| With the increasingly perfect road transportation network,road construction is gradually transforming to management and maintenance,and the timely maintenance of in-service roads has gradually become a hot topic in the transportation field.Taking real-time and effective preventive maintenance measures for in-service road can reduce traffic closure and traffic congestion caused by maintenance,eliminate possible road safety hazards,and greatly reduce road maintenance costs.At present,the maintenance strategy of asphalt pavement is mostly based on intuitive pavement diseases such as ruts,potholes,and cracks,and almost ignores the impact of road surface anti-skid performance.Especially,the frequent occurrence of traffic accidents in tunnels and long downhill sections in rainy and snowy weather is closely related to the insufficient antiskidding of the road surface.However,the technical measures for anti-skid recovery of asphalt pavement are relatively mature,which mainly rely on the engineering experience and subjective judgment of experts,and there is no scientific and reasonable method of comparison and decision-making.In view of this,in this paper,combing numerical calculation and finite element simulation,the attenuation law of anti-skid performance of asphalt pavement treated by typical anti-skid recovery technologies and comprehensive applicability of different anti-skid recovery technologies were explored based on asphalt pavement surface texture characteristics and vehicle dynamics theory.Then,the anti-skid performance threshold of road surface under different working conditions was analysed by simulation.Thereafter,the decision-making model of antiskid recovery technology of asphalt pavement based on road surface texture characteristics was established by using BP neural network algorithm.Firstly,based on the texture characteristics of the asphalt pavement and the Persson friction model,the ACRP system was used to collect road surface texture information and calculate the dynamic friction coefficient values under different road conditions.Under dry road condition,the road surface anti-skid performance of asphalt pavement is much higher than that of wet pavement.The higher the speed,the more significant the difference between the two road conditions.When the speed is 55km/h,the dynamic friction coefficient of road surface increases by 0.3063 compared with the wet pavement.From the perspective of pavement,it is found that the selection of mixture aggregate and asphalt quality,grading,mixing and other construction techniques have a significant impact on the anti-skid performance of asphalt pavement.The anti-skid threshold value of the road surface is mainly affected by climatic conditions and road information.Secondly,the four typical anti-skid recovery technologies of fine surface treatment technology,fine anti-skid macadam seal,drainage asphalt pavement and ultra-thin wear layer are selected as the research objects.The ACRP system and Persson friction model are used to evaluate the anti-skid performance of different anti-skid recovery technologies and comprehensive applicability analysis of the four typical anti-skid recovery technologies.The results show that under dry conditions,the anti-skid performance of road surface anti-skid performance is ordered as ultra-thin wear layer>drainage asphalt pavement> fine surface treatment technology> fine anti-skid macadam seal.Under wet conditions,the anti-skid performance of road surface anti-skid performance is ordered as drainage asphalt pavement> ultra-thin wear layer> fine surface treatment technology> fine anti-skid macadam seal.The anti-skid performance of the road surface processed by fine surface treatment technology remains unchanged or slightly improved during the initial period of operation.The anti-skid performance on the heavy traffic road section decreases by about 10% each year,and the medium traffic section is about 8%.With regard to the fine anti-skid macadam seal,it has little change during the initial period of operation.The anti-skid performance on heavy traffic road section in the first year decreased by about 25%,while the medium traffic section was about 17%.In the second year,slowed down,the anti-skid performance of road surface declines slowly with respectively decreased by about 8%,7% on the heavy and medium traffic road sections.As for drainage asphalt pavement,the anti-skid performance of road surface decreased by about 9% on heavy traffic section in the first year,and then the decline rate becomes slower and the annual average decreases about5%.After the operation of the ultra-thin wear layer,the decline rate is relatively even with an average annual decrease of about 10%.The dynamic friction coefficient of the new asphalt pavement processed by the four anti-skid recovery technologies is basically the same.The attenuation rate of road surface anti-skid performance is ordered as fine anti-skid macadam seal > fine surface treatment technology > ultra-thin wear layer>drainage asphalt pavement.The pavement surface thickness and the attenuation rate of anti-skid performance are negatively correlated to a certain extent.Thirdly,based on vehicle dynamics theory,the braking distance and tire sideslip were used as the evaluation indicators for driving safety.Car Sim/Truck Sim was applied to simulate the anti-skid threshold values of road surface on straight road section,downhill section and curved section for different types of vehicles.On straight road section,as the driving speed continues to increase,the increase of road surface dynamic friction coefficient threshold gradually slows down.At the same driving speed,a large cars have a larger dynamic friction coefficient threshold than small cars.When the speed is 40km/h,there is the largest difference between the two types of vehicle,and the anti-skid threshold required for a large vehicle increased by about 28.21% higher than that of a small vehicle.On downhill road section,at the same speed of 20km/h,when the longitudinal gradient is increased from 0.3% to 9%,the anti-skid threshold of the road surface for large cars increases by 0.12,and that for small vehicles is 0.105,indicating that the large cars on the downhill section are more sensitive to change in road longitudinal gradient than that of the small cars.On a curved road section,when the radius of the curve reaches a certain range(R ≥ 95 m),the anti-skid threshold of road surface will gradually stabilize and be equal to 0.11.When the superelevation value increases from 6% to 10%,the road surface anti-skid threshold required by the small cars at speed of 20km/h is reduced by 25.7%,and the required anti-skid threshold remains basically unchanged at speed of 120km/h,indicating there is a significant relationship between the skid resistance of the road surface and the radius of the curve when the design speed is low.Finally,combining the comparison results of different anti-skid recovery technologies and the anti-skid threshold values of asphalt pavement under different simulation conditions,Python programming was used to quickly solve the anti-skid threshold of asphalt pavement and build a visual anti-skid maintenance timing decisionmaking model.The decision-making model of anti-skid recovery technology of road surface was constructed using BP neural network algorithm.Moreover,the double hidden layer BP neural network constructed with Re LU excitation function and MSE loss function has a test accuracy of about 0.88,indicating that the established the decision-making model of anti-skid recovery technology of asphalt pavement has high accuracy.Furthermore,based on the Qt library in Python,an interactive program for the decision-making system for anti-skid maintenance for asphalt pavement was developed,which can provide real-time,fast and visual maintenance strategies of antiskid performance for in-service asphalt pavement.In this paper,the road surface anti-skid performance of asphalt pavement processed by the four typical anti-skid recovery technologies of fine surface treatment,fine anti-skid macadam seal,drainage asphalt pavement and ultra-thin wear layer is taken as the research object.The applicability of different anti-skid recovery technologies and the anti-skid threshold values of pavement surface under different working conditions are analysed,which provides certain theoretical guidance and technical measures for the maintenance time and maintenance decision-making of the anti-skid performance of asphalt pavement. |
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