Green-glued engineered products from fast growing Eucalyptus trees: a review
- PDF / 1,549,918 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 5 Downloads / 180 Views
ORIGINAL ARTICLE
Green‑glued engineered products from fast growing Eucalyptus trees: a review C. Brand Wessels1 · Michela Nocetti1,3 · Michele Brunetti3 · Phillip L. Crafford1 · Marco Pröller1 · Michael K. Dugmore1 · Calvin Pagel1,2 · Roman Lenner2 · Zahra Naghizadeh1 Received: 18 September 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The objectives of the work described in this paper were to present concept processing pathways for manufacturing high value, green-glued finger-jointed Eucalyptus engineered products and review existing research related to these engineered products. Additionally, critical knowledge gaps that need to be addressed in future research were identified. Research on four green-glued Eucalyptus products (green roof trusses, face-laminated beams, edge-laminated planks and panels, and CLT) and some of the processing steps involved, was reviewed. The research review showed that green finger-jointing seems to provide good quality bonds and is suitable for roof truss applications. The finger-jointed lumber has very different properties to existing softwood resources—which will make it more resource-efficient to define new stress grades for this wood resource. An engineered product where green Eucalyptus grandis was finger-jointed and then face-laminated before drying to equilibrium moisture content had much lower levels of checks, splits, and twist than products that were not face-laminated. Additionally, a higher material resistance factor can be used for this resource in comparison to the current value prescribed in the South African national timber design code. Material and processing variables for green edge lamination has been investigated and it has been found that high strength bonds are possible. Face bonding quality of dry Eucalyptus grandis for CLT has also been investigated and it was found that excellent face-bonding quality could be achieved when using a clamping pressure of 0.7 MPa and with no stress relief grooves present. Future research on this resource and product type should include studies on the process economics, process integration and durability treatment of green-glued, engineered Eucalyptus products.
1 Introduction The Eucalyptus genus is the most widely planted hardwood in the world due, mainly, to its adaptability and high growth rates. There are Eucalyptus plantations in more than 100 countries across six continents covering over 20 million ha (Myburg et al. 2014). Most Eucalyptus species, however, are rarely processed into sawn lumber due to processing problems associated with poor dimensional stability, splitting, brittle heart, excessive shrinkage, cell collapse, and checking after drying (Jacobs 1955; Malan 1984, 1993, 2003;
* C. Brand Wessels [email protected] 1
Department of Forest and Wood Science, Stellenbosch University, Stellenbosch 7600, South Africa
2
Department of Civil Engineering, Stellenbosch University, Stellenbosch 7600, South Africa
3
CNR-IBE, Institute for Bioecomony, Sesto Fiorentino, Italy
Vermaas and
Data Loading...
