Engineering properties and sustainability assessment of recycled fibre reinforced rubberised cementitious composite

To provide an eco-friendly disposal way of increasingly accumulated waste tyres and reduce the environmental impact caused by the production of industrial fibres, this study explores the feasibility of using recycled tyre materials as substitutes for natural fine aggregates and manufactured fibres in cementitious mortar. The effects of crumb rubber (CR) replacement ratio (5%-15% by volume of fine aggregates), recycled tyre steel (RTS) fibre content (0.5-1.5 vol%) and recycled tyre polymer (RTP) fibre content (0.5-1.0 vol%) on the engineering properties of fibre reinforced cementitious composite (FRRC) were experimentally investigated. Results indicate that the pre-treated CR using NaOH solution is feasible to combine with a high dosage of recycled fibres without considerably weakening the workability, bulk density, ultrasonic pulse velocity and compressive strength of FRRC. The incorporation of CR, RTS fibre and RTP fibre together can reduce the drying shrinkage by up to 41.6% and enhance the flexural strength by at most 174% as compared to the plain mortar. The production cost, embodied carbon and embodied energy of FRRC are decreased by 13.3%-68.2% when replacing the manufactured fibres with recycled tyre fibres. The optimal content of CR and RTS fibre and RTP fibre is 5%-10%, 1.0 vol% and 0.5 vol%, respectively, considering the engineering properties, cost and environmental impact. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the feasibility of using recycled tire materials in cementitious mortar, with results showing that replacing manufactured fibers with recycled tire fibers can reduce production costs, embodied carbon, and energy consumption while enhancing engineering properties. The optimal mixture includes 5%-10% CR, 1.0 vol% RTS fiber, and 0.5 vol% RTP fiber for improved performance, cost efficiency, and reduced environmental impact.