Research On Asphalt Pavement Skid Resistance Performance Evaluation Method Based On Tire-Pavement Effective Contact Characteristics

Improving the skid resistance performance of asphalt pavement has become the key technology to ensure traffic safety.And the actual contact characteristic between tire and pavement texture is the emphasis to study pavement skid resistance performance.The current specification mainly uses texture depth and friction coefficient to evaluate the overall skid resistance level of pavement.However,the contact characteristics between tire and pavement cannot be reflected,which is closely related to the skid resistance performance.In previous research,the road surface was assumed to be a smooth interface with a certain friction coefficient which was obviously not conformed with the real case.Based on the above situation,the dissertation took the pressure-sensitive film system and the three-dimensional laser scanner as the main method,and took the tire-pavement contact characteristics as the principal line.A systematic study about the tire-pavement contact stress distribution by the contact mechanical view has been made to reveal the interface contact characteristics of the meshing degree between pavement micro-and macro-texture and tire.Firstly,the limitation of the truncated range of the pressure-sensitive film system has been improved in order to obtain the complete contact stress distribution between the tire and the pavement.The characterization model and the evaluation method of the non-uniform distribution of tire-pavement contact stress has also been established.Secondly,a three-dimensional laser scanning equipment has been developed to measure and reconstruct the accurate texture of asphalt pavement with the advantage of high-efficiency and high-precision.Finally,the asphalt pavement skid resistance performance has been evaluated based on the morphologic characteristics of the effective texture between tire and the pavement,in order to reveal the change law of the tire-pavement contact interface during the skid resistance performance attenuation process.,The research work in this paper had great theoretical value and application potential in whether the evaluation of skid resistance performance or the design and construction of asphalt pavement.The main processes and innovations of this dissertation have been shown as follows:(1)The dual target adaptive value function has been constructed based on the pixel gray level and the contour feature.An optimization algorithm called Dynamic Reference Image Registration(DRIR)has been proposed to register and fuse the test results of multi-scale pressure-sensitive film.Mutual information and contact stress values were used to quantitatively evaluate pressure-sensitive film fusion effect.The algorithm was utilized to solve the limitation of the single gauge range of pressure-sensitive film.And it could objectively and accurately obtain the three-dimensional contact stress distribution between the tire and the rough pavement.The study provided a novel method for promoting the understanding of the tire-pavement contact characteristics,with the advantage of higher accuracy,simple operation and low price.(2)Further study was conducted to the point contact state of different tires and pavements under different test conditions,and a three-parameter Weibull distribution model has been built up to characterize the random distribution of tire-pavement contact stress.In order to describe the dispersion of stress distribution under different contact states,a shape parameter evaluation index based on contact stress distribution curve was presented.The stress concentration effect of tire contact stress on rough asphalt pavement was beyond imagination.In order to quantitatively evaluate the contact stress concentration phenomenon between tire and asphalt pavement,the average value and the peak value of contact stress,and stress distribution index were proposed,which can evaluate the contact stress concentration from overall to each part.(3)Based on the non-contact laser triangulation method,a high-efficiency and high-precision three-dimensional laser scanning system has been developed.The accuracy and stability of the device were verified by the three-dimensional reconstruction calibration and error analysis of the standard gauge block.A suitable method for calculating the mean depth of three-dimensional surface model has been established based on the principle of texture depth,which can help to improve the subjectivity of MTD and overcome the under-representation of MPD.Based on the 3D texture model,a structural cutting method was proposed to evaluate the spatial distribution of asphalt pavement surface texture.The multi-scale evaluation system for rough texture of pavement surface was established.The macrotexture distribution density index(SMA)was put forward to describe the macrotexture distribution state of asphalt pavement based on the macro-scale model.The microtexture distribution density index(SMI)was proposed to characterize the richness of microstructure on the pavement macrotexture's surface by the micro-scale model.(4)The effective depth of tire contact has been calculated through the spatial contact relationship between tire and pavement.The multi-scale index was established to evaluate the extracting 3D morphological information from the tire-pavement contact interface.The skid resistance performance attenuation process of asphalt pavement was simulated by the laboratory kneading test,and dimensional analysis was made for the contact stress distribution characteristics and texture morphology changes of asphalt pavement.The index of the effective contact texture could evaluate the asphalt pavement skid resistance with good performance,and its rationality was verified.The experiment results indicated that,the design of skeleton structure asphalt mixture could help to improve the embedding effect and stability of the pavement structure.In addition,the use of high-performance asphalt binders could impose strong constraints on the main skeleton,and it could also significantly increase the asphalt pavement skid resistance performance and durability.(5)The research results have been applied to the construction of the new expressway test section,and the rationality of the tire effective contact evaluation index has been verified.The quality control of the asphalt mixture construction process was carried out,and the skid resistance performance of the test sections of different roller compacted schemes were compared.The tracking observation results show that reasonable construction technology and roller compacted scheme was able to improve the skid resistance performance of asphalt pavement effectively.A series of the creative researches,such as the description of non-uniform distribution of contact stress,the three-dimensional reconstruction of the pavement texture,the multi-scale evaluation of the effective contact texture,engineering application and verification in terms of tire-pavement effective contact mechanism were carried out in this paper.These researches provide new ideas for evaluating pavement skid resistance performance,and provide theoretical basis and technical support for the development of high-performance tires,the design of anti-sliding asphalt mixture,and the analysis of vehicle-road mechanical simulation.