Sustainable cementitious materials for building and sorption applications
"Ordinary Portland Cement (OPC) is the most widely used cement material, but it contributes over 8% of the global CO2 emission and the process is energy intensive. Moreover, OPC faces durability challenges, particularly in aggressive environments. Hence, there is rapidly increasing interest in sustainable alternative cements with lower carbon footprint, lower energy consumption, and those that offer superior properties that are beneficial for specific applications. Two sustainable cementitious materials that are frequently researched as an alternative to OPC are calcium sulfoaluminate (CSA) cement and alkali-activated materials (AAMs). CSA cement lowers CO2 emission by over 40% compared to OPC, and it is advantageous due to desirable properties including shrinkage compensation, rapid strength development, and fast setting. However, unanswered questions regarding the early-age and mature-age properties, including rheological properties, hydration kinetics, phase development, durability, and long-term behavior, as well as high cost of the material have limited CSA application in general construction purposes. AAMs contribute little or no CO2 emission, while enabling unique structural and transport properties, including metal sorption capabilities. However, they are also not generally accepted in the industry due to unanswered questions, especially as it patterns the impact of the variability of precursor aluminosilicate materials (e.g., fly ash composition) on the long-term performance of the derived cementitious material. Therefore, the overall objective of this research work is to investigate the aforementioned two sustainable alternative cementitious materials with a view to increasing our understanding of their early-age properties and composition-property relationships"--Abstract, p. iv
Missouri University of Science and Technology
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