Performance of crumb rubber concrete composite-deck slabs in 4-point-bending

A composite slab reinforced by profiled steel deck is a structural system where the longitudinal shear resistance between the steel deck and the concrete is the critical factor that governs the member capacity of the slabs under shear and/or flexural loads. Partially replacing concrete sand by crumbed rubber particles derived from used tyres to form crumb rubber concrete (CRC) can adversely affect the concrete mechanical characteristics; however, the plastic energy absorption and ductility of CRC have been shown to be improved. This paper presents an experimental study of large-scale composite slabs made of CRC or conventional concrete (CC) at similar compressive strength of 25 MPa that were tested under 4-point bending. Different shear spans and loading schemes were applied and tested in this study. The slabs were all 130 mm thick and had 3400 mm full span (800 mm shear span) for long slabs and 1800 mm full span (400 mm shear span) for short slabs. The overall performances, load carrying capacity, end-slippage, and interaction with steel of the tested CRC slabs were comparable or even better than those of the corresponding CC slabs, which indicated the viable substitution of CRC in composite slabs.