CATEGORY 200 GRADING SECTION 204 — EMBANKMENT AND SUBGRADE
204.01 Description
Construct embankment and subgrade using suitable material obtained from roadway, structure, borrow, and other excavation included in the Contract. Place, process, and compact material to the specified line and grade.
204.02 Materials
Unless otherwise specified, use soils and soil aggregate mixtures that meet the common borrow requirements specified in Section 916.
204.02.01 Rock. Rock may be used in embankments, if individual pieces do not exceed 24 in. in
any dimension. Larger size rocks may be wasted with the approval of the Engineer. 204.02.02 Frozen Material. Refer to 201.03.05. In addition, do not cover any material that freezes after being placed in the embankment until it has thawed. 204.02.03 Embankment Adjacent to Structures. The Engineer may require the use of specially selected material adjacent to structures to protect the structure from damage. Do not use rock. At locations of pile supported foundations, use embankment material that will allow piles to be easily driven.
204.02.04 Geotextile Inclusions. Refer to 919.01 Class SD Type II Non-Woven.
204.03 Construction
204.03.01 Embankment Foundation
a.Foundation Material. The Engineer will inspect and approve the area prior to construction of the embankment. Remove topsoil, root mat, and unsuitable material to the depth directed.
b.Embankment Over Existing Pavement. When embankment is being placed in an area of existing pavement, remove the bound asphalt or concrete pavement materials prior to placing embankment material. Leave the unbound pavement materials in place to aid in maintaining the stability of the area. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
c.Test Rolling. Unless exempted by the Engineer, test roll embankment foundation with a 35 ton pneumatic tired roller, hauling units with a weight of 35 tons, or other equipment as approved. In case of a failed test roll, undercut unstable areas and backfill with Select Borrow or other suitable material; bridge with a thick embankment lift of Select Borrow or other suitable material and provide drainage; or other suitable treatment as determined by the Engineer at the time of construction. Embankment foundation areas that may be exempted from test rolling include areas that do not require grubbing and areas impractical to access with test rolling equipment.
204.03.02 Placing and Spreading. Place the material in horizontal layers across the full width
of the embankment. Maintain an adequate crown to provide drainage at all times. Maintain side slopes at the specified slope throughout the progress of the work.
a.Embankment on Unstable Ground. When embankment is to be constructed on ground that will not support the weight of the construction equipment, the first layer of the fill may be constructed by depositing material in a layer no thicker than that required to support the equipment. Place subsequent layers as specified in (b).
b.Earth Embankment. Except when specified, do not place layers exceeding 8 in. compacted depth.
c.Rock Embankment
1.Determine the thickness of layers by the size of the rock or a 24 in. maximum depth, whichever is less. Where the embankment is less than 6 ft below the subgrade at the profile grade line, place the material in layers not exceeding 8 in. compacted depth. Solidly fill and choke these layers with spalls, rock dust, or earth. Fill and compact each layer before placing the next layer.
2.Place the rock material to a uniform top surface, determined by connecting with straight lines the points on the typical cross section that are 9 in. below any median ditch invert and 9 in. below the bottom of the pavement structure and then sloping downward and outward under the shoulders at the rate of 3/4 in. per ft to the outer slope of the embankment.
3.Unless otherwise specified, construct the remaining upper portion of the embankment, using suitable earth that is free from stones retained on a 3 in. sieve.
204.03.03 Benching. When placing and compacting embankment on hillsides or against existing
embankments, continuously bench the slopes where the slope is steeper than 4:1 when measured at right angles to the roadway. Perform the benching operation as the embankment is constructed in layers. Maintain a bench width of at least 5 ft. Begin each horizontal cut at the intersection of the original ground and the vertical sides of the previous cut. If the material cut from the benches meets embankment requirements, compact this material along with the new embankment material. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
204.03.04 Compaction. Immediately after spreading each layer of fill, compact the material with
approved equipment. Perform all rolling in a longitudinal direction along the embankment. Begin at the outer edges and progress towards the center. Vary the travel paths of traffic and equipment over the width of the embankment to aid in obtaining uniform compaction. Compact the material that is 1 ft below the top of subgrade to at least 92 percent of the maximum dry density according to T 180. Compact the top 1 ft to at least 97 percent of the maximum dry density. Determine in-place density according to MSMT 350 or MSMT 352. When necessary, add water or dry the layer in order to compact to the required density. When finally compacted to the required density, the resultant moisture content of embankment material shall be within two percentage points of optimum. Provide a portland cement concrete compaction block having dimensions 18 in. x 18 in. x 9 in., weighing at least 200 lb, and with one 18 in. x 18 in. level and broomed working surface.
204.03.05 Stability of Embankments. Remove and replace with acceptable material any
embankment or portion thereof that has been constructed with unsuitable material. Remove and replace unstable material and remove and replace portions of the embankment that become unstable or displaced as the result of the construction operations.
204.03.06 Protection of Structures and Utilities During Construction. Protect all structures
and utilities from any damage in the handling, processing, or compacting of embankment or backfill material. Exercise caution near arches, retaining walls, culverts, and utility trenches to prevent undue strain or movement. In areas where rollers cannot be used, refer to Section 210.
204.03.07 Subgrade. After all cuts, embankment, and backfilling have been substantially
completed, construct and shape the subgrade to the specified cross section. Test roll the subgrade with a 35 ton pneumatic tired roller, or hauling units with a weight of 35 tons, or other equipment as approved. Undercut unstable areas and backfill with Geosynthetic Stabilized Subgrade Using Graded Aggregate Base as specified in Section 211, or other specified material.
204.03.08 Maintenance. Maintain the embankment and subgrade until final acceptance. Use
acceptable material from excavation or borrow to replace embankment and subgrade material that may be lost or displaced as a result of natural causes such as storms and cloudbursts, or as a result of unavoidable movement or settlement of the ground or foundation upon which the embankment and subgrade is constructed. Maintain ditches and drains at all times. Keep all traffic on the embankment and subgrade to a minimum. Remove ruts that are 2 in. or more in depth by reshaping and recompacting.
204.03.09 Placement of Geotextile Inclusions. Furnish and install geotextile inclusions as a
compaction aid in fill embankments where the embankment is at least 10 ft high and 10 ft wide to the lines and grades shown on the Contract Documents or as directed. Install according to the manufacturers’ recommendations. Geotextile inclusions shall be minimum 12 ft in width. The vertical spacing of the geotextile inclusions shall be 3 ft. Place geotextile inclusions concurrently with the embankment material. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS Unroll the geotextile onto the horizontal fill surface such that the edge of the geotextile is within 1 ft of the finished slope face. Pull the geotextile tight prior to backfilling. Secure the geotextile in position by suitable means according to the manufacturer’s recommendations until the subsequent soil layer can be placed. Do not allow tracked construction equipment to operate on the exposed geotextile. Place a minimum of 6 in. of uncompacted fill on the geotextile before operating tracked vehicles on it. Minimize turning of tracked vehicles to prevent displacement of the geotextile or the fill. Rubber-tired equipment may pass over the exposed geotextile at speeds of less than 10 mph. Avoid sudden braking and sharp turns.
204.04 Measurement and Payment
Embankment, subgrade, and all necessary work will not be measured but the cost will be incidental to the Contract unit price per cubic yard for the pertinent Class of Excavation. The payment will be full compensation for the formation, sprinkling, compacting, test rolling, shaping, scarifying, breaking or removing of the existing pavement, sloping, trimming, finishing, maintaining embankments and subgrade, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
204.04.01 Replacement of material lost as a result of natural causes will be measured and paid for
at the Contract unit price per cubic yard for the pertinent Class of Excavation item or as directed.
204.04.02 Compaction by means of mechanical tampers or vibratory compactors will not be
measured but the cost will be incidental to the pertinent Class of Excavation item.
204.04.03 Removal of bound pavement materials will be paid for as Class 1 Excavation. 204.04.04 Geotextile inclusions will be measured and paid for at the Contract unit price per square
yard of geotextile placed.
204.04.05 Undercutting will be paid for as specified in Section 201 as Class 1-A excavation. 204.04.06 Backfill will be measured and paid for as specified in Section 203.
2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS 205 — TEST PIT EXCAVATION 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS CATEGORY 200 GRADING SECTION 205 — TEST PIT EXCAVATION
205.01 Description
Excavate and backfill test pits to determine the location of underground structures and utilities.
205.02 Materials
Not applicable.
205.03 Construction
Determine the location of underground structures and utilities by test pit excavation prior to excavation operations. Excavate test pits at the location and to the size and depth authorized. Backfill test pits as specified in Section 210.
205.04 Measurement and Payment
Test Pit Excavation will be measured and paid for at the Contract unit price per cubic yard for the material actually removed from within the limits specified. The payment will be full compensation for all excavation, tamped backfill, and all material, labor, equipment, tools, and incidentals necessary to complete the work. Any pavement to be replaced will be measured and paid for as specified in Section 106.
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 296–299 of 1,113.