New concepts for low noise concrete road surfaces

Increasing road traffic requires road surfaces that are simultaneously durable and low noise. Durability could be best provided by concrete roads, but standard concrete road surfaces do not achieve noise reductions better than -2 dB, which is not sufficient to compensate the increase of noise levels due to increasing overall traffic volume.Nevertheless, theoretical investigations considering the mechanisms of tyre road noise generation show a much higher noise reduction potential for concrete roads. In German and international research projects several concepts of low noise concrete road surfaces have been investigated, including the optimization of standard road surfaces like exposed aggregate concrete or the postprocessing of concrete roads by grinding but also porous concrete. In addition, new surface types have been developed from a virtual design, taking into account the deeper understanding of tyre road noise generation: these concepts include specifically designed road surface textures, novel materials for road construction such as ultra high performance concrete or specially designed porous concrete. Some of these surfaces have been built on site to assess the achieved noise reduction capacity in practice.This paper resumes the projects' outcomes and the respective achievable noise reduction, durability and technical feasibility of the investigated concrete road surfaces.