Life cycle CO2 assessment of concrete by compressive strength on construction site in Korea

As research on the reduction in the life cycle carbon dioxide (LCCO2) emissions of buildings has become increasingly important, the development of technologies that can quantitatively assess the LCCO2 emissions of a building at the level of the construction materials is essential. In addition, concrete of various compositions, such as high-performance concrete mixed with fly ash and blast furnace slag and eco-concrete, has become readily available and thus, a quantitative evaluation of CO2 basic units for these new materials is needed. However, basic units for various types of concrete are not provided by the National Life Cycle Inventory Database (LCI DB) in Korea. Therefore, thorough research on these materials has become an important priority.In this study, a method to assess LCCO2 emissions using the compressive strength of concrete is proposed. Specifically, the compressive strengths of various mixes of concrete that are employed at construction sites in Korea were utilized to evaluate CO2 emissions. Comparisons according to the characteristics of each mixture were also made.Approximately 560 concrete mix designs used at construction sites were first classified according to the compressive strength, admixture, and season. The concrete CO2 emissions assessment process was carried out for the concrete raw materials production stage, the concrete raw materials transportation stage, and the concrete production stage; quantitative assessment methods are proposed for the CO2 emissions at each stage. Based on the proposed assessment methods, an evaluation of the concrete CO2 emissions was conducted and the obtained values were analyzed.