The Superpave PG binder specification looked for tests which would closely simulate field performance. Hotmix asphalt binder experiences significant aging during the manufacturing and laying process. Investigating this phenomenon within a laboratory environment, with a repeatable and simple test is very useful within the design process.

The Rolling Thin Film Oven (RTFO) test is used to measure the effect of heat and air on a moving film of semi-solid asphalt binder. The results of this treatment are determined from measurements of the binder properties before and after the test. Repeatability of the test is directly related to the accuracy with which the oven temperature can be maintained and the reproducibility of the thermal rise time of the system. The invention of RTFO by James Cox & Sons led to the present day AASHTO, ASTM and EN standards for Rolling Thin Film Oven test (RTFOT).