Road Construction

Geotextile DOT Information

road construction, geotextile, highway The use of geotextiles in road construction is no mystery. The geotextiles act as separators, filters, and stabilizers. The following tables display standard specifications for woven and non-woven geotextiles used for highway applications. The specifications are based on geotextile survivability from installation stresses.


Geotextile Strength Property Requirements:
Test Methods
Class 1 Elongation <50%
Class 1 Elongation ≥50%
Class 2 Elongation <50%
Class 2 Elongation ≥50%
Class 3 Elongation <50%
Class 3 Elongation ≥50%
Grab Strength
ASTM D4632
1400
900
1100
700
800
500
Sewn Seam Strength
ASTM D4632
1260
810
990
630
720
450
Tear Strength
ASTM D4533
500
350
400
250
300
180
Puncture Strength
ASTM D4833
500
350
400
250
300
180

Subsurface Drainage Requirements:

Geotextile Class 2
Test Methods
Units
% In Situ Soil Passing 0.075 mm <15
% In Situ Soil Passing 0.075 mm 15-50
% In Situ Soil Passing 0.075 mm >50
Permittivity
ASTM D4491
sec -1
0.5
0.2
0.1
Apparent Opening Size
ASTM D4751
mm
0.43
0.25
0.22
Ultraviolet Strength
(Retained Strength)
ASTM D4355
%
50% after 500 hours of Exposure
50% after 500 hours of Exposure
50% after 500 hours of Exposure

Description: This specification is applicable to placing a geotextile against a soil to allow for long-term passage of water into a subsurface drain system retaining the in situ soil for road construction.

Note: Woven Silt Film Geotextiles are not allowed.

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Separation Requirements:

Geotextile Class 2
Test Methods
Units
Requirements
Permittivity
ASTM D4491
sec -1
0.02
Apparent Opening Size
ASTM D4751
mm
0.60
Ultraviolet Strength
(Retained Strength)
ASTM D4355
%
50% after 500 hours of Exposure

Description: This specification is applicable to the use of a geotextile to prevent the mixing of a subgrade soil and an aggregate cover material. The separation application is appropriate for pavement structures constructed over soils with a California Bearing Ratio equal to or greater than 3 and unsaturated subgrade soils.

Stabilization Requirements:

Geotextile Class 1
Test Methods
Units
Requirements
Permittivity
ASTM D4491
sec -1
0.05
Apparent Opening Size
ASTM D4751
mm
0.43
Ultraviolet Strength
(Retained Strength)
ASTM D4355
%
50% after 500 hours of Exposure

Description: This specification is applicable to the use of a geotextile in wet, saturated conditions to provide the coincident functions of separations and filtration. In some installations, the geotextile can also provide the function of reinforcement. Stabilization for road construction is applicable to pavement structures constructed over soils with a California Bearing Ratio between one and three.

The stabilization application is appropriate for subgrade soil that are saturated due to a high groundwater table of due to prolonged periods of wet weather.

Note:This specification is not appropriate for embankment reinforcement where stress conditions may cause global subgrade foundation or stability failure during road construction.

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Permanent Erosion Control Requirements:

Geotextile Class 1 & 2
Test Methods
Units
% In Situ Soil Passing 0.075 mm <15
% In Situ Soil Passing 0.075 mm 15-50
% In Situ Soil Passing 0.075 mm >50
Permittivity
ASTM D4491
sec -1
0.7
0.2
0.1
Apparent Opening Size
ASTM D4751
mm
0.43
0.25
0.22
Ultraviolet Strength
(Retained Strength)
ASTM D4355
%
50% after 500 hours of Exposure
50% after 500 hours of Exposure
50% after 500 hours of Exposure

Description: This specification is applicable to the use of a geotextile between energy absorbing armor systems and in the in situ soil to prevent soil loss resulting in excessive scour and to prevent hydraulic uplift pressures causing instability of the permanent erosion control system.

Note: This specification does not apply to other types of geosynthetic soil erosion control materials such as turf reinforcement mats and Woven Slit Film Geotextiles are not allowed.

Temporary Silt Fence Requirements:
Test Methods
Units
Supported Silt Fence
Unsupported Silt Fence Elongation ≥50%
Unsupported Silt Fence Elongation <50%
Maximum Post Spacing
1.2 m
1.2 m
2 m
Grab Strength
ASTM D4632
N
Machine Direction
400
550
550
X-Machine Direction
400
450
450
Permittivity
ASTM D4491
sec-1
0.05
0.05
0.05
Apparent Opening Size
ASTM D4751
mm
0.60
0.60
0.60
Ultraviolet Stability
(Retained Strength)
ASTM D4355
%
70% after 500 hrs of exposure
70% after 500 hrs of exposure
70% after 500 hrs of exposure

Description: This specification is applicable to the use of a geotextile as a vertical, permeable, interceptor designed to remove suspended soil from overland water flow.

Note: The geotextile used for temporary silt fence may or may not be supported between posts with wire or polymeric mesh. The minimum height is 750 mm. Minimum embedment depth is 150 mm.

Paving Fabric Requirements:
Test Methods
Units
Requirements
Grab Strength
ASTM D4632
N
450
Ultimate Elongation
ASTM D4632
%
≥50
Mass per Unit Area
ASTM D5261
gm/m2
140
Asphalt Retention
ASTM D6140
l/m2
See Notes Below
Melting Point
ASTM D276
°C
150

Description: This specification is applicable to the use of a paving fabric, saturated with asphalt cement, between pavement layers. The function of the paving fabric is to act as a waterproofing and stress relieving membrane within the pavement structure.

Note: Asphalt required to saturate paving fabric only. Asphalt retention must be provided in manufacturer certification. Product asphalt retention property must meet the MARV value provided by the manufacturer certification.

Questions? We can help! Call our team at +1-772-646-0597 or submit a form.