Spruce chips stabilization in wood-cement materials: Effect of matrix composition

Abstract

The problem of the presented research is stabilization of spruce chips in modified cement matrix of wood-cement composites and analysing the effect of the stabilisation on selected parameters of these composite materials. The matrix has an impact on the stabilization of the spruce wood content. Silicate matrix based on Portland and blended cement was modified by finely ground thermal power plant slag (TPPS) and limestone (LS). Four types of wood-cement composite were subjected to water immersion tests for 28 days. During water immersion, both swelling in thickness and mass changes were analysed. The amount of sugars and pH in leachate were determined after 7 day intervals. Mechanical properties and microstructures were analysed before and after water immersion. Different behaviour with regard to spruce chips stabilization was proved in dependence of wood-cement matrix modification. Differences in thickness, swelling and sugar leach indirectly indicate the influence of the wood-cement composites matrix composition on the stabilization of spruce chips contained in this matrix. Boards with the matrix modified with thermal power plant slag showed the highest thickness swelling (%) and sugar leaching (0,042 %). Therefore, in the presence of thermal power plant slag modified matrix, spruce chips are more susceptible to sugar leach. The results of strength characteristics confirmed that sugars leached during hydration and after longer contact of wood-cement composites with water have no negative influence in their final properties in the case of all materials tested (reference and modified).