7-149 SECTION 760 – SLOPE STABILIZATION MATERIALS
760.01 SLOPE STABILIZATION NAILS . Solid bars, bearing plates, and nuts shall be galvanized in
accordance with ASTM A767 .
a.Bars. Bars shall be of the grade, size, and length specified in the Contract.
1.Solid . Solid bars shall be all thread bars in accordance with ASTM A615 .
2.Hollow . Hollow bars shall be all thread bars in accordance with ASTM A29 .
b.Bearing Plates . Bearing plates shall be steel plates in accordance with ASTM A36 . Bearing plates shall be of the size and design in the Contract.
c.Nuts . Nuts shall be in hexagonal steel nuts in accordance with ASTM A563 , Grade B.
760.02 SHOTCRETE . Shotcrete shall be a concrete mix with a maximum chloride ion content of 0.10%,
in each component, as determined in accordance with AASHTO T 260 . Shotcrete shall have an air content of 5.5% to 8.5% prior to application, as determined in accordance with AASHTO T 152 . Shotcrete shall have an absorption of less than 8% as determined in accordance with ASTM C642 . Shotcrete shall have a minimum 3 -day compressive strength of 2,000 psi and minimum 28 -day compressive strength of 4,000 psi as determined in accorda nce with AASHTO T 106 and shall be one of the following:
a.Dry Mix Shotcrete . Dry mix shotcrete shall be a prepackaged dry concrete mix where water is added to the mix at the nozzle.
1.Air Entrainment . Dry mix shotcrete shall have a minimum plastic air content of 2.5% as determined in accordance with AASHTO T 152 , using rodding as the consolidation method.
b.Wet Mix Shotcrete . Wet mix shotcrete shall be a bulk -produced concrete mix where all components are mixed, including water, before introduction t o the delivery hose. Wet mix shotcrete shall be batched in accordance with AASHTO M 157 or ASTM C94 . Wet mix shotcrete shall meet the following requirements:
1.Portland Cement . Portland c ement shall meet the requirements of Subsection 701.02 . The cement content shall be 600 pounds per cubic yard or greater. The water/cement ratio shall not exceed 0.45.
2.Aggregates . Aggregate shall meet the requirements of Subsection 704.15 .
3.Water . Water shall meet the requirements of Subsection 745 .01. 7-150 (4) Admixtures . Chemical admixtures shall meet the requirements of Subsection 725.02 for the respective type of chemical admixture used. Mineral admixtures shall meet the requirements of Subsection 725.03 for the respective type of mineral admixture used.
5.Air Entrainment . Wet mix shotcrete shall have a minimum plastic air content of 6% as determined in accordance with AASHTO T 152 , as sampled from the discharge of the mixing equipment. When shotcrete is required to be reinforced, reinforcement shall be in a ccordance with Subsection 713.0 5. Reinforced shotcrete shall have a minimum 7 -day flexural strength of 650 psi and a minimum 28 -day flexural strength of 900 psi. When coloring is specified in the Contract, colored admixture for integrally colored concrete conforming to ASTM C979 , ASTM C494 , and AASHTO M 194 shall be used. Colored admixture shall consist of a colored, water -reducing admixture containing no calcium chloride, with coloring agents that are lime - proof and ultraviolet light -resistant. Colored adm ixture shall be in powdered form.
760.03 Slope Drainage .
a.Strip Drain . Strip drains shall consist of a drainage core encapsulated in a geotextile. Strip drains shall have a minimum flow rate of 4.8 gallons per minute per foot of width as determined in accordance with ASTM D4716 with a 10 psi applied load, 1.0 gradient, and a 100 -hour seating period.
1.Drainage Core . The drainage core shall consist of long chain synthetic polymers composed of a minimum of 85%, by mass, polypropylenes, polyester, polyamine, polyvinyl chloride, polyolefin, or polystyrene. Drainage cores shall have a minimum compressive strength of 40 psi as determined in accordance with ASTM D1621, Procedure A .
b.Sheet Drain . Sheet drains shall be prefabricated drains consisting of geotextiles attached to one side of a drainage core. Sheet drains shall have a maximum flow rate of 21 gallons per minute per foot of width as determined in accordance with ASTM D4716 with a 25 psi applied load and a 1.0 gradient.
1.Drainage Core . Drainage cores shall consist of a 3 -dimensional polystyrene core formed with dimples.
2.Geotextile . Geotextile shall be a nonwoven geotextile.
c.PVC Drain . PVC drains shall be PVC pipes in accordance with ASTM D1785 . PVC drains shall be a minimum of 1.5 inches in diameter and a minimum of schedule 80. PVC pipe shall have two rows of uniformly spaced slots or three rows of uniformly spaced perforations. 7-151 760.04 WIRE MESH FACING . Wire mesh facing shall be a diamond pattern high -tensile steel wire mesh made from high strength wire of the diameter specified on the Plans with a minimum tensile strength of 256,000 psi. Wire mesh facing shall be provided with corrosion protection as specified by the manufact urer. Fasteners, spike plates, boundary ropes, and component materials such as wire rope clips, clamps, or any other connectors needed for the design shall be hot dipped galvanized for corrosion protection in accordance with ASTM A767 and meeting the syste m manufacturer’s specifications.
760.05 PRECAST CONCRETE RETAINING WALL SYSTEMS . Precast concrete retaining wall
systems shall include gravity, semi -gravity, and prefabricated modular walls. Precast concrete retaining wall systems shall be one of the sys tems on the Agency’s Approved Products List as approved by the Geotechnical Engineering Manager.
760.06 MECHANICALLY STABILIZED EARTH (MSE) WALL SYSTEMS . Mechanically stabilized
earth retaining wall systems shall be systems using soil reinforcements mecha nically connected to concrete facing panels. MSE wall systems shall be one of the systems on the Agency’s Approved Products List as approved by the Geotechnical Engineering Manager and shall meet the following requirements:
a.Reinforcing Mesh Elements . Reinforcing mesh elements shall be shop fabricated from cold drawn steel rod conforming to the requirements of ASTM A1064 , Grade 65 minimum, and shall be welded at the junctions between longitudinal and transverse wires in accordance with AASHTO M 336 . Galvanizing shall be applied after mesh fabrication and shall conform to the minimum requirements of AASHTO M 111 . The galvanizing thickness shall be determined and specified based on the design life requirements of the structure.
b.Loop Embeds . Loop e mbeds shall be fabricated from cold drawn steel rod conforming to ASTM A1064 . Loop embeds shall be welded in accordance with AASHTO M 336 and galvanized in accordance with AASHTO M 111.
c.Reinforcing Strips . Reinforcing strips shall be hot rolled from ba rs to the required shape and dimensions. At a minimum, their physical and mechanical properties shall conform to ASTM A572 , Grade 65. Galvanizing shall conform to the minimum requirements of AASHTO M 111 with a minimum application rate of 0.125 pounds per square foot. The actual galvanizing thickness shall be determined and specified based on the design life requirements of the structure.
d.Tie Strips . Tie strips shall be shop fabricated from hot rolled steel conforming to the minimum requirements of ASTM A570 , Grade 50 ( ASTM A1101 , Grade 50 minimum) or equivalent. Galvanizing shall conform to AASHTO M 111 . The minimum galvanizing application rate shal l be 0.125 pounds per square foot.
e.Fasteners . Fasteners shall consist of galvanized hexagonal cap screw bolts and nuts conforming to the requirements of ASTM F3125 , ASTM A449 , or equivalent. Fasteners shall be galvanized in accordance with AASHTO M 232 with a minimum application rate of 0.125 pounds per square foot and achieve 3.4 mils of galvanization on all surfaces of the fasteners. 7-152 (f) Bearing Pads . Bearing pads shall be preformed ethylene propylene diene monomer rubber pads conforming to ASTM D2000 , Grade 2, Type A, Class A with a durometer hardness of 60 (± 5).
760.07 GEOMEMBRANE LINER . Geomembrane liner shall be an impervious liner consisting of virgin
PVC resins, plasticizer, and stabilizers that prevents or minimizes the infiltration of water a nd deicing salts into the substrate below the liner. Geomembrane liners shall have a minimum thickness of 0.03 inches and shall meet the requirements of Table 760.07A . Individual widths of geomembrane liners shall be fabricated into larger sections by diel ectric seaming into a single piece, or into a minimum number of panels, as required to fit the application, unless otherwise specified in the Contract. Lap joints with a minimum joint width of 0.75 inches shall be used. TABLE 760.07A – PHYSICAL REQUIREMENT S FOR GEOMEMBRANE Property Test Method Requirement Thickness ASTM D1593 0.03 in. ± 5% Specific gravity ASTM D792 1.23 min. Tensile strength (breaking factor) ASTM D882 2,300 psi min. (835.3 lbs/ft width min.) Elongation at break ASTM D882 350% min. Modulus at 100% elongation ASTM D882 1,000 psi min. (363.2 lbs/ft width min.) Tear resistance ASTM D1004 3630.28 lbs/ft min. (9.07 lbs min.) Low temperature brittle failure point ASTM D1790 -28C max. Dimensional stability (100°C, 15 min.) ASTM D1204 3.5% change max. Water extraction loss change ASTM D3083 0.35% max. Volatility loss ASTM D1203 0.70% max. Resistance to soil burial loss ASTM D3083 -5% max. Tensile strength change, elongation at break, modulus at 100% elongation ASTM D3083 20% max. Hydrostatic resistance ASTM D751 85 psi min. Bonded seam strength (factory seam, breaking factor) 1 ASTM D3082 (Modified) 668 lbs/ft width Puncture resistance ASTM D4833 32 lbs min. 1 Factory bonded seam strength is the responsibility of the fabricator. 7-153 SECTIO N 780 – REPAI R MATERIALS 780.0 1 CONCRET E REPAI R MATERIALS . Concrete repair material shall be a prepackaged material and shall be one of the products listed on the Agency’s Approved Products List .
a.Concrete Repair Material, Type I . Type I concrete repair material shall be evaluated in accordance with the AASHTO Product Evaluation & Audit Solutions work plan for Evaluation of Rapid Set Concrete Patching Materials for Portland Cement Concrete , be a neat (having less than 5% aggregate retained on the 3/8 inch (9.50 mm ) sieve) overhead and vertical repair material, and meet the following requirements:
1.Compressive Strength . The neat material shall have a minimum 7 -day compressive strength of 2,000 psi and a minimum 28 -day compressive strength of 4,000 psi as determin ed in accordance with AASHTO T 106 .
2.Bond Strength by Direct Tension . The material shall have a minimum bond strength of 150 psi as determined in accordance with ASTM C1583 at 28 days, or sooner.
3.Freeze -Thaw Durability . The material shall have a min imum durability factor of 80, after 300 cycles, as determined in accordance with AASHTO T 161, Procedure A .
4.Length Change . The material shall meet the performance requirements of ASTM C928 as determined in accordance with AASHTO T 160 .
5.Chloride Ion Penetration . The material shall exhibit a chloride ion penetrability of Low, or less, as determined in accordance with AASHTO T 277 or AASHTO T 358 at 28 days, or sooner .
b.Concrete Repair Material, Type II . Type II concrete repair material shall be evaluated in accordance with the AASHTO Product Evaluation & Audit Solutions work plan for Evaluation of Rapid Set Concrete Patching Materials for Portland Cement Concrete , be a horizontal rapid setting repair material, and meet the requirements of Subsection 780.01(a) except as modified below .
1.Compressive Strength . The neat material shall have a minimum 3 -hour compressive strength of 1,200 psi and a minimum 7 -day compres sive strength of 5,000 psi as determined in accordance with AASHTO T 106 .
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 1301–1304 of 1,380.