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Probing pores by stars – An essential module in a porosimetry and permeability estimation methodology of virtual cement paste

P. Stroeven

Faculty of Civil Engineering and Geosciences, Delft University of Technology, the Netherlands

Experimental approaches to permeability assessment are time-consuming and as a consequence expensive. A virtual methodology has therefore been developed that is more economical. Herein, reliability can be guaranteed by unbiased data extraction from the simulated cementitious materials that are of a sufficiently realistic nature. Unfortunately, proper validation of the virtual approach cannot readily be accomplished due to recognized shortcomings of the common experimental approach. To achieve a realistic fresh cement particles dispersion, the discrete element method (DEM) is employed, instead of the in concrete technology popular random sequential addition (RSA) approach. This has direct impact on the pore depercolation process during hydration simulation, and thus on the final outcomes of porosimetry. The unbiased measuring of pore size in the resulting very complex capillary pore network structure is the topic covered in this paper. It is a crucial module in the relevant sequence of modules building up the full methodology. “Probing pores by stars” has probably its roots in spatial statistics. Although unknown in concrete technology, a star volume measuring (SVM) method is employed in experimental life science research and used as starting point for further developments. A brief sketch is presented of the various modules to inform the readers about the full potential of the methodology that ultimately offers estimates on permeability. A short discussion is finally provided on the different methodological routes for permeability estimation on the basis of porosimetry data obtained by probing pores by stars.

Key words: Particle packing, virtual cement, porosimetry, star probing, robotics, permeability, SVM