Engineering properties of sustainable engineered cementitious composites with recycled tyre polymer fibres

Abstract

To lower the material cost and environmental impact of polyvinyl alcohol (PVA) fibre reinforced engineered cementitious composite (ECC), recycled tyre polymer (RTP) fibres were adopted to partially replace PVA fibres in ECC in this study, with an overall aim to develop sustainable ECC with RTP fibres without significantly affecting the engineering properties. A series of tests were conducted to investigate the effect of RTP fibre content on the engineering properties of ECC, with special focus on tensile strain-hardening behaviour and dynamic compressive behaviour. Results indicate that the incorporation of RTP fibres can improve the drying shrinkage resistance of PVA fibre reinforced ECC by 5–13% at 28 d while no positive influences are found on the workability and quasi-static compressive properties. There exists clear strain-hardening behaviour for all studied ECC mixes even when 50% of PVA fibre is substituted with RTP fibre. Based on the results of the micromechanical investigation, all mixtures satisfy the criteria for achieving a robust strain-hardening behaviour. All ECC specimens are characterised by a pronounced strain rate effect under dynamic compression and ECC incorporating RTP fibres shows a stronger sensitivity as opposed to ECC with 2.0% PVA fibre. The material cost and energy consumption of ECC are reduced by about 11–45% and 5–18%, respectively, when RTP fibres are present. This study proves the feasibility of utilising RTP fibres in ECC to improve its sustainability and maintain acceptable static and dynamic mechanical properties while the incorporated fibre volume fraction should be limited to 0.5%.