Cement production is a major global CO₂ emitter, and gemstone polishing generates large quantities of silicon carbide waste, especially in hubs such as China’s Guangdong province. The waste is non-biodegradable and typically ends up in landfills. Scientists from Wuzhou University and Guangzhou University decided to explore whether this leftover material could be repurposed to improve cement instead of discarding it, says Tech Xplore.
In their study (published in the journal AIP Advances), the researchers added gemstone polishing waste into cement mixtures and tested effects from the molecular to macro scale. They examined how the waste particles interact chemically with calcium ions (essential for cement hardening), how they affect microstructures (porosity, cracks), and how the final mixtures perform in terms of strength, conductivity, and thermal behavior.
What they found surprised them. The silicon carbide dramatically improved thermal conductivity by up to 159% and reduced electrical resistivity by as much as 94%. That suggests a path to “smart” cement, which could be used in building materials to passively manage heat or embed sensors to monitor structural health.
Still, challenges remain. The waste particles have a weak affinity for calcium ions, which complicates the process of integrating them in a way that doesn’t impair cement strength. The researchers intend to optimize the blend ratios, study long-term durability, conduct real-world field tests, and explore applying the same approach to other waste materials.
This approach tackles two environmental problems at once: reducing waste from gemstone processing and decreasing the carbon impact of building materials. With further refinement, gemstone waste might not be just a disposal challenge; it could become a key ingredient in the materials of tomorrow.