Filling Fresh Metakaolin‐Based Geopolymer Paste with Wood Ash: Chemical and Mechanical Characterization

Abstract Wood ash is the powdery residue remaining after wood combustion. Today, only some of the wood ashes are recycled, while most are disposed of in landfills. Increasing recycled wood ash can limit environmental damage and save transportation costs and waste disposal. This paper presents including 10% of wood ashes as a filler material for geopolymers. The ashes, coming from a local Italian restaurant, are sieved between 65 and 79 µm and are incorporated into a metakaolin‐based geopolymer matrix, cured at room temperature (25 °C). Ionic conductivity, pH, and Infrared Spectroscopy analysis, conducted after 7, 14, 28, and 56 days of curing time, reveal the occurrence of the geopolymerization process. Furthermore, the mechanical strength results allow the comparison of these materials with Portland cement, one of the most common polluting competitors.