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GRI-GM 28 Specification - for -
Scrim Reinforced Chlorosulfonated Polyethylene (CSPE-R) Geomembranes
• silent on method of manufacturing
• only addresses scrim reinforced product
• silent on type and weave of scrim
• three thickness categories as follows: 36, 45 and 60 mils (0.91, 1.14 and 1.52 mm)
• lists eleven properties, test methods, test values and testing frequency
Regarding the Resin
• originally a duPont patented resin
• good performance record when exposed, e.g., many floating pond covers
• duPont ceased production in ca. 2010
• many permits still require this resin
• all CSPE resin is currently imported to U.S.
• questions arise as to quality and consistency
• hopefully, this spec satisfies the need
Required Material Properties
Physical Properties
1. mass/unit area
Mechanical Properties
3. tensile strength (grab)
4. tensile elongation (grab)
5. tear resistance (tongue)
6. puncture resistance
Endurance Properties
11. ultraviolet light resistance
2. thickness
7. ply adhesion
8. low temp.-flexibility
9. dimensional stability
10. carbon black content
1. Mass per Unit Area
• usually called “weight”
• follows ASTM D5261
• five specimens across roll width
• values averaged and compared to spec value stated as “min. ave.”
• required every 15,000 lb (7,500 kg)
ASTM D5261 Mass/Unit Area (Weight) Test
2. Thickness
• follows ASTM D5199
• dead weight micrometer with flat tip
• measurement includes the scrim
• 10-specimens across roll width
• average must equal of nominal
• lowest individual is -10% nominal
• min. ave. values are listed
• required for each roll
ASTM D5199 Thickness Test
3&4. Grab Tensile Strength and Elongation
• follows ASTM D7004
• 4 in. (100 mm) wide specimen grabbed in the central 1 in. (25 mm)
• data reported in lb (or N), not lb/in. (or N/m)
• min. ave. of both 5 MD and 5 XMD
• required every 15,000 lb (7,500 kg)
ASTM D7004 – Grab Tensile Test (Measures Strength and Elongation)
5. Tear Resistance
• uses ASTM D5884 (tongue method)
• specimen 8 4 in. with 3 in. slit (200 100 mm with 75 mm slit)
• speed is 2.0 in./min (50 mm/min)
• average of 5MD and 5XMD
• required every 15,000 lb (7,500 kg)
D5884 Tongue Tear
6. Puncture Resistance
• follows ASTM D4833
• called “pin” puncture
• correlates well to CBR puncture
• min. ave. of 15-tests
• required every 15,000 lb (7,500 kg)
D4833 “Pin”
Puncture Test
7. Ply Adhesion
• follows ASTM D6636
• min. ave. of 5 longitudinal tests
• requires 20 lb (9 N) min. ave.
• required every 30,000 lb (15,000 kg)
Ply Adhesion per ASTM D6636
8. Low Temperature Flexibility
• follows ASTM D2136
• incubation in environmental chamber at -40°F (-40°C) for 4 hrs.
• specimen bent around 1.8 in. (3.2 mm) mandrel
• no visible cracks or crazes
• required once per formulation
Low Temperature Controlled Chamber
9. Dimensional Stability
• follows ASTM D1204
• uses two 10 10 in. (25 25 cm) specimens
• one from edge, other from center
• heat incubated at 100°C for one hour
• percent maximum change is 2.0%
• required once per formulation
D721 Forced Air
Oven
10. Carbon Black Content
• follows ASTM D4218 (muffle furnace)
• alternative is D1603 (combustion boat)
• only for black geomembranes
• acceptable value is from 5-30%
• lower value when fillers added
• required every 45,000 lb (22,000 kg)
Muffle Furnace D4218
Combustion Boat in Tube Furnace
D1603
11. Ultraviolet Resistance
• follows ASTM D7238
• called “ultraviolet fluorescent device”
• 20 hr. UV cycle at 75°C, then 4 hr. condensation at 60°C per daily cycle
• 50% strength or 50% elongation retained after 20,000 lt. hrs.
• also, no cracking or only minor chalking (GRI-GM16)
• frequency is per formulation
ASTM D7238 Ultraviolet
Fluorescent Weatherometer
Concluding Comments
• spec addresses scrim reinforced CSPE-R
• three thicknesses are listed
• material is often used exposed (and covered)
• endurance properties are critical
• this is an MQC specification; if manufacturer’s QC is more stringent use it, if not use this specification
The Basic Tables Follow
1(a) - U.S. Standard Units
1(b) – SI (Metric) Units
Note: The most recent version of this specification (text and tables) is available on the GSI Web Site
http://www.geosyntheticinstitute.org/specifications.htm
Property Test Method ASTM or GRI
CSPE-R 36 mils
CSPE-R 45 mils
CSPE-R 60 mil
Testing Frequency (minimum)
Mass per Unit Area – lb/ft2 (min. ave.) D5261 0.15 0.18 0.24 15,000 lb
Thickness – mils (min. ave.) lowest individual specimen – mils, nominal – 10%
D5199 36 32
45 40
60 54
per roll or panel
Tensile Strength(1) grab(1) – lb (min. ave.)
D7004
200
250
300
15,000 lb
Tensile Elongation(2) grab - % (min. ave.)
D751-A
15
15
15
15,000 lb
Tear Resistance(1) reinforced – lb (min. ave.)
D5884
70
70
70
15,000 lb
Puncture Resistance – lb (min. ave.) D4833 75 85 100 15,000 lb
Ply Adhesion – lb (min. ave.) D6636 15 15 15 15,00 lb
Low Temperature Flexibility - F D2136(3) -40 -40 -40 per formulation
Dimensional Stability - % change max. D1204(4) 2 2 2 per formulation
Carbon Black Content(5) - % D4218 5-36 5-36 5-36 45,000 lb
Ultraviolet Light Resistance(5,6) (a)Surface Cracking Observation after 20,000 light hrs. (b)Surface Chalking (or Powdering) after 20,000 light hrs. (c) % strength retained after 20,000 light hrs. - or - (d) % elongation retained after 20,000 light hrs.
D7238 GM16 GM23
D6693-IV
D6693-IV
none minor 50
50
per formulation
Table 1(a) – Reinforced Chlorosulphonated Polyethylene (CSPE-R) Geomembranes
U. S. Standard Units
(1) Test methods modified to 12 in./min. for reinforced material (2) Calculation based on a 3.0 in. gage length (3) Using 1/8 in. mandrel for 4-hours. (4) Incubated at 100°C 1°C for one hour. (5) Applicable only to black geomembranes. Also D1603 is an acceptable method to determine carbon black content. (6) The conditions of the UV Fluorescent exposure method should be 20 hr. UV cycle at 75°C followed by 4 hr. condensation at 60 C. (7) See Section 5.2 for fPP-R geomembranes.
Reinforced
Non-Reinforced
Property Test Method ASTM or GRI
CSPE-R 0.91 mm
CSPE-R 1.14 mm
CSPE-R 1.52 mm
Testing Frequency (minimum)
Mass per Unit Area – kg/m2 (min. ave.) D5261 0.73 0.88 1.17 7500 kg
Thickness – mils (min. ave.) lowest individual specimen – mils, (nominal – 10%)
D5199 0.91 0.82
1.14 1.03
1.52 1.37
per roll or panel
Tensile Strength grab(1) – N (min. ave.)
D7004
890
1110
1340
7500 kg
Tensile Elongation grab(1) - % (min. ave.)
D751-A
15
15
15
7500 kg
Tear Resistance reinforced(1) – N (min. ave.)
D5884
315
315
315
7500 kg
Puncture Resistance – N (min. ave.) D4833 330 380 440 7500 kg
Ply Adhesion – N (min. ave.) D6636 65 65 65 7500 kg
Low Temperature Flexibility - C D2136(3) -40 -40 -40 per formulation
Dimensional stability - % change max. D1204(4) 2 2 2 per formulation
Carbon Black Content(5) - % D4218 5-36 5-36 5-36 22,000 kg
Ultraviolet Light Resistance(5,6) (a) Surface Cracking Observation after 20,000 light hrs. (b) Surface Chalking (or Powdering) after 20,000 light hrs. (c) % strength retained after 20,000 light hrs. - or - (d) % elongation retained after 20,000 light hrs.
D7238 GM16 GM23
D6693-IV
D6693-IV
none minor 50
50
per formulation
Table 1(b) – Reinforced Chlorosulphonated Polyethylene (CSPE-R) Geomembranes
SI (Metric) Units
Reinforced
Non-Reinforced
(1) Test methods modified to 500 mm/min. for unreinforced and 12 in./min. for reinforced material (2) Calculation based on a 50 mm gage length (3) Using 3.2 mm mandrel for 4-hours. (4) Incubated at 100°C 1°C for one hour. (5) Applicable only to black geomembranes. Also D1603 is an acceptable method to determine carbon black content. (6) The conditions of the UV Fluorescent exposure method should be 20 hr. UV cycle at 75C followed by 4 hr. condensation at 60C. (7) See Section 5.2 for fPP-R geomembranes.