Texas Transportation Institute

Since the inception of the Texas Transportation Institute (TTI) in 1993, the facility has conducted extensive testing on various North American Green products to determine acceptance for the Texas Department of Transportation (TXDOT).

Testing conducted by TTI is driven by the conversion of TXDOT from a material-type specification to an approved-products specification, based on the performance of erosion control materials from TTI’s erosion control research.

TXDOT has defined specific performance factors that must be met prior to acceptance of an erosion control product for use in DOT construction or maintenance activities.

TTI evaluates two primary performance factors:

Effectiveness of an erosion control product at protecting the seedbed of an embankment from soil loss during simulated rainfall and runoff
Effectiveness of an erosion control product at promoting vegetation establishment in a single growing season (March through December)

Flexible Channel Liner Testing Protocol

Product testing in this category is conducted on channels with bedslope centerline-gradients of either 3% (produces shear stresses up to 192 Pascal (4 lbs/ft²)) or 7% (produces shear stresses up to 383 Pascal (8 lbs/ ft²)). Prior to any channel testing and product installation, the Manning’s “n” is determined for each product through the use of an indoor flume. After the hydraulic roughness is determined, each flume is seeded and the products are installed according to the manufacturer’s published installation instructions.

After installation, each flume is allowed a 90-day resting period, to allow vegetation establishment.

After 90 days, the flumes are exposed to a series of increased shear stress flows until product failure (due to soil loss) is determined. After each flow, measurements are taken (and recorded) to determine the soil displaced and any physical product movement. The average soil displacement is determined and expressed in centimeters.

Channels are also sampled to determine vegetative growth through the growing season (March – December).

Test Results

Channel Test Data from the Texas Transportation Institute (TTI) for North American Green Erosion Control Blankets

Soil Loss (cm)

Vegetation Density (%)

Channel Test Data from the Texas Transportation Institute (TTI) for North American Green Turf Reinforcement Mattings

Soil Loss (cm)

Vegetation Density (%)

Notes:

North American Green S350 is currently marketed under the SC250 trade name.

North American Green P350 is currently marketed under the P550 trade name.

All content in this section is derived from the publication Final Performance Analysis Through the 2000 Evaluation Cycle Slope Protection Products, Flexible Channel Liner Products & Hydraulic Mulches, co-authored by Paul Northcutt and Jett McFalls.

For additional information on Flexible Channel Liner Testing conducted at TTI, contact North American Green.

We are a proud participant in AASHTO's National Transportation Product Evaluation Program for RECPs.

GSA Contract Number GS-07F-8870D : 04/01/2004-03/31/2009

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