Advancing Circularity in Stone Slurry Waste: Opportunities for Reuse as a Sustainable Filler in Cement-Based Materials

Natural stones have served as essential building elements since ancient eras, maintaining their relevance in contemporary urban development and high-rise structures. Over recent years, the dimension stone industry generates approximately 63.5 million tons of slurry waste annually, representing 20% of processed material and posing significant environmental challenges such as land degradation and water contamination. This review synthesizes global production data, physical-chemical characterizations, and reuse pathways for stone slurry, focusing on its valorization as a sustainable filler in cement-based materials. Key findings include: carbonate slurries (CS) exhibit high purity (>95% CaCO3) and fine particle sizes (d50 ~10–25 μm), enabling 10–15% cement replacement or 20–40% fine aggregate substitution to enhance compressive strength (up to 12% increase) and durability via microstructural densification. Silicate slurries (SS) offer similar benefits but require contaminant management (e.g., heavy metals < 10 ppm). Advanced particle-packing mix designs, such as the cyclic method for low-cement concrete (LCC) and a novel approach for high-strength concrete (HSC), minimize cement content while achieving targets like 31.6 MPa strength, reducing CO2 emissions. In conclusion, reclassifying slurry as a co-product promotes circularity; future efforts should prioritize standardization, contaminant treatments, and lifecycle assessments to integrate high-volume reuse in construction, fostering a low carbon built environment.