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Determine initial and final setting time of the given sample

Aim:

To determine the initial and final setting times for the given sample of cement.

Equipments Required:

Vicat apparatus (conforming to IS: 5513-1976) with attachments.
Standard balance
Gauging trowel.
& brush.

Theory:

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 :

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.
Potable or distilled water shall be used in preparing the paste.
The paste shall be gauged in the manner and under the conditions prescribed in determination of consistency of standard cement paste.
Start a stop-watch at the instant when water is added to the cement.
Fill the mould with the cement paste gauged as above the mould resting on a nonporous plate.
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.

Preparation of Test Block :

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.
Potable or distilled water shall be used in preparing the paste.
The paste shall be gauged in the manner and under the conditions prescribed in determination of consistency of standard cement paste.
Start a stop-watch at the instant when water is added to the cement.
Fill the mould with the cement paste gauged as above the mould resting on a nonporous plate.
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 :

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.
In the beginning, the needle will completely pierce the test block.
Repeat this procedure until the needle, when brought in contact with the test block and released as described above, fails to pierce the block 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 :

Replace the needle of the Vicat apparatus by the needle with an annular attachment.
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.
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.

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 ^oC ± 20 ^oC.
Care shall be taken to keep the needle straight.

Observations :

Sl.No	Time in ( min )	Penetration depth ( mm )
1.
2.
3.

Result:

Initial setting time of the given sample of cement is = __________

Final setting time of the given sample of cement is = __________

Viva Questions:

Define initial setting time of cement ?
Define final setting time of cement ?

Determination of fineness of given sample of cement

Aim:

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

Equipments Required:

IS-90 micron sieve conforming to IS: 460-1965
Standard balance
Measuring jar.
Weighing balance
& brush.

Theory:

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.

Procedure:

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

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 :

Sl.No	Weight of sasmple ( gms )	Weight of residue ( gms )	Fineness ( % )
1.
2.
3.

Result:

Fineness of the given sample of cement is = __________

Viva Questions:

Define fineness of cement ?
What is the sieve size used in fineness of cement ?

Normal consistency of cement sample

Aim:

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

Equipments Required:

Vicat apparatus (conforming to IS: 5513 - 1976) with plunger (10 mm in diameter) balance.
Weights.
Gauging trowel.

Theory:

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:

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.
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.
The gauging time shall be counted from the time of adding the water to the dry cement until commencing to fill the mould.
Fill the vicat mould with this paste, the mould resting upon a non porous plate.
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.
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.
This operation shall be carried out immediately after filling the mould.
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 ^oC.
For each repetition of the experiment fresh cement is to be taken.

Observations :

Sl.No	Consistency of cement ( % by weight )	Weight of cement taken ( g )	Weight of water taken ( ml )	Plunger penetration ( mm )
1.
2.
3.
4.
5.
6.
7.

Result:

Normal consistency of the given sample of cement is = __________

Viva Questions:

Define normal consistency of cement ?
What is the name of apparatus used testing of normal consistency of cement ?

Specific gravity of cement | viva questions | civil engineering

Specific gravity of cement viva questions and answeres.

viva questions and answeres.

1. Define specific gravity of cement ?

The specific gravity of cement is the ratio of the weight of a given volume of cement to the weight of an equal volume of water.

2. What are the factors affecting the specific gravity of cement ?

Factors affecting specific gravity of cement are

Materials used in manufacture of cement like limestone, shells, chalk, shale, clay, slate, blast furnace slag, silica sand, and iron ore.
Humidity.
Moisture content
Temperature and Pressure.

3. Why is kerosene used instead of water in the specific gravity test ?

Cement reacts with water in exothermic reaction forming calcium silicate hydrate (C-S-H) and calcium hydroxide ca(OH)₂. The cement reaction with water hinders the accuracy of the test. Hence, cement specific gravity is determined with reference to a non-reactive liquid like kerosene or diesel.

4. What is the use of specific gravity of cement ?

The specific gravity test is used in quality assessment of cement. Specific gravity of some deleterious materials will be low which is unsuitable for used in concrete mix. The high moisture containing cement will have high specific gravity which also unsuitable for application in building.

5. Is specific gravity of cement constant ?

Specific gravity varies from the time of production to application in structures. When the cement bag is exposed to air containing moisture, its specific gravity goes on increasing. The finer cement particles absorb water from air and solidify.

6. List the apparatus used in specific gravity of cement test ?

The apparatus used in specific gravity of cement are Le-Chatelier Flask, trowel, measuring jar, weighing balance, plate, rubber glove and kerosene.

7. If the air bubbles are not completely removed from the flask, how the results will be affected ?

Cement contains finely grained particles of micron size. Air gets entrapped between these particles, completely removing from the flask is impossible. The entrapped air will result in error measurement of equal volume of cement and kerosene.

8. Why is it necessary to keep the temperature of test chamber constant during this experiment ?

Cement is made up of like limestone, shells, chalk, shale, clay, slate, blast furnace slag, silica sand, and iron ore. These materials volume will be different for different temperature and pressure. Maintaining a constant temperature and pressure is necessary to ensure the consistency of test.

9. What are precautions need to be taken while performing specific gravity cement test?

Only kerosene which is free of water is to be used.
All air bubbles shall be eliminated in filling the apparatus and inserting the stopper.
Weighing is to be done quickly after filling the apparatus and shall be accurate to 0.1 mg.
Precautions are to be taken to prevent expansion and overflow of the contents resulting from the heat of the hand when wiping the surface of the apparatus.

Question and answer on specific gravity of cement

Refrence

1. Brooks, J.J & Neville A. M. (2019). Concrete Technology (2^nd ed.). Pearson Publishers Pvt Ltd. click here

2. Shetty, M. S & Jain, A. K. ( 2018). Concrete Technology: Theory And Practice (8^thed.).S Chand Publishers Pvt Ltd.

Web based calculator for compressive strength of concrete cube | concrete technology lab manual

Web based calculator for compressive strength of concrete cube

Compressive strength of concrete cube.

Theory and Computations: This page exhibits online editable lab manual for compression testing of concrete cube. The dimensions like length and breadth of cube are noted down in millimetre. The compression strength of concrete cube is evaluated by dividing failure load to loaded area of cube. The result will be exhibited in MPa.

Calculator tab: The calculator tab consists of editable page and online calculator for compressive strength of concrete cube. In this concrete cube data can be entered for 7, 14, 21, and 28 days, This page calculates average compressive strength from the provided input values. A graph of compression strength vs curing days will be plotted for better understanding of quality of concrete.

calculator for compressive strength of cube concrete

Determination of compressive strength of cube concrete Specimens

Aim:

To determine the cube compressive strength of the specified concrete mix proportion.

Reference Indian standard codes:

IS: 516-1959.
IS: 1199-1959.
SP: 23-1982.
IS: 10086-1982.

Equipment's Required:

Compression testing Machine: The testing machine may be of any reliable type, of sufficient capacity for the tests and capable of applying the load at the rate of 14 N/mm² per minute. The permissible error shall be not greater than ± 2 percent of the maximum load.
Cube moulds:The mould shall be of 150 mm size conforming to IS: 10086-1982.
Weighing balance.
Tamping rod.
Rubber gloves.
Metallic sheet.
Demoulding oil.

Theory:

One of the important properties of concrete is its strength in compression. The strength in compression has a definite relationship with all other properties of concrete i.e. these properties improved with the improvement in compressive strength. With this test we can estimate concrete quality. The cubical moulds of size 15cm x 15cmx 15 cm are used for finding compresion strength. The concrete is prepared with definite proportion is poured in the mould and tempered with tamping rod to minimize air voids. After 24 hours these moulds are removed and test specimens are put in water for curing. The top surface of this specimen should be made even and smooth. This is done by putting cement paste and spreading smoothly on whole area of specimen. These specimens are tested by compression testing machine after 7 ,14 21 and 28 days curing. Load should be applied gradually at the rate of 14 N/mm² per minute till the Specimens fails. Load at the failure divided by area of specimen gives the compressive strength of concrete. At least three specimens are tested at each selected age. Equation for compressive strength of cube, σ_cube is

\[\mathop \sigma \nolimits_{cube} = \frac{F}{A}\]

Where,

σ_cube = Compressive strength of cube (N/mm² Or MPa).
F = Failure load (N).
A = Loaded area of cube (mm²).

Procedure:

Sampling of Materials : Samples of aggregates for each batch of concrete shall be of the desired grading and shall be in an air-dried condition. The cement samples, on arrival at the laboratory, shall be thoroughly mixed dry either by hand or in a suitable mixer in such a manner as to ensure the greatest possible blending and uniformity in the material.
Proportioning : The proportions of the materials, including water, in concrete mixes used for determining the suitability of the materials available, shall be similar in all respects to those to be employed in the work.
Weighing : The quantities of cement, each size of aggregate, and water for each batch shall be determined by weight, to an accuracy of 0.1 percent of the total weight of the batch.
Mixing Concrete : The concrete shall be mixed by hand, or preferably, in a laboratory batch mixer, in such a manner as to avoid loss of water or other materials. Each batch of concrete shall be of such a size as to leave about 10 percent excess after moulding the desired number of test specimens.
Mould : Test specimens cubical in shape shall be 15x15x15 cm. If the largest nominal size of the aggregate does not exceed 2 cm, 10 cm cubes may be used as an alternative. Cylindrical test specimens shall have a length equal to twice the diameter.
Compacting : The test specimens shall be made as soon as practicable after mixing, and in such a way as to produce full compaction of the concrete with neither segregation nor excessive laitance.
Curing - The test specimens shall be stored in a place, free from vibration, in moist air of at least 90 percent relative humidity and at a temperature of 27° ± 2°C for 24 hours ± ½ hour from the time of addition of water to the dry ingredients.
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 specimen which are to be in contact with the compression platens.
In the case of 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 platen. No packing shall be used between the faces of the test specimen and the steel platen of the testing machine.
The load shall be applied without shock and increased continuously at a rate of approximately 140 kg/cm²/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.

Observations:

Sl.No.	Description.	Particulars.
1.	Type of cement.
2.	Specific gravity of cement.
3.	Type of sand.
4.	Specific gravity of sand.
5.	Fineness modulus of sand.
6.	Type of coarse aggregates.

Concrete mix proportions:

Sl.No.	Description.	Proportion for 1m³.	Proportion for batch mixing.
1.	Cement (Kg).
2.	Coarse aggregates (Kg).
3.	Fine aggregates (Kg).
4.	water (Kg).
5.	Aggregate/Binder ratio.
6.	Water/Cement ratio.
7.	Admixture.

Compression test data sheet:

Specimen No.	Days Cured.	Length of cube mm.	Breadth of cube mm.	Area mm².	Load kg.	Load N.	Stress MPa.
1.	7
2.	7
3.	7
Average :
4.	14
5.	14
6.	14
Average :
7.	21
8.	21
9.	21
Average :
10.	28
11.	28
12.	28
Average :

Conclusion:

The average 7 Days Compressive Strength of concrete = ____________.
The average 14 Days Compressive Strength of concrete = ____________.
The average 21 Days Compressive Strength of concrete = ____________.
The average 28 Days Compressive Strength of concrete = ____________.

Viva Questions:

What is the effect of W/C ratio on compressive strength of concrete ?
Mention the factors affecting the compressive strength of concrete ?
What is the effect of increasing rate of loading on cube ?
How does workability of concrete affects strength of concrete ?
What is the relation between compresive strength and flexural strength oncrete ?

Determination of compressive strength of cube concrete Specimens

Aim:

To determine the cube compressive strength of the specified concrete mix proportion.

Reference Indian standard codes:

IS: 516-1959.
IS: 1199-1959.
SP: 23-1982.
IS: 10086-1982.

Equipment's Required:

Compression testing Machine: The testing machine may be of any reliable type, of sufficient capacity for the tests and capable of applying the load
at the rate of 14 N/mm² per minute. The permissible error shall be not greater than ± 2 percent of the maximum load.
Cube moulds:The mould shall be of 150 mm size conforming to IS: 10086-1982.
Weighing balance.
Tamping rod.
Rubber gloves.
Metallic sheet.
Demoulding oil.

Theory:

\[\mathop \sigma \nolimits_{cube} = \frac{F}{A}\]

Where,

σ_cube = Compressive strength of cube (N/mm² Or MPa).
F = Failure load (N).
A = Loaded area of cube (mm²).

Procedure:

Sampling of Materials : Samples of aggregates for each batch of concrete shall be of the desired grading and shall be in an air-dried condition. The cement samples, on arrival at the laboratory, shall be thoroughly mixed dry either by hand or in a suitable mixer in such a manner as to ensure the greatest possible blending and uniformity in the material.
Proportioning : The proportions of the materials, including water, in concrete mixes used for determining the suitability of the materials available, shall be similar in all respects to those to be employed in the work.
Weighing : The quantities of cement, each size of aggregate, and water for each batch shall be determined by weight, to an accuracy of 0.1 percent of the total weight of the batch.
Mixing Concrete : The concrete shall be mixed by hand, or preferably, in a laboratory batch mixer, in such a manner as to avoid loss of water or other materials. Each batch of concrete shall be of such a size as to leave about 10 percent excess after moulding the desired number of test specimens.
Mould : Test specimens cubical in shape shall be 15x15x15 cm. If the largest nominal size of the aggregate does not exceed 2 cm, 10 cm cubes may be used as an alternative. Cylindrical test specimens shall have a length equal to twice the diameter.
Compacting : The test specimens shall be made as soon as practicable after mixing, and in such a way as to produce full compaction of the concrete with neither segregation nor excessive laitance.
Curing - The test specimens shall be stored in a place, free from vibration, in moist air of at least 90 percent relative humidity and at a temperature of 27° ± 2°C for 24 hours ± ½ hour from the time of addition of water to the dry ingredients.
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 specimen which are to be in contact with the compression platens.
In the case of 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 platen. No packing shall be used between the faces of the test specimen and the steel platen of the testing machine.
The load shall be applied without shock and increased continuously at a rate of approximately 140 kg/cm²/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.

Observations:

Sl.No.	Description.	Particulars.
1.	Type of cement.
2.	Specific gravity of cement.
3.	Type of sand.
4.	Specific gravity of sand.
5.	Fineness modulus of sand.
6.	Type of coarse aggregates.

Concrete mix proportions:

Sl.No.	Description.	Proportion for 1m³.	Proportion for batch mixing.
1.	Cement (Kg).
2.	Coarse aggregates (Kg).
3.	Fine aggregates (Kg).
4.	water (Kg).
5.	Aggregate/Binder ratio.
6.	Water/Cement ratio.
7.	Admixture.

Compression test data sheet:

Specimen No.	Days Cured.	Length of cube mm.	Breadth of cube mm.	Load kg.
1.	7	150.2	150	11100
2.	7	150.1	150.3	11000
3.	7	150.0	150.1	11200
Average :
4.	14	150.1	150.2	12100
5.	14	150	150	12200
6.	14	150.1	149.9	12300
Average :
7.	21	150.1	150.2	13100
8.	21	150	150.1	13250
9.	21	150.1	150	13210
Average :
10.	28	150.3	150.2	14100
11.	28	150.1	150.0	14200
12.	28	150	149.9	14300
Average :

Graph:

Conclusion:

The average 7 Days Compressive Strength of concrete = MPa.
The average 14 Days Compressive Strength of concrete = MPa.
The average 21 Days Compressive Strength of concrete = MPa.
The average 28 Days Compressive Strength of concrete = MPa.

Web based calculator for compressive strength of concrete cube

1. First video

2. Second video

3. Third video

Refrence

1. Brooks, J.J & Neville A. M. (2019). Concrete Technology (2^nd ed.). Pearson Publishers Pvt Ltd.

2. Shetty, M. S & Jain, A. K. (2018). Concrete Technology: Theory And Practice (8^thed.).S Chand Publishers Pvt Ltd.

3. Irving, K. (2009). Engineered Concrete, Mix design and test methods (2^nd ed.). CRC press, Taylor & Francis group.

Calculator for specific gravity of cement

calculator for specific gravity of cement

Specific gravity of cement

CT lab manual

Determination of specific gravity of given sample of cement

Aim:

Determination of specific gravity of cement as per IS 4031-(Part 11)-1988.

Equipments Required:

Le-Chatelier Flask (Specific gravity bottle).
Trowel.
Measuring jar.
Weighing balance
Other accessories.
Plate
Rubber glove.

Theory:

The specific gravity of cement is the ratio of the weight of a given volume of substance to the weight of an equal volume of water. It is a number and denotes how many times a substance is heavy as water. To find the specific gravity of cement, it is required to find the weight of a certain volume cement and the weight of an equal volume of water. As cement reacts with water its specific gravity is determined with reference to a non-reactive liquid like kerosene. The specific gravity of ordinary portland cement is generally around 3.15. Equation for specific gravity, G is

\[G = \frac{{\left( {\mathop W\nolimits_2 - \mathop W\nolimits_1 } \right) \times \left( {\mathop W\nolimits_4 - \mathop W\nolimits_1 } \right)}}{{\left[ {\left( {\mathop W\nolimits_4 - \mathop W\nolimits_1 } \right) - \left( {\mathop W\nolimits_3 - \mathop W\nolimits_2 } \right)} \right] \times \left( {\mathop W\nolimits_5 - \mathop W\nolimits_1 } \right)}}\]

Where,

W₁ = Weight of empty dry bottle in grams.
W₂ = Weight of bottle + cement in grams.
W₃ = Weight of bottle + Cement + Kerosene in grams.
W₄ = Weight of bottle + Full Kerosene.
W₅ = Weight of bottle + Full Water.

Precautions:

Only kerosene which is free of water is to be used.
All air bubbles shall be eliminated in filling the apparatus and inserting the stopper.
Weighing is to be done quickly after filling the apparatus and shall be accurate to 0.1 mg.
Precautions are to be taken to prevent expansion and overflow of the contents resulting from the heat of the hand when wiping the surface of the apparatus.

Procedure:

Clean and dry the specific gravity bottle and weigh it with the stopper is taken as, (W₁ in gm).
Fill the specific gravity bottle with cement sample at least half of the bottle and weigh with stopper is taken as, (W₂ in gm).
Fill the specific gravity bottle containing the cement, with kerosene (free of water) placing the stopper and weigh it (W₃ in gm) ,While doing this do not allow any air bubbles to remain in the specific gravity bottle. (W₃ in gm).
After weighing the bottle, the bottle shall be cleaned and dried again.
Then fill it with fresh kerosene and weigh it with stopper is taken as, (W₄ in gm).
Remove the kerosene from the bottle and fill it with full of water and weigh it with stopper is taken as, (W₅ in gm).

Table:

Sl.No	Particulars	Test No.1	Test No.2	Test No.3
1.	Weight of empty dry bottle (W₁), gm
2.	Weight of bottle + cement (W₂), gm
3.	Weight of bottle + Cement + Kerosene (W₃), gm
4.	Weight of bottle + Full Kerosene (W₄), gm
5.	Weight of bottle + Full Water (W₅), gm.
6.	Specific gravity, G
5.	Average G = (G₁+G₂+G₃)/3

Result:

Average, G=

Verification/ Validation:

The specific gravity of ordinary portland cement is around 3.15. If the difference between the three tests differ by more than 0.03, the test shall be repeated.

Conclusion:

Specific gravity of the given cement obtained as ___________.

Viva Questions:

Define specific gravity.
Why is kerosene used instead of water in the specific gravity test.
What is the use of specific gravity of cement ?
Is specific gravity of cement constant ?
Name the factors affecting the specific gravity of cement.

Determination of specific gravity of given sample of cement

Aim:

Determination of specific gravity of cement as per IS 4031-(Part 11)-1988.

Equipments Required:

Le-Chatelier Flask (Specific gravity bottle).
Trowel.
Measuring jar.
Weighing balance
Other accessories.
Plate
Rubber glove.

Theory:

Where,

W₁ = Weight of empty dry bottle in grams.
W₂ = Weight of bottle + cement in grams.
W₃ = Weight of bottle + Cement + Kerosene in grams.
W₄ = Weight of bottle + Full Kerosene.
W₅ = Weight of bottle + Full Water.

Precautions:

Only kerosene which is free of water is to be used.
All air bubbles shall be eliminated in filling the apparatus and inserting the stopper.
Weighing is to be done quickly after filling the apparatus and shall be accurate to 0.1 mg.
Precautions are to be taken to prevent expansion and overflow of the contents resulting from the heat of the hand when wiping the surface of the apparatus.

Procedure:

Clean and dry the specific gravity bottle and weigh it with the stopper is taken as, (W₁ in gm).
Fill the specific gravity bottle with cement sample at least half of the bottle and weigh with stopper is taken as, (W₂ in gm).
Fill the specific gravity bottle containing the cement, with kerosene (free of water) placing the stopper and weigh it (W₃ in gm) ,While doing this do not allow any air bubbles to remain in the specific gravity bottle. (W₃ in gm).
After weighing the bottle, the bottle shall be cleaned and dried again.
Then fill it with fresh kerosene and weigh it with stopper is taken as, (W₄ in gm).
Remove the kerosene from the bottle and fill it with full of water and weigh it with stopper is taken as, (W₅ in gm).

Table:

Sl.No	Particulars	Test No.1	Test No.2	Test No.3
1.	Weight of empty dry bottle (W₁), gm	57	57.1	57.05
2.	Weight of bottle + cement (W₂), gm	107	107.1	106.9
3.	Weight of bottle + Cement + Kerosene (W₃), gm	174	174.1	173.9
4.	Weight of bottle + Full Kerosene (W₄), gm	136	136.1	136.2
5.	Weight of bottle + Full Water (W₅), gm.	157	157.1	156.9
6.	Specific gravity, G
5.	Average G = (G₁+G₂+G₃)/3

Result:

Average, G=

Verification/ Validation:

The specific gravity of ordinary portland cement is around 3.15. If the difference between the three tests differ by more than 0.03, the test shall be repeated.