Structural Design Process Optimization Of Asphalt Pavement Based On LCA-LCC

In the recent decades,with the development of China's technology and economy,people's living standards have been significantly improved,thus increasing requirements are proposed on the infrastructure.Trasportation plays an important role in the development of economy,leading to higher requrements on the quality of highway.Asphalt pavement has been widely applied to road construction,considering its advantages such as flatness,confortable driving,good durability and excellent sliding resistance.However,the construction of road needs to consume a host of resources,emitting a large amount of pollutants such as greenhouse gases,acid gases,and solid particulates,and environmental pollution is becoming increasingly serious.Among the pollutants,greenhouse gases can cause the global warming due to the greenhouse effect,which is gradually affecting the natural ecosystems such as climate anomalies,rising sea level,and changes in the distribution of flora and fauna.To date,most investors mainly consider the economic benefits,however,with the increasing awareness of environmental protection among the people,the simple economic benefits cannot meet the requirements of sustainable development.This paper investigates and analyses three aspects of the asphalt pavement:energy consumption,emissions,and economy,respectively,based on which the performance of the asphalt pavement is comprehensively evaluated and optimized design method is proposed.This paper firstly introduced the life cycle assessment?LCA?and life cycle cost?LCC?,and analysis on the current research status of integration of LCA and LCC was conducted.Then,the design process of asphalt pavement in the 2017 edition of Specications of Design of Highway Asphalt Pavement?JTG D50-2017?and the highway asphalt pavement design and verification program HAPDS were introduced.The details of the aspalt pavement structural layer under heavy and medille traffic load were preliminarily designed.Secondly,the construction period of asphalt pavement was divided into three stages:material preparation stage,transportation stage,and construction stage.Three basic inventories of the energy,raw materials and mechanical equipment were firstly prepared,based on which the inventories of energy consumption,CO₂ equivalent emissions(CO_2eq)and budgets during the three stages of asphalt pavement construction period were determined.Finally,the thickness of structural layer and thickness range of the control layer were preliminarily determined according to the survey results of the asphalt pavement structure and the Specications of Design of Highway Asphalt Pavement?JTG D50-2017?.The HAPDS program was adopted to calculate the optimal thickness of the asphalt pavement control layer with different parameters,including types of the base layer?semi-rigid base layer and flexible base layer?,bidirectional annual average daily traffic volumn of vehicles with 2 axes,6 wheels or above?AADTT?,resilience modulus of the top of base layer,and thickness of the control layer.The corresponding energy consumption,CO_2eq emissions,budgets and environmental economic comprehensive cost indexes of the asphalt pavements during the construction period were calculated and analyzed according to the prepared inventories,and the influence of parameters on the energy consumption,emissions,and economy proformance of pavement was discussed.Then relevant suggestions were proposed for the design of pavement during the construction period.