Physico-mechanical properties of arc-laminated giant bamboo using thermally modified segments

The lamination of thermally modified giant bamboo [Dendrocalamus asper (Schult.) Backer] arc segments was investigated. Two thermal modification treatments were used, viz., steam and hot oil immersion. Lamination of arc-shaped bamboo segments was performed with polyurethane resin and the assembly was consolidated using an arc-shaped press mold. Results showed that laminates had reduced hygroscopicity and improved dimensional stability as indicated by a decrease in thickness swelling and water absorption compared to the control. Tests on mechanical properties indicated that steam or hot oil treatment had little or no effect on the laminates' compression, tensile shear strength and modulus of elasticity. Modulus of rupture, however, was reduced significantly by the thermal modification conditions used. Loading orientation (i.e., radial, and tangential) influenced the results of the properties on mechanical tests. In general, thermally modified arc bamboo segments can be bonded together, forming laminates with improved dimensional stability with little or no effect on mechanical strength properties except modulus of rupture. The laminates can be further processed to produce bamboo lumber with potential applications as a durable and sustainable building material.