Low CO2 design approach of reinforced concrete structures for the targeted CO2 reduction

In this study, the low CO2 design process of reinforced concrete (RC) structures considering the targeted CO2 reduction was presented. The considered system boundary for each processing was presented in the ISO 13315-2. The domestic life cycle inventory database (LCI DB) was used for CO2 assessment of concrete structures. Based on the design process presented in this study, three case studies on the life cycle CO2 assessment of RC shear wall-frame structure were conducted. As the compressive strength of the column was increased from 24 to 40 MPa, the amount of CO2 emissions was increased by about 14% and the targeted CO2 reduction of 20% is not met. As substitution level of ground-granulated blast-furnace slag (GGBS) is 25%, the amount of CO2 emissions and CO2 uptake by concrete carbonation was decreased. The amount of CO2 emissions of the column and total member was decreased by 26 and 22%, respectively, compared to that of OPC. Therefore, substituting GGBS will be more effective to meet the targeted CO2 reduction ratio, rather than increasing the compressive strength of concrete.