This paper presented a new field method for measuring the depth of the vaporization plane below surface of porous materials. The measuring device consisting of a rod, adhesive, and a water-soluble dye is placed into a porous material. As the pore water dissolves the dye, thus changing the device’s appearance, the dry and wet zones inside of the material can be visually distinguished. The suggested method is minimally destructive as it can be used in holes as small as 2 mm in diameter, relatively fast (typical measurement takes 10 min), and cost-effective compared to other available methods. We have conducted >500 measurements on a range of compact materials (sandstone, arkose, tuff, rhyolite), mostly on natural outcrops in humid continental, warm and cold semi-arid, and desert climates. It has been also shown that the method can find use in studying water presence in building materials or soil. We believe the method will give the scientific community a whole new perspective of water distribution especially in the near sub-surface of porous rocks for studying salt and cavernous weathering, lithophilic organisms, or water dynamics in both natural and artificial porous materials.

Weiss T., Mareš J., Slavík M., Bruthans J. (2020): A microdestructive method using dye-coated-probe to visualize capillary, diffusion and evaporation zones in porous materials. Science of The Total Environment 704, 135339 (DOI)