# Study on the Carbon Emissions in the Whole Construction Process of Prefabricated Floor Slab
## 6 Conclusions  
Based on the LCA framework of the whole PFS construction process, the concept of the evaluation system of carbon emissions were expanded, the calculation scope was divided, and the calculation formula was established. Combined with a case study of the whole construction process of HB2022-1 prestressed laminated slab, the carbon emissions in each stage with the same engineering unit volume were analyzed, and the carbon emissions of PFS and cast-in-place floor slab were compared. The following conclusions are drawn:  
(1) The production stage has the largest carbon emissions in the whole PFS construction process. According to the empirical research in this paper, the carbon emissions in the production stage account for 97.5% of the total carbon emissions of the whole construction process, whereas the transportation stage and construction stage account for less than 3%. Therefore, measures to reduce PFS carbon emissions should first consider the production stage. (2) Emission reduction measures should be considered from raw materials. The carbon emissions of raw materials account for 85.4% of the whole production stage and nearly 83% of the whole construction process. The two types of materials that produce the most emissions are rebar and concrete. Therefore, the optimization of raw materials to reduce carbon emissions in the production stage should be considered; materials with low carbon emission factors should be used to ensure floor components meet mechanics and thermodynamics requirements. It is also necessary to strengthen the management of the production stage to reduce material waste in production. (3) Increasing the use of PFS will help reduce carbon emissions. The carbon emitted by the whole PFS construction process is 578.746 kg/m\({}^{3}\), which is about 35% less than that of cast-in-place floor slabs, which is 890.04 kg/m\({}^{3}\). Therefore, under the strengthened scientific management, the use of PFS in buildings can significantly reduce the total carbon emissions and promote the development of low-carbon buildings. It should be noted that the building construction engineering includes three main parts: foundation engineering, structural engineering, and decoration engineering [29; 30; 31], which together constitute the carbon emission system of the whole building. This paper only studies the carbon emission system of PFS in structural engineering. At the same time, cement is a main component of carbon emission materials, and reducing cement consumption can reduce the carbon emission of buildings in essence. In the future, optimizing the whole architectural design system based on the application of new renewable materials and nano materials is a major research topic to reduce the carbon emission of the architectural system [25; 32; 33]. All authors contributed substantially to this study. Individual contributions are: formal analysis, A.K. ; writing-original draft, H.K. ; investigation, S.H. ; writing-review and editing, N.L. and W.W. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The authors declare no conflict of interest.