Insights on the representative elementary volume of plain cement paste from a micromechanical perspective

It is crucial to define the representative elementary volume (REV) when the structures and/or properties need to be distinguished across an abundance of scales for a heterogeneous and multiphase material. This paper demonstrates a comprehensive study on the REV of plain cement paste from a micromechanical perspective. To that end, a novel micromechanical modeling framework is implemented in terms of a successive three-dimensional virtual tests, where the side length of the microstructural image is increased from 20 μm to 140 μm with a constant grade of 20 μm. First of all, the robustness of the modeling framework is examined through a systematic parametric analysis. Thereafter, two key micromechanical parameters are taken into account, i.e., the Young's modulus and the tensile strength. The dependence of their values as well as statistics on the modeling size is analyzed. The results suggest that the REV size is 80 μm for the Young's modulus, while it is 140 μm for the tensile strength. That is, 140 μm × 140 μm × 140 μm is more reliable as the REV from a micromechanical perspective in whole. In addition, it is revealed that there is a sound linear correlation between the Young's modulus and the mass density in cement paste, while such a correlation is not observed in the case of the tensile strength.