Influence Analysis Of Graded Macadam Base On Rut Of Asphalt Concrete Pavement

Asphalt mixture is a kind of temperature sensitive material.In different seasons,the compression modulus of asphalt mixture varies greatly.It is small at high temperatures in summer and very large in winter.Asphalt pavement will produce rut due to the continuous action of vehicle loads.The driving safety of the driver is greatly affected by the pavement rut(The sum of deformation of subgrade,base and asphalt surface of asphalt pavement structure under the action of vehicle load).The reduction of thickness of the asphalt surface(Under the action of vehicle load,the thickness of the surface on the asphalt pavement will gradually decrease.The reduced thickness is called the thickness reduction of the surface.It only refers to the reduction of the thickness of the asphalt surface.)has a great influence on the durability of the asphalt pavement.The durability of asphalt pavement is negatively related to the reduction in surface thickness.The base is different,so their asphalt pavement performance is different.Therefore,it is of great significance to study the effect of different base on the reduction of surface thickness and the effect of asphalt pavement rut.Chinese asphalt pavement base generally uses flexible base and semi-rigid base.Some experts believe that the semi-rigid base's compressive resilient modulus is much larger than that of flexible base layers.Under load,semi-rigid base asphalt pavement will produce relatively smaller rut,which is better to the durability of asphalt pavement.However,in the actual project,the durability of the flexible base asphalt pavement is found to be better than that of the semi-rigid base asphalt pavement.In order to analyze the influence of flexible base on the asphalt pavement rut,semi-rigid base as a control,a modified indoor wheel load test is used for test analysis.Then the finite element model is established to simulate the rutting test,which illustrates the accuracy of the finite element model simulation.According to the asphalt pavement structure commonly used in the project,the asphalt pavement structure with the same asphalt surface and different base is built using finite element software,and analyze the influence of different types of base on the rut of asphalt pavement and reduction of surface thickness.The results of indoor wheel load test and finite element model simulations show that the pavement rut of semi-rigid base asphalt pavement is smaller than that of flexible base asphalt pavement when the load is initially applied,however,when the load is applied to a certain number of times,the pavement rut of the semi-rigid base asphalt pavement will be larger than that of the flexible base asphalt pavement.The thickness reduction of the surface of the flexible base asphalt pavement is always smaller than that of the semi-rigid base asphalt pavement.It shows that the influence of the flexible base on the asphalt surface is more favorable,and the durability of the flexible base asphalt pavement is better.