Mechanical Property Investigation of M40 Concrete with Supplementary Cementitious Materials: GGBS and Silica Fume

Concrete is the most widely used construction material, but the production of cement generates a large amount of carbon dioxide, contributing to environmental concerns. To address this issue, supplementary cementitious materials such as ground granulated blast furnace slag (GGBS) and silica fume (SF) can be used as partial replacements for cement. This study investigates the mechanical properties of M40 grade concrete with different replacement levels of GGBS and silica fume. Seven mixes were prepared, including a control mix, binary mixes with GGBS or SF, and ternary mixes with both GGBS and SF. Standard tests for compressive strength, split tensile strength, and flexural strength were conducted at 7 and 28 days. The results showed that GGBS improved long-term compressive strength but reduced early-age strength, while silica fume significantly enhanced both early and later strength. The ternary blend of 20% GGBS and 10% silica fume achieved the highest strength values, with 57 MPa compressive strength, 4.9 MPa split tensile strength, and 6.8 MPa flexural strength at 28 days. The study concludes that the combination of GGBS and silica fume in M40 concrete not only improves strength properties but also promotes sustainability by reducing cement consumption and carbon emissions.