GEOSYNTHETICS
PART 1 GENERAL
1.1SECTION INCLUDES
A.Geosynthetics for subgrade stabilization and base reinforcement.
1.2RELATED SECTIONS
A.Section 02075: Geotextiles
1.3REFERENCES
A.ASTM D 374: Thickness of Solid Electrical Insulation
B.ASTM D 4355: Deterioration of Geotextiles by Exposure to Light, Moisture
and Heat in a Xenon Arc-Type Apparatus
C.ASTM D 4759: Determining the Specification Conformance of Geosynthetics
D.ASTM D 5818: Exposure and Retrieval of Samples to Evaluate Installation
Damage of Geosynthetics
E.ASTM D 6637: Determining Tensile Properties of Geogrids by the Single or
Multi-rib Tensile Method
F.ASTM D 7737: Individual Geogrid Junction Strength
G.ASTM D 7748: Flexural Rigidity of Geogrids, Geotextiles and Related
Products
H.ASTM D 7864: Determining the Aperture Stability Modulus of Geogrids
1.4DEFINITIONS
A.Geogrid – A biaxial polymeric grid formed by a regular network of integrally
connected tensile elements with apertures of sufficient size to allow interlocking with surrounding soil, rock, or earth to function primarily as reinforcement.
Geosynthetics
B.Geosynthetic Composite System – A system of geogrid for reinforcement and
confinement of the base course material along with a separation geotextile or approved alternate systems.
C.Minimum Average Roll Value (MARV) – Reported value of a property taken as
two standard deviations below the population mean based on testing and determined according to ASTM D 4759 to verify that the product meets specification requirements.
1.5SUBMITTALS
A.APL Compliance Form for information is required for the following products.
1.Geosynthetic Composite System
2.Alternative Geosynthetic Composite Systems
B.Manufacturer’s product data sheets and recommended installation
instructions.
1.6ACCEPTANCE
A.The Department rejects material at installation if it has defects, rips, holes,
flaws, deterioration, or damage incurred during manufacture, transport, handling or storage.
1.7PACKAGING, SHIPPING AND STORING
A.Labeling and Tagging
1.Identify each package by a tag or label securely affixed to the outside of
the roll on at least one end.
2.Provide the following required information on the tag:
a.Name of the geotextile manufacturer
b.Brand name of the product
c.Width, length, and package weight
d.Roll number(s)
e.Lot number(s)
B.Storage and Protection.
1.Prevent excessive mud, wet concrete, epoxy, or other deleterious
materials from coming in contact with and affixing to the geosynthetic materials.
2.Store at temperatures above -20 degrees F and below 140 degrees F.
3.Rolled materials may be laid flat or stood on end.
4.Do not expose geosynthetic materials to direct sunlight for a period
longer than recommended by the manufacturer.
5.Keep geosynthetic materials dry until installation.
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PART 2 PRODUCTS
2.1GEOSYNTHETIC COMPOSITE SYSTEM
A.Geogrids.
1.Meet the requirements of Table 1.
Table 1 Geogrid Property Requirements Property Test Method Value3 Aperture size (in) nominal ASTM D 374 1.0 (MD) x 1.3 (XMD) dimension Rib Thickness (in) ASTM D 374 0.05 Junction Thickness (in) ASTM D 374 0.120 Junction efficiency, % of rib ultimate ASTM D 7737 Method 93% tensile strength1 (min.) A Tensile strength, 2% strain (lb/ft) ASTM D 6637 Method 410 (MD) x 620 (XMD) B Geosynthetic Sheet ASTM D 6637 Method 2,500 (XMD)2 Stiffness/Modulus (lbs/in)(min.) B Ultimate Strength (lb/ft) ASTM D 6637 Method 1,310 (MD) x 1,970 B (XMD) Ultraviolet resistance (%) minimum ASTM D 4355 70 retained tensile strength after 500 hours Flexural stiffness (mg-cm) ASTM D 7748 750,000 Aperture Stability (kg-cm/deg) ASTM D 7864 6.5 Note:
1.Junction efficiency is the ratio of (ASTM D7737 Junction Strength) / (ASTM D 6637
Method “A” Single Rib) x 100
2.Sheet stiffness/modulus value = Tensile Strength @ 2% strain ÷ 0.02 ÷ 12
3.Minimum Average Roll Values (MARVs) in accordance with ASTM 4759
4.Machine Direction (MD) Cross Machine Direction (XMD)
5.Independent testing shall be performed by an accredited laboratory through the
Geosynthetic Accreditation Institute-Laboratory Accreditation Program.
B.Separation Geotextile.
1.Refer to Section 02075.
Geosynthetics
2.2ALTERNATIVE GEOSYNTHETIC COMPOSITE SYSTEMS
A.Alternative geosynthetic composite systems not on the APL may be used if
approved.
1.Approval will be based on full scale laboratory testing or field testing of
the alternate system immediately adjacent to and within 50 ft of a baseline composite system using materials meeting the criteria in Article 2.1.
a.Test two different pavement sections with each system.
1) Aggregate Base Course (minimum 6 inch), Geosynthetic composite system, subgrade (Modulus 5 to 25 ksi). 2) Aggregate Base Course (minimum 6 inch), Geosynthetic composite system, Stabilizing Material (minimum 6 inch), Geosynthetic composite system, subgrade (Modulus 0.55 to 5 ksi).
b.Submit composite resilient modulus values from both systems.
c.Submit deformation values for both systems.
d.The alternate system performance must meet or exceed the
baseline composite system performance.
PART 3 EXECUTION
3.1INSTALL GEOSYNTHETIC COMPOSITE SYSTEM
A.Orient the geosynthetic rolls parallel to the roadway centerline. Use widths
that produce overlaps of parallel rolls at the centerline and shoulders.
B.Geosynthetic Composite System
1.Separation Geotextile.
a.Install the separation component under the reinforcement
component if the system is two separate products.
b.Meet the Installation requirements of Section 02075.
2.Geogrid.
a.Provide minimum overlap according to manufacturer’s
recommendations.
b.Install geogrid according to the guidelines provided by the
manufacturer or as directed by the Engineer.
3.Alternate Geosynthetic Composite System.
a.Follow manufacturer’s recommendations.
C.Temporarily secure the geosynthetics in place using ties, staples, pins, sand
bags or backfill, or as determined by the Engineer.
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D.Place, spread, and compact granular fill material in such a manner that
minimizes the development of wrinkles in or movement of the geosynthetic composite system.
E.Do not operate vehicles over the geosynthetic composite system until at least
six inches of loose fill has been placed.
1.Keep the turning of vehicles to a minimum to prevent vehicles from
displacing the fill and damaging the geosynthetic system.
F.Replace any roll of geosynthetic damaged before, during, or after installation.
1.Replace the affected area and overlap the geosynthetic one foot on all
sides adjacent to the damaged area.
2.Follow ASTM D 5818 for exposure and retrieval of damages done
during installation of evaluation samples.
END OF SECTION
Geosynthetics
Geosynthetics in other states
Utah revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.
Source: Utah Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 242–246 of 1,331.
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