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The work covered by this section consists of the construction of a base composed of one or more natural materials proportioned and blended on the road, compacted, and shaped to conform to the lines, grades, depth, and typical sections shown on the plans or established by the Engineer.
All materials shall meet the requirements of Division 10 shown below:
Soil type base course Article 1010-4
530-3 PREPARATION OF SUBGRADE.
The subgrade shall be prepared in accordance with the provisions of Section 500.
(A) General:
The surface of the material sources shall be cleared and grubbed and thoroughly cleaned of all unsuitable material before beginning excavation. Disposal of material resulting from clearing and grubbing shall be in accordance with Article 2005. The removal and disposition of overburden shall be in accordance with Section 802.
Where payment is to be made by measuring the material in its original position, the Contractor shall notify the Engineer sufficiently in advance of beginning excavation of this material in order that the area may be staked and cross sectioned by the Engineer. No payment will be allowed for any material excavated prior to cross sections being taken. The excavation of the material shall be to the lines and slopes as staked by the Engineer and shall be done in an orderly manner to facilitate measurement at any time.
Where payment is to be made by truck measurement the Contractor shall furnish trucks with bodies suitable for accurate measurement. Trucks shall be loaded uniformly and in such a manner as to prevent spillage.
Where it is necessary to haul material over existing roads or streets, the provisions of Article 10515 will apply and the Contractor shall use all necessary precautions to prevent damage to the existing structures or pavement. The Contractor shall also conduct his hauling operations in such a manner as to not interfere with the normal flow of traffic and shall keep the traffic lanes free from spillage at all times.
(B) Department Furnished Sources:
Where material sources are furnished by the Department the location of such sources will be as designated on the plans or as directed by the Engineer.
The Department will furnish the necessary haul road right of way at locations designated by the Engineer. All haul roads required shall be built, maintained, and when directed by the Engineer, obliterated, at no cost to the Department. Where the haul road is to be reclaimed for cultivation the Contractor shall plow or scarify the area to a minimum depth of 8 inches.
Overburden shall be removed prior to the excavation of the base material when indicated by the plans or directed by the Engineer.
Where it is necessary to drain the material source the Contractor shall perform this work in accordance with Section 240.
The material source shall be left in a neat and presentable condition after use. All slopes shall be smoothed, rounded, and constructed not steeper than 2:1. Where the source is to be reclaimed for cultivation the source shall be plowed or scarified to a minimum depth of 8 inches, disc harrowed, and terraces constructed.
The sources shall be seeded and mulched in accordance with Sections 1620, 1660, 1661, or 1663, unless otherwise directed by the Engineer.
(C) Contractor Furnished Sources:
The approval of material sources furnished by the Contractor shall be subject to the following conditions:
1. The Contractor shall be responsible for acquiring the right to take the material and any rights of access that may be necessary; for locating and developing the source; and for any clearing and grubbing, removal of overburden, and drainage ditches necessary.
2. The Engineer will, upon the Contractor's request, sample and test the proposed source and give the Contractor written notice of the test results. The acceptance of the material shall be subject to the results of sampling and testing on the road as provided Article 5308.
3. Except where material has been obtained from a commercial source, or where the material source is constructed to serve as a pond, the following requirements will apply to the condition of the source after the material has been removed:
a. Where practical, the source shall be graded to drain.
b. The source shall be dressed and shaped to contours which are comparable to and blend in with the adjacent topography, but in no case will slopes steeper than 2:1 be permitted.
c. Seeding and mulching shall be performed over all areas of the source that have been disturbed by construction operations. This work shall be performed in accordance with Sections 1620, 1660, 1661, or 1663, and all applicable special provisions contained in the proposal. Upon written request by the Contractor, the Engineer may approve the use of vegetation other than seeding and mulching for erosion control.
d. Where it is necessary to drain the material source the Contractor shall perform this work in accordance with Section 240.
4. Before final acceptance of the project, the Contractor shall furnish the Engineer with a copy of a written release executed by the property owner or his authorized representative indicating that the final condition of the source is acceptable to the property owner.
(D) Substitute Sources:
Where the Contractor elects to substitute material sources for those provided by the Department, the provisions of Subarticle 5304(C) shall apply.
Material shall be deposited on the subgrade in such a manner that when all layers are spread, mixed, and compacted, the required depth of base material will be obtained. Where more then one type of material is to be used, each shall be spread uniformly over the subgrade prior to placing the next material.
Immediately after placing and spreading the base material, mixing operations shall begin. Mixing shall be done in a manner which will produce a thoroughly and uniformly mixed base course.
Compaction of the base shall be uniform throughout the depth and width of the base. Where the base is thicker than 8 inches, the base shall be spread and compacted in 2 layers approximately equal in thickness.
The base shall be compacted to a density equal to at least 100% of that obtained by compacting a sample of the material in accordance with AASHTO T99 as modified by the Department. Copies of these modified testing procedures are available upon request from the Materials and Tests Unit.
The base material shall be compacted at a moisture content which is approximately that required to produce the maximum density indicated by the above method. The Contractor shall dry or add moisture to the material when required to provide a uniformly compacted and acceptable base.
The base shall be finally shaped to conform to the lines, grades, and typical sections shown on the plans or established by the Engineer. Care shall be taken to prevent the formation of slippage planes in the surface. All soft or unstable areas shall be thoroughly dried, remixed, or removed and replaced.
530-8 SAMPLING, TESTING, AND ACCEPTANCE.
Where the depth of the base is such that the placement of more than 1 layer is required for proper mixing and compacting, each layer of material shall have been sampled, tested, and approved prior to placing additional base material thereon.
Samples will be taken from the road immediately after the base material has been spread, mixed, and shaped to a true cross section. Sampling and testing for acceptance will be as hereinafter provided.
Where the roadway base is placed in widths 27 feet or less, a sampling unit shall consist of 500 linear feet. Where the base is placed in widths over 27 feet, a sampling unit shall consist of 1,500 square yards. As an exception to the above, when the base course is constructed utilizing materials in the existing subgrade the sampling units will be reduced to one half the size indicated above. A sampling unit on a shoulder or widening of 12 feet or less shall consist of 1,000 linear feet.
One sample will be taken from a location selection by the Engineer in each unit. The sample will be taken by cutting 3 cores for the full depth of the base course, one on the center line and one approximately 3 feet from each edge, and combining the material as one sample representing the material in that unit.
If the sample tested fails to meet specification requirements, 2 check samples shall be obtained, one on each side of the original sample at 50 feet spacing. Both of these samples shall meet specification requirements or the unit will be rejected.
Where a unit is rejected, no further samples will be taken from that unit until the material is either corrected by the addition and mixing of suitable material or the rejected material is removed and replaced.
Where the material source is furnished by the Contractor and the Engineer permits the Contractor to correct a rejected unit by the addition and mixing of corrective material, all work necessary due to the addition of the corrective material shall be performed by the Contractor at no cost to the Department.
Where the material source is furnished by the Contractor and the rejected unit is in a final layer of base, any material added to correct gradation shall be furnished and incorporated by the Contractor at no cost to the Department.
Resampling of a corrected or replaced unit will be preformed in the same manner as original sampling.
After final shaping and compacting of the base, the Engineer will check the surface of the base for conformance to the grade and typical section and determine the base thickness.
The thickness of the base shall be within a tolerance of plus or minus 1/2 inch of the base thickness required by the plans.
The maximum differential between the established grade and the base within any 100 foot section shall be 1/2 inch.
Where sampling and testing indicate that additional material must be added to the base to produce the required quality, the Contractor shall add the required material, remix, recompact, and reshape the base to the required lines, grades, and typical sections.
Where the material source is furnished by the Contractor, the work of reconditioning shall be performed by the Contractor at no cost to the Department.
Where the base material is placed in a trench section, the Contractor shall provide adequate drainage through the shoulders to protect the subgrade and base until such time as shoulders are completed.
The Contractor shall maintain the surface of the base by machining, watering, and rolling or dragging when necessary to prevent damage to the base by weather or traffic.
Within 24 hours of completion of the base the Contractor shall prime the base slopes where required or, where prime is not required, shall place sufficient shoulder material against the edges of the completed base to protect the base.
Where the base or subgrade is damaged due to negligence on the part of the Contractor, the Contractor shall repair the damaged area; reshape the base to the required lines, grades, and typical sections; and recompact the base to the required density at no cost to the Department.
(A) Soil Type Base Material:
The quantity of soil type base course material to be paid for will be the actual number of cubic yards or tons of base course material which has been incorporated into the completed and accepted work except that no measurement will be made of any additional material which the Engineer has permitted the Contractor to incorporate into a final base layer in the work of reconditioning where the Contractor has furnished the material source.
Measurement of the base course material will be made in accordance with one of the following methods:
1. When the material is to be measured in its original position, measurement will be made by cross sections and computations will be made by the average end area method. No measurement will be made of any material excavated prior to cross sections being taken.
2. When the material is to be measured in trucks, the level to which each truck is to be loaded will be measured by the Engineer and each truck shall be suitably marked to indicate the loaded level. Each truck shall bear a suitable mark or number for identification. Each truck shall be loaded to at least its measured load level when it arrives at the point of delivery. The recorded quantity of material will be adjusted by making a 25 percent deduction to allow for shrinkage, and the adjusted quantity will be the quantity to be paid for.
3. Where the contract calls for the material to be paid for by the ton, the material will be measured by being weighed in trucks on certified platform scales or other certified weighing devices. No deduction will be made for any moisture contained in the material at the time of weighing.
(B) Reconditioning Road:
When material sources are furnished by the Department and the Engineer directs the incorporation of additional material into a rejected sampling unit, the work of reconditioning as provided in Article 53010 will be measured as provided below.
When material sources are furnished by the Contractor, no measurement of reconditioning will be made.
The quantity of reconditioning to be paid for will be the actual number of units of 1,000 square yards of base course over which the work of reconditioning has been acceptably performed. The length will be the actual length measured along the centerline of the surface of the base. The width will be the width required by the plans or as directed by the Engineer measured across the top surface of the base.
The quantity of base course, measured as provided in Subarticle 53012(A), will be paid for at the contract unit price per cubic yard or ton for "Soil Type Base Course, Type________."
The quantity of reconditioning, measured as provided in Subarticle 53012(B), will be paid for at the contract unit price per 1,000 square yards for "Reconditioning, Soil Type Base Course."
Where the material source has been furnished by the Department, payment for clearing and grubbing the source will be made as provided in Article 2007, payment for removal and disposal of overburden will be made as provided for unclassified excavation in Article 2258, payment for draining the source will be made as provided in Article 2405, and payment for seeding and mulching the source when required will be made as provided in Article 16609.
Where the material source has been furnished by the Contractor, no separate payment will be made for clearing or grubbing, removal and disposal of overburden, draining the source, or seeding the mulching as such work will be considered as incidental to the work covered by this section.
The above prices and payments will be full compensation for all work covered by this section including but not limited to furnishing the source of material; building, maintaining, and obliterating haul roads; clearing and grubbing the material source; removal and disposal of overburden; excavation; hauling; spreading materials; mixing; compacting; shaping; reconditioning; maintaining the base; restoration of the source and haul roads to an acceptable condition; and seeding and mulching the source.
Payment will be made under:
Soil Type Base Course, Type __________ Cubic Yard
Soil Type Base Course, Type __________ Ton
Reconditioning, Soil Type Base Course 1,000 Square Yards