Loss on Heating Test of Bitumen

The loss on heating test determines the volatile component of bitumen. 

To perform this test, 50 g of bitumen sample is heated in the oven at 163 degrees Celsius. Then the amount of bitumen mass loss is determined.

What is the Significance of the Loss on Heating Test of Bitumen

The loss on heating test measures the mass of volatile content in bitumen. This amount is important in the industry, especially in the paving industry. 

A bitumen with a high amount of loss on heating will be hardened. As a result, it becomes less flexible and brittle. Thus, if such a bitumen binder is used in pavement, the asphalt cannot endure load and temperature changes. As a result, asphalt quality is reduced.

Bitumen binder for pavement constructions must have a loss on heating up to 1 percent. The case of bitumen with a penetration of 150 to 200 can have up to 2 % loss on heating.

Read More about 11 important Bitumen Tests

International Standard Methods for Loss on Heating Test of Bitumen 

For bitumen, the following methods can be used to measure loss on heating:

• ASTM D6
• ASTM D1754
• IS 1212
• AASHTO T 47
• AASHTO T179
• EN 13303

Apparatus and Procedure of Loss on Heating Test of Bitumen Based on ASTM D 6

- Component of apparatus

• Oven
• Digital balance
• Thermometer
• Metal or glass container

- Test steps

1- Sample preparation 

Stir the waterless bitumen well until it becomes smooth. 

If the sample is solid, heat it to become liquid so that it can be easily transferred into the container. Make sure that the temperature is not too high because the component will change, and the test will be failed.

2- Procedure

Put 50 g of sample into the container. If the sample was heated, let it cool at room temperature before weighing.

For 5 hours, place the container of bitumen sample in the oven at 163 degrees Celsius. 

Then remove the sample from the oven and let it cool at room temperature. After it cools, weigh it.

The amount of loss on heating is calculated as follows:

Loss on heating (%) = [(Initial weight – Final weight)/Initial weight]*100