Overview
ISO 10722:2019 - Geosynthetics: Index test procedure for the evaluation of mechanical damage under repeated loading (damage caused by granular material) is a laboratory test method that simulates dynamic, granular-material-induced mechanical damage to geosynthetics. The standard defines an index test procedure to assess damage visually and by measuring loss of tensile strength, using a defined standard granular material. It is explicitly not intended to be used to derive reduction factors for geosynthetic reinforcement.
Key topics
- Test principle: A geosynthetic specimen is sandwiched between two layers of granular material and subjected to cyclic loading; damage is evaluated visually and by change in a reference mechanical property.
- Specimen preparation: Follow ISO 9862 sampling; prepare at least five wide specimens (cut from 2.0 m × 0.20 m minimum), then split into paired damaged and reference specimens for tensile testing.
- Loading parameters: Cyclic sinusoidal pressure between (10 ± 1) kPa and (500 ± 10) kPa at 1 Hz for 200 cycles, applied via a loading plate (100 × 200 mm).
- Apparatus & container: Rigid metal box (minimum 300 × 300 mm plan, two 75 mm deep parts), shims to avoid pre-tension, and a compression machine capable of required pressures.
- Standard granular material: Sintered aluminium oxide with particle-size limits - 100% passing 10 mm sieve and 0% passing 5 mm sieve (EN 933-1). Material reuse limits and wet sieving requirements are specified.
- Conditioning: Tests in the standard atmosphere per ISO 554 (20 ± 2 °C; 65 ± 5% RH).
- Assessment & calculations: Change in reference property expressed as percentage retained value; visual record of holes and qualitative damage; results reported with statistics and test conditions.
Applications
ISO 10722:2019 is used by:
- Geotechnical engineers assessing the vulnerability of geosynthetics (geomembranes, geotextiles, geogrids) to mechanical damage from granular backfill under dynamic loads.
- Manufacturers and QA labs for comparative index testing, quality control, and product development.
- Specifiers and consultants requiring an objective lab method to compare resistance to repeated loading and granular abrasion.
Practical use cases include evaluation before using geosynthetic reinforcement in road bases, embankments, aggregate layers, and temporary works where repeated loading from traffic or construction equipment occurs.
Related standards
- ISO 10319 - Wide‑width tensile test (common reference test for tensile strength)
- ISO 9862 - Sampling and specimen preparation for geosynthetics
- EN 933‑1 - Particle size distribution (sieving)
- ISO 554 - Standard atmospheres for conditioning
- ISO 11461 - Soil water content (referenced if Annex A soil variants used)
Keywords: ISO 10722:2019, geosynthetics, mechanical damage, index test procedure, repeated loading, granular material, tensile strength, laboratory test method.
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