Modified permeability apparatus to determine the permeability of natural building stones

Natural building stones are commonly used for a broad variety of purposes in the construction of many different types of buildings. Knowledge of the permeability of natural building stones, which are widely used in interiors, exteriors, flooring, veneering, landscaping, and walkway laying, is important for correctly determining their lifetime as well as their areas of use. The current study proposes a new test method to determine the air permeability of natural building stones, based on a previously developed method used to assess the permeability values of concrete samples. In this context, the air permeability index values of 96 natural building stone samples, belonging to 16 different types of natural stones classified into five groups, were determined using a new air permeability testing apparatus. The obtained permeability values were compared with the water absorption, open porosity, and apparent density properties of the natural building stones. Strong correlations were identified between the air permeability values of natural building stones and the open porosity and water absorption values. In contrast to other types of tests, the designed apparatus allowed information to be obtained concerning the porosity of natural building stones within a time period as short as 6 h. Based on the obtained results, the air permeability values of the natural building stones were classified into three groups as permeable, semi-permeable, and non-permeable. The study results indicated that the air permeability index can be effectively used to measure the air permeability of natural building stones within a short a period of time and by using a simple test apparatus.