Loss on Heat/Thin Film Oven

A Loss on Heat/Thin Film Oven (TFOT) is a highly specialized laboratory device designed to assess the aging characteristics of bitumen and other binders used in road construction when subjected to prolonged exposure to heat and air. This testing method is crucial in determining how asphalt materials will change during the production, storage, and application processes, helping engineers predict potential performance issues such as increased stiffness, loss of volatile components, and reduced flexibility.

The test is conducted by applying a thin film of bitumen onto standardized trays and placing them inside the Thin Film Oven, where the sample is exposed to controlled heating and airflow for a specific duration, typically at 163°C for 5 hours. During this process, volatile compounds evaporate, leading to weight loss and alterations in the binder’s properties. Once the heating cycle is completed, the sample is analyzed for weight loss, viscosity changes, softening point variations, and penetration alterations, all of which indicate how much the material has aged due to thermal exposure.

This method is widely used in asphalt mix design, quality control, and research to ensure that binders meet international standards such as ASTM D1754 and AASHTO T179. By conducting Loss on Heat/Thin Film Oven tests, engineers can determine the long-term durability, resistance to aging, and stability of binders before their use in road construction projects. The results of this test play a key role in ensuring that pavements remain flexible, durable, and resistant to cracking, ultimately extending the lifespan of road infrastructure and reducing maintenance costs.