Geotextile characterization and pore-size distribution: Part II. A review of test methods and results

Six of the most commonly used methods for evaluating the pore-size distribution of geotextiles in the United States and Europe are reviewed: dry sieving, hydrodynamic sieving, wet sieving, bubble point method, mercury intrusion porosimetry, and image analysis. In this study, these methods were used to evaluate pore-size distribution characteristics of over 580 specimens from 28 different geotextiles. The results are presented in this paper. In general, the sieving and image analysis techniques required greater amounts of time to perform than the bubble point and mercury intrusion porosimetry tests. The bubble point and mercury intrusion porosimetry tests required extensive preliminary study of testing parameters and test equipment, however, they were fairly simple and rapid to perform. Typical results are given for each method and confirm that there are fundamental differences between the methods. Before any test method is used and applied to the design of geotextiles as filters, it is imperative that the mechanisms of the test and the factors which may influence the test results are understood.