eprintid: 10108122 rev_number: 21 eprint_status: archive userid: 608 dir: disk0/10/10/81/22 datestamp: 2020-08-24 15:07:35 lastmod: 2021-10-12 21:56:03 status_changed: 2021-01-21 19:37:47 type: article metadata_visibility: show creators_name: Wang, Y creators_name: Chan, CL creators_name: Leong, SH creators_name: Zhang, M title: Engineering properties of strain hardening geopolymer composites with hybrid polyvinyl alcohol and recycled steel fibres ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F44 keywords: Fibre reinforced concrete, Alkali-activated materials, Bendable concrete, Engineered geopolymer composites, Recycled fibre, Toughening mechanism note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions. abstract: Strain hardening geopolymer composite (SHGC) is an alkali-activated material reinforced with randomly dispersed short fibres, which exhibits high ductility and strain hardening and multiple cracking behaviour. This paper presents an experimental study on the effect of hybrid polyvinyl alcohol (PVA) and recycled tyre steel (RTS) fibres on engineering properties of fly ash-slag based SHGC cured at ambient temperature, including flowability, setting time, drying shrinkage, compressive strength and flexural behaviour in terms of stress–deflection response, first-crack strength and flexural strength, flexural toughness and toughening mechanisms. Four mix proportions of specimens with various volume fractions of hybrid PVA and RTS fibres including 1.5% PVA, 2% PVA, 1.75% PVA + 0.25% RTS and 1.5% PVA + 0.5% RTS were considered. The results indicated that the hybridisation of PVA fibre with RTS fibre led to a significant reduction in flowability, setting time and flexural strength of SHGC. However, the resistance to drying shrinkage and compressive strength of SHGC were greatly improved. Moreover, all specimens exhibited the expected deflection hardening behaviour with multiple stable microcracks formed over the tensile face of specimens under four-point bending. The addition of RTS fibre resulted in reduced crack widths in specimens where over 90% of cracks had a width of smaller than 60 μm. The mixture containing 2.0 vol% PVA fibre can be regarded as the optimal mixture for SHGC considering the strengths and deflection (or strain) hardening behaviour. date: 2020-11-20 date_type: published publisher: Elsevier official_url: https://doi.org/10.1016/j.conbuildmat.2020.120585 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1808657 doi: 10.1016/j.conbuildmat.2020.120585 lyricists_name: Zhang, Mingzhong lyricists_id: MZHAA72 actors_name: Zhang, Mingzhong actors_id: MZHAA72 actors_role: owner full_text_status: public publication: Construction and Building Materials volume: 261 article_number: 120585 issn: 0950-0618 citation: Wang, Y; Chan, CL; Leong, SH; Zhang, M; (2020) Engineering properties of strain hardening geopolymer composites with hybrid polyvinyl alcohol and recycled steel fibres. Construction and Building Materials , 261 , Article 120585. 10.1016/j.conbuildmat.2020.120585 <https://doi.org/10.1016/j.conbuildmat.2020.120585>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10108122/1/Full_Manuscript.pdf