Application of the Bubble Point Method to the Characterization of the Pore-Size Distribution of Geotextiles
For the design of a geotextile as a filter, reliable information about the pore-size distribution of the geotextile is needed. The bubble point method is one technique that is able to provide this information for a geotextile. The bubble point method is a simple and rapid technique for evaluating pore-size distributions of virgin, clogged, and stretched geotextiles. In addition, the bubble point equipment is also capable of providing information as to the degree of clogging within a geotextile and the permeability of a geotextile. The geotextile pore-size distribution results obtained by the bubble point method showed good repeatability. However, the bubble point method was only able to distinguish between geotextiles that had significantly different cross sections. Pore-size distribution results for geotextiles with similar cross sections, but of increasing thickness, were very similar. The dry sieving (ASTM D 4751), hydrodynamic sieving (CAN/CGSB-148.1-10), AND WET SIEVING (sw-640550-83) METHODS ARE GENERALLY only useful for evaluating the larger pore openings (O95, O90) of the geotextiles. In addition, the methods are time consuming. The mercury intrusion porosimetry method (ASTM D 4404) was also performed; however, there was little difference in pore-size distribution results for any of the 28 different geotextiles tested (Smith 1993). There are also environmental concerns with using mercury. The bubble point method showed potential for characterizing the pore-size distribution of geotextiles.