ISO 25619-2:2015

Overview

ISO 25619-2:2015 - "Geosynthetics - Determination of compression behaviour - Part 2: Determination of short‑term compression behaviour" defines an index test method to measure the short‑term compressive behaviour of geosynthetics. The standard describes test setup, specimen preparation, conditioning, test procedure and calculations to report short‑term compressive strength and corresponding compressive strain (or strain at 1 MPa). It is intended for quality control and material characterization, not for structural design.

Key topics and requirements

• Test principle: Apply a uniaxial compressive load perpendicular to major specimen faces while recording force and displacement to produce a stress–strain curve.
• Apparatus:
  • Compression testing machine conforming to ISO 7500-1 (Class 2 or higher) with rigid, parallel platens.
  • Continuous force measurement (accuracy ±1 %) and displacement measurement (accuracy ±5 % or ±0.1 mm, whichever is smaller).
  • Data recording system for force–displacement or stress–strain curves.
• Specimens:
  • Square or rectangular, minimum 100 mm × 100 mm.
  • Cut so base is normal to intended compression direction; do not layer specimens.
  • At least five specimens; use a new specimen for each test.
• Conditioning:
  • Standard laboratory atmosphere per ISO 554 (20 °C ±2 °C, 65 % ±5 % RH) unless demonstrated unnecessary.
  • Considered conditioned when successive weighings (≥2 h apart) change by ≤0.25 %.
• Test procedure:
  • Preload to (5 ±0.5) kPa, then compress at a constant displacement rate of 0.1 × initial thickness (di) per minute (±25 %).
  • Continue until collapse (maximum force) or until defined stress is reached (1 MPa).
• Calculations:
  • Short‑term compressive strength = maximum force / initial cross‑sectional area (expressed in kPa).
  • Compressive strain = 100 × displacement at maximum force / initial thickness.
  • If no failure before 1 MPa, report strain at 1 MPa.
• Reporting:
  • Include reference to ISO 25619-2, product ID, conditioning, specimen dimensions and number, all individual results and mean values, and any deviations/events.

Applications

• Routine quality control and batch verification of geosynthetic products (geotextiles, geospacers, cores).
• Comparative material characterization after exposure to stress, liquids or light.
• Laboratory testing to confirm short‑term compression performance and manufacturing consistency.

Who uses this standard

• Geosynthetic manufacturers and QC laboratories
• Independent testing laboratories and material engineers
• Product specifiers and procurement teams conducting acceptance testing

Related standards

• ISO 25619-1 (Compressive creep properties)
• ISO 7500-1 (Verification of uniaxial testing machines)
• ISO 554 (Standard atmospheres for testing)
• ISO 10318 (Geosynthetics - Terms and definitions)

Keywords: ISO 25619-2:2015, geosynthetics, short‑term compression behaviour, compressive strength, compression testing machine, stress–strain, quality control.