Abstract: The increasing demand for sustainable construction materials has led to significant research into alternative binders that can partially replace Ordinary Portland Cement (OPC) without compromising structural performance. This study investigates the partial replacement of cement with Ground Granulated Blast Furnace Slag (GGBS) and Alccofine in mortar, focusing on mechanical and durability properties. GGBS, a by-product of the steel industry, and Alccofine, an ultra-fine supplementary cementitious material, are known for their pozzolanic and latent hydraulic properties. Various mix proportions were prepared by replacing OPC with GGBS and Alccofine. Tests conducted on fresh and hardened cement mortar included workability, compressive strength, split tensile strength, and durability assessments such as water absorption. The results demonstrated that the combined use of GGBS and Alccofine enhanced mortar performance, with improved strength development and durability due to refined pore structure and reduced permeability. This study concludes that GGBS and Alccofine are viable supplementary cementitious materials, contributing to the development of high-performance and eco-friendly cement mortar.

Keywords: Alccofine, GGBS, Supplementary Cementitious Materials, Mortar, Durability, Compressive Strength, Sustainability

| DOI: 10.17148/IARJSET.2025.12637