摘要：

Considering urgent ecological reasons linked to environment such as noise in urban environments and industrial waste recycling (worn tyres), the road engineer researches new processes or techniques taking into account these requirements: decreasing the noise level and enhancing the value of waste. Moreover, these techniques must reach, at least, the same performances as conventional materials used in road construction. As regards asphalt concrete designed for wearing courses, required surface characteristics must be kept and even increased and particularly skid resistance. The product presented here meets both requirements of waste recycling by incorporating worn tyres under the form of granular components and of noise reduction by a drop in the noise level of several dB (A). This asphalt concrete, named Colsoft, was designed by COLAS for wearing course. It belongs to the French category of very thin asphalt concrete. Its composition is presented, then several sites and finally the follow-up of the sites described. The advantages of the use of this asphalt concrete have been pointed out thanks to the follow-up of the sites by defining the areas of use and the manufacturing and laying rules to be complied with. If we take into account the obtained and measured performances as regards mechanical characteristics and skid resistance, the asphalt concrete is one of the best French road surface concretes. The sand patches, in function of its grading 0/6 or 0/10, are respectively ranged between 0.8 and 1.2 mm. Given the measurements of the longitudinal breaking force coefficient, this asphalt concrete ranges in the top of the French grading envelope, which means a good behaviour as regards skid resistance. Finally, noise measurements carried out according to the French standard S 31-119 and S 31-085, show a considerable drop in the noise level compared to the previous surface coating, which can reach 8 dB (A). This new generation of asphalt concrete meets the users' requirements as regards obtained comfort and safety and takes into account the environmental aspect on the one hand, by recycling worn tyres and on the other hand, by reducing the traffic noise in urban environments. For the covering abstract see ITRD E122374.

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