Sustainable Road Building with Low-Noise Crcp on Belgian Motorways

motorway network in Belgium is now nearly complete, a large share of current road investment is allocated to the renovation of the oldest concrete pavement. Some asphalt roads are also being replaced with concrete, sometimes via the complete reconstruction of the road structure, sometimes by an inlay (of the slow lane). This paper describes some of the renovation carried out in Flanders (the north of Belgium) in 2001. Common to these works is the use of CRCP and exposed aggregate concrete as a surface finishing in order to provide a lownoise surface. In order to achieve this noise reduction, the maximum size of the exposed aggregate has for more than 10 years been limited to 20 mm and generally more than 20 % of these aggregates consist of the fraction 4/7. The first project involves an inlay of the right lane of a heavily trafficked main road (N31) where rutting has been a major problem. General recommendations for concrete inlays will be presented as well as the specific data of the case (traffic, geometric design, concrete specifications, concrete mix and test results). The second case is the reconstruction of a section of a 40-year-old motorway (A12) in jointed undowelled concrete to create a comfortable new road. Apart from the low-noise characteristics, other aspects of sustainable construction will be highlighted throughout this project (recycling, safety aspects, choice of cement type). While most people are now convinced that concrete can be a preferred solution in economical terms, when taking into account the whole-life cost including maintenance and if possible costs to the user, it has certainly become just as important to show that concrete roads are environmentally friendly and sustainable.