In the quest for sustainable infrastructure, a groundbreaking study led by Yasmin R. Hamed of the Structural Engineering Department at Mansoura University, Egypt, has shed new light on the potential of geopolymer concrete as a green alternative to traditional Portland cement. Published in the journal Infrastructures, the research delves into the performance of geopolymer concrete made from silica fume (SF) and fly ash (FA), utilizing different alkaline activators (AAs) to optimize its mechanical and microstructural properties.
The study, which examined twelve different geopolymer concrete mixes, revealed that increasing the SF content significantly improved the workability of the concrete. “The slump of geopolymer concrete steadily increased with higher SF content, showing a 120% improvement at 100% SF content,” Hamed noted. However, the compressive strength only improved with up to 20% SF, indicating a trade-off between workability and strength. This finding is crucial for the energy sector, where the durability and longevity of infrastructure are paramount. By optimizing the SF content, engineers can create more sustainable and durable structures that require less maintenance and have a lower environmental impact.
The research also explored the use of different alkaline activators, including sodium hydroxide (SH), potassium hydroxide (PH), and sodium silicate (SS) solutions. The results showed that geopolymer concrete with PH as the alkaline activator exhibited up to 13% lower compressive strength compared to SH. This insight is particularly relevant for the energy sector, where the choice of alkaline activator can significantly impact the performance and cost-effectiveness of geopolymer concrete in large-scale infrastructure projects.
One of the most compelling findings of the study was the identification of the optimal mix for geopolymer concrete. Mix G3, which included specific proportions of SF, FA, sand, stone, SS, SH, and water, demonstrated the best mechanical performance, including compressive, tensile, and bending strengths. This mix also showed a slump value of 115 mm, making it suitable for structural applications. “Mix G3 in this study demonstrated the best mechanical performance, including compressive, tensile, and bending strengths,” Hamed explained. This discovery could revolutionize the way geopolymer concrete is used in the energy sector, enabling the construction of more resilient and sustainable infrastructure.
The microstructural analyses revealed that some partially reacted and unreacted FA particles, as well as some voids, were detected when using 100% FA in geopolymer concrete. In geopolymer concrete incorporating 100% SF, there were notable pores, large cracks, incomplete geopolymerization, and numerous sharp crystalline peaks. These findings highlight the importance of optimizing the composition of geopolymer concrete to achieve the desired mechanical properties and durability.
As the energy sector continues to seek sustainable solutions, the insights gained from this research could shape future developments in the field. By understanding the performance of geopolymer concrete with different alkaline activators and SF content, engineers can design more efficient and environmentally friendly infrastructure. This could lead to a significant reduction in carbon emissions and a more sustainable future for the energy sector. The study, published in Infrastructures, provides a comprehensive analysis of the mechanical and microstructural properties of geopolymer concrete, offering valuable insights for researchers and practitioners alike.