Abstract Quasi-instantaneous thermal expansion of cement pastes is governed by the relative humidity (RH) within their air-filled pores and by the decrease/increase of this internal RH resulting from a temperature decrease/increase. The latter effect is traced back to quasi-instantaneous water uptake/release by cement hydrates, using microporomechanics and a three-scale representation of mature cement pastes. Partially saturated gel and capillary pores are considered to be connected and spherical, with radii following exponential distributions. The Mori-Tanaka scheme provides the scale transition from effective pore pressures to eigenstrains at the cement paste level. This modeling approach, together with considering mass conservation of water, allows for downscaling macroscopic thermal expansion coefficients, so as to identify the molecular water uptake/release characteristics of the hydrates. The latter characteristics are mixture-independent, as shown by their use for predicting the thermal expansion coefficients of different mature cement pastes, with w/c-ratios ranging from 0.50 to 0.70.

中文翻译：

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水合物的可逆吸水/放水可以解释水泥浆的热膨胀吗？— 来自逆多尺度分析的参数

摘要 水泥浆体的准瞬时热膨胀受其充满空气的孔隙内的相对湿度 (RH) 以及由于温度降低/增加而导致的内部 RH 的减少/增加的控制。后一种效应可以追溯到水泥水合物的准瞬时吸水/释放，使用微孔力学和成熟水泥浆的三尺度表示。部分饱和的凝胶和毛细孔被认为是连通的和球形的，半径服从指数分布。Mori-Tanaka 方案提供了从有效孔隙压力到水泥浆水平的本征应变的尺度转换。这种建模方法，连同考虑水的质量守恒，允许缩小宏观热膨胀系数，从而确定水合物的分子水吸收/释放特性。后一特性与混合物无关，如它们用于预测不同成熟水泥浆体的热膨胀系数所示，w/c 比范围为 0.50 至 0.70。