Rehabilitation projects aim to enhance durability and to ensure structural safety. Ultra-High Per-formance Fibre Reinforced Concretes (UHPFRC) may fulfil these requirements when used as conservation materials. The structural response of composite UHPFRC-concrete elements under 4- point-bending was studied by means of experiments and an analytical model with the UHPFRC layer being under tension. Different depths of the UHPFRC layer were tested and rebars were placed in the UHPFRC layer in order to enhance the structural response. The re-sults demonstrate the outstanding mechanical properties of UHPFRC in terms of structural re-sponse in composite elements. The addition of rebars in the UHPFRC layer enhances significantly resistance and stiffness and delays crack formation. An original analytical model allows to predict the moment- curvature relationship of composite UHPFRC-concrete elements.