Life Cycle Environmental Impact Assessment Of Transportation Infrastructure Based On LCA

At the beginning of the 2020s,the frequent occurrence of large-scale natural disasters in the world has a complex relationship with environmental damage.Human activities,especially the large-scale transportation infrastructure construction activities,have brought a series of negative effects on the natural environment.Therefore,it is necessary to make adequate predictions and assessments of these negative effects.However,at the present stage of high-quality development of transportation industry,how to overcome the difficulty of the lack of methods and models of environmental impact assessment of transportation infrastructure and carry out a comprehensive and effective assessment of environmental emissions from transportation infrastructure construction activities is still the key problem to be solved urgently.In order to response this problem,based on the theory of life cycle assessment（LCA）,the comprehensive indicators and methods were used for EIA-TI model to analyze the environmental emissions of transportation infrastructure.Meanwhile,the life cycle of transportation infrastructure was divided into materialization phase,maintenance phase and demolition phase.Using the highway projects in China as cases study,after carrying out the environmental emission analysis and impact assessment for these three phases,the suggestions for energy saving&emission reduction measures for each phase were provided.Furthermore,the sensitivity factors that affecting the results were revealed,and the sensitivity analysis of the environmental impact assessment results of the transportation infrastructure life cycle was carried out.The research finds that:（a）the materialization phase contributes the most due to its large and complex materials and energy use,with an average contribution of 82.5%to all environmental impact assessment indicators.Among them,steel has the greatest impact on global warming and eutrophication,with the average environmental emissions of 520584 g CO₂eq/m² and 1542 g N eq/m²,respectively.Additionally,asphalt concrete is the largest contributor to acidification and smog,which emissions are respectively 78264 H+mmole eq/m² and 882 g NOx eq/m².（b）The amount of materials used has a decisive contribution to the environmental impact of the materialization phase.Therefore,fine management of the use of materials is required to avoid causing additional environmental emissions,especially of steel and various concrete.Moreover,in the maintenance phase（accounting for 14.81%）,preventive daily maintenance should be added to reduce the heavy repair that causes the main environmental impact in this phase.（c）Transportation distance,energy saving potential ratio,and maintenance energy consumption are the sensitivity factors that affect the results of environmental impact assessment.Nevertheless,the eight categories of environmental impact assessment indicators are mainly sensitive to the energy saving potential ratio,and their sensitivity range is0.14<β<0.5.Additionally,the variations of environmental impact results caused by the three sensitivity factors are all within 5.5%,which indicates that the results of this study are highly effective and reliable.This study contributes to providing the beneficial exploration and the practice for perfecting the transportation infrastructure life cycle environment emissions measurement system.Meanwhile,it is conducive to promoting the improvement of environmental management of transportation engineering.Elsewhere,this study provides scientific basis for relevant departments to formulate appropriate energy saving&emission reduction policies,so as to promote high-quality development of the transportation industry.