To comply with recent international trends and initiatives, and in order to help achieve sustainable development, Korea has established a greenhouse gas (GHG) emission reduction target of 37% (851 million tons) of the business as usual (BAU) rate by 2030. Regarding environmentally-oriented standards such as the IGCC (International Green Construction Code), there are also rising demands for the assessment on CO 2 emissions during the life cycle in accordance with ISO (International Standardization Organization’s Standard) 14040. At present, precast concrete (PC) engineering-related studies primarily cover structural and construction aspects, including improvement of structural performance in the joint, introduction of pre-stressed concrete and development of half PC. In the manufacture of PC, steam curing is mostly used for the early-strength development of concrete. In steam curing, a large amount of CO 2 is produced, causing an environmental problem. Therefore, this study proposes a method to assess CO 2 emissions (including absorption) throughout the PC life cycle by using a life cycle assessment (LCA) method. Using the proposed assessment method, CO 2 emissions during the life cycle of a precast concrete girder (PCG) were assessed. In addition, CO 2 absorption was assessed against a PCG using conventional carbonation and CO 2 absorption-related models. As a result, the CO 2 emissions throughout the life cycle of the PCG were 1365.6 (kg-CO 2 /1 PCG). The CO 2 emissions during the production of raw materials among the CO 2 emissions throughout the life cycle of the PCG were 1390 (kg-CO 2 /1 PCG), accounting for a high portion to total CO 2 emissions (nearly 90%). In contrast, the transportation and manufacture stages were 1% and 10%, respectively, having little effect on total CO 2 emissions. Among the use of the PCG, CO 2 absorption was mostly decided by the CO 2 diffusion coefficient and the amount of CO 2 absorption by cement paste. The CO 2 absorption by carbonation throughout the service life of the PC was about 11% of the total CO 2 emissions, which is about 16% of CO 2 emissions from ordinary Portland cement (OPC) concrete.
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