Effect of layups on the mechanical properties of overlaid laminated bamboo lumber made of radial bamboo slices

Abstract

Radial bamboo strips are being widely used for structural applications due to the higher yield and high strength. However, there was a sharp taper at the top of bamboo which made nodal diaphragm removed incompletely during the process of stripping. The residual bump could bring about poor bonding strength between adjacent radial bamboo strips. In addition, the traditional radial bamboo strips should be weaved before the next step of processing, which caused a lot of material wastes and consumed a lot of labor and time. In order to address these problems, a novel lumber product made of laminated radial bamboo slices was developed by the proper arrangement of core layer and surface layer. The major and minor directions of a panel were defined as the parallel- and perpendicular-to-its arrangement ones in the core layer, respectively. It was found that (1) the layups with double-layer bamboo mats and radial bamboo slices could produce better mechanical properties. The effective modulus of elasticity in major and minor direction was about 7032.5 MPa and 5016.0 MPa, respectively. The effective modulus of rupture in major and minor direction was about 81.0 MPa and 43.6 MPa, respectively; (2) the density distribution tended to be uniform, with a density of about 0.7 g/cm3 that was lower than other similar bamboo-based materials (about 1.0 g/cm3); and (3) the failures occurred in bamboo slices rather than along the bond lines, suggesting good bond quality achieved in this study.