Research On The Skeleton Deformation Characteristics Of Asphalt Mixture In The Hot And Humid Environment

Asphalt pavement has the advantages of sound absorption,noise reduction,comfort and good skid resistance,so at present,the main highway construction at home and abroad is asphalt pavement.But with a large number of asphalt pavement construction,the rut distress becomes a growing problem,shear deformation had been caused to the asphalt pavement in the course of driving,which brings huge challenges to the service life of pavement and the safety of the vehicle.In addition,the south,where the weather is hot and humid,is more susceptible to the destruction of the rut disease.Due to previous studies on rut damage of asphalt pavement mainly focused on the influence of single factor,the shear failure of asphalt pavement mixture under the coupling of multiple factors is rarely analyzed.In this paper,orthogonal test method is used to divide test conditions with different temperature and humidity,different load,different wheel speed coupling into 9 groups.After that,the regular patterns of rut deformation rate,uplift coefficient,creep rate under different loading times are investigated respectively under the 9 test conditions.Furthermore,the influences of temperature,humidity,load and wheel speed on the rutting macro-properties are also analyzed by statistics method.After being examined and summarized,the relevant test data indicate:(1)temperature makes the greatest contribution to rutting deformation rate and Hamburg dynamic stability,humidity is the second and wheel speed is last.(2)the coefficient of uplift is related to the rolling times of steel wheels,and doesn’t be affected by changes of four factors.(3)when the temperature rises to 60℃,under water immersion test conditions,specimen damage has increased dramatically.Industrial CT is adopted to scan specimens’ cross-sectional layer under 9 test conditions.Afterwards,the CT scan images are being processed by softwares like Matlab,ImageProPlus.By analyzing the changes of the volume of air voids and area of coarse aggregate size among the different cross-sectional layers in the 9 groups,the interaction mechanism among the factors is further studied.It is found that when test condition is 60℃ and water environment,temperature and water interaction mechanism,to a large extent,weaken the strength of bituminous mixture of specimen’s under layer,which is the main cause of suddenly intensified damage to the specimen.In this paper,the study of the mixed material damage under the coupling condition of temperature,humidity,load and wheel speed,can provide reference for the rutting distress in the southern humid environment.