Comprehensive Benefit Analysis Of Maintenance Project Of Arterial Highway In Mountain Area Based On Life Cycle

According to the trend of national highway construction and maintenance,highway maintenance will be the main trend and focus direction.At present,there are many pavement maintenance technologies,which have different maintenance effects.Traditionally,the choice of maintenance programs only considers the restoration of pavement structure and function,which focuses on initial effects and ignores comprehensive consideration during the life cycle.This paper first investigates the traffic conditions and maintenance plan of asphalt pavement of 135 arterial highway in Chongqing in the past five years.Furthermore,based on the quota,the environmental benefits and economic benefit of different maintenance programs are analyzed;finally,in order to evaluate the comprehensive benefits of different maintenance projects in the life cycle of asphalt pavement overhaul of mountainous arterial highway,based on the analytic hierarchy process(AHP),the factors such as energy consumption,carbon emission,economic cost and service life of pavement were taken into account,and the comprehensive benefit rate of different maintenance program combinations was determined.The main conclusions are as follows:According to the survey,it is found that the most common overhaul and maintenance plan of common trunk roads in Chongqing is to mill the asphalt layer and the base layer,and then lay down 20cm cement stabilized crushed stone from bottom to top.+5cm ordinary AC-16+4cm SBS modified AC-13,(the utilization rate of 10.4%);common national road with asphalt layer for the 5cm ordinary AC-20+4 cm SMA-13 structure(the utilization rate of 3%).In addition,in order to promote the application of low-carbon environmental technology,part of roads used a 10cm foam asphalt plant mixing cold regeneration,overlaying 4cm SBS modified AC-13 structure.In this paper,the three periods of the life cycle of the overhauling and maintenance project of the mountain trunk road are defined as follows:The road overhaul period includes the milling of the paving base,the milling of the lower layer(or the regeneration of the lower layer),the milling of the overlay Grass-roots)process;the operation maintenance period includes daily asphalt pavement maintenance,preventive maintenance and minor maintenance;the life ended period represents the end of the road life and began brewing next asphalt pavement overhaul maintenance works.From the asphalt pavement maintenance program to implement the whole process of view,for overhaul maintenance of the top layer program,average energy consumption,the average carbon emissions and the average cost of mill resurfacing 1m3 common asphalt concrete are 1840.26MJ,154.31kg,and 1364.92 yuan.Compared to SBS AC-13 and SMA-13,savings of energy consumption,the average carbon emissions and the average cost reach 28.3%and 38.4%,12.4%and 24.9%,12.9%and 27.5%,respectively.For overhaul maintenance of the lower layer program.the energy consumption,carbon consumption and carbon emission of 113 foam asphalt plant cooling regeneration are 724.92MJ,66.16kg,657.62yuan,which are less than 60.2%in energy,56.7%in carbon emissions and 49.61 in costs compared to 1m3 common asphalt concrete;in the preventive protection programs,the energy consumption of lm3 MS-2 microtiter was 1421.00 MJ;the carbon emission was 132.92kg and the cost was 1310.67 yuan.the energy saving was 8.8%,the emission reduction was 10.1%and the cost saving was 11.3%compared with 1m3 ES-2 slurry layer;the energy consumption,the carbon emission and the cost of hot-in place recycling are 1056.07MJ,63.57kg and 1500yuan,which saves 35.5%of energy consumptions and 59.2%%of carbon emissions,but increase 12.2%of costs compared to thin layer covers.The best maintenance program is milling 20cm cement stabilised crushed stone+milling 5cm AC-20+milling 4cm SMA-13 in overhaul maintenance period+4cm hot in-place recycling in operation maintenance period,for this program,the energy consumption is 1412575MJ,carbon emission is 173181kg and economical cost is 868982 yuan.Compared to traditional program,it can save 1.9%of energy comsuption,2.9%of carbon emissions and prolong 20.0%-33.3%lifetime.Although the economic benefits are not obvious,but hot in-place recycling has excellent environmental benefits,while SMA-13 and hot in-place recycling can prolong service life and make up poor economic benefits,and the comprehensive benefit reaches 6.3%?12.4%.