A.
After completion of the rough grade and prior to laying of the foundation course, the subgrade shall be shaped to line and grade thoroughly compacted with an approved vibratory roller weighing not less than 10 tons. All hollows and depressions which develop under rolling shall be filled with acceptable granular material and again rolled, this process to be continued until no depressions develop. The subgrade shall not be muddy or otherwise unsatisfactory when the foundation course is laid upon same.
B.
Any soft or unstable portions of the subgrade which develop under the roller shall be completely excavated and removed from the right-of-way and shall be replaced with acceptable granular material and the area regraded and compacted as above.
C.
The following definitions of soil types are hereby adopted by the Town, as referenced in the most current edition of "Standard Specifications, Construction and Materials" of the New York State Department of Transportation, Design and Construction Division:
Type | Definition |
|---|---|
CA-3 | Coarse aggregate per NYSDOT, Sec. 703, Size Designation 3A |
CL | Clay per ASTM D 2487, Classification CL |
DG-1 | Dense-graded aggregate per NYSDOT Sec. 304; Type 4 |
DG-3 | Dense-graded aggregate per NYSDOT Sec. 302; granular material |
E | Selected earth having an in-place density of at least 100 PCF; less than 4% organic materials; free of peat, frozen materials, deleterious materials, and rocks over 4 inches in diameter |
GM-1 | Granular material per NYSDOT Sec. 304, Type 2 |
GM-2 | Granular material per NYSDOT Sec. 304, Type I |
GM-2A | Granular material per NYSDOT Sec. 304, Type I except maximum size 1/2 inch |
NS | Natural sand; clean, hard, durable particles of sand resulting from natural disintegration of rock, well-graded from coarse to fine with 100% passing the 1/4-inch sieve and not over 7% passing the No. 200 sieve |
PG | Pea gravel; clean, hard, durable, free flowing, naturally rounded particle of rock, free from clay lumps, with 100% passing the 3/8-inch sieve and not over 5% passing the No. 8 sieve |
RIP-RAP | Sound, durable boulders or rock, well graded, of sizes 8 inches minimum to approximately 36 inches maximum in either dimension, weighing not less than 50 pounds each, except as needed for filling in spaces between the larger pieces |
TOPSOIL | |
1. For removal | A surface soil layer containing organic matter such as roots or humus, and having a weight loss of 5% or more on ignition at 600º C. for three hours when compared with the oven dry weight as determined by ASTM D 2216-80, or most current designation |
Refer to § 199-24 for topsoil stripping requirements | |
2. Project-usable | Selected, fertile, friable loam, stripped from the upper 12 inches and having a weight loss of 6% to 12% when tested per 1. above; free from subsoil, heavy clay clumps, stones, grass clumps, roots larger than 1/8 inch in diameter, or other objectionable matter such as garbage or rubbish |
Refer to § 199-24 for topsoil placement requirements | |
UNSUITABLE SOIL | Any soil not meeting the requirements of the material definitions in this section |
D.
Material use and compaction requirements; descriptions of density and compaction.
(1)
Maximum density: the dry density at optimum moisture content per ASTM D 1557-78 (Modified Proctor), or most current designation.
(2)
In-place density: The dry density, dry unit weight, or dry unit mass as applicable per ASTM D 1556-82, D 2167-84, D 2922-81 and D 3017-78, or D 2937-88 as appropriate.
(3)
Required compaction: the ratio of in-place density to maximum density, expressed as a percentage.
(4)
Compacted: Material at the required compaction or higher.
(5)
Subgrade: The in-place compacted soil, aggregate, fill or backfill which receives subsequent construction such as culverts, utilities, structures or overlying courses.
(6)
Exterior: any area outside of structure walls or foundation lines.
(7)
Interior: any area within trenches or below structures or foundations.
E.
Moisture content and tolerance. Materials to be compacted shall contain the amount of moisture to obtain the required compaction uniformly throughout its depth. The contractor shall add moisture to or dry out soils or aggregates being used so that the soils or aggregates are within 2%, plus or minus, of the optimum moisture content during compaction.
F.
Schedule. When using hand-guided compaction equipment or hand tamping tools, the maximum loose measure lift shall be four inches in lieu of maximum lifts specified on the following table, which continues through two pages, when using machine compaction:
Application | Type | Maximum Lift Thickness in Inches - Loose Measure For Machine Compaction | Required Compaction Percent | ||
|---|---|---|---|---|---|
1. | FILL | ||||
Interior areas to bottom of aggregate base, and exterior to 3 feet outside structure wall lines | GM-2 | 8 | 95% | ||
Under exterior slabs, pavements, or other improved surfaces of concrete, bituminous, or aggregate beyond 3 feet outside any building wall lines | |||||
a. | More than 18 inches below subgrade | E | 8 | 90% | |
b. | Subgrade to 18 inches below subgrade | E | 8 | 95% |
Other locations | E | 12 | 90% | ||
2. | BACKFILL (TO SUBGRADE) | ||||
Under portland cement or bituminous concrete, or aggregate surfaced areas, such as roads, walks, and parking lots, including work in existing or future locations | GM-2 | 8 | 95% | ||
Where trench shoulder adjacent to areas described above is 2 feet or less | GM-2 | 8 | 95% | ||
Where new work crosses under previously constructed utilities | GM-2 | 8 | 95% | ||
Other exterior areas not described above | E or GM-2 | 8 | 90% | ||
Interior areas to bottom of aggregate base, and exterior to 3 feet outside any building wall lines | GM-2 | 12 | 95% | ||
3. | SUBGRADE: Compaction same as noted for fill or backfill for same type of area | ||||
4. | AGGREGATE SUBBASE | ||||
Bituminous pavement | GM-2 | 8 | 95% | ||
5. | AGGREGATE BASE | ||||
Bituminous pavement | DG-1 | 8 | 95% | ||
Concrete pavement | DG-1 | 8 | 95% | ||
Concrete slabs | GM-1 | 12 | 95% | ||
Walks | GM-2 | 12 | 95% | ||
6. | EMBEDMENT (BEDDING AND INITIAL BACKFILL) | ||||
Culvert pipes, but excluding underdrains | GM-2A | 6 | 90% | ||
Catch basins | GM-2A | 6 | 90% | ||
Headwalls | GM-2A | 8 | 95% | ||
* Consolidate the material thoroughly, by probing or tamping near the catch basins, culverts, and utilities as necessary, giving special attention to bedding under these structures. | |||||
Direct burial cable and direct burial conduit | NS | 6 | 90% | ||
Underdrains | CA-2 | 6 | 90% | ||
7. | CLAY SEAL | ||||
At ends of culverts | CL | 6 | 90% | ||
Under slabs or pavements of concrete, bituminous or aggregate, as a seal for tops of excavations where shown on the approved plans | CL | 6 | 95% | ||
All other exterior locations as a seal for tops of excavations where shown on the approved plans | CL | 8 | 90% | ||
8. | AGGREGATE SURFACE | ||||
General purpose | DG-3 | 6 | 95% | ||
9. | TOPSOIL | (Pro- ject- usable) | 8 | Same as adjacent natural soil | |
10. | RIP-RAP | For use in erosion control, at end of culvert end sections, and to line drainage ditches | |||
G.
Field quality control. Fill and subgrade materials shall be subject to compaction tests, unless determined not necessary by the Highway Superintendent or Town Engineer. The following standards shall apply:
(1)
Refer to § 199-26D for the standards for test methods to be used for field quality control, as necessary.
(2)
The testing agency for field quality control of operations shall determine the compaction of all material placed and shall conduct the following minimum number of in-place density tests after monitoring the placing and compacting of each lift.
(3)
If compaction tests indicate that a layer has not been brought to the required compaction, recompact the area, prior to placement of additional material, until the required compaction is obtained. If the layer has been covered by a subsequent operation, remove such material before recompacting the defective layer. All tests results must meet with the approval of the Highway Superintendent or Town Engineer.