Cast-on site UHPFRC for improvement of existing structures - achievements over the last 10 years in practice and research

The first cast-on site application of UHPFRC in Switzerland took place for the rehabilitation and widening of the bridge over river La Morge in 2004. Since then, over the last 10 years, this technology spread successfully in Switzerland for bridges and buildings under the impulse of MCS/EPFL and is now current practice. Tests performed on the bridge over La Morge in 2014 showed that chloride penetration is extremely limited as expected and that the UHPFRC behaves fully according to the expectations. This is indeed the first time that the performance of cast-on site UHPFRC without thermal treatment is validated over such a long period of time. This paper highlights recent achievements of cast-on site applications of UHPFRC in Switzerland and abroad (Slovenia and France), with various types of UHPFRC including green mixes with limited clinker content. Associated research progresses over related fields are put into perspective with the practical applications. Results of chloride penetration over 10 years in a UHPFRC overlay are discussed in comparison with the performance of concretes used on bridge decks.