The project addresses and discusses environmentally effective ways to deal with greenhouse gas (GHG), a harmful byproduct of cement production. Over 90% of GHG emissions are triggered by the production of conventional cement: the latter involves carbon dioxide (CO2) gas emissions, which can be thought of as the cornerstone problem. To meet the regulatory mandate of California's cement industry, GHG emissions should be net-zero. This requires CO2 uptake by the mechanism of Direct Air Capture (DAC). Due to its effective CO2 uptake, carbonation is known to have good potential to be the DAC mechanism: concrete that is removed at end-of-life (EoL) can be crushed and spread to facilitate carbonation. This project studies how the CO2 uptake can be most successfully carried out. It assesses the current state of technology and develops a pathway to utilize end-of-life concrete as a Direct Air Capture method. The project uses three objectives in the study: (1) A systematic review of the literature to compile parameters to drive carbonation of concrete, (2) A meta-analysis of data to derive initial engineering of EoL concrete as a DAC method, (3) A preliminary experimental investigation and modeling of CO2 uptake. Through these three objectives, the study considers the EoL concrete processing to support carbonation, and includes meta-analyses of reported data for parameters that will drive carbonation. In addition, the project will provide a strong base for the future research that will be required to demonstrate this technology and encourage adoption in industry. Finally, This work leverages the Principal Investigator's expertise in decarbonizing cement and concrete, lifecycle and EoL impacts of concrete infrastructure, and engineering composites as carbon sinks.
