| 1. |
- Kuqo, Aldi, et al.
(författare)
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Enhancement of physico-mechanical properties of geopolymer particleboards through the use of seagrass fibers
- 2023
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Ingår i: Construction and Building Materials. - : Elsevier. - 0950-0618 .- 1879-0526. ; 374
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Tidskriftsartikel (refereegranskat)abstract
- Two types of geopolymer-bonded boards were produced using initial wetting of lignocellulosic aggregates followed by dry mixing and hot-pressing. Boards were prepared by incorporating large fractions of lignocellulosic material (up to 50 wt%). Geopolymer particleboards (GP) were produced using wood particles whereas geopolymer sandwich boards (GSB) were produced from wood particles and seagrass fibers, with the latter allocated in the outer layers. Inclusion of seagrass fibers was found to enhance bending strength and toughness of GSB by up to 20 and 40 % respectively. The bending strength tended to increase with the addition of lignocellulosic aggregates, reaching up to 8.9 N mm−2. Fire resistance of GSB was slightly higher compared to GP. Further investigations such as FT-IR, XRD analysis and visual examination by digital microscopy showed an adequate degree of geopolymerization and mixing of the precursor and alkaline activator, indicating the high effectiveness of the mixing technique.
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| 2. |
- Olayiwola, H. O., et al.
(författare)
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Characterization of unary precursor-based geopolymer bonded composite developed from ground granulated blast slag and lignocellulosic material residues
- 2022
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Ingår i: European Journal of Wood and Wood Products. - : Springer Nature. - 0018-3768 .- 1436-736X. ; 80:2, s. 377-393
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Tidskriftsartikel (refereegranskat)abstract
- The excellent properties of geopolymer composites and their ability to be synthesized from various industrial waste streams make them promising green binders in wood-based composite manufacturing. The study characterized 100% slag unary precursor-based geopolymers reinforced with lignocellulosic material residue. The residue included sugarcane bagasse (SCB), Port Jackson (Acacia saligna) and Black wattle (Acacia mearnsii). The production process was established based on a mixed factorial design using Statistica 13.3. The factors considered included a curing pattern at 2 levels, sodium hydroxide concentration at 3 levels and lignocellulose material at 3 levels. Other parameters, such as precursor-activator ratio and sodium hydroxide-silicate ratio were constant. Statistical analysis revealed that curing temperature and sodium hydroxide concentration had a significant effect on the board properties and the addition of lignocellulose material improved the flexural strength. Curing at 40 degrees C influenced the reaction kinetics, enhanced microstructural properties, and produced a dense geopolymeric matrix which resulted in improved physical and mechanical properties. However, increasing the sodium hydroxide concentration beyond 6 M caused efflorescence and deteriorated the mechanical property of A. mearnsii and bagasse boards. Partial degradation of the fibres was confirmed by Fourier transform infrared spectroscopy and thermogravimetric analysis, but the degraded products did not inhibit geopolymer setting. Scanning electron microscopy indicated a uniform board structure surrounded with micro crystals of calcium silicate hydrate (C-S-H). A. saligna boards produced with 6 M NaOH and cured at 40 degrees C met the technical specification of cement-bonded particleboards for outdoor applications according to the British standard EN 634-2.
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