基于离散单元法的环氧沥青混凝土虚拟断裂试验研究

Experimental study on virtual fracture of epoxy asphalt concrete based on discrete element method

为明晰环氧沥青混凝土的断裂力学行为特征,基于数字图像处理技术,采用离散元方法建立了切口小梁二维模型,开展了环氧沥青混凝土的虚拟弯曲断裂试验.从细观角度分析了环氧沥青混凝土断裂过程中的力学响应,探讨了其断裂机理及裂纹扩展路径,并与室内试验结果进行了对比.结果表明,采用离散元方法可较好地反映环氧沥青混凝土的断裂力学特性,数值模拟过程中虚拟试件的力学响应与理论结果相符.虚拟试验获取的材料强度参数与室内试验的测试结果接近,误差仅为0.25%,但前者所得的劲度模量因破坏挠度偏大,较后者低16.56%.在裂纹扩展过程中,破坏易产生于黏结较为薄弱的集料-砂浆界面.虚拟试验与室内试验的对比分析结果验证了离散元模型以及参数取值的正确性.

In order to clarify the fracture mechanical behaviors of epoxy asphalt concrete （ EAC）, a single-notched beam two-dimensional model was established by the discrete element method based on digital image processing technology. The virtual bending fracture tests of EAC were performed to stud- y the mechanical response in the fracture process of EAC under meso-scale. The fracture mechanism and cracks propagation paths were analyzed and compared with the laboratory test results. The results show that the discrete element method can be used to exhibit the fracture characteristics of EAC ex- cellently. The mechanical responses of the virtual tests obtained by numerical simulation are coinci- dent with the theoretical results. The material strength parameters acquired by the virtual test are close to those of the indoor tests, with an error of 0.25 %. However, the stiffness modulus obtained by the virtual test is 16.56% lower than the test results due to the large deflection. The damage tends to occur in the interface with inferior adhesive performance between the aggregate and asphalt mastic during the cracks propagation. The comparison between the virtual test results and the experimental results verify the availability of the discrete element model and the relevant material parameters.