Research On Energy Consumption And Carbon Dioxide Emissions Of Concrete Structures

Since the 21st century,the global warming problem is getting worse.Countries around the world have taken positive measures to deal with the challenges posed by climate change.Due to the characteristics such as high energy consumption and intensive carbon emissions,the construction industry has become one of the most urgent and potential industries to achieve energy conservation and emission reduction.Concrete is one of the main materials of building structures due to its comprehensive advantages in strength,durability,economy,etc.However,the production of concrete raw materials is accompanied by high energy consumption and high emissions.Especially in the production of cement,a large amount of carbon dioxide will be released,which undoubtedly accelerates the global warming process.In the increasingly severe situation of global warming,how to take effective measures to achieve energy saving and emission reduction in the production of building materials has become one of the major issues that need to be resolved.Therefore,it is necessary to conduct in-depth research on the energy consumption and carbon emission characteristics of concrete structures and the corresponding energy-saving and emission-reduction measures.The main contents and conclusions of this article are as follows:(1)The life cycle of the concrete structure is divided into five stages:production,transportation,construction,operation and demolition and waste.The basic statistical methods are compared for energy and carbon emissions,the calculation boundaries of buildings are delineated,and the calculation models for energy consumption and carbon emissions of concrete structures are established.(2)The relevant data of energy and building materials production are collected.The unit energy consumption and carbon emission factors of steel,cement and concrete were analyzed,respectively.A list database reflecting the current status of the building materials production industry is reconstructed.(3)Taking China’s concrete structure as the research object,the carbon emissions of the entire industry life cycle are calculated and analyzed.The results show that the carbon emissions at production stage are second only to operation stage of the concrete structures.A reasonable macro emission reduction strategy is proposed for the cement industry,and the impact of the strategy on the carbon emission development trend of the cement industry is quantitatively evaluated.It is found that three strategies have a positive effect on the carbon emission reduction,and the earlier they are implemented,the greater effect will be achieved.(4)Taking concrete structure as an example,according to the building energy consumption,carbon emission calculation model and the inventory database for building materials,this article calculates the proportion of energy consumption and carbon emissions in each stage,and determines the necessity of energy saving and emission reduction in the production stage of building materials.Further more,the effects of three factors,i.e.,concrete strength,mineral admixture and water reducer,on building energy consumption and carbon emissions were evaluated as well.The results show that the influencing factors of energy saving and emission reduction are ranked as follows:increasing the amount of mineral admixtures,using water reducing agents with high water reducing rate,and improving the strength of concrete.