Filtration Opening Size of Geotextiles by Hydrodynamic Sieving
The latest development on the hydrodynamic sieving technique (HST) using glass beads to determine the filtration opening size (FOS) of geotextiles is presented. The FOS value is defined as the 95% (by mass) diameter of the glass beads which have passed through the geotextile under the hydrodynamic sieving action. The data of an experimental program to verify the repeatability and reproducibility are reported and discussed. The technique was found to be simple and repeatable for all types of geotextiles. The FOS of geotextiles measured by the HST is related to the geotextiles´ general parameters such as their mass per unit area and thickness. The FOS value can be roughly estimated from simple knowledge of these parameters using the relationship established for the type of product.