Bitumen Test in civil Engineering
Introducing the Main Bitumen Tests
To determine the properties and quality of bitumen, different tests
are performed on it.
The purpose of performing tests on bitumen is to select the
appropriate bitumen in road construction and various industries.
The most important tests performed on bitumen are:
- Penetration Test
- Softening Point Test
- Ductility Test
- Viscosity Test
- Specific Gravity Test
- Solubility in TCE
- Flash and Fire Point Test
- Loss on Heating Test
- Spot Test
- Drop in Penetration After Heating
- Float Test
For your information, we have prepared the following infographic from Infinity Galaxy to know more about the types of tests that are performed on bitumen:
The penetration indicates the consistency of Bitumen.
This test is performed with the help of a standard laboratory needle
weighing 100 grams.
To perform the test, keep the bitumen sample in a water bath at 25°C.
Let the tip of the needle touch the surface of the sample.
Read the penetration value by releasing the needle within 5 seconds.
Softening Point Test
Bitumen does not have a specific melting point. The softening point
test shows at what temperature bitumen softens.
The ring and ball method is widely used to determine the softening
point of bitumen.
To perform the test, bitumen samples are placed in two rings, and
steel balls are placed on them. Put the set in a hot water bath. Report
the temperature at which the steel balls pass through the softened
bitumen and reach the bottom of the beaker.
In this test, the standard sample is elongated at a certain speed and
temperature. Ductility is the length in centimeters before the tear of a
The viscosity test measures the bitumen resistance to flow. The
viscosity of bitumen is measured with the help of a viscometer.
In this test, the time required for a certain volume of the
sample to pass through the calibrated tube is recorded.
Viscosity is measured by multiplying the viscometer calibration
coefficient by the time.
Usually, the viscosity test is performed at two different temperatures,
60°C and 135°C.
Specific Gravity Test
A specific gravity test is used to detect bitumen impurities. This test
measures the ratio of lighter or heavier bitumen to water in the same
The pycnometer method, and the Balance method, are two methods
for calculating specific gravity.
Solubility in TCE
Bitumen purity can be determined using the bitumen solubility test.
The method of performing this test is that bitumen must first be
dissolved in trichloroethylene. Pass the mixture through the filter.
After washing the insoluble material, let it dry.
The percentage of insoluble materials is obtained by dividing the mass
of insoluble materials by the mass of the bitumen sample.
Flash and Fire Point Test
Flash and fire point is the lowest temperature at which the material is
at risk of catching fire.
For Cleveland, open cup tester, heat the cup full of bitumen samples.
At the flash point temperature, the sample vapor is fired. The fire point
can be found by continuing to heat the sample until a flame appears
above it. The flame should last at least 5 seconds.
Loss on Heating Test
To determine the volatile component of bitumen, the loss on heating
test is used. To perform this test, 50 grams of bitumen sample is
heated at a temperature of 163 degrees Celsius. Then the percentage
of heat loss is measured by measuring the mass of the sample before
and after heating.
The bitumen spot test indicates whether the bitumen has been
damaged by excessive heat during processing or not.
In this test, dissolve about 2 grams of bitumen in 10 ml of solution.
Place a small drop of the solution on a filter paper. If the spot is
brown, the test is successfully negative, which means that there are
no additives in the bitumen. If the formed spot is brown with a black
center, the test is successfully positive, which means that the bitumen
contains some additives.
Drop in Penetration After Heating
Penetration loss on heating test measures the hardness of bitumen
after heating and the percentage of volatile bitumen components. In
this test, apply a needle weighing 100 grams to the bitumen sample
for 5 seconds. Keep the bitumen sample at 163°C for 5 hours
And repeat the test again.
Drop in penetration value=(difference between 2 amount of penetration/initial amount) * 100
The float test is used to measure the consistency of a highly viscous
In this test, screw the heated bitumen sample inside the collar to the
alumina float. First, float the whole assembly in a water bath with a
temperature of 5 degrees. Then transfer it to a water bath with a
temperature of 50 degrees.
Record the time when water begins to flow through the material.