4.2.1. Transportation Stage

In order to deduce the amount of fuel consumed by each work type in the transportation stage, the amount of CO2 emissions in the transportation stage was estimated by considering fuel efficiency regarding the number of vehicles used, transportation distance, and each kind of equipment. The transportation equipment count, according to the load sizes of equipment that transported materials to the construction site, was analyzed as shown in Table 4. The results showed that most of the material was reinforced concrete in the case of 20-ton trucks and 6 m<sup>3</sup> concrete-mixer trucks. For 5-ton trucks, most of the material was for tile work. The total amount of CO2 emissions from the transportation stage analysis results was 5.46 kg-CO2/m<sup>2</sup> in as shown Figure 5. The amount of CO2 emissions from reinforced concreted work accounted for 89% of all work types, which was analyzed to display most of the CO2 emission characteristics. The analysis results for the CO2 emission characteristics of other kinds of construction, were analyzed in the order waterproof construction, tile work, and plastering; and the amount of CO2 emissions for each construction type was 0.08 kg-CO2/m2, 0.07 kg-CO2/m2, and 0.06 kg-CO2/m2, respectively. After analyzing 34,500 transportation vehicles used at the construction site for each work type, the amount of CO2 emissions from the 30,422 concrete transportation vehicles used for the reinforced concrete work accounted for around 75% of the amount of CO2 emissions for the entire transportation stage. Therefore, it was found that the load distance between the construction site and the concrete manufacturer (when concrete is collected for reinforced concrete work), and the fuel efficiency of concrete transportation vehicles must be managed in order to reduce the amount of CO2 emissions in the construction process.
