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:

Penetration Test

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.

Ductility Test

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 

stretched bitumen.

Viscosity Test

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.

Spot Test

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

Float Test

The float test is used to measure the consistency of  a  highly  viscous

 bitumen sample.

 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.