Hybrid sandwich panels for building uses: focus on glass fibre reinforced polymer and mineral matrix interface.

Sandwich structures are being used increasingly in civil engineering because of their high strength, stiffness, and stiffness-to-density ratio. The studied sandwich structure was made of glass fibre reinforced polymer (GFRP) skins, and GFRP reinforced core. Two case studies are presented in this paper: a use as lightweight floor in building rehabilitation, and an application as façade panels. In both cases, the GFRP sandwich structure can be associated with a mineral matrix because of conventional construction methods and acoustic floor insulation in the first case, and because of architectural issues in the second. To design the hybrid sandwich panel and ensure monolithic mechanical behaviour, a finite element method (FEM) that predicts the interface failure was introduced. To implement the FE model by mechanical interface properties, pull-off and push-out tests were performed to assess the mode I and mode II stress limits. Four GFRP surface roughnesses and two configurations with chemical additions were tested. The three configurations that performed the best were tested by submitting the hybrid sandwich structure to three-point bending loading. The prediction of the interface failure by the FEM was assessed by comparison to the experimental data. Finally, full-scale panels were experimentally tested and designed for the named two uses cases thanks to the FE model