Experimental Investigation of the Thermo-Mechanical Performance of High-Strength Self-Compacting Concrete Incorporating Bagasse ash

Abstract

The environmental impact of Portland cement production has intensified the need for sustainable supplementary cementitious materials in high-performance concrete. While bagasse ash has been explored in conventional concrete, experimental data on the thermo-mechanical performance of high-strength self-compacting concrete incorporating bagasse ash under elevated temperature conditions remain limited. This study experimentally investigates the thermo-mechanical behaviour of HSSCC with bagasse ash as a partial replacement for Portland cement. Bagasse ash was calcined at 550 °C, finely ground, and incorporated at replacement levels of 0–10% by mass, while maintaining a constant binder content of 600 kg/m³ and a water-to-binder ratio of 0.29. Fresh properties were evaluated using slump flow, V-funnel, and L-box tests, while compressive strength was measured up to 42 days. Thermal performance was assessed through controlled furnace exposure, and microstructural characteristics were examined using SEM–EDS. All mixes satisfied self-compacting concrete workability requirements. Elevated temperature exposure reduced compressive strength due to dehydration and thermal microcracking; however, increasing bagasse ash content significantly enhanced residual strength. The 10% replacement level achieved the highest residual compressive strength of 14.00 N/mm² at 42 days. The findings demonstrate that bagasse ash enhances the thermo-mechanical performance and fire resistance of high-strength self-compacting concrete while reducing cement consumption, supporting its application in sustainable and fire-resilient structural concrete.