Recent advancements in the construction sector are paving the way for sustainable building materials, and a study led by Hongchun Xu from the School of Civil Engineering and Architecture at Zhengzhou University of Aeronautics is at the forefront of this innovation. The research, published in ‘Materials Research Express’, delves into the design and microstructural analysis of an alkali-activated fly ash-slag composite cementitious material, which promises to enhance resource utilization and reduce environmental impact.
The study investigates the optimal mixture of fly ash, slag, and coal gangue, utilizing NaOH as an alkali activator to unlock the full potential of these materials. Xu explains, “By employing response surface analysis, we were able to identify the critical factors that influence the mechanical properties of the composite material, which is essential for its application in construction.” The findings reveal that the content of NaOH, the length of basalt fibers, and their dosage significantly affect the material’s strength, with NaOH emerging as the most influential factor.
The optimal mix ratio discovered by the researchers—5 parts fly ash, 1 part slag, and 4 parts coal gangue, combined with 3% NaOH by weight, 2% basalt fiber dosage, and 3 mm fiber length—resulted in a commendable compressive strength of 8.97 MPa after 28 days of standard curing at room temperature. This level of strength indicates that the composite material could serve as a viable alternative to traditional cement, which is crucial given the ongoing push for greener construction practices.
The research employs advanced microscopic techniques such as XRD, FTIR, TG-DSC, and SEM to analyze the microstructure of the composite cementitious material. The results indicate that the hydration products, primarily consisting of gels like C-S-H, C-A-H, and C-A-S-H, are unevenly distributed, suggesting a complex interaction within the material. Xu notes, “The strong alkaline environment provided by NaOH not only initiates hydration but also enhances the bonding capabilities of the fly ash and slag, leading to a more durable material.”
The implications of this research extend beyond laboratory results. The construction industry is increasingly seeking sustainable alternatives to traditional materials, and the alkali-activated fly ash-slag composite cementitious material could meet this demand. As the industry grapples with environmental regulations and the need for lower carbon footprints, such innovations could redefine building practices and material sourcing.
Moreover, the potential for using waste materials like coal gangue presents an opportunity to reduce landfill waste while creating high-performance building materials. This aligns with global sustainability goals and could lead to cost savings for construction companies looking to adopt greener practices.
As the construction sector continues to evolve, the findings of Xu and his team may serve as a catalyst for further research and development in sustainable materials. The integration of such innovative solutions is not just a trend but a necessary step towards a more sustainable future in construction. For more information about the research and its implications, visit Zhengzhou University of Aeronautics.