Ultra High-Performance Fiber-Reinforced Cementitious Composites for Thin Double-Curved Façade Shells

Abstract

The inherent durability of UHPCs (thanks also to the use of non-metallic fibers) makes their adoption promising in the view of more efficient façade panels with respect to other traditional solutions (as for example steel, stone or GRC). For the case at hand, the study has been carried out from the material to the structural level, starting from the definition of the mix design on the basis of the target performance, followed by a preparatory mechanical characterization of the material and by a preliminary design of the panel in order to fulfil the principles of structural stability and crack control. Given the final application of white façade doubled-curved shells, the major concerns were represented by durability and aesthetics, this translating into the need for a very homogeneous surface and in a strict cracks control during the service life of the panel. The fulfilment of those objectives has been sought by adopting white raw materials (white cement, filler and white marble powder and aggregates) and by introducing polymer fibers (not altering the color of the mix and avoiding any corrosion stain during the service life of the panel). Fluid-dynamics numerical simulations have been performed to assess the feasibility of the casting phase (notwithstanding the very limited panel thickness of 30 mm) and structural analyses have been carried out for the panel in order to optimize the geometry. The study clearly proves the promising possibilities provided by UHPC in terms of geometrical tailorability, durability and aesthetic effect.