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Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa
Thesis (MSc)--Stellenbosch University, 2025.
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| Language: | English |
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613881878183936 |
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| access_status_str | Open Access |
| author | Marshall, Duan David |
| author2 | Wessels, Brand |
| author_browse | Marshall, Duan David Wessels, Brand |
| author_facet | Wessels, Brand Marshall, Duan David |
| author_sort | Marshall, Duan David |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/134695 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:11.727Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/134695 Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa Marshall, Duan David Wessels, Brand Balboni, Bruno Stellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science. Wood -- Bonding Eucalyptus Laminated wood -- Testing Wood -- Density Thesis (MSc)--Stellenbosch University, 2025. Marshall, D. D. 2025. Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/5348567f-c1d3-4abb-86a1-063c02ef430f ENGLISH ABSTRACT: In South Africa, Eucalyptus pulpwood logs are mainly used for producing chips intended for board and paper products. Due to the high amount of growth stresses, splitting, dimensional instability, and cell collapse during drying, Eucalyptus is not extensively used as a construction material. Some of these wood quality challenges can be ameliorated by gluing wood together into engineered wood products such as CLT. As such, determining suitable adhesion conditions for high quality CLT manufacturing becomes a priority, especially in an environment where different taxa are often processed together. The objectives of this study were: • To evaluate how adhesive type and wood density affect the bonding quality of cross laminated timber from three commercial Eucalyptus taxa (Eucalyptus grandis, Eucalyptus nitens, and Eucalyptus saligna X urophylla). • A secondary objective was to evaluate whether wood from two different Eucalyptus taxa can be mixed when bonding CLT products. The experimental design consisted of two factors namely taxa (Eucalyptus grandis, Eucalyptus nitens and Eucalyptus saligna x urophylla), and adhesives (PUR and MUF). The effect of wood density was evaluated afterwards, since groups were not created beforehand, it was not considered an experimental design factor. CLT panels consisting of different combinations of these factors were created whereafter shear and delamination tests according to the EN 16351 (2021) standard were conducted. Two smaller studies were also conducted namely delamination tests on mixed taxa CLT (Eucalyptus nitens and Eucalyptus saligna x urophylla), as well as an investigation into the influence of bond line thickness on shear strength. Adhesive type had no effect on bonding quality as measured by shear strength. However, adhesive type did have a significant effect on the bonding quality as measured by delamination. For both MUF and PUR, bonding quality was taxa dependent. Wood density had a significant positive relationship with shear strength, with non-parametric correlations supporting this. Non-parametric analysis revealed a weak but significant, positive correlation between density and delamination. Mixed taxa samples (E. nitens and E. saligna x urophylla) showed a great degree of delamination, failing delamination requirements as set out by the EN 16351 (2021) standard. This combination of taxa and adhesives does not seem suitable for CLT manufacturing. Bond line thickness had a negative effect on shear strength while the lack of statistical significance is attributed to the small number of samples, resulting in a potentially misleading p-value. Possible counteractive effects between PUR and MUF make it necessary for a new experimental design where the adhesives are analyzed separately. The adhesive performance is taxa dependent with PUR being more suitable for Eucalyptus saligna x urophylla while MUF performed better with Eucalyptus nitens. All combinations of taxa and adhesive passed delamination requirements as set out by EN 16351 (2021) except for E. grandis x MUF and E. nitens x PUR suggesting that theses combinations are unsuitable for CLT manufacturing. The remaining combinations of taxa and adhesives demonstrate bonding strength suitable for CLT manufacturing. AFRIKAANSE OPSOMMING: In Suid-Afrika word Eucalyptus-pulphout hoofsaaklik gebruik vir die vervaardiging van spaanders wat bestem is vir bord- en papierprodukte. As gevolg van die hoë groeispanning, spleting, dimensionele onstabiliteit, en sel-ineenstorting, word Eucalyptus nie algemeen as ‘n konstruksiemateriaal gebruik nie. Sommige van hierdie houtkwaliteitsprobleme kan verbeter word deur die vervaardiging van saamgestelde houtprodukte soos CLT. Daarom is die bepaling van geskikte lastoestande vir hoë gehalte CLT-vervaardiging 'n prioriteit, veral in 'n omgewing waar verskillende spesies dikwels saam verwerk word. Die doelwitte van hierdie studie was: • Om te evalueer hoe gomsoort en houtdigtheid die lasgehalte beïnvloed van CLT vervaardig uit drie kommersiële Eucalyptus-spesies (Eucalyptus grandis, Eucalyptus nitens, en Eucalyptus saligna x urophylla). • ’n Sekondêre doelwit was om te ondersoek of hout van twee verskillende Eucalyptus-spesies gemeng kan word om CLT-produkte te vervaardig. Die eksperimentele ontwerp het uit twee faktore bestaan, naamlik spesie (Eucalyptus grandis, Eucalyptus nitens en Eucalyptus saligna x urophylla), en gomsoort (PUR en MUF). Die effek van houtdigtheid is daarna geëvalueer, aangesien groepe nie vooraf vir digtheid geskep was nie; is dit nie as ’n eksperimentele ontwerpfaktor beskou nie. CLT-panele bestaande uit verskillende kombinasies van hierdie faktore is vervaardig, waarna skuif- en delaminerings-toetse uitgevoer is volgens die EN 16351 (2021)-standaard. Twee kleiner studies is ook uitgevoer, naamlik delaminerings-toetse op CLT vervaardig van gemengde spesies (Eucalyptus nitens en Eucalyptus saligna x urophylla), asook ’n ondersoek na die invloed van las-dikte op skuifsterkte. Gomsoort het geen effek op die lasgehalte, soos bepaal deur skuifsterkte, getoon nie. Die gomsoort het egter ’n beduidende invloed op die lasgehalte, soos bepaal deur delaminering, getoon. Vir beide MUF en PUR was die lasgehalte afhanklik van die spesie. Houtdigtheid het ’n beduidende positiewe verhouding met skuifsterkte getoon, en nie-parametriese korrelasies ondersteun hierdie bevinding. Nieparametriese analise het ’n swak maar beduidende positiewe korrelasie tussen digtheid en delaminering getoon. Gemengde spesie-monsters (E. nitens en E. saligna x urophylla) het ’n groot mate van delaminering getoon, en het nie aan die delamineringsvereistes soos uiteengesit deur die EN 16351 (2021) standaard voldoen nie. Hierdie kombinasie van spesie en gomsoorte is nie geskik vir CLTvervaardiging nie. Las-dikte het ’n negatiewe effek op skuifsterkte gehad; die gebrek aan statistiese betekenisvolheid word toegeskryf aan die klein aantal monsters, wat moontlik ’n misleidende p-waarde tot gevolg het. Moontlike teenwerkende effekte tussen PUR en MUF maak dit nodig vir ’n nuwe eksperimentele ontwerp waar die gomsoorte apart ontleed word. Die gomprestasie is spesie-afhanklik, met PUR wat meer geskik is vir Eucalyptus saligna x urophylla terwyl MUF beter presteer het met Eucalyptus nitens. Alle kombinasies van spesies en gomsoorte het aan delamineringsvereistes soos gestel deur EN 16351 (2021) voldoen, behalwe vir E. grandis x MUF en E. nitens x PUR, wat daarop dui dat hierdie kombinasies nie geskik is vir CLT-vervaardiging nie. Die oorblywende spesies- en gomkombinasies toon lassterkte wat geskik is vir CLT-vervaardiging. Masters 2025-12-24T06:18:26Z 2025-12-24T06:18:26Z 2025-12 Thesis https://scholar.sun.ac.za/handle/10019.1/134695 en Stellenbosch University vi, 71 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Wood -- Bonding Eucalyptus Laminated wood -- Testing Wood -- Density Marshall, Duan David Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa |
| title | Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa |
| title_full | Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa |
| title_fullStr | Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa |
| title_full_unstemmed | Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa |
| title_short | Investigation of the bonding quality of cross-laminated timber from three young Eucalyptus taxa |
| title_sort | investigation of the bonding quality of cross laminated timber from three young eucalyptus taxa |
| topic | Wood -- Bonding Eucalyptus Laminated wood -- Testing Wood -- Density |
| url | https://scholar.sun.ac.za/handle/10019.1/134695 |
| work_keys_str_mv | AT marshallduandavid investigationofthebondingqualityofcrosslaminatedtimberfromthreeyoungeucalyptustaxa |