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The work covered by this section consists of furnishing and operating, at the direction of the Engineer, heavy pneumatic tired compaction equipment for compacting the roadbed and testing the roadbed for stability and uniformity of compaction.
The equipment shall consist of 4 rubber tired wheels mounted on a rigid steel frame. The wheels shall be evenly spaced in one line across the width of the roller and shall be arranged in such a manner that all wheels will carry approximately equal loads when operated over an uneven surface. The maximum center to center spacing between adjacent wheels shall not exceed 32 inches. The compacting equipment shall have a suitable body for ballast loading with such capacity that the gross load shall be from 48 to 50 tons unless otherwise permitted by the Engineer in writing. Other equipment of equal or better effectiveness may be substituted with written permission from the Engineer.
The tires shall be operated at inflation pressures between 68 to 72 pounds per square inch unless otherwise permitted by the Engineer in writing. The tires shall be inflated with air only; no liquid shall be used.
Ballasts to obtain the weight directed by the Engineer shall consist of bulk sand, bulk stone, bags of sand, stone, or other materials of known unit weight such that the total weight of the ballast used can be readily determined at all times. There shall be a sufficient amount of ballast available to load the equipment to a maximum gross weight of 50 tons. The loaded roller shall be so constructed or covered that it will not trap water which will add weight to the ballast.
Rubber tired or other types of tractive equipment may be used for operation of this equipment on the roadbed. The entire assembly including motivating equipment shall be capable of executing a 180 degree turn on a 27 foot wide area.
After the roadbed has been completed within 0.50 foot of final grade, the roadbed shall then be compacted and tested with 1 coverage, unless otherwise directed by the Engineer, of a heavy pneumatic tired roller meeting the requirements of Article 2602. A coverage is considered that stage in the rolling procedure when the entire width of the area being proof rolled has been in contact with the pneumatic tires of the roller. The roll shall be operated in a systematic manner so that the number of coverages over all areas to be proof rolled can be readily determined and recorded.
The equipment shall be operated at a speed between 225 and 300 feet per minute.
Proof rolling shall be done only in the presence of an inspector.
If it becomes necessary to take corrective action, such as but not limited to underdrain installation, undercut and backfill of an unsuitable material, and aeration of excessively wet material in areas that have been proof rolled, these areas shall be proof rolled again following the completion of the necessary corrections. If the corrections are necessary due to the negligence of the Contractor or weather, the corrective work and additional proof rolling shall be performed by the Contractor at no cost to the Department.
The Contractor shall protect all structural facilities on the project, such as but not limited to bridges, box culverts, pipe culverts, and utilities, from damage by the proof rolling equipment. Protection may include unloading and reloading of the roller, detouring, protective earth pads, or other suitable measure to avoid damage.
The quantity of proof rolling to be paid for will be the actual number of hours, measured to the nearest 0.1 hour, during which the heavy pneumatic tired roller has been engaged in proof rolling in the presence of an inspector exclusive of hours of proof rolling performed following corrective action made necessary by the negligence of the Contractor or by weather.
The number of hours of actual rolling time, measured as provided in Article 2604, will be paid for at the contract unit price per hour for "Proof Rolling".
Corrective work necessary, as determined by proof rolling, and not due to the negligence of the Contractor or to weather, will be paid for at the applicable contract unit prices or as extra work, whichever may be applicable.
The above prices and payments will be full compensation for all work covered by this section including but not limited to furnishing all labor, equipment, fuel, and ballast for loading; loading and unloading ballast as directed; and increasing and decreasing tire pressure as directed.
Payment will be made under:
Proof Rolling Hour