Objective: Assessment of specific gravity of a specified sample of bitumen
Apparatus
Pycnometer and balance
Theory
Specific gravity of bituminous material is known as the proportion of mass of specified capacity of substance to the equivalent volume of water, temperature of both of them approximating 27 degree Celsius.
Procedure
The specific gravity bottle is first of all thoroughly distilled, cleaned, dried and then weighed. After that, the water is filled in it and massof bottle alongside with water is taken into account. Bituminous material is extensively warmed to pouring temperature and then it is transferred in the vessel up to its one-fourth. After that, the sample is chilled for 30 minutes in air and then once again weight is measured. After that, the water is filled in it and weight is measured once again from the weights taken, the specific gravity of bitumen can be easily ascertained.
Recommended values
The specific gravity of pure bitumen normally extends from 0.97 to 1.02. as per the Indian Standard (BIS) the least specific gravity of paving bitumen at 27°C should be at least 0.99 for grades A25, A35, A45, A65, S35, S45 and S65, 0.98 for A90 and S90 and 0.97 for A200 and S200.
Observations
Weight of empty specific gravity bottle, W1 =
Weight of bottle+bitumen, W2 =
Weight of bottle +water, W3 =
Weight of bottle + water +bitumen, W4 =
Result:
Specific Gravity of Bitumen –