Microstructure characterization of cement paste from micro-CT and correlations with mechanical properties evaluated from virtual and real experiments

Highlights: • The properties of cement paste are correlated with the microstructural characteristics obtained from micro-CT. • The cement paste microstructure is idealized as two-phase (pore/solid) material. • The micro-scale cement paste mechanical properties and porosity from the micro-CT images are correlated. • The solid phase properties are correlated with the mean linear attenuation coefficient (LAC) from the micro-CT images. -- Abstract: As micro-CT devices have become widely available, the detailed 3D microstructures of cementitious materials can be more conveniently investigated. However, owing to the resolution required to appropriately represent the cement-paste microstructures, the domain size of the micro-CT sample is limited. By synergistically combining the virtual and real experiments, correlations between the microstructural characteristics and properties of cement paste with various w/c ratios (0.3, 0.4, 0.5, and 0.6) are investigated at different length scales. The porosity from the micro-CT images are correlated with the macro-scale properties obtained from real experiments. At the micro-scale, the homogenized solid phase properties are characterized from the linear attenuation coefficient (LAC) value distribution characteristic of the micro-CT images and are correlated with the modeling parameters of the phase field fracture. According to the results of virtual experiments conducted using the phase field fracture model and the characterization methods, the mechanical properties (stiffness/strength) at the micro- and macro-scale exhibited apparent relationships.