ARCHES D14 - Recommendations for the use of UHPFRC in composite structural members – rehabilitation Log Čezsoški bridge

The increasing volume of European transport urgently requires an effective road and rail system in Central European and Eastern Countries (CEEC) with a major investment in building new and assessing and rehabilitating old structures. Following 5 successful applications of rehabilitation with Ultra High Performance Fibre Reinforced Concretes in Switzerland, since 2004, the same concept was applied to a bridge in Slovenia in July 2009 with new UHPFRC mixes from local products. An innovative concept of cement replacement by high dosages of limestone filler, developed at EPFL, helped break the workability barrier and produce a Slovenian UHPFRC with local cement (SALONIT), and superplasticiser (TKK), The material has excellent rheological properties and was tailored to be applied on slopes up to 5 %, without sacrificing the protective function and mechanical properties. The full section of the deck and footpaths of the 65 m span Log Čezsoški bridge over Soča river in Slovenia was cast in one step, over two days for the full length. An original combination of UHPFRC with Controlled Permeability Formwork (CPF) membrane (ZEMDRAIN®) developed at ZAG helped produce finished footpath surfaces ready to walk barefoot which was one of the challenges set by the owner. The specially tailored thixotropic mix held the 5 % slope without difficulties. The newly designed ECO-UHPFRC recipes have a dramatically reduced cement content which makes them more economical and particularly attractive from an environmental point of view. Over the whole life cycle, rehabilitations with ECO-UHPFRC have a much lower impact than traditional methods. This successful example of transfer of technology opens up very promising perspectives for the dissemination of this new concept of rehabilitation of civil infrastructures not only in New Member States (which was the goal of the project ARCHES) but also in virtually any country.