Valorisation of wood fibre waste in gypsum composites for green building applications

The construction sector significantly contributes to environmental degradation due to its high consumption of non-renewable resources and carbon emissions. This study presents the development of a gypsum-wood waste biocomposite, as innovative and sustainable material for construction applications. The research investigates the incorporation of this abundant yet underutilized industrial by-product into a gypsum-based matrix, aiming to reduce environmental impact. The wood fibre waste was reused without pre-treatment, ensuring a simple and scalable production process. Experimental results indicate that increasing wood waste content progressively reduces thermal conductivity, from 0.35 W/mK to 0.24 W/mK, significantly improving insulation properties. Simultaneously, density decreases from 950 kg/m³ to 720 kg/m³, making the material lighter and easier to handle. However, a trade-off is observed in mechanical performance, as compressive strength decreases from 8.5 MPa to 3.0 MPa at the highest wood waste content of 10 wt.%. Despite this, mixtures containing 2–4 wt.% wood waste maintain mechanical strengths between 4.8 and 6.2 MPa, making them suitable for non-structural applications such as insulating panels and eco-friendly plasters. Additionally, preliminary virtual modelling and energy simulation were implemented to isolate the energy contribution of the produced mixes in a building model under Mediterranean-Continental climatic conditions (represented by the city of Rome). Also, a multi-criteria analysis was implemented to rank the produced mixes and identify the optimal compromise between material’s functional performance, environmental impact, and economic feasibility. Obtained results highlight that the optimal formulation balances insulation efficiency and mechanical properties while minimizing environmental and economic drawbacks. The direct reuse of untreated wood fibre waste enabled the development of lightweight gypsum bio-composites with improved insulation performance suitable for non-structural building applications. Finally, the best performing formulation was benchmarked against commercial product to investigate the possible positioning of the proposed biocomposite. This bio-composite represents a viable alternative to conventional materials, aligning with circular economy principles and European sustainability policies such as the Green Deal and Renovation Wave.