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Geosynthetic Clay Liners (GCL)

Geosynthetic clay liners (GCL) is used across a range of civil engineering and building applications. It contains the clay mineral sodium bentonite - a natural sealant that swells on contact with water - and is sandwiched between two layers of geotextiles, a woven and a nonwoven, that are mechanically needle-punched together to provide shear strength.

Our top-performing, self-sealing and self-healing clay liners, comply with the latest industry codes of practice. The perfect solution for where containment is required to act as a hydraulic barrier to leachate from landfill sites or as a SUDs pond liner.

Geosynthetic clay liner

GCL 4500 is a woven fabric-like material, primarily used as a fluid barrier for use in the construction of liquid waste disposal sites. The granular bentonite clay is sandwiched between a woven and nonwoven geotextile, resulting in a very strong robust product.


  • Solid waste and hazardous waste landfill areas
  • Ponds and pools
  • Dams
  • Irrigation channels and water transfer lines
  • Landslide repairs and similar ground reinforcement applications
  • Base insulations in flood controls

Functions of geosynthetic clay liners


Collects and transports fluids within its thickness

Erosion control

Prevents wind or water surface erosion


Stress reduction layer to prevent or reduce damage


Resists stresses or reduces deformations

GCL 4500 Specification

Properties of Geotextile

Test method Values Unit
Cover layer EN ISO9864 (EN965) 200 g/m2
Carrier layer EN ISO9864 (EN965) 100 g/m2

Properties of Bentonite

Test method Values Unit
Montmorillonite content CUR 33 ≥ 75 %
Swell index ASTM D 5890 ≥ 24 ml/2g
Mass per unit area (1) EN 14196 4500 g/m2

Geosynthetic Clay Liner Specification

Test Method Values Unit Tolerance
Mass per unit area (1) EN 14196 4800 g/m2 ±10%
Thickness EN ISO9863-1/9863-2 6.8 mm ±1mm
Tensile strength MD EN ISO 10319 ≥ 10.4 kN/m -1kN/m
Tensile strength CMD EN ISO 10319 ≥ 8.5 kN/m -0.8kN/m
CBR Puncture strength EN ISO12236 ≥ 1800 N -200N
Index flux ASTM D 5887 / DIN18130 ≤ 5.0 x 10-9 m3/m2/s  
Permeability /K - value ASTM D 5887 ≤ 5.0 x 10-11 m/s  
Peel strength (2) ASTM D6496 ≥ 60 N/10cm -6N/10cm
Roll sizes (min)   5.1 x 4.0 m ±1%
Quantity   204 m2  

(1) At 12% moisture content
(2) Max peak