# Assessment of Carbon Emissions at the Logistics and Transportation Stage of Prefabricated Buildings
## 4 The Case Study of Jinan Building Construction Site  
We consider a project in the Jinan area in China as an example. The project included five simply furnished 12-story public rental housing residential buildings with a total construction area of 20,327.1 m\({}^{2}\), all built via prefabricated assembly construction. Building 2 of the project was selected for the carbon emission analysis, with a GFA of 3876.1 m\({}^{2}\). The total steel consumption of the project was 31,003.27 kg, the concrete consumption was 1810.01 m\({}^{3}\), and the wood consumption was 27,802.27 kg. The average transportation distance of building materials was obtained from transportation companies and building material suppliers. Building material transportation vehicles were all heavy-duty diesel trucks, with a rated load capacity of 30 T. According to the Standard for Calculation of Construction Carbon Emissions (GB/T 51366-2019), it can be determined that the carbon emission factor per tonne of building materials transported in the starting logistics phase is 0.078 kgCO\({}_{2e}\)/(t\(\Delta\)km). The carbon emissions of the transportation process of building material logistics are summarized in Table 6 where 1 m\({}^{3}\) C30 concrete weighs approximately 2400 kg. The loading and unloading of prefabricated components mainly relies on gantry cranes and tower cranes, and electricity is the main energy consumed. Since Jinan is in East China, its electricity carbon emission factor is 1.04 kgCO\({}_{2}\)/kWh. The carbon emissions of on-site transportation are shown in Table 7. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Name of Building** & & & & **Average Transportation** & **Carbon Emission Factor** & **Total Carbon** \\
**Material** & & & & **Distance (kg)** & **[kgCO\({}_{2e}\)/(t\(\cdot\)km)]** & **Emissions (kg)** \\ \hline
**Steel** & kg & 310,003.27 & 130.89 & 0.078 & 3164.95 \\
**Concrete C30** & m\({}^{3}\) & 1810.01 & 68.22 & 0.078 & 23,115.25 \\
**Wood** & kg & 27,802.27 & 58.03 & 0.078 & 125.84 \\
**Total** & & & & & 26,406.04 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Carbon emissions from the transportation of major building materials. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Energy** & **Total Energy** & **Unit** & **Carbon Emission Factor** & **Total Carbon** \\
**Consumption** & & & **(kgCO\({}_{2e}\)/units)** & **Emissions (kg)** \\ \hline
**Electricity** & & & & \\
**consumption** & 11,020.89 & kWh & 1.04 & 11,461.73 \\
**(kWh/m\({}^{2}\))** & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: On-site transportation carbon emissions. For the prefabrication rate of the assembled building and the prefabricated component transportation vehicle, the Changan Star 9 compartment transporter was selected. The energy source was 92 gallons of gasoline, and its rated capacity was 630 kg. The total weight of transported prefabricated components for one building was 3271.08 t. Values for the transportation of prefabricated components and carbon emission factors of gasoline vehicles, under different full-load rates (Table 5), were utilized in carbon emission simulations to obtain carbon emission values under different full-load rates, as shown in Table 8. Based on actual engineering experience, the one-way distance of the assembly was taken as 100 km. Figure 1 compares the carbon emission levels of each component of the logistics and transportation stage. In Figure 1, \"a\" represents the transportation of building materials, \"b\" represents the loading and unloading of prefabricated components, and \"c\" represents the off-site transportation of the prefabricated components. The off-site transportation of the prefabricated components was plotted at a full-load rate of 70%. Figure 2 shows the carbon emission calculation of precast transportation under different full-load rates.