The Newlands West Drive, which serves as a mayor bus route and arterial to a large residential area, showed signs of distress in the form of cracking of the existing asphalt layers. The rehabilitation design called for an overlay to the existing road of 125mm thick foamed bitumen stabilised RAP and 40mm asphalt surfacing, alternatively the conventional rehabilitation method with the same structural capacity would have called for an overlay of a 100mm asphalt base layer followed by a 40mm asphalt surfacing layer.
Due to the increasing volume of stockpiled RAP at the municipal depots and the relative low stabilizing agent content required, the alternative using the in-plant recycling method resulted in a significant cost saving for the client. This project coincided with the 22nd PIARC World Road Congress. Thanks to the future orientated thinking of the Durban Municipality, an agreement was reached together with Milling Techniks and Wirtgen South Africa to showcase the in-plant recycling and foamed bitumen technology to the international road construction industry attending the congress.
The two halves of the road were completed in one day per section length of road, so that the entire road’s base layer width was newly constructed for the safety of night traffic. The foamed bitumen was trafficked immediately after final compaction and the asphalt layer constructed after approximately one week later.