Integrated model for assessing the cost and CO2 emission (IMACC) for sustainable structural design in ready-mix concrete

Cost has traditionally been considered the most important factor in the decision-making process. Recently, along with the consistent interest in environmental problems, environmental impact has also become a key factor. Accordingly, there is a need to develop a method that simultaneously reflects the cost and environmental impact in the decision-making process. This study proposed an integrated model for assessing the cost and CO2 emission (IMACC) at the same time. IMACC is a model that assesses the cost and CO2 emission of the various structural-design alternatives proposed in the structural-design process. To develop the IMACC, a standard on assessing the cost and CO2 emission generated in the construction stage was proposed, along with the CO2 emission factors in the structural materials, based on such materials' strengths. Moreover, using the economic and environmental scores that signify the cost and CO2 emission reduction ratios, respectively, a method of selecting the best design alternative was proposed. To verify the applicability of IMACC, practical application was carried out. Structural designs were assessed, each of which used 21, 24, 27, and 30 MPa ready-mix concrete (RMC). The use of IMACC makes it easy to verify what the best design is. Results show the one that used 27 MPa RMC was the best design. Therefore, the proposed IMACC can be used as a tool for supporting the decision-making process in selecting the best design alternative.

► IMACC supports the decision-making process in selecting the most sustainable structural design.
► IMACC assesses both the cost and CO2 emission of structural design.
► Economic and environmental scores are used in selecting the most sustainable design.
► Two scores signify the cost and CO2 emission reduction ratios, respectively.
► CO2 emission factors of RMC by strength are proposed for assessing CO2 emission.