The Impact of Calcination Temperature on the Chemical Composition, Physical Properties and Pozzolanic Performance of Agro-Waste Ashes

The pressing need to minimize cement-related CO₂ emissions attracted the search for agricultural waste ashes as supplementary cementitious materials (SCMs). Agro-waste ashes, rich in silica and alumina, are promising cementitious materials. However, prior researchers reported inconsistent chemical compositions and physical properties due to differences in calcination methods. This systematical review proofed the impact of calcination temperature on the chemical composition, physical properties and pozzolanic performance of agricultural waste ashes. Systematic Literature Review (SLR) following PRISMA protocols, with published articles retrieved from Scopus, Web of Science, Wiley Online Library, and Google Scholar (2014–2025) was used for the study. Using keywords, 524 published articles were first identified; after screening and eminence evaluations, 50 articles met the inclusion criteria. Data was obtained mainly on calcination methods, chemical compositions, physial properties and compliance with standards such as GS 1118 (2016) EN 197-1 (2011) and SANS 50197-1. Comparative analysis disclosed constant deficiencies in CaO (0.91–25.80%) and extreme SiO₂ (40–63%) and Al₂O₃ (10–42%) contents, particularly with open-air burning. The findings emphasized 600–700°C for 90–120 minutes as the best manufacturing window for standard-conformity of ashes derived from agro-waste materials. This review highlighted the importance of controlled calcination, identified research gaps, and provided evidence-based principles for manufacturing SCMs in construction.