Effect of heartwood and sapwood veneer on specific strength/modulus of light weight laminated veneer lumber

In order to develop a new light weight laminated veneer lumber (LWLVL), effect of configuration of heartwood veneer to sapwood veneer in laminated veneer lumber (LVL) on specific strength/modulus of poplar LVL was studied. The four-structure LVLs were made with different configuration of heartwood and sapwood veneer. The bonding strength was tested and bonding interface was characterised. The main physical and mechanical properties of the LVLs were tested, as well as specific strength/modulus of the LVLs was evaluated to find LWLVL. The combination of sapwood veneer and heartwood veneer had different bonding interface morphology with different bondline thickness leading to bonding strength differences. The LVL with ratio of 3/2 of heartwood veneer to sapwood veneer with thin shell structure had the best comprehensive performance by radar chart analysis considering six physical and mechanical properties. The LVL with best specific tensile strength was named LWLVL, whose specific tensile strength is close to that of steel. It is supposed that the effective configuration of heartwood and sapwood veneer was an effective approach to enhance veneer utilisation to realise the light weight of LVL.