About Geosynthetic Clay Liners (GCL) Guide

What is a Geosynthetic Clay Liner (GCL)?

Geosynthetic Clay Liners (GCLs) are engineered materials designed primarily for lining applications to prevent water seepage and soil erosion. Comprising bentonite clay sandwiched between layers of geotextiles, GCLs swell upon hydration, forming a natural impermeable barrier.

Types of GCL

GCLs vary based on their bentonite composition, structure, and the presence of liners:

• Standard GCL: Bentonite clay encapsulated between woven (carrier) and nonwoven geotextile layers.

• GCL with HDPE Liner: Provides enhanced waterproofing and anti-seepage performance.

• Reinforced GCL: Enhanced stability using reinforced nonwoven geotextile layers (RNP, RNP2).

Powdered vs Granular Bentonite

• Powdered Bentonite: Best for smooth and uniform hydration; effective in salt-resistant polymer-modified applications. Preferred for landfill containment and when barrier protection is a priority.

• Granular Bentonite: Offers robust general performance and is easier to handle, making it more popular and widely applicable.

Typical Roll Widths

GCL is commonly available in roll widths of:

• 2.5m (recommended for farming applications)

• 5m (standard industrial and larger project sizes)

Roll lengths typically range from 30m to 40m. Rolls with lengths greater than 30m usually require a steel core for stability.

Applications for GCL with Liner

GCL integrated with an HDPE liner (0.2mm to 1.0mm thickness) is ideal for projects requiring high levels of waterproofing and seepage prevention, such as landfill coverage, wastewater retention ponds, and areas with sensitive environmental conditions.

Slope Angle Considerations

• Maximum Effective Slope: Typically up to 2:1, but commonly applied at 3:1 or 4:1.

• Vertical applications are feasible when secured with shotcrete.

• Covering with 30cm of soil is generally recommended; steep slopes may require additional considerations.

Key Characteristics to Consider

• Bentonite Density: The most influential factor determining the liner's performance. InfraClay3700G, containing 3700gsm granular bentonite, is the most widely applicable option.

• Substrate Condition:

  • Average soil: InfraClay3600G suffices.

  • Rocky or gravelly soil: Opt for InfraClay4000G or higher for enhanced protection.

• Edge Treatment: All rolls have 300mm bentonite-impregnated edges for optimal overlap sealing.

Size and Packaging

• Standard rolls are typically measure 35m long and 5m wider, custom sizes are also available.

• Handling requires forklift assistance due to weight.

• Specialised forklift arms are recommended for unloading from containers

Ordering and Quotation Process

1. Obtain site photos for preliminary assessment.

2. Forward site details to to us for recommendations.

3. Larger projects (over 2250sqm) benefit from full-container orders for cost-effective logistics.

Special Considerations

Roll Core Material

• PVC core: Suitable for standard rolls (5m x 30m).

• Steel core: Required for rolls exceeding 30m length (adds cost).

Installation for Farming Applications

• For deployment usage of spreader bars are recommended

• View a straightforward farm dam installation example here.

Applications

• Erosion control

• Wastewater retention

• Landfill liners and coverage

• Soil separation

Product Coding System

Our naming clearly indicates the bentonite content, crucial for performance:

InfraClay[Bentonite_gsm][G/P][S]-[liner_thickness][HL]-[roll_width][W]-[core_material][C]

• G/P: Granules (G) or Powder (P)

• S: Salt-resistant variant

• HL: HDPE Liner with specified thickness (0.2mm, 0.5mm, 1.0mm)

• Core Materials: STEEL, PVC, HDPE, CARD

Examples:

• InfraClay3700G: 3700gsm granular bentonite

• InfraClay3700G-02HL: 3700gsm granular bentonite + 0.2mm HDPE liner

• InfraClay3700G-5W-STEELC: 5m wide roll, steel core

InfraClay3700G is the recommended general-purpose GCL.

For specific guidance, detailed project assessments, or further technical support, please reach out to our team.