Rolling Thin Film Oven (RTFO)

ASPHALT ROLLING THIN FILM OVEN

ACCURATE BINDER HEAT AND AIR SIMULATION

The RTFO does a great job of simulating the short term aging that asphalt binder goes through during mixing, closely mirroring what happens out in the field.

When the Superpave PG binder specification was being developed, the goal was to find tests that could realistically simulate field performance. Hotmix asphalt binder undergoes considerable aging throughout the manufacturing and laying process, so being able to study this in a lab setting, using a test that’s both simple and repeatable, turns out to be incredibly valuable during the design process. That’s where the Rolling Thin Film Oven (RTFO) test comes in. It measures how heat and air affect a moving film of a semi-solid asphalt binder, and the results are worked out by comparing the binder’s properties before and after the test.

How repeatable the test is comes down largely to how accurately the oven can maintain its temperature, along with how consistent the system’s thermal rise time is. It was James Cox & Sons who originally invented the RTFO, and that early work eventually paved the way for the AASHTO, ASTM, and EN standards we rely on today for the Rolling Thin Film Oven test (RTFOT).