Discrete Element Method Simulation Of Rutting Deformation Of Asphalt Mixture

Asphalt pavements have been widely used for road construction due to their good service performance. With rapidly increasing volume of transport, a variety of diseases, such as rutting, appear. It becomes very important and urgent for pavement maintenance to improve the pavement rutting resistance. Therefore, it is significant to study the mechanisms and influence factors of pavement rutting deformation.With combination of experiments and discrete element numerical simulations, the pavement rutting deformation under different conditions was analyzed and the relationships between rutting deformation and different factors, including aggregate gradation, applied load, ambient temperature, were summarized. The main work is as follows:(1) The standard rutting tests were peformanced for the two types of aggregate gradation. The test parameters were achieved by comparing the experiments and numerical simulations.(2) Numerical models of asphalt mixture rutting specimen were established by using the random aggregate generation method. The virtual rutting tests were conducted on them under different loads and external temperatures. The results showed that whether discontinuous gradation or continuous gradation, the larger maximum nominal diameter is, the smaller the rutting deformation is; the bigger the load is, the greater the rutting deformation is; and the higher the temperature is, the bigger the rutting deformation is.(3) Using the virtual unconfined compressive strength test and the virtual splitting test, the shear coefficient(cohesive force and internal friction angle) was achieved. It can be used to evaluate the rutting resistance under different temperatures. The results showed that the bigger shear coefficient is, the better the anti-rutting performance is, and the smaller the rutting deformation is.(4) The rutting deformation laws for varied load and temperature were discussed. For different average loads, the rutting is greater when the load changes from small to big with comparison to the case when load changes from big to small. But for the same average load, the two cases have very close rutting deformations. Although the deformation processes are different when temperature changes from low to high or from high to low, their total deformations are approximate.