UTILIZATION OF SUGARCANE BAGASSE ASH AS SUPPLEMENTARY CEMENTITIOUS MATERIAL IN CONCRETE

Cement-based composites (CBCs) are crucial in construction, but their production is fraught with environmental concerns, including high energy consumption, CO₂ emissions, and resource depletion. To address these issues, researchers are increasingly turning to supplementary cementitious materials (SCMs) to reduce cement use and its associated environmental impact. Sugarcane Bagasse Ash (SCBA), a byproduct of sugar production, has garnered attention as an effective SCM. Produced from burning sugarcane bagasse for energy, SCBA is often relegated to landfills, posing environmental hazards. However, its incorporation into cementitious materials not only mitigates waste disposal problems but also enhances the sustainability of construction practices by promoting a circular economy and reducing the carbon footprint of the cement industry. This thesis investigates the potential of SCBA that was obtained from Texas-based sugarcane industry as a Class F pozzolan replacement in concrete, emphasizing its physical and chemical properties and their effects on concrete mechanical and durability performance. Initial assessments revealed that raw SCBA, with its high moisture content and 15.39% loss on ignition, necessitates processing to meet ASTM standards. Cement mortar containing sieved SCBA (passing 75 μm sieve size) exhibited enhanced workability and reduced superplasticizer demand compared to concrete containing un-sieved SCBA. Heat flow results indicated a delay and reduction in peak heat flow with SCBA, beneficial for mitigating thermal cracking in mass concrete applications. Compressive strength tests showed that while SCBA mixes initially had lower strength compared to control mixes, the strength difference was less significant by 28 days, particularly at 5-10% replacement levels. Further, dynamic modulus of elasticity and drying shrinkage measurements confirmed SCBA's potential, with moderate replacement levels (5-10%) offering an optimal performance balance. SCBA's inclusion also reduced alkali-silica reaction expansion at a low SCBA replacement (5 %); any higher SCBA replacement levels, however, turned out to be less effective in ASR control, likely due to the contaminants in the SCBA. Overall, the study identifies 5-10% sieved SCBA as the optimal replacement level, maximizing sustainability, mechanical and durability performance in cementitious system. As a greener substitute for conventional SCMs like fly ash, processed SCBA has the potential to be employed as a feasible SCM in areas where sugarcane is produced in large quantities.