604Soil and Drainage Geotextiles

604.1 Description

This Work consists of providing and installing geotextiles.

604.2 Materials – Reserved

604.2.1 Classifications

The Contractor shall use the class of geotextile in accordance with Table 604.2.1:1, “Cross Reference of Old Classes to New Classes of Geotextiles.” Table 604.2.1:1 Cross Reference of Old Classes to New Classes of Geotextiles Geotextile Old class New class Subsurface drainage A or B 2 or 3 Sediment control B 2 Erosion control C or D 1 or 2 Separation C or D 2 or3 Stabilization None 1 The Department specifies Class 1 for more severe or harsh insta llation conditions where there is a great potential for geotextile damage and specifies Class 2 and 3 for less severe conditions.

604.2.2 Subsurface Drainage Geotextiles

The Department prohibits the use of woven slit film geotextiles or geotextiles made from yarns of a flat, recording-like character. The Contractor shall provide Cl ass 2 geotextiles for drain syst em installations that require use of very coarse, sharp angular aggregate with a one (1) inch diameter or greater, or require a depth of trench greater than six (6) ft. The Contractor shall provide Cl ass 3 geotextiles for general un derdrain installations that require smooth graded surfaces hav ing no sharp angular projecti ons and fine aggregate.

604.2.3 Erosion Control Geotextiles

The Department prohibits the use of woven slit film geotextiles or geotextiles made from yarns of a flat recording-like character. If the Contractor us es a woven monofilament geotextile, the Contractor shall provide a Class 2 geotextile; otherwise the Contractor shall provide a Class 1 geotextile. 604.2.4 Separation Geotextiles The Contractor shall provide separation geotextiles that are of woven or non-woven Material. The Contractor shall use a Class 2 separator for Pavement Struc tures constructed over soils with an R-value greater than 20 to separate dissimilar Ma terials where water seepage is Section 604: Soil and Drainage Geotextiles Page 629 allowable. The Contractor shall use Class 2 geotextiles where installation requires a depth of trench greater than ten (10) ft, where stone drop height is to be more than zero (0), or where there is no sand cushion prot ection. The Department requires f ield trials where stone drop height exceeds three (3) ft or wher e individual stone weight ex ceeds 250 lb. The Contractor shall use Class 3 geotextiles to prevent mixing of a Subgrade soil and an aggregate cover Material (Subbase, base, select Embankment, etc .), to separate dissimilar Materials where water seepage is allowable. The Contractor sha ll not use Class 3 geotextiles under pavement. The Contractor may also use Class 3 geotextile s in Structures or under conditions where the geotextile is protected by a sand cushion or by “zero (0) drop height” placement of stone. The Contractor shall use Table 604.2.4:1, “Required Class of Se parator Geotextile and Cover Thickness for R-values Greater Than or Equal to 20,” to d etermine the class of separator geotextile and the required minimum thickness. Table 604.2.4:1 Required Class of Separator Geotextile and Cover Thickness for R-values Greater Than or Equal to 20 Required minimum cover thickness, compacted Required class of geotextile 6 inch. 2 12 inch. 3 The Contractor shall not use aggregate larger than one (1) inch .

604.2.5 Stabilization Geotextiles

The Contractor shall provide stabilization geotextile in wet, s aturated conditions to provide separation, filtration, and also reinforcement. The Co ntractor shall use stabilization geotextiles for Pavement Structure s constructed over soils with R-values from ten (10) to 20. The Contractor may provide stabilization geotextiles made of wo ven or non-woven Material. The Contractor may use stabilization geotextiles in applicatio ns that require a design by a licensed professional Engineer. The Contractor shall obtain De partment approval of these designs.

604.2.6 Certification

For each class of geotextile fabric, the Contractor shall provi de a certificate from the manufacturer stating that the geotextile meets the physical and chemical requirements in accordance with AASHTO M 288, and that geotextile fabric meets R-value requirements for the respective application. The Contractor shall include in the certification the product n ame, chemical composition of the filaments or yarns, or other relevant information to ful ly describe the geotextile. The Contractor shall submit the certification to the Project Ma nager before geotextile placement. R-values corresponding to Califor nia bearing ratio (CBR) used i n AASHTO M 288 are presented in Table 604.2.6:1, “CBR Values Used in AASHTO M 288 and Corresponding R- values.” CBR Values Used in AASHTO M 288 and Corresponding R-values Soil strength (CBR) Corresponding R-value 1 10 2 15 3 20

604.3 Construction Requirements

604.3.1 Geotextile Packaging, Storage, and Handling

The Contractor shall use geotextile rolls wrapped with a Materi al to protect the geotextile, including the ends of the roll, from damage. The Contractor shall cover and elevate geotextile rolls during storage to protect them from the following: 1. Site construction damage (tea ring, excessive mud, wet cement , or epoxy); 2. Precipitation; 3. Extended ultraviolet radiati on including direct sunlight; 4. Chemicals that are str ong acids or strong bases; 5. Flames including welding sparks; and 6. Temperatures above 160 °F and below -22 °F.

604.3.2 Geotextile Exposure After Placement

The Contractor shall not expose geotextiles to the elements aft er placement for more than 14 Days, unless otherwise directed by the Project Manager.

604.3.3 Site Preparation

The Contractor shall prepare the installation site by clearing and grading the area and preparing a firm, smooth surface on which to place the geotexti les. The Contractor shall remove sharp objects and large stones and cut trees and shrubs flush with the smooth surface. The Contractor shall ensure correct orientation (roll direction ). The Contractor shall place geotextiles as smoothly as possible on the prepared surface; pu ll tight, align, and anchor such that the geotextile is free of wrinkles and does not show evide nce of holes, tears, or rips before placing cover Material on the geotextile. Before placin g cover Material, the Contractor shall hold geotextiles in place by pins, staples, or piles of f ill or rock as required by fill placement procedures. On curves, the Contractor shall fold or cut geotextiles to conform to the curve. The Department will not allow vehicles directly on the geotexti le, but will allow vehicles after the Contractor places at least six (6) inches of cover Ma terial on the geotextile. The Contractor shall not allow vehicles to turn on the cover Materi al until at least two (2) lifts of cover Material have been placed.

604.3.4 Backfill

The Contractor shall obtain approval from the Project Manager b efore beginning backfill operations. The Contractor shall not end dump backfill directl y onto exposed geotextile. The Section 604: Soil and Drainage Geotextiles Page 631 Contractor shall backfill by end dumping onto previously spread backfill and then pushing the dumped backfill over the exposed geotextile. On Subgrades havi ng an R-value less than ten (10), the Contractor shall dump and spread the Material placed on the geotextile to minimize the potential of a localized Subgrade failure. The Contractor shall backfill in layers from six (6) inches to eight (8) inches deep (uncompacted) unless otherwise specified in the Contract. Afte r placement, the Contractor shall compact each lift to 95% of maximum density in accordance with AASHTO T 180 (Modified Proctor), Method D (TTCP Modified). The Contractor s hall compact the top lift in accordance with Section 207, “Subgrade Preparation.” The Contr actor may use vibratory compaction Equipment on initial layers of Material, if approved by the Project Manager. The Contractor shall repair ru ts occurring during construction by filling with additional Material and compacting to the s pecified density to maintain an even backfill surface and the minimum lift thickness over the geotextile. The Contractor shall obtain the Project Manager’s approval of g eotextile placement before covering.

604.3.5 Subsurface Drainage Geotextiles

The Contractor shall place geotextiles in accordance with Secti on 605, “Drains,” where specified. The Contractor shall use subsurface drainage geotextiles agains t soil in an underground drainage system or in an edgedrain to allow for long-term passa ge of water into a subsurface drain system while retaining the in-situ soil. The primary fun ction of the geotextile in subsurface drainage applications is filtration. The Contractor shall provide one (1) soil sample to the Departm ent for testing to confirm the applicable apparent opening size based on the percent of in -situ soil passing the No. 200 sieve and cohesiveness (PI). The Contractor shall compact the aggregate with vibratory Equip ment to a minimum compaction of 95% of maximum density in accordance with AASHTO T 180 (Modified Proctor), Method D (TTCP Modified). If a higher compactive eff ort is necessary, the Contractor shall substitute a geot extile suited for more severe installation conditions.

604.3.6 Sediment Control Geotextiles

The Contractor shall place geotextiles in accordance with Secti on 603, “Temporary Erosion and Sediment Control,” where necessary. The Contractor shall place and maintain sediment control geotex tiles as a temporary control measure to prevent eroded soil from being transported o ff the construction site to rivers, streams, and impoundments and to prevent damage to priv ate property from storm water runoff.

604.3.7 Erosion Control Geotextiles

The Contractor shall place geotextiles in accordance with Secti on 602, “Slope and Erosion Protection Structures,” where necessary. The Contractor shall use erosion control geotextiles between er osion control Structures (rip-rap and gabions) and the in-situ soil to prevent soil loss resulting in excessive scour and to Section 604: Soil and Drainage Geotextiles Page 632 mitigate hydraulic uplift pressures that may cause instability of an erosion control Structure.

604.3.8 Separation/Stabilization Geotextiles

The Contractor shall use separation/stabilization geotextiles a s a semi-permeable separator to prevent mixing of a Subgrade soil and sub-base or base Material. The Contractor shall fold, overlap, sew, or join adjacent geote xtile rolls in accordance with Table 604.3.8:1, “Minimum Overlap Requirements for Separat ion/Stabilization Geotextiles,” unless manufacturer's recommendations or the Cont ract are more stringent. Table 604.3.8:1 Minimum Overlap Requirements for Separation/Stabilization Geote xtiles Soil strength R-value Un-sewn seams overlap (inch) Sewn seams overlap (inch) <10 — 9 10–15 40 8 15–20 30 3 >20 24 — The Contractor shall ensure that both factory and field sewn or sealed seams meet or exceed the strength requirements as required by the manufacture r.

604.3.9 Repair of Damaged Geotextiles

To repair subsurface drainage, ero sion control, and sediment co ntrol geotextiles, the Contractor shall clear the damaged area and repair in accordanc e with the manufacturer's recommendations. The Contractor shall obtain the Project Manag er's approval of repairs. To repair separation/stabilization geotextiles, the Contractor shall clear the damaged area plus an additional three (3) ft around the damaged area and rep air in accordance with Table

604.3 8:1, “Minimum Overlap Requirements for Separation/Stabili zation Geotextiles,” unless

manufacturer's recommendations or the Contract are more stringe nt. The Contractor shall replace removed cover Material and compact to the specified den sity.

604.4 Method of Measurement

The Department will only measure the area of one (1) layer at g eotextile overlaps.

604.5 Basis of Payment

Pay Item Pay Unit Geotextile Class Square Yard Payment for achieving Subgrade preparation in accordance with Section 207, “Subgrade Preparation” will be paid as Subgrade Preparation.

604.5.1 Work Included in Payment

The following Work and items will be considered as included in the payment for the main item(s) and will not be measured or paid for separately: 1. Repair of damaged geotextile fabric as a result of the Contr actor's negligence, improper shipping, handling, packaging, or storing; Section 604: Soil and Drainage Geotextiles Page 633 2. Geotextile packaging, storage and handling; and 3. Overlaps, anchoring, splicing and seam assemblies. Section 605: Drains Page 634