1107 - AGGREGATES FOR BACKFILL 1100-21
1107.1 Description
This specification covers aggregate for backfill. Us e this when structures, pipe, mechanically stabilized earth (MSE) walls (panel or modular), underdrain, permeable or crushed stone backfill requirements are specified in the Contract Documents.
1107.2 Requirements
a. Structures or Pipe.
1.Composition. Provide singly or in combination sand, gravel, or crushed stone. Consider limestone, calcite-cemented sandstone, rhyolite, basalt, and granite as crushed stone.
2.Quality 1. Soundness2, minimum (KTMR-21) ............................................................... 0.85 Wear3, maximum (AASHTO T 96) ............................................................... 45% For Structures Backfill Only: Coarse Aggregate Angularity4, minimum (KT-31) ........................................ 75% Fine Aggregate Angularity4, minimum (KT-50) ............................................ 40% 1Crushed aggregates with less than 10% material retained on the No. 4 sieve (excluding mineral filler supplements) must be produced from a source complying with the official quality requirements of this Section prior to crushing. 2The above requirements for soundness do not apply for aggregates having less than 10% material retained on the No. 4 sieve. 3The above requirements for wear do not apply to aggregates having less than 10% material retained on the No. 8 sieve. 4Required testing for sand and gravel.
3.Product Control.
a.Gradation and Plasticity. TABLE 1107-1: AGGREGATES FOR STRUCTURES OR PIPE BACKFILL Type Percent Retained-Square Mesh Sieves Plasticity Index (Max.) 2” 1 ½” 1” ¾” 3/8” No. 4 No. 8 No. 40 No. 200 SB-1 0 0-10 15-40 50-75 95-100 SB-2 0 0-20 40-70 75-100 95-100 SB-3 0 0-5 5-30 35-60 45-70 60-84 80-92 8 PB-11 0 0-10 15-40 50-75 95-100 PB-21 0 0-20 40-70 75-100 95-100 PB-31 0 0-30 35-60 50-75 70-90 90-100 8 1Use of PB is required for PE and PVC pipe backfill.
b.Deleterious Substances. Shale or shalelike material, maximum (KT-8) ................................. 3.0% Clay Lumps and friable particles, maximum (KT-7) ....................... 3.0% Sticks (wet), maximum (KT-35) ...................................................... 1.0%
4.Foundation Stabilization. Use SB aggregates at those locations where the use of SB aggregates for foundation stabilization is specified elsewhere in the Contract Documents. When the preceding sentence applies, use SB-3 when the expected depth of foundation stabilization is less than 6 inches. Except at the locations described above, the use of altern ate granular materials (except chat) may be permitted, but only with the approval of the District Materials Engineer. 1107 - AGGREGATES FOR BACKFILL 1100-22 b. MSE Walls : Precast Panel and Modular Block with Steel Soil Reinforcing Mesh or Steel Reinforcing Strips and Tie Strips.
1.Composition. Use granular backfill material in th e structure volume of sand, sand-gravel, or crushed stone, reasonably free from organics or other deleterious materials, and complies with the following:
2.Quality. Submit representative material samples fo r the following tests to the Materials and Research Center, 2300 Van Buren, Topeka, KS 66611 (ATTENTIO N: Geotechnical Enginee r) for acceptance prior to utilizing this material on the project.
a.The Plasticity Index (P.I.) is 6 maximum, determined by KT-10.
b.An angle of internal friction of 34 degrees or greater, as determined by the standard direct shear test – AASHTO T 236, utilizing a sample of the material compacted to 95 percent of AASHTO T 99 Methods C or D (with oversize corr ection, as outlined in Note 9 in AASHTO T 99) at optimum moisture content.
c.Soundness. Use material substantially free of shale or other soft, poor durability particles as determined in accordance with SECTION 1115 . “Freeze and Thaw”, minimum 0.90 as determined in DIVISION 1100.
d.Wear. Los Angeles Wear Abrasion, maximum 40%.
e.Provide material that complies with TABLE 1107-2. TABLE 1107-2: ELECTROCHEMICAL REQUIREMENTS (PANEL) Requirements Test Method Resistivity > 5000 ohm-cm AASHTO T 288 pH: 5.0 to 10.0 AASHTO T 289 Organic Content < 1% AASHTO T 267 If the resistivity is less than 5000 ohm-cm, but greater than 3000 ohm-cm, the backfill material can be accepted if it complies with TABLE 1107-3. TABLE 1107-3: ADDITIONAL ELECTROCHEMICAL REQUIREMENTS Property Requirements Test Method Chlorides < 100 parts per million ASTM D 4327 Sulfates < 200 parts per million ASTM D 4327
3.Product Control.
a.Gradation. TABLE 1107-4: AGGREGATES FOR PANEL MSE WALLS BACKFILL Percent Retained – Square Mesh Sieves 4” No. 40 No. 200 0 40 - 100 95 - 100
b.Coefficient of Uniformity. Provide material with a minimum coefficient of uniformity of 4.0 as defined by ASTM D 2487 for systems that utilize steel reinforcing strips and tie strips (Reinforced Earth). Material with a coefficient of unifo rmity less than 4.0 may be accepted based on the results of pullout tests conducted by the University of Kansas, Civil Engineering Department, Geotechnical Section. (Contact: Dr. Jie Han @ 785-864-3714 or Dr. Bob Parsons @ 785-864- 2946.)
4.Use only crushed stone in District 1. For select granular backfill material composed of crushed stone, submit a proposed project gradation with single-point gradations and tolerances for approval. For sand and sand-gravel combinations, a project gradation will be issued that will specify gradation tolerances after the proposed material is approved. Any quality assurance samples which fall outside the tolerances will nece ssitate re-approval to be in compliance with subsection 1108.2 b.(2). 1107 - AGGREGATES FOR BACKFILL 1100-23 c. MSE Walls: Modular Block with Soil Reinforcing Geogrid.
1.Composition. Use granular backfill material in th e structure volume of sand, sand-gravel, or crushed stone, reasonably free from organics or otherwise deleterious materials, and complies with the following:
2.Quality. Submit representative material samples fo r the following tests to the Materials and Research Center, 2300 Van Buren, Topeka, KS 66611 (ATTENTIO N: Geotechnical Enginee r) for acceptance prior to utilizing this material on the project.
a.The Plasticity Index (P.I.) is 6 maximum, determined by KT-10.
b.An angle of internal friction of 34 degrees or greater, as determined by the standard direct shear test – AASHTO T 236, utilizing a sample of the material compacted to 95% of AASHTO T 99 Methods C or D (with oversize correction, as outlined in Note 9 in AASHTO T 99) at optimum moisture content.
c.Soundness. “Freeze and Thaw”, minimum 0.90 as determined in DIVISION 1100.
d.Wear. Los Angeles Wear Abrasion, maximum 40%.
e.Provide material that complies with TABLE 1107-5. TABLE 1107-5: ELECTROCHEMICAL REQUIREMENTS (Block) Requirements Test Method (Mesa) pH > 3.0 AASHTO T 289 (Anchor Landmark) pH: 3.0 to 9.0 AASHTO T 289 Organic Content < 1% AASHTO T 267
3.Product Control.
a.Gradation. TABLE 1107-6: AGGREGATES FOR MODULAR BLOCK MSE WALLS BACKFILL Type of Material % Retained – Square Mesh Sieves 1” No. 40 No. 200 Sand 0 40-100 95-100 Crushed Stone 0 40-100 95-100 Limit the maximum particle size to ¾ inch for geosyn thetic reinforced structures and for epoxy or PVC coated reinforcements. Use only crushed stone in District 1. For select granular backfill material composed of crushed stone, submit a proposed project gradation with single-point gradations and tolerances for approval. For sand and sand-gravel combinations, a project gradation will be issued that will specify gradation tolerances after the proposed material is approved. Any quality assurance samples which fall outside the tolerances will nece ssitate re-approval to be in compliance with subsection 1108.2 c.(2). d. Underdrain, Permeable or Granular Backfill.
1.Composition. Provide washed aggregate Type BD-1 and Type UD-1 composed of crushed or uncrushed gravel, or crushed stone.
2.Quality. Soundness, minimum (KTMR-21) ................................................................. 0.90 Wear, maximum (KTMR-24) ........................................................................ 40%
3.Product Control. Provide aggregate that complies with TABLE 1107-7 TABLE-1107-7: AGGREGATES FOR UNDERDRAIN AND OTHER PERMEABLE BACKFILL Type Percent Retained-Square Mesh Sieves 1 ½” 1” ¾” 3/8” No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 BD-1* 0 0-10 10-40 80-100 90-100 93-100 98-100 UD-1 0 0-15 40-60 70-95 98-100 *BD-1 is intended for use with a filter fabric. 1107 - AGGREGATES FOR BACKFILL 1100-24
4.Deleterious substances. Shale or shalelike material, maximum (KT-8) ............................................... 3.0% Clay Lumps and friable particles, maximum (KT-7) ..................................... 3.0% Sticks (wet), maximum (KT-35) .................................................................... 1.0% e. Crushed Stone.
1.Composition. Provide material produced by the crushing of any type of stone complying with the following.
2.Quality. Soundness, minimum (KTMR-21) ................................................................. 0.70 Wear, maximum (AASHTO T 96) ................................................................. 50%
3.Product Control.
a.Size Requirements. Provide uniformly graded cr ushed stone, from coarse to fine, for backfill that complies with TABLE 1107-8: TABLE 1107-8: CRUSHED STONE BACKFILL Percent Retained-Square Mesh Sieves 2” 3/8” No. 16 0 20 - 50 50 - 100
b.Deleterious Substances. Clay lumps and friable particles, maximum (KT-7) ........................ 5.0%
1107.3 Test Methods
Test aggregates according to the applicable provisions of SECTION 1115.
1107.4 Prequalification
Prequalify aggregate sources according to subsection 1101.4.
1107.5 Basis of Acceptance
Aggregates covered by this subsection are accepted based on the procedures described in subsection 1101.5.
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Source: Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 678–681 of 978. View official source ↗