Wang, Yi;
(2022)
Engineering Properties of Hybrid Fibre Reinforced Strain Hardening Geopolymer Composites.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Strain-hardening geopolymer composites (SHGC) is an alkali-activated material reinforced with randomly dispersed short fibres, which exhibits high ductility and strainhardening behaviour with excellent crack control. Made from industrial by-products including fly ash (FA) and ground granulated blast-furnace slag (GGBS), SHGC is considered a promising and green alternative to its cement-based counterpart because of low carbon emissions, reduced energy consumption and superior mechanical properties. The incorporation of recycled tyre steel (RTS) fibre can further enhance the greenness of SHGC. Although the fresh and hardened properties of SHGC produced by various precursors have been increasingly investigated in recent years, a systematic study of strain-hardening behaviour and engineering properties of FA-GGBS based SHGC reinforced with hybrid polyvinyl alcohol (PVA) and RTS fibres and cured at ambient temperature is still lacking. This thesis aims to develop a hybrid PVA-RTS fibre reinforced sustainable SHGC with desired engineering properties based on micromechanics and fracture mechanics theory and investigate the effects of sand and fibres on the engineering properties of SHGC. Firstly, a series of tests were conducted to explore the effect of sand and obtain the optimum sand content for SHGC with acceptable engineering properties. Then, the micromechanical analysis was undertaken to verify the strength- and energy-based pseudo strain-hardening criteria of SHGC. Afterwards, the effects of PVA fibre and hybrid PVA-RTS fibres on engineering properties of SHGC were studied in terms of flowability, drying shrinkage, static and dynamical mechanical properties, strain-hardening and multiple cracking behaviours, and failure mechanisms. Microstructural characterisation was employed to gain insight into the toughening mechanisms of hybrid fibre reinforced SHGC, including fibre bridging effect, fibre fracture, and fibre pull-out. This thesis provides a comprehensive understanding of the strain-hardening behaviour and engineering properties of FA-GGBS based SHGC reinforced with hybrid PVA-RTS fibre and cured at ambient temperature for civil infrastructure applications.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Engineering Properties of Hybrid Fibre Reinforced Strain Hardening Geopolymer Composites |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Civil, Environ and Geomatic Eng UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10147501 |
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