Issues on characterization of cement paste microstructures from μ-CT and virtual experiment framework for evaluating mechanical properties

There are issues on the microstructure characterization of cement paste obtained from μ-CT due to resolution limits, and evaluation of properties through virtual experiments. A phase separation procedure between the solid and pore phases, which can be used for pure cement paste microstructures, is proposed. The problems of underestimation of microstructural characteristics such as porosity in virtual specimens from μ-CT, as compared to real specimens, are addressed. Reflecting such underestimation, the process of input modeling parameter determination for virtual experiments on mechanical property evaluation using the phase field fracture model is elaborated. Through virtual tests, the effects of domain size and mesh resolution on the evaluated properties are investigated, and the correlation between the microstructural characterization parameters and mechanical properties is reconfirmed. It is shown that the virtual experiment framework proposed in this study can be used as a loading tool to supplement time and effort consuming real experiments for evaluating the mechanical properties of cement paste at the micro-scale.