Paper by RENS KEYMEULEN WIJNENDAELE from ISCR 11th 2010 Seville Spain
The technique of double-layered concrete or two-lift paving is applied either to obtain a high-quality top layer, to use lower quality materials in the lower lift, or for both reasons at the same time. In Europe this technique is commonly applied in Austria where a typical motorway is built with a 25 cm-thick jointed plain concrete pavement consisting of a 20 cm lower layer and a 5 cm upper layer. For the coarse aggregates of the first layer, recycled crushed concrete from former pavements replace the natural stones while the top layer is made of small, polishing-resistant stones with a maximum aggregate size of 8 mm. Driven by growing environmental awareness and a desire for innovation, the Flemish Road Authorities followed the Austrian example and planned a trial worksite on a 3 km section of the E34 motorway in Zwijndrecht near Antwerp. Following Belgian tradition, the existing JPCP was replaced with a CRCP. The paper will describe the pavement design and construction details, the concrete mix design and the evaluation of the road surface characteristics of the finished road. By adopting the CRCP long-life pavement concept, the use of reclaimed aggregates and the result of a quieter and smoother surface, different aspects of sustainable construction are combined, to good effect, in this technique.