There are many test methods available to determine the pore sizes of geotextile filters. Often overlooked is the fact that each method provides a different interpretation of a geotextile's pore structure. A survey of the available test methods, indicates that four categories of pores can be measured. Pore characteristics are identified by one of the following methodologies: sieving, theoretical, volumetric, and numerical. A critical review of the data produced by these methods shows that the actual pore structure as related to flow-through behavior can only be determined by the bubble point method, which provides a volumetric pore size. This test identifies the constriction size of each pore channel in a geotextile, where retention and clogging are most critical. The bubble point test method is advantageous because it provides for the complete pore size distribution of the geotextile, can be performed more efficiently than sieving methods, and provides an accurate estimate of the permeability of the geotextile.
Geotextiles are widely used in filtration applications. For continued growth in this area, it is critical that geotextiles be properly designed for these applications to prevent failures. The geotextile property that is most directly related to the design of a geotextile as a filter is the pore-size distribution of the geotextile. The main objective of this study was to compare the performance of the following six different test methods to evaluate the pore-size distribution of geotextiles: dry sieving, hydrodynamic sieving, wet sieving, bubble point method, mercury intrusion porosimetry, and image analysis. Twenty-eight geotextiles from five different manufacturers were evaluated. In this paper, the pore-size distribution results obtained from these methods are compared. The differences in pore opening results by different methods are illustrated using a design example.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.