Specific Gravity of Cement | Specific Gravity Test on Cement

What Is the Specific Gravity of Cement

The specific gravity of cement is defined as the mass of cement of a specified volume to the mass of water of the same volume of cement.

It can also be defined as the density of cement to the density of water for the same volume.

In both, the definitions of the volume of cement must be the same. If the volume does not remain the same then the specific gravity value may be accurate.

Because the mass and density of cement and water are liable to change with respect to their volume.

Specific gravity is the comparison of the mass or density of any substance with the mass or density of the standard substance. Generally, water is considered the standard substance.

The best method to determine the specific gravity of cement is by using a liquid such as water-free kerosene, which does not react with cement.

For conducting this test, a standard Le Chatelier specific gravity flask or specific gravity bottle may be employed.

The Le Chatelier specific gravity flask is also utilized to determine the specific gravity of dust, sand, and other fine materials.

This specific gravity of cement is an essential parameter in concrete mix design material quantity calculations.

This specific gravity of portland cement is about 3.15 and can be measured using ASTM C188.

Read More: Initial And Final Setting Time Of Cement Test, Procedure & Result

Different Tests of Cement

The following tests are conducted on cement,

1. Fineness Test of Cement
2. Consistency Test of Cement
3. Setting Time Test of Cement
4. Soundness Test of Cement
5. The Heat of Hydration Test
6. Specific Gravity Test of Cement
7. Tensile Strength Test
8. Chemical Composition Test

Use of Cement Specific Gravity

The specific gravity value of any substance gives the idea of how heavy or light is the substance compared to the standard substance. From the value, we can judge whether it will float or sink into another substance.

All-natural material and substance have their own specific gravity value. It generally ranges from 1 to 100.

Water has a specific gravity of around 1and If the specific gravity of other material is greater than 1, then it sinks in water.

If the specific gravity of the material is less than 1 it floats in water. Therefore, the specific gravity of any material is an important property to know. So that we can use it in a proper way.

Generally, the specific gravity of cement ranges from 3.1 to 3.16 g/cc. From this, we can say that the specific gravity of cement is more than the specific gravity of water is 1.

It means cement will sink in water if we put it in the water. Also, we can say that cement is heavier than water.

Cement particle has pore in them and they can absorb moisture from the atmosphere. Considering this behavior of cement particles the specific gravity can either increase or decrease.

While we are calculating cement for mix design we consider the specific gravity of cement as standard 3.14.

So, any change in cement-specific gravity will affect the mix design. Hence, it is essential to test the specific gravity of the cement procured before the mixing process.

This is the main reason behind we reject the old stored cement. Old cement has more liable to store external moisture which results in increased specific gravity of cement.

Read More: Consistency Test Of Cement Test, Calculation & Result

Specific Gravity of Cement Test

IS code for the Specific gravity test is IS 2720- Part 3

Apparatus

The following apparatus is used in specific gravity tests of cement,

Specific Gravity of Cement Procedure

• Clean the Lechatlier flask before use. It should be free from moisture.
• Now, Take the weight of the empty flask as W1.
• Take around 50 gm of cement and fill in the flask.
• Fix the stopper on the flask and weigh the flask with cement as W2.
• Now fill the kerosene in the flask up to the neck of the bottle.
• Thoroughly mix cement and kerosene in the flask taking care no air bubble is left in it. Record this weight as W3.
• Empty the flask and clean it. Now fill the kerosene in it up to the neck of the bottle and record the weight as W4.

Read More: Fineness Test Of Cement Procedure And Importance

Observations and Calculations

The specific gravity of the cement formula is as follows,

= (W2 – W1) / ((W2 – W1) – (W3 – W4) X 0.79)

Where,

W1 = Weight of Empty Flask.

W2 = Weight of Flask + Cement.

W3 = Weight of Flask + Cement + Kerosene.

W4 = Weight of Flask + Kerosene.

Here, the specific gravity of kerosene is 0.79g/cc

Note:

Conduct tests at least 3 times for accurate results.

Clean the flask before using it again.

Result

The specific gravity of a sample of cement = 3.15

Read More: Fineness Test Of Cement Procedure And Importance

Why is Kerosene used for the Specific Gravity Test of Cement?

If we use water instead of kerosene, water will mix with cement and make a paste. As we know when cement is mixed with water, cement starts its heat of the hydration process. So, water can’t be used for cement-specific gravity tests.

Kerosene is a very well-known polar liquid so it will not react with cement while doing the test. The specific gravity of kerosene is 0.79g/cc.

FAQs:

Watch Video: Specific Gravity Test of Cement

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