PUSA INSTITUTE OF TECHNOLOGY

CONCRETE TECHNOLOGY

LAB MANUAL

DIPLOMA IN CIVIL ENGINEERING

List of Experiments

1. To determine the fineness of the given sample of cement by sieving.

2. To determine the quantity of water required to produce a cement paste of standard
consistency.
3. To determine the initial and final setting time for the given sample of cement.
4. To determine the soundness of the given sample of cement by "Le Chatelier" Method.
5. To determine the compressive strength of standard cement mortar cubes compacted by
means of standard vibration machine.
6. To determine crushing value of aggregates.
7. To determine impact value of aggregates.
8. To determine abrasion value of aggregates.
9. To determine the fineness modulus of given fine and coarse aggregates.
10. To determine the specific gravity and water absorption of aggregates by perforated
basket.
11. To ascertain the bulking phenomena of given sample of sand.
12. To determine the value of Flakiness and Elongation Index of Coarse aggregates.
13. To determine the workability or consistency of concrete mix of given proportion by
slump test.
14. To determine the workability of concrete mix of given proportion by compaction factor
test.
15. To find workability of concrete by Vee-Bee consistency test in terms of Vee Bee
Seconds.
16. To determine workability of concrete by flow table test.
17. Determination of the compressive strength of cement concrete specimens.
18. Determination of the tensile strength of cement concrete specimens.
19. To assess the likely compressive strength of concrete by using rebound hammer as per IS:
13311 (Part 2) - 1992. And Ultrasonic Pulse Velocity Method IS: 13311 (Part 1) – 1992.
 Experiment: 1
FINENESS OF CEMENT
(IS: 269-1989 and IS: 4031-1988)

AIM: To determine the fineness of the given sample of cement by sieving.

APPARATUS: IS-90 micron sieve conforming to IS: 460-1965, standard balance weights,
brush.

INTRODUCTION: 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 hydration and hence the faster and greater the
development of strength. Increase in fineness of cement is also found to increase the drying
shrinkage of concrete. Fineness of cement is tested either by sieving or by determination of
specific surface by air-permeability apparatus. Specific surface is the total surface area of all
the particles in one gram of cement.

FINENESS BY SIEVING:
PROCEDURE:
1. Weigh accurately 100 g of cement and place it on a standard 90 micron IS sieve.
2. Break down any air-set lumps in the cement sample with fingers.
3. Continuously sieve the sample giving circular and vertical motion for a period of 15
minutes.
4. Weigh the residue left on the sieve. As per IS code the percentage residue should
not exceed 10% for OPC and 5% for RHC

PRECAUTIONS: Air set lumps in the cement sample are to be crushed using fingers and
not to be pressed with the sieve. Sieving shall be done holding the sieve in both hands and
with gentle wrist motion. More or less continuous rotation of the sieve shall be carried out
throughout sieving.

OBSERVATIONS:
SR NO. Weight of sample Weight of residue Fineness %
taken (gm) (gm)

RESULT: Average of fineness %

 Experiment: 2
NORMAL CONSISTENCY OF CEMENT
(IS: 269 - 1989 and IS: 4031 - 1988 (Part 4))

AIM: To determine the quantity of water required to produce a cement paste of standard
consistency.

APPARATUS: Vicat apparatus (conforming to IS: 5513 - 1976) with plunger (10 mm in
diameter) balance, weights, gauging trowel.

INTRODUCTION: 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 7 mm from the
bottom of the vicat mould. For finding out initial setting time, final setting time, soundness
of cement and compressive strength of cement, it is necessary to fix the quantity of water to
be mixed in cement in each case. This experiment is intended to find out the quantity of
water to be mixed for a given cement to give a cement paste of normal consistency and can
be done with the help of vicat apparatus.

PROCEDURE:
1. Prepare a paste of weighed quantity of cement (300 grams) with a weighed quantity
of potable or distilled water, starting with 26% water of 300g of cement.
2. Take care that the time of gauging is not less than 3 minutes, not more than 5 minutes
and the gauging shall be completed before setting occurs.
3. The gauging time shall be counted from the time of adding the water to the dry
cement until commencing to fill the mould.
4. Fill the vicat mould with this paste, the mould resting upon a non porous plate.
5. After completely filling the mould, trim off the surface of the paste, making it in
level with the top of the mould. The mould may slightly be shaken to expel the air.
6. Place the test block with the mould, together with the non-porous resting plate, under
the rod bearing the plunger (10mm diameter), lower the plunger gently to touch the
surface of the test block and quickly release, allowing it to penetrate into the paste.
7. This operation shall be carried out immediately after filling the mould.
8. Prepare trial pastes with varying percentages of water and test as described above
until the amount of water necessary for making the standard consistency as
defined above is obtained.
9. Express the amount of water as a percentage by weight of the dry cement.

PRECAUTIONS: Clean appliances shall be used for gauging. In filling the mould the
operator hands and the blade of the gauging trowel shall alone be used. The temperature of
cement, water and that of test room, at the time when the above operations are being
performed, shall be 27 + 2 C. For each repetition of the experiment fresh cement is to be
taken.
 Figure : Vicat Apparatus

OBSERVATIONS:

SR NO. Weight of Weight of Plunger Time taken Consistency of

cement (gms) water (gms) penetration cement % by
(a) (b) (mm) wt.(b/a)* 100

Result: Normal consistency for the given sample of cement is

 Experiment: 3
INITIAL AND FINAL SETTING TIME OF CEMENT
(IS: 269- 1989 and IS: 4031- 1988 part 5)

AIM: To determine the initial and final setting time for the given sample of cement.

APPARATUS: Vicat apparatus (conforming to IS: 5513-1976) with attachments,

balance, weights, gauging trowel.

INTRODUCTION: In actual construction dealing with cement, mortar or concrete, certain

time is required for mixing, transporting and placing. During this time cement paste, mortar,
or concrete should be in plastic condition. The time interval for which the cement products
remain in plastic condition is known as the setting time. Initial setting time is regarded as the
time elapsed between the moment that the water is added to the cement to the time that the
paste starts losing its plasticity. The final setting time is 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 pressure. The constituents and fineness of
cement is maintained in such a way that the concrete remains in plastic condition for certain
minimum time. Once the concrete is placed in the final position, compacted and finished it
should lose its plasticity in the earliest possible time so that it is least vulnerable to damages
from external destructive agencies. This time should not be more than 10 hours which is
referred to as final setting time. Initial setting time should not be less than 30 minutes.

PROCEDURE:
Preparation of Test Block:
1. Prepare a neat cement paste by gauging 300 grams of cement with 0.85 times the
water required to give a paste of standard consistency.
2. Potable or distilled water shall be used in preparing the paste.
3. The paste shall be gauged in the manner and under the conditions prescribed in
determination of consistency of standard cement paste.
4. Start a stop-watch at the instant when water is added to the cement.
5. Fill the mould with the cement paste gauged as above the mould resting on a
nonporous plate.
6. Fill the mould completely 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.

DETERMINATION OF INITIAL SETTING TIME:

1. Place the test blocks confined in the mould and rest it on the non-porous plate, under
the rod bearing initial setting 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.
2. In the beginning, the needle will completely pierce the test block.
3. Repeat this procedure until the needle, when brought in contact with the test block
and released as described above, fails to pierce the block to a point 5 to 7 mm
measured from the bottom of the mould shall be the initial setting time.

DETERMINATION OF FINAL SETTING TIME:

1. Replace the needle of the Vicat apparatus by the needle with an annular attachment.
 2. The cement shall be considered as finally set when, upon applying the needle gently
to the surface of the test block, the needle makes an impression there on, while the
attachment fails to do so.
3. The period elapsed between the time when water is added to the cement and the time
at which the needle makes an impression on the surface of test block while the
attachment fails to do so shall be the final setting time.

Figure : Vicat Apparatus

PRECAUTIONS: Clean appliances shall be used for gauging. All the apparatus shall be
free from vibration during the test. The temperature of water and that of the test room, at the
time of gauging shall be 27 0C + 20 C. Care shall be taken to keep the needle straight.

OBSERVATIONS:

Time in minutes
Height of mm fails in penetrate

RESULT: Initial setting time for the given sample of cement =

Final setting time for the given sample of cement =
 Experiment: 4
SOUNDNESS OF CEMENT BY LE-CHATELIER'S APPARATUS
(IS 269-1989 AND IS 4031-1988 PART 3)

AIM: To determine the soundness of the given sample of cement by "Le Chatelier" Method.

APPARATUS: Le Chatelier apparatus conforming to IS 5514-1969, Balance, Weights,

Water bath.

INTRODUCTION: It is essential that the cement concrete shall not undergo appreciable
change in volume after setting. This is ensured by limiting the quantities of free lime,
magnesia and sulphates in cement which are the causes of the change in volume known as
unsoundness. Unsoundness in cement does not come to surface for a considerable period
of time. This test is designed to accelerate the slaking process by the application of heat
and discovering the defects in a short time. Unsoundness produces cracks, distortion and
disintegration there by giving passage to water and atmospheric gases which may have
injurious effects on concrete and reinforcement.
The apparatus for conducting the test consists of small split cylinder of spring brass or other
suitable metal of 0.5mm thickness forming a mould 30 mm internal diameter and 30mm
high. On either side of the split mould are attached to indicators with pointed ends, the
distance from these ends to the center of the cylinder being 165 mm. The mould shall be kept
in good condition with the jaws not more than 50mm apart.

PROCEDURE:
1. Place the lightly oiled mould on a lightly oiled glass sheet and fill it with cement
paste formed by gauging cement with 0.78 times the water required to give a paste
of standard consistency.
2. The paste shall be gauged in the manner and under the conditions prescribed in
determination of consistency of standard cement paste, taking care to keep the
edges of the mould gently together.
3. While this operation is being performed cover the mould with another piece of glass
sheet, place a small weight on this covering glass sheet and immediately submerge
the whole assembly in water at a temperature of 27 0 - 20 C and keep there for 24
hours.
4. Measure the distance separating the indicator points.
5. Submerge the moulds again in water at the temperature prescribed above.
6. Bring the water to boiling, with the mould kept submerged for 25 to 30 minutes, and
keep it boiling for three hours.
7. Remove the mould from the water allow it to cool and measure the distance between
the indicator points. The difference between these two measurements represents the
expansion of the cement.
8. For good quality cement this expansion should not be more than 10mm.
 Figure 2: Le- Chatelier's Apparatus

OBSERVATIONS:
Initial distance between the indicator points in mm =
Final distance between the indicator points in mm =
Expansion in mm = final length - initial length =

RESULT: Expansion in mm
 Experiment: 5
COMPRESSIVE STRENGTH OF CEMENT
(IS 269-1989, IS 8112-1989, IS 12269 -1987, IS 4031-1988 (Part4) & IS: 4031-1988)

AIM: To determine the compressive strength of standard cement mortar cubes compacted by
means of standard vibration machine
.
APPARATUS: Vibration machine and cube moulds of size 7.06 cms (Conforming to IS:
4031- 1988)

STANDARD SAND: The standard sand to be used in the test shall conform to IS: 650-1991
or sand passing 100 percent through 2 mm sieve and retained 100 percent on 90 micron IS
sieve.
2mm to 1mm 33.33 percent
1mm to 500 microns 33.33 percent
500mm to 90 microns 33.33 percent.

INTRODUCTION: The compressive strength of cement mortars is determined in order to

verify whether the cement conforms to IS specifications and whether it will be able to
develop the required compressive strength of concrete. The average compressive strength of
at least three mortar cubes (area of the face 50 cm2 ) composed of one part of cement and
three parts of standard stand should satisfy IS code specifications.

PROCEDURE:
Mix proportions and mixing:
1. Clean appliances shall be used for mixing and the temperature of the water and that
of the test room at the time when the above operations are being performed shall be
27 + 2oC.
2. Place in a container a mixture of cement and standard sand in the proportion of 1:3
by weight mix it dry, with a trowel for one minute and then with water until the
mixture is of uniform color.
3. The quantity of water to be used shall be as specified below.
4. In any element, it should not take more than 4 minutes to obtain uniform colored mix.
5. If it exceeds 4 minutes the mixture shall be rejected and the operation repeated with
a fresh quantity of cement, sand and water.
6. The material for each cube shall be mixed separately and the quantity of
cement standard sand and water shall be as follows:
Cement 200 gms
Standard sand 600 grms
Water (P/4 + 3.0) percent of combined weight of cement and
sand, where p is the percentage of water required to produce a paste of
standard consistency.

MOULDING SPECIMENS:
1. In assembling the moulds ready for use, cover the joints between the halves of the
mould with a thin film of petroleum jelly and apply a similar coating of
petroleum jelly between the contact surfaces of the bottom of the mould and its
base plate in order to ensure that no water escapes during vibration.
2. Treat the interior faces of the mould with a thin coating of mould oil.
 3. Place the assembled mould on the table of the vibration machine and firmly hold it
is position by means of suitable clamps.
4. Securely attach a hopper of suitable size and shape at the top of the mould to facilitate
filling and this hopper shall not be removed until completion of the vibration period.
5. Immediately after mixing the mortar, place the mortar in the cube mould and rod with
a rod.
6. The mortar shall be rodded 20 times in about 8 seconds to ensure elimination
of entrained air and honey combing.
7. Place the remaining quantity of mortar in the hopper of the cube mould and rod
again as specified for the first layer and then compact the mortar by vibrations.
8. The period of vibration shall be two minutes at the specified speed of 12,000 +
400 vibrations per minute.
9. At the end of vibration remove the mould together with the base plate from the
machine and finish the top surface of the cube in the mould by smoothing
surface with the blade of a trowel.

CURING SPECIMEN:
1. Keep the filled moulds at a temperature of 27 + 20 C in an atmosphere of at least
90 % relative humidity for about 24 hours after completion of vibration.
2. At the end of that period remove them from the moulds.
3. Immediately submerge in clean fresh water and keep them under water until testing.
4. The water in which the cubes are submerged shall be renewed every 7 days and
shall be maintained at a temperature of 27 0C + 20C.
5. After they have been taken out and until they are tested the cubes shall not be
allowed to become dry.

TESTING:
1. Test three cubes for compressive strength at the periods mentioned under the
relevant specification for different hydraulic cements, the periods being reckoned
from the completion of vibration.
2. The compressive strength shall be the average of the strengths of three cubes for
each period of curing.
3. The cubes shall be tested on their sides without any packing between the cube and
the steel platens of the testing machine.
4. One of the platens shall be carried base and shall be self adjusting and the load shall be
steadily and uniformly applied starting from zero at a rate of 350 Kgs/Cm2/ min.
The cubes are tested at the following periods
Ordinary portland cement 3, 7 and 28 days.

CALCULATION:
Calculate the compressive strength from the crushing load and the average area over
which the load is applied. Express the results in N/mm2 to the nearest 0.05 mm2.
Compressive strength in N/mm2 = P/A =
Where P is the crushing load in N
and A is the area in mm2 (5000 mm2)
 Compressive Testing Machine Cement Cube Vibrator

PRECAUTIONS: Inside of the cube moulds should be oiled to prevent the mortar from
adhering to the sides of the mould.

RESULT: The average compressive strength of the given cement

at 3 days N/mm2
at 7 days N/mm2
at 28 days N/mm2
 Experiment:6
CRUSHING VALUE TEST
(IS : 2386 PART- IV -1963)

AIM: To determine crushing value of aggregates.

APPARATUS: IS sieves 12.5 mm, 10 mm, 2.36 mm, Cylindrical measure, 11.5 cm dia, 18
cm height, Cylindrical mould, 15.2 cm dia, 13 cm height, Compression testing machine,
Balance.

Figure 3: aggregate crushing value test setup

PROCEDURE:

The aggregate passing 12.5 mm IS sieve and retained on 10 mm IS sieve is selected

for standard test. The aggregate should be in surface dry condition before testing. The
aggregate may be dried by hearing at a temperature 100° С to 110° С for a period of 4 hours
and is tested after being cooled to room temperature.

The cylindrical measure is filled by the test sample of aggregate in three layers of
approximately equal depth, each layer being tamped 25 times by the rounded end of the
tamping rod. After the third layer is tamped, the aggregates at the top of the cylindrical
measure are leveled off by using the tamping rod as a straight edge. About 6.5 kg of
aggregate is required for preparing two test samples. The test sample thus taken is then
weighted. The same weight of the sample is taken in the repeat test.
 The cylinder of the test apparatus is placed in position on the base, one third of the
test sample is placed in this cylinder and tamped 25 times by the tamping rod Similarly, two
parts of the test specimen is added, each layer being subjected to 25 blows. The total depth of
the material in the cylinder after tamping shall however be 10 cm The surface of the
aggregates is leveled and the plunger inserted so that it rests on this surface in level position
The cylinder with the test sample and plunger in position is placed on compression machine.
Load is then applied though the plunger at a uniform rate of 4 tone per minute until the total
loads is 40 tone. Aggregates including the crushed portion are removed from the cylinder and
sieved on a 2.36 mm IS sieve. The material which passes this sieve is collected.

The above crushing test is repeated on second sample of the same weight in
accordance with above test procedure. Thus two tests are made for the same specimen
for taking an average value

IS RECOMMENDATIONS:

TABLE NO: 1

Sr. No. Crushing value Classification

1. <10% Exceptionally strong

2 >35% Weak for road surface

Table No: 2 Recommended Aggregate crushing value.

Sr. No. Description Maximum crushing value

1. Aggregate used for pavement as

30%
surface as a wearing course
2. Aggregate used for other than wearing
45%
Course

OBSERVATION TABLE

Sr. Description Test -1 Test-2

No.

1. Weight of oven drying aggregate

passing 12.5 mm IS sieve and retain on
10 mm IS sieve. W1

2. Weight of sample passes 2.36 mm IS

sieve after test W2
 3. Weight sample retain 2.36 mm IS sieve
after test W3

4. Aggregate crushing value = W2x 100

% W1

5. W1=W2+ W3

6. Avg. aggregate crushing value

Total weight of dry sample taken = W1 g

Weight of the portion of crushed material passing 2.36 mm IS sieve = W2 gr.

The aggregate crushing value is defined as a ratio of the weight of fines passing the specified
IS sieve to the total weight of the sample. Expressed as a percentage The value is usually
recorded up to the first decimal place.

Aggregate crushing value = 100 × W2

W1

RESULTS:

The mean of the crushing value obtained in the two tests is reported as the aggregate crushing
value.

CONCLUSION
 Experiment: 7
IMPACT VALUE TEST
(IS: 383- 1970)

AIM: To determine impact value of aggregates.

INTRODUCTION:
Toughness is the property of a material to resist impact. Due to traffic loads the road
stone are subjected to the pounding action of impact and there is possibility of breaking into
smaller pieces. The road stone should therefore be tough enough to resists fracture under
impact. A test designed to evaluate the toughness of stones i.e. the resistance of the stones to
fracture under repeated impacts may be called an impact test for road stones.
The aggregate impact value indicates a relative measure of the resistance of an
aggregate to a sudden shock or an impact, which differs from its resistance to a slow
gradually increasing compressive load. The method of test covers the procedure for
determining the aggregate impact value of course aggregate.
APPARATUS:
The apparatus consists of an impact testing machine, a cylindrical measure, tamping
rods, IS sieves, balance and oven.
 Impact Testing Machine :
The machine consists of a metal base with a plan lower surface, supported well on
firm floor, without rocking. A detachable cylindrical steel cup of internal diameter 10.2 cm
and depth 5 cm is rigidly fastened centrally to the base plate A metal hammer cylindrical m
shape, 10 cm in diameter and 5 cm long, with 2 mm chamber at the lower edge is capable of
sliding freely between vertical guides, and fall concentric over the cup. There is an
arrangement for raising the hammer and allowing is to fall freely between vertical guides
from a height of 38 cm on the test sample in the cup, the height of fall being adjustable upto
0.5. A key is provided for supporting the hammer while fastening or removing the cup. Refer
Figure.
 Measure:
A cylindrical metal measure having internal diameter 7.5 cm and depth 5 cm for
measuring aggregate.
 Tamping Rod :
A straight metal temping rod of circular cross section 1 cm diameter and 25 cm long,
rounded at one end.

 Sieve:
IS sieve of sizes 12.5 mm, 10 mm, and 2.36 mm for sieving the aggregates
 Oven:
A thermostatically controlled drying oven capable of maintaining constant
temperature between 100° C and 110° C.
 Balance:
A balance of capacity not less than 500 gm to weight accurate to 0.1 gm

Figure 4: Aggregate Impact Testing Machine

SAMPLE QUANTITY:
The test sample shall consist of aggregate passing through 12.5 mm IS sieve and
retained on a 10 mm IS sieve.
The metal measure shall be filled about one third full with the aggregate and tamped
with 23 stocks of the rounded and of the tamping rod A further similar quantity of aggregate
shall be added and procedure repeated. The measure shall finally be filled to overflowing
capacity and after tamping surface material is struck off using temping rod weight of aggregate
in the measure is determined and same weight is taken for duplicate test.

PROCEDURE:
The test sample consists of aggregates passing 12.5 mm sieve and retained on 10
mm sieve and dried in an oven for four hours at a temperature 100° C to 110° C, and cooled.
Test aggregates are filled up to about one third full in the cylindrical measure and tamped 25
times with rounded end of the tamping rod. Further, quantity of aggregates m then added
upto about two third full m the cylinder and 25 stroked of the tamping rod are given. The
measure is now filled with the aggregates to over flow, tamped 25 times.
The surplus aggregates are struck off using the tamping rod as straight edge. The net
weight of the aggregates in the measure is determined to the nearest gram and this weight
off the aggregates is used for earning out duplicate test on the same material.

The Impact machine is placed with its bottom plate flat on the floor so that the
hammer guides columns are vertical. The cup is fixed firmly in position of the base of the
machine and the whole of the test sample from the cylindrical measure is transferred to the
cup and compacted by tamping rod with 25 strokes.

The hammer is raised until its lower face is 38 cm above the upper surface of the
aggregates in the cup, and allowed to fall freely on the aggregates. The test sample is
subjected to a total of 15 such blows, each being delivered at an interval of not less than one
second. The crushed aggregates are than removed from the cup and the whole of its sieved
on the 2.36 mm sieve until on further significant amount passes. The fraction passing the
sieve is weighted accurate to 0.1 g. The fraction weight of the fractions passing and retained
on the sieve is added is should not be less than the original weight of the specimen by more
than one gram, if the total weight is less than original by over one gram the result should be
discarded and a fresh test made.

The above test is repeated on fresh aggregate sample.

OBSERVATIONS:
TABLE NO : 1 Aggregate observation Table
Sr. Description Sample - I Sample –
No. II
1. Original weight of the aggregate passing through
12.5 mm IS sieve and retained on 10 mm IS sieve
i.e. weight ->W1
2. Weight of the aggregate passing through 2.36
mm IS sieve after the test
i.e. weight -> W2
3. Weight of the aggregate retained on 2.36 mm IS
sieve after the test
i.e. weight ->W3 = W1 - W2
4. W2+ W3
5. Impact Value = W 2 x 100%
W1
Aggregate Impact Value = _______ % =
 SPECIFICATIONS:
Table no : 2 (Aggregate Impact Values)

Sr. Aggregate Impact Value Type of aggregate

No.
1. Up to 10 % Exceptionally strong
2. 10% to 20% Strong
3. 20% to 30% Satisfactory for road surface
4 >35% Weak for road surface

CALCULATIONS:
The aggregate impact value is expressed as the percentage of the fines formed in
terms of the weight of sample.
Let the original weight of the oven dry sample be = W1, g and the weight of
fraction passing 2.36 mm IS sieve be W2 g.
Aggregate impact value = W2 ×100 %
W1
CONCLUSION:
 Experiment: 8
ABRASION VALUE TEST
(IS 2386 PART-IV -1963)
AIM: To determine abrasion value of aggregates.

LOS ANGELES ABRASION TEST:

The principle of Los Angeles Abrasion Test is to find the percentage wear due to the
relative rubbing action between the aggregate and steel balls used as abrasive charge,
pounding action of these balls also exist while conducting the lest. Some investigators
believe this test to be more dependable as rubbing and pounding action simulate the field
conditions where both abrasion and impact occur. Los Angeles Abrasion Test has been
standardized by the ASTM, AASHO and also by the ISI Standard specifications of Los
Angeles Abrasion Values are also available for various types of pavement constructions.

APPARATUS:
(i). Los Angeles Machine should have essential characteristics as under: The machine
has hollow steel cylinder 700 mm in dia, and 500 mm in side length. A steel self 88
x 25 x 500 mm is projecting radially. It can be mounted on inside of the cover plate.
(ii). Sieve 1.70 mm and as given in Table 1. for different grades of aggregates
(iii). Abrasive charge: It consists of cast iron spheres or steel sphere app 48 mm in dia and
weighing 390 to 446 gm No of spheres are chosen from Table - 2 as per the grade of
aggregates.
(iv). Oven and accurate balance.

Figure 5: Loss Angeles Abrasion Testing Machine

SAMPLE QUANTITY:
Sieve the sample of aggregate and refer to the "Grades of Test sample" to decide the
grade and the weight of the aggregate to be taken. Take little пюге than the required quantity
and pH it in the oven at 105 °C to 110 °C for 24 hours for drying. Allow it to cool to room
temperature. From this sample, weigh the required quantity for the test

PROCEDURE:

Clean aggregate dried in oven at 105° С to 110 °C to constant weight, confirming to

any one of the grading A, to G, as per Table 1 is used for the test. The grading or grading
used in the test should be nearest to the grading to be used in construction Aggregates
weighing 5 kg for grading А, В, С or D and 10 kg for grading E, F or G may be taken as test
specimen and placed in the cylinder. The abrasive charge is also chosen in accordance with
Table 1 depending on the grading of the aggregate and is placed m the cylinder of the
machine. The cover is then fixed dust sight. The machine is rotated at a speed of 30 to 33
revolutions per minute. The machine is rotated for 500 revolutions for grading А, В, С and D.
For grading E, F and G, it shall be rotated for 1000 revolutions. The machine should be
balanced and driven in such a way as to maintain uniform peripheral speed.

After the desired number of revolutions, the machine is stopped and the material is
discharged from the machine taking care to take out entire stone dust. Using a sieve coarser than
1 70 mm IS sieve, the material is first separate into two parts and the finer portion is taken out
and sieved further on a 1.7 mm IS sieve. The portion of material coarser than 1.70
mm size is washed and dried in an oven at 105 °C to 110 °C to constant weight and correct to
one gram

OBSERVATION TABLE :

Sr.
Description Sample -1 Sample - II
No.

1. Original weight of aggregate W1

gms.
Weight of material retain on 1.70
2.
mm IS-sieve after test W2
3. Weight of passing (W1 - W2)
gms.
Abrasion Value in % =
4. W1 - W2 x100
W1
5 Avg. Abrasion value in %
APPLICATIONS OF LOS ANGELES ABRASION TEST :

Los Angeles Abrasion test is very widely accepted as suitable test to asses the hardness of
aggregate used in pavement construction. Many agencies have specified the desirable limits
of the test, for different methods of pavement construction. The maximum allowable Los
Angeles Abrasion values of aggregates as specified by Indian Roads Congress for different
methods of construction are given below:
Sr. Type of surface Max. Los Angeles
No. Abrasion Value %
1. Water Bound Macadam and surface treated 40
WBM (Wear at 500 revolutions)
2. Bituminous surface dressing – BM 40
3. Bituminous dam macadam 35
4. DBM,SDBC 35
5. Bituminous concrete 30
6. Cement Concrete 16

The difference between the original and final weights of the sample expressed as a
percentage of the original weight of the sample is reported as the percentage wears.

TABLE : 1 (Specification for Los Angeles Test)

Grad Weight in grams of each lest sample in the size range mm No. of Weight of
-ing (passing and retained on square holes) spheres charge
gms.
80-63 63-50 50-40, 25-20 20- 12.5- 10- 6.3- 4.75-
40-25 12.5 10 6.3 4.75 2.36
A - - - 1250 1250 1250 1250 - - - 12 5000±25
В - - - - - 2500 2500 - - - 11 4584±25
С - - - - - - - 2500 2500 - 8 3330±20
D - - - - - - - - - 5000 6 2500+15
E 2500' 2500 5000 - - - - - - - 12 5000+25
»
F - - 5000 5000 - - - - - 12 5000±25
" *
G - - - 5000 5000 - 1- - - 12 5000+25
*

 Tolerance of ±2 percent is permitted

 Let the original weight of aggregate = W1 gm
 Weight of aggregate retained on 1.70 mm IS sieve after the test = W2 gm
 Loss in weight due to wear = (Wl- W2) gm
  Percentage wear = (W1-W2)/ Wl * 100%
CALCULATION:

OBSERVATIONS AND CALCULATIONS:

1 Original Wt Of aggregate, W1 = _________ gms

2 Weight of material retained

1.7 mm IS Sieve after test, W2 = _________ gms.

3. Weight of passing, W1 -W2 = _________ gms.

4 Abrasion value in % = W 1 -W2 x 100 = %

W1

RESULT:
Average Abrasion value in % =

CONCLUSION:
 Experiment: 9
FINENESS MODULUS OF FINE AND COARSE AGGREGATE
(IS: 2386 PART – I – 1963)

AIM: To determine the fineness modulus of given fine and coarse aggregates.

APPARATUS: IS test sieves, square hole perforated plate 75mm, 40mm, 20mm, 10mm, and
fine wire cloth of 4800, 2400, 1200, 600, 300, and 150 Microns. Weighing balance
(Sensitivity 0.1 percent) sieve shaker, tray plates.

INTRODUCTION: Fine aggregate is sand used in mortars. Coarse aggregate is broken

stone used in concrete. The size of the fine aggregate is limited to maximum 4.75 mm
(4800 microns) beyond which it is known as coarse aggregate. Fineness modulus is only a
numerical index of fineness, giving some idea about, the mean size of the particles in the
entire body of concrete.

Determination of fineness modulus is considered as a method of standardization of grading of

aggregates i.e. the main object of finding fineness modulus is to grade the given aggregate for
the most economical mix and workability with minimum quantity of cement. It is obtained by
sieving known weight of given aggregate in a set of standard sieves and by adding the
percent weight of material retained on all the sieves and dividing the total percentage by 100.

PROCEDURE:
Coarse aggregate:
1. Take 5Kgs of coarse aggregate (nominal size 20mm) from the sample by quartering.
2. Carry out sieving by hand, shake each sieve in order 75mm ,40mm, 20mm, 10mm,
and No's 480, 240, 120, 60, 30, & 15 over a clean dry tray for a period of not less
than 2 minutes.
3. The shaking is done with a varied motion backward and forward, left to right,
circular, clockwise and anticlockwise and with frequent jarring.
4. So that material is kept moving over the sieve surface in frequently changing
directions.
5. Find the weight retained on each sieve taken in order

Fine aggregate:
1. Take 1 Kg of sand from sample by quartering in clean dry plate.
2. Arrange the sieves in order of No. 480, 240, 120, 60, 30 and 15 keeping sieve 480 at
top and 15 at bottom.
3. Fix them in the sieve shaking machine with the pan at the bottom and cover at the top.
4. Keep the sand in the top sieve no 480, carry out the sieving in the set of sieves and
arranged before for not less than 10 minutes.
5. Find the weight retained in each sieve.
OBSERVATIONS:
Coarse aggregate: Wt. of coarse aggregate taken: Kgs.

SR no Sieve size Weight % Weight % Weight Cumulative

retained retained passing % Weight
retained
1 40 mm
2 20 mm
3 10 mm
4 4.75 mm
5 2.36 mm
6 1.18 mm
7 600 micron
8 300 micron
9 150 micron

Fine aggregate: Wt. of fine aggregate taken: Kgs

SR no Sieve size Weight % Weight % Weight Cumulative

retained retained passing % Weight
retained
1 4.75 mm
2 2.36mm
3 1.18 mm
4 600 micron
5 300 micron
6 150 micron

Fineness Modulus: Sum of Cumulative percentage Wt. retained /100

PRECAUTIONS:
1. The sample should be taken by quartering.
2. The sieving must be done carefully to prevent the spilling of aggregate.

RESULT:
The fineness modulus of given fine aggregate:
The fineness modulus of given coarse aggregate:
 Experiment: 10
SPECIFIC GRAVITY AND WATER ABSORPTION TEST
(IS: 2386 PART -3)
AIM: To determine the specific gravity and water absorption of aggregates by perforated
basket.

INTRODUCTION:

The specific gravity of an aggregate is considered to be a measure of strength or

quality of the material. The specific gravity test helps in the identification of stone. Water
absorption gives an idea of strength of aggregate. Aggregates having more water absorption
are more porous in nature and are generally considered unsuitable unless they are found to
be acceptable based on strength, impact and hardness tests.

1) Specific gravity = (dry weight of the aggregate / Weight of equal volume of water)

2) Apparent specific gravity = (dry weight of the aggregate / Weight of equal volume
of water excluding air voids in aggregate)

APPARATUS:

 A wire basket of not more than 6.3mm mesh or a perforated container of convenient
 size with thin wire hangers for suspending it from the balance.
  A thermostatically controlled oven to maintain temperature of 100° to 110°C.
  A container for filling water and suspending the basket.
  An airtight container of capacity similar to that of the basket.
 A balance of capacity about 5 kg. to weigh accurate to 0.5 g. and of such a type and
 shape as to permit weighing of the sample container when suspended in water.
 A shallow tray and two dry absorbent clothes, each not less than 750 X 450 mm.

PROCEDURE:

(i) About 2 kg of aggregate sample is washed thoroughly to remove fines, drained and placed
in wire basket and immersed in distilled water at a temperature between 22- 32º C and a
cover of at least 5cm of water above the top of basket.

(ii) Immediately after immersion the entrapped air is removed from the sample by lifting the
basket containing it 25 mm above the base of the tank and allowing it to drop at the rate of
about one drop per second. The basket and aggregate should remain completely immersed
in water for a period of 24 hour afterwards.
(iii) The basket and the sample are weighed while suspended in water at a temperature of 22°
– 32°C. The weight while suspended in water is noted =W1g.

(iv) The basket and aggregates are removed from water and allowed to drain for a few
minutes, after which the aggregates are transferred to the dry absorbent clothes. The empty
basket is then returned to the tank of water jolted 25 times and weighed in water= W2g.

(v) The aggregates placed on the absorbent clothes are surface dried till no further
moisture could be removed by this cloth. Then the aggregates are transferred to the second
dry cloth spread in single layer and allowed to dry for at least 10 minutes until the
aggregates are completely surface dry. The surface dried aggregate is then weighed =W3 g

(vi)The aggregate is placed in a shallow tray and kept in an oven maintained at a

temperature of 110° C for 24 hrs. It is then removed from the oven, cooled in an air tight
container and weighted=W4 g.

OBSERVATIONS:

1) Empty weight of pycnometer = W1 gm

2) Weight of pycnometer + Dry aggregate= W2 gm
3) Weight of pycnometer + Dry aggregate + Water = W3 gm
4) Weight of pycnometer + Water = W4 gm

CALCULATION:

1) Specific gravity = W 2 – W 1 ______

(W2 – W1) -- (W3 – W4)
FOR WATER ABSORPTION:

1) Dry weight of aggregate = W1 =

2) Weight of aggregate immersed in water = W2 =
3) Water absorption = W2 – W1 X 100 =
W1

RESULT:

CONCLUSION:
 Experiment: 11
BULKING OF SAND

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

APPARATUS: 1000ml measuring jar, brush.

INTRODUCTION: 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 sand particles get 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 ratio of
coarse to fine aggregate will not change from the specified value. Maximum increase in
volume may be 20 % to 40 % when moisture content is 5 % to 10 % by weight. Fine sands
show greater percentage of bulking than coarse sands with equal percentage of moisture.

PROCEDURE:
1. Take 1000ml measuring jar.
2. Fill it with loose dry sand upto 500ml without tamping at any stage of filling.
3. Then pour that sand on a pan and mix it thoroughly with water whose volume
is equal to 2% of that of dry loose sand.
4. Fill the wet loose sand in the container and find the volume of the sand which is in
excess of the dry volume of the sand.
5. Repeat the procedure for moisture content of 4%, 6%, 8%, etc. and note down the
readings.
6. Continue the procedure till the sand gets completely saturated i.e till it reaches the
original volume of 500 ml.

OBSERVATIONS:

SR NO Volume of dry % of moisture Volume of wet % of bulking

loose sand V1 content added loose sand V2 V2- V1/ V1
1 500 ml 2%
2 4%
3 6%
4 8%

GRAPH: Draw a graph between percentage moisture content on X-axis and percentage
bulking on Y-axis. The points on the graph should be added as a smooth curve. Then from
the graph, determine maximum percentage of bulking and the corresponding moisture
content.

PRECAUTIONS:
1. While mixing water with sand grains, mixing should be thorough and uniform.
2. The sample should not be compressed while being filled in jar.
3. The sample must be slowly and gradually poured into measuring jar from its top.
4. Increase in volume of sand due to bulking should be measured accurately.
RESULT: The maximum bulking of the given sand is -----------at -----------% of moisture
content.
 Experiment: 12
FLAKINESS AND ELONGATION INDEX
(IS: 2386 PART -1)

AIM: To determine the value of Flakiness and Elongation Index of Coarse aggregates.

INTRODUCTION:
The particle shape of aggregates is determined by the percentages of flaky and
elongated particles contained in it. In the case of gravel it is determined by its angularity
number. For base course and construction of bituminous and cement concrete types, the
presence of flaky and elongated particles are considered undesirable as they may cause
inherent weakness with possibilities of breaking down under heavy loads. Rounded
aggregates are preferred in cement concrete road construction as the workability of concrete
improves. Angular shape of particles are desirable for granular base course due to increased
stability derived from the better interlocking. Thus evaluation of shape of the particles,
particularly with reference to flakiness, elongation of angularity is necessary.

FLAKINESS INDEX:

The flakiness index of aggregates is the percentage by weight of particles whose

least dimension (thickness) is less than three fifths (0.6) of their mean dimension The test is
not applicable to sizes smaller than 6.3 mm.

APPARATUS:

The apparatus consists of a standard thickness gauge shown in fig. 1. IS sieves of

sizes 63, 50, 40, 31.5, 25, 20, 16, 12.5, 10 and 6.3 mm and a balance to weigh the samples.

PROCEDURE:

The sample is sieved with the sieves mentioned in table 1 A Minimum of 200 pieces
of each fraction to be tested are taken and weighted = W, g. in order to separate flaky
materials, each fraction is then gauged for thickness on a thickness gauges shown in fig.6 or
in bulk on sieves having elongated slots. The width of the slot used should be of the
dimensions specified in column (3) of Table 1 for the appropriate size of material. The
amount of flaky material passing the gauge is weighted to an accuracy of at least 0.1 percent
of the test sample.

CALCULATION AND RESULTS:

In order to calculate the flakiness index of the entire sample of aggregates first the
weight of each fraction of aggregate passing and retained on the specified set of sieves is
noted. As an example let 200 pieces of the aggregate passing 50 mm sieve and retained on 40
mm sieve be = W, g. Each of the particle for this fraction of aggregate is tried to be passed
through the slot of the specified thickness, in this example, the 27 mm thickness gauge.Let
the weight of the retained the specified sieves. W,, W2, W3 etc. are weighted and the total
weight W1 + W2 + W3 +Wg is found. Then the flakiness index is the total weight of the
material passing the various thickness gauges, express as a percentage of the total weight of
the sample gauged.

Figure 6: Thickness Gauge

Figure 7: Length Gauge

(B) ELONGATION INDEX:

The elongation index of an aggregate is the percentage by weight of particles whose greatest
dimension (length) is greater than one and fifth times (1.8 times) their mean dimension. The
elongation test is not applicable to sizes smaller than 6.3 mm

APPARATUS:

The apparatus consists of the length gauge shown in fig 7. sieve of the sizes specified in
table 1 and a balance.

PROCEDURE:

The sample is sieved through the IS sieve specified in Table 1. A minimum of 200 pieces of
each fraction is taken and weighted In order to separate elongated material, each fraction is then
gauged individually for length in a length gauge (See fig 5.2). The gauge lengths used should be
those specified in column 4 of Table 1 for the appropriate material. The pieces of aggregates from
each fraction tested which could not pass through the specified gauge length with its long side are
collected separately to find the total weight of aggregates retained on the gauge from each fraction.
The total amount of elongated material by the length gauge is to an accuracy of at least 0.1 percent
of the weight of the test sample.

CALCULATIONS AND RESULTS:

In order to calculate the elongation index of the entire sample of aggregates the weight of
aggregate which is retained on the specified gauge length from each fraction is noted As an example
let 200 pieces of the aggregate passing 40 mm sieve and retained 25 mm sieve weight W, g. Each
piece of these are tried to be passed through the specified gauge length of 58.5 mm with its longest
size and which do not pass the gauge are separated and the total weight determined W1 g. Similarly
the weight of each fraction of aggregate passing and retained on specify sieve sizes are found Wl,
W2, W3 .......... and the total weight of sample determined = W1 + W2 + W3 .........= Wg Also
the weight of material form each fraction retained on the spec med gauge length are found = X1, X2,
X3.........and the total weight retained determined = X1 + X2 + X3.............=Xg
The elongation index is the total weight of the material retained on the various length gauges,
expressed as a percentages of the total weight of the sample gauged.

(X1 + X2 + X3 +…)100
Elongation Index= _________________________ × 100 %

W1 + W2 + W3+..

= 100 X %
W

OBSERVATION TABLE :

Weight of the Aggregate taken for the test (W) = _______________gms

 FLAKINESS INDEX ELONGATION INDEX
Passing Retained on Weight of Weight of Weight of Weight of
through IS IS sieve Aggregate aggregate in Non- Flaky the
Sr. sieve (mm) taken in each each fraction Aggregate aggregate in
fraction
No. (mm) (gms) passing the taken each each fraction
thickness fraction (gms) not passing
Gauge (gms) the length
Gauge (gms)
1 50 40
2 40 25
3 25 20
4 20 16
5 16 12.5
6 12.5 10
7 10 6.3
W= w= W1 = w1 =
(w/W)x100 = (w1/ W1)x100 =
Combined Index:
Flakiness Index:
Elongation Index:

CALCULATION:

RESULT:

CONCLUSION:
 Experiment: 13

SLUMP TEST
AIM: To determine the workability or consistency of concrete mix of given proportion by slump
test.

APPARATUS: Iron pan to mix concrete, weighing machine, trowel slump, cone, scale and
tamping rod. The slump cone is a hollow frustum made of thin steel sheet with internal
dimensions, as the top diameter 10 cms. The bottom diameter 20 cms, and height 30cms. It
stands on a plane nonporous surface. To facilitate vertical lifting from moulded concrete it is
provided with a suitable guide attachment and suitable foot pieces and handles. The tamping rod
is 16mm. dia. 60 cm. long and is bullet pointed at the lower end.

PROCEDURE: 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 measu6, 0.7 and
0.8. For each mix take 10 Kg. C.A., 5 Kg., FA and 2.5 Kg. Cement.
1. Mix the dry constituents thoroughly to get a uniform colour and then add water.
2. The internal surface of the mould is to be thoroughly cleaned and placed on a smooth,
horizontal, rigid and non absorbent surface.
3. Place the mixed concrete in the cleaned slump cone in 4 layers each approximately 1/4 in
height of the mould. Tamp each layer 25 times with tamping rod.
4. Remove the cone immediately, rising it slowly and carefully in the vertical direction.
5. As soon as the concrete settlement comes to a stop, measure the subsistence of the
concrete in cms, which gives the slump.

Note: Slump test is adopted in the Laboratory or during the progress of the work in the field for
determining consistency of concrete where nominal max., size of aggregates does not exceed 40
mm. Any slump specimen which collapses or shears off laterally gives incorrect results and at
this juncture the test is repeated only true slump should be measured.

OBSERVATIONS:

SR No w/c ratio Slump in mm

1 0.5
2 0.6
3 0.7
4 0.8

PRECAUTIONS:
1. The strokes are to be uniformly applied through the entire area of the concrete section.
2. The cone should be removed very slowly by lifting it upwards without disturbing
the concrete.
3. During filling the mould must be firmly pressed against the base.
4. Vibrations from nearly machinery might also increase subsidence; hence test should be
made beyond the range of ground vibrations.
COMMENTS: This test is not a true guide to workability. For example, a harsh coarse mix
cannot be said to have same workability as one with a large portion of sand even though they
have the same slump.
Recommended slumps of concrete mix of various works

SR NO Description of work Recommended slump in cms

1 Road work 2.5 to 5.0
2 Ordinary beams to slabs 5 to 10
3 Columns thin vertical section & retaining Walls etc 7.5 to 12.5
4 Mass concrete(Runway, Pavements) 2.5 to 5
 Experiment: 14
COMPACTION FACTOR TEST
(IS 5515 - 1983)

AIM: To determine the workability of concrete mix of given proportion by compaction factor
test.

APPARATUS: Compaction factor apparatus, trowel weighing machine conical hoppers

mounted vertically above the cylindrical mould. The upper mould has internal dimensions as top
dia 25 cm bottom dia 12.5 cm and height 22.5 cm. The lower hopper has internal dimensions, top
22.5cm bottom dia 12.5cm and height 22.5cm. The cylinder has internal dimensions as 15 cm dia
and 30cm height. The dimensions between bottom of the upper hopper and top of the lower
hopper, bottom of the lower hopper and top of cylinder are 20 cm, each case. The lower ends of
the hoppers are filled with quick release trap doors.

THEORY: This test is adopted to determine workability of concrete where nominal size of
aggregate does not exceed 40 mm. It is based on the definition, that workability is that property
of concrete, which determines the amount of work required to produce full compaction.
The test consists essentially of applying a standard amount of work to standard quantity of
concrete and measuring the resulting compaction.
The compaction factor is defined as the ratio of the weight of partially compacted concrete to
the weight of fully compacted concrete. It shall be stated to the nearest second decimal place.

PROCEDURE: Conduct test for W/c ratio 0.5, 0.6, 0.7, and 0.8, for each mix take 10 kg
of coarse aggregate 5kg of fine aggregate and 2.5 Kg of cement.
1. Grease the inner surface of the hoppers and the cylinder.
2. Fasten the hopper doors.
3. Weigh the empty cylinder accurately (Wt. Kgs).
4. Fix the cylinder on the base with fly nuts and bolts
5. Mix coarse and fine aggregates and cement dry until the mixture is uniform in colour
and then with water until concrete appears to be homogeneous.
6. Fill the freshly mixed concrete in upper hopper gently with trowel without compacting.
7. Release the trap door of the upper hopper and allow the concrete of fall into the lower
hopper bringing the concrete into standard compaction.
8. Immediately after the concrete comes to rest, open the trap door of the lower hopper and
allow the concrete to fall into the cylinder, bringing the concrete into standard
compaction.
9. Remove the excess concrete above the top of the cylinder by a trowel.
10. Find the weight of cylinder i.e cylinder filled with partially compacted concrete (W2
kgs)
11. Refill the cylinder with same sample of concrete in approx. 4 layers, tamping each layer
with tamping for 25 times in order to obtain full compaction of concrete.
12. Level the mix and weigh the cylinder filled with fully compacted concrete (W3 Kg)
13. Repeat the procedure for different for different a trowel.
 Figure 8: Compaction Factor Test

OBSERVATIONS AND CALCULATIONS:

Weight of cylinder = W1 Kgs.

SR.NO. W/c ratio Wt. With Wt. With Wt. With Wt. With Compaction
partially fully partially fully factor
compaction compaction compacted compacted (W1- W2)/
W2 W3 concrete(W2- concrete(W3- (W3- W1)
(Kgs) (Kgs) W3) W1)
(Kgs) (Kgs)
1 0.5
2 0.6
3 0.7
4 0.7
PRECAUTIONS:
1. The top hopper must be filled gently.
2. The mix should not be pressed or compacted in the hopper.
3. If the concrete in the hopper does not fall through when the trap door is released, it
should be freed by passing a metal rod. A single steady penetration will usually
affect release.

COMMENTS: It is more sensitive, precise than slump test and is particularly useful to
concrete mixes of low workability.

Suggested ranges of values of compaction factors for different placing conditions.

SR. NO. Placing conditions Degree of workability Values of workability

1 Concreting shallow Very low 0.75 to 0.80
section with vibration
2 Concreting of lightly Low 0.80 to 0.85
reinforced section with
vibration
3 Concreting of lightly Medium 0.85 to 0.92
reinforced section
without vibration or
heavily reinforced
with vibration
4 Concreting of heavily High 0.92 to above
reinforced
section without
vibration
 Experiment 15
WORKABILITY OF CONCRETE – VEE BEE 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 centi-meters 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:
 Experiment: 16
FLOW TABLE TEST
(IS: 9103- 1999)

AIM: To determine workability of concrete by flow table test.

APPRATUS:

1) FLOW TABLE: The flow table top is constructed from a flat metal plate of minimum
thickness 1.5mm. the top is in a plan 700mm × 700mm. the center of the table top is
marked with a cross, the lines which run parallel to and out to the edges of the plate, and
with a central circle 200mm dia. The front of the flow table top is 16± 1 kg. the flow
table top is hinged to a base frame using externally mounted hinges. The front of the base
frame shall extend a minimum 120 mm beyond the flow table top in order to provide to
toe board. An upper stop provided on each side of the table so that the lower front edge of
the table can only be lifted 40 ± 1 mm. the lower front edge of the flow table top is
provided with two hard rigid stops which transfer the load to the base frame.

2) MOULD: The mould is made of metal readily not attacked by cement paste or liable to
rust and of minimum thickness 1.5 mm. the moulds in the form of a hollow frustum of a
cone with internal dimensions is: Top dia= 130 ± 2 mm, bottom dia= 200 ± 2mm, height:
200 ± 2mm.

3) TAMPING BAR: The tamping bar is made of a suitable hardwood with tamping part
dimensions 40 × 40 × 200 mm and handle of 120 to 150 mm length.
PROCEDURE:

1. The table is made level and properly supported. The table top and inner surface of
mould is wiped with a damp cloth.
2. The mould is placed centrally on the table. The slump cone is filled with concrete in two
equal layers, each layer tamped lightly 10 times with the wooden tamping bar.
3. After filling the mould, the concrete is struck off flush with the upper edge of the slump
cone. The free area of the table top is cleaned off.
4. The mould is then lifted vertically upward by the handles.
5. The table top is the raised by the handle and allowed to fall 15 times in about 15 seconds.
6. The diameter of the spread concrete is measured in two directions, parallel to the
table edges.
7. The arithmetic mean of the two diameters shall be the measurement of flow in
millimeters.

RESULT:
 Experiment: 17

TEST FOR COMPRESSIVE STRENGTH OF CEMENT CONCRETE

(IS: 516 - 1959)

AIM: Determination of the compressive strength of cement concrete specimens.

APPARATUS: Testing Machine, two steel bearing platens with hardened faces (As per IS:
516-1959).

THEORY: Tests shall be made at recognized ages of the test specimens, the most usual being 7
and 28 days, ages of 13 weeks and one year are recommended if tests at greater ages are
required. Where it may be necessary to obtain the early strength, test may be made at the ages
of 24 hours + 1/2 hour and 12 hours + 2 hours. The ages shall be calculated from the time of the
addition of water to the dry ingredients.
Number of Specimens At least three specimens, preferably from different batches, shall be
made for testing at each selected age.

PROCEDURE: Specimens stored in water shall be tested immediately on removal from water
and while they are still in the wet condition. Surface water and grit shall be wiped off the
specimens and any projecting fines removed. Specimens when received dry shall be kept in
water for 24 hours before they are taken for testing. The dimensions of the specimens to the
nearest 0.2 mm and their weight shall be noted before testing.
Placing the specimen in the Testing Machine, The bearing surfaces of the testing machine shall
be wiped clean and any loose sand or other material removed from the surfaces of the specimens
which are to be in contact with the compression platens. In the case of the cubes, the specimen
shall be placed in the machine in such a manner that the load shall be applied to opposite sides of
the cubes as cast, that is, not to the top and bottom. The axis of the specimen shall be carefully
aligned with the center of thrust of the spherically seated platten. No packing shall be used
between the faces of the test specimen and the steel platten of the testing machine. As the
spherically seated block is brought to bear on the specimen, that movable portion shall be rotated
gently by hand so that uniform section may be obtained. The load shall be applied without shock
and increased continuously at a rate of approximately 140 Kg/sq cm/min. Until the resistance of
the specimen to the increasing load breaks down and no greater load can be sustained. The
maximum load applied to the specimen shall then be recorded and the appearance of the concrete
and any unusual features in the type of failure shall be noted.

CALCULATION: The measured compressive strength of the specimen shall be calculated by

dividing the maximum load applied to the specimen during the test, by the cross sectional area,
calculated from the mean dimensions of section and shall be expressed to the nearest Kg/sq.cm.
Average of three values shall be taken as the representative of the batch provided the individual
variation is not more than + 15% of the average. Otherwise, repeat tests shall be made.
In case of cylinders, a correction factor according to the height to diameter ratio of specimen
after capping shall be obtained from the curve shown in fig. 1 of IS: 516-1959. The product of
this correction factor and the measured compressive strength shall be known as the corrected
compressive strength, this being the equivalent strength of a cylinder having a height/diameter
ratio of two. The equivalent cube strength of the concrete shall be determined by multiplying the
corrected cylinder strength by 5/4.
REPORTING OF RESULTS:
The following information shall be included in the report on each test specimen:
a) Identification mark
b) Date of test
c) Age of specimen
d) Curing conditions including date of manufacture of specimen in the field
e) Weight of specimen
f) Dimensions of specimen
g) Compressive strength
h) Maximum load and
i) Appearance of fractured faces of concrete and type of fractures if these are unusual

RESULT: Compressive strength of Concrete --------------.

COMMENTS: variation is not more than + 15% of the average. Otherwise, repeat tests shall be
made.
 Experiment: 18

TEST FOR SPLITTING TENSILE STRENGTH OF CEMENT CONCRETE (IS: 516 -

1959)

AIM: Determination of the tensile strength of cement concrete specimens.

Scope and Significance:

The tensile strength is one of the basic and important properties of the concrete. The concrete is
not usually expected to resist the direct tension because of its low tensile strength and brittle
nature. However, the determination of tensile strength of concrete is necessary to determine the
load at which the concrete members may crack. The cracking is a form of tension failure.
Apart from the flexure test the other methods to determine the tensile strength of concrete can be
broadly classified as (a) direct methods, and (b) indirect methods. The direct method suffers from
a number of difficulties related to holding the specimen properly in the testing machine without
introducing stress concentration, and to the application of uniaxial tensile load which is free from
eccentricity to the specimen. As the concrete is weak in tension even a small eccentricity of load
will induce combined bending and axial force condition and the concrete fails at the apparent
tensile stress other than the tensile strength. As there are many difficulties associated with the
direct tension test, a number of indirect methods have been developed to determine the tensile
strength. In these tests in general a compressive force is applied to a concrete specimen in such a
way that the specimen fails due to tensile stresses developed in the specimen. The tensile stress
at which the failure occurs is termed the tensile strength of concrete.
The splitting tests are well known indirect tests used for determining the tensile strength of
concrete sometimes referred to as split tensile strength of concrete. The test consists of applying
a compressive line load along the apposite generators of a concrete cylinder placed with its axis
horizontal between the compressive platens. Due to the compression loading a fairly uniform
tensile stress is developed over nearly 2/3 of the loaded diameter as obtained from an elastic
analysis.

When the load is applied long the specimen the generatrix, an element on the vertical diameter of
the cylinder is subjected to a vertical compressive stress.

= (2P/(п L D)) x ((D2/(r x (D – r)) - 1)

And a tensile stress of
(2P/(п L D))

Where, P = compressive load on the cylinder

L = length of the cylinder
D = diameter of cylinder
r and (D-r) are the distance of the elements from the two loads respectively.
 Apparatus:

Compression testing machine weighing machine mixer, tamping roks

Figure 9: SPLINTING TEST

Procedure:

1) Take mix proportion as 1:2:4 with water cement ratio of 0.6. Take 21kg of coarse
aggregate, 10.5 kg of fine aggregate 5.25kg of cement and 3.l5 litres of water. Mix them
thoroughly until uniform colour is obtained. This material will be sufficient for casting
three cylinders of the size 150mm diameter X 300 mm length. In mixing by hand
cement and fine aggregate be first mixed dry to uniform colour and then coarse
aggregate is added and mixed until coarse aggregate is uniformly distributed throughout
the batch. Now the water shall be added and the ingredients are mixed until resulting
concrete is uniform in colour. Mix at least for two minutes.
2) Pour concrete in moulds oiled with medium viscosity oil. Fill the cylinder mould in four
layers each of approximately 75 mm and ram each layer more than 35 times with
evenly distributed strokes.
3) Remove the surplus concrete from the tope of the moulds with the help of the trowel.
4) Cover the moulds with wet mats and put the identification mark after about 3 to 4 hours.
5) Remove the specimens from the mould after 24 hours and immerse them in water for the
final curing. The test are usually conducted at the age of 7-28 days. The time age shall
be calculated from the time of addition of water to the dry ingredients.
6) Test at least three specimens for each age of test as follows
Draw diametrical lines on two ends of the specimen so that they are in the same
axial plane.

 Determine the diameter of specimen to the nearest 0.2 mm by averaging the diameters of
the specimen lying in the plane of premarked lines measured near the ends and the
middle of the specimen. The length of specimen also shall be taken be nearest 0.2 mm by
averaging the two lengths measured in the plane containing pre marked lines.


  Centre one of the plywood strips along the centre of the lower platen. Place the
specimen on the plywood strip and align it so that the lines marked on the end of the
specimen are vertical and centered over the plywood strip. The second plywood strip is
placed length wise on the cylinder centred on the lines marked on the ends of the
cylinder. The assembly is positioned to ensure that lines marked on the end of
specimen are vertical and the projection of the plane passing through these two lines
interest the centre of the platen.


 Apply the load without shock and increase it continuously at the rate to produce a split
tensile stress of approximately 1.4 to 2.1 N/mm2/min, until no greater load can be
 sustained. Record the maximum load applied to specimen
  Note the appearance of concrete and any unusual feature in the type of failure.
 Compute the split tensile strength of the specimen to the nearest 0.25 N/mm2.

OBSERVATION:

SR. NO. Dia of the Length of the Breaking load Splitting

specimen specimen (mm) (N) strength
(mm) (MPa)

1
2
3

CALCULATION:

RESULT:
 Experiment 19
NON-DESTRUCTIVE TESTS

REBOUND HAMMER

AIM

To assess the likely compressive strength of concrete by using rebound hammer as per IS: 13311
(Part 2) - 1992. And Ultrasonic Pulse Velocity Method IS: 13311 (Part 1) - 1992

PRINCIPLE

The rebound of an elastic mass depends on the hardness of the surface against which its mass
strikes. When the plunger of the rebound hammer is pressed against the surface of the concrete, the
spring-controlled mass rebounds and the extent of such a rebound depends upon the surface
hardness of the concrete. The surface hardness and therefore the rebound is taken to be related to
the compressive strength of the concrete. The rebound value is read from a graduated scale and is
designated as the rebound number or rebound index. The compressive strength can be read directly
from the graph provided on the body of the hammer.

APPARATUS

i) Rebound hammer

PROCEDURE

i) Before commencement of a test, the rebound hammer should be tested against the test anvil, to
get reliable results, for which the manufacturer of the rebound hammer indicates the range of
readings on the anvil suitable for different types of rebound hammer.

ii) Apply light pressure on the plunger - it will release it from the locked position and allow it to
extend to the ready position for the test.
iii) Press the plunger against the surface of the concrete, keeping the instrument perpendicular to
the test surface. Apply a gradual increase in pressure until the hammer impacts. (Do not touch
the button while depressing the plunger. Press the button after impact, in case it is not
convenient to note the rebound reading in that position.)

iv) Take the average of about 15 readings.

INTERPRETATION OF RESULTS

The rebound reading on the indicator scale has been calibrated by the manufacturer of the rebound
hammer for horizontal impact, that is, on a vertical surface, to indicate the compressive strength.
When used in any other position, appropriate correction as given by the manufacturer is to be taken
into account.

ULTRASONIC PULSE VELOCITY

AIM

To assess the quality of concrete by ultrasonic pulse velocity method as per IS: 13311 (Part 1) -
1992.
PRINCIPLE
The method consists of measuring the time of travel of an ultrasonic pulse passing through the
concrete being tested. Comparatively higher velocity is obtained when concrete quality is good in
terms of density, uniformity, homogeneity etc.

APPARATUS

FIG. : ULTRASONIC PULSE VELOCITY METER

i) Ultrasonic pulse velocity meter

PROCEDURE

i) Preparing for use: Before switching on the 'V' meter, the transducers should be connected to
the sockets marked "TRAN" and " REC".
The 'V' meter may be operated with either:

a) the internal battery,

b) an external battery or

c) the A.C line.

ii) Set reference: A reference bar is provided to check the instrument zero. The pulse time for the
bar is engraved on it. Apply a smear of grease to the transducer faces before placing it on the
opposite ends of the bar. Adjust the 'SET REF' control until the reference bar transit time is
obtained on the instrument read-out.

iii) Range selection: For maximum accuracy, it is recommended that the 0.1 microsecond range
be selected for path length upto 400mm.

iv) Pulse velocity: Having determined the most suitable test points on the material to be tested,
make careful measurement of the path length ‘L’. Apply couplant to the surfaces of the
transducers and press it hard onto the surface of the material. Do not move the transducers
while a reading is being taken, as this can generate noise signals and errors in measurements.
Continue holding the transducers onto the surface of the material until a consistent reading
appears on the display, which is the time in microsecond for the ultrasonic pulse to travel the
distance 'L'.

The mean value of the display readings should be taken when the units digit hunts between
two values.

Path length
Pulse velocity =
Travel time

v) Separation of transducer leads: It is advisable to prevent the two transducer leads from coming
into close contact with each other when the transit time measurements are being taken. If this is
not done, the receiver lead might pick-up unwanted signals from the transmitter lead and this
would result in an incorrect display of the transit time.

INTERPRETATION OF RESULTS

The quality of concrete in terms of uniformity, incidence or absence of internal flaws, cracks and
segregation, etc., indicative of the level of workmanship employed, can thus be assessed using the
guidelines given below, which have been evolved for characterising the quality of concrete in
structures in terms of the ultrasonic pulse velocity.
Pulse Velocity Concrete Quality
(km/second) (Grading)

Above 4.5 Excellent

3.5 to 4.5 Good

3.0 to 3.5 Medium

Below 3.0 Doubtful