SOFTWOOD COMPOSITES FOR CONSTRUCTION

Abstract

The article deals with the issues of secondary use of industrial waste from the processing of soft hardwood wood. It is shown that the disposal of man-made waste in landfills is undesirable, and the use of wood waste to generate heat for heating is limited to the autumn-winter period. It is proved that it is most expedient to make composites from the waste of processing soft hardwood wood, since the need for inexpensive building materials is constantly increasing. Wood- cement materials from soft-leaved wood are practically not produced due to the presence of water- soluble saccharides, which worsen the process of hydration of cement. It is proposed to use binders that harden quickly in the production of composites made of soft hardwood. To exclude the negative influence of the extracted substances, it is proposed to use urea-formaldehyde glue as a binder. The mathematical dependence of the compressive strength of a composite made of soft hardwood on the glue consumption, wood consumption and the duration of exposure after molding is obtained. The parameters of the composite manufacturing mode are set: wood consumption-190 ... 195 kg/m3, urea-formaldehyde glue consumption-262...270 kg/m3; the duration of exposure after molding – 6 days. Methods for reducing the release of free formaldehyde from composites have been identified. It was found that in the steam-air mixture after 12 days of exposure of the chip-and- glue composite, there are no previously detected micro-impurities of formaldehyde, and the chip- and-glue composite can be used in construction without restrictions.