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The aims of this work were to determine the color change and physical–mechanical properties of polystyrene glulam from three tropical wood species. Wood laminas were cut from logs harvested from a young plantation forest of manii (Maesopsis eminii), mangium (Acacia mangium), and rubber-wood (Hevea brasiliensis). The laminas were impregnated with monomer styrene that was polymerized using potassium peroxy-disulfate as a catalyst and heat. Three-layer glulam was constructed from the polystyrene laminas, using isocyanate glue and cold press. For comparison purposes, three-layer untreated glulam and solid wood samples were prepared. The results showed that the color change of polystyrene glulam was very small compared with untreated glulam. Polystyrene glulam had the highest density, while the density of untreated glulam did not differ from that of the solid wood. The moisture content of all products was matched to the environment, and fulfilled the Japanese standard. Compared with both types of glulams, solid wood had lower values for modulus of rupture (MOR), modulus of elasticity (MOE), and hardness, but higher shear strength. Meanwhile, polystyrene glulam had lower values for MOR and MOE, equal shear strength and wood failure, and higher hardness than the untreated glulam. All glulams had very little delamination in the hot water test. Only rubber-wood glulams fulfilled JAS 234-2003 for MOR, MOE, shear strength, and delamination. To obtain adequate physical–mechanical properties of glulams, medium-density wood is recommended for glulam manufacturing.

The objective of the study was to determine the effect of various layer compositions on the properties of 3-layer vertically glued laminated bamboo beam (LBB). Bamboo strips for LBB fabrication were prepared from mature culms (± 4 years old) of andong bamboo (Gigantochloa pseudoarundinacea (Steud.) Widjaja) collected from private gardens in West Java. The strips were pre-treated by soaking them in 7% boron solution for four hours. Three-layer LBBs were manufactured with six different layer compositions, including bamboo combination with wood planks of manii (Maesopsis eminii Engl.) or sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes) as the core layer. The LBB was manufactured using Water Based Polymer-Isocyanate (WBPI) adhesive. The glue spread and cold pressing time 2 applied were 250 g/m and one hour, respectively. Results showed that the average density, moisture content, thickness 3 swelling, and width expansion of LBB were 0.65 g/cm ; 11.1%; 2.09%; and 1.99%, respectively. No delamination occurred in all samples using WBPI adhesive, which indicates high bonding quality. The average bonding strength and 2 percentage bamboo failure (dry test) of LBB were 61.6 kg/cm and 90%, respectively. The physical and mechanical properties of LBB were significantly affected by the layer composition. The presence of wood laminates as the core layer of LBB and the cross wide orientation of the core layer decreased mechanical properties of LBB. On the contrary, the presence of cross-layer in LBB structure increased dimensional stability of the produced LBB.Three-layer thick laminated bamboo beam made of vertically glued andong bamboo strips with various constituted layer composition and all constitued layers laminated together in parallel grain direction had strength values comparable to those of class II of solid wood strength, eventhough the core layer was made of sengon or manii planks.