Today, December 11th, 2023, Rožle Repič successfully defended his doctoral dissertation entitled: SYNERGISTIC EFFECTS OF THERMAL MODIFICATION AND MINERALIZATION ON WOOD PROTECTION AGAINST BIOLOGICAL DEGRADATION AND FIRE
Summary of the doctoral dissertation:
This study discusses the combined approach and synergistic effects of thermal modification (TM) and mineralization on properties related to the biological and fire resistance and other relevant properties of wood. Two types of wood, namely beech (Fagus sylvatica) and spruce (Picea abies), were either 1) thermally modified, 2) mineralized using a calcium-based preparation or 3) treated using both procedures. Wood mineralization is an environmentally friendly process, which has been shown to incorporate up to 18,6 wt. % carbonates into the wood through the impregnation process. We have shown experimentally that the mineralization of TM wood is both feasible and sensible, and that leaching of carbonates from the wood is negligible. TM improves the resistance of wood to decay fungi, whereas the effect of mineralization is less significant. The colonisation of micro-organisms on the outer surface of the exposed wood is significantly lower on mineralized wood than it is on untreated wood or that which has been thermally modified. Following thermal modification and/or mineralization, the mechanical properties of the wood are impaired. The dimensional stability is also adversely affected by mineralization, but this effect is far less pronounced when the mineralization is combined with TM. Mineralization also improves the fire performance of wood, which is otherwise impaired by thermal modification. A combination of the two modification processes, however, results in the best fire performance.