Water Absorption of Thermally Modified Wood Filler of Thermal Wood-Cement Composition

In this article, the technological aspects of obtaining a new effective composite material based on thermally modified wood filler and cement binders – thermal wood concrete – are considered. The influence of water content in thermally modified wood filler on the qualitative characteristics of a wood-cement composition has been studied. To solve the theoretical problems and applied issues of forecasting the technological parameters for the production of thermal wood-cement composition, the mathematical models of the effect of soaking duration and water temperature on the relative change in the mass (dampening) of the filler have been developed. At the initial stage, experimental studies have been carried out to determine the effect of pre-soaking the filler on the curing of thermal wood concrete and the quality of the resulting material. The samples have been produced via vibrocompression of a semi-dry mixture using dry and pre-soaked filler made of thermally modified wood, as well as via vibratory casting. The regularities of moisture transfer between the filler and the cement-sand mortar have been determined, and it has also been established that pre-soaking the thermally modified filler has a positive effect on the strength and quality characteristics of thermal wood concrete. On the contrary, the use of the dry filler made of thermally modified wood in this molding method has a significant negative impact on the quality of the finished material. The process of moisture absorption by the thermally modified wood filler by soaking has been studied separately. The main regularities and features of water sorption by the filler have been established at the time intervals of 30, 60, 120, 180 and 300 minutes and at the water temperatures of 3–4, 16–18 and 75–85 ℃. It has also been determined that additional water heating significantly accelerates the intensity of water sorption and the degree of dampening of thermally modified wood fillers, and the size of their particles does not play a significant role in the process. In this case, the recommended duration of soaking the thermally modified wood filler before preparing the mixture and molding the products made of thermal wood concrete via semi-dry vibrocompression is 30 minutes.