Large-Scale Slope Erosion Testing (ASTM D 6459 …

1 Large-Scale Slope Erosion Testing ( astm D 6459 modified) of GeoSkin XT over Sandy Loam August 2011 Submitted to: AASHTO/NTPEP 444 North Capitol Street, NW, Suite 249 Washington, 20001 Attn: Evan Rothblatt, NTPEP Submitted by: TRI/Environmental, Inc. 9063 Bee Caves Road Austin, TX 78733 C. Joel Sprague Project Manager August 19, 2011 Mr. Evan Rothblatt AASHTO/NTPEP 444 North Capitol Street, NW, Suite 249 Washington, 20001 E-mail: Subject: Large-Scale Slope Testing of GeoSkin XT over Sandy Loam Dear Mr.

2 Rothblatt: This letter report presents the results for Large-Scale Slope Erosion tests performed on GeoSkin XT hydraulically-applied Erosion control product (HECP) over sandy loam. All Testing work was performed in general accordance with the astm D 6459, Standard Test Method for Determination of Rolled Erosion Control Product (RECP) Performance in Protecting Hillslopes from Rainfall-Induced Erosion modified as necessary to accommodate hydraulically-applied mulch. The product was allowed to cure on the slopes for approximately 48 hours prior to Testing .

3 Generated results were used to develop the following general cover factor (C-Factor) for the tested material: C-Factor GeoSkin XT @ 2000lbs/acre = for cumulative R Factor < 231 Eqn: C = TRI is pleased to present this final report. Please feel free to call if we can answer any questions or provide any additional information. Sincerely, C. Joel Sprague, Senior Engineer Geosynthetics Services Division Cc: Sam Allen, Jarrett Nelson - TRI GeoSkin XT HECP over Sandy Loam Slope Erosion Testing for NTPEP August 19, 2011 2 Slope Testing REPORT GeoSkin XT HECP over Sandy Loam Testing EQUIPMENT AND PROCEDURES Overview of Test and Apparatus TRI/Environmental, Inc.

4 's (TRI's) Large-Scale Slope Erosion Testing facility is located at the Denver Downs Research Farm in Anderson, SC. Testing oversight is provided by C. Joel Sprague, The Large-Scale Testing reported herein was performed in accordance with astm D 6459 modified as necessary to accommodate hydraulically-applied mulch, on 3:1 slopes using loamy soil test plots measuring 40 ft long x 8 ft wide. The simulated rainfall was produced by ten rain trees arranged around the perimeter of each test Slope .

5 Each rain tree has four sprinkler heads atop a 15 ft riser pipe. The rainfall system has been calibrated prior to Testing to determine the number of sprinkler heads and associated pressure settings necessary to achieve target rainfall intensities and drop sizes. The target rainfall intensities are 2, 4, and 6 in/hr and are applied in sequence for 20 minutes each. Three replicate test slopes covered by the same hydraulically-applied Erosion control product (HECP) submitted were tested.

6 The application rate of the HECP was 2000 lb/acre. The product was allowed to cure on the slopes for approximately 48 hours prior to Testing . The Erosion resistance provided by the product tested is obtained by comparing the protected Slope results to control (bare soil) results. Tables and graphs of rainfall versus soil loss are generated from the accumulated data. Hydraulic Erosion Control Product (HECP) The following information and index properties were determined from the supplied products.

7 Table 1. Tested Product Information & Index Properties Product Information and Index Property / Test Units Sampled Product Product Identification - GeoSkin XT Manufacturing Plant Location - Centre, AL Lot number of sample - 2 Bags: lot 1A-4-27-11; 2 Bags: lot A-4-28-11; 1 Bag: lot 2A-4-26-11 Mechanically Processed Straw % 73% 3% Mechanically Processed Reclaimed Cottom Plant Material % 14% 3% Proprietary Blend of Tackifiers, Activitors and Additives % < 1% Moisture % 12% 3% Tensile Strength ( astm D 6818 modified)* lb/in N/A Tensile Elongation ( astm D 6818 modified)* % N/A Thickness ( astm 6525 modified)* mils 136 Light Penetration ( astm 6567 modified)* % cover Water Absorption ( astm 1117 / ECTC TASC 00197)* % Wt Change N/A Mass / Unit Area ( astm D 6566 modified)* osy Note.

8 Index specimens were made using the currently proposed astm procedure. N/A = not applicable because suitable specimens could not be made using the currently proposed astm procedure. * Values from Independent Testing of Randomly Sampled Product GeoSkin XT HECP over Sandy Loam Slope Erosion Testing for NTPEP August 19, 2011 3 Test Soil The test soil used in the test plots had the following characteristics. Table 2. TRI-Loam Characteristics Soil Characteristic Test Method Value % Gravel astm D 422 0 % Sand 45 % Silt 35 % Clay 20 Liquid Limit, % astm D 4318 41 Plasticity Index, % 8 Soil Classification USDA Sandy Loam Soil Classification USCS Sandy silty clay (ML-CL) K-Factor D 6459 Preparation of the Test Slopes The initial Slope soil veneer (12-inch thick minimum) is placed and compacted.

9 Compaction is verified to be 90% ( 3%) of Proctor Standard density using astm D 1556 (sand cone method). Subsequently, the test slopes undergo a standard preparation procedure prior to each Slope test. First, any rills or depressions resulting from previous Testing are filled in with test soil and subject to heavy compaction. The entire test plot is then tilled to a depth not less than four inches. The test Slope is then raked to create a Slope that is smooth both side-to-side and top-to-bottom.

10 Finally, a steel drum roller is rolled down-and-up the Slope 3 times proceeding from one side of the plot to the other. The submitted Erosion control product is then installed using the spray technique acceptable to the client. For this Testing , TRI applied the product to the slopes. Installation of Erosion Control Product on Test Slopes As noted, the submitted Erosion control product was installed as directed by the client. For the tests reported herein, the GeoSkin XT was applied at the rate of 2000 lb/acre.