CHANGE OF STRENGTH INDICATORS OF TIMBER UNDER THE INFLUENCE OF AN AGGRESSIVE ENVIRONMENT

Abstract

A detailed analysis of literature sources on the study of solid timber of deciduous and coniferous species under the influence of various aggressive environments, in particular, water, acid, and alkaline, is given. A method of experimental studies of timber by Axial compression along fibers with a short-term load when working in an aggressive environment with an increase in displacement is developed. The terms of impregnation of deciduous and coniferous timber species (birch and pine) in aggressive environments, in particular, in hydrochloric (15%), acetic (9%) and lactic acids (40%), are given. The timber was soaked naturally without additional stimulation for 7, 30, and 90 days, respectively. These tree species are grown in the forests of the Volyn region. The trees were approximately 60 years old at the time of testing. Production of samples was carried out in accordance with current standards. Timber that was tested before being impregnated with various liquids had a standard humidity of 12%. The timber was soaked naturally without additional stimulation for 7, 30, and 90 days, respectively. Penetration of liquids into the thickness of the samples was performed in a vessel in a horizontal position when completely immersed in various solutions. At the same time, each solution was provided with access to all sides of the prisms. The total number of prisms tested was 78 PCs. Experimental studies were carried out on a servo-hydraulic testing machine STM-100. The deformation rate of prisms was 1.5 mm/min. The results of ultimate strength studies are presented, taking into account the aggressiveness factor of the medium. It was found that the effect of different acids on timber with different impregnation periods significantly reduces its strength indicators, in particular hydrochloric by 42,0%, acetic – by 21,9%, lactic – by 32,7%.