GCL systems.
Choose the construction and formulation.

LAMINATED RANGE

Four constructions. Granular or polymer modified.

Standard 37 and Standard 40 use a woven carrier of at least 100 g/m². Heavy Duty 37 and Heavy Duty 40 use a composite carrier of at least 300 g/m²: 100 woven plus 200 nonwoven. The cover nonwoven is at least 200 g/m². The 37 and 40 designations specify 3,700 and 4,000 g/m² minimum dry bentonite, excluding polymer.

U identifies sodium bentonite granules without polymer addition. P identifies polymer-modified sodium bentonite powder. Both formulations are available in each carrier, clay-loading and film combination. Formulation and source declarations identify the material supplied.

When to include polymer modification.

Unmodified bentonite is available for projects where typical low-salinity rainwater or compatible subgrade moisture hydrates the clay, subject to the project chemistry, confinement and hydraulic requirements. Consider polymer modification where higher resistance to drying and desiccation cracking is sought during extended exposure before covering, or where lime-affected water, highly saline water or certain leachates may hydrate the bentonite instead of typical rainwater. Select and verify the polymer formulation against the actual hydration liquid, pH, dissolved ions, confinement and exposure conditions. Polymer modification does not automatically qualify lime-treated fill or aggressive liquids. Cover promptly; permanent exposed service requires a separate design.

Technical data and test methods.

Six separate TDS cover the two bentonite formulations: four laminated sheets distinguish the 0.20 mm and 0.50 mm films, and two sheets cover the unlaminated range. Each compares Standard 37/40 and Heavy Duty 37/40. Values are specified minimum or maximum supply requirements, with nominal film thickness where applicable. Exact-grade manufacturer acceptance and traceable production verification are required before supply. Independent qualification of each selected construction remains pending.

All named grades specify tensile strength ≥10 kN/m in each direction under ASTM D6768 and internal GCL peel ≥360 N/m under ASTM D6496. For laminated grades, PE-to-cover peel is a separate ≥300 N/m requirement under an agreed procedure. These are acceptance requirements, not statistically established roll values.

Film, overlap and sealing options.

The PE film is specified by resin type and nominal thickness. The 0.50 mm option requires manufacturing qualification. Extrusion sealing also requires a qualified procedure for the actual film, filler and laminated assembly. Do not extrusion-seal HDL-GCL 020. Neither grade is wedge weldable.

Film remains bonded across each roll and loose at the designated longitudinal edges. Lift the loose film clear to form direct GCL-to-GCL contact, then return the PE above the joint. Measure both finished overlap widths without stretching the film. Use the project detail for end laps and field cuts; the longitudinal release zone is not an end-lap detail. Replace damaged laminated panels or use a Kontain-issued repair detail. Do not strip bonded film.

Bentonite swell requirements.

Unmodified U grades specify ≥24 mL/2 g in reagent water under ASTM D5890. Polymer P grades specify ≥28 mL/2 g in reagent water and ≥22 mL/2 g in the defined saline solution under a modified procedure. Saline values are not transferred to unmodified grades.

U grades: ASTM D5890 in reagent water, with a minimum 16 h hydration period after the final clay increment; extend and report readings as required by the method. P grades: D5890-based modified procedure, reporting at 16 h after the final increment in reagent water or 20,000 mg/L NaCl. Reagent water is distilled or deionised water meeting ASTM D1193. D5890-25 excludes polymer-containing clays, so P results are reported as modified tests. Supplier reference values for modified bentonite are ≥28 mL/2 g in tap water and ≥22 mL/2 g in unspecified 20,000 ppm salt water. The defined reagent-water, NaCl and 16 h conditions are acceptance requirements needing supplier confirmation. U-grade saline swell and saline conductivity are not declared.

Select the formulation for the actual subgrade, contact liquids, hydration sequence and confinement. Cover promptly to protect the liner through installation.

Bentonite quality requirements.

The range specifies sodium bentonite granules without polymer addition (U) or polymer-modified sodium bentonite powder (P). Powder grading applies to P grades only.

Verify formulation, source and lot traceability for the order. This commercial range does not establish compliance with a landfill specification. Assess the actual contact liquid, subgrade chemistry, confinement and lining design.

UNLAMINATED RANGE

Standard and Heavy Duty GCL without a laminate.

Choose Standard 37/40 with a woven carrier or Heavy Duty 37/40 with a composite carrier. Each is available with sodium bentonite granules without polymer addition (U) or polymer-modified sodium bentonite powder (P). The GCL codes identify the unlaminated grades; HDL-GCL codes identify laminated grades. Factory longitudinal overlaps are at least 300 mm; end joints and field cuts on a base require at least 600 mm with accessory bentonite treatment.

Soils, slopes and penetrations need a project detail.

Assess lime-treated soils, limestone, recycled concrete, saline pore water and process liquids before direct contact with bentonite. Polymer modification does not remove the need for compatibility testing.

Verify protection against the actual aggregate grading, angularity, load and placement method for the selected construction. Design slopes using hydrated internal and interface shear properties for the complete lining system. Keep plant off uncovered GCL and place compatible confinement promptly.

Supply format and project support.

Common rolls are 5 m × 30 m; dimensions and factory edge arrangements are agreed for each order. Confirm roll mass, core clear bore and lifting compatibility. The laminated range offers unmodified granules and polymer-modified powder. Unlaminated granular and powder options are selected by grade.

Send the liner section, slope geometry, soil grading and source, liquid chemistry, loading, penetrations and delivery location.