Research On Regularity Of Skid Resistance Regradation Of Asphalt Pavement Based On Full-scale Pavement Loop

The number of casualties caused by traffic accidents remains high every year.Many countries around the world have investigated the road traffic safety for a long time,and found that the anti-skid performance of road surface has the greatest influence on the traffic safety.Therefore,various countries have promulgated the delivery acceptance index of anti-skid performance of asphalt pavement.However,the anti-skid index of new asphalt pavement in our country can meet the specifications.Due to wheel load after open traffic,the attenuation rate of anti-skid performance is too fast.Therefore,in order to facilitate the verification and analysis of the life-span anti-skid performance of asphalt pavement surface layer,this paper compares and analyzes the decay law of anti-skid performance of asphalt pavement of different gradation types through indoor test and onthe-spot inspection work based on the Beijing Full-scale Pavement Test Loop Project.Firstly,the influence of different pavement combination structures on the skid resistance of the same surface layer is analyzed.The dynamic modulus of different asphalt mixture was measured by uniaxial compression dynamic modulus test and the overall modulus of asphalt pavement of each pavement structure is calculated.By comparing the relationship between the overall modulus of asphalt pavement and the anti-skid coefficient,it shows that the overall conversion modulus of asphalt surface layer has no obvious relationship with the anti-skid performance of the surface layer.Therefore,the main research object of anti-skid performance is asphalt pavement surface.Secondly,the influence of temperature on the anti-skid performance of asphalt pavement is analyzed.In this paper,the relationship between temperature and pendulum value is established by the measured pendulum under different temperature conditions,and the correction model of temperature is put forward.The results show that both the rubber slider and the surface layer are in a rigid state at low temperature,which results in the reduction of the effective contact area between them and the contact and insertion between them are insufficient and not firm enough,and the asphalt in the surface layer is easy to migrate and fill the surface micro-structure at high temperature.The friction coefficient of asphalt pavement will be reduced when the temperature is lower or higher.When the temperature is close to 20 ?,the friction coefficient of asphalt pavement is the highest.Then according to the friction coefficient and structure depth measured on asphalt pavement,the anti-slip decay law of four kinds of gradation is compared and analyzed,and the effects of different grades on the friction coefficient and structural depth decay law of surface layer are compared qualitatively.The logarithmic function model is used to fit the data with higher correlation.Finally,the influence of gradation characteristics on the law of anti-slip decay is analyzed.The theory of Bailey method gradation design and theory of fractal are introduced,and then many parameters which can represent the grading characteristics are selected.Based on the method of grey correlation analysis,the key factors affecting the anti-sliding durability are selected.Analyze the specific impact of the key factors one by one and complete the secondary screening of the key factors.The analysis shows that it is difficult to take into account the durability of the two indexes of friction coefficient and texture depth of asphalt pavement at the same time.By adjusting the key gradation parameters to improve the durability of friction coefficient,the durability of structural depth may be adversely affected.Therefore,the design of gradation of asphalt surface layer should be adapted to local conditions.For areas with large rainfall,the structural depth should be considered first.For areas with general rainfall,the effect of gradation on anti-sliding durability can be considered from the angle of friction coefficient.