Research On Evaluating Methods For Carbon Emissions Of Building Construction On Life Cycle Assessment

Global warming resulting from greenhouse gases emission has been spotlight of global Change attention for years,countries in the world in reducing greenhouse gas emissions contribute their strength.The life cycle of building,from construction,installation,operation to demolition,is not only energy consumed but greenhouse gases eliminated,thus regarded as the major gateway for global warming.Among which,construction is the critical part for evaluating for its intensive and concentrative emission process.The process of construction not only consumes various sources but employed lots of construction machinery and transport equipment,thus released lots of greenhouse gases within a relatively short period.The greenhouse gases released from construction is the crucial part in evaluating the carbon emissions during the life span of building.Construction is the critical part for evaluating for its intensive and concentrative emission process.However,at present,the research on carbon emission of construction activities is not deep.In view of this situation,this paper uses LCA to set up a model of measurement and evaluation of carbon emissions for construction projects.Firstly,based on the whole life cycle theory and the green Construction evaluation frame and construction management technology,this paper defines the target and scope of the greenhouse gas emission accounting of construction activity with the construction unit as the main body;based on the construction unit process,a list analysis of the construction carbon emission accounting is established.And in the above work This paper constructs the mathematical model of carbon emission calculation for construction activity,establishes the framework of carbon emission accounting for construction activities,and takes the student dormitory building of Shenzhen University as a sample,calculates the construction process in detail: earthwork,Foundation Engineering,masonry engineering and reinforced concrete engineering,etc.This paper constructs the model of greenhouse gas emission accounting in construction stage,realizes the quantification of construction discharge,and carries out empirical research,and obtains such conclusions and results as follows:(1)from the analysis of construction process,the construction activities of residential cases,earthwork,concrete engineering,Vertical engineering and reinforcement engineering is the main construction process of construction carbon emission,which accounts for more than 60% of total construction carbon emissions.(2)from the perspective of emission sources,of the four types of carbon emissions from construction activities,the cumulative emissions of materials,electricity and diesel emissions are more than 85%,which are the main sources of carbon emissions,and the carbon emissions from petrol are the smallest in each case.(3)For the case one of the construction machinery and equipment to be working time,concrete materials,rebar materials,masonry materials for the sensitivity analysis,of which,the electrical machinery and equipment caused by carbon emissions for mechanical equipment standby time is more sensitive to shorten standby times,carbon emissions drop significantly.The loss rate of masonry material is sensitive to the carbon emission of the project,the loss rate is reduced,and the carbon emission will be improved obviously.The total carbon emissions of concrete materials and steel materials are large,the loss rate of concrete materials is reduced,the carbon emissions of the project are significantly affected,and there is potential for reducing carbon emissions.The use of steel materials is large,the impact on carbon emissions is more significant,the reduction of carbon emissions also has room for improvement.The results of this paper are of guiding significance to the concrete emission reduction measures such as building selection,material selection and construction scheme design.