Despite significant amount of research on Recycled Tyre Steel Fibres (RTSF – extracted from end-of-life tyres) as reinforcement in concrete slab applications, the potential of RTSF is not fully understood mainly due to their variability in length (and aspect ratio). This paper investigates the effect of fibre length on the mechanical properties of Steel Fibre Reinforced Concrete (SFRC) using Recycled Tyre Cord Filaments (RTCF - extracted from unvulcanised rubber tyre belt off-cuts) which have very similar mechanical properties to RTSF. The flexural behaviour of SFRC prisms is evaluated using fixed lengths of RTCF (6, 9, 12, 15, 18, 21 and 24 mm) at a dosage of 30 kg/m3. Based on the flexural results, inverse Finite Element analysis (FEA) is used to determine the uniaxial tensile behaviour of the SFRC mixes. Mixes with fibres longer than 15 mm control macro-cracks well whilst residual flexural tensile strength fR increases almost linearly with fibre length, up to fibre lengths of 21 mm. Fibres with a length of 21 mm are the optimum for the mixes examined in this study in terms of post-cracking flexural behaviour and energy dissipation. The relative contribution of various fibre lengths (aspect ratios) in an RTSF mix is predicted well by using an equivalent energy approach. This work will help determine the efficiency of RTSF and speed up their adoption by industry.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)