The Structural Properties of Optimised Exposed Aggregate Concrete in the Netherlands

Indicative research on three new types of concrete roads by the Dutch Association of the Netherlands Cement Industry (VNC) in 1993 had shown that a concrete surface of exposed aggregates could be further optimised with respect to traffic noise reduction. In 1996, the Dutch Information and Technology Centre for Transport and Infrastructure (CROW) initiated extensive research to update the knowledge about the acoustical and the structural characteristics of concrete road surfaces. This research was conducted by performing the necessary noise tests as well as friction measurements and analyses. The optimisation of this so-called Exposed Aggregate Concrete (EAC) concerned the acoustical properties under the limiting conditions of skid resistance. Starting point was a fine gap-graded concrete mixture, in a thin surface layer. Various other countries have had good results with this kind of surface have. In the Netherlands, several test section were constructed with fine (4/7) and coarse (10/14) EAC. How construction was experienced and what structural properties have been obtained is described in this paper.