Utilizing Ground Granulated Blast Furnace Slag during Carbon Sequestration in Concrete

Carbon-sequestered concrete (CSC) and green binders such as ground granulated blast furnace slag (GGBFS) have emerged as promising solutions for reducing the environmental impact of concrete. With the aim of optimizing its carbon capture capacity, the authors attempted to evaluate and enhance the carbon sequestration of GGBFS-added concrete types using cutting-edge CO2 mixing and CO2 curing facilities. Micromechanical tests were performed to determine the impact of CO2 sequestration on the microstructure, strength, and porosity of concrete prepared using this novel binder, which replaced 50% of the conventional cement. Its use demonstrated an encouraging CO2 uptake of up to 20% and improved compressive strength on account of thermodynamically stable calcite polymorph formation, resulting in microstructural densification. Additionally, it could be observed that the CO2 mixing process was uniform, with a conversion rate of 63.41%, whereas CO2 curing was a surface-controlling phenomenon with 96.18% conversion. © 2024 American Society of Civil Engineers.