Digital Simulation Methods For Surface Textures Of Asphalt Pavement

Skid-resistance performance is important in evaluating the safety status of highways, and pavement textures are contributing factors in deciding skid-resistance performance. As for asphalt pavements, the textures have direct influences on tire-road contacts and therefore on braking performance and stabilities of vehicles. So the relationships between pavement textures and friction need to be carefully discussed. Meanwhile, it is proved to be valid to utilize digital simulation methods to replace field tests on friction evaluation given the advanced digital simulation techniques. This paper develops a protocol to scan surface textures on pavements specimen and then calculate the friction index based on software and laser scanning equipment. Finally the access for inputting friction index using mechanical simulating software is developed and braking performance of vehicles on pavements with different friction coefficients are evaluated.First the HOLON 3DS laser scanner was utilized to scan the asphalt pavement specimen to get the data of surface textures. Then the Geomagic studio was used to conduct coordinates transformation to ensure that the coordinates of textures were in accordance with the ground coordinates.Then the prediction equation on friction coefficient based on Macro Textures was raised based on previous studies. Variables in prediction equation was calculated using MATLAB. When calculating Mean Profile Depth, the calculations of Modified Mean Texture Depth was raised to replace MPD and this method was proved to have good correlations with MPD. Influences of different variables in prediction equation on friction coefficient were also discussed.Finally, the vehicle,3-D road and braking test models were established in CarSim to determine the influences of pavements with different friction coefficients on braking performance of vehicles. The suitable braking pressure was decided based on several simulating tests. After the calculations of models, the efficiency of different outputting dynamic mechanical index of vehicles on evaluating braking performance was discussed. The suggested range of friction coefficient on pavements was 0.45 to 0.7.