Fraass

In the Fraass breaking test, a thin layer of binder is poured onto a thin steel plate, The plate is positioned in a clamp. The clamp is squeezed resulting in the plate being bent, and then released sequentially. The whole set up is placed in a "cold chamber". The sample is cooled down and when a crack is detected in the bitumen layer, the Fraass Breaking Temperature has been established.

For polymer-modified bitumen, the breaking of the layer occurs in a different way to unmodified bitumen, and also the forces are different. The results are therefore not comparable. However, in both cases an indication is given at what temperature the product becomes brittle (in the case of unmodified bitumen) or stiff (for modified bitumen).

The Fraass temperature gives some indication but does not allow comparison on the absolute performance of binders.