Nine-ply plywood panels were produced from Eucalyptus grandis and Populus deltoids using urea-formaldehyde (UF) and phenol-formaldehyde (PF) adhesives. The physical and mechanical properties, such as moisture content, density, modulus of rupture (MOR) and modulus of elasticity (MOE) of the eucalyptus and poplar boards, were compared in this study. Samples were tested on both, along and across the grain. Higher values of MOR and MOE were observed for eucalyptus as compare to poplar. Density of ply board was observed as 500-560 kg.m-3 in plywood from poplar and 700-720 kg.m-3 in plywood from eucalyptus species. These differences were attributed to the variation in properties of veneer wood species. The effect of veneer wood species on some physical and mechanical properties of plywood was found statistically different.
To explore the feasibility of hem-fir for CLT products, this work addressed the exploratory and pilot plant studies of hem-fir cross-laminated timber (CLT) products through mechanical tests. The hem-fir lumber was procured and then stress-graded based on dynamic modulus of elasticity (MOE). The resulted 5-ply prototype CLT products were then tested non-destructively and 3-ply pilot plant hem-fir CLT was tested destructively. The results showed that bending performance of hem-fir CLT panel can be predicted. Considering cost-competitiveness and end applications of hem-fir CLT products, the panel structure can be optimized based on the stress-graded data of hem-fir lumber.
The aim of this study has been to investigate the suitability of Pannónia poplar (Populus × euramericana cv. Pannónia) timber for structural purposes. Static and dynamic modulus of elasticity (MOE) has been determined on samples of 4 different Hungarian plantation origins. The results of the dynamic test showed the same range as the static test, showing a good correlation of the two measurements. As result it can be stated that the domestic Hungarian Pannónia poplar species have in average 11000 N.mm-2 modulus of elasticity. This exceeds considerably the threshold limit value (7000 N.mm-2) necessary for structural applications according to Eurocode 5. Therefore Pannonia poplar is suitable for structural applications, and are a good alternative of the widely used coniferous species in construction sector.