologies Basar

LABORATORY

DEPARTMENT OF

CIVIL ENGINEERING

RGUKT BASAR

TELANGANA. -504107

List of Experiments

1. Finenessofcementtest.

2. Consistencyofcementtest.

3. Initialsettingandfinalsettingtimetest.

4. Slumpconetest.

5. VEE–BEEconsistometertest.

6. Compactionfactortest.

7. Flowtabletest.

8. Bulkingofsandtest.

9. Siltcontenttest.

10. Finenessmodulusforfineaggregateandcourse aggregate test.

11. Soundness test for cement.

12. Specificgravityof cement.

13. Compressive strength ofconcrete cube.

1.Fineness of cement test.

AIM: for a given sample of cement, determine the fineness of cement.

BACKGROUND INFORMATION:

Strengthdevelopmentofconcreteistheresultofthereactionofwaterwith

cementparticles.Thereactionalwaysstartswiththecementavailableatthe

surfaceofparticles.Thuslargerthesurfaceareaavailableforreaction,greateris

therateofhydration.Rapiddevelopmentofstrengthrequiresgreaterdegreeof

fineness.Rapidhardeningcement,therefore,requiresgreaterdegreeoffineness.

Thecementshouldbeuniformlyfine.Ifthecementisnotuniformlyfine,the

concrete made out of it will have poor workability and will required a larger

quantity of water while mixing. Also bleeding can occur i.e. even before the

concrete set water comes out of the surface due to settlement of concrete

particles.

However, too much fineness is also undesirable, because the cost of

grindingthecementtohigherfinenessisconsiderable.Finercementdeteriorates

morequicklywhenexposetoairrequiresgreateramountofgypsumforproper

retardation. Also amount of water requirement for the paste of standard

consistency isgreater.

Maynumberofparticlesshouldhavesize<100µ.Smallestparticlemay

havesizeof1.5µ.Averagesizeofparticlecanbe10µ.Particlebelow3µplays

majorroleinone-daystrength.Particlessizefrom3µto25µplaysimportantroll

in28daysstrength.Forthecommercialcement,25to30%particleshouldbeless

than7µinsize.Itis,hence,necessarytoensurecertainamountofcoarsenessin

thecement,butmaximumlimittothiscoarsenessshellbeasfollowtoobtain minimum

degree ofgrinding.

Aftersievingthecementonastandard90µI.S.testsieve,theresidueby

massshellnotexceed10%ofordinaryPortlandcement&5%forrapidhardening

cement.Therearethreemethodofcheckingfinenessofcement.

By dry sieving as describedabove,

Blaineairpermeabilitymethodand

By wetsieving.

To study method 2 and 3 reference shall be made to I.S.: 4031.

MAIN EQUIPMENTS:

1. Simple mass balance.

2. I.S. Test sieve of 90µ (I.S.400-1962).

Trowel.

Tray 30mm X30cm.

Bristlebrushwith25cmhandle

PROCEDURE:

Massaccurately100gmofcementandplaceitonastandardI.S.Sieve90µ.

Breakdownanyairsetlumpsinthesamplewithfingers,butdonotrubonthe sieve.

Continuouslysievethesamplebyholdingthesieveinbothhandsandgivinga

gentlewristmotionormechanicalsieveshakermaybeusedforthispurpose.The

sievingshouldcontinuefor15minutes.

PRECAUTION:

Thecleaningofthesieveshouldbedoneverygentlywiththehelpofabrushi.e.-

25mmor40mmbristlebrushwith25cmhandle.

After sieving, the cement must be removed from the bottom surface o sieve

gently.

Simplebalanceshouldbecheckedbeforeuse.

Sievingmustbecarriedoutcontinuously.

OBSERVATION:

Sample-I

Sample-II

Mass of cement – gms (M))

100

I.S. Sieve –Microns

90/75

Sieving time –Min

Mass Retained on sieve – gms(M1)

% Mass Retained on sieve = (M1/M) × 100

RESULTS:

Conclusion:

2.STANDARD CONSISTENCY OF CEMENT

AIM: To determine the quantity of water required to produce a

cementpaste of standardconsistency.

DEFNITION: Standard consistency is defined as that consistency which will

permit the Vicat’s plunger to penetrate to a point 5 to 7 mm from the bottom of

the Vicat mould when the cement is tested.

APPARATUS: 1. Vicat’s apparatus, Mould,Plunger.

2. Standardtrowel

3. Stopwatch.

4. Weighingbalance

DESCRIPTION:

The Vicat’s apparatus consists of a frame and a moving rod weighing 300 gm.

The plunger is kept at the lower end of the rod. It is a cylinder 10 mm.

Diameter, A pointer connected to the rod will move along with it when it is

released, over a graduated scale kept in front of it. The cement paste to be tested

is kept in the Vicat’s mould kept below the rod on a glass plate.

PROCEDURE:

1. Carefully weigh 400 gm of cement and place it on a non-poroussurface.

2. Form a crator in the centre in which add about 100 to 120 cc. ofwater.

3. Thoroughly mix the cement with water and fill, the Vicat’s mould

withthe paste.

4. The interval from the moment of adding water to the dry cement to the

moment of commencing to fill the mould is known as the time ofgauging

and shall not be less than 3 minutes and more than 5 minutes. Lower the plunger gently and

test the penetration.

1. If the penetration is between 5 to 7 mm from the bottom of the mould the

quantity of water added is the requiredconsistency.

2. Otherwise repeat the test with different percentages of water until the

required penetration is obtained. Express the amount of water as a

percentage by weight of the drycement.

OBSERVATIONS:

S. No.

Weight

Cement

Weight

of water

Reading

on scale

/ W

Standard

consistenc

CALCULATIONS: Weight of cement taken =W

Weight of water added when the plunger has a penetration

5 to 7 mm from the bottom of the mould = W

Percentage of water for standard

consistency

p = (W

/ W

) x 100

RESULT: Percentage of water for standard consistencyis

Conclusion:

3.INITIAL AND FINAL SETTING TIME OF CEMENT

AIM: To determine the initial and final setting times of cement.

APPARATUS: The Vicat’s apparatus, Needle, Annular ring, Trays, Balance

and Weights.

PROCEDURE:

1. Preparation of Test Block: Prepare a neat cement paste by gauging the

cement with 0.85 times the water required to give the paste of standard

consistency. Start a stopwatch at the instant when water is added to the

cement. Fill the Vicat’s mould with a cement paste with in three to five

minutes after addition of water. Fill the mould completely and smooth off

the surface of this paste making it level with the top of the mould. The

cement block thus prepared in the mould is testblock.

2. Clean appliances shall be used for gauging. The temperature of water and

that of the test room at the time of gauging shall be with in (27  2)

3. During the test the block shall be kept at a temperature of (27  2)

C and

at least 90% relativehumidity.

a) Determination of Initial SettingTime:

Place the test block confined in the mould and resting on the nonporous

plate, under the rod bearing the needle, lower the needle gently in contact with

the surface of the test block and quickly release, allowing it to penetrate into the

test block. In the beginning the needle will completely pierce the test block.

Repeat this procedure until the needle, when brought in contact with the test

block and released as described above, fails to pierce the block for 5 to 7 mm

measured from the bottom of the mould. The period elapsing between the time

when water is added to the cement and this time shall be initial settingtime.

b) Determination of Final SettingTime:

Replace the needle of the Vicat’s apparatus with the needle with a

circular attachment. The cement shall be considered as finally set, when upon

lowering the needle gently to the surface of the test block the needle makes an

impression there on, while the attachment fails to do so. In other words the paste

has attained such hardness that the centre needle does not pierce through the

paste more than0.5mm.

The period elapsing between the time when water is added to the cement

and the time at which the needle makes an impression on the surface on the test

block while the attachment fails to do so shall be the final setting time.

OBSERVATIONS:

INITIAL SETTING

TIME:

No.

Tim

Reading on the scale of Vicat’s apparatus

FINAL SETTING TIME:

No.

Tim

Reading on the scale of Vicat’s apparatus

RESUL

=Initial setting time ofthecement

= Final setting time ofthecement

Conclusion:

4.Slump cone test

AIM: To determine the workability of concrete mix of given proportion by

slump test.

APPARATUS: Iron Pan to mix concrete, weighing machine, trowel, slump

cone, scale and tamping rod.

DESCRIPTION: The slump cone is a hollow frustum made of thin steel sheet

with internal dimensions as, the top diameter 10cm, the bottom diameter 20 cm,

and height 30 cm .It stands on a plane non- porous surface. To facilitate vertical

lifting from molded concrete it is provided with a suitable guide attachment and

suitable foot places and handles. The tamping rod is 16mm dia 60cm long and is

bullet pointed at the lower end.

THEORY:

Unsupported concrete, when it is fresh, will flow to the sides and a

sinking in height will take place. This vertical settlement is called slump. Slump

is a measure indicating the workability of cement concrete and also slump gives

an idea of W/C ratio needed for concrete to be used for different works. Slump

increases with W/C ratio. A concrete is said to be workable if it can be easily

mixed and easily placed compacted and easilyfinished.

PROCEDURE:

Mixes are prepared with W/C. ratio 0.4, 0.5, 0.55 and 0.6. For each mix take

C.A. =10kg, F.A. =5kg and Cement = 2.5kg.

1) Mix the dry constituents to get a uniform color and then addwater.

2) The internal surface of the mould is to be thoroughly cleaned and

place on a smooth, horizontal, rigid and non-absorbentsurface.

3) Place the mixed concrete in the cleaned slump cone in 4 layers each

approximately ¼ in height of the mould . Tamp each layer 25 times

with tampingrod.

4) Remove the cone immediately, rising it slowly and carefully in the

verticaldirection.

5) As soon as the concrete settlement comes to a stop, measure the

subsidence of the concrete in mm, which gives theslump.

OBSERVATIONS:

S. No.

W/C

Ratio

Slum

Type of Slump

0.45

0.5

0.55

0.6

0.65

RESULT:

SPECIFICATIONS:

As per I.S: 456 the degree of workability is classified as follows.

Degreeofworkability Slump

Verylow 0mm to25mm

Low 25mm to50mm

Medium 50 mm to 100mm.

High 100 mm to 175mm.

Conclusion:

5.VEE–BEE consistometer test.

AIM: To find workability of concrete by Vee-Bee consistency test in terms of

Vee Bee Seconds

APPARATUS:

Vee Bee consistometer, Stopwatch, Balance, Tray, Tamping rod, measuring

jar, Weights and Trowels.

THEORY:

The consistometer is used for determining the consistency of concrete by

vibrating and transforming a concrete specimen from the shape of conical

frustum into a cylinder.

DESCRIPTION:

The consistometer consists of a

1. A vibrator table, which vibrates a rate of 3000 vibrations / min.

2. A metal pot, which holds the specimen when the concrete is vibrated. It

is secured to the vibrator table by bolts.

3. Slump cone of 300 mm high, 200 mm at the bottom and 100 mm at the

top (Open both ends).

4. Swivel arm holder: A tube, which is fixed the rear of the base of the

vibrator table. It has 4 positioning slots for swivel arm to position the metal

cone over the slump cone or Perspex disc on the specimen or to position both

of them away.

5. Swivel arms the Swivel moves freely inside the swivel arm holder. A

metal rod and a guide sleeve are fixed to the swivel arm. The graduated metal

rod passes through the guide sleeve.

6. Metal cone - this is in the form of a frustum of cone with open ends

(funnel). This is fixed to the swivel arm

7. Graduated rod

8. Tamping rod. A metal rod of 16 mm x 60 cm. long with one end bullet

ended.

PROCEDURE:

1. Position the metal cone over the slump cone. Place the concrete inside

the slump cone in 4 layers each approximately 1/4 of the height. Strokes are

applied by the rounded end of the tamping rod. Distribute the strokes in a

uniform manner over the cross section.

2. After the top layer has been rodded, position the metal cone of the swivel

arm away, and strike off the concrete, level with the top of the cone using a

trowel so that the mould is exactly filled.

3. Remove any material spilled inside the metal pot or sticking on to the

side of the slump filled.

4. Position the Perspex disc over the cone and note down the reading on the

graduated rod (L1). After keeping the disc away, lift the slump cone vertically

and remove.

5. Position the disc over the concrete. Note down the reading of the

graduated rod (L2). The difference in the readings gives the slump in

Centimeters.

6. Switch on the vibrator starting a stopwatch simultaneously. Allow the

concrete to spread out in the pot. When the whole concrete surface uniformly

adheres to the Perspex disc, stop the watch, simultaneously, switch off the

vibrator. Note down the time in seconds. Also note the reading on the

graduated rod (L3).

7. The consistency of the concrete is expressed in Vee-Bee degrees which

are

equal to the time in seconds.

8. Repeat the procedure of different W/C ratios viz.: 0.4, 0.5, 0.55, 0.6 &

0.65.

9. Draw a graph between slump in centimeters and Vee – Bee Degrees.

10. Knowing the dia of the disc and the height of the concrete after Vibration

(30+ L1 – L3), the Volume of the concrete can be computed.

Observations:

S. No.

W/C Ratio

Slump (mm)

Vee–Bee Seconds

RESULT:

SPECIFICATIONS:

INFERENCE:

6.Compaction factor test

AIM: To determine the workability of concrete mix of given proportions by compacting

factor test.

APPARATUS: Compacting factor apparatus, Balance, Weights, Trays, Tamping rod and

Trowels.

DESCRIPTION: Compacting factor apparatus consists of two conical hoppers mounted

above a cylindrical mould and fixed to a stand one above the other. The hoppers are

provided with trap doors at the bottom. The dimensions of various parts are given below.

1. Upper Hopper Dimensions in cm.

Top internal dia. 25.4

Bottom 12.7

Internal height 27.9

2. Lower Hopper Dimension in cm.

Top internal dia. 22.9

Bottom 12.7

Internal height 22.9

3. Cylinder Dimension in cm.

Internal Diameter 15.2

Internal Height 30.5

Distance between bottom of upper hopper and top of lower hopper is 20.3 cm. Distance

between bottom of lower hopper and top of cylinder is 20.3 cm.

DEFINITION:

Compacting factor is defined as the ratio of weight of partially compacted concrete to the

weight of fully compacted concrete.

PROCEDURE:

Four mixes are prepared with W/C., ratios 0.4, 0.5, 0.55, 0.6 and 0.65. For each mix take 2.5

kg of cement, 5 kg of fine aggregate and 10 kg of coarse aggregate.

1. Mix the dry constituents to get a uniform color and then add water.

2. The internal surfaces of the hoppers and cylinder are thoroughly cleaned.

3. The sample of concrete to be tested is placed gently in the upper hopper.

4. The hopper is filled level with its brim and the trap door is opened so that the concrete

falls into the lower hopper.

5. If concrete has a tendency to stick to the sides of the hopper, the concrete should be

slowly pushed down by inserting the tamping rod into the concrete.

6. Immediately after the concrete comes to door of the lower hopper, it is opened and

the concrete is allowed to fall into the cylinder.

7. The excess of concrete in the cylinder above the top is cut off and made level with

trowels. The outside of cylinder is wiped clean.

8. The weight of the concrete in the cylinder is then determined. This weight is known

as weight of partially compacted concrete.

9. The cylinder is refilled with concrete from the same sample in six layers and each is

rammed thoroughly.

10. The top of fully compacted concrete should be carefully struck off level with top

cylinder. The outside of the cylinder is wiped a clean and the weight of fully compacted

concrete is found.

OBSERVATIONs

No.

W/C

–W

C.F. =(W

–W

/ W

–W

)

CALCULATIONS:

Weight of cylinder W1 =

Weight of cylinder + partially compacted W2 =

Weight of Partially compacted concrete (W2-W1) =

Weight of cylinder + fully compacted concreteW3 = Weight of fully compacted concrete

(W3-W1) = Compacting factor (W2-W1) / (W3-W1). =

RESULTS:

Maximum workability of concrete is occurring at a water / cement ratio of

SPECIFICATIONS:

According to IS 456, the degree of workability in classified as follows:

Degree of workability Compacting factor.

Very Low 0.75 to 0.8

Low 0.8 to 0.85

Medium 0.85 to 0.92

High 0.92 & above.

GRAPH:

A graph is drawn with water / cement ratio on x-axis and values of compaction factor on y-

axis.

INFERENCE:

7.Flow table test.

Aim:

To measure the flow and workability of the concrete by using flow table

Apparatus required:

Flow table test apparatus

Procedure:

The apparatus consists of flow table about 76cm. in diameter over which concentric

circles are marked. A mould made from smooth meta

l casing in the form of a frustum of a cone is used with the following internal

dimensions. The base is 25cm. in diameter upper surface 17cm. in diameter and height

of the cone is 12cm.

1.The table top is cleaned of all gritty material and is wetted. The mould is kept on

the center of the table, firmly held and is filled in two layers.

2.Each layer is rodded 25 times with a tamping rod 1.6cm in diameter and 61cm

long rounded at the lower tamping end.

3.After the top layer is rodded evenly the excess of concrete which has overflowed

the mould is removed.

4.The mould if lifted vertically upward and the concrete stands on its own without support.

The table is then raised and dropped 12.5cm 15times in about 15 seconds.

5.The diameter of the spread concrete is measured in about 6 directions to the nearest 5mm

and the average spread is noted. The flow of concrete is the percentage increase in the

average diameter of the spread concrete over the base diameter of the mould.

6.The value could range anything from 0 to 150 per cent. A close look at the

pattern of spread of concrete can also give a good indication of the characteristics of

concrete such as tendency for segregation.

Spread diameter in cm -25

Flow, per cent = -------------------------------------x 100

Result:

The flow percent of the concrete is

Viva Voce:

Define workability of concrete?

What is the significance of flow test?

What is the water cement ratio for workable concrete?

8. Bulking of sand test.

AIM: To ascertain the bulking Phenomena of given sample of sand.

APPARATUS: Special Vessel for unit volume, tray, balance and weights,

THEORY:

Increase in volume of sand due to presence of moisture is known as Bulking of sand.

Bulking is due to the formation of thin film of water around the sand grains and the

interlocking of air in between the sand grains and the film of water.

When more water is added a sand particles got submerged and volume again becomes

equal to dry volume of sand.

To compensate the bulking effect extra sand is added in the concrete so that the ration of

coarse to fine aggregate will not change from the specified value.

Fine sands shown greater percentage of bulking than coarse sands with equal percentage of

Moisture.

PROCEDURE:

Compact the sand in three layers in the vessel, each layer being given 25 strokes, and

Strike level at top.

Weigh it and dump it into a tray. Add a certain percent of water by weight (say 2%) of

dry compacted tray.

Add a certain percent of water by weight (say 2%) of dry compacted sand.

Mix, well till uniformly moist. Fill the container with the wet sand without any tamping

strike tip surface level, and find weight of the wet loose sand.

Repeat this with moisture contents of 4,6,8,10,12,14,16,18 and 20%.

Observations

S. No.

% of

water

added

(X%)

Wt. of wet

sand W

Wt. of dry

sand in wet

sand W

gm.

= W

(1+0.01 x)

Bulk Factor

Bulking %

= (B.F-1) *

100

CALCULATIONS:

Weight of unit volume of dry compacted sand = W

Weight of loose wet

sand of unit volume = W

If moisture content be x% in sand, and if W

is weight of dry sand in W

of loose

wet sand,

Then W

+ (0.01) x W

/ (1+0.01 X).

Bulking factor (B.F.)

Bulking percentage

– W

) X 100 / W

or (B.F. –1) X 100.

GRAPH: Plot graph between B.F. on (Y- axis) and water content on (X- axis).

RESULT:

1. Moisture content at maximum bulking=

2. Percentage of maximum bulking=

SPECIFICATION:

Interface:

9. Silt content test.

Aim:To determine silt content in a given sample of fine aggregate

by sedimentationmethod.

Theory:This is a gravimetric method for determining the clay, fine silt and fine dust,

which includes particles up to 20 microns. Differences in the nature and density of

materials or in the temperature at the time of testing may vary the separation point.

Apparatus:

A watertight screw-topped glass jar of dimensions similar to a 1-kg fruit preserving jar,

A device for rotating the jar about its long axis, with this axis horizontal, at a speed of 80 ± 20

rev/min,

A sedimentation pipette, A 1 000-ml measuring cylinder, scale, well-ventilated oven, Taping

rod etc.

Chemical:

A solution containing 8 g of sodium oxalate per liter of distilled water shall be taken. For use,

this stock solution is diluted with distilled water to one tenth (that is 100 ml diluted with

distilled water to one liter).

Procedure:

1.Approximately 300 g of the sample in the air-dry condition, passing the 4.75-mm IS Sieve,

shall be weighed and placed in the screw-topped glass jar, together with 300 ml of the diluted

sodium oxalatesolution. The rubber washer and cap shall be fixed, care being taken to ensure

water tightness.

2.The jar shall then be rotated about its long axis, with this axis horizontal, at a speed

of 80 ± 20rev/min for a period of 15 minutes

3.At the end of 15 minutes, the suspension shall be poured into the 1 000-ml measuring

cylinder and the residue washed by gentle swirling and decantation of successive 150-ml

portions of sodium oxalate solution, the washings being added to the cylinder until the volume

is made up to 1000 ml.

4.The suspension in the measuring cylinder shall be thoroughly mixed by inversion and

the tube and contents immediately placed in position under the pipette.

5.The pipette A shall then be gently lowered until the tip touches the surface of the

liquid, and then lowered a further 10 cm into the liquid.

6.Three minutes after placing the tube in position, the pipette A and the bore of tap B shall be

filled by opening B and applying gentle suction at C.

7.A small surplus may be drawn up into the bulb between tap B and tube C, but this shall be

allowed to run away and any solid matter shall be washed out with distilled water from E.

8.The pipette shall then be removed from the measuring cylinder and its contents run

into a weighed container, any adherent solids being washed into the container by distilled

water from E through the tap B.

9.The contents of the container shall be dried at 100 to 110°C to constant weight, cooled and

weighed.

10.Calculations—The proportion of fine silt and clay or fine dust shall then be

calculated from the

following formula:

Percentage of Clay and Fine silt or fine dust: 100 (1000w2 _ 0.8)

W1 V

Conclusion / Result:

The clay, fine silt and fine dust content of given sample of fine aggregate is found to be ....... %

10. Fineness modulus for fine aggregate and course aggregate test.

AIM: To determine the grading of Aggregate and fineness modulus of coarse and fine

Aggregate by sieving them dry.

BACKGROUND INFORMATION:

In cement mortar, Aggregate contains 55% of volume of mortar. While in case of

mass concrete, Aggregate contains 85% of volume of concrete. Size of Aggregate used

in concrete ranges from several cms to fraction of millimeters. The maximum size actually

used varies but in any mix, particles of different sizes are incorporated, the particle' size

distribution being referred to as grading. The grading means the art of combining various

sizes of particles composing the Aggregates to produce dense and economic mixture

using minimum cement per unit volume for a given strength. The principle of grading is

that smaller particles fill up the voids between larger particles. .

Strength of concrete depends on Water/Cement ratio provided that mix is workable.

The most important factor for making concrete workable is well gradation of Aggregates.

Well-graded Aggregates mean least voids i.e. it will required minimum paste to fill up voids.

Less quantity of water and· cement is used that means it will have more strength, durability and

economy.

For the making of good quality concrete it is a common practice to use Aggregate at least in

two size groups, the main division being between fine Aggregates often called sand not larger

than 4.75 mm and coarse Aggregates, which comprises of material at least (75mm in size.

4.75mm size sieve makes the distinction between fine and coarse Aggregates.

Sieve analysis is carried out to test the grading of Aggregates. The Aggregates are sieved

successfully through the sieves. Confirming to I.S 460-1962. Sieve analysis is the operation of

dividing the sample of Aggregates into fraction, each consist the particles of the same size.

The test sieves used for concrete Aggregates have square opening and their properties are as per

I.S. 460-1962. Sieves are described by the size of opening (in mm) for larger sizes, and the

microns for sieves smaller then 1.18mm size, one micron being 10-6 meters.

All sieves are mounted in frames, which can rest. The material retained on each sieve after

shaking represents the fraction of Aggregates coarser than the sieve in question but finer than

the sieve used before 20mm diameter frame is used for 4.75mm or smaller size and 30cm to

45cm diameter frames for 4.75mm and larger sizes. 4.75 are dividing line between the fine and

coarse Aggregates.

The sieves used for concrete Aggregates consist of a series in which the clear opening in any

sieve is one half of the opening of the next larger sieve size.

Sieving can be done either manually or mechanically. In the manual operation the sieve is

shaken giving movements in all possible directions to give chance to all particles for passing.

Before the sieves analysis is performed the Aggregate sample has to be air dried in order to

avoid lumps of fine particles and to prevent clogging of finer sieves. . .

The Aggregate are sieved successfully through each sieve given in table-1 and the percentage·

by mass retained on each sieve recorded in the tabular form; Standard grading is given in table.

2 and 3 the Aggregates shall be described as belonging to any of the grading zones based on the

results obtained by the sieve analysis.

The results of sieve analysis are also to be recorded graphically, ordinate indicating percentage

passing and abscissa indicating sieve size on logarithmic scale. Logarithmic scale is used to

represent sieve of large variation in size.

Fineness modulus of coarse and fine Aggregate is also determined. Fineness modulus is defined

as the sum of the cumulative % retained on the sieves of standard series divided by 100. The

fineness modulus is an empirical factor and can be looked upon as the massed average size of a

sieve on which the material is retained, the sieves being counted from the finest. This can be

used for measuring slight variation in the Aggregate from the same sources a day-to-day check.

Smaller the value of fitness modulus finer is the sand. For good grade of concrete fitness

modulus of sand should be between 2.25-3.35 may not be satisfactory in grading. Some fraction

of particles may absent, which does not define well-graded F.A.

For high- strength & durable concrete, sand from zone I to III can be used but mix should be

properly designed. For reinforced. Concrete sand of zone IV should not be used. If course is

used in concrete, it will result in harshness, bleeding & segregation (i.e. stony mix) and if fine

sand is used in concrete, water requirement will be more & it affects durability of concrete.

Sieve analysis for coarse Aggregates shall be carried out on 9 sieves: (40 mm, 20 mm, 10 mm,

4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron and 150

micron). For fine Aggregate 6 sieves (4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron

and 150 micron) are used.

Table-1: Coarse Aggregate

I.S.

Sieve

(mm)

% passing for single size Aggregates

of normal size(mm)

% passing

from graded

Agg. Of

nominal size (mm)

100

85-100

100

0-30

85-100

100

95-100

100

0-5

0-20

85-100

30-70

95-100

0.5-20

85-100

10-35

25-55

4.75

0.5

0-20

0-5

0-10

Table-2:- Fine Aggregate: GRADING

I.S. Sieve

Percentage passing for

Grading Zone

10.00mm

100

4.75mm

90-100

2.36mm

60-95

75-100

85-100

95-100

1.18mm

30-70

55-900

55-100

90-100

600micron

15-34

35-59

60-79

80-100

300micron

5-20

8-30

12-40

15-50

150micron

0-10

0-15

For Crushed stone sand permissible % passing through 150 micron is 20%

MAIN EQUIPMENTS:

Set of sieves confirming to IS 460-1962, known quantities of coarse and fine Aggregates.

PROCEDURE:

1. Massed quantities of materials shall be taken and sieved successfully through the

specified sieves. Sieves shall be cleaned before used.

2. Each sieve shall shake separately over a clean tray for a period of not less than 2 minutes.

the shaking shall be done with motions backward and forwards, left to right, circular clockwise

and counter clockwise with frequent jarring, so that material is kept moving over solve surface.·

3. On completion of sieving the material retained over each sieve together with any

4. Material cleaned from the mesh shall be massed on a balance and recorded. .

5. The percentage by mass retained by each sieve shall be calculated and the results shall be

recorded.

6. The cumulative %is calculated.

OBSERVATIONS:

Mass of Coarse Aggregate = kg.

And Mass of fine Aggregate = kg

Sieve Size

Mass

Retained(g

Cumulative

Mass retained

(gm)

Cumulative

Massretained

Cumulative

Masspassing

Fine Aggregate:

4.75mm

2.36mm

1.18mm

600 µ(0.06mm)

300µ (0.03mm)

150µ (0.015mm)

Below 150µ`

Total

Fineness modulus =

(b)Coarse Aggregate:

40mm

20mm

12.5mm

10mm

4.75mm

2.36mm

1.18mm

600µ

300µ

150µ

Below 150µ

Total

Fineness modulus =

CURVE: Draw grading curves for both the materials on semi log graph paper.

DISCUSSION: Specified limits of fineness modulus.

Maximum size of Aggregates

Fitness Modulus

Minimum

Maximum

Fine Agg.

3.5

Coarse Agg.

20mm

6.9

40mm

6.9

7.5

80mm

7.5

8.0

150mm

8.0

8.5

It may happen that in some cases the Agg. Is not uniformly graded but still may

confirm to the specified fineness modulus. So the fineness shall be taken as a guide

only

Result:

Fine Aggregate

Coarse

Aggregate

Comment

Fineness modulus

Confirm to limits?

Grading curve confirms to

specification?

Conclusion:

11. Soundness test for cement.

AIM: Determination of soundness of cement with Le- chatelier apparatus.

REFERENCE: IS. 269-1979

BACKGROUND INFORMATION:

It is very important that cement after setting shall not undergo any appreciable change of

volume. The unsoundness of cement is caused by the undesirable expansion of some of its

constituents after setting large change in volume result in disintegration and several cracking.

The unsoundness is due to presence of free lime, magnesia and sulphate. The free lime hydrates

very slowly because it is covered by thin film of cement, which prevents directs contact between

lime and water. After setting time and moisture hydrates.

Unsoundness may reduce 6%

1. Mgo up to <0.5%

2. Fine grinding

3. Allowing the cement to acrate for several days

4. Through mixing

5. Magnesium up to 6%

Le-chatelier test for free time only but presence of magnesia cannot be indicated. It is >3%

soundness by Autoclave test.

MAIN EQUIPMENTS:

Le-chatelier apparatus, two glass plates

PROCEDURE:

1. 50 gms Of cement is weighted and quantity of water required is 0.78 time std. consistency

(0.78P) & mix it in standard manner.

2. Fill this mixture in to the mould and keep on the glass plate

3. The mould covered on the top with another glass plate.

4. The whole assembly immersed in water for 24 hrs at 27-32 degrees C temperature.

5. Measure the mould again in water, which is boiled at boiling temperature for 25- 30 min.

6. Keeps it boiling for 3 hrs.

7. Remove the mould from water and allow it to cool.

8. Measure the distance between indicator points.

OBSERVATION TABLE:

Initial

distanc

e between

indicator (mm)

(1)

Distance

between

indicator

afte

r submerging

water for 24hrs

(2)

Distance

between

indicator after

submerging in

boiling water

for 3 hrs(3)

Expansion of

cement (4) = (3)-

(2)

RESULT: The expansion of ordinary Portland cement is mm.

COCLUSION: The expansion of ordinary Portland, rapid, low heat cement should not

exceed 10 mm.

12. Specific gravity of cement.

AIM: To determine the specific gravity of cement

DEFINITION: Specific gravity of cement is defined as the ratio of weight of a given volume of

cement at a given temperature to the weight of an equal volume of distilled water at the same

temperature both weights being taken in air.

APPARATUS: Specific gravity bottle, weighing balance

MATERIAL: Kerosene free of water, naphtha having a specific gravity not less than 0.7313

shall be used in the specific gravity determination.

PROCEDURE:

1. Wt. of empty dry specific gravity bottle = W1

2. Wt. of bottle + Cement (filled 1/4 to 1/3 ) = W2

3. Wt. of bottle + Cement (Partly filled ) + Kerosene = W3

4. Wt. of bottle + Kerosene (full). = W4

5. Wt. of bottle + water (full) = W5

Specific gravity of kerosene Sk = (W4 – W1) / (W5 – W1)

(W2 –W1) x Sk

Specific gravity of Cement = --------------------------- (W4 – W1) – (W3 – W2)

RESULT: Specific Gravity of cement =

SPECIFICATIONS:

Conclusion:

13. Compressive strength of concrete cube.

AIM: To determine compressive strength for

1. M 15 conc. a) w/c = 0.55 b) w/c = 0.60 c) w/c = 0.65

2. M 20 conc. a) w/c = 0.45 b) w/c = 0.5 c) w/c = 0.55

BACKGROUND INFORMATION:

Concrete is primarily strong in compression and in actual construction. The concrete is used in

compression. Concrete, which is strong in compression, is also good in other quality. Higher the

compression strength better is the durability.

Bond strength is important in R.C.C. Compressive strength also indicated extent of control

exercised during construction. Resistance to abrasion and volume stability improves with the

compressive strength. Test for compressive strength in therefore very important in quality

control of concrete.

Preparation and conduct of compressive strength is comparatively easy and gives consistent

results than tensile strength or flexural strength. This test for determining compressive strength

of concrete has therefore assumed maximum importance.

Cylinder used is 150 mm diameter and 300 mm height. Whenever cylinders are used for

compressive strength results, the cube strength can be used to calculate with the following

formula:

Minimum cylinder strength required = 0.8 × compressive strength specified for 150 mm cube.

MAIN EQUIPMENTS:

1. Cube moulds 100 mm size and 150 mm size as per I.s.156-1959 cylinder mould 150 mm

diameter X 300 mm high as per I.s.156-1959.

2. Towels.

3. G.I. sheet for mixing.

4. Tamping rod of 16 mm diameter and 600 mm long bullet point at the lower end.

5. Glass plate thicker than 6.5 mm or machined metal plate 1.3 mm thickness and of

dimensions greater than 175 mm.

6. 100 tone compression testing machine.

PROCEDURE:

1. Fill concrete into the mould in layer approximately 50 mm deep by moving the scoop

around the top edge of the mould as the concrete slides form it, in order to ensure the

symmetrical distribution of the concrete within the mould.

2. Compaction:

If compaction is done by hand tamps the concrete with the standard rod, strokes being uniformly

distributed over the cross section of the mould. For 15cm cube, number of strokes should not be

less than 35 per layer and 25 strokes for 10cm cubes. For the cylindrical specimens, number of

strokes shall not be 30 per layer. Tamp the sides of the mould to close the voids left by tamping

bars.

3. If compaction is done by vibration then each layer is compacted· by means of a suitable

vibrating hammer or vibrator or vibrating table. Mode and quantum of vibration of laboratory

specimen shall be nearly the same as those adopted in actual operation

4. Capping:

Cylindrical specimens are capped with a thick layer of neat cement generally 2 or 3 hours after

molding operations. Caps shall be formed by Blass plate or metal plate. Work the plate on the

mould till its lower surface rests on the top of the mould. The cement for the capping shall be

mixed to a stiff plate for about 2 hours before it is to be used in order to avoid tendency of the

cap to shrink. Adhesive of the paste to the cawing to the capping plate can be avoided by

coating the plate with a thin of oil or grease.

5. Curing:

Storing the specimen in a place for 24 + 0.5 hours from time addition of water to dry

ingredients~ Remove the specimen from the mould and keep it immediately submerged in

clean, fresh water and keep them until taken out just prior to rest. Water in which the specimen

is submerged shall be renewed at every 7 days.

6. Test For Compressive Strength:

6.1. Age of test: Usually testing is done after 7 days and 28 days. The days being measured

from the time water is added to the dry ingredients.

6.2. Test at least 3 specimens at a time.

6.3. Test the specimen immediately or removal from the water and white they are still in the

wet condition. Wipe off the surface water. If the specimens are received dry. Keep them in

water for 24 hours before testing.

6.4. Note down the dimension nearest to 0.2 mm and also the mass.

7. Placing Specimen In The Machine:

7.1 Place the specimen in such a manner that the load shall be applied to opposite sides of the

cube as cast i.e. not to the top and the bottom.

7.2 Align carefully the center of the thrust of the spherica1 seated plate.

7.3 Apply load slowly and at the rate of 14 N/mm2 /min. till the cube breaks.

7.4 Note the maximum load and appearance of the concrete failure i.e. whether· Aggregates

have broken or cement paste separates from the Aggregates etc.

8. Precautions:

See that the load is applied in the center. Even a small eccentricity can cause serious deviation.

Observations:

Sr.

No.

Specimen

Concrete mix M w/c

Ratio

Identification No.

Produced on

Date

Time

Tested on

Date

Time

Age of testing

Hrs.

Measurements

Length I mm

Breath b mm

Height d mm

Area in compression

A=a × b mm

Volume

V = A × c mm

Mass of cube

) N

10.

Unit wt. ofcube

/Vkg/m

11.

Breaking load

(P)N

12.

Compressive strength

= P/A

N/mm

13.

Avg. compressive St.

= N/mm

14.

%Deviationfromavg.

value

RESULT:

Thecompressivestrengthoftheconcreteat28daysf

1.M 15 w/c= 0.55, f

2.M15w/c=0.60,f

3.M15w/c=0.65,f

4.M15w/c=0.45,f

5.M15w/c=0.50,f

6.M15w/c=0.55,f

CONCLUSION: