High-strength steel-fibre-reinforced concrete: potential use for ground slabs applications

Laboratory and analytical investigations were conducted to study the effect of steel fibres and concrete matrix strength on the behaviour of ground slabs. Three full-scale (3 m x 3 m x 0.1 m) slabs were precast, placed on a rubber mat, resting on a concrete floor, and centrally loaded either to failure or to the maximum loading-jack capacity. The tested load-carrying capacity of each slab was compared to theoretically estimated values using the Meyerhof model. Test results indicated that the addition of 60 kg/m(3) (0.76% by volume) of hooked-end steel fibres to concrete significantly increases the load-carrying and displacement capacities, changes the mode of failure from brittle to ductile, reduces cracking on bottom and top surfaces of the slab and allows a significant reduction in slab thickness. Increasing the concrete matrix strength of steel-fibre-reinforced concrete slab from 45 to 85 MPa had a marginal effect on the load-carrying capacity of the slab at points on the displacement response beyond the first crack point. Furthermore, the Meyerhof model was found to underestimate the load-carrying capacity of the tested ground slabs.