Abstract
<jats:p>The paper considers the prospects of using flax fibre additives to improve the physical and mechanical properties of building composites. The authors note that a regulated approach to the preparation of reinforcing additives from plant raw materials contributes to improving the performance characteristics of gypsum-based building materials. It has been established that the addition of 1-3% flax fibre with a moisture content of 18-20% to G3 gypsum significantly (by 83%) increases the flexural tensile strength of samples obtained from hardened gypsum mixtures and more than doubles the compressive strength of finished composites. The authors identified a positive effect of the degree of preliminary grinding of flax fibre (up to 50-70° on the Shopper-Rigler scale), mixed with gypsum (G3 grade) and water, on achieving the strengthening effect of the finished composites. The development of such materials complies with modern regulatory and legislative requirements in the field of sustainable construction and environmental protection.</jats:p>