Utilization of cassava starch bagasse ash as a supplementary cementitious material in mortars: characterization and mechanical performance

The construction industry seeks sustainable alternatives to reduce Portland cement consumption and mitigate the environmental impacts associated with its production. In this context, this study investigates the use of cassava starch bagasse ash (CSBA) as a supplementary cementitious material in mortars. The residue was obtained from an industrial cassava processing facility and subjected to drying, grinding, and calcination at 650°C for two hours. Subsequently, pozzolanic activity tests and physicochemical characterizations were performed, along with an evaluation of the influence of partial cement replacement (5% and 10%) on the physical and mechanical properties of the mortars. The results indicated that CSBA did not exhibit significant pozzolanic behavior according to standardized criteria. However, its incorporation at 5% retained 97.64% of the compressive strength of the reference mix while remaining within recommended absorption limits. Additionally, an increase in water absorption and void index was observed as the replacement level increased, impacting mechanical strength. The 10% replacement led to a significant reduction in both compressive and tensile strength, suggesting that higher substitution levels may compromise structural performance. Thus, a 5% replacement of cement with CSBA demonstrated potential for non-structural concrete applications, contributing to the valorization of agro-industrial waste and the reduction of the carbon footprint in the construction sector. Future studies should explore alternative thermal treatments to enhance CSBA reactivity, as well as its application in structural concretes and long-term durability assessments.