Effects of polydispersity and disorder on the mechanical properties of hydrated silicate gels
Effects of polydispersity and disorder on the mechanical properties of hydrated silicate gels
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DOI：
10.1016/j.jmps.2018.10.003
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发表时间：
2019-01
影响因子：
5.3
通讯作者：
Han Liu;Shiqi Dong;Longwen Tang;N. Krishnan;G. Sant;M. Bauchy
中科院分区：
文献类型：
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作者：
Han Liu;Shiqi Dong;Longwen Tang;N. Krishnan;G. Sant;M. Bauchy
胶态水化硅酸钙（C-S-H）凝胶在很大程度上控制着混凝土的强度。然而，很少有人知道C-S-H凝胶的结构特征如何控制其机械性能。在这里，基于粗粒度的介观模拟，我们研究了颗粒多分散性和结构无序对C-S-H纳米力学的影响。我们的模拟提供了一个很好的协议与纳米压痕数据在很大范围内的堆积密度值。我们表明，在恒定的堆积密度，刚度和硬度不受晶粒尺寸的多分散性。相比之下，无序的水平被发现发挥关键作用。我们表明，在有序的C-S-H模型的情况下，无序的C-S-H凝胶的弹性响应是由其结构内的应力不均匀性和纳米屈服的存在。这些结果突出了C-S-H的内在无序性质以及有序和无序在控制凝胶力学性能中的关键作用。
The colloidal calcium–silicate–hydrate (C–S–H) gel largely controls the strength of concrete. However, little remains known about how the structural features of the C–S–H gel control its mechanical properties. Here, based on coarse-grained mesoscale simulations, we investigate the effect of grain polydispersity and structural disorder on the nanomechanics of C–S–H. Our simulations offer a good agreement with nanoindentation data over a large range of packing density values. We show that, at constant packing density, stiffness and hardness are not affected by the polydispersity in grain sizes. In contrast, the level of disorder is found to play a critical role. We demonstrate that, in contrast to the case of ordered C–S–H models, the elastic response of disordered C–S–H gels is governed by the existence of stress heterogeneity and nanoyielding within its structure. These results highlight the intrinsically disordered nature of C–S–H and the crucial role of order and disorder in controlling gels’ mechanical properties.