mattresses to achieve proper alignment. Class 2 is
allowed where no vehicle traffic will occur on the
installation, and where mattress placement is in
regular, even reaches. Reference Protection of Work
paragraph in Part 3.
Some manufactures require minimum geotextile
properties for warranty coverage. Most
manufacturers have recommended geotextiles, but
these should be verified for compatibility with the
subgrade soils.
Filters should not impede seepage. Clogging
resistance is critical for uplift stability. Site
specific design should be performed if any of the
following problematic soil conditions are
encountered: highly erodible soils such as
non-cohesive silts, gap graded soils, or laminated
sand/silt.
Some references for geotextile design include:
1. Koerner, "Designing with Geosynthetics",
Prentice Hall.
2. FHWA, "Geosynthetic Design and Construction
Guidelines."
3. Geosynthetics '95, "Geotextile Permeability
Criteria for Revetments", pp. 217-230.
Geosynthetic Selection - The Federal Acquisition
Regulations require full and open competition.
Usually justification is not necessary if 3 products
meet the specifications. In combining various
material requirements, it is easy to specify a
geosynthetic product that does not exist. Design
utilizing geosynthetics should include a listing
with the calculations that verify the specified
products are commercially available. The
Geotechnical Fabrics Report magazine publishes an
annual specifiers guide that is ideal for this
purpose.
**************************************************************************
Geotextile used as filters below the ACB shall be a [woven] [non-woven]
fabric. The geotextile shall meet the material properties specified in
AASHTO M 288 for Class [2] strength property requirements and for permanent
erosion control. Filter requirements in AASHTO M 288 shall be based on
in-situ soil with [less than 15%] [15% to 50%] [greater than 50%] passing
the 0.075 mm sieve opening.
SPECIFIC=GEOTEXTILE> SPECIFIC=GEOTEXTILE>
SPECIFIC=GEOTEXTILE> SPECIFIC=GEOTEXTILE> 2 Geotextile used as a filter
below the ACB shall be a [woven] [non-woven] fabric, and shall meet the
requirements specified in Table 2. The property values (except for AOS)
represent minimum average roll values (MARV) in the weakest principal
direction.
SPECIFIC=GEOTEXTILE> SPECIFIC=GEOTEXTILE>
SPECIFIC=GEOTEXTILE>
S
SPECIFIC=GEOTEXTILE> 2
ECTION 02382
Page 13
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