Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber
Thesis (MSc)--Stellenbosch University, 2026.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Stellenbosch : Stellenbosch University
2026
|
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613758720835584 |
|---|---|
| access_status_str | Open Access |
| author | Van Schalkwyk, Johannes |
| author2 | Wessels, C. B. |
| author_browse | Van Schalkwyk, Johannes Wessels, C. B. |
| author_facet | Wessels, C. B. Van Schalkwyk, Johannes |
| author_sort | Van Schalkwyk, Johannes |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135650 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:41:14.564Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135650 Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber Van Schalkwyk, Johannes Wessels, C. B. Balboni, Bruno Stellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science. Thesis (MSc)--Stellenbosch University, 2026. Van Schalkwyk, J. 2026. Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/1214a95f-9bbf-4ab0-8a31-08caf34a9818 Cross-laminated timber (CLT) is an engineered wood panel that consists of at least three layers that are orthogonally oriented from each other and usually joined with structural adhesive. The high capital cost of hydraulic and pneumatic presses used for CLT layer bonding is a potential barrier to the widespread adoption of this product in South Africa. Eucalyptus grandis is readily available and has a fast growth rate, making it an attractive option for meeting timber supply demands in South Africa. In this research, the use of a lower-cost combined mechanical-adhesive joining method was investigated with the use of Eucalyptus grandis raw material. The objective of this study was to evaluate the mechanical performance and durability of CLT manufactured with nails to maintain the pressure required for structural adhesive joints, using young Eucalyptus grandis timber. The experimental layout of the study consisted of four tests that compared nail-joined CLT specimens with a control treatment. The tests included: a four-point bending test to evaluate modulus of rupture (MOR) and modulus of elasticity (MOE), a shear test on both fresh and degraded specimens, and a delamination tests on two specimen sizes. Finally microscopic analysis was done on the nail-joined CLT specimens to investigate factors influencing the bond line thickness. Nail-joined CLT specimens showed significantly lower bending strength than controls, with mean MOR values of 22.9 MPa versus 32.0 MPa of the control, underscoring the importance of clamping pressure for bond quality on mechanical performance. Despite this, nail-joined CLT specimens exhibited roughly 15% higher stiffness (MOE 7527.4 vs 6547.9 MPa), likely influenced by higher wood density and nail reinforcement. Delamination tests revealed poor bonding performance, as nail-joined CLT failed the EN 16351 criteria and displayed far greater delamination (63.2% vs 10.9%), resulting in reduced shear strength after degradation. Short-span bending tests showed higher shear strength of nail-joined CLT compared to a control (2.5 vs 2.15 MPa). This was likely due to the nails increasing resistance to rolling shear deformation and to the higher mean wood density of the nail-joined CLT. Microscopic analysis indicated that cut type, rather than nail proximity or bond line position, significantly affected bond line thickness in nail-joined CLT. Parallel cuts at laminate edges showed uneven adhesive distribution compared to more uniform cross-cuts from laminate centres. Nail-joined CLT showed higher mean bending stiffness and shear strength than control treatments but lower mean and minimum bending strength. The weaker adhesive bond lines in nail-joined CLT resulted in non-compliance with EN 16351 requirements for total and maximum delamination. However, the delamination requirements of EN 16351 were developed for adhesive joints only, whereas the nail-joined CLT tested here also benefits from the security of non-degrading nails. With further research, this product could be used in applications with less stringent structural requirements, such as single- or double-storey residential housing. Masters 2026-04-07T08:11:42Z 2026-04-07T08:11:42Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135650 en Stellenbosch University 69 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Van Schalkwyk, Johannes Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber |
| title | Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber |
| title_full | Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber |
| title_fullStr | Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber |
| title_full_unstemmed | Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber |
| title_short | Evaluating the performance of young Eucalyptus grandis nail-joined cross-laminated timber |
| title_sort | evaluating the performance of young eucalyptus grandis nail joined cross laminated timber |
| url | https://scholar.sun.ac.za/handle/10019.1/135650 |
| work_keys_str_mv | AT vanschalkwykjohannes evaluatingtheperformanceofyoungeucalyptusgrandisnailjoinedcrosslaminatedtimber |