Ductal® UHPFRC façade panels for the EDF Training Centre in Saclay

The design of the building is organized in strata. “Everything is structured to offer a legible and intelligible campus to users who must integrate this environment very quickly and learn how to find their way around”, the architects explained. The composition of the façade alternates 3 Ductal® and glass layers endowing the building with a specific visual identity. From the ground floor to the second floor, pre-fabricated shells made from projected dark brown through-coloured Ductal® concrete, dress the structure of the building. Large sized, these shells offer an unbroken visual of the lower level yet which still seeks to optimise the material. A dual-component, brown coloured, 75% transparent surface coating reveals the material of this 15 mm thick UHPFRC grid. On the 3rd floor, a slightly reflective curtain wall houses the catering and relaxation spaces giving out onto the countryside. The top two storeys are given over to accommodation, the volumes of the 270 bedrooms are closed 2 by 2 by pre-fabricated projected Ductal® shells which encompass rolling shutters and exterior joinery elements. A grey, 25% transparent coating rounds off this mineral crown. The application of projected UHPFRC is the culmination of 15 years research work on the use of Ductal®. This work gave rise to an innovative pre-fabrication technique. Up to now, building façades made from Ductal® concrete were cast but this time they were projected into wooden or elastomer moulds. To do this, the formula of the cement matrix had to be adapted to the projection technique. This process, enabling ultra-thin shells to be made, highlights the ductility of UHPFRCs, “this resilience by UHPFRC to deform with a return to the initial state enabled very large thin monoblock elements to be made”, said Pascal Pinet.L’Entreprise en charge de la réalisation des panneaux est l’Entreprise Betsinor