This standard (Part 3) specifies laboratory methods for determining the water permeability of a single layer of geotextile normal to its plane, under no compressive load. It covers procedures for both the constant head method, suitable for materials with higher permeability, and the falling head method for materials with lower permeability.
Specifies methods for determining hydraulic properties of geotextiles such as permeability, permittivity and apparent opening size.
Quick Reference Values
Test specimen dimensions100 mm x 200 mm
Initial slit length15 mm
Rate of jaw separation (CRE)300 ± 10 mm/min
Pre-tension for specimens ≤ 200 g/m²1 N
Pre-tension for specimens > 200 g/m²2 N
Number of specimens per directionMinimum 5
Key Formulas
Tear Strength (N) = Average of the five highest peak forces recorded during the test for each specimen.
Practical Notes
Ensure the specimen is clamped perfectly along the non-parallel sides of the trapezoid to ensure force is applied correctly.
The test result is an average of the five highest peaks from the force-elongation curve, not just the single maximum peak.
This test is critical for applications where the geotextile might be subjected to puncture and subsequent tearing, such as under sharp aggregate.