Flexural response of composite fibre cement sheeting-cementitious polystyrene sandwich panels

Sandwich panels have been acknowledged as possibly the most efficient structural systems in housing and multi-storey construction, due to the fact that they can be of very low weight and still have relatively high stiffness in bending. Depending on the materials and methods employed, a great variety of shapes and sizes may be attained, each with different functionalities. In order for these desirable features to be realised and maximised it is required that the two outer facesheets and the inner core be adequately bonded together to ensure composite action. The current study examines the flexural response of 3m long sandwich panels, whose composition is an expanded polystyrene-cement core, which is inorganically bonded to cellulose-fibre facings, in four-point bending. The quarter point loading position was chosen to maximise the region of constant moment between the load positions, and therefore simulate the uniform wind pressure that would be expected to be imposed on the panels in service. Strain gauges were attached to the top and bottom facings and an LVDT was used to capture the vertical displacements at the panel centre. The panels exhibited a brittle failure mode and, while it had been suspected that this failure mechanism would occur at mid-span, the panels broke into at least three pieces. No separation of the facings and core was observed.