| Abstrakt: |
CO2sequestration by mineral carbonation in calcium- and magnesium-rich cementitious materials, such as cement-based concrete, during production is a beneficial utilization of CO2. This way, a greenhouse gas is used as an admixture in concrete production, giving double-fold benefits. The present research investigates the properties of concrete produced with CO2as an admixture. A novel two-step CO2mineralization into concrete process was adopted in the present research; 0.1%, 0.2% and 0.3% CO2were mineralized in three batches of concrete and compared with normal concrete, in which no CO2was mineralized. Slump, compressive strength, flexural strength, changes in compressive strength, weight and chloride ions content under chloride exposure conditions were determined. In addition, scanning electron microscopy was studied to determine the microstructure of concrete. The finding of the present research is quite promising for the use of CO2by a small percentage of cement used in concrete. At 0.2% CO2mineralization by the weight of cement used, 6.3% and 3.28% greater compressive and flexural strength, respectively, were noticed at 28 days of testing. Furthermore, a 1.42% higher compressive strength, 0.1% lower rise in weight, and 0.03% lower chloride content were found in CO2mineralized concrete at 180 days of chloride exposure condition than normal concrete. Hence, this research shows the beneficial use of CO2as an admixture in concrete is a viable practice for improving concrete properties and reducing CO2emission into the atmosphere. |
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