Study On Behavior Of Skid Resistance Of Asphalt Pavement Based On Road Surface Texture

Skid resistance of asphalt pavement plays an important role in vehicle safety.Good skid resistance of asphalt pavement can ensure that the vehicle has good traction in the process of driving,without slipping.However,under the rainy days,the existence of water will lead to the decrease of adhesion between tire and pavement,thus increasing the risk of vehicle out of control due to tire slip.Moreover,with the rapid growth of traffic volume and the continuous appearance of heavy vehicles,many high-grade highways gradually expose the phenomenon of insufficient skid resistance,which affects the safety of vehicles.Considering the problems existing in skid resistance of asphalt pavement,the laser scanning,CT scanning,finite element simulation and indoor accelerated pavement test were used to analysis the correlation of characterization indexes of skid resistance,the contact condition of tire-pavement under wet condition and the attenuation characteristics of skid resistance of asphalt mixture.Firstly,the texture data of three different types of pavement（AC-13、SMA-13 and OGFC-13）were acquired through laser scanning,and the correlation between texture parameters and skid resistance was analyzed.And the surface texture characteristics of different types of pavement were further analyzed by calculating the power spectrum and fractal dimension of pavement.Secondly,the three-dimensional pavement finite element models of different types of pavement were established by CT scanning and laser scanning,the finite element model of three-dimensional tread tire was generated by rotating axisymmetric model in ABAQUS software,and the hydroplaning process of tire-pavement was realized by Euler-Lagrange coupling（CEL）method and the condition of tire-pavement contact under different conditions was analyzed.Lastly,epoxy asphalt mixture and SBS modified asphalt mixture were loaded under high temperature and normal temperature through indoor accelerated loading equipment,the variation of skid resistance of asphalt pavement was analyzed and the feasibility of epoxy asphalt in long-term skid resistance improving of asphalt pavement was explored.The conclusions are as follows:（1）The skid resistance indicators(BPN、DF₆₀)have a good correlation with the amplitude related indicators and the overall related indicators of the texture parameters,but a poor correlation with the spacing related indicators,among which the correlation between the average dip angle（θ）and the skid resistance indicators is the highest.Amplitude related indicators and overall related indicators can well characterize the skid resistance of pavement,while spacing related indicators are not suitable to characterize the skid resistance of pavement.（2）The finer the mixture gradation is,the greater the fractal dimension is.The fractal dimension of the mixture of the three gradation types is AC-13>SMA-13>OGFC-13.（3）The increase of tire inflation pressure can improve the contact force and the hydroplaning speed.The increase of the water film thickness will reduce the contact force and decrease the hydroplaning speed.Under the same conditions,OGFC-13 has greater contact force,larger hydroplaning speed and higher adhesion coefficient than AC-13 and SMA-13,which indicates that OGFC-13 pavement has better skid resistance than the other two pavement types.（4）Under the same loading conditions,epoxy asphalt mixture has lower MTD,MPD,BPN andθattenuation speed and attenuation rate than modified asphalt mixture,and with less surface texture loss and surface wear,which indicate that epoxy asphalt mixture has better long-term skid resistance than modified asphalt mixture.