Standard building practices commonly use gypsum-based drywall panels on the interior wall and ceiling applications as a partition to protect the components of a wall assembly from moisture and fire to uphold the building code and ensure safety standards. Unfortunately, gypsum-based drywall panels have poor resistance to water and are susceptible to mold growth in humid climates. Furthermore, the accumulation of drywall in landfills can result in toxic leachate impacting the surrounding environment. A proposed solution to the pitfalls of gypsum-based drywall arises in its substitution with a new lightweight composite honeycomb sandwich panel. This study aimed to develop sandwich panels with improvements in flexural strength and thermal insulating properties through the combined use of cementitious binder mix and kraft-paper honeycomb structures. The proposed alternative is created by following standard practices outlined in ASTM C305 to create cement panels and experimenting with admixtures to improve the material performance in order to cater to a drywall panel application. The kraft-paper honeycomb structure is bonded to cured cementitious panels to create a composite “sandwich panel” assembly. The results indicate that the sample flexural strength performed well after 7 days and exhibited superior flexural strength at 28 days, while providing a substantial increase in R-value of 5.84 m²K/W when compared to gypsum-based panels, with an R-value of 5.41 m²K/W. In addition, the reinforced kraft-paper honeycomb with a thick core and addition of flax fibres to the cementitious boards possesses better thermal conductivity, with a reduction of 42%, a lower density, and a lower water vapour transmission in comparison to the thin kraft-paper honeycomb sandwich panel.

This research has demonstrated that SiO₂ impregnation under high vacuum pressure of -90 kPa can significantly reduce porosity by almost 10%, and improve mechanical and viscoelastic properties of spruce wood under dry and saturated states. Characterization methods, such as Impact test, DMA, SEM, EDS, Porosity and SAXS tests were conducted on non-treated and -90 kPa treated spruce wood samples under dry, saturated and submerged states to analyze the synergistic effect of high vacuum SiO₂ impregnation pressure on wood’s properties. The results showed that high vacuum impregnation pressure had a significant positive reinforcing effect on wood’s properties. It increased the impact resistance of wood under dry and saturated conditions. Additionally, the high vacuum impregnation technique was able to overcome the water-induced softening effect and caused a significant increase in the Storage modulus through uniform dispersion of the SiO₂ particles in the wood’s vascular structure. Consequently, the impregnation reinforced the wood, and ameliorated its capacity to absorb energy. High vacuum impregnation was also able to counteract the plasticizing effect of the water molecules and significantly increased the Loss modulus by increasing the internal friction and cohesion of the wood components with the addition of the nanoparticles to the vascular system, which increased the wood’s capacity to transform and dissipate energy. Quantitatively and qualitatively, impregnation under a vacuum pressure of -90 kPa exhibited an effective obstruction of the vascular structure of spruce wood. In all conditions, high vacuum impregnated samples showed significant enhancements over non-treated samples. This research demonstrated that high vacuum SiO₂ impregnation is an effective wood processing techniques. Multiple materials and applications could benefit from this research wherein high strain-rate deformations is expected to occur or when simultaneous elastic behaviour of wood and its damping energy is needed. This study could also pave the way for research on the synergistic effect of SiO₂ impregnation and water absorption on the viscoelastic behaviour of wood.