The synergistic effects of fibres on mechanical properties of recycled aggregate concrete: A comprehensive review.

Recycled Aggregate Concrete (RAC) has attracted considerable attention for its potential to conserve natural resources and mitigate carbon emissions. Nevertheless, the widespread adoption of RAC in the construction industry faces challenges associated with its inherent performance deficiencies, including the formation of pores and microcracks in the recycled aggregate (RA) generated during the crushing process, as well as the presence of dual interfacial transition zones (ITZ) within the internal structure of RAC. The incorporation of fibres as reinforcement offers a promising solution to improve the performance of RAC. The paper begins with a comprehensive examination of various fibre properties and recycled aggregates. Then, summarizing the impact of fibres on RAC's performance. Special emphasis is placed on analyzing the influence of mixed fibres on the mechanical properties of RAC. The introduction of a blend of low-strength and high-strength fibres demonstrates the potential for further improving the mechanical properties of RAC beyond the benefits offered by individual fibres. This blending strategy also enhances the multiscale crack resistance of RAC, attributed to the collaborative effects of various fibres at different load stages. The reinforcing mechanism at the micro-scale of RAC is also discussed. Finally, the paper outlines perspectives for future research. [Display omitted] • A comprehensive review of hybrid fibre reinforced recycled aggregate concrete. • The effects of a single type of fibre on mechanical properties and microstructure. • Combining high-strength and low-strength fibres shows positive effects. • Blended fibres induce a dense C-S-H gel phase, enhancing cracking resistance. • The economic and environmental impacts are discussed. [ABSTRACT FROM AUTHOR]