Experimental study on two-way prototype GFRG-RC floor slab systems

Glass Fibre Reinforced Gypsum (GFRG) prefabricated hollow panels, with the cavities filled with reinforced concrete (RC), are being used as load-bearing walls in Australia, India and other Asian countries. The same GFRG panels can be placed horizontally for use as floor or roof slabs. Studies on one-way GFRG-RC slabs reported in the literature (Paul et al., 2023), signify the contribution of GFRG to flexural strength and stiffness, which can be leveraged in structural design. The behaviour of two-way GFRG-RC composite slabs, simply supported on all four edges, differs significantly from that of one-way slabs and has not been studied in the literature. Thus, the main focus of the present study is to investigate the behaviour of GFRG-RC slabs under various loading types and with different aspect ratios. Experimental studies reveal that two-way slabs perform well under line and point loads, albeit with a lower load-carrying capacity compared to uniformly distributed loads. Furthermore, in comparison with one-way RC ribbed slabs, the strength enhancement in GFRG-RC slabs supported on all four edges can be safely increased from 10 percent (for aspect ratios >= 2) to 30 percent (for aspect ratio = 1). Additionally, a stiffness enhancement of at least 20 percent can be safely assumed for two-way action. This is corroborated by a water load test conducted on a section of the terrace slab of a two-storeyed GFRG building. Moreover, deflections and crack widths at the soffit of GFRG-RC slabs are found to be sufficiently low to warrant a serviceability check.