New Developments of Porous Concrete and First Experiences in Germany

Porous surfaces of cement concrete (OPB) or asphalt concrete (OPA) have a permanent transfer of rainwater and additionally noise reduction potential compared to the dense microstructure with exposed aggregates concrete. Pervious concrete test sections in the field of heavy-duty highways previously reported, however, do not have sufficient durability. Causes of damage have included grain outbreaks in porous concrete and a lack of bond between concrete and base layer. In addition, the grip was reduced by the traffic load. Porous concrete for noise-reducing pavements is composed only with chips grain-size 5/8 mm and a cavity of 15 to 20 Vol.-%. To ensure adequate freeze-thaw resistance a polymer dispersion is added to the cement-paste. In order to avoid the existing drawbacks newly special polymer dispersion has been developed which has sufficient durability, even at low temperatures and high dynamic loads. The focus of the test track in April 2013 in Mainz-Amoeneburg was on gaining experience about the material´s workability and processing technology using a modified asphalt paver. To improve the durability and increase the flexural strength a section with standard cement CEM III/A 42.5 N and a further with high-performance cement CEM II/B-S 52.5 R was carried out. The roadway also serves as a reference for the forthcoming German FGSV- standard "Guidelines on Permeable Traffic Areas". The choice of the layer structure was performed according to the guidelines described in this leaflet.