13th International Conference on Fracture June 16–21, 2013, Beijing, China -1- Simulation of Damage and Crack Propagation in Three-Point Bending Asphalt Concrete Beam Guowei Zeng1,2,*, Xinhua Yang1, Fan Bai1 Anyi Yin1 1 School of Civil Engineering and Mechanics, Huazhong University of Science and Technology, 430074, China 2 Hubei Province Key Laboratory of Systems Science in Metallurgical Process, Wuhan University of Science and Technology, 430065, China * Corresponding author: zengguow@126.com Abstract A brittle damage-based constitutive model is proposed to characterize the crack initiation and propagation behavior of asphalt mastic under low temperature. The fracture criterion is regarded as a dominant of damage. For asphalt concrete combining aggregate and asphalt mastic, a 2D finite element model including the aggregate generation and packing algorithm and Usermat subroutine technique is developed to perform the crack initiation and propagation. A series of FE simulations are performed to evaluate effects of crack location on crack propagation of asphalt concrete. The numerical results are validated by comparison with the corresponding experiments and other result which based on fracture criterion of maximum circumferential tensile stress. The model and method are proved to be rational and capable of describing the cracking behavior of asphalt concrete with different crack location. Keywords Asphalt concrete, Three-Point Bending Beam, Numerical Simulation, Brittle Damage, Crack 1. Introduction Crack is the one of most common distresses of asphalt materials and reduces the road service capacity. Furthermore it also allow for the infiltration of moisture, which result in a rapid deterioration of the pavement structure. It can be suggested that heterogeneity of composites affected its fracture behavior and leading to a significant complexity in crack propagation analysis [1]. The mechanism of crack growth and evaluation of the characterization of fractured pavement structure generally are the fundamental problems in the pavement engineering. They have been more widely focused and studied by the researchers and engineers in recently years [2-5]. The fracture resistance of asphalt concrete significantly influences the service life of asphalt pavements and consequently the maintenance of the pavement network. Numerous researchers [6-8] proved that the mechanical properties of asphalt concrete are significantly affected by micro structural details and some material parameters, including asphalt content, aggregate type, gradation of aggregate particles, distribution and orientation of aggregates, void ratio, and so on. According to combination of the micromechanical properties of asphalt concrete and heterogeneity, the mechanism cracking behavior for asphalt concrete can be simulated more accurately by construct the micromechanical model containing information about its components and microstructures. For this aim, the current study presents an approach based on the CDM, which considers the concrete heterogeneity. Asphalt concrete can be described as a multiphase material containing coarse aggregates, mastic cement(including asphalt binder and fine aggregates), and air voids. In this method, the numerical sample model is constructed by replacing the irregular aggregate geometry to resemble real polygon, circle, elliptical and so on. The aggregate content, gradation and some structural parameters, aggregates are generated and randomly located in a prescribed region. Then the generations are assigned to coarse aggregates and the rest region to the mastic. With this method the mechanical properties and fracture of asphalt concrete were evaluated by Xu et al. in[9], Yang et al. in[10] and Yin et al. in[11, 12]. Especially Yin et al. [11, 12] successfully applied the numerical sample model method to investigate the gestation and propagation of the crack in two-dimensional models including three-point bending asphalt mixture beam with pre-crack and uniaxial tensile
RkJQdWJsaXNoZXIy MjM0NDE=