Feasibility of utilising waste tyre steel fibres to develop sustainable engineered cementitious composites: Engineering properties, impact resistance and environmental assessment

This study investigates the feasibility of developing sustainable engineered cementitious composite (ECC) with polyvinyl alcohol fibre (PVAF) and recycled tyre steel fibre (RTSF) to reduce the total cost of construction materials and ease the environmental pressure for disposing of waste tyres, putting an emphasis on the engineering properties, impact resistance and environmental assessment. Experimental results reveal that partially replacing PVAF with RTSF can reduce the loss in fluidity and promote flexural performance, while the fibre bridging stress of ECC can reach up to 4.41 MPa because of the enhanced fibre bridging effect. The dynamic compressive properties of ECC present a typical strain rate effect regardless of the fibre content, and the replacement of 0.25 vol% RTSF would cause a further 5.03%–25.55% increase in total dissipation energy within the strain rates of 58.2–124.5 s⁻¹, relative to ECC reinforced by 2.0 vol% PVAF. The synergetic effects of hybrid fibres on dynamic compressive properties of ECC can be explained by the bridging and pull-out effects of PVAF at lower strain rates, as well as the enhanced fibre-to-matrix bonding of hydrophilic RTSF at relatively higher strain rates. Upcycling of waste steel fibres in ECC holds promise as a cost-effective and eco-friendly solution for defence engineering constructions.