In the quest for sustainable construction materials, a team of researchers led by Menglim Hoy from the School of Civil Engineering at Suranaree University of Technology in Thailand has made significant strides. Their work, published in the journal “Case Studies in Construction Materials” (translated as “Case Studies in Building Materials”), explores the potential of geopolymer mortars, offering a promising alternative to traditional cement-based materials.
The study focuses on the effects of alkaline activation on geopolymer mortars synthesized from fly ash and calcium carbonate sludge, an underutilized industrial by-product. “We aimed to create a sophisticated hybrid binding system that could leverage the benefits of both fly ash and calcium carbonate sludge,” Hoy explained. The team systematically examined key parameters such as NaOH molarity, sodium silicate-to-sodium hydroxide ratio, fly ash-to-calcium carbonate sludge ratio, and liquid-to-binder ratio to optimize the performance of these mortars.
The results were impressive. Several mix designs exceeded the reference cement mortar strength of 24.5 MPa, demonstrating the potential of these geopolymer mortars to meet or even surpass the performance of traditional materials. Higher NaOH concentrations consistently produced shorter setting times and enhanced compressive strength, while incorporating calcium carbonate sludge resulted in more homogeneous microstructures.
Microstructural analysis revealed denser matrices at higher NaOH concentrations, particularly in specimens containing both fly ash and calcium carbonate sludge. “The incorporation of calcium carbonate sludge not only enhances the mechanical properties but also contributes to a more sustainable construction process,” Hoy noted.
The study also uniquely integrates machine learning techniques, specifically XGBoost and SHAP analysis, to predict compressive strength. This approach revealed that the sodium silicate-to-sodium hydroxide ratio was the most influential parameter, followed by NaOH molarity. Such insights could pave the way for more efficient and cost-effective production processes.
The implications for the energy sector are significant. As the world shifts towards more sustainable practices, the demand for eco-friendly construction materials is on the rise. Geopolymer mortars, with their lower carbon footprint and enhanced performance, could play a crucial role in this transition. “Our findings highlight the potential for optimizing geopolymer mortar performance through careful control of composition and processing parameters,” Hoy said. “This could lead to more sustainable and efficient construction practices in the future.”
The research not only advances our understanding of geopolymer mortars but also opens up new avenues for the utilization of industrial by-products. By transforming waste materials into valuable resources, this study contributes to a circular economy and underscores the importance of sustainable innovation in the construction industry. As the world continues to grapple with environmental challenges, such advancements are more critical than ever.