In the quest for sustainable construction materials, a team of researchers led by Yue Wang from Shenzhen University has made a significant breakthrough. Their study, published in the journal *Cleaner Materials* (translated as “Cleaner Materials”), explores the potential of using calcined sand-washing slurry (SWS) as a green alternative to traditional metakaolin in limestone-calcined clay cement (LC3). This innovation could have profound implications for the energy sector, particularly in reducing carbon emissions and improving the efficiency of cement production.
The research team, based at the College of Civil and Transportation Engineering and the Shenzhen Key Laboratory for Low-carbon Construction Material and Technology, investigated the effects of SWS and polycarboxylate superplasticizer (PCE) on hydration, microstructure, and strength development. Using advanced techniques such as isothermal calorimetry, XRD, SEM-EDS, and TG-FTIR, they found that SWS contains reactive amorphous aluminosilicates that promote the formation of ettringite (AFt), enhancing early strength in concrete.
One of the most striking findings was that the 750°C-calcined SWS sample (S750) achieved a 28-day compressive strength of 46.6 MPa, just 3.5% lower than traditional LC3. This suggests that SWS could be a viable and sustainable alternative to metakaolin, which is often used in LC3 production. “The results are promising,” said Yue Wang, the lead author of the study. “We found that SWS not only performs well in terms of strength but also offers significant environmental benefits.”
The study also revealed that PCE significantly improved the flowability of the mixture, with the S750-1 sample achieving a flow of 175 mm. This enhancement did not compromise early strength and even accelerated the generation of AFt, leading to a denser matrix. Notably, the 700°C-calcined SWS sample (S700) exhibited comparable strength and hydration behavior to S750, indicating that low-temperature calcination is both feasible and energy-efficient.
From an environmental perspective, the life cycle analysis showed that the CO2 emissions of S700 are reduced by approximately 34.6% compared to traditional calcined gypsum (CG). This reduction is a significant step towards lowering the carbon footprint of the construction industry, which is a major contributor to global emissions.
The implications of this research are far-reaching. As the demand for sustainable construction materials grows, the use of SWS in LC3 production could become a standard practice. This shift could lead to substantial energy savings and reduced greenhouse gas emissions, aligning with global efforts to combat climate change.
Moreover, the findings suggest that low-temperature calcination is a viable option, which could further reduce energy consumption and costs. “This research opens up new possibilities for the construction industry,” said Yue Wang. “By leveraging sustainable materials like SWS, we can create high-performance, low-carbon concrete that meets the demands of modern construction.”
As the industry continues to evolve, the adoption of innovative materials and technologies will be crucial. The study by Yue Wang and his team highlights the potential of SWS as a sustainable alternative to traditional materials, paving the way for a greener and more efficient future in construction. With the publication of this research in *Cleaner Materials*, the scientific community and industry professionals now have a compelling case to explore the use of SWS in their projects, contributing to a more sustainable and environmentally friendly construction sector.