- 167 - SECTION 307 -- FOUNDATION COURSE
307.01 Description
1.The foundation course is a laye r of compacted material conforming to the lines, grades, and dimensions shown in the contract. The foundation course shall be built on a finished subgr ade. The Contractor shall complete the following requirements under the foundation course bid items including but not limited to:
a.Adjust grade lines to meet intersections, pavements, bridge ends, railroad crossings, or any other physical features designated by the Engineer.
b.Process the source material.
c.Placement of the foundation course.
d.Compaction of the foundation course.
e.Profiling the foundation course. f. Disposal of excess material after profiling is completed. 2. The types of foundation course are: a. Bituminous.
b.Crushed concrete.
c.Aggregate Foundation Course - D.
307.02 Material Requirements
1.a. All samples, including fiel d samples, will be washed sieve. All samples will be taken from the project grade prior to the spreading operations.
b.The Contractor shall handle all material in such a manner that prevents contamination.
2.Bituminous Foundation Course: a. Material used in constructing bituminous foundation course shall consist of salvaged bituminous material. The source of the salvaged bituminous material will be described in the contract.
b.All salvaged bituminous material must be less than 3 inches (75 mm) in maximum dimension and shall not contain more than 5% by weight of material retained on a 2 inch (50 mm) sieve just prior to its use.
1.Contractor Production (i) All salvaged bituminous material produced by the Contractor from pavement removal or by cold milling material from the existing pavement structure on the proj ect, whether hauled directly to the site of use or temporarily stockp iled, shall be screened to meet the requirements of Paragraph 2.b. (ii) If, after screening, ther e is insufficient material to produce the plan quantity, the Engineer may order the oversized salvaged bituminous material to be further proces sed at no cost to the State prior to delivery to the roadway. Processing shall mean crushing, pulverizing, re-screening, or a combination of these methods.
307.02 Foundation Course
- 168 - (iii) On projects that allow multiple foundation course materials to be used, the Engineer ma y direct that salvaged bituminous material continue to be placed as bituminous foundation course to the extent this material is available and can be utilized on the project. (iv) Unless otherwise shown in the contract, all Contractor produced salvaged bituminous material, including oversized, remaining at the end of the bituminous foundatio n course operation shall become the property of the Contractor and removed from the project.
v.Asphaltic concrete millings shall be free of deleterious matter as determined by the Engineer.
2.Department Provided Stockpiles (i) If the salvaged bituminous material is to be obtained from existing stockpiles described in the contract, the salvaged bituminous material shall be screened to meet the requirements of Par agraph 3.b. prior to delivery to the roadway. Any oversized bituminous material remaining from the screening operation shall rema in the property of the Department. (ii) If, after screening, ther e is insufficient material to produce the plan quantity, the Engineer may order the oversized bituminous material to be further processed prior to the delivery to the roadway. Processing shall mean crushing, pulveriz ing, re-screening, or a combination of these methods. This will be paid for as extra work.
3.Crushed Concrete Foundation Course: a. Material used in constructing crushed concrete foundation course shall consist of processed and stockpiled concrete pavement. The source of the materials for the crushed concrete will be described in the contract. Crushed Concrete shall be free of deleterious matter as determined by the Engineer.
b.All samples will be taken from the project grade prior to spreading and trimming. The crushed concrete gradation shall be determined as described in NDOT T 27 (w ashed test). The target gradation requirement for the crushed concrete foundation course is shown in Table
307.01 Material represented by samples with 15% or more passing the No.
200 (75 µm) sieve will be subject to removal.
c.Material gradation will be accepted by the table below on a lot basis of 2,500 cubic yards on the av erage of 5 consecutive tests, one for each 500 cubic yard sublot. If at the end of the project, the final lot consists of less than 2,500 cubic yards, a minimu m of 3 samples, or 1 sample for each 500 cubic yards or fraction thereof, whichever is greater shall be taken and tested and acceptance based on the average of those tests. Table 307.01 Crushed Concrete Foundation Course Gradation Requirements Sieve Size (Percent Passing) 1½ inch (37.5 mm) 100 minimum ¾ inch (19.0 mm) 85 maximum No. 4 (4.75 µm) 20 to 50 No. 200 (75 µm) 0 to 8 Foundation Course 307.03 - 169 - d. Moisture content shall be no higher than necessary to facilitate compaction to required stiffness.
4.Aggregate Foundation Course-D
a.Aggregate Foundation Course-D shall be a non-recycled virgin material.
b.Aggregate shall conform to the quality requirements of Section 1033.
c.At least 14 days befor e beginning foundation course production, the Contractor shall subm it a proposed mix design along with a 50 pound (23 kg) sample of each aggreg ate to the Engineer for approval. The mix design will:
1.Result in an aggregate mix that meets the gradation requirements of Table 307.02.
2.Propose single defined values for the percentage passing each sieve on the gradat ions of Table 307.02.
3.Include the average aggregate gradations used to calculate the mix design.
4.Create a fine aggregate angularity value of 43.0 or greater. The specific gravity for calculat ion of the Fine Aggregate Angularity (FAA) shall be determined on a combined aggregate sample of the material passing the No. 8 (2.36 mm) sieve and retained on the No. 100 (150 µm) sieve as defined in AASHTO T 304 Method A, except the s pecific gravity material shall be washed over the No. 100 (150 µm) sieve.
d.The Engineer will determine t he specific moisture content and rolling pattern needed for optimal stiffness for the proposed foundation course design. Table 307.02 Aggregate Foundation Course-D Gradation Requirements Sieve Size Target Value Tolerance (Percent Passing) 1/2 in (12.5 mm) 100 0 3/8 in (9.5 mm) 100 -4 No. 4 (4.75 mm) 93 ±4 No. 10 (2.0 mm) 55 ±10 No. 30 (600 µm) 25 ±5 No. 40 (425 µm) 20 ±4 No. 200 (75 µm) 3 ±3
307.03 Construction Methods
1.Bituminous Foundation Course: a. The Contractor shall load the bituminous material at locations shown in the contract, haul, screen, distribute, spread, and compact the salvaged bituminous material to form a firm and stable foundation for the construction of the surfac e. The quantity of bituminous material placed shall be adequate to provide for consolidation and profiling of the entire surface after compaction.
307.03 Foundation Course
- 170 - b. The Contractor shall roll t he bituminous foundation course until no further compaction can be obtai ned and roller marks are eliminated.
1.The Department will establish a rolling pattern and set a deflection target value.
2.The Department shall monitor the rolling pattern with a light weight deflectometer and as conditions change the rolling pattern may be adjusted by the Engineer to attain opt imal stiffness. Additional testing of separately placed irregular areas shall be performed as directed by the Engineer.
3.The Contractor shall take immediate action to adjust the rolling pattern when the Engineer determines that the foundation course stiffness variance is outside the tole rance of the deflect ion target value.
2.Crushed Concrete Foundation Course:
a.The Contractor shall crush, lo ad, haul it to the project site, and distribute, place, and compact the cr ushed concrete to form a foundation course as shown in the contract.
1.The Contractor shall roll the crushed concrete foundation course until no further compaction ca n be obtained and roller marks are eliminated.
2.The Department will establish a rolling pattern and set a deflection target value.
3.The Department will monitor the rolling pattern with a light weight deflectometer. Additional testi ng of separately placed irregular areas will be performed as directed by the Engineer.
4.The Contractor shall take immediate action to adjust rolling pattern when the Engineer determines that the foundation course stiffness variance is outside the tole rance of the deflect ion target value.
5.The accuracy of the pre paration of the subgrade and the profiling of the crushed concrete found ation course will be such that the profile grade will not vary from t he contract by more than 1/2 inch.
3.Aggregate Foundation Course – D: a. The Contractor shall place, compact, and profile the foundation course as shown in the contract.
b.The foundation course shall be spread in a uniform layer and compacted to optimal moisture as determined by AASHTO T 99.
c.The Department will establish a rolling pattern and set a deflection target value.
d.The Department will monitor the rolling pattern with a light weight deflectometer and as conditi ons change the rolling pattern may be adjusted by the Engineer to attain optim al stiffness. Additional testing of separately placed irregular areas will be performed as directed by the Engineer.
e.The accuracy of the preparation of the subgrade and the profiling of the aggregate foundation c ourse will be such that the profile grade will not vary from the co ntract by more than 1/2 inch. Foundation Course 307.04 - 171 - 4. Profiling:
a.After the foundation course has been compacted and before the surface is profiled, the thickness shall be measured.
b.If the thickness of the compacted material is insufficient to permit profiling, the deficiency shall be corrected by the placement and compaction of additional material. An adequate bond shall be established between the compacted surface and the new material. A tack coat may be required for cohesion as directed by the Engineer.
c.The profiling operation may be accomplished by milling, if necessary.
d.During the profiling operati on, the control of grade and cross slope shall be maintained by the Contractor.
e.The accuracy of the preparation of the subgrade and the profiling of the bituminous foundation course will be such that the profile grade will not vary from the co ntract by more than 1/2 inch.
f.The grade stakes placed for controlling the profiling operation shall be protected for controll ing the pavement operation.
5.Surface Protection: a. At the Contractor's opti on, a fog seal may be applied in accordance with the requirements of Section 513.
b.The Contractor shall only allow necessary local traffic and essential construction equipment on the foundation course.
c.The Contractor shall repair or replace marred, distorted, or otherwise damaged foundation course at no additional cost to the Department.
6.Material from the profiling opera tion may be reused if it meets the material requirements. Material not meeting the material requirements shall be wasted and removed from the project.
307.04 Method of Measurement
1.The foundation course will be measured for payment either by weight [tons (megagrams)] or by the square yard (square meter).
2.Foundation course paid for by the square yard (square meter) is not measured directly. The overlying pave ment is measured, and the pavement quantity is used as the foundation course quantity.
3.a. Screening of salvaged bituminous material will not be measured for payment.
b.Processing of Contractor produced salvaged bituminous material, ordered by the Engineer, which contains excessive oversized material due to the Contractors production methods, will not be measured for payment.
307.05 Foundation Course
- 172 - 307.05 -- Basis of Payment
1.Pay Item Pay Unit Aggregate Foundation Course ______ Ton (Tn) [Megagram (Mg)] Aggregate Foundation Course ______ Square Yard (SY) [Square Meter (m2)] Bituminous Foundation Course ______ Square Yard (SY) [Square Meter (m2)] Crushed Concrete Foundation Square Yard (SY) Course ______ [Square Meter (m2)]
2.a. If a foundation course is 0.05 to 0.10 foot (15 mm to 30 mm) less than the specified thickness, it shall be removed and replaced; or, at the Contractor's option, the material may be left in place and paid for at 40% of the bid price for the deficient areas. The area of the deficient section shall be determined by the Engineer.
b.Foundation course more th an 0.10 foot (30 mm) less than the specified thickness shall be removed and replaced at no additional cost to the Department. The extent of the area to be corrected will be determined by the Engineer.
3.Application of a tack coat shall be subsidiary to the item "Bituminous Foundation Course _____".
4.If the Contractor elects to apply a fog seal, it shall be at no cost to the Department.
5.All water applied to foundation course will not be measured for payment but will be considered subsidiary to the relevant foundation course bid item.
6.Screening of salvaged bituminous material shall be considered subsidiary to the bituminous foundation course item.
7.Processing of salvaged bituminous material, ordered by the Engineer, which contains excessive over size material due to the Contractors production methods, shall be considered subsidiary to the bituminous foundation course item.
8.If the Contractor is required to reprocess the oversized bituminous material from State stockpiles, the work of reprocessing will be paid for as "extra work".
9.Payment is full compensation for all work described in this Section. - 173 - SECTION 308 -- MEDIAN CONSTRUCTION
308.01 Description
1.The Contractor shall complete the following requirements under the "Median Construction" bid item:
a.Furnish the embankment material as necessary to conform to the contract.
b.Haul, compact, blade, and shape the material to conform to the contract’s typical cross sections and compaction requirements.
308.02 Material Requirements
1.The Contractor shall be required to obtain and furnish material unless otherwise shown in the contract.
2.Soil required for embankments shall meet the requirements of Subsection 205.02.
308.03 Construction Methods
1.The Contractor shall construct m edians as indicated in the contract.
2.The work shall be performed in accordance with the requirements of Subsection 304.03.
308.04 Method of Measurement
1.Median Construction shall be measured in stations of 100 feet (100 meters), regardless of width or th ickness. Stations shall be measured horizontally along the project center line between the beginning and ending points.
308.05 Basis of Payment
1.Pay Item Pay Unit Median Construction Station (Sta) [Station (StaM)] Water 1,000 Gallons (MGAL) [ k i l o l i t e r s ( k L ) ]
2.Payment is full compensation for all work described in this Section.
Referenced in this section
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Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 201–206 of 1,048. View official source ↗