Abstract In the present contribution, the effective mechanical, diffusive, and chemo-expansive properties of concrete are computed from a multi-scale and multi-physics approach. The distinctive features of the approach are that i) the mechanical and diffusive responses are modelled in a coupled fashion (instead of separately, as is usually done), and that ii) the multi-scale model considers three different scales of observation, which allows for including heterogeneous effects from both the micro- and meso-scales in the effective macro-scale properties of concrete. At the macro-scale, the concrete material is considered as homogeneous, whereas at the meso-scale it consists of particle aggregates embedded in a porous cement paste. At the micro-scale the porous cement paste is described as a two-phase material, composed of a solid cement phase and saturated capillary pores. Adopting a two-level asymptotic homogenization procedure, the effective meso-scale properties of the porous cement paste are computed first, using a unit cell that includes the cement paste and pore characteristics. Subsequently, the obtained meso-scale response of the porous cement paste, together with the aggregate characteristics, defines the material properties of a second unit cell, which is used for calculating the effective macro-scale response of concrete. The distributions of the pores and the aggregates within the unit cells are determined from a uniform, random distribution of points, and their radii are defined from a probability distribution function. The efficacy of the proposed framework is illustrated by studying the effective mesoscopic response of a porous cement paste, which demonstrates the influence of the micro-scale porosity and pore percolation. Next, the effective macroscopic response of concrete is analysed, by considering the influence of the aggregate volume fraction, the mismatches in elastic stiffnesses and diffusivity between the aggregate and the cement paste, and the porosity. The computed effective properties are compared with experimental data from the literature, showing a good agreement.

中文翻译：

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通过渐近均质化多尺度预测混凝土材料的化学力学性能

摘要 在目前的贡献中，混凝土的有效力学、扩散和化学膨胀性能是通过多尺度和多物理方法计算的。该方法的显着特点是 i) 机械和扩散响应以耦合方式建模（而不是像通常那样单独进行），以及 ii) 多尺度模型考虑三个不同的观察尺度，这允许包括微观和中观尺度的异质效应对混凝土的有效宏观尺度特性。在宏观尺度上，混凝土材料被认为是均质的，而在中尺度上，它由嵌入多孔水泥浆中的颗粒集料组成。在微观尺度上，多孔水泥浆被描述为两相材料，由固体胶结相和饱和毛细孔组成。采用两级渐近均质化程序，首先使用包含水泥浆和孔隙特征的晶胞计算多孔水泥浆的有效细观尺度特性。随后，获得的多孔水泥浆体的中尺度响应与骨料特性一起定义了第二个晶胞的材料特性，用于计算混凝土的有效宏观响应。晶胞内孔和聚集体的分布由均匀、随机的点分布确定，其半径由概率分布函数定义。通过研究多孔水泥浆体的有效细观响应来说明所提出框架的功效，这证明了微孔率和孔隙渗流的影响。接下来，通过考虑骨料体积分数、骨料与水泥浆之间弹性刚度和扩散率的不匹配以及孔隙率的影响，分析混凝土的有效宏观响应。计算出的有效性能与文献中的实验数据进行了比较，显示出良好的一致性。骨料和水泥浆之间的弹性刚度和扩散率不匹配，以及孔隙率。计算出的有效性能与文献中的实验数据进行了比较，显示出良好的一致性。骨料和水泥浆之间的弹性刚度和扩散率不匹配，以及孔隙率。计算出的有效性能与文献中的实验数据进行了比较，显示出良好的一致性。