The Discrete Element Method For Performance Evaluation Of Gradation Segregation Of Asphalt Mixture

The segregation of the asphalt mixture leads to the uneven distribution of grains, which results in the deviations in many indexes comparing the design and standard value. As a result of the gradation segregation, there are poor service performance in the permeability, the tensile strength and the modulus of resilience of the asphalt pavement, which accelerates the seriousness of the early damage of the pavement.The indoor and the field test is adopted to study the segregation performance of the asphalt mixture for a long time. But these are disadvantages about traditional methods, for example, there are many influencing factors, the process is complicated and randomness and they cost a lot of manpower and material resources. It is more convenience, shortcut, repeatability and high efficiency when using computer program to simulate the segregation of the asphalt mixture. Once the segregation numerical simulation models are build, lots of data basis can be provided for the performance evaluation of the segregation for the asphalt mixture by simple numerical calculation combining some data from actual test.The segregation numerical simulation program is compiled on the basis of fundamentals of the discrete element method in the C++program language. The program includes two patterns, the model of sphere particles and the model of polyhedron particles. Two structure composition of asphalt mixture are simulated using the numerical simulation program, whose results are compared with the data from the indoor segregation test. The effectiveness of the discrete element program in simulating the segregation is verified. The impact of the shape model of the particles using in the program on the simulation test is discussed. In addition, it is a good reference to the assurance measures of the segregation capability in the process of the grading design and the construction.