The high global demand and a significant carbon footprint of around 8% of anthropogenic CO₂ emissions from the production of Portland cement, intensive research has been conducted on the use of supplementary cementitious materials (SCMs) from agricultural waste has been conducted. Cassava (Manihot esculenta Crantz) is a widely farmed staple food in the tropics, with an estimated amount of 20–35% of cassava tubers wasted as peel. In this review, the cassava peel ash (CPA) as a new Supplementary Cementitious Material (SCM) is critically discussed mainly regarding its physicochemical characterization, pozzolanic properties, and performance in cementitious systems.
Analysis of available literature shows that the typical CPA would contain 55.93% SiO₂, 19.88% Al₂O₃, and 6.02% Fe₂O₃ which equals a total content of pozzolanic oxides of 81.83%, which is much higher than the minimum of 70% prescribed in ASTM C618. According to the pozzolanic activity index (PAI) of CPA 75.8% is satisfactory pozzolanic reactivity. The optimum calcination temperature is 600–700°C which yields ash with a high amorphous silica content for pozzolanic reactions. Concrete with 5–15% CPA replacement has compressive strengths similar to those in control concrete at 28 days, and additional strength gain is promoted by the creation of secondary calcium-silicate-hydrate (C-S-H) formation in the concrete.
This review summarizes the current state of the art for CPA production methodologies, characterization techniques (XRF, XRD, SEM-EDS, FTIR), and how replacement levels affect the properties of fresh and hardened concrete. Moreover, it discusses standardization issues, environmental sustainability consequences and points out key research gaps preventing the commercialization of CPA for construction. The results justify the cassava peel waste valorisation as a realistic and eco-efficient SCM, especially on the African continent where the construction industry is highly developed and there is a wide range of cassava production areas.
- Quote paper
- Olabimtan Olabode et al. (Author), 2026, Cassava Peel Ash as a Supplementary Cementitious Material, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/1760574
