for Highway Construction Page 705 of 71 5 SECTION 718 – GEOTEXTILES
718.01 General Requirements.
Use geotextile consisting of a long chain polymeric filaments or yarns oriented into a stable n etwork that retains its relative structure, including selvedges, during handling, placement , and design service life. Ensure that at least 85 percent by weight of the long chain polymers are polyolefins, polyesters, or polyamides. Ensure the geotextile has no defects or tears. The Engineer may reject geotextile if dimensional stability or resistance to ambient temperatures, acid or alkaline conditions, and micro- organisms/insects are unsatisfactory. Provide geotextile in accordance with the properties indicated for each specified use. Provide the geotextile without treatment or coating that might adversely alter its physical properties after installation.
718.02 Certi fication.
Submit the geotextile manufacturer’s certification consisting of certified test results showing the geotextile and factory seams meet the specifications. Ensure the certification includes the named product and representative samples have been delivered and tested as specified. Include the following information in the certif ication for each geotextile to be used:
1.Manufacturer’s name and current address.
2.Full product name.
3.Geotextile roll number.
4.Proposed geotextile use(s).
5.Certified test results. Submit the name and address of the testing agency and the test date on the identification certification. Provide a means to identify the geotextile , including a lot number that can be used to ensure the product delivered is the certified product. Submit a certified copy of the test results including each test result, each mean roll value, the calculated standard deviation for each lot, and the manufacturer’s coefficient of variation for test results. Submit duplicat e certification with 1 copy sent with the shipment to the Engineer and 1 copy sent to the Central Materials Laboratory .
718.03 Samples.
The Engineer will sample geotextiles for QA testing . Cut the geotextile samples from the roll with scissors, sharp knife, or by another suitable method that produces a smooth edge and does not cause ripping or tearing. Do not take samples from the outer wrap of the geotextile rol l or from the inner wrap of the core. The minimum dimension for each sample is 6 feet by the full roll width. Submit 1 sample for each lot. Label the samples with the lot and batch number, date of sampling, project number, spec ifications, manufacturer, and product name. The Department defines a lot as geotextile rolls within the same consignment or shipment that a manufacturer produced with the same lot number, and product name or designation. for Highway Construction Page 706 of 71 5 Before installing geotextiles, submit samples of sewn seams to the Central Materials Laboratory . Sew the seam sampling using the same equipment and procedures as will be used to sew the production seams. If production seams are sewn in both the machine and cross -machine directions, provide sewn seams for sampling oriented in both the machine and cross -machine directions and at least 6 feet long in each direction. If the seams are sewn in the factory, the Engineer will obtain samples of the factory seam at random from the rolls to be used.
718.04 Testing.
The Department may perform tests as necessary to determine the geotextile properties are in accordance with the values specified for the intended application. Geotextile property requirements specified are minimum average roll values. Determine the tensile strengths in both machine and cross -machine directions.
718.05 Drainage Geotextile P roperty Requirements.
Provide nonwoven or monofilament woven geotextiles. The Engineer will not accept slit film or slit tape geotextiles for drainage applications. Meet the requirements in Table 718.05- 1 below. Table 718.05 -1 – Drainage Geotextile Criteria Geotextile Property Test Method Minimum Average Roll Values (in weaker principal direction) Grab Tensile Strength, lb ASTM D 4632 180 Puncture Strength, lb ASTM D 6241 450 Apparent Opening Size (AOS) , Standard Sieve ASTM D 4751 #70 or Finer Permittivity, sec-1 ASTM D 4491 0.7 Note: Strength properties of drainage geotextiles placed on level or near level surfaces (e.g., under drain blankets, on subgrade) must meet those specified in 718.07.
718.06 Riprap /Erosion Control Geotextile Property Requirements .
Provide nonwoven or monofilament woven geotextiles. The Engineer will not accept slit fil m or slit tape geotextiles for riprap/erosion control applications, including installation behind gabions. Meet the requirements in Table 718.06- 1. for Highway Construction Page 707 of 71 5 Table 718.06 -1 – Riprap/ Erosion Control Geotextile Criteria Geotextile Propert y Test Method Minimum Average Roll Values (a) (in weaker principal direction) Grab Tensile Strength, lb ASTM D 4632 315 / 200 Grab Elongation, % ASTM D 4632 <50% / ≥50% Puncture Strength, lb ASTM D 6241 600 / 450 Trapezoidal Tear, lb ASTM D 4533 110 / 80 Apparent Opening Size (AOS) , Standard Sieve ASTM D 4751 #40 or Finer Permittivity, sec-1 ASTM D 4491 0.7 Ultraviolet (UV) Radiation Stability ASTM D 4355 70% Strength Retained @ 150 hours
a.The dual values for strengths for each geotextile type are related to the grab elongation. For geotextiles with elongation less than 50%, the first strength values are applied. For geotextiles with elongation equal to or greater than 50%, the second strength values are applied. Higher strength is required for geotextiles with lower elongation.
718.07 Subgrade Separation Geotextile Prope rty Requirements .
Provide nonwoven or monofilament woven geotextiles, except only nonwoven geotextile can be used for Type III. The Engineer will not accept slit film or slit tape geotextiles for subgrade separation. Meet the requirements in Table 718.07- 1. Table 718.07 -1 – Subgrade Separation Geotex tile Criteria Minimum Average R oll Values(d) (in weaker principal direction) Geotextile Property Test Method Type I (a) Type II (b) Type III (b)(c) Grab Tensile Strength, lb (d) ASTM D 4632 180 / 110 270 / 180 270 / 180 Grab Elongation, % (d) ASTM D 4632 < 50% / ≥ 50% Puncture Strength, lb (d) ASTM D 6241 500 / 300 600 / 450 600 / 450 Trapezoidal Tear Strength, lb (d) ASTM D 4533 70 / 40 100 / 75 100 / 75 Apparent Opening Size (AOS) , S d d Si ASTM D 4751 #30 or Finer #40 or Finer #70 or finer Permit tivity, sec-1 ASTM D 4491 0.05 0.05 0.7 for Highway Construction Page 708 of 71 5 (a) Type I refers to moderate survivability conditions. Moderate survivability is low to moderate ground pressure equipment, 40 psi or less, with 12 to 18 inch initial lift thickness or high ground pressure equipment, greater than 40 psi, with more than 18 inch initial lift thickness.
b.Type II and Type III refers to high survivability conditions. High survivability is low to moderate ground pressure equipment with 6 to 12 inch initial lift thickness or high ground pressure equipment with 12 to 18 inch initial lift thickness.
c.Type III is used when subgrade separation geotexti le will also function in a drainage application.
d.The dual values for strengths for each geotextile type are related to the grab elongation. For geotextiles with elongation less than 50%, the first strength values are applied. For geotextiles with elongation equal to or greater than 50%, the second strength values are applied. Higher strength is required for geotextiles with lower elongation. The subgrade condition is assumed to be cleared of rocks, stumps and large limbs, and graded reasonably smooth. If subgrade preparation or clearing is not as stated, or cover material is angular shot rock, even higher survivability geotextiles may be necessary.
718.08 Pavement Overlay Geotextile Property Requirements .
Provide only nonwoven geotextiles. Meet the requirements in Table 718.08- 1. Table 718.08 -1 – Overlay Geotextile Criteria Geotextile Property Test Method Minimum Average Roll Values (in weaker principal direction) Grab Tensile Strength, lb ASTM D 4632 80 Grab Tensile Elongation, % ASTM D 4632 50 Trapezoidal Tear Strength, lb ASTM D 4533 40 Asphalt Retention, gal/yd2 ASTM D 6140 0.20
718.09 Temporary Silt -Fence Geotextile Property Requirements .
Meet the requirements in Table 718.09- 1. Table 718.09 -1 – Temporary Silt Fence Geotextile Criteria Geotextile Property Test Method Minimum Average Roll Values (in weaker principal direction) Grab Tensile Strength, lb ASTM D 4632 90 Grab Tensile Elongation, % (At 50% of minimum Tensile Strength, 45 lb) ASTM D 4632 50 max (a) Permittivity, sec-1 ASTM D4491 0.05 Apparent Opening Size (AOS) ASTM D4751 #20 or finer Ultraviolet (UV) Radiation Stability Retained ASTM D4355 70% Strength Retained @ 150 hours
a.For wire -supported silt fence g eotextile, elongation requirements are not applicable. for Highway Construction Page 709 of 715 SECTION 719-RESERVED
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 741–744 of 768.