CONTENTS

Ex No. DateName of Experiments Page No. Grade Initials

1Grain size distribution of fine & coarse aggregates

2Bulk density, Voids ratio, Porosity & Specific gravity

3Bulking of sand

4Aggregate crushing value

5Aggregate impact value

6Fineness of cement

7Normal consistency of cement

8Initial &final setting time of cement

9Compressive strength of cement

10Test on timber beam

11Compressive strength of bricks

GRAIN SIZE DISTRIBUTION OF FINE &

COARSE AGGREGATES

Experiment No: 1

Date:

AIM:

To determine the particle size distribution of fine and coarse aggregates.

GENERAL:

The aggregate most of which passes IS: 4.75 mm sieve is classified as fine

aggregate. The fine aggregates obtained from natural disintegration of rocks and

deposited by streams are known as natural sands. Fine aggregates resulting from

crushing of hard stone are known as crushed sand.

The aggregate most of which is retained on IS 4.75 mm sieve is classified as

coarse aggregate. This may be in the form of uncrushed gravel or stone resulting from

natural disintegration of rocks. Crushed gravel or stone is obtained by crushed gravel or

hard stone.

Sieve analysis is carried out for the determination of fine and coarse aggregates

by sieving or screening. Sieves of size 80 mm, 40mm, 20mm, 10 mm, 4.75 mm, 2.36

mm, 1.18 mm, 600 micron, 300 micron &150 micron confirming to IS: 460.

APPARATUS:

a) Balance: -The balance shall be such that it is readable and accurate to 0.1% of

the weight of the test sample.

b) Sieves:- sieves of the sizes given in table 1 & 2 confirming to

IS: 460-1962 shall be used.

PROCEDURE:

Take 1 kg of air-dry sample of the fine aggregate (2 kg of coarse aggregate) and sieve

successively on the appropriate sieves starting with the largest. Care shall be taken to

ensure that the sieves are clean before use. Each sieve shall be taken separately over a

clear tray until not more than a trace passes, but in any case for a period of not less than

2 minutes. If a mechanical sieve shaker is used, arrange the set of sieves in the order of

their aperture sizes in such a way that the sieve having smallest opening comes at the

bottom and a minimum of 10 minutes sieving will be required. Weigh the aggregate

retained in each sieve . Draw a graph taking logarithm (Log 10 ) of aperture size of the

sieve on the X-axis and % finer on the Y-axis.

Reporting of results: -

The result shall be calculated and reported as follows

The sieve opening corresponding to 10% passing (D10) gives effective size.

The ratio of sieve opening corresponding to 60% (D60) to sieve opening

corresponding to 10% passing (D10) gives uniformity coefficient.

The sum of the cumulative % retained in each of the sieves divided by 100 gives the

fineness modulus of the aggregate.

Grading zone can be determined by plotting a graph with logarithm of aperture size

of the sieves versus % finer according to value given in table 3.

OBSERVATIONS AND CALCULATIONS: -

Coarse Aggregate

Weight of coarse aggregate used for sieving = ……………Kg

IS Sieve

size

Wt.Retained

(gm)

%Wt

Retained

Cumulative

%

Wt.Retained

%Wt.

passingRemarks

20 mm

10 mm

4.75 mm

2.36 mm

1.18 mm

600 micron

300 micron

150 micron

Residue

Check

Table 1, sieve analysis of coarse aggregate

Fine aggregate

Weight of fine aggregate used for sieving = ………..…KgIS Sieve

size

Wt.Retained

(gm)

%Wt

Retained

Cumulative %

Wt.Retained

%Wt.

passingRemarks

4.75 mm

2.36 mm

1.18 mm

600 micron

300 micron

150 micron

Residue

Check

Table 2, sieve analysis of fine aggregate

SPECIFICATION FOR FINE AGGREGATE

(IS: 383-1970)

IS SievePercentage passingGrading zone I Grading zone II Grading zone III Grading zone IV

10 mm 100 100 100 100

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

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

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

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

300 micron 05-20 08-30 12-40 15-50

150 micron 00-10 00-10 00-10 00-15

Table: 3-values for grading zones

RESULTS: -

Fine aggregate Coarse aggregate

1.Effective size (D10) mm

2.Uniformity coefficient (D60/D10)

3.Fineness modulus

4.Grading zone

DISCUSSIONS: -

(Discuss about the grading curves obtained. What is the average size of Fine

aggregate and Coarse aggregate in the given sample?)

BULK DENSITY, VOID RATIO, POROSITY

AND SPECIFIC GRAVITY

Experiment No. 2

Date:

AIM:

To determine the bulk density, void ratio, porosity and specific gravity of the

given fine and coarse aggregates in loose and compact states.

GENERAL:

In estimating quantities of materials and in mix computations, when batching is

done on a volumetric basis, it is necessary to know the conditions under which the

aggregate volume is measured viz (a) loose or compact (b) dry or damp. For general

information and for comparisons of different aggregates, the standard conditions are dry

and compact. For scheduling volumetric batch quantities the unit weight in the loose,

damp state should be known.

Bulk density (unit weight) is the weight of a unit volume of aggregate, which is

usually expressed in kg. per litre.

Void ratio refers to the spaces between the aggregate particles. Numerically this

void space is the difference between the gross or overall volume of the aggregate and

the space occupies by the aggregate particles alone. Void ratio is calculated as the ratio

between the volume of voids and volume of solids.

Porosity is the ratio between the volume of voids and the total volume.

Specific gravity of aggregate is the ratio of the specific weight of aggregate and

specific weight of water.

APPARATUS:

a) A balance sensitive of 0.5% of the weight of sample to be weighed.

b) A cylindrical container having sufficient capacity.

c) A tamping rod of 16 mm diameter and 60mm long rounded at one end.

d) A measuring jar.

PROCEDURE: -

Take the weight of the cylindrical container (W1). Fill water in the container up to the

brim and find the weight (W2). From these two, calculate the volume of the container

(V1). Fill the given sample of aggregate 1/3rd full in the container and give 25 strokes

with the rounded end of the tamping rod. Fill the container to overflowing by filling in

the same manner as above in two steps. Remove the surplus aggregate using the

tamping rod as a straight edge. Take the weight of the container with the aggregate

(W3). Add measured quantity of water to the aggregate in the container slowly until the

voids are completely filled with water. Note the volume of water added (V2), (To

verify the value of V2, take the weight of the container with aggregate and water and

find the weight of water added).

For loose aggregate.

Fill the container to overflowing by means of a shovel, the aggregate being

discharged from a height not exceeding 50mm above the top of the container. Level the

surface of the aggregate with a straight edge. Obtain the weight of the aggregate.

Repeat the same procedure used for compacted aggregate to ascertain the other

quantities.

OBSERVATIONS AND CALCULATIONS: -

Sl.

No.Particulars

Fine aggregate Coarse aggregate

Loose Compact Loose Compact

1 Weight of Container (W1) kg

2Weight of Container +Water

(W2) kg

3Weight of Container +

Aggregate (W3) kg

4 Volume of container (V1) lit

5Volume of Water added

=Volume of voids (V2) lit

6Weight of Aggregate

(W3-W1)

7 Volume of Solids (V1-V2))

8

Bulk density =

Wt. of Aggregate

Total volume of aggregate

9Void ratio = Volume of voids

Volume of solids

10Porosity = Volume of voids

Total volume of aggregate

11

Sp. Wt. of aggregate =

Wt. of Aggregate

Volume of aggregate

12

Specific gravity =

Sp. Wt. of aggregate

Sp. Wt. of water

RESULTS:

Sl

NOParameters

Fine aggregate Coarse aggregate Remarks

Loose Compact Loose Compact

1 Bulk density (kg/litre)

2 Void ratio

3 Porosity

4 Specific gravity

DISCUSSION:

(Compare the values with the usual value of the aggregates recommended for normal

concreting work)

BULKING OF SAND

Experiment No: 3

Date:

AIM:

To determine the bulking characteristics of given sand.

GENERAL: -

The free moisture content of fine aggregate results in bulking of volume. Free

moisture forms a film around each particle. This film of moisture exerts surface tension,

which keeps the neighboring particles away from it. Hense no point of contact is

possible between the particles. This causes bulking of the volume .The extent of

bulking will depend upon the percentage of moisture content and particle size of the

fine aggregate. Bulking increases with the increase in moisture content up to a certain

limit and beyond that, further increase in moisture content results in the decrease in

volume.

Sand brought to work site may contain an amount of moisture, which will cause

bulking. When it is loosely filled into a measuring container, it occupies larger volume

than it would occupy if dry. Hence if sand intend to use in a concrete mix is a measure

by loose volume, it will be necessary to increase the volume of sand by ‘percentage

bulking’. Otherwise the yield of concrete will be reduced and the mix becomes

deficient in sand and the aggregate is prone to segregation resulting in honey-combing

of concrete.

APPARATUS: -

Measuring jar, balance, scale and porcelain bowl.

PROCEDURE: -

Take about 200ml. of dry sand from the sample and find its weight. Add water at 2%

by weight of dry sand and mix it thoroughly by hand. Pour the damp sand into the

measuring jar and consolidate it by shaking. Level the top surface using the scale. Note

its volume (V). Repeat the test with different % of water. Finally pour water into the

measuring jar containing the moist sand until the water just submerge the sand

completely. Note the volume of sand (V0). Calculate the % bulking using the formula.

Percentage bulking = V- V0 × 100

V0

Draw the Percentage bulking versus moisture content curve and find the maximum

Percentage bulking and corresponding moisture content.

RESULT:-

1. Maximum percentage of bulking =

2. Moisture content at maximum bulking =

DISCUSSION: -

OBSERVATION :-

Sl.noPercentage

moisture

Volume of

Water added

(ml)

Volume of

Moist sand

(V ml)

Percentage bulking

= V- V0 × 100

V0

Remarks

1 2

2 4

3 6

4 8

5 10

6 15

7 20

8 25

9 30

AGGREGATE CRUSHING VALUE

Experiment No: 4

Date:

AIM:-

To determine the aggregate crushing value of the given coarse aggregate.

GENERAL: -

The aggregate crushing value gives a relative measure of the resistance of an

aggregate to crushing under a gradually applied compressive load. Crushing value is

defined as the ratio of fines passing a standard sieve produced by crushing under

standard condition to the weight of coarse aggregate expressed as a percentage.

Aggregate crushing values as determined by the IS code method shall not

exceed 30 for aggregate to be used for making concrete for wearing surface such as

roads and runways and 45 for uses other than wearing surface.

APPARATUS: -

An open-ended 150mm cylindrical cell with appropriate base plate and metal

tamping rod 16mm diameter 45cm long rounded at one end. A balance of capacity 5kg,

IS sieves 12.5mm, 10mm and 2.36mm, compression testing machine capable of

applying a load of 40T and which can be operated to give a uniform rate of loading so

that a maximum load of 40T is reached in 10 minutes.

PROCEDURE: -

Take required quantity of aggregate passing on a 12.5mm sieve and retained on

a 10mm sieve. When aggregate of the required size is not available, test may be

conducted on the available sample, the specifications for cylinder and sieve separating

the fines may be taken from IS: 2386-1963. The aggregate should be in a saturated

surface dry condition. Fill the test sample of aggregates in the cylinder in thirds, each

part being subjected to 25 strokes from the tamping rod. Take the weight of the test

sample (A) after leveling the surface of the aggregate and insert the plunger sot that at

rests horizontally on the surface of the aggregates. Place the apparatus with the test

sample and the plunger between the platens of the testing machine and apply the load

fairly at uniform rate so that the total load of 40T reaches in 10 minutes.

Release the load and remove the material from the cylinder and sieve it through

2.36mm sieve. Collect and weigh the fraction passing the sieve (B). Aggregate

crushing value can be calculated as (B/A) x 100.

OBSERVATIONS AND CALCULATIONS:-

Weight of dry sample passing through IS 12.5mm sieve and retained on

IS 10mm sieve (A) =

Weight of aggregate passing through the IS 2.36mm

Sieve after the test (B) =

Aggregate crushing value =

RESULT: -

Aggregate crushing value for standard size aggregate =

DISCUSSION: -

(Discussion the suitability of aggregate for construction)

AGGREGATE IMPACT VALUE

Experiment No: 5

Date:

AIM: -

To determine the impact value of the given aggregates.

GENERAL:-

The property of a material to resist impact is known as toughness. Due to

movement of vehicles on the road aggregates are subjected to impact resulting in their

breaking down into smaller pieces. The aggregates should therefore have sufficient

toughness to resist their disintegration due to impact. This characteristic is measured by

impact value test. The aggregate impact value is a measure of resistance to sudden

impact or shock, which may differ from its resistance to gradually applied compressive

load.

APPARATUS: -

The apparatus of the aggregate impact value test as per IS: 2386 (Part IV) 1963

consists of:

(i) A testing machine weighing 45 to 60 kg and having a metal base with a

plane lower surface of not less than 30cm in diameter. It is supported on

level and plane concrete floor of minimum 450mm thickness. The

machine should also have provisions for fixing its base.

(ii) A cylindrical steel cup of internal diameter 102mm, depth 50mm and

minimum thickness 6.3mm.

(iii) A metal hammer weighing 13.5 to 14 kg the lower end is cylindrical in

shape, is 50mm long, 100mm in diameter with a 2mm chamfer at the

lower edge and case hardened. The hammer should slide freely between

vertical guides and be concentric with the cup. The free fall of the

hammer should be within 380+ 5mm

(iv) A cylindrical metal measure having internal diameter of 75mm and

depth 50mm for measuring aggregates.

(v) Tamping rod 10mm in diameter and 230mm long rounded at one end.

(vi) A balance of capacity not less than 500g readable and accurate up to

0.1g.

PROCEDURE:-

Take 300g dried aggregate which passes through 12.5mm IS: sieve and retained

in 10mm IS: sieve. Pour the aggregate to fill about 1/3 depth of measuring cylinder and

give 25 blows using the rounded end of the tamping rod. Add two more layers in

similar manner to fill the mould completely. Strike of the surplus aggregates and takes

the weight of aggregates to nearest grams (W1). Fix the cup firmly in position on the

base of machine and place whole of the test sample in it and compact by giving 25

gentle strokes with tamping rod. Raise the hammer until its lower face is 380mm above

the surface of the aggregate sample in the cup and allow it to fall freely on the

aggregate sample. Give 15 such blows at an interval of not less than 1 second between

successive falls. Remove the crushed aggregates from the cup and sieve it through 2.36

mm IS: sieve until no further significant amount passes in one minute. Weigh the

fraction passing the sieve to an accuracy of 1g (W2). Also weigh the fraction retained in

the sieve. Aggregate impact value can be calculated as aggregate impact value =

(W2/W1) x 100 and should be expressed as a nearest whole number.

The following precautions should be taken while conducting the test.

(i) The plunger should be placed centrally so that it falls directly on the

aggregate sample and does not touch the walls of the cylinder in the

order to ensure that the entire load is transmitted on to the aggregates.

(ii) In the operation of sieving the aggregates through 2.36mm IS sieve, the

sum of the weights of the fraction retained and passing the sieve should

not differ from the original weight of the specimen by more than 1g.

(iii) The tamping is to be done properly by gently dropping the tamping rod

and not by hammering action. Also the tamping should be uniform over

the surface of the aggregate taking care that the tamping rod does not

frequently strike against the walls of the mould.

OBSERVATIONS AND CALCULATIONS:-

Total weight of dry sample (W1) =

Weight of portion passing IS 2.36mm sieve (W2) =

Aggregate impact value = (W2/W1) X100

RESULT: -

Aggregate impact value =

DISCUSSION: -

(Discuss the suitability of the aggregate for road construction)

FINENESS OF CEMENT

Experiment No:-6

Date:

AIM :

To determine the Finess of cement by dry sieving

GENERAL:

Fines of cement has significant role on the rate of hydration and on the rate of

evolution of heat. Cement which is more finely ground hardened more rapidly and

has a higher rate of heat evolution at early ages. Greater finesses improves the

cohesiveness of concrete mix and quality of water rising to the surface of concrete

known as bleeding, is reduced.

Shrinkage cracking is related to the rate of development of strength of concrete. In

general, cement which gains more strength rapidly are more subjected to cracking.

Increasing the fineness of any particular cement, raises its rate of development of

strength and so indirectly increases the risk of shrinkage crack formation.

APPARATUS :

IS 90 micron sieve, weighing balance with a sensitivity of 0.1 gm.

PROCEDURE :

Weigh 100gm. of given sample of cement. Place it on a standard IS 90 micron

sieve. Breaking down any air set lumps in the cement sample with finger. Continuously

sieve the sample with a gently wrist motion for a period of, rotating the sieve

continuously throughout the sieving. Weigh the residue after 15 minutes of sieving.

Repeat the procedure for two more such samples.

OBSERVATION AND CALCULATIONS:

Weight of cement taken =

Weight of residue after 15 minutes of sieving =

RESULTS :

Fineness of cement of dry sieving =

DISCUSSION :

(Discuss the quality of the given sample of cement by comparing with IS specifications.)

Sl no

Type of cement

Wt. Of cement

W1

Wt of residue

W2

% Wt.of

residue

W2 X 100

W1

Average % of residue

IS specification

Remarks

1

2

3

NORMAL CONSISTENCY OF CEMENT

Experiment No:7

Date:

AIM:-

To determine the normal consistency of the given sample of cement.

GENERAL:-

Since different batches of cement differ in fineness, pastes with the same water

content may differ in consistency when first mixed. For this reason the consistency of

the paste is standardized by varying the water content until the paste has a given

resistance to penetration when it is first mixed.

Consistency is a state of flow and varies with the amount of water added to the

given quantity of cement. More water increases the plasticity of the mortar to flow

whereas reducing its quantity in the paste makes it hard and stiff. The normal

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 Vicat mould when the

cement paste is tested. The value of the amount of water required to prepare a paste of

normal consistency is necessary for conducting other tests such as tensile test,

soundness test, setting time test and compressive strength test.

APPARATUS:-

Vicat’s apparatus with Vicat’s plunger, weighing balance, stop watch,

measuring jar, glass plates and porcelain bowl.

PROCEDURE:-

Take 400g of cement and break air set lumps of cement if any by hand. Add

water about 20 percentage by weight of cement. Start a stopwatch when water is added

to the dry cement. Prepare the cement paste such that the gauging time is not less than 3

minutes nor greater than 5 minutes. The gauging time is counted from the time of

adding water to the dry cement until commencing to fill the mould. Fill the mould

completely and during filling shake the mould slightly to expel air. After filling level

the surface of the mould. Place the mould with the test block with non-porous plate

under the plunger. Lower the plunger gently to touch the surface of the test block and

release it quickly. Note the reading on the scale. Prepare the trial pastes with varying

percentages of water until the amount of water necessary for making up the normal

consistency as defined is found.

RESULT:

Normal consistency of cement =

DISCUSSION:

OBSERVATIONS:

Sl

no

Percentage of

Water added (%)

Quantity of

Water (cc)

Plunger

Reading (mm)

INITIAL AND FINAL SETTING TIME OF CEMENT

Experiment No.8

Date:

AIM:

To determine the initial and final setting time of cement.

GAENERAL:

It is essential that cement set neither too rapidly nor too slowly. In the first case

there might be insufficient time to transport and place the concrete before it becomes

too rigid. In the second case too long a setting time tends to slow up the work unduly

and it might postpone the actual use of structure because of inadequate strength at the

desired age. As per IS: 4081-1968 the setting time of cements when tested by Vicat

apparatus are as follows.

Particulars

Ordinary Portland

cement

Rapid hardening

cement

Low heat

cement

1. Initial setting time

in minutes (not

less than)

30 30 60

2. Final setting time

in minutes (not

greater than )

600 600 600

APPARATUS:

Vicat’s apparatus with needles, weighing balance, stopwatch, measuring jar, porcelain

bowl.

PROCEDURE:

Take 400gm. of cement and prepare a neat cement past with 0.85 times of water

required for normal consistency. The preparation of test block for the test is same as

that for the normal consistency test. Start a stopwatch when water is added to the dry

cement. Place the test block confined in the mould and resting on the non-porous plate

below the needle of the Vicat apparatus. Lower the needle gently to touch the surface

of the test block and release quickly. In the beginning the needle completely pierces the

test block. Repeat this procedure until the needle pierces the block by 5 ± 0.5mm

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

water is added to the cement and the time at which the needle fails to pierce the test

block by 5 ± 0.5mm is the initial setting time.

For determining the final setting time, replace the needle of Vicat apparatus by

the needle with an annular attachment. The cement is considered finally set when upon

applying the final setting needle gently to the surface of the test block, the needle makes

an impression thereon, while the attachment fails to do so. The period elapsing

between the time when water id added to the cement and the time at which the needle

make an impression on the surface of the test block while the attachment fails to do so

shall be the final setting time. In the event of a scum forming on the surface of the test

block, use underside of the test block for the determination of final setting time.

RESULT:

Initial setting time of the given sample =

Final setting time of the given sample =

DISCUSSION:

(Discuss the quality of the given sample of cement comparing with IS

specifications)

OBSERVATIONS:

INITIAL SETTING TIME OF CEMENT

Type of cement =

Weight of cement =

Quality of water added =

SL NO Time Reading(mm) Remarks

COMPRESSIVE STRENGTH OF CEMENT

EXPERIMENY NO.9

Date :

AIM :

To determine the compressive strength of given sample of cement.

GENERAL :

The mechanical strength of hardened cement is the property of material that is

needed in the structural designs. The strength of cement is usually determined from

tests on mortar made with cement. The compressive strength of cement is determined as

represented by compressive strength tests on mortar cubes prepared by standard

method.

APPARATUS :

Moulds for the cube specimens of 50 cm2 face area, vibrating machine,

compression testing machine, apparatus for gauging and mixing mortar etc.

PROCEDURE :

The test specimen shall be in the form of cubes having of face area equal to 50

cm2 made of cement mortar 1:3 .In assembling the mould ready for use, cover the joint

between the halves of the mould and between the contact surface of the bottom of the

mould and base plate with a thin film of petroleum jelly, in order to ensure that no

water escapes during vibration. Coat the interior faces of the mould with thin coat of

mineral oil. Place the assembled mould on the table of the vibration machine and firmly

hold it in position by means of suitable clamp.

The material for each cube shall be cement W1 =200 gm

P +3

Standard sand W2 =3W1= 600 gm, water = 4 (W1+W2) g, where p is the 100

Percentage of water for standard consistency.

Place the mixture of cement and standard sand in a non-porous plate. Mix dry with

a trowel for one minute and add the required quantity of water and mix until the

mixture is of uniform colour. The mixing time should not exceed 4 minutes and should

not be less than 3 minutes.

Immediately after mixing the mortar fill it in the cube mould and rod 20 times with

a rod in three layers. Place the remaining quantity of mortar in the hopper of the cube

moulds and pressed it again and then compact the mortar by vibration. The period of

vibration shall be 2 minutes at the specified rate of 12000+ 400 vibrations per minutes.

At the end of the 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 the surface

with the blade of the trowel.

Keep the filled mould at a temperature of 27 + 20C in an atmosphere of at least

90% relative humidity for 24 hrs. At the end of the period remove them from the

moulds and immediately submerge in fresh water and keep there until taken out just

prior to testing.

TESTING OF MORTAR CUBES

Test 3 cubes for compressive strength at the period mentioned in the IS

specification. The cubes are tested on their sides without any packing. The load shall be

readily and uniformly applied at the rate of 350kg / cm2 / min.

OBSERVATION AND CALCULATIONS

Weight of cement for one cube = 200g

Weight of sand = 600g

Weight of water for one cube =

Area of the cube face =

RESULT:

The average value of compressive strength of cement sand mortar cubes at

(i) 3days =

(ii) 7days =

DISCUSSION:

(Discuss (i) standard sand (ii) the quality of the given sample of cement)

Sample

no At 3 days age At 7 days age

LoadCompressive

Strength

Average

Compressive

Strength

LoadCompressive

Strength

Average

Compressive

Strength

(N) (N/mm2) (N/mm2) (N) (N/mm2) (N/mm2)

1

2

3

TEST ON TIMBER BEAM

Experiment No:-10

Date:

AIM :

To determine the following properties of the timber specimen by conducting static

bending test.

1) Fibre stress at limit of proportionality

2) Modulus of rupture.

3) Modulus of elasticity

4) Elastic resilience.

GENERAL :

Standard size of specimen is 5 x 5 x 75 cm with 70 cm span. Where a standard

specimen cannot be obtain the dimensions of the test specimen shall be such as to

make the span l = 14 times the depth. Central deflections shall be measured at load

intervals of 50 kg.

EQUIPMENT :

30T U. T. M,Scale.

PROCEDURE :

Measure the size of the specimen and fix the span. Assuming the

maximum fibre stress ‘f ‘ (say 1000 kg / cm2) calculate the maximum central (W) the

specimen can carry.

M = wl = f Z, hence W = 4 f Z

4 l

where M is Maximum B.M

Z is the section modulus = bd 2 where ‘b ‘and ‘d ‘ are the breadth and

6

depth of the specimen.

Select a suitable loading range and adjust the machine for that range. Mount the

beam supports over the cross head at correct span and place the specimen, fix the

special loading device to the cylinder device at top. Start the motor and slowly open the

inlet valve until the ram is floated. Adjust the pointer to the zero reading, raise the cross

head the central loading device just touches the top of the beam specimen .Adjust the

deflection dial to zero reading. Now slowly load the specimen opening the inlet value

and note deflections corresponding to the load increments until the specimen fails. Also

note the maximum load .Now draw load deflection curve. Determine the slope of the

straight line portion of the graph (P1)

∆

OBSERVATIOS :

Load, kg

Central

deflection,mm

1. Span of the test specimen l (mm) =

2. Breadth of the test specimen b (mm) =

3. Depth of the test specimen d (mm) =

4. section modulus = bd 2 (mm3) =

6

5. Moment of inertia I = bd3 (mm4) =

12

6. Load at limit of proportionality P (N) =

7.Maximum load P1(N) =

8. Fibre stress at limit of proportionality = Pl (N/mm2) =

4Z

9. Equivalent Fibre stress at Maximum

load = = P 1 l (N/mm2) =

4Z

10. Modulus of elasticity , =P1l3/48I∆ (N/mm2) =

11. Elastic resilience, work to limit of proportionalty/volume =

RESULT :

1. Fibre stress at limit of proportionality =

2. Modulus of rupture =

3. Modulus of elasticity , =

4. Elastic resilience, =

DISCUSSION :

(Discuss the quality of the given timber.)

COMPRESSIVE STRENGTH OF BRICKS

EXPERIMENT NO.11

Date :

AIM

To determine the compressive strength of the given sample of brick.

GENERAL :

Bricks are generally subjected to compression and rarely to tension. The usual

crushing strength of common hand moulded well burnt bricks is about 5 to 10 N/mm2

varying according to the nature of preparation of the clay.

APPARATUS:

A compression testing machine.

PROCEDURE :

Take 5 bricks, remove unevenness observed in the bed face to provide two

smooth parallel faces by grinding. Immerse the bricks in water at room temperature for

24 hours. Take out the specimen from water and drain out any surplus moisture at room

temperature. Fill the frog (if provided) and all voids in the bed face flush with cement

mortar. Remove and wipe out any traces of moisture.

Place the specimen with flat faces horizontal and mortar filled face facing

upwards between two 3-plywood sheet each of 3 mm thickness and carefully cantered

between plates of the testing machine. Apply an axial load at a uniform rate 14 N/mm2

Per minute till failure and note the maximum load at failure.

RESULT:

Average compressive strength of brick =

DISCUSSION :

(Discussion the quality of the given sample of bricks).

OBSEVATION AND CALCULATIONS

Brick No Dimensions of

the brick

(LxBxD ) mm

Average area

of the bed face

mm2

Maximum

load at

failure(N)

Compressive

strength

(N/mm2 )

1

2

3

4

5

Maximum Load of failure

Compressive strength = _________________________

Average area of the bed face