In the quest for sustainable construction materials, researchers have turned an unlikely waste product into a valuable resource. A recent study led by Zoi S. Metaxa of the Hephaestus Laboratory at Democritus University of Thrace has revealed that waste marble slurry can serve as a partial replacement for ordinary Portland cement, offering both environmental and economic benefits. The research, published in the journal *Applied Sciences* (translated as *Applied Sciences*), sheds light on how this innovative approach could reshape the construction industry.
Marble slurry, a byproduct of marble cutting and polishing, has long been a nuisance for manufacturers, often ending up in landfills. However, Metaxa and her team have demonstrated that this waste material can be repurposed to enhance the properties of cement-based materials. “Marble slurry behaves as an inert filler, improving the fresh properties and mechanical performance of cement mixes, particularly at higher water-to-cement ratios,” Metaxa explained. This finding opens up new possibilities for reducing both cement consumption and marble waste disposal.
The study investigated the effects of different water-to-cement (w/c) ratios and varying levels of marble slurry substitution. Cement pastes were prepared with w/c ratios of 0.3, 0.4, and 0.5, and marble slurry was substituted at levels ranging from 0% to 20%. The results showed that incorporating up to 10% marble slurry significantly improved workability and mechanical performance in mixes with higher w/c ratios. “At lower w/c ratios, strength was adversely affected due to insufficient hydration,” Metaxa noted. This suggests that the optimal use of marble slurry depends on the specific conditions of the cement mix.
Electrical resistivity measurements provided further insights into the behavior of the modified cement pastes. Pastes with a w/c ratio of 0.5 and up to 10% slurry replacement exhibited slightly higher resistance to electrical current, indicating improved durability. In contrast, mixes with lower w/c ratios showed only minor reductions in resistivity at 5% and 10% cement substitution. Scanning electron microscopy (SEM) imaging revealed a denser microstructure when marble slurry was incorporated, consistent with a filler effect.
One of the most intriguing findings was that marble slurry accelerates the setting of cement pastes, an effect most evident at lower w/c ratios and higher substitution levels. This could have significant implications for construction projects, where faster setting times can enhance efficiency and reduce costs.
The commercial impacts of this research are substantial. By utilizing waste marble slurry, construction companies can reduce their reliance on cement, a major contributor to carbon emissions. This not only aligns with sustainability goals but also offers a cost-effective solution for managing industrial waste. “This research highlights the potential of waste marble slurry as a valuable resource in the construction industry,” Metaxa said. “It contributes to sustainable construction practices by reducing both cement consumption and marble waste disposal.”
As the construction industry continues to seek innovative ways to minimize its environmental footprint, the findings of this study offer a promising avenue for exploration. By repurposing waste materials and optimizing their use in cement-based materials, researchers and industry professionals can pave the way for a more sustainable future. The research published in *Applied Sciences* serves as a testament to the power of interdisciplinary collaboration and the potential for waste materials to become valuable resources.