Interfacial bonding properties of the eco-friendly geopolymer-wood composites: influences of embedded wood depth, wood surface roughness, and moisture conditions

With environmental friendliness, the sustainability of natural resources, and sustainable utilization of geopolymers considered in the building industry, interfacial bonding strength of geopolymer-wood composites was enhanced environmental-friendly by increasing embedded depth of wood, sanding wood surface, and controlling moisture conditions during curing process. Beech and spruce were compared as different wood species. Pullout test was modified by using a wood veneer to determine the interfacial bonding strength of geopolymer-wood composites. It was found that geopolymer exhibited higher interfacial bonding strength with spruce rather than with beech. Interfacial bonding strength increased with an increase in the embedded depth of the wood veneer, but reaching a plateau when the depth exceeded 25 mm. A higher interfacial bonding strength caused by strong mechanical interlocking at the interface was successfully created by improving the wood surface roughness via sanding with 60-grit sandpaper. Interfacial bonding strength was higher by curing under wet conditions comparing to dry conditions. However, the influence of initial wood moisture content on the interfacial bonding strength can be ignored. The results of this study serve as the basis for better preparation of geopolymer-wood composites and a diverse application of environmentally friendly building materials.