Fabrication and Performance of a Glue-Pressed Engineered Honeycomb Bamboo (GPEHB) Structure with Finger-jointed Ends as a Potential Substitute for Wood Lumber

The binder can improve the physical characteristics of biomass pellets by forming solid bridges and increasing the adhesion of biomass materials. Taking pine sawdust as raw material and brown sugar water with different concentration as a binder, this study adopted spraying and stirring methods, respectively, and mixed brown sugar water with biomass in diverse proportions. The characteristic of pellets such as durability, relaxation ratio and compressive strength were studied by orthogonal design. Through range analysis, BP (Back Propagation) neural network factor significance analysis and mapping the relationship between physical properties and factors according to the importance of each factor, the effect of densification variables on the physical characteristics of biomass pellets was studied, and the outcome of adding brown sugar water binder to raw material by spraying method in improving the densification quality of biomass was explored. Results showed the brown sugar water binder added to pine sawdust by spraying method could mix the binder and biomass raw material more evenly compared with the stirring method. The relaxation ratio of pellets obtained by spraying method was reduced by 13.47%. The optimal densification conditions of pine sawdust were when the compaction pressure was 100 MPa, the mass ratio of brown sugar to water was 2:1, the proportion of brown sugar water to biomass material was 3%, and the adding method was spraying.

Using bamboo to replace wood has great significance for the protection of forests. This work presents the concept of the reorganization of arc bamboo sheet to produce recombined arc-segment bamboo lumber (RABL). Several key preparation technology parameters were investigated. Results showed that when the phenol resin (PF) double-sided adhesive quantity was 250 g/m2, unit pressure was 2.0 MPa, screen voltage was 4200 V, screen current was 1.5 A, and hot pressing time was 30 s/mm, the modulus of rupture (MOR) of the RABL was 105 MPa and the modulus of elasticity (MOE) was 5000 MPa. These parameters mean that RABL could be used as the structural material for load-bearing situations. If ignoring the machining allowance, the bamboo utilization rate of the RABL was 1.72 times that of the rectangular element recombinant bamboo and the adhesive level of the RABL was 0.6 times that of the rectangular element recombinant bamboo. When considering the machining allowance, the bamboo utilization rate of the RABL was 1.8 times that of the rectangular element recombinant bamboo, and the adhesive volume of the RABL was 0.56 times that of the rectangular element recombinant bamboo, so RABL has obvious advantages.