SECTION 02320 BACKFILL

SECTION 02320 BACKFILL

PART 1 GENERAL
1.1 SUMMARY
A. Section Includes:
1. Fill material
2. Geotextile fabric for ground stabilization
3. Geotextile filter fabric for use with rip rap

1.2 REFERENCES
A. State of Illinois, Department of Transportation Standard Specifications for Road and
Bridge Construction, latest edition, and Illinois Department of Transportation
Supplemental Specifications and Recurring Special Provisions, latest edition, and
hereinafter referred to as the Standard Specifications.
B. American Association of State Highway and Transportation Officials:
1. AASHTO T180 - Standard Specification for Moisture-Density Relations of Soils
Using a 4.54-kg (10-lb) Rammer and a 457-mm (18-in.) Drop.
C. American Society for Testing and Materials:
1. ASTM D698 - Standard Test Method for Laboratory Compaction Characteristics
of Soil Using Standard Effort (12,400 ft-lbf/ft3 (600 kN-m/m3)).
2. ASTM D1556 - Standard Test Method for Density of Soil in Place by the SandCone
Method.
3. ASTM D1557 - Standard Test Method for Laboratory Compaction
Characteristics of Soil Using Modified Effort (6,000 ft-lbf/ft3 (2,700 kN-m/m3)).
4. ASTM D2167 - Standard Test Method for Density and Unit Weight of Soil in
Place by the Rubber Balloon Method.
5. ASTM D2922 - Standard Test Method for Density of Soil and Soil-Aggregate in
Place by Nuclear Methods (Shallow Depth).
6. ASTM D3017 - Standard Test Method for Water Content of Soil and Rock in
Place by Nuclear Methods (Shallow Depth).
7. ASTM D4253 - Standard Test Methods for Maximum Index Density and Unit
Weight of Soils Using a Vibratory Table.
1.3 SUBMITTALS
A. Section 01330 - Submittal Procedures: Requirements for submittals.
B. Product Data: Submit data for geotextile fabric indicating fabric and construction.
C. Samples: Submit, in air-tight containers, 30 lb sample of each type of fill to testing
laboratory.
D. Materials Source: Submit name of imported fill materials suppliers.
E. Manufacturer's Certificate: Certify Products meet or exceed specified requirements.

PART 2 PRODUCTS

2.1 FILL MATERIAL
A. Crushed Stone:
1. Crushed Stone: Imported stone processed by mechanical crushing of rock with
substantially all faces fractured by the crushing; free of shale, clay, friable
material, sand, debris; graded in accordance with CA7, Section 1004 of the
Standard Specifications.

Gradation Requirements for Crushed Stone:
Sieve Size Percent Passing
1-1/2 inch 100%
1 inch 90 to 100
1/2 inch 30 to 60
No. 4 0 to 10

B. Bedding/Cover Material:
1. Crushed Stone Chips: Crushed stone chips shall be made from crushing sound
limestone, dolomite ledge rock, or other rock materials of regional significance.
The material shall be hard, tough and durable.  The crushing process shall
produce material of which 85% to 100% of the particle shall have at least one
machine fractured face, crushed pea gravel will be acceptable if it meets this
criteria; graded in accordance with CA16, Section 1004 of the Standard
Specifications:

   Gradation Requirements for Crushed Stone Chips:
Sieve Size Percent Passing
1/2 inch 100%
3/8 inch 94 to 100
No. 4 15 to 45
No. 16 0 to 4

2. Bedding Sand:  Bedding sand shall consist of durable particles ranging in size
from fine to coarse in a substantially uniform combination.  The presence of
approximately 6% of fine clay or loam particles is desirable, but clay or loam
J:\5291\WORDPROC\SPECS\Bid Set\Div 02\02320.docx 02320-3 January 6, 2015
lumps are not permitted. The maximum moisture content shall be 10%; graded in
accordance with FA1, Section 1003 of the Standard Specifications

   Gradation Requirements for Bedding Sand:
Sieve Size Percent Passing
3/8 inch 100%
No. 4 94 to 100
No. 16 45 to 85
No. 50 3 to 29
No. 100 0 to 10

C. Sand or Gravel: Well grade sand or gravel; free of clay and silt lumps, loam, friable of
soluble materials, or organic matter meeting the following: graded in accordance with
CA6, Section 1004 of the Standard Specifications.
1. Gravel:

Sieve Size Percent Passing
1-1/2 inch 100%
1 inch 90 to 100
1/2 inch 60 to 90
No. 4 30 to 56
No. 16 10 to 40
No. 200 4 to 12

2. Sand: graded in accordance with FA1, Section 1003 of the Standard
Specifications
 
Sieve Size Percent Passing
3/8 inch 100%
No. 4 94 to 100
No. 16 45 to 85
No. 50 3 to 29
No. 100 0 to 10

J:\5291\WORDPROC\SPECS\Bid Set\Div 02\02320.docx 02320-4 January 6, 2015
D. Granular Backfill:  Fine to coarse-graded sand; free of clay and silt lumps, loam, friable
or soluble materials, or organic matter; graded in accordance with ASTM C136, within
the following limits:

Sieve Size Percent Passing
1 inch 100
No. 16 45 to 80
No. 200 2 to 10
E. Structural Fill (Engineered Fill):  Compacted fill shall be processed soil or rock materials
free of deleterious, friable, soluble, organic, or frozen matter, shall contain no chemicals
that may result in the material being classified as “contaminated”, and shall be lowexpansive
with a maximum Liquid Limit (ASTM D-423) of 30 and a Plasticity Index
(ASTM D-424) of 15.  All fill materials must be tested and approved by the Engineer
prior to placement (or delivery to the site if imported). On-site soils are not considered
suitable as structural fill.
F. Rip Rap:  Stone shall be according to Standard Specifications 281 and 1005, gradation
RR4.  
G. Heavy Rip Rap:   Stone shall be according to Standard Specifications 281 and 1005,
gradation RR5.Common Fill:  Soil, free of non-earth materials, less than 7% organic
content defined by Loss-on-Ignition.  Test ASTM D-2974, and maximum particle size of
8-inches.
H. Base Course:  As specified in Section 02721.
I. Drainage Stone:  Graded in accordance with ASTM C33 coarse aggregate, Size No. 57
within the following limits:

Sieve Size Percent Passing
1 inch 100
3/4 inch Maximum 10

J. Breaker Run Stone:  Large-sized aggregate resulting from the mechanical crushing of
rock, boulders, large stone or salvaged concrete, the results of which are not screened or
processed beyond the initial crushing size.  Breaker run stone shall be graded within the
following limits:

J:\5291\WORDPROC\SPECS\Bid Set\Div 02\02320.docx 02320-5 January 6, 2015
Sieve Size Percent Passing
5 inch 100
1½ inch 0 to 50

K. Fill materials shall be stored and handled by methods that prevent segregation of particle
sizes or contamination by mixing with other materials.
L. Controlled Low-Strength Material: Shall be in accordance with Section 593 and Section
1019 of the Standard Specifications.

2.2 GEOTEXTILE FABRIC FOR GROUND STABILIZATION
A. Non-woven, manufactured with the following minimum average roll values from samples
in accordance with ASTM D4354. The fabric shall be according to Section 1080.02 of
the Standard Specifications.  (The following values may be obtained from the
manufacturer.)

Property Value ASTM Test Method
Weight (oz/sq yd) 8.0 D3776
Grab Strength 200 lbs. D4632
Grab Elongation @
Break (%) 12 min D4632
Burst Strength 250 lbs. D3786
Trapezoidal Tear 75 lbs D4533
  (a)Alternatively, overlap geotextile a minimum of 18 inches.
B. Protect geotextile during storage from becoming wet, coming in contact with soil,
cement, or other foreign materials, and from exposure to sunlight.

2.3 GEOTEXTILE FILTER FABRIC FOR USE WITH RIP RAP
A. Non-woven, manufactured with the following minimum average roll values from samples
in accordance with ASTM D4354. The fabric shall be according to Sections 282 and
1080.03 of the Standard Specifications.  (The following values may be obtained from the
manufacturer.)
Property
Value
Gradation  Gradation
4 & 5     6 & 7
ASTM
Test Method
Weight (oz/sq yd) 6.0     8.0 D3776 (Mod.)
Burst Strength (psi) 250    300 D3786
Trapezoidal Tear Strength
(lb) 60    75 D5733
Grab Tensil Strength (lb) 160    200 D4632
Grab Tensil Elongation (%) 20     20 D4632
B. Protect geotextile during storage from becoming wet, coming in contact with soil,
cement, or other foreign materials, and from exposure to sunlight.

PART 3 EXECUTION
3.1 EXAMINATION
A. Section 01300 - Administrative Requirements: Coordination and project conditions.
B. Verify subdrainage, dampproofing, or waterproofing installation has been inspected.
C. Verify underground tanks are anchored to their own foundations to avoid flotation after
backfilling.
D. Verify structural ability of unsupported walls to support loads imposed by fill.

3.2 PREPARATION
A. Subgrade shall be prepared according to Section 301 of the Standard Specifications.
B. Proof roll to identify soft spots. Cut out soft areas of subgrade not capable of compaction
in place. Backfill with structural fill and compact to density equal to or greater than
requirements for subsequent fill material.
C. Scarify subgrade surface to depth recommended by engineer.
3.3 BACKFILLING
A. Backfill areas to contours and elevations with unfrozen materials.
B. Systematically backfill to allow maximum time for natural settlement. Do not backfill
over porous, wet, frozen or spongy subgrade surfaces.
C. Place geotextile fabric where required prior to placing next lift of fill.
D. Place and compact fill material in continuous layers not exceeding 8 inches compacted
depth and compact in accordance with schedule at end of this Section.
E. Employ placement method that does not disturb or damage other work.
F. Maintain optimum moisture content of backfill materials to attain required compaction
density.
J:\5291\WORDPROC\SPECS\Bid Set\Div 02\02320.docx 02320-7 January 6, 2015
G. Backfill against supported foundation walls. Do not backfill against unsupported
foundation walls.
H. Backfill simultaneously on each side of unsupported foundation walls until supports are
in place.
I. Backfill only against concrete that has been properly cured, coated, tested and accepted.
J. Fill excavations below bottom of foundation or footing elevations within influence zone
with concrete or structural fill.
K. Begin compaction of each layer at structure wall.
L. Utilize compactors of 550 lbs or less in weight within 5 feet of structure wall.
3.4 TOLERANCES
A. Top Surface of Backfilling Within Building Areas: Plus or minus 1 inch from required
elevations.
B. Top Surface of Backfilling Under Paved Areas: Plus or minus 1 inch from required
elevations.
C. Top Surface of General Backfilling: Plus or minus 3 inches from required elevations.

3.5 FIELD QUALITY CONTROL
A. Section 01400 - Quality Requirements: Testing and inspection services.
B. Testing: In accordance with ASTM D1557, ASTM D2922, ASTM D3017.
C. When tests indicate Work does not meet specified requirements, remove Work, replace
and retest at no cost to Owner.
D. Proof roll compacted surfaces under paving.

3.6 SCHEDULE
A. Mat Foundation and Interior Slab-On-Grade:
1. Existing soils or structural fill to 6 inches below subgrade soils or structural fill to
6 inches below subgrade elevation compacted to 95 percent and sand or gravel
fill to subgrade compacted to 95 percent unless noted otherwise on Drawings.
B. Exterior Side of Foundation Walls and Retaining Walls:
1. Granular Backfill, within 4 – 6 feet from walls, to 1–2 feet below subgrade
elevation, each lift compacted to 90 percent; compacted clayey soils to subgrade.
C. Fill Under Grass Areas:
1. Common fill, to 6 inches below finish grade, compacted to 85 percent.
D. Fill Under Landscaped areas and fill for Berm:
1. Common fill, to 12 inches below finish grade, compacted to 85 percent.
E. Fill Under Asphalt and Concrete Paving:
1. Crushed stone fill, to 12 inches below base course subgrade finish paving
elevation, compacted to 95 percent, and crushed stone fill to subgrade elevation
compacted to 100 percent.
F. Fill to Correct Over-excavation:
1. Gravel fill, flush to required elevation, compacted to 95 percent.
G. Fill to Prevent Erosion:
1. 12-inch minimum rip rap placed over non-woven geotextile filter fabric.

3.7 SECURITY
A. Provide security and facilities to protect Work, and existing facilities, and Owner's
operations from unauthorized entry, vandalism, or theft.
END OF SECTION