AP

PL

IC

AT

IO

N

Bentofix®APPLIED KNOWLEDGE IQ

The Inventor of Needle-punched Geosynthetic

Clay Liners. Outstanding Quality and Longest Experience.

Bentofix® - The Original!

Bentofix® IQ addresses four subjects key to understanding geosynthetic clay liners (GCLs): Technics,

Quality, Application and Ecology. It describes the intelligence and importance of this product type,

which was invented by NAUE in 1987, and highlights the intelligent use of needle-punched GCLs in

sealing applications. Today, the Bentofix® IQ approach is guided by the classical elements of water,

fire, earth and air as critical issues such as proper GCL production, design, application and installa-

tion. Bentofix® IQ encourages GCL users to utilize these classical elements to understand those four

key GCL subjects: Technics (water), Application (earth), Quality (fire) and Ecology (air).

Bentofix® geosynthetic clay liners(GCLs) are produced in varioustypes, which is especially impor-tant in hydraulic engineering ap-plications. This allows Bentofix® to be installed in dry or wet con-ditions, and even underwater.With durable, robust geotextileouter layers and a uniform, high-swelling core of sodium ben-tonite, Bentofix® GCLs provide anideal barrier for hydraulic instal-lations. They prevent both waterloss and water incursion, makingthem outstanding containmentand protection solutions forcanals, dykes, dam liners, floodembankments, water reservoirsand other situations requiringstrong performance against hy-draulic heads.

Canals:The sealing of canals has becomemuch more important. Water lossdue to seepage limits agriculturalproductivity. Erosion threatens thesafety of shipping and recreationalcanals. Bentofix® GCLrolls are moreeconomical to install and more stable against internal erosion than

conventional compacted clay. Ingeneral, the hydraulic head concernwith a GCL-lined canal is lesser, be-cause of a dependable, steady head.Also, desiccation or freeze/thawconcerns can be alleviated by theconstant hydration of the GCL seal-ing system. Ensuring the true per-formance of the GCL, then, dependsupon strong bentonite encapsula-tion. This protects the core fromwave action. The uniform needle-punching of more than two millionfibres per sqm in Bentofix® preventslateral bentonite movement. Withproper GCL selection and construc-tion design, bentonite piping con-cerns are eliminated. A special ver-sion of Bentofix® (BZ13-B) enablesunderwater installation - somethingother liners are not capable of.

Dams:Like canals, dams (e.g. in waterreservoirs) generally require designswith permanent hydraulic heads.Bentofix® GCLs have been utilizedin a number of dam installations,such as for inland shipping routeswith an elevation higher than the natural groundwater. These in-

stallations must be guarded againstseepage loss. Bentofix® GCLs areperfectly suited for this. Dam slopestypically are steep and internalshear strength and interface fric-tion angles are often of concern.Scrim-reinforced Bentofix® GCLswith nonwoven geotextiles on bothsides typically allow steeper designsthan similar materials with wovencomponents. The nonwoven elementincreases interface friction angles.For underwater installations Bento-fix® BZ13-B allows installation evenunder faster currents. It features anintegral sand ballast layer that is

encapsulated by a nonwoven geo-textile. Once installed, Bentofix®BZ13-B stays put and withstandsthe placement of heavy armor rock. Levees and coastal dykes:Levees and dykes present interest-ing challenges. Levees must with-stand temporary loads. Coastaldykes are subjected to waves and

potential overtopping. Both scenar-ios impact flood defenses. Bentofix®GCLs provide the essential seal toprotect against erosion and failure-inducing seepage. An approx. 10 mm-thick layer of hydrated Bentofix® outperforms a 60 cm-thick com-pacted clay liner on cost and long-term performance. When installed onthe upstream surface, high-swellingpowdered sodium bentonite offers anexcellent low permeability seal. Slopeangles of 2.5:1 (H:V) or greater arepossible with Bentofix® GCLs due tothe needle-punched surface structureof the cover and carrier nonwovens,

as well as the large internal and ex-ternal shear strength. The more ro-bust Bentofix® BFG 5000 features acover nonwoven geotextile that hasbeen uniformly impregnated with asecond layer of sodium bentonitepowder, which can help an installa-tion proceed more efficiently versusinstallations where the overlaps mustbe sealed with additional bentonite.

Testing confirms:Independent testing of in-serviceBentofix® GCLs by the German Fed-eral Waterways Engineering and Re-search Institute (BAW) has con-firmed their durability and perfor-mance. Even after years of service,Bentofix® continues to meet strin-gent material specifications andperformance criteria. Outstandinghistorical performance in flood defenses is even helping to writenew levee construction codes.

Bentofix® IQHydraulic Applications

»Water runs down the hill, not through Bentofix®«

Fig. 1Permeability ofBentofix® GCLs in dependence

of water head andconfining stress.

The IQ of Technics: Excellent hydraulic barrier, high shear performance, robust components, durable geosynthetics

NAUE’s 1987 invention of the needle-punched method of manu-facturing geosynthetic clay liners(GCLs) changed the field. The ad-vance enabled not only the rapid,safe production of GCLs but the efficient shipping of GCLs in rolls.These moves lowered cost whilemaintaining the high level of prod-uct quality, thus expanding theavailable applications for GCLs.Also, the previously low friction co-efficient of the bentonite used inGCL cores ceased to be of concern.The needle-punching of a nonwo-ven geotextile outer layer trans-ferred the shear stress from the clayto the highly engineered geotextileto which the sodium bentonite was

bonded. Bolstered by this techno-logy, Bentofix® geosynthetic clayliners (GCLs) established themselvesquickly in landfill applications. Capping systems: The most common use for Bento-fix® GCLs in landfill construction isfor the creation of long-term cap-ping systems. Whether it is a mu-nicipal solid waste facility, a con-struction and demolition cell, orsomething more industrial (such asa fly ash landfill), an impermeablecover barrier is essential for suc-cessful closure, landfill stability,and potential site reuse. The ex-ceptional swelling properties ofsodium bentonite and the needle-punched nonwoven geotextilestrength of Bentofix® provide out-standing containment and durabi-

lity. Rainwater incursion is pre-vented and the GCL panels possessenough flexibility to adjust to dif-

ferential settlement without losingtheir uniform thickness and per-formance quality. In addition totheir stronger performance versustraditional compacted clay-onlysystems, Bentofix® provides eco-nomical and environmental bene-fits that traditional mineral seals cannot. The thinner profile ofBentofix® means that waste in-stallations have greater volume. In waste management, air spaceequals profitability. But GCL rollsare also more economical from ashipping and installation stand-point. Fewer deliveries and fasterinstallation reduce cost. And sig-nificantly fewer truckloads of GCLrolls are needed to cap a landfill,whereas compacted clay requiresmany truckloads. The use of Bento-

fix®, then, reduces transportationpollution and minimizes the miningclay from elsewhere. Combined withother geosynthetics (e.g. NAUE Secudrain® drainage composites) aBentofix® capping system managesleachate strongly, keeps out rain-water, and enables other beneficialclosure activities, such as methaneharvesting below the cap and vegetation establishment above.

Base sealing:Waste management professionalsmust comply with some of thestrictest environmental regulations.These codes call for strong sealingsystems beneath landfills to protectgroundwater during active landfilloperations and long-after final clo-sure. Bentofix® GCLs have played animportant role in these critical basesealing systems, most often in com-posite liner systems such as withCarbofol® HDPE geomembranes forprimary barriers and geocompositesfor leachate and gas management.Sodium bentonite-based Bentofix®GCLs provide essential security in

base sealing systems. In the eventof a breach in the primary barrier,Bentofix® provides the same im-permeable, self-sealing protectionit does for landfill cover systems,hydraulic barriers, and other instal-lations where soil and groundwatermust be protected.

Slopes:One of the biggest challenges toany waste cell’s containment sys-tem is the integrity of the sealedslopes. This applies to both coversystems and primary base liners.The weight of waste and soil cov-erage can be tremendous. Butgeosynthetic clay liners performjust as well on slopes in sealingsystems as they do on flat portionsof the installation, such as in composite base lining systems beneath the landfill. The strengthof Bentofix® GCLs along landfill capand bottom liner slopes is the result of the needle-punched non-woven outer layer, which providesthe necessary internal reinforcementto manage shear stress benefit.

»The feather in your (landfill) cap«

Bentofix® IQLandfill Applications

Fig. 2Effect of per-meability oncepermeated with leachate.

The IQ of Quality: High-swelling bentonite, quality-controlled components, superior manufacturing method, years of research experience

Roads and railways commonlyuse geosynthetic technologiesfor applications such as sub-grade reinforcement, separationof fines, drainage and erosioncontrol. But Bentofix® geosyn-thetic clay liners are alsoutilised in infrastructure. Con-tainment, in fact, is a growingneed for environmental protec-tion in transportation applica-tions.

Roads:Stormwater retention ponds collect rainwater runoff. Withits easy-to-delivery, easy-to-install rolls, Bentofix® providesthe essential seal for runoffponds so that the underlying

soils are not overtaxed. Sensi-tive locations, such as roadsbuilt adjacent to wetlands, in-creasingly call for protectionlike this, especially to preventthe seepage of automotive-related liquid contaminantsinto the soil. Also, Bentofix®

can provide a base liner be-neath roads and slopes for exceptional environmental protection. In applicationswhere friction angle is a con-cern, e.g. on steep slopesBentofix® GCLs with nonwovengeotextiles on both side arethe solution. They increase the interface friction angle,which enables secure slope installations; and their ro-bustness provides exceptionaldurability. Freeze/thaw ef-fects and dry/wet cycles aregenerally not a concern inthese applications, so long as a standard cover material thickness (e.g., greater than800 mm) is used.

Railways:As in road design, environmen-tal protection is of growing im-portance in rail applications to prevent contaminated liq-uids from migrating into soils,threatening wells, impairingwater catchment zones, etc.

The high-swelling sodium ben-tonite in Bentofix® provides an effective, long-term barrieragainst unwanted seepage, including for track drainage systems and protection of ad-jacent land. Bentofix® GCLs

are uniformly needle-punchedthrough all three layers (outergeotextile layers and interme-diate bentonite core). This nee-dle-punching creates a uniformencapsulation of the sodiumbentonite by over 2 million

fibres per square metre whichalso withstands dynamic forcesduring the service life.

Noise Barriers:The installation of noise barri-ers along roads and railwayscan help gain project approval

by providing both a safety andstress-relieving barrier betweenresidents and important tran-sit corridors. But barriers aremore complicated than manyrealize. They often must usesteep slopes, because the space

in which they are constructed is limited. (Most of the space is reserved for roads or rails.)Drainage and erosion concernsmust also be addressed so thatthe barrier does not negativelyimpact the road or railway. Andif local soils cannot be used,the cost of the barrier will morethan likely be too high for approval. Geosynthetics re-solve these issues. Geogridsprovide reinforcement. Geo-composites provide drainagesupport. And Bentofix® geo-synthetic clay liners provide internal sealing to protect thenoise barrier core. Not onlydoes this enable the use ofmost local materials, it can be used to encapsulate con-taminated soil (e.g., arseniccontaminated soils) while putting it to a beneficial use in infrastructure. The bentonitecore of Bentofix® provides thatenvironmental protection, andthe durable geotextile outerlayers secure the seal even onsteeper barrier slopes.

Bentofix® IQInfrastructure Applications

»All roads lead to Bentofix®«

Fig. 3Freeze-thaw

effects on Bentofix®

permeability.

The IQ of Applications: Resists high water heads, ideal environmental protection, ideal barrier for landfills, versatile sealing applications

Geosynthetics are established in every sector of civil engi-neering. The composite con-struction of geosynthetic clayliners (GCL) reflects howgeosynthetics perform best: byinteracting with natural ele-ments to create somethingstronger or more secure. In thecase of Bentofix® GCLs, the nee-dle-punching of the three layers– outer encapsulating geotex-tiles and intermediate sodiumbentonite core - leads to excel-lent internal and external shearstrength for durability while theuniform layer of sodium ben-tonite provides the contain-ment. Together, these compo-nents outperform significantlythicker compacted clay layers.

Waterproofing:The waterproofing of large infrastructure footprints andstructures is a natural fit forGCLs. The speed and safety ofBentofix® roll installation, andoptions such as the addition of an extra layer of powder

bentonite impregnation on the outer surface of the nonwoven geotextile (Bento-fix® BFG 5000), leads to effi-cient construction and a per-manent, water-tight seal forfloors, slopes, and verticalwalls. Installed against con-crete, Bentofix® seals micro-racks and other flaws found

in conventional hard materialsso that, sealed and protected,the service live of those mate-rials is extended.

Tunnels:In tunneling, geosynthetics are used to seal areas subjectedto high hydraulic pressures aswell as areas of seepage.Bentofix® X2 BFG 5300 servesthis application well. Its extralayer of bentonite, placed

against the structure, providesan intimate seal that will swellquickly and effectively in theevent of water incursion. Andthe extra polymer-coating onthe woven side protects againstthe high water pressure.Secondary containment: Tank farms, such as fuel depots,commonly require secondary

containment geosynthetics. GCLsare significantly cheaper andeasier to install than compactedclay liners; and GCLs, with theirencapsulated, uniform bentonitecores, and the extra polymer-

coating Bentofix® X2 types arefar less prone to the same des-iccation risks than compactedclay layers are. Bentofix® X2types, installed with the poly-mercoated side up, provide ex-ceptional secondary contain-ment and the coating provides

compatibility against a widerange of liquids being stored.

Mining:Few industries are as intensiveand environmentally injurious asmining. When sites are closed,capping systems prevent rainwa-ter incursion into and upwardmigration of potentially harmful

soils and liquids. Bentofix®GCLs provide outstanding envi-ronmental protection and areflexible to accommodate differ-ential settlement. Also, they arenot subject to the elevated

cracking risk of conven-tional clay. Further,Bentofix® is far moreeconomical and envi-ronmentally advanta-geous compared to tra-ditional mineral seals.Clay layers are inexactin thickness, time-con-suming to install andrequire many truckloadsof material; Bentofix® isuniformly thick, quickto install, and requiresonly a fraction of thedelivery traffic. Time

and money are saved, and theenvironmental impact of sitework is minimised.

These are just some samplesof many applications in which the various types of Bentofix®GCLs are being used.

IQ - ApplicationOther Applications

»Never change a winning strategy«

Bentofix® IQOther Applications

Fig. 4Permeability of pre-hydrated Bentofix®GCLs with approx.

4,000 - 5,000 g/m²bentonite) tested

against various liquids and gases

at approx. 30 kN/m²confining stress.

The IQ of Ecology: Reduced energy costs in production, long-lasting designs, low transportation costs; reducing carbon footprint

Bentofix® Thermal Lock geosynthetic clay liners (GCLs) are needle-punched, reinforced composites that combine two durable geo-textile outer layers and a uniform core of high-swelling powder sodium bentonite clay. This construction forms a shear-resistant hydraulic barrier with self-sealing characteristics. When hydrated with fresh water, the bentonite swells and forms a low per-meability gel layer, the hydraulic performance of which is equal to or better than traditional, thick compacted clay liners.

Additionally, the proprietary heat-treating process – Thermal Lock – permanently locks the needle-punched fibres, increases the pull-out resistance of the fibres and ensures long-term shear resistance. Bentofix® GCLs are impregnated with a 500 mm wide, uniform layerof bentonite in both longitudinal directions. This enables an immediately sealed overlap without the need for further bentonite ad-dition on site. Bentofix® BFG is also impregnated with an additional, uniform layer of sodium bentonite powder across its nonwovensurface. This advance is ideally suited for pond and waterproofing applications, since the outer layer of the nonwoven geotextile creates an intimate contact zone in overlap areas, such as with concrete surfaces.

Bentofix® GCLs are part of an important trend toward the combined use of geosynthetics and clay materials in barrier applications as a stand-alone liner system and in the synergistic use of GCLs and geomembranes to maximise liner system efficiency.Bentofix® Thermal Lock GCLs are utilized in but not limited to the following applications: landfill caps and lin-ers; environmental protection under roads, railways, and airports; dam and dyke sealing;vertical barriers; ponds; waterproofing; and secondary containment.

NAUE’s most recent GCL development, Bentofix® X, exemplifieshow modifications to GCL product design can be made to anticipatethe special challenges of a particular site. Bentofix® X is a polyolefinpolymer-coated GCL. The woven fabric is coated with a low-permeabilitypolymeric polyolefin coating to achieve an immediate barrier prior to hydra-tion. Bentofix® X is an advance for GCLs in some specific applications, such aswaterproofing, oil and gas tank farms, landfill capping and cover systems or wherehigh hydraulic gradients are present.

The information contained herein is the best to our knowledge, true and accurate. There is no implied or expressed warranty.© 2011 by NAUE GmbH & Co. KG, Espelkamp-Fiestel, Germany · All rights reserved. · Status 11.02.2011

®

and Bentofix® are registered trademarks of NAUE GmbH & Co. KG.

NAUE GmbH & Co. KGGewerbestrasse 232339 Espelkamp-FiestelGermany

Phone +49 5743 41-0Fax +49 5743 41-240E-Mail info@naue.comInternet www.naue.com

Memberships of the NAUE Group

Member

Member

Member Member

Member MemberMember Member

Member

Member

Member Member MemberMember

Member Member Member

Member

Member

Secugrid® Q6 and R6Bentofix® BFG 5000

Approvals for the NAUE Group

Member