Mechanical, Environmental and Economic Feasibility Analysis of Sodium Carbonate Activated Blast Furnace Slag

Due to the large amount of cement that is used globally, the production of cement has a large impact on the environment. The area of Alkali Activated Materials (AAMs) has become a promising research avenue in the search for a low-carbon emission alternative to Portland cement based concrete. There has been a lot of research into using sodium hydroxide, sodium silicate and potassium hydroxide activation of industrial by-products like blast furnace slag and fly ash. However, environmental impact research in AAMs has shown large impacts from the activators used. This study examines initial setting time, compressive strength, environmental impact, and cost of sodium carbonate activated blast furnace slag as a function of their ingredients. This is done via a statistically designed mixture experiment to analyze mechanical properties and a comparative LCA using SimaPro to determine environmental impacts. The study concludes that sodium carbonate activated blast furnace slag (SCABFS) materials can be designed to meet ASTM standards for concrete initial setting time and compressive strength. Overall environmental impact of Portland cement based binder as measured by ReCiPe ecopoints is reduced by 33% in SCABFS binder if slag is considered a waste product of steel production. If slag is not considered to be a waste product of steel production, the SCABFS binder exhibited significantly higher overall environmental impacts than Portland cement binder.