Wang Hui, Mang Herbert, Yuan Yong, Pichler Bernhard L A
College of Civil Engineering, Tongji University, Shanghai 200092, China.
Institute for Mechanics of Materials and Structures, TU Wien-Vienna University of Technology, Karlsplatz 13/202, 1040 Vienna, Austria.
Materials (Basel). 2019 Aug 22;12(17):2689. doi: 10.3390/ma12172689.
The thermal expansion coefficient and the microscopic thermal stresses of mature concrete depend on its microstructural composition and the internal relative humidity. This dependence is determined by means of thermoelastic multiscale analysis of concrete. The underlying multiscale model enables two types of scale transition. Firstly, bottom-up homogenization allows for the quantification of the thermal expansion coefficient and the elastic stiffness of concrete based on the Mori-Tanaka scheme. Secondly, top-down scale concentration gives access to the volume averaged stresses experienced by the cement paste, the fine and the coarse aggregates and, furthermore, to the stress states of the interfacial transition zones covering the aggregates. The proposed model is validated by comparing the predicted thermal expansion coefficient of concrete with independent sets of experimental measurements. Finally, sensitivity analyses are carried out to evaluate the influence of the volumetric composition and the internal relative humidity of concrete on the thermal expansion coefficient and the microscopic thermal stresses.
成熟混凝土的热膨胀系数和微观热应力取决于其微观结构组成和内部相对湿度。这种依赖性通过混凝土的热弹性多尺度分析来确定。基础多尺度模型实现了两种类型的尺度转换。首先，自下而上的均匀化允许基于森田方案对混凝土的热膨胀系数和弹性刚度进行量化。其次，自上而下的尺度浓缩可以获取水泥浆体、细骨料和粗骨料所经历的体积平均应力，此外，还可以获取覆盖骨料的界面过渡区的应力状态。通过将预测的混凝土热膨胀系数与独立的实验测量数据集进行比较，对所提出的模型进行了验证。最后，进行敏感性分析以评估混凝土的体积组成和内部相对湿度对热膨胀系数和微观热应力的影响。
