Performance of glued laminated timber (glulam) made from Rubberwood with different lamina assembly patterns and adhesive spreads rates

Abstract

Glued laminated timber (glulam) is a great building material with strong mechanical properties that comprises laminated layers of wood (lamina) glued together with long-lasting structural adhesives. As the supply of large dimensional lumber for construction projects has been in shortage, glulam is the ideal material to replace the lumber because it can be made in various sizes and shapes, including unique arches using relatively small dimensional lumber. This research aims to investigate the effects of different lamina assembly patterns and adhesive spread rates on the physical and mechanical properties of rubberwood glulam. For this purpose, the lab scale of the 3-ply glulam was made from homogenous grades lamina of low-MOE, average-MOE, and high-MOE. In addition, the lab scale of the 3-ply glulam was also produced from mixed grades lamina of low-high-low-MOE and high-low-high-MOE. The glulam was tested to evaluate the physical and mechanical properties based on the Japanese Industrial Standards for glulam (JAS 234-2003). The results show that the lamina assembly patterns significantly affect the mechanical properties of the glulam. Accordingly, the glulam made from a high-MOE lamina at its compression and tension surfaces has the best mechanical properties compared to that made from the other assembly patterns. In addition, although the difference was insignificant, the results showed that adhesive spread rate has positively affected the mechanical properties of the glulam. The results showed that Rubberwood has the potential to be used as raw material for glulam production.