Age Dependent Properties of Concrete Incorporating Mechanically Processed Ultra-Fine Sugarcane Bagasse Ash

Abstract

This study investigates mechanically processed ultra-fine sugarcane bagasse ash (SCBA) as a partial cement replacement, addressing knowledge gaps in its long-term performance without calcination. Unlike previous research focusing on calcined SCBA, this study utilizes high-temperature boiler conditions to bypass additional calcination, enhancing pozzolanic potential through mechanical grinding. The research evaluates mechanical properties (compressive, split tensile, and flexural strength), sulphate resistance, long-term performance, and optimal replacement proportions. Concrete mixes were produced with SCBA substituting cement at 0%, 10%, 15%, 20%, and 25% by weight. Results demonstrate that 15% SCBA replacement optimizes early-age strength, while 20% replacement excels at later ages due to high silica content, fine particle size, and pozzolanic reactivity forming additional C-S-H gel. Beyond 20%, strength diminishes, establishing a clear substitution threshold. The 20% SCBA mix exhibited superior sulphate resistance by refining pore structure and reducing permeability, thereby minimizing ettringite and gypsum formation. SEM and EDS analyses confirmed denser microstructures and reduced deterioration in these mixes. Sustainability assessments revealed an 18.02% reduction in embodied energy and lower CO2-equivalent emissions with 20% SCBA replacement, attributed to decreased cement consumption and waste valorization. This mix also improved the sustainability index while maintaining acceptable workability. These findings position uncalcined SCBA as a viable low-carbon, energy-efficient alternative in concrete production, advancing sustainable construction through agricultural waste integration. The study offers a holistic analysis of SCBA's mechanical, durability, and environmental impacts, providing a practical solution for reducing the construction industry's carbon footprint.

Keywords: Sugarcane Bagasse Ash, Sustainable construction, Global Warming Potential, Long-term performance, Sulphate Resistance