Assessment of the Pozzolanic Properties of Gliricidia Sepium (Jacq.) Wood- Ash as a Potential Sustainable Supplementary Cementitious Material

Utilization of agricultural waste ashes as supplementary cementitious material (SCMs) have attracted increasing attention owing to their sustainability benefits, potential cementitious reactivity, and their eco-friendly attributes. However, at present, no study has been reported to assess the inherent pozzolanic properties of Gliricidia sepium wood-ash (GSA) as a SCM. This study therefore assesses the pozzolanic potential of GSA through chemical, elemental, mineralogical and microstructural characterization. Prior to the assessment through X-ray Fluorescence (XRF) analysis, X-ray Diffraction (XRD) analysis and Scanning Electron Microscopy coupled with Energy- Dispersive Spectroscopy (SEM-EDS) analysis, the wood sample was initially sun-dried, combusted, and calcined at 650 0 C for 3 hours. The result of the XRF showed that GSA is non-pozzolan, due to the combined silica oxide (SiO 2 ), alumina oxide (Al 2 O 3 ) and Iron oxide (Fe 2 O 3 ) content of 9.11%, which is below the minimum requirement specified in ASTM C618 for Class C or Class F pozzolans. Conversely, the ash contained a relatively high CaO content (51.16%), indicating that further investigation of its cementitious behaviour is required. XRD analysis identified calcite, portlandite, polyhalite, marialite, fluorapatite and tridymite as the principal crystalline phases, while SEM observations revealed angular particles with irregular pores and dense regions that may be associated with hydration products but cannot, on their own, confirm their presence. Based on the characterization conducted, GSA cannot presently be classified as a conventional pozzolanic SCM under ASTM C618. Nevertheless, its high calcium content and mineralogical composition suggest that additional performance-based tests, such as strength activity index, lime reactivity and other pozzolanicity assessments, are required to determine its suitability for cementitious applications. Healing Interiors as Experiential Knowledge Systems: Interior Green-Blue Spaces and Well-Being in Ghanaian Urban Environments Henrietta Brew Ntim-Addae1*, Victor K. Quagraine2, Rexford Assasie Oppong 3, Alexander Boakye Marful4, Aisha Ida Baffoe-Ashun 5 1,2,3,4