Embankment, Borrow, and Backfill EMBANKMENT, BORROW, AND BACKFILL
Part 1 — General
1.1 Section Includes
A.Embankment, backfill, and bridge approach embankments.
1.2 Related Sections
A.Section 01572: Dust Control and Watering
B.Section 02721: Untreated Base Course (UTBC)
C.Section 03575: Flowable Fill
1.3 References
A.AASHTO M 145: Classification of Soils and Soil -Aggregate Mixtures for Highway Construction Purposes
B.AASHTO T 11: Materials Finer than 75 μm (No. 200) Sieve in Mineral Aggregates by Washing
C.AASHTO T 27: Sieve Analysis of Fine and Coarse Aggregates
D.AASHTO T 99: Moisture -Density Relations of Soils Using a 2.5 kg (5.5- lb) Rammer and a 305 mm (12 inch) Drop
E.AASHTO T 180: Moisture- Density Relations of Soils Using a 4.54 kg (10- lb) Rammer and a 457 mm (18 inch) Drop
F.UDOT Materials Manual of Instruction G UDOT Minimum Sampling and Testing Requirements
1.4 Definitions
A.Borrow material – imported material for use in a constructed fill or backfill.
B.Embankment material – suitable material from project roadway excavation or other excavation for use in a constructed fill or backfill. Embankment, Borrow, and Backfill
C.Well- graded material – Material having an even distribution of different particle sizes. This even distribution of particles of different sizes results in a dense mass upon compaction.
1.5 Submittals
A.Provide the following for information before delivering material to the project:
1.Supplier and source of materials.
2.Gradation analysis. Refer to AASHTO T 27 and T 11.
3.Soil classification when applicable. Refer to AASHTO M 145.
4.Maximum Dry Density and Optimum Moisture Determination
a.Use AASHTO T 180 Method D for A -1 soils and AASHTO T 99 Method D for all other soils.
B.Requests, for review, to use Untreated Base Course (UTBC) instead of granular borrow.
C.Engineering proposals for review for alternate materials or trench configurations for drainage pipe bedding and pipe backfill as outlined in this Section, 2.2 G. Include all of the following:
1.Stamped drawings and specifications signed and sealed by a Professional Engineer licensed in the state of Utah.
2.Evaluation of site specific conditions and surrounding soils, including potential for migration of fines.
3.A structural evaluation of the pipe support system for the proposed pipe that includes the pipe structural capacity and the depth of fill.
4.Complete bedding or backfill source information including gradation, soil classification, and laboratory testing reports.
D.Proposals, for review, to place an initial layer of granular material as a working platform.
1.6 Acceptance
A.Acceptance sampling and testing is according to UDOT Minimum Sampling and Testing Requirements.
B.The Engineer reserves the right to select and test material from any location at the construction site.
1.The Engineer will establish the limits of nonconforming material sampled non- randomly.
C.Remove nonconforming material and replace with acceptable material. Embankment, Borrow, and Backfill
Part 2 — Products
2.1 General
A.Provide materials free of contamination from chemical or petroleum products for embankment, borrow, and backfill placements .
1.Materials may include recycled Portland Cement Concrete.
2.Do not include asphalt pavement materials.
2.2 Materials
A.Borrow
1.Classifications A -1-a through A -4. Refer to AASHTO M 145.
B.Granular Borrow
1.Classification A -1-a. Refer to AASHTO M 145.
2.Non-plastic.
3.Meet the gradation requirements of Table 1 Table 1 Granular Borrow Gradation Sieve Size Percent Passing 4 inch 3 inch 1 inch 1/2 inch No. 4 No. 10 No. 40 No. 200 100 90 - 100 60 - 100 30 - 80 25 - 65 0 - 50 0 - 30 0 - 15
4.UTBC meeting the requirements of Section 02721, may be used, at no additional cost to the Department, upon authorization of the Engineer.
C.Granular Backfill Borrow
1.Classification A -1-a. Refer to AASHTO M 145.
2.Well- graded, 2 inch maximum.
D.Free-Draining Granular Backfill
1.Meet the gradation requirements of Table 2: Embankment, Borrow, and Backfill Table 2 Free Draining Granular Backfill Gradation Sieve Size Percent Passing 1½ inch 1 inch ¾ inch ⅜ inch 90-100 20-55 0-15 0-5
E.Embankment for Bridge
1.Classification A -1. Refer to AASHTO M 145.
2.3 inch maximum.
F.Embankment Material
1.Roadway excavation and other excavation material.
a.Do not include unsuitable materials such as organic, frozen, or contaminated soils.
b.Do not use rock or broken concrete materials with any dimension over 1 ft.
2.Borrow may be substituted for embankment material.
G.Drainage Pipe Bedding and Drainage Pipe Backfill
1.Classification A -1. Refer to AASHTO M145.
a.Well- graded material.
b.Maximum aggregate size is 1½ inches for plastic pipe, 2 inches for all other pipes.
2.Flowable fill. Refer to Section 03575.
a.Use only for drainage pipe backfill.
3.Other materials or trench configurations for drainage pipe bedding and backfill may be used when authorized. a. Native materials or uniformly graded materials enclosed in an appropriate drainage geotextile may be proposed.
Part 3 — Execution
3.1 General
A.Complete clearing, grubbing, stripping, and stockpiling topsoil , and any necessary excavation before placing material. Embankment, Borrow, and Backfill
B.Requirements when placing material during freezing or snowy conditions:
1.Do not place embankment, borrow, or backfill material on frozen or snow -covered areas.
a.Remove snow and frozen material and furnish specified materials that can be compacted to the specified density. 1) Measure removed material and provide quantities to the Engineer. 2) The Department does not pay for removed material or material replacement when it would otherwise meet specification requirements if unfrozen.
2.Do not deliver or use frozen material.
C.Use appropriate compaction equipment adjacent to pipes, abutments, back walls, approach slabs, wing walls, retaining walls, and other structures.
1.Expand the width of the trench to accommodate necessary compaction equipment.
2.Compact by hand areas where compaction equipment cannot compact the soil.
D.Compaction Requirements
1.Borrow, Drainage Pipe Bedding, Embankment Material, Embankment for Bridge, Granular Backfill Borrow and Granular Borrow
a.Compact each lift to a minimum average of 96 percent of maximum laboratory density with no single determination lower than 92 percent. 1) Use AASHTO T 180 Method D for A -1 soils and AASHTO T 99 Method D for all other soils to establish maximum laboratory density. 2) Maintain appropriate moisture for compaction during processing. Refer to Section 01572.
2.Drainage Pipe Backfill
a.Compact each lift to a minimum average of 92 percent maximum laboratory density with no single determination less than 90 percent. 1) Use AASHTO T 180 Method D for A -1 soils. 2) Maintain appropriate moisture for compaction during processing. Refer to Section 01572.
b.Meet the pavement section material density requirement for pipes that encroach into the pavement section or use flowable fill. Embankment, Borrow, and Backfill
3.Material with more than 30 percent retained on the ¾ inch sieve
a.Compact each lift to 100 percent of the developed field density. 1) The Department develops a field density compaction curve according to UDOT Materials Manual of Instruction Section 989.
4.Free-Draining Granular Backfill
a.Compact each lift to 100 percent of the developed field density. 1) The Department develops a field density compaction curve according to UDOT Materials Manual of Instruction Section 989.
E.Place an initial layer of granular material to act as a working platform over soft, wet ground when authorized by the Engineer.
1.Density requirements do not apply to the working platform except as specified in this Section, Paragraph 3.2 B.
2.Meet density requirements for embankment, borrow, or backfill placed above the working platform.
3.Do not place initial layer of embankment, borrow, or backfill until the Engineer inspects and verifies the working platform or foundation.
3.2 Embankment Material and Borrow Placement
A.Place embankment material or borrow or both in the embankment section with the highest quality material in the top portion of the embankment section .
B.Scarify and compact the top eight inches of the working platform or foundation to at least 90 percent of maximum laboratory density when the embankment height is 6 ft or less.
C.Break and scarify all underlying concrete pavement surfaces so that pieces do not exceed 1 ft 2 before placing material over an existing concrete pavement surface that is outside the limits of removal or excavation shown.
1.Remove other pavement surfaces that are not p ortland cement concrete.
D.Maintain Drainage
1.Grade and maintain the roadway to provide adequate drainage.
2.Maintain drainage pipes and drainage ditches or provide temporary facilities when interrupting items such as irrigation systems, sewers, and under -drains. Embankment, Borrow, and Backfill
E.Spread material uniformly in layers not exceeding 1 ft (uncompacted depth) and compact to the density requirements.
1.Reduce the lift thickness or modify operations if tests show unsatisfactory density.
2.Distribute larger particles so space exists for placing and compacting remaining material.
3.Do not place rocks or broken concrete larger than 4 inches within 1 ft of the subgrade surface.
F.Finish subgrade surface within ±0.2 ft of line and grade.
G.Do not use compacting equipment that causes shear failure in the constructed fill or backfill.
3.3 Granular Borrow, Granular Backfill Borrow, and Backfill
PLACEMENT
A.Compact material in maximum 6 inch layers (uncompacted depth) to the density requirement.
B.Finish surface within ± 0.1 ft of line and grade.
C.Backfill catch basins, cleanout boxes, manholes, drainage boxes, and diversion boxes with Granular Backfill Borrow unless otherwise specified or shown.
3.4 Drainage Pipe Foundation, Bedding, and Backfill Placement
A.Place in 6 inch layers (uncompacted depth) and compact to the density requirement.
B.Place uniform layers of drainage pipe backfill on both sides of the pipe and compact to the density requirement before placing successive lifts.
C.Fully compact the haunch areas.
3.5 Embankment for Bridge Placement
A.Construct bridge approach embankments from the existing ground up with the specified material to the limits defined in this Section and according to GW Series Standard Drawings.
1.Approach Embankments
a.Place embankment for bridge beneath the bridge except riprap or other described materials used for MSE walls. Embankment, Borrow, and Backfill
b.Place embankment for bridge to extend at least 150 ft from the centerline of the bridge abutment as measured along the approach roadway alignment and on the inside of abutments.
c.Use the described material throughout the length of the walls where retaining walls are located beyond this delineation.
2.Intersecting Roadway Embankments
a.Place embankment for bridge along the intersecting roadway alignment(s) at least 150 ft from the abutment centerline station as measured along the approach and intersecting alignments.
B.Spread embankment for bridge uniformly in layers not exceeding 1 ft (uncompacted depth) and compact to the specified density requirements before placing the next layer.
1.Reduce the lift thickness if tests show unsatisfactory density.
C.Finish surface within ±0.2 ft of line and grade.
3.6 Free -Draining Granular Backfill Placement
A.Compact material in 1 ft maximum layers.
B.Finish surface within ±0.2 ft of line and grade.
Source: Utah Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 234–241 of 1,331.