Fire-resistant wood by impregnation with cement

The impregnation of wood with cement-based fire retardants has shown inconsistent results, highlighting the need for process optimisation. Variations in effectiveness and significant deviations in mass change affect fire tests, particularly in the fire chamber and fire shaft. Thicker components can perform better and achieve B1 fire classification. The challenge is to optimise process parameters to minimise variability and achieve consistent, improved fire resistance. Further investigation were essential to clarify these factors and validate potential improvements.

The Portland cement in the wood contains bound water which is released when the wood is heated, drawing heat from the flames. The hydration creates a strong anchor that increases resistance to leaching. Aluminum-hydroxide releases water when heated, while calcium oxalate monohydrate decomposes in an endothermic process, releasing water, carbon dioxide and carbon monoxide. The process with carrier liquid and subsequent storage in water allows the use of flame retardants that were previously unsuitable.