Physicochemical evaluation of Eucalyptus Wood Ash as a mineral admixture in Portland cement matrices: A preliminary study

Abstract

This study explores the physicochemical properties of EWA from broiler farm furnaces as a potential mineral admixture in Portland cement matrices, aiming to provide a sustainable alternative for waste disposal. Two EWA preparation procedures were assessed with the goal of proposing an optimal preparation protocol, beginning with an initial sieving process. These procedures included grinding for varying durations (0.5, 1, 2, and 3 hours) and calcining at different temperatures (600, 700, and 800ºC) using a two-step strategy. The optimal Strength Activity Index (SAI) results indicated that EWA ground for 3 hours (EWA-3h) performed the best, likely due to the enhanced pozzolanic reaction and pore-filling capacity associated with finer particles. Consequently, EWA-3h was selected for physicochemical characterization and preliminary studies in cement matrices. Rietveld refinement identified calcite and portlandite as the major components of EWA-3h, suggesting its potential to enhance cement performance. Although EWA-3h is not classified as a pozzolan, its physicochemical profile, characterized by high crystallinity, supports its use as an inert mineral admixture in cementitious composites. However, pH analysis categorized EWA-3h as hazardous due to its potential corrosivity, underscoring the importance of proper disposal, such as incorporation into cementitious matrices. The findings suggest that EWA-3h could enhance the sustainability of cement composites by partially replacing cement, potentially improving the microstructure and reducing CO2 emissions. Furthermore, the preliminary study indicates that replacing 3 % of cement with EWA-3h is technically feasible, achieving a compressive strength of 30 MPa while maintaining good workability, as indicated by a consistency index of 205 mm. The inclusion of EWA-3h also preserved the density and dynamic modulus of elasticity (DME) within ranges very close to the reference values (2002 kg/m³ and 5.96 GPa), exhibiting even less variability. However, further studies are essential to confirm its safety, particularly regarding potential alkali-aggregate reactions due to EWA-3h's elevated potassium content. This research links agribusiness waste management with construction material production, promoting sustainability by transforming potential hazards into valuable resources.

Keywords

• Mineral admixture
• Eucalyptus Wood Ash
• Residue incorporation
• Filler effect
• Nucleation