Swedish Experience with and Recommendations for Thin Concrete Overlays on Old Concrete Roads

This paper describes the Swedish experience with thin concrete overlays on old rutted concrete roads. In Sweden, the use of studded tyres leads to wedi and rutting on highways with intensive traffic. In the late seventies, some concrete roads were built in the South of Sweden. A thin concrete overlay on a part of this highway was tested. A milling machine was used to remove 35 mm of concrete. The milled surface was cleaned with a high pressure (800-900 bar) water jet "milling" machine. The overlay was cast with a steel fibre reinforced concrete. No bonding agent was used. Tests and measurements have been carried out on the suiface iuughness, bond, crecp, shrinkage, and thin section analysis. The average bond stress exceeded 2 MPa. Based on these investigations and the experience gained from the renovation of old concrete bridge decks, we have put foreward recommendations for thin concrete overlays.