The Research On Skid Resistance Performance Of Asphalt Mixture

With the rapid development of expressway construction,the issues of road safety have got more and more attention.Pavement skid resistance has close relationship with the road safety,and the lake of pavement skid resistance becomes the important reason for traffic accidents for expressway.For the current situation that the single evaluation index of the polishing and shape characteristics has been used in the design of mix proportion,it is necessary to utilize the digital image technology on researching these two characteristics of coarse aggregates.In addition,the skid resistance between the tire and pavement extremely depends on the macro,texture of pavement for cars driven in high speed,therefore researching the texture depth changing with gradation parameters becomes necessary.It can also provide basises for the asphalt pavement design on skid resistance.This thesis studies on the aggregates texture characteristic with the Aggregate Imaging System(AIMS),and simulates the polishing process of the aggregates with the Los Angeles Abrasion and carrying on regression analysis with the texture indexes,putting forward the texture characteristic index.Compares the coarse aggregates shape characteristics evaluated by AIMS and IPP,putting forward the shape-characteristics index,then studying the influence of the coarse aggregates' shape-characteristics index on skid resistance and stability in high temperature.Researches the changing law of the texture depths and pendulum value based on the changes of shaping methods and gradation parameters about the asphalt mixture.Put forward the parameter indexes accoding to the skid-resistance demands.The results show that:AIMS can evaluate the texture characteristic of the coarse aggregates effectively.Obtain the changing curve of the coarse aggregates' texture indexes for evaluating the initial skid resistance and the polishing capabilities.The sphericity index could assess the shape characteristics of the coarse aggregates.It is proved that the texture depths and stability in high temperature are deeply influence by the mean sphericity index of the coarse aggregates,and the sphericity index is recommended no less than 0.65.The Superpave Gyratory Compactor(SGC)is proved to be the most suitable method for studyind the pavement skid resistance.Furthermore,the percent passing the 4.75 mm sieve as well as the CA value are considered to have a good correlationship with the texture depth of the asphalt mixture.The NCHRP 441 model and the optimized NCAT model could estimate the mean texture depth of the asphalt mixture on no segregation conditions.