Federal Highway Research Institute

Open porous concrete

Testing various installation technologies

The aim of the project is to develop an open porous concrete as a noise-reducing road surface.

The picture shows a roadsurface while fabrication


In addition to increasing durability and efficiency, concrete road construction tests in recent years have focused in particular on environmental aspects. A major factor here is noise control. Against this background, a noise-reducing concrete road surface has been developed and tested at BASt in cooperation with Gütegemeinschaft Verkehrsflächen aus Beton e.V. (GVB) and other partners from the industry.


The picture shows a concrete sample in a laboratory Laboratory investigation

OPC is concrete with a continuously porous structure which can be used for concreting the top layer (approx. 5 to 7 cm thick) on top of an already hardened first layer.

This form of road paving was selected because porous materials have a substantially shorter service life compared to those with a dense structure and therefore an explicit and where necessary multiple replacement of the top layer of concrete must be guaranteed. The following focus areas were addressed during development:

  • Specifying the relevant material parameters for the fresh and hardened concrete, as well as deriving and defining the requirements for practical use.
  • Preselecting suitable source materials for the multi-component system, iterative composition development and laboratory investigation into relevant material parameters typical for road construction.
  • Analysing engineering aspects for practical implementation, for example mixing and installation technique.
  • Bond between OPC and hydraulically bounded base layer (first layer).
  • Planning, producing and scientific support for a large-scale demonstrator at a large-scale test hall (model road) and for a test track on the national motorway network.

The findings from the above-mentioned project elements demonstrated that questions need to be answered, especially regarding installation methods and the durability of the concrete composition.


A further modified OPC composition was ultimately deployed in the installation test conducted on the duraBASt, which was installed with a road paver using different types of compaction screeds: conventional extendable screed and specially modified, rigid high compaction screed. In addition to the general findings regarding installation methods, this permits initial statements to be made on the potential installation quality.