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.