Purpose
This research aimed to produce strong, reliable glue-laminated timber (GLT) from plantation-grown Eucalyptus nitens. This species is normally used for paper pulp and isn’t often chosen for high-value building applications.
Summary
This project investigated how to make glue-laminated timber (GLT) beams from plantation-grown E. nitens. Boards were graded and sorted using non-destructive acoustic tests and mechanical property measurements, then different ways to join and glue the boards were trialled. Key factors like press pressure, pressing time, glue amount, and surface treatments to improve bonding were tested. Three adhesives were trialled, and both finger-jointing and face-gluing methods were evaluated. Prototypes were tested for strength using bending and tension tests, as well as delamination checks. Results showed that E. nitens can be used as the main material for GLT, especially when high-quality boards are placed on the outside layers. The right combination of grading, jointing, and gluing produced beams that met structural standards, proving that plantation E. nitens can be used for reliable, engineered timber in construction.
Benefits to the Forest and Wood Products Industry
This research demonstrated several benefits for the timber industry:
- Using high pressing pressure made the glued Eucalyptus nitens wood much stronger, improving the quality of glue-laminated timber (GLT) beams.
- changing glue amount or pressing time had little effect, helping manufacturers focus on the most important factors for strong bonds.
- Vertical finger joints gave better strength in terms of rupture (MoR), while using a primer improved stiffness (MoE) in these joints.
The project also highlighted that current Australian standards (AS 1328.1) limit the market for hardwood GLT, so adopting the European standard (EN 14080) is recommended until a specific hardwood glulam standard is available, helping the industry access broader markets.
Acknowledgement
This work was supported by funding provided to Forest and Wood Products Australia (FWPA) to administer the National Institute for Forest Products Innovation program (NIFPI).
Funding for the program was provided by the Australian Government, the Tasmanian Government and Australian forest and wood products industry.
