BASED ON: Specific gravity and Density of Semi-Solid Bituminous Materials (Pycnometer Method)
For checking Specific gravity of Gilsonite (natural bitumen), there are different methods for example ASTM D3289 or ASTM D70, Here we are going to describe Pycnometer Method that is based on ASTM D70.
This test method covers the determination of the specific gravity and density of semi-solid bituminous materials, asphalt cements, and soft tar pitches by use of a pycnometer.
The suitable picometer is shown in the figure below.
First we completely dry the weighing cubic meter and weigh it (W1), then fill the empty photometer from the water at 25 ° C and weigh it (Ww). Empty the pycnometer and then completely dry it. Then pour some bitumen (about 60 grams) into it and weigh the set (W2). After this step, fill the stopwatch with the marker of distilled water and weigh it (W3); note that bitumen is also present in the stopwatch at this stage.
Another point to consider is that when we use liquid or molten bitumen in this experiment, it is necessary to keep the bitumen in the same state for a long time so that all air bubbles out of it. This test can also be done with semi solid or solid bitumen.
WT = relative density
W1 = mass of pycnometer (plus stopper)
W2 = mass of pycnometer partially filled with asphalt
W3 = mass of pycnometer filled with water