In a significant advancement for sustainable construction practices, researchers have unveiled a novel approach to utilizing construction waste by combining recycled brick powder (RBP) with circulating fluidized bed fly ash (CFBFA) to create an innovative earthwork subgrade backfill material. This groundbreaking study, led by Wenhuan Liu from the College of Materials Science and Engineering at Xi’an University of Architecture and Technology, addresses pressing environmental concerns associated with waste management in the construction industry.
As urbanization continues to accelerate, the construction sector faces increasing scrutiny over its resource consumption and environmental impact. Liu’s research offers a promising solution by effectively repurposing two types of solid waste—RBP and CFBFA—into a high-performance backfill material. “Our findings demonstrate that the synergy between RBP and CFBFA not only enhances the mechanical properties of the earthwork subgrade backfill but also contributes to a more sustainable construction practice,” Liu stated.
The study meticulously examined various ratios of RBP and CFBFA mixed with coarse-grained soil, revealing that an optimal combination of 8 parts RBP, 32 parts CFBFA, and 60 parts coarse-grained soil results in remarkable mechanical strength. The 28-day unconfined compressive strength reached 5.3 MPa, surpassing standard requirements and indicating that this composite material can withstand significant loads. Additionally, the California Bearing Ratio (CBR) value achieved an impressive 41.9%, showcasing its suitability for use in subgrade applications.
The research also delved into the microstructure of the material, employing advanced techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TG-dTG). The findings revealed that the hydration products primarily consist of C-S-H gel, ettringite, and calcite, which work together to form a robust honeycomb structure that enhances the material’s strength. “The interconnection of these hydration products is critical; it not only fortifies the structure but also improves its durability against environmental factors,” Liu explained.
Beyond structural benefits, this innovative material demonstrates effective cementation and solidification properties for heavy metals, achieving leaching concentrations compliant with Class III water standards as per the Chinese standard GB/T 14848–2017. This aspect is particularly vital as it addresses the growing need for environmentally responsible construction materials that minimize pollution and waste.
The implications of Liu’s research extend far beyond academic interest; they present a viable commercial pathway for construction companies looking to reduce their environmental footprint while maintaining high-performance standards. As the industry increasingly pivots towards sustainability, incorporating such innovative materials could lead to significant cost savings and improved project outcomes.
Published in the journal “Case Studies in Construction Materials,” this research not only contributes to the academic discourse but also serves as a beacon of innovation for the construction sector. The potential for large-scale application of RBP-CFBFA-based materials in earthwork subgrade backfill could reshape future developments, encouraging a shift towards more sustainable practices within the industry.
For further insights into this pioneering work, you can explore Liu’s affiliation at College of Materials Science and Engineering, Xi’an University of Architecture and Technology.
