ISO 10321:2008

Overview - ISO 10321:2008 (Geosynthetics tensile test for joints/seams)

ISO 10321:2008 specifies an index tensile test method for determining the tensile properties of joints and seams in geosynthetics using a wide‑width strip specimen. The method quantifies the maximum tensile strength of a seam or joint (expressed in kN/m) and allows calculation of joint/seam efficiency relative to the unseamed material. The procedure applies to most geosynthetics (including geogrids with modified specimen dimensions) but is not applicable to polymeric or bituminous geosynthetic barriers. Procedures are given for both conditioned (standard atmosphere) and wet specimens.

Key topics and technical requirements

• Specimen geometry and preparation
  • Standard specimen width: 200 mm, with the seam/joint centered and 25 mm extensions each side for stability.
  • Initial jaw separation: 100 mm + joint/seam width (±3 mm).
  • Minimum of five specimens per condition; five additional if wet testing is required.
  • Special instructions for woven/nonwoven geotextiles, geogrids and knitted products (thermal cutting permitted with care).
• Test apparatus and settings
  • Constant rate of extension tensile testing machine compliant with ISO 7500‑1 (Class 2 or better).
  • Jaws wide enough to grip entire specimen (≥200 mm face) - wedge, compressive block or capstan examples provided to limit slippage.
  • Strain rate: set cross‑head speed to induce (20 ± 5) %/min strain between jaws.
• Conditioning and wet testing
  • Standard atmosphere per ISO 554: 20 °C ± 2 °C, 65 % RH ± 5 % RH.
  • Wet specimens: immersion in water at 20 °C ± 2 °C for at least 24 h; up to 0.05 % non‑ionic wetting agent permitted.
• Results and calculations
  • Joint/seam strength T (kN/m) = Fmax × c (c depends on specimen width or number of tensile elements).
  • Joint/seam efficiency (%) = 100 × (Tjoint / Tunjointed) - Tunjointed determined by ISO 10319.
• Quality and discard criteria
  • Rules for discarding outliers (e.g., premature failures due to preparation, jaw slippage) and required reporting of failure modes.

Applications

• Routine quality control and batch testing of seamed geosynthetic products.
• Product development and comparative testing of seam/joint methods (stitching, welding, seaming).
• Providing design input for engineers seeking quantified seam/joint strength and efficiency for use in specifications and procurement.

Who uses this standard

• Geosynthetic manufacturers and fabricators
• Independent testing laboratories and QA/QC teams
• Civil and geotechnical engineers specifying geosynthetic seams
• R&D teams validating jointing methods and materials

Related standards

• ISO 10319 - Wide‑width tensile test (unseamed material)
• ISO 10318 - Geosynthetics terms and definitions
• ISO 9862 - Sampling and specimen preparation
• ISO 554, ISO 7500‑1, ISO 3696

Keywords: ISO 10321:2008, geosynthetics tensile test, seam strength, joint efficiency, wide‑width strip method, geotextiles, geogrids, tensile testing.