Bentofix® geosynthetic clay liner for sealing | Naue

Bentofix® geosynthetic clay liner for sealing | Naue | Naue

Application areas

Landfill base and cap lining: geosynthetic clay liner for waste containment
Typical applications:
Landfill base liners in single and composite lining systems
Landfill capping and final closure systems
Leachate containment beneath engineered fill
Gas and vapour seals in landfill covers (Bentofix^® X variants)
Bentofix^® is the specified geosynthetic clay liner for landfill base and capping applications where leachate containment and gas control are required. The Thermal Lock shear strength enables steep slope liner installations in lined waste cells. Bentofix^® BFG 5000 all-direction self-sealing overlaps reduce seaming risk in complex geometries. NSP 4900 holds LAGA approval for landfill capping class I and II. CE marking per EN 13491 confirms declared hydraulic performance.
Advantages in landfill applications:
10 mm GCL preserves maximum landfill airspace vs 400 mm CCL
Self-healing tolerates differential settlement under fill loads
BFG 5000: all-direction self-sealing overlaps for lining complex geometries
Bentofix^® X2/X5F: gas and ion exchange protection for aggressive leachate environments
NSP 4900: LAGA approval for landfill capping class I and class II (Germany)
To the application:
Landfill engineering
GCL groundwater protection: Bentofix^® for roads, railways and retention basins
Typical applications:
Environmental protection liners under roads (RiStWag)
Protection under motorways, railways and airports (M TS E)
Retention basins and stormwater attenuation ponds
Secondary containment for fuel and chemical storage facilities
Bentofix^® geosynthetic clay liner is the engineered barrier for groundwater protection in infrastructure applications. The NSP 5400 DB holds HPQ designation under DBS 918 039 for Deutsche Bahn railway earthworks (Application 3.11, TM 4-2015-10838 I.NPF 2 of 10.11.2015). Self-healing is critical for infrastructure projects with post-construction settlement risk. WHG-compliant systems meet German water law requirements for roads and motorways.
Advantages in groundwater protection:
NSP 5400 DB: only GCL with HPQ designation for DB Application 3.11
WHG-compliant: meets RiStWag and M TS E requirements for German roads
10 mm profile reduces pavement reconstruction depth
5.0 m wide rolls cover large infrastructure areas with minimal seaming
To the application:
Further use cases
- Water containment and hydraulic engineering
  Reservoir and pond liners
  Dams and canals
  Flood protection embankments
  Aquaculture ponds
- Mining and tailings
  Tailings storage facility base and side slope liners
  Heap leach pad liners
  Mine water evaporation ponds
  Mine closure
- Tunnel and structural waterproofing

Technical properties

Property	Unit	BFG 5000	NSP 4000	NSP 4900
Cover layer
Geotextile type	—	Needle-punched nonwoven PP	Needle-punched nonwoven PP	Needle-punched nonwoven PP
Mass per unit area	g/m²	300	220	≥ 200
Bentonite filling of cover NW	g/m²	800 (entire surface)	800 (50 cm at each length edge)	800 (50 cm at each length edge)
Bentonite layer
Bentonite type	—	Sodium bentonite powder	Sodium bentonite powder	Sodium bentonite powder
Property	Unit	BFG 5000	NSP 4000	NSP 4900
Bentonite grain size	mm	≤ 0.2	≤ 0.2	≤ 0.2
Mass per unit area (at ≤ 15 % moisture content)	g/m²	5,000 (incl. cover NW filling)	3,670	4,670
Swell index	ml/2 g	≥ 24	≥ 24	≥ 24
Fluid loss	ml/2 g	≤ 18	≤ 18	≤ 18
Moisture content	%	10	10	≤ 15
Carrier layer
Property	Unit	BFG 5000	NSP 4000	NSP 4900
Geotextile type	—	Slit-film woven PP	Slit-film woven PP	Slit-film woven PP
Mass per unit area	g/m²	200	110	≥ 100
Geosynthetic clay liner
Mass per unit area (at ≤ 15 % moisture content)	g/m²	5,500	4,000	5,000
Thickness, dry	mm	7.0	6.0	6.0
Tensile strength, max., MD	kN/m	20	13.0	13.0
Property	Unit	BFG 5000	NSP 4000	NSP 4900
Tensile strength, max., CMD	kN/m	11	13.0	13.0
Elongation at maximum tensile force, MD	%	8	10	10
Elongation at maximum tensile force, CMD	%	4	6	6
Peel strength, maximum peak value	N/10 cm	≥ 60	≥ 60	≥ 60
Peel strength, average value	N/m	≥ 360	≥ 360	≥ 360
Internal shear strength (24 h hydration, 20 kPa)	kPa	≥ 35	≥ 35	≥ 35
Property	Unit	BFG 5000	NSP 4000	NSP 4900
Static puncture test (CBR)	N	2,500	2,200	2,200
Permeability k₁₀	m/s	1.0 · 10⁻¹¹	1.2 · 10⁻¹¹	1.2 · 10⁻¹¹
Permittivity ψ₁₀	1/s	1.5 · 10⁻⁹	2.5 · 10⁻⁹	1.7 · 10⁻⁹
Index flux q₁₀	(m³/m²)/s	2.2 · 10⁻⁹	3.5 · 10⁻⁹	2.6 · 10⁻⁹
Overlaps, quality assurance and delivery form
Overlapping areas, self-sealing	—	Longitudinal and transverse	Longitudinal	Longitudinal
Property	Unit	BFG 5000	NSP 4000	NSP 4900
Needle detector tested	—	Yes	Yes	Yes
Fibre bond thermally treated on carrier side	—	Yes	Yes	Yes
Roll width	m	5.0	5.0	5.0
Roll length	m	40	50	50
CO₂-eq, cradle to grave (A1–C4)	kg CO₂-eq/m²	6.43	6.43	6.43

Split-view illustration of a roadside stormwater retention basin comparing a compacted clay liner with a Bentofix® geosynthetic clay liner. The left side shows a multi-layer compacted clay barrier, while the right side shows a thin Bentofix® liner beneath the cover soil. Both basins have the same water level, illustrating the reduced liner thickness of the geosynthetic solution. — Comparison of a conventional compacted clay liner on the left and a Bentofix^® geosynthetic clay liner on the right in a roadside stormwater retention basin. The illustration highlights the significantly reduced barrier thickness of the geosynthetic solution while maintaining the same storage volume.

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Typical applications:

Landfill base liners in single and composite lining systems
Landfill capping and final closure systems
Leachate containment beneath engineered fill
Gas and vapour seals in landfill covers (Bentofix^® X variants)

Bentofix^® is the specified geosynthetic clay liner for landfill base and capping applications where leachate containment and gas control are required. The Thermal Lock shear strength enables steep slope liner installations in lined waste cells. Bentofix^® BFG 5000 all-direction self-sealing overlaps reduce seaming risk in complex geometries. NSP 4900 holds LAGA approval for landfill capping class I and II. CE marking per EN 13491 confirms declared hydraulic performance.

Advantages in landfill applications:

10 mm GCL preserves maximum landfill airspace vs 400 mm CCL
Self-healing tolerates differential settlement under fill loads
BFG 5000: all-direction self-sealing overlaps for lining complex geometries
Bentofix^® X2/X5F: gas and ion exchange protection for aggressive leachate environments
NSP 4900: LAGA approval for landfill capping class I and class II (Germany)

Photo showing the installation/laying of Bentofix® geosynthetic clay liner at a landfill construction site.

To the application:

Landfill engineering

Typical applications:

Environmental protection liners under roads (RiStWag)
Protection under motorways, railways and airports (M TS E)
Retention basins and stormwater attenuation ponds
Secondary containment for fuel and chemical storage facilities

Bentofix^® geosynthetic clay liner is the engineered barrier for groundwater protection in infrastructure applications. The NSP 5400 DB holds HPQ designation under DBS 918 039 for Deutsche Bahn railway earthworks (Application 3.11, TM 4-2015-10838 I.NPF 2 of 10.11.2015). Self-healing is critical for infrastructure projects with post-construction settlement risk. WHG-compliant systems meet German water law requirements for roads and motorways.

Advantages in groundwater protection:

NSP 5400 DB: only GCL with HPQ designation for DB Application 3.11
WHG-compliant: meets RiStWag and M TS E requirements for German roads
10 mm profile reduces pavement reconstruction depth
5.0 m wide rolls cover large infrastructure areas with minimal seaming

To the application:

Groundwater protection

Water containment and hydraulic engineering
- Reservoir and pond liners
- Dams and canals
- Flood protection embankments
- Aquaculture ponds
Mining and tailings
- Tailings storage facility base and side slope liners
- Heap leach pad liners
- Mine water evaporation ponds
- Mine closure
Tunnel and structural waterproofing
- Cut-and-cover tunnel waterproofing
- Below-grade structures
- Underground car parks
- Railway tunnel lining
Environmental and ecological restoration
- Flood protection embankments
- Historic moat rehabilitation
- Ecological restoration
- Ornamental ponds

Bentofix^® is a geosynthetic clay liner (GCL) for waterproofing and containment. It consists of sodium bentonite powder needle-punched between two PP geotextile layers. It is used in landfill base and cap lining, groundwater protection, reservoirs, mining and tunnel waterproofing.

Bentofix^® BFG 5000 pricing depends on project size, grade specification and quantity. Contact Naue for a project-specific quotation. Bentofix^® GCLs replace 400 mm compacted clay liners: the material cost difference is typically offset by reduced excavation and installation costs.

Bentofix^® is a geosynthetic clay liner: it uses swelling sodium bentonite as the hydraulic barrier. A geomembrane (such as Carbofol^® HDPE) uses a polymer film. GCLs self-heal after minor damage. In composite systems, both are combined: GCL below the geomembrane for double-barrier protection.

Use Bentofix^® X variants when enhanced chemical resistance, gas barrier, root penetration resistance or desiccation resistance is required. X2 has a smooth PE coating (200 g/m²); X5F has a structured PE coating (500 g/m², 0.4 mm nod height) for steep slopes (interface friction ≥ 9 kPa at 20 kPa, ASTM D6243). BFG 5000 is the standard grade for landfill and groundwater protection without aggressive chemical exposure.

Thermal Lock needle-punching anchors over 2,000,000 fibres/m² uniformly through the bentonite and bonds them thermally to the carrier geotextile. This provides directionally independent shear strength, enabling installation on slopes of 2.5:1 or steeper, where standard GCLs fail under shear loading.

Bentofix^® has a published EPD: 6.81 kg CO₂-eq/m². A compacted clay liner requires borrow pit operations, heavy plant compaction and long-distance haulage: the carbon cost is project-dependent and typically higher.

Bentofix^® holds CE marking (EN 13491), ISO 9001, BBA-HAPAS cert. no. 05/4256 (BFG 5000 and X2 BFG 5300), LAGA approval (NSP 4900, landfill capping class I and II), IVG certificates (NSP 4000, NSP 4900, BFG 5000), BAW test reports (BFG 5000) and WHG compliance for German water law. NSP 5400 DB holds DBS 918 039 HPQ for Deutsche Bahn railway earthworks.

Yes, EPD reference is available upon request. The EPD supports BREEAM, LEED and DGNB certification. Total CO₂-eq: 6.81 kg CO₂-eq/m² (A1 to C4 system boundary).

Bentofix^® BFG 5000 achieves 2,500 N static puncture resistance (EN ISO 12236). X5F BFG 5300 achieves 3,300 N. The cover nonwoven protects the bentonite core during handling. 5.0 m wide rolls with a 30 cm colour-coded overlap guide simplify installation. All grades are continuously needle-detector tested during manufacture.

Standard NSP and BFG grades: 5.0 m wide x 50 m long (250 m² per roll). Bentofix^® X2 and X5F BFG 5300: 4.85 m wide x 40 m long (194 m² per roll). All grades have a 30 cm colour-coded overlap guide.

Bentofix^® is designed and tested to EN 13491 (CE marking), EN ISO 10319 (tensile strength), EN ISO 12236 (static puncture), EN 16416 / ASTM D5887 (hydraulic conductivity), ASTM D5890 (swell index) and ASTM D6496 (peel strength). NSP 5400 DB additionally meets DBS 918 039 for Deutsche Bahn applications.

Yes. Naue provides project-specific grade selection, system design and installation guidance. This includes leachate chemistry assessment, slope stability analysis and interface friction testing data for slope liner design. Contact Naue via the project request form.

Yes. The Thermal Lock process enables Bentofix^® to be installed on slopes of 2.5:1 or steeper. The directionally independent shear strength prevents bentonite migration under gravity loading. For X variants, the textured PE coating (X5F: ≥ 9 kPa at 20 kPa; X10F: ≥ 15 kPa at 20 kPa, ASTM D6243) provides additional interface friction on slopes.

Bentofix^® X variants (X2, X5F, X10F) are specified for chemically aggressive environments. The PE extrusion coating protects the sodium bentonite against ion exchange in leachate with high ionic strength. NSP 4900 holds LAGA approval for landfill capping class I and II. For standard landfill leachate, NSP or BFG grades are typically specified.

Bentofix® Geosynthetic clay liner

Bentofix® geosynthetic clay liner functions:

Barrier

Separation

Bentofix® advantages: why engineers specify this geosynthetic clay liner

Self-sealing and self-healing

Only 10 mm installed thickness

Thermal Lock: uniform shear strength

Globally certified

Quick and cost-effective installation

Application areas

Landfill base and cap lining: geosynthetic clay liner for waste containment

GCL groundwater protection: Bentofix® for roads, railways and retention basins

Further use cases

Technical properties

Certificates

CE marking (EN 13491)

BBA-HAPAS certificate no. 05/4256

LAGA approval (NSP 4900)

WHG-compliant

DBS 918 039 HPQ (Deutsche Bahn)

ASTM standards

Naue Portal: your all-in-one free geotechnical software solution for planning and cost estimation

Bentofix® geosynthetic clay liner projects: case studies

Geogrid-powered stability for Thurrock energy

Levee reinforcement in Beesel, The Netherlands

Artificial pond at Xiamen University, Sepang

Expanding Szeged regional landfill with an integrated geosynthetic sealing system

Frequently asked questions

Related Naue geosynthetic barrier products

Bentofix® + X

Bentofix® Green

Bentofix® X

Carbofol®

Carbofol® +

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Landfill base and cap lining: geosynthetic clay liner for waste containment

GCL groundwater protection: Bentofix® for roads, railways and retention basins

Further use cases

Bentofix® geosynthetic clay liner vs compacted clay liner

Bentofix® specifications

Environmental Product Declaration - EPD

Geomembranes brochures

Naue publications

Solutions brochures

What is Bentofix® and what is it used for?

What does Bentofix® BFG 5000 cost?

What is the difference between Bentofix® and a geomembrane?

When should I use Bentofix® X2 or X5F instead of BFG 5000?

Why does Thermal Lock shear strength matter more than tensile strength alone?

How much CO₂ does Bentofix® produce compared to a compacted clay liner?

What certifications does Bentofix® hold?

Is there an Environmental Product Declaration for Bentofix®?

How robust is Bentofix® during installation?

What roll sizes does Bentofix® come in?

Which standards is Bentofix® designed to?

Does Naue offer planning support for Bentofix®?

Can Bentofix® be used on steep slopes?

Is Bentofix® suitable for chemically aggressive environments?

Bentofix^® Geosynthetic clay liner

Bentofix^® geosynthetic clay liner functions:

Bentofix^® advantages: why engineers specify this geosynthetic clay liner

GCL groundwater protection: Bentofix^® for roads, railways and retention basins

Bentofix^® geosynthetic clay liner projects: case studies

Bentofix^® + X

Bentofix^® Green

Bentofix^® X

Carbofol^®

Carbofol^® +

Bentofix^® geosynthetic clay liner vs compacted clay liner