Resource And Environmental Impact Assessment Of Permeable Pavement Based On Life Cycle Method

As a typical sponge city infrastructure,permeable pavement can produce a variety of environmental benefits such as urban rainwater runoff reduction,water quality purification and so on.On the other hand,in the process of material preparation,construction,maintenance and management,permeable pavement has increased resource and energy consumption compared with ordinary pavement.It is necessary to apply the systematic analysis method of life cycle assessment(LCA)to carry out a comprehensive assessment of the resource and environmental benefits of permeable pavement.Based on literature review,this paper summarizes the status and challenges of LCA application to permeable pavement assessment,and proposes corresponding countermeasures.First,the operation and maintenance stages need to be included in the boundary of the assessment system to improve the comprehensiveness of the resource and environmental evaluation of permeable pavement.Second,aiming at the problems in the use stages such as the dynamic changes of permeation effects,it is recommended to introduce hydrological models into the method.Therefore,based on the rainfall characteristics and pavement engineering practice in Beijing,this paper adopts the LCA method,combined with the storm water management model(SWMM)to simulate the environmental benefits of permeable pavement in the use stage,comprehensively analyzes the environmental impact of permeable pavement in the whole life cycle,and compares the difference of environmental impact between permeable pavement and ordinary pavement in the life cycle,as well as the changes with different maintenance methods.The results show that:(1)The life cycle environmental impact of ordinary pavement and permeable pavement mainly comes from the production stage.The input of aggregate and cement in its production stage causes resources,energy consumption and environmental pollutant emission,which are the main factors of life cycle environmental impact.(2)Due to the demand for water permeability,it needs special production technology and higher level condition requirements for production of permeable brick pavement.Therefore,for the same quantity of ordinary bricks and permeable bricks,the latter has a greater environmental impact.In the construction stage,permeable brick pavement will also have more environmental impact due to the special construction technology required by its permeable structure.(3)In the use stage,permeable pavement can produce better environmental benefits due to its water permeability and water purification.The size of environmental benefits will be affected by the maintenance methods,and the type of permeable material will also affect the difference of its best maintenance method.The SWMM can quantify the water permeability and water purification benefits of permeable pavement in the use stage,and can get the differences of water permeability and water purification benefits of permeable pavement under different maintenance methods.From the perspective of maximizing environmental benefits,daily cleaning + high-pressure washing is the best maintenance method of permeable cement concrete pavement,while manual cleaning + vacuum pumping is the best maintenance method of permeable brick pavement.Service life is also an important factor in the environmental performance of permeable pavement maintenance methods.It is suggested to comprehensively consider the service life and select appropriate maintenance methods to reduce the resource and environmental impact of permeable pavement.The coupling application of LCA and SWMM can more accurately quantify the environmental benefits and key influencing factors of permeable pavement in the whole life cycle.In the construction of sponge city,we should not only pay attention to the rainwater runoff reduction and purification effect of permeable pavement,but also form a regular and efficient maintenance method to minimize the environmental impact of permeable pavement in the whole life cycle and give full play to the utility of infrastructure construction of sponge city.This method is also expected to be applied to the systematic evaluation of resource and environmental impact of other Low Impact Development(LID)facilities and even the whole sponge city,and provide a valuable reference for the environmental impact control of sponge city construction projects.