Multi-objective Optimization Decision Of Asphalt Pavement Maintenance Based On LCA

With the rapid development of highway construction,our country has been transformed into a development idea,more attention has been paid to the highway maintenance problem,and with the further improvement of highway network,highway maintenance cost begins to become more and more higher year by year;At the same time,under the background of "carbon peak,carbon neutral" goal and green highway policy guidance,the environmental impact of asphalt pavement maintenance process has been paid more and more attention.In the process of road maintenance,from the perspective of the whole life cycle,a lot of fossil fuels will be consumed and a lot of gases and pollutants affecting the environment will be discharged.Therefore,more and more attention has been paid to the maintenance scheme that takes into account social benefits,economic benefits and environmental benefits.It is of great significance to realize the multi-objective optimization research of road performance,cost and environmental impact for the sustainable development of roads.First of all,this thesis predicts the decay model of the local road network pavement performance,through which the performance changes of all sections within the road network are predicted,and the overall average performance level PCI of the road network in the next five years is calculated.Secondly,this thesis innovatively adopts the Gaussian curve fitting method to carry out peaking fitting on historical conservation data and determine the conservation effects of different conservation methods under various intensities.Thirdly,based on the principle of life cycle assessment,the life cycle assessment models of four common conservation methods were established,and the emissions affecting global warming potential(GWP)were taken as the main evaluation index to calculate the carbon dioxide equivalent emission values of the four conservation methods.Finally,based on the cost quota method,the maintenance cost of the four maintenance methods was analyzed from the perspective of the whole life cycle.After completing the above research content,this thesis established a multiobjective optimization model,which took maintenance cost,average performance of road network and environmental impact as the research objectives.Based on genetic algorithm NSGA-II,Matlab was used to program the optimization solution.After optimization,Pareto optimal solution set can be obtained,and evaluation function can be used to evaluate and analyze the optimal solution in the set,and finally realize the decision of maintenance scheme.This thesis analyzes and compares the results of two optimization methods,linear programming solution and Pareto solution.Under the condition of the same maintenance cost and environmental impact,Pareto solution can realize the optimization of the overall average performance of the road network,so the feasibility of this algorithm is determined.Finally,two evaluation functions of efficacy function and Mahalanobis distance are analyzed and compared,and it is concluded that the evaluation method of efficacy function is more suitable for the decision-maker’s preference,and the evaluation method of Mahalanobis distance is more suitable for the situation without conditions to achieve a more balanced decision.The research results further enrich the theory of road maintenance optimization,promote the cross integration of environmental protection and road maintenance,and have theoretical significance and practical value.At the same time,the research results can also provide a new thinking Angle for the road network maintenance optimization decision,and realize reasonable optimization from multiple perspectives such as environmental impact,maintenance cost and average road network performance,which has important reference value.The research results further enrich the theory of road maintenance and maintenance optimization,promote the cross integration of environmental protection and road maintenance,and have important theoretical significance and practical value.At the same time,the research results can also provide a new thinking Angle for road network maintenance optimization decision,and realize reasonable optimization from the aspects of environmental impact,maintenance cost and average road network performance,which has important reference value.