The presented research aims to develop the rubber fine powder in wearing course. It is interested particularly in the behaviour of two types of bitumen 40/50 modified by addition of two varieties of fine powders of rubber of different granularities. In addition to the objective of study and the evaluation of the influence of polymer added on the physical properties of the road bitumens, this work aims at following the influence of the granularity and proportioning in fine powders on the rheological performances of the bitumen by the intermediary of the tests of softening and Ring and of the tests of penetrability to the needle according to various contents. Except the environmental advantage, the tests carried out showed that the addition of fine powders, in a certain interval, has a significant influence on the mechanical properties and rheological of the analyzed bitumen and leads on a whole of interesting correlations.