The Calculation Models And Evaluation System Research On Asphalt Mixture Life Cycle Carbon Emissions

Greenhouse effect is one of the major environmental problems in the world,and all countries have taken active measures to control "carbon" emissions.The carbon emissions generated by China's transportation industry are at the forefront of all industries and are an important area for promoting a low-carbon economy.Since the rapid development of the highway,the energy consumption of the project is huge throughout the life cycle,but the domestic standard to calculate the carbon emission have not been quantified.The overall carbon emissions is measured and calculated to evaluate the "green" level of each project,which encourage low-carbon process innovation and urge the whole industry to follow energy-saving and emission reduction policies.Therefore,it is necessary to establish a carbon emission calculation model for the life cycle of a road project and an evaluation system for low-carbon roads.The entire life cycle of asphalt mixture were divided into four stages:material production,construction,maintenance,demolition recycling.Also the system boundary of carbon emission measurement in each phase was defined.According to the current construction technology,the main source of the overall carbon emissions during the construction of asphalt pavement consist of the energy consumption of machinery and equipment.And base on that,the carbon emission measurement list was established.A hybrid life cycle assessment(LCA)method combining process-based LCA and economic input-output LCA was used to establish a carbon emission calculation model.The pavement structure of a typical two-lane,four-lane expressway was taken as an example.The amount of construction materials,construction technology,equipment types,and equipment parameters were determined with reference to the construction quota and in combination with actual conditions.Carbon emissions was then calculated,and the key link was found to be material production.At the same time,based on the analytic hierarchy process to establish the weight of each evaluation index,and give the scoring rules for the indicators,an evaluation system for low-carbon roads was established.The weight of each evaluation index was determined by Analytical Hierarchy Process and the detailed rules were given.The total score of a road project was the weighted total of each indicator,and the low carbon level of the road was divided by the total score.In this investigation,the highways of each province are selected for scoring,and the distribution of highways on the low-carbon roads in China is ranked as "large in the middle and small in both ends".Finally,the relevant information based on the feasibility phase of the project was established and back propagation Back-Propagation neural network in MATLAB was employed to predict the overall carbon emissions of the project.The relevant procedures were compiled and some samples were collected for test verification.