Comparison and improvement of strength of laminated and cross laminated beams obtained from scots pine and fir wood

In this study, the usage possibilities of solid and heat treated wood materials, cross laminated timber (CLT) and laminated wood material (Glulam) were investigated. After preliminary studies and literature review, for the production of three-layer CLT and Glulam Uludağ fir (Abies bornmülleriana Mattf.), Scotts pine (Pinus slyvestris Lipsky) and heat treated (Thermowood) pine tree species were decided to be used for this study. Polyurethane and melamine formaldehyde adhesives were preferred to be applied between the layers. Silane based surface conditioner was applied to the top layers of some test samples in addition to the adhesive. All the layers were made of solid wood material and one layer of heat-treated pine, and the other layers were consisted of solid wood for producing test samples. For prepared CLT and Glulam beam materials; Modulus of elasticity in bending, compressive and bending resistance properties were investigated. When the results of the experiments are examined, it is seen that PU glue gives better results than MF glue for both wood species in CLT and Glulam beams. When the silane surface conditioner primer and PU glue were used together, it was found that the strength increased. When the mechanical properties of the heat treated materials were used, it was observed that there was a decrease in load carrying capacity. The reason for this is explained by Boonstra (2008) in his study as, wood treated wood treated with solid wood material compared to the amount of water in the cell wall is less as a result of less hygroscopic and consequently less elasticity of wood material . In line with these results, it was concluded that wood panel systems with high strength and load bearing potential could be obtained when using silane primer together with PU glue during the production of CLT and Glulam building materials. It has been found that silane-based surface conditioning primer may be used in Glulam and CLT production.