Сonstructional lumber from wood of pine dead trees

The article presents the main results definition of indicators of the physical and mechanical proper ties of wood, obtained as a result of experimental studies on interstate ISO and GOST standards on small «clean» wood samples with a moisture content of 12% from pine non-weakened by drying and standing deadwood. Presented density indices according to ISO13061-2 of pine not weakened by drying and deadwood from stands of drying groups I, II and III are determined on the basis of experimental studies. The dependence of the Young's modulus on the density of wood is obtained, which is described by equations for wood non-weakened by drying and deadwood from stands of I, II, and III drying groups. To establish the main characteristics of the strength and stiffness of pine wood as a material, experimental studies were carried out to determine the effect of heat treatment temperature (77 and 120 °C) on the mechanical properties of wood, namely: tensile strength and modulus of elasticity under static bending, as well as ultimate compressive strength along the fibers. Experimental studies were carried out on samples of pine not weakened by drying and deadwood from stands of groups I, II, and III drying according to the methods of ISO13061-4, ISO13061-3 and ISO 13061-17. It has been established that the strength and stiffness indices of wood samples from stands of I group of drying and non-weakened by drying treated at temperatures of 77 and 120 °C differ slightly – within 1–5%, which allows us to consider such wood as a structural material. The regression equations are presented for the dependence of the tensile strength for static bending on the elastic modulus for the static bending of pine not weakened by drying and deadwood of I group of drying.