Overview
ISO 9863-1:2016 - "Geosynthetics - Determination of thickness at specified pressures - Part 1: Single layers" defines a standard laboratory method to measure the thickness of geosynthetic materials under specified pressures or point loads. The method produces identification data for product datasheets and can be used as an input to other test methods (for example hydraulic or compressive tests). It is applicable to all single-layer geosynthetics, including polymeric and bituminous barriers, geogrids, drainage geocomposites and other geosynthetic products.
Key Topics and Requirements
- Test principle: Measure thickness as the distance between a reference plate and a parallel presser-foot applying a defined pressure or point load; report mean thickness and coefficient of variation.
- Specified pressures/loads: Typical pressures are 2 kPa, 20 kPa and 200 kPa. For polymeric/bituminous barriers nominal thickness is defined at 20 ±0.2 kPa; textured barriers use a point load of 0.6 ±0.1 N.
- Presser-foot sizes and geometry: Defined sizes for different products:
- Polymeric/bituminous barriers: circular (10 ±0.05 mm) or square (≥100 × 100 mm)
- Other geosynthetics: presser-foot area ≈ 25 cm²
- Apparatus accuracy: Gauge resolution 0.01 mm; presser-foot must apply pressures within tight tolerances (±0.5%).
- Specimens and conditioning: Minimum 10 specimens per pressure; if new specimens are used for each pressure, at least 30 specimens are required. Condition specimens per ISO 554 (typically 24 h).
- Procedures A–D: Options include new specimen per pressure (A), incremental loading on same specimen (B), and special procedures for uniform (C) and non‑uniform (D) polymeric/bituminous barriers.
- Reporting: Must state procedure used, presser-foot size, conditioning atmosphere, number of specimens, mean nominal thickness (mm), coefficient of variation, and any deviations.
Applications
- Producing reliable nominal thickness values for product technical data sheets and quality control.
- Providing standardized input for related tests (e.g., hydraulic conductivity, compressive behaviour).
- Comparing products (geotextiles, geomembranes, geogrids) and verifying conformance to specifications.
- Useful in geotechnical engineering, landfill lining, drainage systems, road and rail reinforcement, and environmental containment design.
Who uses it:
- Manufacturers and R&D laboratories for product characterization
- Testing laboratories and quality assurance teams
- Specifiers, design engineers and contractors when selecting geosynthetics for projects
Related Standards
- ISO 554 - Standard atmospheres for conditioning/testing
- EN ISO 9862 - Sampling and preparation of test specimens for geosynthetics
- EN ISO 25619-1 - Determination of compressive behaviour (relevant for drainage geocomposites)
Keywords: ISO 9863-1, geosynthetics, thickness determination, nominal thickness, presser-foot, test method, specimen conditioning, technical data sheet.
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