The demand for ecological materials is related to both human health and environmental aspects. Most binders are not environmentally friendly; therefore, the demand for eco-friendly binders remains high. In this work, organic lake sapropel was used as a binder, and the developed construction composite was intended for thermal insulation and construction. To improve the adhesion of wood chips to sapropel, the chips were subjected to mechanical, thermal, and chemical treatments. To improve the binding properties of sapropel, it was mechanically cleaned and activated. To optimize the properties of the composite, the wood chip-to-sapropel ratio, the pressure applied to the mixture, and the use of a hydrophobizer and a flame retardant were varied. Since organic sapropel is a colloidal substance, its maximum possible percentage used in the composite depends on the level of compression of the composite. Binder amounts ranging from 8 to 72% by mass of sapropel relative to wood chips were used to bind the composite. It was found that the amount of sapropel determines the composite's density, thermal conductivity, and compressive strength. In this work, the optimal ratio among material density, thermal conductivity, and compressive strength was determined. It was found that using 32% sapropel by mass of wood chips yields a composite density of 251 kg/m3, a compressive stress at 10% deformation of 141 kPa, and a thermal conductivity coefficient of 0.0586 W/(m·K). Using 5% of expanded graphite, a non-combustible composite was obtained, and the use of natural linseed oil and calcite lime reduced the composite's water absorption from 12% to 1.7%.

The demand for ecological materials is related to both human health and environmental aspects. Most binders are not environmentally friendly; therefore, the demand for eco-friendly binders remains high. In this work, organic lake sapropel was used as a binder, and the developed construction composite was intended for thermal insulation and construction. To improve the adhesion of wood chips to sapropel, the chips were subjected to mechanical, thermal, and chemical treatments. To improve the binding properties of sapropel, it was mechanically cleaned and activated. To optimize the properties of the composite, the wood chip-to-sapropel ratio, the pressure applied to the mixture, and the use of a hydrophobizer and a flame retardant were varied. Since organic sapropel is a colloidal substance, its maximum possible percentage used in the composite depends on the level of compression of the composite. Binder amounts ranging from 8 to 72% by mass of sapropel relative to wood chips were used to bind the composite. It was found that the amount of sapropel determines the composite's density, thermal conductivity, and compressive strength. In this work, the optimal ratio among material density, thermal conductivity, and compressive strength was determined. It was found that using 32% sapropel by mass of wood chips yields a composite density of 251 kg/m3, a compressive stress at 10% deformation of 141 kPa, and a thermal conductivity coefficient of 0.0586 W/(m·K). Using 5% of expanded graphite, a non-combustible composite was obtained, and the use of natural linseed oil and calcite lime reduced the composite's water absorption from 12% to 1.7%.