Overview - EN ISO 25619-1:2021 (Geosynthetics, compressive creep)
EN ISO 25619-1:2021 specifies index test methods to determine the compressive creep properties of geosynthetic products. It describes two laboratory methods: the standard normal compressive loading method and a combined normal-and-shear loading method for products that are shear-sensitive (for example, columnar or cuspated structures). Tests may be performed on dry specimens or on specimens immersed in water; immersion is required when any part of the product contains a hydrophilic polymer.
Key topics and technical requirements
- Scope and purpose: Index test procedures for assessing time-dependent compression (creep) behaviour of geosynthetics under constant compressive stress.
- Two test methods:
- Normal compressive load method (Clause 5) - the standard procedure.
- Combined normal and shear load method (Clause 6) - for products prone to shear failure.
- Specimen preparation:
- Sampling and preparation referenced to ISO 9862.
- Specimens are square, minimum 100 mm × 100 mm; sides aligned with machine direction (MD) and cross‑machine direction (CMD).
- Special rules for products where loading is resisted at defined points, lines or areas (minimum coverage/number of contact lines).
- Thickness and strain definitions:
- Terms such as thickness, initial thickness (under 2 kPa), initial compressed thickness (measured 1 min or 4 min after loading), total compressive strain, and compressive creep strain are defined.
- Test conditions:
- Tests can be conducted dry or immersed in water per ISO 3696 for water quality.
- Conditioning and laboratory atmosphere per ISO 554.
- Reporting and outputs:
- Procedures include apparatus, stepwise test procedure, calculations, typical curves and test report requirements (see Clauses 5–6 and Annex B).
Practical applications and users
Who uses EN ISO 25619-1:2021:
- Geotechnical engineers and designers assessing long‑term deformation of geotextiles, geogrids, geocells and cuspated drainage cores.
- Manufacturers and quality laboratories performing product characterization and type testing.
- Specifiers and contractors preparing performance requirements for landfill liners, drainage composites, reinforcement layers and other civil-engineering systems that incorporate geosynthetics.
Practical value:
- Provides reproducible, comparable compressive creep data for design and specification.
- Identifies behaviour under combined compression and shear for structured products.
- Supports material selection for long‑term performance in applications exposed to sustained loads or wet conditions.
Related standards
- ISO 9862 - Sampling and preparation of test specimens
- ISO 9863-1 - Determination of thickness at specified pressures (single layers)
- ISO 10318-1 - Terms and definitions for geosynthetics
- ISO 554, ISO 3696 - Conditioning and water quality references
Keywords: EN ISO 25619-1:2021, geosynthetics, compressive creep, compression behaviour, test methods, normal compressive loading, shear loading, geotextiles, index test.
