Performance, phase composition, and life cycle assessment of marble waste-infused Portland and alkali-activated cements and mortars: A comparative analysis and perspective

While extensive research has explored the macro-scale effects of marble waste powder (MP) on Portland cement (OPC) mortar and concrete, a significant knowledge gap persists regarding its impact on both the macro- and micro-structural properties of OPC and alkali-activated materials (AAMs). This state-of-the-art review aims to address this gap by providing a comprehensive comparative analysis of MP's influence on the fresh and hardened properties, as well as the phase composition of OPC and AAM pastes and mortars. Additionally, the paper delves into the life cycle assessment and processing costs of OPC-MP and AAMs-MP systems. The limitations of this study and future directions for MP applications in various binding systems are discussed. Generally, replacing OPC with MP decreases mechanical performance and slows the hydration rate due to cement dilution. However, the performance of MP-AAM is primarily influenced by the type and dosage of the alkali activator. MP enhances the performance of AAMs in sodium silicate-activated systems, whereas it negatively affects sodium hydroxide and sodium carbonate-activated systems. In OPC systems, MP primarily acts as a filler material; nevertheless, it contributes to the formation of monocarboaluminate binder. In contrast, in alkali-activated systems, the chemical reaction mechanism of MP predominates over its physical effects. This paper serves as a valuable resource for researchers and practitioners, offering insights into the in-depth reaction mechanisms of MP within both OPC and AAMs systems.