ISO Standards Relevant to Synthetic Geogrids
ISO 10319:2015 – Geosynthetics – Wide-width tensile test: This standard specifies the method for determining tensile strength and elongation of geogrids using a wide-width specimen (typically 200 mm) at a strain rate of 20% per minute and a test temperature of 20°C. It’s widely used for quality control and performance assessment.
ISO 9001:2015 – Quality management systems: Ensures consistent manufacturing quality, relevant for geogrid production.
ISO 10318-1:2015 – Geosynthetics – Terms and definitions: Provides standardized terminology for geogrid properties.
ISO 9863-1:2016 – Geosynthetics – Determination of thickness: Relevant for assessing geogrid rib or junction thickness.
Other standards (e.g., ASTM D6637, referenced in some sources) may complement ISO for specific tests like single or multi-rib tensile strength.
Comparative Study of Synthetic Geogrids by UTS
Below is a comparative table for synthetic geogrids with UTS ranging from 100 kN/m to 1200 kN/m. Since ISO does not provide specific product standards for each UTS level, I’ve synthesized typical properties based on industry data from sources like manufacturer specifications, BIS standards, and research papers. The table includes key parameters like material type, tensile strength at 2% and 5% strain, elongation at break, junction efficiency, and typical applications, which are critical for geogrid performance.
Notes on the Table
- Material: Most high-strength geogrids (≥100 kN/m) are made from high-tenacity polyester (PET) due to its low creep and high tensile strength. HDPE is common for lower UTS (e.g., 100 kN/m) in uniaxial or biaxial configurations.
- Tensile Strength at 2% and 5% Strain: These values are estimated based on typical ratios (20–30% of UTS at 2% strain, 40–60% at 5% strain) from industry data. Exact values depend on manufacturer specifications.
- Elongation at Break: PET geogrids typically have 10–13% elongation, while HDPE may be slightly higher (up to 15%).
- Junction Efficiency: Critical for load transfer in stabilization applications, typically 90–95% for high-quality geogrids.
- Applications: Higher UTS geogrids (e.g., 500–1200 kN/m) are used in extreme conditions like deep embankments or mega infrastructure projects.
- ISO 10319:2015: The primary standard for tensile testing, ensuring consistent measurement of UTS, strain, and elongation.
Additional Considerations
- Junction Efficiency vs. UTS: For stabilization (e.g., roads), junction efficiency and radial stiffness are more critical than UTS, as UTS alone doesn’t predict in-ground performance.
- Testing Conditions: ISO 10319 specifies a 200 mm wide specimen, 20% strain rate per minute, and 20°C temperature. Variations in temperature or strain rate can affect results.
- Durability: Standards like ISO 12956 (for UV resistance) or ISO 13438 (for chemical resistance) may be relevant for long-term performance.
- Limitations: UTS is less relevant for stabilization applications (e.g., roads) where confinement and interlock matter more. High UTS geogrids are better suited for reinforcement (e.g., retaining walls).
Geogrid Specifications
Explore the technical specifications of geogrid products, designed for various civil engineering applications.
| UTS (kN/m) | Material | Tensile Strength @ 2% Strain (kN/m) | Tensile Strength @ 5% Strain (kN/m) | Elongation at Break (%) | Junction Efficiency (%) | Polymer Type | Typical Applications | ISO Test Standard |
|---|---|---|---|---|---|---|---|---|
| 100 | PET/HDPE | 20–30 | 40–60 | 10–13 | 90–95 | Uniaxial/Biaxial | Retaining walls, road base | ISO 10319:2015 |
| 150 | PET | 30–45 | 60–90 | 10–12 | 90–95 | Uniaxial | Slopes, embankments | ISO 10319:2015 |
| 200 | PET | 40–60 | 80–120 | 10–12 | 90–95 | Uniaxial | Reinforced soil walls | ISO 10319:2015 |
| 250 | PET | 50–75 | 100–150 | 10–12 | 90–95 | Uniaxial | Heavy | ISO 10319:2015 |
| 300 | PET | 60–90 | 120–180 | 10–12 | 90–95 | Uniaxial | Landfill liners | ISO 10319:2015 |
| 350 | PET | 70–105 | 140–210 | 10–12 | 90–95 | Uniaxial | High | ISO 10319:2015 |
| 400 | PET | 80–120 | 160–240 | 10–12 | 90–95 | Uniaxial | Bridge abutments | ISO 10319:2015 |
| 500 | PET | 100–150 | 200–300 | 10–12 | 90–95 | Uniaxial | Heavy infrastructure | ISO 10319:2015 |
| 600 | PET | 120–180 | 240–360 | 10–12 | 90–95 | Uniaxial | Deep embankments | ISO 10319:2015 |
| 700 | PET | 140–210 | 280–420 | 10–12 | 90–95 | Uniaxial | Critical soil structures | ISO 10319:2015 |
| 800 | PET | 160–240 | 320–480 | 10–12 | 90–95 | Uniaxial | Extreme load applications | ISO 10319:2015 |
| 900 | PET | 180–270 | 360–540 | 10–12 | 90–95 | Uniaxial | Specialized projects | ISO 10319:2015 |
| 1000 | PET | 200–300 | 400–600 | 10–12 | 90–95 | Uniaxial | Mega infrastructure | ISO 10319:2015 |
| 1100 | PET | 220–330 | 440–660 | 10–12 | 90–95 | Uniaxial | Ultra | ISO 10319:2015 |
| 1200 | PET | 240–360 | 480–720 | 10–12 | 90–95 | Uniaxial | Extreme engineering | ISO 10319:2015 |