Numerical simulation of the compaction process and the layer bonding with the multiscale modeling

重型交通基础设施需要最佳的材料组成、精确的施工工艺和尽可能好的压实，以确保足够的耐久性。在子项目2的第一个应用期的范围内，建立了沥青的细观力学有限元公式，以描述材料组成和各材料组分之间的相互作用。对施工和压实过程中机理的基本了解尚未确定。沥青层之间的粘结是沥青路面耐久性的另一个先决条件。在第一个应用阶段，分项目1和4根据宏观的现象学公式发展了所需的理论和实验基础。应用微观力学方法研究材料各组分之间由于粘结、摩擦和互锁而产生的粘结的基本机制。第一个应用期的结果提供了所有必要的先决条件，即关于沥青压实和层间粘结的基本机制的基本知识可以在微观结构尺度上确定，这一点目前尚不存在。特别是，这指的是对来自分项目2和3的各种沥青的微观结构进行分析的结果。生成的数据是建立微观力学模型的基础。这些模型被用于子项目2，以确定沥青的微结构与抗疲劳和抗变形性能之间的关系。在子项目4和子项目3中建立了试验基地。将微观模型集成到子项目1的宏观连续介质力学有限元模型中，以允许对整个路面上部结构进行分析。在考虑路面特性和底盘参数的情况下，借助子项目1、3和5中的方法来确定交通诱导荷载，可以利用第一个应用期的结果来精确计算交通引起的沥青路面和接缝的机械荷载。在这一点上，加载和损伤过程之间的关系可以用细观机械过程来描述。在第二应用阶段的范围内，将在子项目2中开发微观和细观力学模型，以加强对施工和压实过程中潜在过程的理解，最终通过精确影响沥青微观结构和未来沥青层之间的粘结来优化这些过程。第二个应用阶段的另一个目标是为耦合模型的大规模验证以及将不确定的材料参数从微观转移到宏观尺度建立实验基础。

Heavy duty transportation infrastructure requires optimal material compositions, precise construction processes and the best possible compaction to ensure sufficient durability. In the scope of the first application period for subproject 2 micro mechanical finite elements formulations for asphalt were developed to describe the material composition and the interactions between the respective material components. A fundamental understanding of mechanisms during construction and compaction processes has yet to be determined.The bonding between layers in asphalts is another prerequisite for the durability of asphalt pavements. In the first application period subprojects 1 and 4 developed the required theoretical and experimental fundamentals based on macroscopic, phenomenological formulations. The underlying mechanism of bonding due to adhesion, friction and interlocking between respective components of the material shall be investigated under application of micromechanical approaches.The results from the first application period offer all necessary prerequisites, that fundamental knowledge about the underlying mechanisms of asphalt compaction and layer bonding, that is not currently available, can be determined on a microstructure scale. In particular, this refers to results on the analysis of the microstructure of various asphalts from subprojects 2 and 3. The generated data represents the basis for micromechanical models. These models were used in subproject 2 to determine the relation between the microstructure of asphalt and the resistance against fatigue and deformation. The experimental base was established in subprojects 4 and 3. The micro-model was integrated into the macroscopic continuum mechanical FE-model of subproject 1 to allow for the analysis of entire pavement superstructures. Traffic induced loading was determined with the aid of approaches from subprojects 1, 3 and 5 under consideration of surface characteristics and chassis parameters.Precise calculations of mechanical loading in asphalt pavements and joints due to traffic can be conducted with the results from the first application period. At this point, the relationship between loading and damaging processes can be described with micromechanical processes. In the scope of the second application phase, micro- and meso-mechanical models are to be developed in subproject 2 to enhance the understanding of underlying processes during construction and compaction to ultimately allow for an optimisation of these processes by precisely influencing the asphalt microstructure and the bonding between asphalt layers in the future. Another objective in the second application phase is establishing an experimental base for a large-scale validation of the coupled models as well as transferring the uncertain material parameters from the micro into the macro scale.