Use of Marble Dust and Waste Glass in Production of Low-Carbon and Sustainable Cement-Based Composites

This study introduces and investigates a novel phase-specific waste utilization strategy for cement-based materials, aiming to concurrently enhance engineering performance and environmental efficiency. Marble dust (MD) was strategically employed as a partial cement replacement in paste systems, while waste glass (WG) served as a natural sand replacement in mortar. Initial findings indicated a reduction in workability for both MD- and WG-incorporated mixtures, with respective declines reaching up to 48.6% and 44.4%. Early-age compressive strength in MD-added mixtures decreased by up to 9.2%, primarily attributed to dilution effects, while WG-containing mixtures exhibited only minor reductions in early strength. Crucially, significant strength recovery was observed at later ages (>28 days). Compressive strengths ultimately increased by up to 3.8% with MD and 5.1% with WG compared to control mixtures, while flexural strengths saw improvements of 6.8% for MD and a notable 13.8% for WG mixtures. Further analysis revealed improved pore refinement at later ages (>28 days). Porosity decreased substantially, by up to 30.1% for MD-containing mixtures and 22.4% for WG-containing mixtures. Similarly, water absorption was reduced by up to 29.5% for MD and 21.8% for WG, attributing these enhancements to MD’s filler and nucleation effects and WG’s pozzolanic reactivity. From an environmental perspective, MD incorporation led to a significant reduction in CO 2 emissions, up to 10.87%. Conversely, WG generally caused minor increases (up to 0.59%), though a 10% replacement level achieved a 1.43% reduction. These results underscore that cement replacement with MD offers superior environmental benefits compared to aggregate replacement. The study highlights the successful balancing of mechanical properties with environmental sustainability through this phase-specific approach, emphasizing the critical influence of transportation distance on the overall carbon footprint.