Cast On-Site UHPFRC for the Rehabilitation of Existing Structures – Feedback Over 20 Years of Exposure to Chlorides

The first cast on-site application of Strain Hardening Ultra-High-Performance Fiber Reinforced Concrete (UHPFRC) in Switzerland took place for the rehabilitation and widening of the Bridge over the river “La Morge” near the town of Sion in the Swiss Alps in 2004 in the framework of the EU project SAMARIS. Over the last 20 years, this technology has been successfully applied in Switzerland for bridges and buildings under the impulse of MCS/EPFL and is now in practice with over 400 applications. An experimental campaign and a detailed visual survey were performed after 19.5 years of exposure to de-icing salts in spring 2024 to characterise chloride penetration in various parts of the bridge and validate the entire surface waterproofing function of the UHPFRC overlay. This is the first time that the performances of cast-on-site UHPFRC without thermal treatment have been investigated over such a long period.