1011.1 Scope. This specification covers geotextile for use in subsurface drainage, sediment control and erosion
control, or as a permeable separator.
1011.2 Acceptance. Acceptance of the material will be based on the manufacturer's certification and upon the
results of such tests as may be performed by the engineer.
1011.3 Material. Geotextiles shall be in accordance with the physical and chemical requirements of AASHTO
M 288 for the specified application, except as modified in this specification.
1011.3.1 Subsurface Drainage Geotextile. Subsurface drainage geotextile shall be used in subsurface drainage
as a filter to protect drainage media from clogging with fines from adjacent soil. Typical applications include the lining of drainage trenches and the wrapping of drainpipes.
1011.3.1 1 The minimum permittivity shall be 1.0 sec-1.
1011.3.1 2 The material shall be AASHTO Class 2.
1011.3.2 Temporary Silt Fence Geotextile. Temporary silt fence geotextile shall be used in supported or non-
supported sediment control fencing.
1011.3.3 Permanent Erosion Control Geotextile. Permanent erosion control geotextile shall be used when the
erosion control measure will not be removed, such as erosion control of slopes and channels when placed under a rock blanket, rock ditch liner, etc.
1011.3.3 1 The minimum permittivity shall be 1.0 sec-1.
1011.3.3 2 The material shall be either AASHTO Class 1 or Class 2.
1011.3.4 Separation Geotextile. Separation geotextile shall be used as a separation material to prevent mixing
of dissimilar material, and to control migration of backfill material through joints in structural elements.
1011.3.4 1 The minimum permittivity shall be 1.0 sec-1.
1011.3.4 2 The material shall be AASHTO Class 1.
1011.3.5 Erosion Control Blankets. Erosion control blankets (ECB) shall be categorized based on performance
testing for the C-factor by ASTM D6459 and physical testing for the minimum tensile strength by ASTM D5035. Erosion control blankets shall meet the following requirements. ECB Type Description Material Composition Longevity Max Slope C- factor Minimum Tensile Strength 1.A Mulch Control Nets A photodegradable synthetic mesh or woven biodegradable natural fiber netting 3 months 5:1 ≤ 0.10 @ 5:1 5 lb/ft 1.B Netless Rolled Erosion Control Blankets Natural and/or polymer fibers mechanically interlocked and/or chemically adhered together to form an RECP 3 Months 4:1 ≤ 0.10 @ 4:1 5 lb/ft 1.C Light-Weight Double-Net Erosion Control Blankets Natural and/or polymer fibers mechanically bound together by two rapidly degrading, synthetic or natural fiber netting 3 months 3:1 ≤ 0.15 @ 3:1 50 lb/ft 1.D Heavy Double- Net Erosion Control Blankets Processed degradable natural and/or polymer fibers mechanically bound together between two rapidly degrading, synthetic or natural fiber nettings 3 months 2:1 ≤ 0.20 @ 2:1 75 lb/ft 2.A Mulch Control Nets A photodegradable synthetic mesh or woven biodegradable natural fiber netting 12 months 5:1 ≤ 0.10 @ 5:1 5 lb/ft 2.B Netless Rolled Erosion Control Natural and/or polymer fibers mechanically interlocked and/or chemically adhered together to form an RECP 12 months 4:1 ≤ 0.10 @ 4:1 5 lb/ft 2.C Light-Weight Double-Net Erosion Control Blankets Natural and/or polymer fibers mechanically bound together by two degrading, synthetic or natural fiber netting 12 months 3:1 ≤ 0.15 @ 3:1 50 lb/ft 2.D Heavy Double- Net Erosion Control Blankets Processed degradable natural and/or polymer fibers mechanically bound together between two degrading, synthetic or natural fiber netting 12 months 2:1 ≤ 0.20 @ 2:1 75 lb/ft 3.A Mulch Control Nets A slow degrading synthetic mesh or woven natural fiber netting 24 months 5:1 ≤ 0.10 @ 5:1 25 lb/ft 3.B Erosion Control Blankets An erosion control blanket composed of processed slow degrading natural or polymer fibers mechanically bound together between two slow degrading synthetic or natural fiber nettings to form a continuous matrix 24 months 1.5:1 ≤ 0.25 @ 1.5:1 100 lb/ft 4 Erosion Control Blankets An erosion control blanket composed of processed slow degrading natural or polymer fibers mechanically bound together between two slow degrading synthetic or natural fiber nettings to form a continuous matrix 36 months 1:1 ≤ 0.25 @ 1:1 125 lb/ft
1011.3.5 1 Anchors. Anchors as recommended by the erosion control product manufacturer shall be used.
1011.3.5 2 Test Methods.
1011.3.5 2.1 ASTM D6459 testing shall be performed on loam soil. The calculated C-factor for the tested slope
shall be determined from the reported C-factor regression equation using an erosivity value of 224. Type 1.A, Type 2.A, and Type 3.A mulch control nets must be tested in conjunction with pre-applied mulch material. Minimum tensile strength shall be tested in accordance with ASTM D5035 in the machine direction.
1011.3.5 2.2 Texas Department of Transportation and the Texas Transportation Institute testing for product
acceptance on 3:1 or 2:1 sand may be substituted for acceptance of ASTM D6459 on loam soil.
1011.3.5 3 Pre-Qualification List: Prior to use, the manufacturer shall furnish a manufacturer’s certification to
the Construction and Materials division stating the name of the manufacturer, the chemical composition of the filaments or yarns and certifying that the material supplied is in accordance with this specification. The certification shall include recent results of tests for all specified requirements. Final acceptance of erosion control blankets will be based on certification and field performance.
1011.3.5 4 Acceptance. Final acceptance of erosion control blankets will be based on the erosion control
blankets being utilized as pre-qualified and actual field performance.
1011.3.6 Turf Reinforcement Mats. Turf reinforcement mats (TRM) shall be certified by the manufacturer for
open flow channels and shall meet the following calculated shear stress: TRM TypeCalculated Shear Stress (lbs/ft2) Type 1 3.5 – 6 Type 2 6.1 – 8 Type 3 8.1 – 10 Type 4 10.1 or greater
1011.3.6 1 Anchors. Anchors as recommended by the product manufacturer shall be used.
1011.3.6 2 Test Methods. Turf reinforcement mats tested and evaluated by either ASTM D6460 or by the Texas
Department of Transportation and Texas Transportation Institute independent testing. The test results must indicate the maximum allowable shear strength. ASTM D6460 shall be tested on the loam soil.
1011.3.6 3 Pre-Qualification List: Prior to use, the manufacturer shall furnish a manufacturer’s certification to
the Construction and Materials division stating the name of the manufacturer, the chemical composition of the filaments or yarns and certifying that the material supplied is in accordance with this specification. The certification shall include recent results of tests for all specified requirements. Final acceptance of turf reinforcement mat will be based on certification and field performance.
1011.3.6 4 Acceptance. Final acceptance of turf reinforcement mats will be will be based on the turf
reinforcement mat being utilized as pre-qualified and actual field performance.
1011.3.7 Unbonded Concrete Overlay Interlayer. Unbonded concrete overlay interlayers shall have the
following material properties: Property Requirement Test Method Fabric Type Non-woven Geotextile Mass per unit area Min. 14.8 oz/sq.yd ASTM D 5261 Thickness under load (pressure) 0.29 psi: ≥ 0.12 in 2.9 psi: ≥ 0.10 in 29 psi: ≥ 0.04 in ASTM D 5199, modified under loads of 0.29, 2.9, and 29 psi Tensile strength ≥ 685 lb/ft ASTM D 4595 Maximum elongation ≤ 130% ASTM D 4595 Water permeability in normal direction under load (pressure) ≥ 3.3×10-4 ft/s [under pressure of 2.9 psi] ASTM D 5493 Water permeability in the plane direction of the fabric (transmittivity) under load (pressure) ≥ 1.6×10-3 ft/s [under pressure of 2.9 psi] ≥ 6.6×10-4 ft/s [under pressure of 29 psi] ASTM D 6574 Weather resistance Resistance ≥ 60% EN 12224 Alkali resistance ≥ 96% Polypropylene/Polyethylene
1011.4 Certification. The contractor shall furnish a manufacturer's certification to the engineer for each lot of
material furnished stating the name of the manufacturer, the chemical composition of the filaments or yarns and certifying that the material supplied is in accordance with this specification. The certification shall include or have attached typical results of tests from specific lots for all specified requirements.
Geotextile in other states
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