569RECOMMENDED VALUES FOR RF id

id Geosynthetic Min RF id Max RF id HDPE uniaxial geogrid 1.20 1.45 PP biaxial geogrid 1.20 1.45 PVC -coated PET geogrid 1.30 1.85 Acrylic -coated PET geogrid 1.30 2.05 Woven geotextiles (PP and PET) 1.40 2.20 Nonwoven geotextiles (PP and PET) 1.40 2.50 Silt-film woven PP geotextiles 1.60 3.00

RFdu, Partial Factor for Durability / Aging is the combined partial factor for potential chemical and biological degradation. RF du shall be determined from polymer specific (HDPE and PP as identified by specific gravity and melt flow index and PETP as identifie d by CEG number and intrinsic viscosity) durability testing covering the range of expected soil environments. Prior to approval by the Engineer, the manufacturer shall submit test results from a minimum of at least four (4) tests conducted in accordance w ith EPA 9090 at temperatures of 73° and 122°F. EPA 9090 test results shall include the following minimum number of leachate types:

pH Minimum # of test results 3pH7 1 7<pH9 1 9<pH<11 1 11pH14 1

As a minimum, the following tests should be performed for geogrids after immersion in the above -described leachates:

TEST TEST PROCEDURE MAX % CHANGE ALLOWED Mass per Unit Area EPA 9090 ±1.0 Dimensions EPA 9090 ±1.0 Thickness ASTM D374C ±5.0 Wide Width Strip Tensile ASTM D4595 -2.0

characteristics of the interior reinforcement polymer. Therefore, any protective coating shall be removed prior to durability testing unless a minimum 40 micron coating thickn ess is used on flexible geogrids and certified by the manufacturer.

stabilized soil, cement stabilized soil or concrete), only polymers listed as “no effect” shall be use d within or adjacent to (3 feet shortest measurable distance) these soil environments (Ref: Table 28, FHWA/RD -89-186).

570 SOIL ENVIRONMENT PETP PE PP PVC Acid Sulfate Soils ? NE ? ? Organic Soils NE NE NE X Salt Affected Soils ? NE NE NE Ferruginous NE NE X X Calcareous X NE NE ? Modified Soils X NE NE ?

NE = No Effect ? = Questionable Use X = Not Recommended

RFdu shall not be less than the recommended minimum values discussed in FHWA/RD - 89-186 and listed below:

MINIMUM VALUES FOR RF du Products Aging Reduction factor, RF du – 100 years pH  3 3  pH  5 5  pH  8 8  pH  9 pH  9 PET Uncoated Mn  20,000 40CEG50 * 2.0 1.6 2.0 * PET Coated Mn  25,000 CEG30 * 1.3 1.15 1.3 * HDPE 1.1 1.1 1.1 1.1 1.1 Polypropylene 1.25 1.25 1.25 1.25 1.25 Geotextiles Mn  20,000 40CEG50 * 2.0 1.6 2.0 *

* Use of materials in this pH range is not recommended but can be used if product specific testing is done Mn = Number of Molecular Weight CEG = Carboxyl End Group

645.2.2 -Backfill Material: All backfill material used in the structure volume shall be reasonably free from organic or otherwise deleterious materials and shall conform to the following gradation limits as determined by AASHTO T -27:

Sieve Size Percent Passing 100 mm (4 in ch) 100 No. 4 100-30 No. 20 0-60 No. 200 0-50 Plasticity Index (PI)  20 (AASHTO T -90)