The increasing demand for low-carbon concrete necessitates the development of binder systems that are capable of simultaneously ensuring structural performance and sustainability. This study presents an experimental investigation on the mechanical, structural and microstructural behavior of M30 grade concrete incorporating ternary blended binders composed of fly ash, ground granulated blast furnace slag and Alccofine. A systematic replacement strategy was adopted to identify an optimal binder composition that balances strength development and material efficiency. Mechanical properties were evaluated at 7 and 28 days, while reinforced concrete beams were tested under loading to assess load-deflection response and crack development. Microstructural analysis using scanning electron microscopy and energy dispersive X-ray analysis was performed to examine hydration morphology and interfacial transition zone characteristics. The results indicate that the optimized ternary mix achieved improvements of 19.29% in compressive strength, 33.3% in split tensile strength and 33.85% in flexural strength compared to the control mix. Structural testing showed enhanced load-carrying capacity, improved deformation response and delayed crack propagation. The findings suggest that the combined effect of particle packing, secondary hydration and interfacial transition zone refinement contributes to improved tensile behavior. In addition, the optimized mix achieved 52% clinker reduction, demonstrating its potential for sustainable structural applications.
