14th International Congress on Advances in Civil Engineering (ACE2020-21), İstanbul, Turkey, 6 - 08 September 2021, pp.74-80
Production of Portland cement requires 3% of global energy consumption and it is also responsible for 8% of total carbon emissions in the world. Global concrete demand is increasing day by day and it has to be met by sustainable alternatives. MgO cement can be used in concrete instead of Portland cement which poses serious environmental problems in the world because MgO powder can be carbonated to gain strength and consume CO2 during concrete production, which can mean negative carbon emission. Therefore, 4 Portland cement paste groups incorporating 0%, 10%, 50%, and 100% MgO were designed and subjected to carbonation at 20%±1% CO2 concentration for 3, 7, 14, and 28 days. Microstructural investigations and compression tests were conducted at every stage of production and curing. Microstructural analyses showed that carbon dioxide curing caused a reduction in the amount of hydroxide compounds, calcium hydroxide, and magnesium hydroxide, in the paste samples and caused an increase in the amount of carbonated compounds in the paste resulting in prominent compressive strength development. The strength development of the groups incorporating 100% MgO was reasonable after carbonation but only the ultimate strength of hybrid groups was close to that of 100% Portland cement group.