Characterization of the development of microstructure and porosity of cement-based materials by numerical simulation and ESEM image analysis

This paper describes the characterization of the development of the microstructure and porosity of cement-based materials simulated with a numerical model and compares the results with those obtained from environment scanning electron microscopy (ESEM) images. The numerical cement hydration model HYMOSTRUC is used to simulate the 3D microstructure of cement paste. The geometrical and topological properties of porous media are derived by applying a serial sectioning algorithm with an overlapping creterion. The stereological estimation of ESEM image is used to characterize the morphological changes of microstructure during the cement hydration process. The characteristic parameters simulated by the model and obtained from experiments are compared to one another. The influence of different w/c ratios,i.e. from 0.3 to 0.6, different finenesses of cement particles, 210 m2/kg, 420 m2/kg and 600 m2/kg, and different lengths of curing period are investigated. The potential application of this simulated 3D microstructure on the transport properties being studied by applying a network permeability model. The capillary transport is considered in this model.