# Marble and Glass Waste Powder in Cement Mortar
## 1 Introduction  
Concrete stands as one of the most extensively consumed building materials worldwide, with global production exceeding 10 billion tons annually [1]. Mortar, a crucial binding agent in masonry construction, plays a fundamental role in ensuring structural integrity. Typically composed of cement, fine aggregates, and water, mortar benefits significantly from the superior performance of Portland cement. However, the environmental footprint of Portland cement production is a growing concern. The cement industry accounts for approximately 8% of global CO\({}_{2}\) emissions, with an estimated 4.1 billion metric tons of cement produced annually, consuming vast amounts of energy and non-renewable resources [2]. As infrastructure development accelerates, particularly in emerging economies, the demand for cement is expected to rise, exacerbating environmental challenges associated with its production [3, 4, 5].  
The extraction and processing of raw materials for cement manufacturing contribute to resource depletion, while the carbon-intensive clinkerization process further amplifies greenhouse gas emissions. Given the urgent need for sustainable solutions, researchers are actively exploring alternative materials to partially replace cement without compromising performance. Industrial by-products and solid wastes have gained prominence as viable supplementary cementitious materials (SCMs), offering the dual benefits of waste valorization and environmental impact mitigation [6; 7].  
Among these waste materials, marble and glass waste have emerged as promising candidates for sustainable construction practices [8; 9]. Utilizing waste as a substitute for clinker offers significant benefits, as it not only conserves energy and reduces CO\({}_{2}\) emissions but also enhances concrete properties by increasing its compactness and altering its microstructure [10]. The global marble industry produces millions of tons of waste annually, with an estimated 30-40% of extracted marble ending up as unusable scrap [11]. Improper disposal of marble waste leads to soil degradation, water contamination, and dust-related health hazards [10]. Similarly, glass waste constitutes a major fraction of municipal solid waste, with over 130 million tons generated worldwide each year. Despite existing recycling efforts, only about 20% of glass waste is effectively reused, leaving vast quantities to accumulate in landfills [12]. Recycling glass can reduce energy consumption by up to 27% and lower CO\({}_{2}\) emissions by 37%, underscoring its significance in sustainable construction [13].  
Marble waste, rich in calcium carbonate, serves as an effective filler in cementitious systems, improving packing density and reducing porosity [14]. Conversely, glass waste, primarily composed of silica, actively contributes to pozzolanic reactions, promoting calcium silicate hydrate (C-S-H) formation--a key factor in cement matrix strengthening. The complementary properties of these materials create a synergistic effect, enhancing both mechanical performance and durability in mortar applications [15].  
Given these advantages, the utilization of marble and glass waste as SCMs aligns with global sustainability goals, addressing resource scarcity, waste management challenges, and environmental concerns. This study aims to make a significant scientific contribution by systematically investigating the feasibility of partially replacing cement with marble and glass waste powder (MGWP) in mortar. Through a comprehensive analysis of its effects on fresh, mechanical, durability, and microstructural properties, this research seeks to establish a robust understanding of MGWP's role in sustainable construction. By bridging the gap between material science and practical application, this study contributes to the advancement of eco-friendly cementitious materials and paves the way for more resilient and environmentally responsible infrastructure development.