Agricultural Waste as a Sustainable Cement Substitute in Construction Materials: A Comprehensive Review of Properties and Future Prospects

The cement industry contributes approximately 7–10% of global carbon dioxide (CO2) emissions, highlighting the need for sustainable alternatives to conventional Portland cement. Agricultural waste has emerged as a promising supplementary cementitious material because it is abundant, renewable, and rich in pozzolanic compounds. This review evaluates the potential of agricultural waste as a sustainable cement substitute by examining its material properties, treatment methods, engineering performance, and future prospects. A systematic literature review was conducted using peer-reviewed articles. The findings indicate that the performance of agricultural waste depends on its chemical composition, calcination conditions, grinding process, and pretreatment methods. Properly processed agricultural wastes, including rice husk ash, sugarcane bagasse ash, palm oil fuel ash, and corn cob ash, can partially replace Portland cement while improving compressive strength, durability, and microstructure. In addition, their use reduces agricultural waste disposal and lowers the carbon footprint of construction materials. However, differences in processing techniques, material characteristics, and testing methods remain major challenges for large-scale application. This review provides a comprehensive comparison of different agricultural wastes. It highlights the need for standardized processing methods and further research to support their wider adoption in sustainable and low-carbon construction.