Procedure:

• i) When the bitumen is heated it loses the volatility and gets hardened. About 50gm of the sample is weighed and heated to a temperature of 1630C for 5hours in a specified oven designed for this test.
• ii) The sample specimen is weighed again after the heating period and loss in weight is expressed as percentage by weight of the original sample.
• iii) Bitumen used in pavement mixes should not indicate more than 1% loss in weight, but for bitumen having penetration values 150-200 up to 2% loss in weight is allowed.