Characteristics of Cross Laminated Timber Made from Jabon Wood based on Lamina Thickness and Angle Orientation

Abstract

Along with the technological developments, a new method of laminated timber has been found, called by cross laminated timber (CLT). CLT is an engineered product of wood composed of some lamina or layers bonded in an arrangement of layers crossing one another. The purpose of this research was to design a panel of CLT by modifying the combined patterns of different thickness and orientation angles of lamina in order to have the highest strength values and determine the characteristics of CLT panels as structural timber. The study results are expected to provide alternative benefits or uses of wood from the community forests as a product of CLT, give information to the people about the quality of CLT panel from the community forest and increase the chance of timber development from the community forests for structural wood products. The thickness of lamina applied in the manufacture of CLT panels were 1.0, 1.67, 2.0 and 3.0 cm with the width of 15 cm and the length of 120 cm. CLT panel was formed of three layers or lamina with the cross-sectional size of 5 cm x 15 cm x 120 cm based on the value of its MOE with three types of combination in lamina thickness, namely type A1 (1 cm, 3 cm, and 1 cm), type A2 (1 cm, 2 cm, and 1 cm), and type A3 (1.67 cm, 1.67 cm, and 1.67 cm). The middle layer was based on the orientation angles of lamina: 0°, 30°, 45°, 60°, and 90°. The adhesive used was water based polymer isocyanate (WBPI) with the glue spreading of 280 g/m2 for both surfaces. Testing was based on ASTM D 143 (2005) and JAS 234:2003 standard. The result showed that the combined thickness of lamina had a significant effect on the mechanical properties of MOE, MOR and compressive strength parallel to fibers on CLT panels. The lamina orientation angles had a significant effect on the physical properties of volume shrinkage and expansion on CLT panels. On the other hand, as for the mechanical properties, the angle orientation of lamina showed a significant effect on MOE, MOR, compressive strength parallel to fibers, and the bonding strength of CLT panels. The interaction between a combined thickness of lamina and angle orientation only significantly influenced the compressive strength parallel to fibers of CLT panels. Meanwhile, based on the scoring of CLT panel, the combined thickness of lamina type A3 and the angle orientation of 30o had the best properties. This is because the number of connections on the angle orientation of 30o Key words: Cross laminated timber, jabon wood, physical and mechanical properties, less than those of other angle orientations. The resulted analysis of the whole or intact timber (control) showed that in general CLT panels have better properties of volume shrinkage and expansion than the intact original timber.