# Thermal Conductivity and Thermal Behavior of Mortar Containing Wood Shavings and Sawdust
This raw material is the primary input for sawmills and wood-processing industries, where it is converted into lumber and other products. During this process, a significant portion of the roundwood volume is converted into by-products such as wood shavings, sawdust and chips. As a secondary biodegradable raw material being incorporated in concrete mixes, wood sawdust and shavings can be effectively repurposed, reducing the need for natural aggregates. Their inclusion can also improve thermal insulation, which may enhance the overall energy efficiency of the resulting structures [5; 7; 8]. Papers report that the preferred method for the natural aggregate was a volumetric replacement [9], either most commonly as a percentage [10; 11], or as a ratio [12]. The physical and mechanical properties of the wood sawdust and shavings differ depending on the geographical origin of the wood, the type of wood, the part of the tree they are derived from and the method of production. Timber has been a preferred construction material for many centuries due to its physical and mechanical properties, particularly its insulating properties. Considering this, when used as a concrete composite material, researching these same properties poses a significant scientific interest. For that reason, researchers such as [13; 14] have focused on the evaluation of the thermal conductivity of concrete containing sawdust in different sizes. In addition to the benefits mentioned above, the inclusion of wood sawdust and shavings in concrete can enhance its acoustic performance, making it a valuable material for residential buildings where sound insulation is important [7]. However, the incorporation of wood sawdust and shaving in concrete causes a reduction in the mechanical strengths [15]. Moreover, treated and untreated wood exhibit differences in performance and are overall susceptible to biodegradation due to their organic nature, especially when exposed to high moisture environments, consequently affecting the durability of the composite material [11; 16; 17; 18; 19; 20; 21]. In order to mitigate these challenges, the wood byproducts are often treated, increasing the difficulty of utilization as well as the cost [20]. The treatment used by [PERSON] et al. [20] consisted of boiling the shavings in water for four hours, as the authors expected that this would be enough to change the chemical composition of the wood and thus eliminate the organic matter. [PERSON] et al. [21] investigated the effect of aging cycles (wet-dry cycles and freeze-thaw cycles) as well as the effect of thermal shock to determine the thermal compatibility of wood and cement matrix. The conditions imposed on the specimens were aggressive, with a temperature range of about 85 \({}^{\circ}\)C. The lack of visual damage shows that the material remains structurally stable under typical thermal shocks, which supports the idea of moderate thermal compatibility. The issue of durability should be further investigated as a continuation of existing research. Changes in components of concrete or mortar has, as a result, a change in the thermal properties of concrete. Since aggregate comprises about 60-80% of the volume of concrete, the type of aggregate affects the thermal conductivity coefficient. It has been reported that the thermal conductivity of lightweight concrete ranges from 0.2 to 1.9 W/m \({}^{\circ}\)K and from 0.6 to 3.3 W/m \({}^{\circ}\)K for normal weight concrete [22]. It depends upon a variety of factors such type of aggregates, silica content, water to cement ratio, density, etc. Wood exhibits a low thermal conductivity (high heat-insulating capacity). The thermal conductivity of wood is highest in the axial direction and increases with density and moisture content; thus, it has a wide variation. [PERSON] et al. [7] investigated the possibility of chemical interactions between wood sawdust and concrete matrix and concluded that sawdust particles exhibited no chemical interaction with the host concrete matrix.