# Carbon Emission Analysis of RC Core Wall-Steel Frame Structures
## 2 Materials and Methods
### Carbon Emission Analysis  
The total carbon emission of the life cycle \(C_{\text{tot}}\) in this work is calculated by subtracting the reduction in carbon emissions in the waste recycling stage from the carbon emissions generated during the materialization stage, including building material production, transportation, and construction, as follows:  
\[C_{\text{tot}}=C_{\text{prod}}+C_{\text{trans}}+C_{\text{cons}}-C_{\text{rec}} \tag{1}\]  
where \(C_{\text{prod}}\), \(C_{\text{trans}}\), \(C_{\text{cons}}\), and \(C_{\text{rec}}\) denote the carbon emissions corresponding to the carbon emissions of the building material production stage, the transportation stage, the construction stage, and the waste recycling stage, respectively. Inventory analysis is primarily utilized to calculate carbon emissions during the building material production stage. Consequently, we have:  
\[C_{\text{prod}}=\sum_{i=1}^{n}M_{i}F_{i} \tag{2}\]  
where \(M_{i}\) is the quality of the material \(i\) (t), \(F_{i}\) is the CEF for the material \(i\) (kgCO\({}_{2}\)e/t), and \(n\) is the number of types of materials. In the construction of super high-rise buildings, various building materials are utilized. The carbon emissions for the main building materials are calculated in this work. CEFs for the involved building materials are shown in Table 1 in Appendix A. For the transportation stage, the primary consideration is the carbon emissions generated during the transportation of building materials from the production plant to the construction site. This includes both the direct carbon emissions from the transportation process and the carbon emissions from the production of the consumed energy. The carbon emissions are mainly positively correlated with the distance between the production site and the construction site, the weight of the transported building materials, and thetype of transportation used. Therefore, the carbon emissions during the building material transportation stage \(C_{\text{trans}}\) can be derived as:  
\[C_{\text{trans}}=\sum_{i=1}^{n}M_{i}D_{i}T_{i} \tag{3}\]  
where \(D_{i}\) is the average transportation distance for the material \(i\) (km), and \(T_{i}\) is the CEF per unit weight per unit distance for the transportation method of the material \(i\) (kgCO\({}_{2}\)e/(t\(\cdot\)km)). The CEFs listed in [49] are utilized for the calculation of carbon emissions during the transportation stage, as shown in Table 12 in Appendix A. The carbon emissions during the construction stage consist of emissions from the energy consumption in construction process \(C_{\text{cons, e}}\) and emissions from formwork \(C_{\text{cons, }t}\), as follows:  
\[C_{\text{cons}}=C_{\text{cons, e}}+C_{\text{cons, f}} \tag{4}\]  
The estimation method proposed in [53] is utilized to calculate the carbon emissions for the energy consumption during the construction process \(C_{\text{cons, e}}\), as follows:  
\[C_{\text{cons, e}}=(x+1.99)\cdot S \tag{5}\]  
where \(x\) represents the number of building floors, and \(S\) denotes the total building area. In addition, the carbon emissions from formwork include emissions from material production, transportation, turnover, and recycling. Consequently, we have:  
\[C_{\text{cons, f}}=\sum_{i=1}^{n}\bigg{|}\frac{M_{t, i}}{\varphi_{i}}\bigg{|}\cdot[F_{t, i}(1-R_{i})+T_{t, i}\cdot D_{t, i}] \tag{6}\]  
where \(M_{t, i}\) is the quality of the \(i\)th type of formwork (t), \(\varphi_{i}\) is the turnover times for formwork type \(i\); \(F_{t, i}\) is the CEF for the formwork type \(i\) (kgCO\({}_{2}\)e/t); \(T_{t, i}\) is the CEF for the transportation of the formwork type \(i\) per unit weight per unit distance (kgCO\({}_{2}\)e/(t\(\cdot\)km)); \(D_{t, i}\) is the average transportation distance for the formwork type \(i\) (km); \(R_{i}\) is the recycling and reuse rate for the formwork type \(i\); and \(n\) is the number of types of formwork. The CEFs of different formwork types listed in [49] are applied as presented in Table 13 in Appendix A.