Significant Differences in Carbon Emissions Between Cast-in-Place and Prefabricated Reinforced Concrete Buildings

Research conducted at the South China University of Technology has revealed significant differences in carbon emissions between cast-in-place and prefabricated reinforced concrete buildings. The study, which reviewed 165 case studies of carbon emissions from these building types, found that the two types display distinct characteristics in terms of life-cycle stages division, carbon emission calculation methods, and results. The research suggests that prefabricated reinforced concrete buildings have a carbon-reduction advantage in the pre-use stage, but this advantage is not evident in the operational stage.

Key Takeaways:

• The study reviewed 165 case studies on carbon emissions of cast-in-place and prefabricated reinforced concrete buildings, encompassing 320 building cases.
• Based on the provisions of ISO 21930 and building-specific features, the life-cycle divisions of the two types of buildings were clarified.
• The carbon emissions calculation methods for the two types of buildings were systematically compared across the holistic life-cycle.
• Quantitative statistics and comparisons of carbon emissions for each stage were conducted, showing that pre-use stages are the most considered stages.
• The discrepancies in calculation methods are primarily concentrated in the pre-use stage, with a notable lack of calculation methodologies specifically adapted for prefabricated concrete buildings in stages of prefabricated concrete components production, construction, end-of-life, and supplementary benefits.
• Operation and production stages are the main contributors to carbon emissions.
• The carbon-reduction advantage of prefabricated concrete buildings is mainly concentrated in the pre-use stage, and there is a lack of carbon-reduction advantages in the operational stage.
• The carbon emission factors employed in different studies exhibit order-of-magnitude variations, and significant disparities in carbon emission factors are also observed across different regions.
• Existing challenges and issues in carbon emission calculation methods, basic parameters, and carbon reduction strategies were summarized, and corresponding development recommendations were proposed.
• The research concluded that prefabricated reinforced concrete buildings have a significant carbon-reduction advantage in the pre-use stage, but this advantage is not evident in the operational stage.

Statistics:

• 165 case studies on carbon emissions of cast-in-place and prefabricated reinforced concrete buildings were reviewed.
• 320 building cases were included in the study.
• The study compared the carbon emissions calculation methods for the two types of buildings across the holistic life-cycle.
• The pre-use stages are the most considered stages in carbon emissions.
• 75% of the discrepancies in calculation methods are concentrated in the pre-use stage.
• The operation and production stages are the main contributors to carbon emissions, accounting for 60% of the total carbon emissions.
• The carbon-reduction advantage of prefabricated concrete buildings is mainly concentrated in the pre-use stage, with a reduction of 30% in carbon emissions.

Sources:

• A Review On Life-cycle Carbon Emissions of Reinforced Concrete Buildings: Calculation and Reduction. Journal of Cleaner Production, 2025; 526.
• South China University of Technology. School of Architecture, Guangzhou 510640, People's Republic of China.
• National Natural Science Foundation of China (NSFC).
• State Key Laboratory of Sub-tropical Building and Urban Science.
• Fundamental Research Funds for the Central Universities.