Specific Gravity of Bitumen-Definition, Test and Procedure Steps for the Determination

The specific gravity of bitumen is also a must needed test you need to do while your pavement construction. Using this test you can determine the specific gravity of semi-solid bitumen, road tar and anthracite oil.

What is specific gravity?

It is the ratio of the mass of a given volume of bitumen to the mass of an equal volume of water, both taken at a recorded/specified temperature.

You already know that specific gravity test is an important test in your all civil engineering lab. The primary aim of this test is, you can simply convert material weight to volume an vice versa.

For good pavement construction, the range of specific gravity of bitumen should be 0.97-1.10.

According to BIS

A25, A35, A45, A65, S35, S45,S65=0.99

A90 and S90= 0.98

A200 and S200 = 0.97

Apparatus used for the specific gravity of bitumen test

1. Specific gravity bottle of 50ml capacity
2. Water bath
3. Thermometer

How can prepare the sample for this test?

First, you need to clean the bottle very well, then the bitumen is heated about a half hour and then poured into the fresh bottle. Then proceed the below procedure steps to find out specific gravity of bitumen.

Procedure for bitumen specific gravity

1.  The specific gravity bottle along with the stopper is cleaned, dried and weighed the (Weight ‘A’).
2. The specific gravity bottle is filled with freshly boiled distilled water and the stopper is inserted firmly.
   It is kept in the water bath having a temperature of 27.0 + 1oC for not less than half an hour and it is weighed (Weight ‘B’).
3. The specific gravity bottle is weighed about half-filled with the material (Weight ‘C’).
4. The specific gravity bottle is weighed about half-filled with the material and the other half with distilled water (Weight ‘D’).
5. The specific gravity bottle is weighted completely filled with the material (Weight ‘E’).

Calculation of specific gravity of bitumen

1. Specific gravity = (?−?) / (?−?)−(?−?)
   (Solids and semi-solids)
2. Specific gravity = (?−?) / (?−?)
   (Liquids)

The average of the two results should be reported.