Study On The Evaluation And Timing Of Asphalt Pavement Preventive Maintenance On Zhangjiakou

Along with the increase in highway construction investment,China's highway mileage numbers increase.On cold area the temperature is low,the temperature difference is large,the geological condition is complex,so the road environment is bad,and it is easy to occur for the early different levels of damage in the process of the use of asphalt pavement,such as asphalt aging,cracks,settlement and so on,which can lead to declining performance and structural performance year by year.When the road structure is good,only a slight damage,the appropriate preventive maintenance measures is timely taken,which not only can make the pavement structure damage can be effectively mitigated or prevented,but also can make the road conditions are improved,driving quality is improved,and its service life is extended.Therefore,it is necessary to study the Highway asphalt pavement preventive maintenance in cold area.Based on the reality of road maintenance in Zhangjiakou area,mainly to study the following:(1)It is introduced that the research background,purpose and significance.And it summarizes the current situation of research and development of preventive and maintenance technology at home and abroad,and the shortcomings of our country in the pre-maintenance.(2)Vehicle-based intelligent detection vehicles and three-meter ruler and other equipment are used for road surface testing.Through analysis of road surface roughness,damage and rutting test results,and site investigation,it is evaluated that application result of slurry seal and micro surfacing.The results show that the slurry seal and the micro-surface technology have some improvement effect to improve the road roughness,road surface damage and road rutting.(3)Field sampling is carried out,in order to drill the asphalt samples from conservation sections and unprotected sections.Through laboratory test determining asphalt sensitive-temperature property,low temperature performance and high temperature performance of the indicators,it is evaluated the influence o-f preventive maintenance measures for asphalt performance by analyzing perfor-mance indicators.The results show that the penetration and ductility of pavem-ent taking the slurry seal and the micro-surface technology are improved,and the selected section is the cold area of Zhangjiakou.It can be seen that both t-echniques can effectively slow down the decay rate of low temperature performance of asphalt(4)Aiming at the shortcomings of the existing evaluation methods and the evaluation system,the asphalt performance index and the pavement performance index were taken as the evaluation indexes of the asphalt pavement,and a new evaluation system was put forward.The improved EW-AHP method was used to determine the performance index weights.The method,combining the qualitative and quantitative and the subjective and objective,provides the basis for pavement management plans.This evaluation system is established for class 2 and below highway of the national highway.Through the engineering example is analyzed,this method,to a certain extent,makes the subjective and objective combine,so that the results have a strong credibility.(5)The pre-curing timing is discussed theoretically and qualitatively based on the research and norms.The international leveling index IRI is selected as the judgment index of the conservation time.And the preventive maintenance model of asphalt pavement is established according to the decay law of IRI and the cost of conservation.