In a significant advancement for the construction sector, researchers from Henan Polytechnic University have unveiled promising findings regarding the utilization of hemihydrate phosphogypsum (PG) pretreated with calcium hydroxide (CH). Their study, led by Liya Zhao, explores the incorporation of blast furnace slag (BFS) to enhance the mechanical properties and microstructure of this sustainable building material. This research, published in the journal ‘Case Studies in Construction Materials’, addresses a pressing challenge: while PG pretreatment with CH mitigates environmental pollution, it often compromises mechanical strength, limiting its application in construction.
Zhao emphasizes the dual benefit of their findings, stating, “By integrating blast furnace slag, we not only prolong the setting time of phosphogypsum but also significantly enhance its mechanical properties and water resistance.” The results are compelling. Samples containing 40% BFS demonstrated a remarkable increase in mechanical strength, achieving 15.7 MPa at 28 days—an impressive 2.7 times the strength of the reference sample. This enhancement opens doors for wider utilization of PG in construction, a material often sidelined due to its perceived limitations.
The study delves deeper into the microstructural changes facilitated by BFS. The introduction of new phases, such as ettringite (AFt) and calcium alumino silicate hydrate (C-A-S-H) gel, alters the crystallization behavior and morphology of gypsum. This transformation not only contributes to a denser microstructure but also encapsulates AFt and gypsum, enhancing overall durability. Zhao notes, “The changes in the hydration environment due to BFS incorporation play a crucial role in optimizing the performance of phosphogypsum, making it a more viable option for sustainable construction.”
As the construction industry increasingly seeks eco-friendly alternatives, the findings from this study could significantly shape future developments. The ability to repurpose industrial by-products like BFS not only addresses waste management challenges but also aligns with global sustainability goals. By optimizing PG through BFS integration, the construction sector can potentially reduce its carbon footprint while enhancing material performance.
This innovative approach to utilizing waste materials represents a pivotal step towards more sustainable building practices. With continued research and application, the insights from Zhao and her team could pave the way for broader acceptance and use of phosphogypsum in construction, ultimately contributing to a greener future.
For more information on this research and the team’s work, visit School of Materials Science and Engineering, Henan Polytechnic University.