This paper presents a method to numerically investigate the microstructural effect on the creep behavior of cement paste at the microscale. The lattice fracture model is extended to consider local time-dependent deformations of calcium-silicate-hydrate phases in the cement paste by imposing local forces. The term “experimentally informed model” is used herein as the heterogeneous microstructures of hardened cement pastes were obtained by using the X-ray computed microtomography and directly implemented into the model. The mechanical and creep properties of different constituents at the resolution of 5 µm were inversely identified from the fracture and creep bending tests on cementitious microcantilever beams at the microscale. The model is then validated through the comparison with the testing results of cement pastes with different w/c ratios and microstructures. It is found that the developed model can successfully reproduce experimentally observed behaviors and be applied to explain the experimental results in detail. With the method presented in this paper, the relationship between the volume fractions of different components and the global creep behavior of cement paste can be established. The validation of the model performed at the microscale forms a basis for the multiscale analysis of concrete creep.

中文翻译：

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使用实验知会的晶格模型对硬化水泥浆的蠕变的微观结构影响进行建模

本文提出了一种在微观尺度上数值研究微观结构对水泥浆蠕变行为的影响的方法。扩展了晶格断裂模型，以考虑通过施加局部力使水泥浆中硅酸钙水合物相随时间的局部变形。本文中使用术语“实验知悉模型”，因为硬化的水泥浆的异质微观结构是通过使用X射线计算机显微断层照相术获得的，并直接实现到模型中。从微观尺度上的水泥微悬臂梁的断裂和蠕变弯曲测试，可以反向确定分辨率为5 µm时不同成分的机械性能和蠕变性能。然后通过与不同水泥浆的测试结果进行比较来验证该模型w / c比和微观结构。发现所开发的模型可以成功地再现实验观察到的行为，并可以用于详细解释实验结果。利用本文提出的方法，可以建立不同组分的体积分数与水泥浆整体蠕变行为之间的关系。在微观尺度上进行的模型验证为混凝土蠕变的多尺度分析奠定了基础。