Concrete, a mixture composed of a cementation agent, mineral aggregates, and water has the potential to serve as a gigaton-scale sink for carbon dioxide (CO₂). This could make concrete the world’s largest CO₂ utilization opportunity. CarbonBuilt’s Reversa^TM process, developed at UCLA’s Institute for Carbon Management exploits simple acid-base chemistry to mineralize CO₂-dilute flue gas emissions into mineral carbonate-based cementation agents at ambient pressure, at flue gas temperatures, and without a need for carbon capture. The approach leverages innovations in the use of portlandite (Ca(OH)₂: calcium hydroxide, or slaked lime) which carbonates readily, and produces limestone (CaCO₃: calcium carbonate) – a potent cementation agent – upon its carbonation. Within the scope of a project sponsored by the US Department of Energy’s Office of Fossil Energy, the Reversa technology was upscaled and demonstrated using a modularized pilot-plant at the Integrated Test Center (Gillette, WY) and National Carbon Capture Center (Wilsonville, AL) using coal- (~12 vol. % CO₂) and natural gas (~4 vol. % CO₂) flue gas streams. The field demonstration led to the production of over 15,000 concrete masonry units (CMUs, also known as concrete blocks) and achieved: (1) a CO₂ utilization efficiency in excess of 75%, and (2) greater than 250 kg of CO₂ utilization per production run. Importantly, based on rigorous 3^rd-party validation, the CMUs produced were confirmed to be compliant with all relevant industry specifications (ASTM C90). The success of this demonstration suggests that the pioneering Reversa technology is ready for commercialization.