Development of wood-geopolymer composites for masonry units: Effect of alkaline solution ratio and wood type

The construction industry significantly impacts the environment through greenhouse gas emissions and extensive consumption of natural resources. Repurposing waste wood into innovative construction materials, such as masonry units, offers promise in mitigating these effects. Waste wood possesses favorable properties for masonry block production, including good energy absorption, desirable heat and sound insulation, and lightweight nature. Using a sustainable binder, such as a geopolymer, could further enhance the overall sustainability of these materials, allowing for rapid development of strength, improved durability, and heightened protection against fire and weathering effects. Accordingly, this study explored the feasibility of producing wood-geopolymer composites (WGC) suitable to produce masonry units. Through rigorous experimentation, a mix design chart for low workable WGC was developed, facilitating controlled workability in the production process. Additionally, it was observed that the viscosity of the sodium silicate significantly affected the workability of WGC, particularly at low workability. Furthermore, the study found that increasing the relative sodium silicate ratio from 1.56 to 2.00 resulted in an approximately 20% increase in compressive strength. This highlights the importance of binder composition in optimizing the mechanical properties of WGC masonry units. Moreover, it was discovered that both wood chips and wood shavings demonstrated comparable effects on the workability and strength of WGC, indicating potential flexibility in utilizing different forms of waste wood in the production process.