Evaluating the Performance of Ternary Concrete Composites Incorporating Fly Ash and Ground Granulated Blast Furnace Slag as Supplementary Cementitious Materials

Abstract

Supplementary Cementitious Materials (SCMs) play a vital role in enhancing the properties of concrete through their hydraulic and pozzolanic activities. Among these materials, Ground Granulated Blast Furnace Slag (GGBFS) stands out due to its economic and performance benefits when used as a partial replacement for cement. This study investigates the effects of varying proportions of GGBFS and fly ash on the mechanical properties of concrete. A total of eight different mix designs were prepared, incorporating different ratios of fly ash and GGBFS, while maintaining a constant weight of water throughout. The GGBFS was progressively added, while the proportion of fly ash was reduced correspondingly, ensuring a combined SCM replacement of cement. Mechanical properties, specifically compressive strength and final setting time, were evaluated across the different mix proportions. Compressive strength tests were conducted at 3, 7, and 28 days to assess the development of strength over time. The results indicate that GGBFS can effectively replace up to 20% of cement when combined with 30% fly ash without compromising compressive strength compared to conventional concrete. However, it is important to note that early-age strength development was slower in mixtures containing GGBFS. These findings suggest that while GGBFS contributes to long-term durability and sustainability in concrete applications, its slower early-age strength gain may necessitate careful consideration in projects where rapid strength development is critical. Overall, the study highlights the potential of using GGBFS in combination with fly ash as a viable approach to enhance the performance of concrete, paving the way for more sustainable construction practices. Future research should focus on the long-term durability of these mixtures and explore their performance under various environmental conditions to further validate the benefits of incorporating GGBFS and fly ash in concrete formulations.