This Indian Standard (Part 2) specifies the method for determining the thickness of geotextiles and related products at a specified pressure. It details the testing apparatus, specimen preparation, procedure, and calculation method. This test is a fundamental physical property measurement for quality control and design input.
Specifies methods for determining physical properties of geotextiles such as mass per unit area and thickness.
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.