Life Cycle Assessment Of Carbon Emission Of Buildings

The environmental impact caused by the construction industry has become extremely urgent.The life cycle assessment(LCA)theory is adopted in this paper to analyze the carbon emission of both on-site and off-site concrete buildings.Analysis of a Chinese on-site concrete building case has been conducted based on the input-output hybrid method.Stages from material extraction,manufacture,transportation,construction,operation,maintenance to demolishing are selected as the system boundary and the carbon emission percentages of concrete,steel,glass and etc.are obtained.Targeting the operation stage with the most extensive carbon emission,energy cut advices are provided.In order to avoid the energy shift between stages,the process-based method is applied to analyze the carbon emission of the off-site concrete building.The system boundary contains the material extraction,components fabrication,transportation and the on-site construction stages for better comparison.The off-site construction possesses higher efficiency of material consumption and better management due to its industrialized manufacture.However,the transportation between prefabrication factory to the construction site,the large amount of steel embedded parts as well as the large thickness of the external will significantly influence the carbon emission level of the building.So promoting the prefabrication factory construction,improving the design modularization will help reduce the energy and material consumption as well as the carbon emission.The comprehensive material embodied energy coefficients under Chinese standard are obtained through data collection and calculation.The paper also introduce the participation in the life cycle carbon emission calculation software development and the LCA-BIM integrated model for better application of the LCA theory in the construction industry.