Behaviour of recycled tyre polymer fibre reinforced concrete under dynamic splitting tension

Recycled tyre polymer (RTP) fibre has recently been gaining ever-increasing attention from the scientific community as a promising substitute to synthetic fibres for cementitious composites to improve sustainability. This paper, for the first time, investigates the behaviour of RTP fibre reinforced concrete (FRC) under dynamic splitting tension, focusing on the effects of fibre content (0.1, 0.2, 0.4 and 0.8 vol%) and strain rate (0.88–3.54 s−1) and the feasibility of replacing polypropylene (PP) fibre with RTP fibre for FRC. Results indicate that the inclusion of RTP fibres is favourable in enhancing the splitting tensile properties of concrete under various strain rates (10−1 to 101 s−1), where the dynamic splitting tensile strength and dissipated energy of concrete mixture containing 0.2 vol% RTP fibre are improved by 5.5%–14.2% and 24.9%–36.7% respectively compared to the plain mixture as a result of fibre bridging effect. Fibre pull-out process considerably contributes to the enhancement of energy dissipation capacity. The splitting tensile properties of all mixtures are sensitive to strain rate, where the developed empirical equations well describing the relationship between dynamic increase factor (DIF) and strain rate provide insight into this rate sensitivity. A comparison between RTP-FRC and PP-FRC confirms that RTP fibre can be used as a sustainable and cost-effective alternative to PP fibre for cementitious materials considering engineering properties and potential economic benefit of the composites.