Abstract

The over-exploitation of the forest has left the forest with small diameter logs. Apart from having small diameter, the trees are also characterized by juvenile wood with large proportion of sapwood, therefore, there is need for laminated board to meet the need of end users. This research assesses the effect of glue quantity and laminate dimension on strength properties of glue-laminated board of Tectona grandis (teak). T. grandis planks were converted to laminate sizes of 20mm x 20mm; 20mm x 10mm; 20mm x 5mm and 20mm x 2.5mm and laminated into boards with different glue quantities (10g, 20g and 30g). Strength properties such as the Impact strength, Modulus of Rupture, Compression strength, Shear strength both parallel and perpendicular to the grain were assessed and the results were subjected to Analysis of Variance. The mean values for Impact strength ranged from 18.55±2.16 to 32.83± 2.97 for the10g adhesive, while it ranged from 20.95± 1.37 to 32.70± 0.43fir 20g and 20.05± 0.09 to 32.90±3.22 for 30g quantity of adhesive. The for Modulus of Rupture varied between 63.27±10.07N/mm² and 101.91±3.47N/mm², for the 10g adhesive 68.72 ±4.82N/mm² and 101.92±3.38N/mm² for 20g adhesive, while for 30g adhesive, it ranged from 71.05±4.43 to 103.24±5.29. Compression Strength, ranged from 24.65±2.00N/mm² to 48.09±5.18N/mm² for the 10g and 25.25 ± 1.84 to 48.73 ± 5.49 for 20g, and 26.63 ± 2.72 to 48.73±5.49. For 30g Shear Strength in parallel direction to the grain and 9.57N/mm² to 24.29N/mm² for shear strength in perpendicular direction to the grain. It was therefore concluded that quantity of glue and laminate sizes have significant effects on the strength properties of the laminate board.

Keywords: Adhesive, Laminate, Compression strength, Modulus of Rupture, Shear strength