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Determining Softening Point Of Bitumen

Determining Softening Point Of Bitumen

This test is done to determine the softening point of asphaltic bitumen and fluxed native asphalt, road tar, coal tar pitch and blown type bitumen as per IS: 1205 – 1978. The principle behind this test is that softening point is the temperature at which the substance attains a particular degree of softening under specified condition of the test.

The apparatus required for this test :-
i) Ring and ball apparatus
ii) Thermometer – Low Range : -2 to 80oC, Graduation 0.2oC – High Range : 30 to 200oC, Graduation 0.5oC

i) The sample should be just sufficient to fill the ring. The excess sample should be cut off by a knife.

ii) Heat the material between 75 and 100oC. Stir it to remove air bubbles and water, and filter it through IS Sieve 30, if necessary.

iii) Heat the rings and apply glycerine. Fill the material in it and cool it for 30 minutes.

iv) Remove excess material with the help of a warmed, sharp knife.


Procedure to determine Softening Point Of Bitumen
A) Materials of softening point below 80o C:


i) Assemble the apparatus with the rings, thermometer and ball guides in position.

ii) Fill the beaker with boiled distilled water at a temperature 5.0 ± 0.5oC per minute.

iii) With the help of a stirrer, stir the liquid and apply heat to the beaker at a temperature of 5.0 ± 0.5oC per minute.

iv) Apply heat until the material softens and allow the ball to pass through the ring.

v) Record the temperature at which the ball touches the bottom, which is nothing but the softening point of that material.

B) Materials of softening point above 80oC:
The procedure is the same as described above. The only difference is that instead of water, glycerine is used and the starting temperature of the test is 35oC.

Record the temperature at which the ball touches the bottom.

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Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

15 comments on "Determining Softening Point Of Bitumen"




A bit helpful, a bit more explanatory detail would be welcome

akash singh says:

what is the objectine of this softening test and uses and application of results of the test?

madan s ambulgekar says:

softenig test is done for the bitumen because while using on pavement it should not start to softening at normal temp.of that region i.e. not below 47 degree temp. for this softening point test is done.

madan s ambulgekar says:

when vechiles runs on the road htat time if bitumen becomes soft ,vechicles will not run on the as per rhe temp.grade of bitumen is used.

syed saifullah shah says:

that’s nice a little more when the softening is more then when car moves on the road it creates ruts.the phenomenon is called as rutting.

eva mahyddin says:

Is the same asphalt has same softening point and penetration in different places and different climate? thanks

Arito says:

so helpful. thanks

Mani@Vasu says:

Various grade of bitumen conduct the test. So how many values of various grade bitumen/tar

Innocent says:

I am looking for standard test methods (lab and field) to test for the adhesion properties of bitumen, please help

Marc says:

I am interested to know what o-ring elastomer one might use to seal Hot bitumen/asphalt. Could anyone help?

iz says:

two test temperatures differ by more than 1’c, offer an explanation

sandhyarani.p says:

sir,I got the softening point of bitumen in the lab as 44 degrees,and i came to know that softening point range is 35-70 how can i declare the nature of this bitumen,whether it is good?bad?or satisfactory?

Mbali Mbali XUXU says:

Sir, how to do calculations for Softening Point ofBitumen?


Assalam o Alikum.very very nice. Allah BLESS you

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