Bitumen healing investigation using a specific fracture test
Résumé
In order to estimate the influence of bitumen on the fatigue behaviour of bituminous
mixes, a test was developed and allows to estimate fracture properties and healing capacity of
bitumen. A thin film of binder between two steel protuberances, simulating the pseudo contact of
two aggregates, was subjected to successive tension loads with a constant strain rate during the
test. Applying a rest period between every tension stage allows healing in the thin bitumen film.
Evolution of the crack size during the test was investigated using different methods. This paper
deals with the combination of the experimental evolution of the sample stiffness, modelling of
the considered test and ultrasonic measurement. The modelling method, shortly described here,
integrates both viscoelasticity and the sample geometry. A quantitative method using ultrasonic
measurement is also presented to study crack size evolution when the test is repeated several
times.