Valorization of Wood Waste for Sustainable Construction: Circular Economy Approaches Using Sawdust in Cementitious Materials

The construction industry faces mounting pressure to adopt sustainable practices amid escalating wood waste generation from sawmilling and demolition activities. This review explores the valorization of sawdust, a prevalent wood waste byproduct within cementitious materials as a cornerstone of circular economy strategies. Drawing on recent literature, we examine sawdust's integration as a partial aggregate replacement, filler, or biochar precursor in concrete, mortars, and magnesium oxychloride cement (MOC) composites. Key findings highlight optimal incorporation levels of 5–20% by volume, which yield lightweight materials with enhanced thermal insulation (conductivity reduced to 0.176–0.745 W/mK) and sound absorption (coefficients up to 0.979), while maintaining compressive strengths of 17–50 MPa suitable for non-structural applications. Environmental benefits include diverted landfill waste (e.g., 64 million tonnes annually in the USA), lowered CO? emissions (up to 71% reduction compared to plywood), and carbon sequestration via biochar (870 kg CO?/ton). Challenges such as reduced workability, durability concerns in humid environments, and variability in sawdust quality are addressed through pretreatment methods like boiling or sodium silicate addition. This synthesis underscores sawdust's potential to foster resource-efficient construction, aligning with UN Sustainable Development Goals, and proposes future research on standardized protocols and life-cycle assessments to accelerate adoption.