Development and optimization of a permanently low-noise top concrete layer with a near-surface, accessible macropore system, COPS (concrete with open-pored surface), the surface of which has the final texture after placement without additional processing steps

Duration: 2010 - 2014

Within the framework of research projects already carried out, it was established that tire-road noise is to be regarded as the dominant sound source in road traffic. The air pumping effect, the horn effect and the groove resonances play a dominant role in its generation. For concrete construction, attempts have so far been made to achieve a reduction in noise emissions by means of sufficient roughness depth. In Germany, this is achieved by the standard construction method of exposed aggregate concrete. In addition to the surface textures currently specified in ZTV Beton-StB 07 [N 1], however, it is also conceivable to produce a top concrete with a macropore system that is accessible to the sound pressure. In this case, very high sound absorption is achieved by the pores communicating with each other. In contrast to classic drainage concretes (usually single-grain concrete), a concrete with a specifically adjusted pore size is to be used for the quiet pavement to be developed here, by means of which the pore system can be optimized in terms of noise and durability properties. The aim of the investigations carried out as part of this research project was to develop and optimize a road pavement concrete which, thanks to its defined open-pored, near-surface structure and an adapted surface texture, leads to a reduction of more than 4 dB (A) in noise emissions as a result of flowing traffic compared with conventional, acoustically untreated road pavements. The primary objective was to achieve the acoustically effective surface texture without an additional work step immediately after production. At the same time, such a concrete should have the attributes of a durable road surface concrete. This concrete is referred to in the following as "low-noise concrete pavement with open porous surface".