Combining the most recent technologies in concrete, Ultra-High-Performance Fibre-Reinforced Concrete (UHPFRC) arises as a promising material for the near future. UHPFRC have shown how flexible concrete can be to adapt to the ever-changing social and environmental demands. With its high flexibility composition and its mechanical properties, UHPFRC is full of both unexplored and unexploited possibilities. Engineers should take responsibility for this task. However, it is fair to acknowledge that this is not an easy task and it requires the development of reliable and widely accepted design standards provided by the scientific community.

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For an attenuated surface wave (wave number K=K′+jK″), the resonant space-frequency S(x,ω) representation of a cylindrical shell is performed versus the angular position x. In this space, the MIIR properties are demonstrated. The resonant wave number-frequency representation Ksi(k,ω) is then obtained by spatial Fourier transform of S(x,ω). This two-dimensional second space clearly separates clockwise and anticlockwise propagating waves. The first ones are observed in the positive k values of Ksi, and the second ones in the negative k values of Ksi. The modulus of Ksi is maximum each time that the resonant condition is encountered [ω so that K′(ω) is integer]. As new results, the k cut of Ksi reveals the Sommerfeld Watson aspect of the problem and SWAM identify the complex K. On an ω cut of Ksi, SWAM identify the RST aspect of the target (and a little more): complex frequency resonances Ω=Ω′+jΩ″ for real modes n. SWAM is performed on experimental datas and on numerical form functions. The agreement with theoretical results obtained by RST is very good.

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