MECHANICAL QUALIFICATION OF GREEN GLUED LAMINATED TIMBERS FROM THE CONGO BASIN TOWARDS PRESERVATION OF FOREST SPECIES DIVERSITY

Abstract

This study investigates the bending performances of full-size and green glued laminated timber (glulam) beams, manufactured under a tropical climate. Two types of beams were prepared: mono-species and mixedspecies glulam. The mono-species glulam with uniform layup were manufactured using abura (Mitragyna ciliata) and dabema (Piptadeniastrum africanum). The mixed-species glulam with balanced layup were manufactured by associating difou (Morus mesozygia) and abura, and tali (Erythrophleum ivorense) and dabema. These species were selected in the framework of a sustainable development of the glulam industry in Congo Basin, and clustering of their technological properties. A one component polyurethane adhesive was used, and the beams were dried artificially using vacuum. Pure bending tests were performed and the results showed an optimal bondlines thickness that ranged from 0.1 to 0.3 mm. Failure occurred in the solid woods indicating a satisfatory bonding quality of the glulam products. The strength properties of the glulam and solid woods presented compatible trends. Findings of this study showed that it is possible to develop high mechanical performance glulam products while improving the valorisation of lesser-known species, thus preserving the forest diversity in the Congo Basin.