Bitumen Density
The ratio of the weight of a substance to its volume is called its
specific weight. However, density is the ratio of the mass of a substance to
its volume. Density is independent of the gravity acceleration, nevertheless,
the specific weight is affected by the gravity acceleration of the earth.
Calculating the weight of bitumen inside the reservoirs and
tankers in the road construction sites which is restored in terms of volume is
among the main reasons to know the bitumen density. The bitumen density
measurement test is carried out on the basis of the ASTM D70 standard. In fact,
the specific weight (density) of each substance is an interface between its
weight (mass) and volume. The bitumen density calculation is carried out
on the basis of Archimedes’ principle.
In accordance with the definition of bitumen density, the ratio of
the mass of a definite volume of bitumen to the water of the same volume at a known
temperature.
Nickle Crucible and pycnometer are among the common methods in
calculating the specific weight of bitumen (bitumen density).
The amount of bitumen mentioned in the related calculations means
its weight, while bitumen is practically measured on the basis of its volume.
On the other hand, considering that bitumen is always heated so that it can be
used and its volume changes in the reservoir, it is important to know the
coefficient of bitumen’s thermal expansion. Therefore, its specific weight is
always considered at a definite temperature and on the basis of the test
method.
The test method on the basis of the ASTM D70 standard is as
follows:
Bitumen Density Test Objective:
The objective of this test is to determine the specific weight and
density of special bitumens and semi-solid bituminous materials through the pycnometer
method.
Bitumen Density Test
Description:
At first, fill a 600 mm beaker with distilled water and immerse the
beaker into a water bath, i.e. the top of the beaker must be above the water
level in the bath. Dry the pycnometer and weight with the precision of 1 mg and
write down the number. Take the beaker out of the bath and fill the pycnometer
with distilled water and place its lid loosely on the pycnometer. Then, put the
pycnometer inside the beaker and close its lid. Let the pycnometer be filled
with water and the extra water come out of the hole on top of it. Take out the
pycnometer filled with water from the beaker and dry it. Then, weight it and
write down the number. Empty the pycnometer and dry it. Fill three-quarters of
the pycnometer volume with the sample. Afterward, weight it after cooling, and
write down the weight. Finally, place the pycnometer containing the sample
inside the beaker and let its remaining volume to be filled with distilled
water. Afterward, take out the pycnometer from the beaker, dry it, weight it
using a scale. Use the standard formula of this test for calculating its
density and calculate the density.