In the quest for sustainable construction materials, researchers have turned their attention to an unlikely candidate: coal gangue. This industrial byproduct, often discarded as waste, could soon find new life as a supplementary cementitious material (SCM), thanks to innovative research led by Shiyu Sui from the School of Civil Engineering at Qingdao University of Technology in China.
Coal gangue, primarily composed of clay minerals, has long been overlooked due to its varying grades and low kaolinite content. However, Sui and her team have discovered that with the right activation treatment, even low-activity coal gangue can be transformed into a valuable resource. “Through high-temperature activation, we can unlock the potential of coal gangue, making it a viable substitute for cement clinker,” Sui explains.
The team’s study, published in the journal Buildings (which translates to “大楼” in Chinese), investigated the impact of iron-rich coal gangue on the mechanical properties and microstructure of cement-based materials. By replacing cement clinker with activated coal gangue at proportions of 10%, 15%, and 20%, and mixing it with limestone powder, they created a new cementitious material system.
The results were promising. Compressive strength and microhardness tests revealed that a well-balanced addition of coal gangue could enhance both the mechanical properties and microstructure of the systems. Electrochemical impedance spectroscopy (EIS) and quantitative X-ray diffraction (XRD) analysis further confirmed the positive influence of hydration products and microstructural changes on system performance.
This research offers a scalable, sustainable, and low-carbon alternative for the construction industry, aligning with circular economy principles. As traditional SCMs like fly ash and ground granulated blast-furnace slag become increasingly unreliable, coal gangue presents a vast and underutilized resource.
The commercial implications for the energy sector are significant. By valorizing coal gangue, power plants and mining operations can reduce waste disposal costs and generate additional revenue streams. Moreover, the construction industry stands to benefit from a more sustainable and cost-effective building material.
Sui’s research not only sheds light on the potential of coal gangue but also paves the way for future developments in the field. As the construction industry continues to seek sustainable solutions, the valorization of industrial waste streams like coal gangue could become a key strategy in reducing carbon footprints and promoting a circular economy.
In the words of Shiyu Sui, “Our findings demonstrate that through appropriate activation treatments, coal gangue can be utilized as an effective SCM. This approach offers a scalable, sustainable, and low-carbon alternative for the construction industry, aligning with circular economy principles.”