沥青混合料集料结构的细观力学性能及级配优化

Chen Jingchun, Wang Jian, Li Min, Zhao Zedong, Ren Jiaolong

School of Civil Engineering and Geomatics, Shandong University of Technology, Zibo 255000, China.

School of Transportation and Vehicle Engineering, Shandong University of Technology, Zibo 255000, China.

Materials (Basel). 2023 Jun 29;16(13):4709. doi: 10.3390/ma16134709.

Particle media are widely used in engineering and greatly influence the performance of engineering materials. Asphalt mixtures are multi-phase composite materials, of which coarse aggregates account for more than 60%. These coarse aggregates form a stable structure to transfer and disperse traffic loads. Therefore, knowing how to adjust the structural composition of coarse aggregates to optimize their performance is the key to optimize the performance of asphalt mixtures. In this study, the effects of different roughness and different sizes on the interlocking force and contact force of coarse aggregates were investigated through means of simulation (DEM), and then the formation-evolution mechanism of the coarse aggregate structure and the role of different sizes of aggregates in the coarse aggregate structure were analyzed. Subsequently, the optimal ratio of coarse aggregates was explored through indoor tests, and finally, the gradation of asphalt mixture based on the optimization of fine structure was formed and verified through indoor tests. The results showed that the major model can effectively reveal the role of different types of aggregates in the fine structure and the relationship between the strength of contact forces between them and clarify that the strength of the fine structure increases with the increase in aggregate roughness. Hence, the coarse aggregate structure can be regarded as a contact force transmission system composed of some strong and sub-strong contact forces. Their formation-evolution mechanism can be regarded as a process of the formation of strong and sub-strong contact forces and the transformation from sub-strong contact force to strong contact force. Moreover, the dynamic stability of the optimized graded asphalt mixture was increased by 30%, and the fracture toughness was increased by 26%.

颗粒介质在工程中广泛应用，并对工程材料的性能有很大影响。沥青混合料是多相复合材料，其中粗集料占比超过60%。这些粗集料形成稳定结构以传递和分散交通荷载。因此，了解如何调整粗集料的结构组成以优化其性能是优化沥青混合料性能的关键。在本研究中，通过模拟（离散元法）研究了不同粗糙度和不同粒径对粗集料联锁力和接触力的影响，然后分析了粗集料结构的形成演化机理以及不同粒径集料在粗集料结构中的作用。随后，通过室内试验探索了粗集料的最佳比例，最后，基于细观结构优化形成了沥青混合料级配，并通过室内试验进行了验证。结果表明，主要模型能够有效揭示不同类型集料在细观结构中的作用以及它们之间接触力强度的关系，并阐明细观结构强度随集料粗糙度的增加而增加。因此，粗集料结构可视为由一些强接触力和次强接触力组成的接触力传递系统。它们的形成演化机理可视为强接触力和次强接触力形成以及次强接触力向强接触力转变的过程。此外，优化级配沥青混合料的动稳定度提高了30%，断裂韧性提高了26%。