Re-using Steel Wire from Tyres for Fibre Reinforced Concrete

Steel fibres used to reinforce concrete are normally manufactured from new high tensile steel wire. However, steel of a much higher quality is used in the manufacture of car and truck tyres and a significant volume of this material is recovered each year when end-of-life tyres are recycled. Tyre wire is often heavily contaminated with rubber and is usually either landfilled or, if sufficiently clean, sent to the steel mills for re-melting. Processes have now been developed to further clean and screen the recovered steel to enable it to be used as reinforcement in steel fibre reinforced concrete (SFRC). Whilst tyre steel tends to be of smaller diameter and length than the steel fibres traditionally used in SFRC, research has identified the range of fibre geometries that are effective. Research has also demonstrated that there are benefits to be had from using hybrid blends of standard manufactured fibres and re-used tyre fibres, with the different fibre types and geometries each contributing in different ways to the overall performance of the composite material. In conducting this research problems have been encountered with the manufacture of specimens for the internationally recognised prism test which disadvantage fibres of this type and recommendations are made that address this issue. Tyre steel offers a sustainable option for reinforcing concrete and this paper will demonstrate some significant structural, environmental and economic benefits of using this newly available material.