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Highlights • The density of overlaid laminated bamboo lumber improves with proper layup. • The density has a different impact on effective modulus of rupture between two panel directions. • Failure steps through the bamboo nodes and bamboo curtain joints. Abstract The overlaid laminated bamboo lumber (OLBL) was developed for structural applications with an aim to substitute commonly-used building materials such as steel and concrete. The OLBL was, via a hot press, fabricated by cross-laminating bamboo layers, bamboo mats and phenolic impregnated adhesive papers. Since the weight of OLBL was governed by the high density bamboo layer, the panels made of OLBL had a relatively high density value of about 850 kg/m3. In this study, a lightweight panel was developed by a proper arrangement of radial bamboo curtain. The major and minor directions of a panel were the parallel- and perpendicular-to-its length direction, respectively. It was found that 1) the density of an OLBL panel could be reduced by about 20%; 2) the failure occurred in the bamboo node(s); 3) there was a significant difference in effective modulus of elasticity and effective modulus of rupture between two panel directions; and 4) there was a good relationship between the density and strength in the minor direction. [ABSTRACT FROM AUTHOR]

• The volume utilization rate of bamboo residues is more than 85%. • The O 2 plasma modification time is 6min, the wet bonding strength is increased by 75.69%. • The staggered arrangement of bamboo pieces in LBL can reduce the influence of anisotropy. • After O 2 plasma modification, the wettability of bamboo was improved obviously. To improve the reuse rate of bamboo materials, laminated bamboo lumber (LBL) with high bond strength has been developed for structural use using bamboo residues (BRs). The laminated structure design is an important factor affecting LBL performance, and thus, it is essential to study various LBL blank structures. The major direction is parallel to the panel length, and the minor direction is perpendicular to the panel length. In this study, BRs were cut into A and B units along the major and minor directions, respectively. The LBL with good performance was selected by different forming methods and modified by O 2 plasma. It was found that 1) the volume utilization rate of BRs in LBL is above 85%; 2) the wet bonding strength of LBL products is increased by 58.58% compared to ordinary plywood, when the O 2 plasma modification time is 6 min and 12 min respectively, the wet bonding strength is increased by 75.69% and 76.27% compared to ordinary plywood; 3) when bamboo pieces are arranged in parallel, the modulus of rupture in the major direction is ~ 2 times greater than in the minor direction, while a staggered arrangement can effectively reduce the bamboo anisotropic effect; 4) the destruction of LBL mainly occurs at the joints; 5) after O 2 plasma modification, the wettability of green bamboo and yellow bamboo was significantly improved, followed by bamboo flesh. [ABSTRACT FROM AUTHOR]