Field Suvery And Numerical Simulation Of Rutting On Asphalt Pavement In Urban Road

Along with the process of urbanization in China accelerating, theconstruction of urban road is continuously developing. At the same time,a sharp increase of traffic volume occurred in the urban traffic, and someurgent problems, such as the overload, heavy-load, etc., existed in theurban traffic. The above problems resulted in the early damage (such asthe rutting) to the asphalt pavement in the urban road. The rutting is aserious threat to the traffic safety and operational quality of the asphaltpavement. Therefore, it is significant to investigate the rutting in theasphalt pavement of urban road.In this paper, the distribution of rutting was surveyed and themechanism of the rutting has been explored in the urban road, forexample, the asphalt pavement in Hangzhou city. The3D finite elementanalysis (FEA) model of asphalt pavement was built using the platform ofABAQUS software. Long-term performance under traffic loads wassimulated by ABAQUS/Explicit module. The dynamic response, theevolution of rutting and the technology of resistance to rutting wereanalyzed.By means of summarization of research results, some conclusionscan be made as follows:(1) In the urban road, the rutting, together with other distress, usuallyoccurs in or nearby the intersection. The rutting depth (RD) is mostly lessthan25mm, and the distribution of RD meets the normal distribution. Theevolution of rutting can be roughly divided into three stages: compaction,plastic flow and failure of structure. The vehicle speed, temperature,aggregates and asphalt are the important factors for the evolution ofrutting.(2)The vehicle speed, axle load, the modulus of pavement and basecourse, as well as the compaction degree of subgrade have a remarkableimpact on the dynamic response of asphalt pavement in the urban road.The slower the vehicle speed is and the greater the axle load is, the worsethe asphalt pavement is. However, with the increase of the modulus of pavement and base course and the compaction degree of subgrade, theresidual deformation of the asphalt pavement becomes smaller.(3) The results of numerical simulation show that the front and reararea of vehicle track are in tensile state, while the centre of vehicle trackis in compressive and shear state. Long term action of the residual stresson the asphalt pavement results in the cumulative of the residualdeformation—that is the rutting. The predictions of the rutting cancapture the observed trend of the actual survey in the urban road. Someempirical formulas are presented by nonlinear fit of the predicted resultsof FEA. According to these formulas, the rutting in the asphalt pavementwill be notable when the cyclic number of traffic loads is more than onemillion.(4)The reinforced pavement can resist the rutting effectively. Thevertical and horizontal deformation of pavement become small due to thereinforced materials embedded in the pavement. The effect of anti-ruttingis more significant when the position of the reinforced materials is closerto the pavement surface, It is advantageous to resist the rutting when themodulus of the surface layer is higher. Some comparisons have beenmade among the three kinds of the asphalt pavement. The results showthat compared with the semi-rigid base pavement and the compoundedbase pavement, the full depth asphalt pavement is advantageous to resistthe rutting.