Properties of Rubberwood LVL reinforced with Acacia Veneers

Source: OAI


この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。 The properties of laminated veneer lumber (LVL) [15-ply, 3.6 mm veneer thickness] produced from Acacia mangium (Mangium) thinnings, Hevea brasiliensis (Rubberwood) and their combinations were investigated. Melamine urea formaldehyde (MUF) was used as the binder. In the species combination, Mangium veneers were incorporated in the tension and compression zones (i.e., top and bottom layers) of the LVL, with Rubberwood veneers in the core. The effects of two Rubberwood: Mangium combination ratios were studied, i.e., 3 : 2 and 1 : 2. Rubberwood LVL reinforced with Mangium exhibited a lower degree of bow compared to pure Rubberwood LVL. The LVLs were evaluated in accordance with the Japanese Agricultural Standard for Structural LVL (1993). All of the LVLs passed the cold water soak and boiling water delamination tests. Similar dry shear strength was registered by all of the LVLs, with shear retention of 58 to 63% after cyclic boiling. LVL with higher proportion of Mangium recorded higher shear strength retention. Modulus of elasticity (MOE) was found to increase with increasing Mangium plies in the faces. This is reflected by 2 and 12% MOE increment in LVL reinforced with 3 and 5 plies of Mangium, respectively. Reinforcement using 3 Mangium plies did not seem to improve the modulus of rupture (MOR), but 13% MOR increment was recorded by incorporating 5 plies of Mangium. Rubberwood and 3-ply Mangium reinforced LVL met the minimum requirements stipulated for 80E Special Grade, while the 5-ply Mangium reinforced LVL made the 100E Special Grade. Mangium LVL passed the 120E Special Grade.

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