In co-operation with industrial partners, Nordic R&D firm VTT Technical Research Centre of Finland says it has developed permeable pavements, able to reduce the problems caused by storm and runoff water in urban areas.
The pavement solutions developed in the project are well suited for areas with low traffic volume, such as car parks, pavements, courtyards, fields and squares. The first Finnish pilots of the surfacing layers will take place in the cities of Espoo, Helsinki, Vantaa and Oulu in the spring of 2015.
The recently completed CLASS (CLimate Adaptive SurfaceS) project took two years to develop permeable pavement solutions for Nordic conditions with a materially different approach than traditional pavement layers and structures. Suitable materials include pervious concrete, porous asphalt and concrete and natural stone block paver systems where the material used in the joints or openings allows high water infiltration.
The permeable pavement consists of a surfacing layer and sub-surfacing materials with high porosity that can retain water. Other materials, products and structures can also be incorporated, such as drainage and water collection systems, geotextiles and geomembranes.
In the Nordic countries, it is important to consider the freeze-thaw durability of materials, as well as their behaviour in cold weather conditions. The project team focused on material performance in the subarctic climate, where infrastructures are subject to freezing and thawing ground frost as well as de-icing salt and sanding. Permeable pavements are already commonly used, in particular in Japan and the United States. More information about the CLASS project is available at http://www.vtt.fi/sites/class/.