55
Geosynthetic Clay Liners (GCLs) Advances in GCLs Bruno Herlin, P.Eng. Bentofix Product Manager [email protected]
Geosynthetic Clay Liners (GCLs) Advances in GCLs
Bruno Herlin, P.Eng. Bentofix Product Manager [email protected]
Geosynthetic Clay Liners (GCLs) Advances in GCLs
Bruno Herlin, P.Eng. Bentofix Product Manager [email protected]
Geosynthetic Clay Liners (GCLs) Advances in GCLs
Bruno Herlin, P.Eng. Bentofix Product Manager [email protected]
What is a GCL?
Bentonite sandwiched between two layers of textiles GCL = 3 ft of CCL (Compacted Clay Liner).
What is a GCL?
Not every GCL is alike
- Different types for different applications: - Slopes (different textiles used). - Application (ponds vs landfill vs mine site vs base liner vs cap). - Leachate compatibility (bentonite and/or enhanced polymers). - Soil conditions (ion exchange?).
- Different types of bentonites: - Wyoming based bentonite. - Bentonite from overseas (Activated/Soda Ash).
Where to use GCLs:
Geosynthetic Clay Liner
Where to use GCLs:
Geosynthetic Clay Liner
Geosynthetic Clay Liner
Where to use GCLs:
Geosynthetic Clay Liner
Geosynthetic Clay Liner Hydration?
Wyoming based bentonite in direct contact with a Hazardous Leachate
Flux vs time Date Time Flux (m3/m2)/s • March 24, 2017 10:43 AM 8.70E-07 11:15 AM 8.20E-07 12:10 PM 5.10E-07 • March 27, 2017 11:45 AM 7.70E-07 1:19 PM 6.40E-07 12:10 PM 5.10E-07 • March 28, 2017 1:50 PM 7.70E-07 2:02 PM 7.65 E-07 2:12 PM 6.40 E-07
Dry Wyoming bentonite
Wyoming based bentonite in direct contact with a Hazardous Leachate
Enhanced Polymer with a Wyoming Based Bentonite
Foreign based bentonite in direct contact with a Hazardous Leachate
?
Foreign based bentonite in direct contact with a Hazardous Leachate
?
Foreign based bentonite in direct contact with a Hazardous Leachate
?
Foreign based bentonite in direct contact with a Hazardous Leachate
Plate Absorbtion Test – update to ASTM
Time to rename GCLs?
GWCL: Geosynthetic Wyoming Clay Liners GFCL: Geosynthetic Foreign Clay Liners GDL: Geosynthetic Dirt Liners
Over 4+ decades of Wyoming Clay Research Foreign Clay – along for the ride!
Where to use GCLs:
Geosynthetic Clay Liner
Where to use GCLs:
GCL Research / Recent findings
GCLs that are not scrim-reinforced
GCLs that are not scrim-reinforced
Non-Wowen
Bentonite
GCL Cross-Section GCL that is NOT Scrim-Reinforced
Non-Wowen
Woven
Non-Wowen
Bentonite
GCL Cross-Section Scrim-Reinforced GCL
Contains a Scrim (woven)
Non-Wowen
GCL Research / Recent findings GCLs that were Scrim-Reinforced did not Shrink
Benefits of a Scrim-Reinforced GCL
Non-Wowen
Bentonite
Non-Wowen
Benefits of a Scrim-Reinforced GCL
Non-Wowen
Bentonite
Non-Wowen
Woven
Golf Course Pond done with a double nonwoven GCL
Internal Erosion
Why?
USE A THICKER TEXTILE GCL OR BETTER YET – COVER IT UP AS RECOMMENDED!
Coated GCL facing up > No Internal Erosion for 2 yrs in an Exposed Liner Site.
Wrickles of the HDPE
Switch to White HDPE instead of Black HDPE
LessWrinkles = Less Damage during coversoil operations. Less Wrinkes = a lower transmissivity between HDPE/GCL.
Specifying a GCL? Do not use Tradenames
Specifications BENTOFIX ® NSL Thermal Lock® Geosynthetic Clay Liners Bentofix Thermal Lock® NSL Geosynthetic Clay Liner (GCL) is a needlepunched, thermally reinforced composite comprised of a core of natural sodium Wyoming bentonite clay between two durable geotextile layers to form a low permeability hydraulic barrier. The top layer is a staple fiber nonwoven (NW) geotextile while the bottom layer is a woven (W) geotextile. The product is intended for moderate to steep slopes and moderate to high load applications where increased internal shear strength is required.
REMOVE ALL PRODUCT NAMES ASK FOR A TECHNICAL DATA SHEET IN WORD FORMAT
Specifying a GCL? List all the ASTM values
Property ASTM Test Method Frequency Value Imperial Units Value
Metric Units
Typical Geotextile Properties
• Top / Cap Nonwoven • Scrim Reinforced Nonwoven
Bottom Fabric
D 5261
D 5261
200,000 sq ft
( 20,000 m2)
6.0 oz./yd2 MARV
6.0 oz./yd2 MARV
200 g / m2 MARV(1)
200 g / m2 MARV
Bentonite Properties (SI Units Only)
• Swell Index • Moisture Content • Fluid Loss • Smectite (Montmorillonite)
D 5890 D 4643 D 5891
XRD
100,000 lbs. (50,000 kg) 100,000 lbs.
Periodic
24 ml/ 2 g min 12 % max 18 ml max 90% min
24 ml/ 2 g min 12 % max 18 ml max 90% min
Finished GCL Properties
• Bentonite Mass/Unit Area2 • Tensile Strength3 • Peel Strength • Permeability5 • Index Flux5 • Internal Shear Strength6
D 5993
D 6768
D 6496
D 5887
D 5887
D 6243
40,000 ft2 (4,000 m2)
40,000 ft2 (4,000 m2)
40,000 ft2 (4,000 m2)
Weekly
Weekly
Periodic
0.75 lbs/ft2 MARV
45 lb/in MARV
3.5 lbs/in min
5 x 10-9 cm/s max
1 x 10-8 m3/m2/s max
500 psf Typical
3.66 kg/m2 MARV
7.8 kN/m MARV
610 N/m min
5 x 10-9 cm/s max
1 x 10-8 m3/m2/s max
24 kPa Typical
Specifying a GCL? Do not use GRI-GCL3 – which one?
Specifying a GCL? Please don’t go on vacation
before tender closing !
Specifying a GCL? Please don’t go on vacation
before tender closing !
OK … which one do you think he/she will be provided?
4.10.2 GCL Liner: (1) Shall be a needle-punched reinforced composite consisting of two durable geotextile outer layers with a uniform core of natural sodium bentonite clay to form a hydraulic barrier.
Geosynthetic Clay Liner
w=47%
7% initial moisture
Photo: Courtesy of Queens University
GCL Base – 54 weeks HDPE-GCL no cover
w=36%
24% initial moisture
Photo: Courtesy of Queens University
GCL Base – 54 weeks HDPE-GCL no cover
GEOPIPE/GEOTUBES
You can get anything you want
- List all ASTM values and items you want. - DO third party testing (from site samples) … papers mean nothing. - Protect yourself via Third Party Testing.
New products every year – be receptive !
Great new product ! No need for Sandbags/Ballast.
Membership – stay connected.
Thank you for your time …
Bruno Herlin, P.Eng. Product Manager – Terrafix VP Board of Directors, IGS-NA
