Analysis And Prediction Of Skid Resistance Behavior Of Pavement Under Ice And Snow Conditions

China has a vast territory and very complex meteorological conditions,in where the alpine region occupies a huge area.It means that in winter and early spring,road snow and ice disasters will last a long time with a wide range affection,and cause deep damage,which seriously endangers the safety of people’s lives and property.As one of the materials with the least friction on the earth,ice has complex and changeable physical and mechanical properties,which are easily affected by the surrounding environment.Therefore,the introduction of ice or snow medium into the friction system significantly changes the interaction mechanism of the friction pair,which greatly increases the complexity of the research on the anti-skid performance of snow and ice pavement.It is difficult to obtain the tri-phase contact state of the Tire-Ice-Road by the traditional evaluation and research methods,and the failure cause of anti-skid performance of ice-containing asphalt pavement can not be explained from the mechanism.On the other hand,the lack of long-term monitoring data also restricts the development of frictional model of snow and ice pavement.In view of this,this thesis focus on theice filling system of asphalt pavement texture.Based on the method of multi-scale methods,the surface morphology characteristics of asphalt mixture during its lifetime is studied.Then,the evolution law of morphology characteristics of snow and ice covered pavement is discussed with the method of indoor simulation ice solidification test and simulation analysis.A test platform is developed to monitor the anti-skid performance of snow & ice covered pavement.On this basis,the influence of melted water film on the tire-ice-road 3-phase contact system is considered,and the prediction model of the frictional performance of snow and ice road is studied,which will provide the basis for scientific and reasonable evaluation of the icy pavement anti-sliding performance.The contents and results are shown as follow:The 3d structural feature points of asphalt mixture were obtained by industrial Computerized Tomography,then the surface morphology of asphalt mixture was extracted by image morphological processing and evolutionary matching algorithm.The effect of tire load on the long-term abrasion of asphalt pavement is simulated through Aachen Polishing Machine test,and the trend of the life-cycle evolution of the asphalt pavement’s topography is analyzed.By comparing the power spectral density of asphalt pavement morphologies at different wear stages,a segmented evaluation method based on spectrum fractal method was proposed.Combined with the spectral fractal parameters and the statistical geometric parameters,a multi-scale evaluation index for the surface topography of asphalt pavement was proposed.According to the characteristics of the factors affecting the icing process on the low temperature surface,a simulation test chamber and test method for the icing process on the asphalt pavement,which can reflect its environmental characteristics,are developed.The effects of temperature,freezing time and moisture content of wet air on the icing process were analyzed.Based on Gibbs free energy theory,the computation model of ice coagulation and frost formation on asphalt pavement was established with finite element software ANSYS/Fluent.Based on the statistical method of supporting area ratio,the influence coefficient of ice film pollution α was put forward to evaluate the morphology characteristics of asphalt pavement during ice film ablation.Based on the accelerated loading test method,a test platform was developed to test the frictional behavior of icy pavement.The stability evaluation of the test equipment under different pavement conditions is verified,and the operating condition and test method of the equipment are put forward.The influence of ice film formation on the frictional behavior of asphalt pavement was studied through experiments,The durability of the influence of ice film on the anti-skid performance of asphalt pavement under different working conditions was analyzed.By comparing the frictional behavior of pavement in different wear stages,it can be pointed out that the ice film have along-term effects on anti-skid performance for asphalt pavement after wear.The Persson contact theory is extended,combined with the phase change principle of the ice crystal and the dynamic effect of melted water film,a time-dependent differential equation is obtained to describe the three phase contact states of the Tire-Ice-Road.Finally,the prediction theoretical model of friction behavior of asphalt pavement under ice conditions is established.The viscoelastic parameters of tread rubber material can be obtained by dynamic mechanical analysis for deducing the parameters of rheological model in the friction prediction model.Based on the principle of model construction,the prediction process of friction behavior of ice-bearing pavement is defined.The simulation results are compared with the test results to verify the validity of prediction model.A series of works,such as the development of friction test system of snow and ice pavement,the development of prediction model study of anti-skid of snow and ice pavement and the frozen process of pavement in cold areas,were carried out in this paper.These researches will promote the development of frictional research of snow and ice pavement and the implementation of road safety measures in winter in China.