plain and reinforced concrete practical 4th term dk mamonai

28
PRC- Practical Sir Aneel Kumar 09CE37 1 Practical # 1 : To Prepare the concrete cubes and cylinders of 1:2:4 ratio. APPARATUS : Cube and cylinder mould for casting , weighing machine , sulpher bucket , capping mould and mechanical mixer MATERIALS USED : Fine Aggregates: Coarse Aggregates: Cement : Water = cement * w/c ratio = THEORY : In order to determine the compressive strength ,concrete cubes and cylinders are to be prepared for testing of its compressive strength . It is very important because the compressive strength is criteria for its quality. The strength is expressed in kg / cm 2 . At least three specimens should be used for Testing. PROCEDURE : Take out material all fine and coarse aggregates and cement and weight them accordingly Use Mechanical mixer to mix all these together rigidly. Now take out the fresh concrete from the mixer and fill the required moulds Using Vibrating table to stabilize the concrete easily Regular compaction is required in this process Leave the moulds filled with concrete for 7 days as to attain their strength and shape By using melted suplher , capping is provided . Now cubes are ready for testing

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Page 1: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

1

Practical # 1 : To Prepare the concrete cubes and cylinders of 1:2:4

ratio.

APPARATUS : Cube and cylinder mould for casting , weighing machine , sulpher bucket , capping

mould and mechanical mixer

MATERIALS USED :

Fine Aggregates:

Coarse Aggregates:

Cement :

Water = cement * w/c ratio =

THEORY : In order to determine the compressive strength ,concrete cubes and cylinders are to be

prepared for testing of its compressive strength . It is very important because the compressive

strength is criteria for its quality. The strength is expressed in kg / cm2 . At least three specimens

should be used for Testing.

PROCEDURE :

Take out material all fine and coarse aggregates and cement and weight them accordingly

Use Mechanical mixer to mix all these together rigidly.

Now take out the fresh concrete from the mixer and fill the required moulds

Using Vibrating table to stabilize the concrete easily

Regular compaction is required in this process

Leave the moulds filled with concrete for 7 days as to attain their strength and shape

By using melted suplher , capping is provided .

Now cubes are ready for testing

Page 2: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

2

Practical # 2 : To determine the compressive strength of concrete cubes

and cylinders of 1:2:4 ratio.

AIM:- To Perform compression test on UTM.

APPARATUS :- A UTM or A compression testing m/c, cylindrical or cube shaped concrete block ,

mixing machine and balance.

Materials :

Concrete cube dimensions :

Concrete cylinder dimensions:

THEORY :- Several structures components such as columns and struts are subjected to compressive

load in applications. These components are made of high compressive strength materials. Not all the

materials are strong in compression. Several materials, which are good in tension, are poor in

compression. Contrary to this, many materials poor in tension but very strong in compression. Cast

iron is one such example. That is why determine of ultimate compressive strength is essential before

using a material. This strength is determined by conduct of a compression test.

Compression test is just opposite in nature to tensile test. Nature of deformation and fracture is quite

different from that in tensile test. Compressive load tends to squeeze the specimen. Brittle materials

are generally weak in tension but strong in compression. Hence this test is normally performed on cast

iron, cement concrete etc. But ductile materials like aluminium and mild steel which are strong in

tension, are also tested in compression.

TEST SET-UP, SPECIFICATION OF M/C AND SPECIMEN DETAILS :

A compression test can be performed on UTM by keeping the test-piece on base block and moving

down the central grip to apply load. It can also be performed on a compression testing machine. A

compression testing machine . it has two compression plates/heads. The upper head moveable while

the lower head is stationary. One of the two heads is equipped with a hemispherical bearing to obtain.

Uniform distribution of load over the test- piece ends. UTM tells the load applied on a body.

SPECIMEN :- In cylindrical specimen, it is essential to keep h/d < 2 to avoid lateral instability due to

bucking action. Specimen size = h < 2d.

Page 3: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

3

PROCEDURE :-

1. Dimension of test piece is measured at three different places along its height/length to determine

the average cross-section area.

2. Ends of the specimen should be plane . for that the ends are tested on a bearing plate.

3. The specimen is placed centrally between the two compression plates, such that the centre of

moving head is vertically above the centre of specimen.

4. Load is applied on the specimen by moving the movable head.

5. The load and corresponding contraction are measured at different intervals. The load interval may

be as 500 kg.

6. Load is applied until the specimen fails.

OBSERVATION FOR RATIO 1:2:4 Cubes :-

Size of Cube =

Area of Cube =

S.No. Applied load (P) in Newton Recorded change in length (mm)

1

2

3

CALCULATION :-

Compressive Strength for 1st Cube = Load / Area =

Compressive Strength for 2nd Cube =

Compressive Strength for 3rd Cube=

Page 4: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

4

OBSERVATION FOR RATIO 1:2:4 Cylinders :-

Size of Cylinder =

Area of Cylinder =

S.No. Applied load (P) in Newton Recorded change in length (mm)

1

2

3

CALCULATION :-

Compressive Strength for 1st Cylinder = Load / Area =

Compressive Strength for 2nd Cylinder =

Compressive Strength for 3rd Cylinder =

RESULT :- Compressive strength of given specimens(cubes) =____ Nmm2, ____ Nmm2, _____ Nmm2

Compressive strength of given specimens(cylinders) =____ Nmm2, ____ Nmm2, _____ Nmm2

Page 5: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

5

Practical # 3 : To Prepare the concrete cubes and cylinders of 1:1:2

ratio.

APPARATUS : Cube and cylinder mould for casting , weighing machine , sulpher bucket , capping

mould and mechanical mixer

MATERIALS USED :

Fine Aggregates:

Coarse Aggregates:

Cement :

Water = cement * w/c ratio =

THEORY : In order to determine the compressive strength ,concrete cubes and cylinders are to be

prepared for testing of its compressive strength . It is very important because the compressive

strength is criteria for its quality. The strength is expressed in kg / cm2 . At least three specimens

should be used for Testing.

PROCEDURE :

Take out material all fine and coarse aggregates and cement and weight them accordingly

Use Mechanical mixer to mix all these together rigidly.

Now take out the fresh concrete from the mixer and fill the required moulds

Using Vibrating table to stabilize the concrete easily

Regular compaction is required in this process

Leave the moulds filled with concrete for 7 days as to attain their strength and shape

By using melted suplher , capping is provided .

Now cubes are ready for testing

Page 6: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

6

Practical # 4 : To Perform Compression test to the concrete cubes and

cylinders of 1:1:2 ratio.

AIM:- To Perform compression test on UTM.

APPARATUS :- A UTM or A compression testing m/c, cylindrical or cube shaped concrete block ,

mixing machine and balance.

Materials :

Concrete cube dimensions :

Concrete cylinder dimensions:

Theory: Same as previous practical

Procedure: Same as previous practical

OBSERVATION FOR RATIO 1:1:2 Cubes :-

Size of Cube =

Area of Cube =

S.No. Applied load (P) in Newton Recorded change in length (mm)

1

2

3

Page 7: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

7

CALCULATION :-

Compressive Strength for 1st Cube = Load / Area =

Compressive Strength for 2nd Cube =

Compressive Strength for 3rd Cube=

RESULT :- Compressive strength of given specimens(cubes) =____ Nmm2, ____ Nmm2, _____ Nmm2

VIVA-QUESTIONS :-

· Compression tests are generally performed on brittles materials-why ?

· Which will have a higher strength : a small specimen or a full size member made of the same material ?

· What is column action ? how does the h/d ratio of specimen affect the test result ?

· How do ductile and brittle materials in their behaviour in compression test ?

· What are bi-modulus materials ? Give examples.

Page 8: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

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Practical # 5 : To Prepare and determine the tensile strength of concrete

cylinders of ratio 1:1:2 .

APPARATUS :- A UTM, and concrete cylinders.

MATERIALS:

F.A =

C.A=

Cement =

Water = Cement * w/c ration =

THOERY :- Concrete has low tensile strength . An average value of 10% of compressive strength

concrete posses tensile strength.

Due to uniform tensile stress acting horizontally along the length of cylinders , the cylinder

splits vertically into two halves and because of this the test is also known as “ Spilt test” The Tensile

strength of concrete is given by formula

St = 2 P / π D L

PROCEDURE :- Once the cylinders are casted in the lab and after 7 days it is taken for the test after

that

1. Put the concrete cylinder in UTM

2. Before starting of test , put the load option to zero which means you are testing a fresh

cylinder

3. Also switch on the machine in Max peak hold position , sp that maximum load reading must be

recorded otherwise you will loose the maximum peak load once cylinders breaks

4. Close the safety guards to avoid any accidents

5. Apply the load into small increaments

6. Cylinder will spilt into two halves when test is successful

Observations For Ratio 1:1:2 :-

Page 9: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

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Load on 1st Cylinder : Load on 2nd Cylinder:

Area = Area:

Diameter = Diameter:

Length = Length:

Calculations For Ratio 1:1:2 :-

For 1st Rod :

Applying Formula =

St = 2 P / π D L =

For 2nd Rod:

Applying Formula =

St = 2 P / π D L =

Page 10: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

10

Practical # 6 : To determine the tensile strength and elongation of the

given steel rods.

To study the UTM and perform the tensile test.

APPARATUS :- A UTM, mild steel specimen, vernier caliper/micrometer.

MATERIALS : Weight of Bar 1 =

Weight of Bar 2 =

THEORY :- Various m/c and structure components are subjected to tensile loading in numerous

application. For safe design of these components, there ultimate tensile strength and ductility one to

be determine before actual use. Tensile test can be conducted on UTM.

A material when subjected to a tensile load resists the applied load by developing internal resisting

force. These resistances come due to atomic bonding between atoms of the material. The resisting

force for unit normal cross-section area is known as stress.

The value of stress in material goes on increasing with an increase in applied tensile load, but it has a

certain maximum (finite) limit too. The minimum stress, at which a material fails, is called ultimate

tensile strength. The end of elastic limit is indicated by the yield point (load). This can be sen during

experiment as explained later in procedure with increase in loading beyond elastic limit original cross-

section area (Ao) goes on decreasing and finally reduces to its minimum value when the specimen

breaks.

PROCEDURE :-

1. The load pointer is set at zero by adjusting the initial setting knob.

2. The dial gauge is fixed and the specimen for measuring elongation of small amounts.

3. Measuring the diameter of the test piece by vernier caliper at least at three places and determine

the mean value also mark the gauge length.

4. Now the specimen is gripped between upper and middle cross head jaws of the m/c.

5. Start the m/c and take the reading.

6. The specimen is loaded gradually and the elongation is noted until the specimen breaks.

Page 11: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

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OBSEVATION FOR 1ST ROD:-

(I) Initial diameter of specimen d1 = _________________________

(II) Initial gauge length of specimen L1 =________________________

(III) Initial cross-section area of specimen A1 = ___________________________

(IV) Ultimate load after specimen breaking F = ____________________________

(V) Final length after specimen breaking L2 = ______________________________

(VI) Dia. Of specimen at breaking place d2 = ______________________________

(VII) Cross section area at breaking place A2 = __________________________________

CALCULATION :-

(i) Ultimate tensile strength =

(ii) Percentage elongation % =

RESULT :-

CONCLUSION :-

OBSEVATION FOR 2ND ROD:-

(I) Initial diameter of specimen d1 = _________________________

(II) Initial gauge length of specimen L1 =________________________

(III) Initial cross-section area of specimen A1 = ___________________________

(IV) Ultimate load after specimen breaking F = ____________________________

(V) Final length after specimen breaking L2 = ______________________________

(VI) Dia. Of specimen at breaking place d2 = ______________________________

(VII) Cross section area at breaking place A2 = __________________________________

Page 12: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

12

CALCULATION :-

(i) Ultimate tensile strength =

(ii) Percentage elongation % =

RESULT :-

CONCLUSION :-

PRECAUTIONS :-

1. The specimen should be prepared in proper dimensions.

2. The specimen should be properly to get between the jaws.

3. Take reading carefully.

4. After breaking specimen stop to m/c.

VIVA-QUESTIONS :-

· Which steel have you tested ? what is its carbon content ?

· What general information are obtained from tensile test regarding the properties of a material ?

· Which stress have you calculated : nominal stress or true stress ?

· What kind of fracture has occurred in the tensile specimen and why ?

· Which is the most ductile metal ?How much is its elongation ?

Page 13: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

13

Practical # 7: To calculate the diameter of different steel bars

APPARATUS : Weighing machine and scale

MATERIALS : Steel Bars

THEORY : Concrete mixes have high resistance to compressive stresses however any appreciable

tension ( e.g due to bending ) will break the microscopic rigid lattice resulting in cracking and

separation of the concrete.

If a material with high strength in tension such as steel is placed in concrete , then the composite

material, reinforced concrete , resist compression but also bending , and other direct tensile actions. A

reinforced concrete section where the concrete resist the compression and steel resists the tension .So

it is necessary to use the steel bars of different diameter for different type of work.

PROCEDURE :

Take the steel bars of different sizes

Weigh the steel bars in kilograms

Measure the length of steel bars with scale

Calculate the weight per unit area

Apply the formula and get the result

OBSERVATIONS FOR 1ST ROD :

Weight of 1st Bar =

Length of 1st Bar =

Page 14: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

14

CALCULATIONS FOR 1ST ROD :

FORMULA = 22 / 28 * d 2 * 0.00785

Unit weight = Weight / Length

d=

OBSERVATIONS FOR 2nd ROD :

Weight of 2nd Bar =

Length of 2nd Bar =

CALCULATIONS FOR 2nd ROD :

FORMULA = 22 / 28 * d 2 * 0.00785

Unit weight = Weight / Length

d=

RESULTS : Diamter of Bar (1) = Diameter of Bar (2) =

Page 15: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

15

Practical # 8 : To prepare the plain concrete beam of ratio 1:2:4

APPARATUS : beam mould for casting , weighing machine , sulpher bucket , capping mould and

mechanical mixer

MATERIALS USED :

Fine Aggregates:

Coarse Aggregates:

Cement :

Water = cement * w/c ratio =

THEORY : In order to determine the compressive strength ,beams are to be prepared for testing of

its compressive strength . It is very important because the compressive strength is criteria for its

quality. The strength is expressed in kg / cm2 . At least three specimens should be used for Testing.

PROCEDURE :

Take out material all fine and coarse aggregates and cement and weight them accordingly

Use Mechanical mixer to mix all these together rigidly.

Now take out the fresh concrete from the mixer and fill the required moulds

Using Vibrating table to stabilize the concrete easily

Regular compaction is required in this process

Leave the moulds filled with concrete for 7 days as to attain their strength and shape

By using melted suplher , capping is provided .

Now cubes are ready for testing

Page 16: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

16

Practical # 9 : To determine the flexural strength of plane concrete

beam.

Apparatus : Plain concrete beams, UTM

Theory:

This test method is used to determine the flexural strength of specimens prepared and cured in

accordance with Test Methods C42/C42M or Practices C31/C31M or C192/C192M. Results are

calculated and reported as the modulus of rupture. The strength determined will vary where there

are differences in specimen size, preparation, moisture condition, curing, or where the beam has

been molded or sawed to size.

The results of this test method may be used to determine compliance with specifications or as a

basis for proportioning, mixing and placement operations. It is used in testing concrete for the

construction of slabs and pavements.

The flexural strength can be determined by the formula

FR= My / I

Procedure:

1. Put the concrete beam into UTM.

2. Record the readings

Observations:

Load =

L =

Width = Height =

Calculations:

Bending Moment = load * L /3 =

Y = D / 2 =

Moment of Inertia = I = bd3 / 12 =

Using Formula Fr = B.M * Y / I =

Page 17: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

17

Practical # 10 : To determine the bending capacity of given steel bars

APPARATUS : UTM , Steel bars

THEORY:

A practical using the method of slices has been developed to calculate the ultimate bending capacity of

reinforced concrete beams and slabs subjected to high bending force.

PROCEDURE:

Based on the analysis of reinforced concrete beams under biaxial bending, an equivalent cross-

section method is proposed to calculate the shear capacity of the beams. According to the two

basic equivalence principles, a biaxial flexural beam is changed into a uniaxial flexural member, and

the shear strength of biaxial flexural beam is calculated as a uniaxial flexural member. Furthermore,

the interrelationships among the equivalent cross-section and the neutral axis inclination as well as

the ratio of depth to width of the cross-section are deduced in advance. The ratios of some typical

cross-section’s equivalent dimensions to its original ones are pointed also. In order to verify the

availability of the equivalent cross-section method, some academic references about the ultimate

strength of biaxial flexural beams are consulted in this paper, and the shear capacity computing

methods by literatures for uniaxial flexural beams are adopted in the strength calculation of biaxial

flexural reinforced concrete simply supported beams with stirrups or without stirrups. The

comparison between the calculation results and experimental results shows that the presented

equivalent cross-section method is feasible and practical which can be used as a reference in

practice design.

RESULT = The bars are elastic in nature and capable of being bent without any fracture and can be used

Page 18: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

18

Practical # 11 : Grading of Coarse Aggregate for an artificial

development of envelop

Apparatus: Mechanical sieve, shaker , Standard sieves of required size in aggregate , balance .

Thoery:

Sieve analysis helps to determine the particle size distribution of the coarse and fine

aggregates.This is done by sieving the aggregates as per IS: 2386 (Part I) – 1963. In this we use

different sieves as standardized by the IS code and then pass aggregates through them and thus

collect different sized particles left over different sieves.

The apparatus used are -

i) A set of IS Sieves of sizes – 80mm, 63mm, 50mm, 40mm,31.5mm, 25mm, 20mm, 16mm,

12.5mm, 10mm, 6.3mm,4.75mm, 3.35mm, 2.36mm, 1.18mm, 600µm, 300µm, 150µm and

75µm.

ii) Balance or scale with an accuracy to measure 0.1 percent of the weight of the test sample.

The weight of sample available should not be less than the weight given below:-

The sample for sieving should be prepared from the larger sample either by quartering or by

means of a sample divider.

Page 19: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

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Procedure to determine particle size distribution of Aggregates. i) The test sample is dried to a constant weight at a temperature of 110 + 5

oC and weighed.

ii) The sample is sieved by using a set of IS Sieves.

iii) On completion of sieving, the material on each sieve is weighed.

iv) Cumulative weight passing through each sieve is calculated as a percentage of the total

sample weight.

v) Fineness modulus is obtained by adding cumulative percentage of aggregates retained on each

sieve and dividing the sum by 100.

Page 20: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

20

Observations :

S.No Sieve Size

(mm)

Wt. Retained

(gms)

Wt. passing

(gms)

% Retained % passing

1

2

3

4

5

6

7

ENVELOP:

S.No Sieve Size

(mm)

Wt. Retained

(gms)

Wt. passing

(gms)

% Retained % passing

1

2

3

4

5

6

7

Page 21: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

21

Practical # 12 : To perform a grading of Fine Aggregates and develop its

grading limit artificially ( zone 1 , zone 2 , zone 3, zone 4)

Apparatus :

Mechanical sieve shaker , balance, oven ,bowl , sieves of required size

Thoery:

To describe an aggregate by its max and minimum size is not enough it has to grade from its

minimum maximum limit. The maximum limit 40 , minimum limit of various types of aggregates in

limit. The different satisfactions by the standard provided limit are known as grading zones.

Procedure:

Take the sample of fine aggregates about 3 kg . Put it on the top of mechanical sieve shaker and

shake it for one minute . This aggregate will pass through different sieves provided in mechanical

sieve shaker. The criteria for sieving is that after completion not more then 1% of the residue on any

individual sieve will pass the sieve during 1 min of with hand sieveing . At end of smaller departure

sized with fine brush. Find the % passing and record it in the table

Page 22: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

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OBSERVATIONS :

S.No Sieve Size

(mm)

Wt. Retained

(gms)

Wt. passing

(gms)

% Retained % passing

1

2

3

4

5

6

7

8

Calculations:

S . NO Sieve Size

( mm)

ZONE – I ZONE – II ZONE – III ZONE-IV

Page 23: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

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23

Practical # 13 : To determine the water absorption of coarse aggregate

APPARATUS : Coarse aggregates

THEORY : This test helps to determine the water absorption of coarse aggregates as

per IS: 2386 (Part III) – 1963. For this test a sample not less than 2000g should be used

PROCEDURE :

i) The sample should be thoroughly washed to remove finer particles and dust,

drained and then placed in the wire basket and immersed in distilled water at a temperature between 22 and 32oC.

ii) After immersion, the entrapped air should be removed by lifting the basket and allowing it to drop

25 times in 25 seconds. The basket and sample should remain immersed for a period of 24 + ½ hrs

afterwards

iii) The basket and aggregates should then be removed from the water, allowed to

drain for a few minutes, after which the aggregates should be gently emptied

from the basket on to one of the dry clothes and gently surface-dried with the

cloth,transferring it to a second dry cloth when the first would remove no further

moisture.The aggregates should be spread on the second cloth and exposed to

the atmosphere away from direct sunlight till it appears to be completely surface-

dry.The aggregates should be weighed (Weight ‘A’).

iv) The aggregates should then be placed in an oven at a temperature of 100 to 110oC for 24hrs. It should then be removed from the oven, cooled and weighed (Weight ‘B’).

Page 24: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

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OBSERVATIONS:

Weight of Aggregates ( Moisture Content ) =

SSD weight of Aggregates :

Over dried Weight of aggregates:

CALCULATIONS:

Using formula = Water absorption = { SSD weight – Over dried weight } / Oven dried weight * 100

Water Absorption =

RESULT :

Water absorption to be (%) =

Page 25: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

PRC- Practical Sir Aneel Kumar

09CE37

25

Practical # 14 : To determine the water absorption of Fine aggregate

APPARATUS : Fine Aggregates

THEORY : Same as Previous practical

PROCEUDRE: Same as Previous practical

OBSERVATIONS:

SSD weight of Aggregates :

Over dried Weight of aggregates:

CALCULATIONS

Using formula = Water absorption = { SSD weight – Over dried weight } / Oven dried weight * 100

Water Absorption =

RESULT:

Water absorption to be (%) =

Page 26: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

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Practical # 15 : Identification of Different Steel bars

APPARATUS : Plain bar and rebar bars

THEORY: There are two types of bars namely Plain and Rebar bars. Those bars which are

smooth in the surface and have no any cuts is said to be Plain bars and they are almost not used

where heavy load is there.

Rebar bars are further divied into 2 types Circular and Zigzag which are also known as deformed

bar . further picture tell the full story of bars.

A rebar (short for reinforcing bar), also known as reinforcing steel, reinforcement steel, or a

deformed bar, is a common steel bar, and is commonly used as a tensioning device in reinforced

concrete and reinforced masonry structures holding the concrete in compression. It is usually

formed from carbon steel, and is given ridges for better mechanical anchoring into the concrete

Observations: Observations are done by seeing the rods.

Page 27: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

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27

Practical # 16 : To perform a Concrete Slump test on 1:2:4 Ratio and

1:1:2 Ratio

APPARATUS :

1. Standard slump cone (100 mm top diameter x 200 mm bottom diameter x 300 mm high) 2. Small scoop 3. Bullet-nosed rod (600 mm long x 16 mm diameter) 4. Rule 5. Slump plate (500 mm x 500 mm) 6. Concrete of 1:2:4 and 1:1:2

MATERIALS FOR 1:2:4 :

F.A =

C.A =

CEMENT =

WATER = W/C ratio =

MATERIALS FOR 1:1:2 :

F.A =

C.A =

CEMENT =

WATER = W/C ratio =

THEORY:

In construction and civil engineering, the Concrete slump test (or simply the slump test) is an in

situ test or a laboratory test used to determine and measure how hard and consistent a given

sample of concrete is before curing.

The concrete slump test is, in essence, a method of quality control. For a particular mix, the

slump should be consistent. A change in slump height would demonstrate an undesired change in

the ratio of the concrete ingredients; the proportions of the ingredients are then adjusted to keep a

concrete batch consistent. This homogeneity improves the quality and structural integrity of the

cured concrete.

Page 28: Plain and Reinforced Concrete Practical 4th Term Dk mamonai

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PROCEDURE:

1. Clean the cone. Dampen with water and place on the slump plate. The slump plate should be clean, firm, level and non-absorbent. Collect a sample of concrete to perform the slum test.

2. Stand firmly on the footpieces and fill 1/3 the volume of the cone with the sample. Compact the concrete by 'rodding' 25 times. Rodding means to push a steel rod in and out of the concrete to compact it into the cylinder, or slump cone. Always rod in a definite pattern, working from outside into the middle.

3. Now fill to 2/3 and again rod 25 times, just into the top of the first layer. 4. Fill to overflowing, rodding again this time just into the top of the second layer. Top up the cone till

it overflows. 5. Level off the surface with the steel rod using a rolling action. Clean any concrete from around the

base and top of the cone, push down on the handles and step off the footpieces. 6. Carefully lift the cone straight up making sure not to move the sample. 7. Turn the cone upside down and place the rod across the up-turned cone. 8. Take several measurements and report the average distance to the top of the sample.If the

sample fails by being outside the tolerance (ie the slump is too high or too low), another must be taken. If this also fails the remainder of the batch should be rejected.

CALCULATIONS FOR 1 :2 : 4 :

CALCULATIONS FOR 1 :1 : 2 :