Water transport properties of virtual fractal porous media: Implications for the unsaturated transport properties of cement-based materials

Cement-based materials are more and more recognized as fractal materials. From a practical point of view, fractality means that the pore size distribution can be described using fractal scaling law (i.e. power functions). Here, the simplest scaling law making use of a single fractal dimension was used to generate simple and virtual fractal porous media (based on bundles of parallel cylindrical pores). The capillary curve and permeability (relative and intrinsic) of the virtual porous media were then estimated through theoretical and numerical approaches. The results show that: (1) although bereft of any physical basis, van Genuchten equation bears some fractal information; (2) although highly flexible, van Genuchten equation fails to perfectly fit the capillary curves and can thus generate error in inverse analysis (for intrinsic permeability evaluation) and (3) there seems to be a relation between the intrinsic permeability and van Genuchten pressure parameter.

Automated summary

Cement-based materials are increasingly recognized as fractal materials, with fractal scaling laws used to describe the pore size distribution. This study generated virtual fractal porous media based on bundles of parallel cylindrical pores, and estimated their capillary curve and permeability using theoretical and numerical approaches. The results suggest that the van Genuchten equation, although lacking a physical basis, contains fractal information, but may not perfectly fit capillary curves and could introduce errors in inverse analysis. Additionally, there appears to be a relationship between intrinsic permeability and the van Genuchten pressure parameter.