Porosity and Wear Resistance in Stone Flooring Tiles

A sorptivity test and a permeability test were used as an assessment of the degree of porosity of stone flooring tiles, where there was particular interest in the surface characteristics. A good correlation was obtained between the two tests; the sorptivity is preferred since it is the easier to perform and could be extended to assess the characteristics of full-sized tiles. A Taber Abraser was used to compare the likely wear of the stones. Assessment was by weight loss and by groove depth, measured by both a depth micrometer and a laser beam profile meter. Good agreement was achieved among all the wear measurement methods. The laser beam is the least preferred method due to the equipment cost and availability. Mohs' mineralogical scratch method was used to assess hardness, which is possibly related logarithmically to the Taber wear. The stone types were two granites and two marbles in common use in Hong Kong. One granite had the best properties from all measurements. The other granite and one of the marbles had similar properties, while the remaining marble showed distinctly inferior properties. Flooring specification limits could perhaps be set above those achieved on the poorer marble, but more work is required to set definitive limits. Stone flooring physical property limits do not appear to be specified in Hong Kong, and elsewhere performance specifications seem to be at best limited.