LOW-NOISE PAVEMENTS: THE SOLUTIONS OFFERED BY THE FRENCH ROADBUILDING INDUSTRY

摘要

In France, tyre-road noise measurements carried out on new or maintenance road construction sites constitutes a national database allowing a pavement raking in three main families (low noise pavements, intermediary and noisy pavements). From this classification, we conclude that two main factors have an important effect on a low noise pavement formulation. These are: the granularity and the void content which is connected to the acoustic absorption. For about twenty years, drainage asphalts have been the first low noise pavements developed in France. More recently, we took a new orientation and we began to study twin-lay porous asphalt concretes. In addition, since five years, French road companies have developed a new concept of low noise very and ultra thin layer bituminous concretes. These new pavements structures have interesting characteristics which fulfil the previous two requirements (granularity and the void content) together with satisfactory mechanical and skid resistance properties. Concerning their acoustical properties, we observe an average improvement around 3 to 4 dB(A) in terms of LAeq (6.00 / 22.00) with respect to the French reference 0/10 bituminous concrete pavement. Nevertheless, considering their present knowledge of the phenomena involved and of the measuring methods they practice, French companies wish that the acoustic performances level of those products remains a qualitative objective and do not become contractual in deals context.