The objective of this research was to evaluate the effect of bamboo species and resin content on the physical and mechanical properties of oriented strand boards (OSBs) prepared from steam-treated bamboo strands. The strands from three species of Indonesian bamboo, namely Andong (Gigantochloa verticillata), Betung (Dendrocalamus asper), and Ampel (Bambusa vulgaris), were steamed at 126 °C for 1 h at a pressure of 0.14 MPa. Three-layered OSBs with the core layer oriented perpendicularly to the face layers were prepared by bonding them together with 3 to 5% methylene diphenyldiisocyanate (MDI) resin based on ovendried strands and with the addition of 1% paraffin. The strand compositions for the face, core, and back layers were 25%, 50%, and 25%, respectively. The slenderness ratios and aspect ratios of the strands ranged from 71.02 to 76.60 and from 2.96 to 3.02, respectively. The physical and mechanical properties of the OSBs fabricated from Andong and Betung were better than those from Ampel, and the properties of all OSBs were improved by increasing their resin content. OSBs from Betung with 3 to 5% resin content and those from Andong and Ampel with 4 to 5% resin content showed strength retention of more than 50%, which means they can be used for exterior structural applications. Except for OSBs fabricated from Ampel with 3% resin content, the properties of all OSBs prepared in this study were higher than the minimum values required by the CSA O437.0 (grade O-1) standard (2011).

The objectives of this research were to evaluate bamboo-oriented strand board (BOSB) characteristics made from betung (Dendrocalamus asper), ampel (Bambusa vulgaris), and their mixtures at two different contents (3% and 5%) of methylene diphenyl di-isocyanate (MDI) adhesives. The strands were steam-treated at 126°C for 1 h under the pressure of 0.14 MPa. Three-layered BOSBs with a target density of 0.7 g/cm3 were made with the size of 30 cm x 30 cm x 0.9 cm and a shelling ratio of 1:2:1 (face:core:back layers). The physical and mechanical properties of BOSB were evaluated following JIS A 5908 (2003) standard, and the results were compared with the CSA 0437.0 Grade O-1 standard. The results show that BOSB from the mixtures of betung and ampel bamboo strands has higher dimensional stability as shown by the decrease in water absorption and thickness swelling and higher mechanical properties than single BOSB. All BOSBs with 5% resin content have higher dimensional stability, MOE, and MOR than BOSB with 3% resin content. The physical and mechanical properties of all BOSB manufactured met the CSA 0437.0 Grade O-1 standard. This study proved that BOSBs from the mixture of betung and ampel strands have the potential to be developed due to having better physical and mechanical qualities than a single BOSB. Keywords: ampel (Bambusa vulgaris), bamboo oriented strand board, betung (Dendrocalamus asper), resin content, strand mixtures