Study On Slab-Junction Blocking Mechanism And Clearing Technology Of Permeable Asphalt Pavement

Permeable asphalt pavement is a kind of functional pavement with high permeability.The realization of its good drainage,noise reduction and other functions mainly depends on the high porosity formed by the open-graded mixture.Due to the complex pore distribution in the mixture,most of the silt on the road surface will remain inside the pavement after it enters the mixture with rainwater.It is easy to cause the siltation of permeable asphalt pavement to shorten the service life of the pavement.Understanding the characteristics of siltation behavior of permeable pavement is essential for the development of silt prevention and dredging technology in the future.This paper relies on the project of Jilin Provincial Department of Science and Technology ’ Research on Key Technologies of Comprehensive Prevention and Control of Permeable Pavement Silt in Sponge City Construction ’.In this paper,based on the characteristics of the actual road silt,through the self-developed silt simulation equipment for permeable pavement silt simulation,the influence of silt type and particle size on silting behavior is analyzed by grey correlation theory.Subsequently,the industrial CT scanning technology was used to scan the same Marshall specimen for multiple times with different degrees of siltation.The Avizo and VG Studio Max software were used to analyze the silt in the pores,and the transparent channel siltation experiment was used to simulate the formation of plate siltation.Finally,the standard electromagnetic vibration table was used to study the optimal disturbance frequency of plate silt,and the ultrasonic cleaning machine was used to clean the plate silt specimen.The results show that there are great differences in particle size distribution of silt in different regions and seasons.The silt in rainwater runoff contains 27.6 % clay minerals.The permeability coefficient of silt simulation specimen without dry-wet cycle is significantly greater than that considering silt cycle.The results of grey correlation analysis show that the influence of silt on permeable asphalt pavement is0.15 mm graded sand > 0.3 mm graded sand > 0.6 mm graded sand > fine clay > 1.18 mm graded sand > 2.36 mm graded sand.The most easily silting position is about 0cm-2.6cm below the road surface.The deeper the road surface is,the smaller the silting degree is.Large space pores near the specimen surface and connected pores with large longitudinal depth and small tortuosity are easy to silt;There are three processes of silt in the channel,namely,stagnation,erosion and disintegration,and accumulation of silt.These three processes occur every time the silt cycle,and constantly change the structure of silt in the permeable pavement.The permeability coefficient recovery of the specimen is the largest when the frequency is between 100 and 400 Hz,which indicates that the optimal disturbance frequency of the permeable asphalt pavement is within this range.