304Aggregate Base Course

Aggregate Base Course

Description

304.01This work consists of furnishing and placing one or more courses of aggregate and

additives, if required, on a prepared subgrade.

Materials

304.02Aggregate. The aggregates shall meet the requirements of subsection 703.03

Acceptance will be based on random samples taken from each lift.

304.03Commercial Mineral Fillers. Portland cement shall conform to subsection 701.01

Hydrated lime shall conform to subsection 712.03.

Construction Requirements

304.04Placing. If the required compacted depth of the aggregate base course exceeds 6

inches, it shall be constructed in two or more layers of approximately equal thickness. The maximum compacted thickness of any one layer shall not exceed 6 inches. When vibratory or other approved types of special compacting equipment are used, the compacted depth of a single layer may be increased to 8 inches upon request, provided that specified density is achieved, and written approval is given.

304.05Mixing. The Contractor shall mix the aggregate by methods that ensure a thorough and

homogenous mixture.

304.06Shaping and Compaction. Compaction of each layer shall continue until a density of at

least 95 percent of the maximum density has been achieved as determined per AASHTO T 180 as modified by CP 23. The moisture content shall be at plus or minus 2 percent of optimum moisture content. The surface of each layer shall be maintained during the compaction operations so that a uniform texture is produced, and the aggregates are firmly keyed. Moisture conditioning shall be performed uniformly during compaction.

Compaction of each reclaimed asphalt pavement aggregate layer shall continue until a wet density of at least 95 percent of the maximum wet density when determined per a one-point AASHTO T 180, Method D test has been achieved. The surface of the base course will be tested with a 10-foot straightedge, or other approved device. The surface shall be tested before the application of any primer or pavement. The variation of the surface from the testing edge of the straightedge between any two contacts with the surface shall not exceed 1/2 inch. All irregularities exceeding the specified tolerance shall be corrected to the satisfaction of the Engineer at no additional cost to the Department.

The above compaction and straightedge requirements shall not apply to shoulder gravel. Compaction of shoulder gravel shall be accomplished by wheel rolling, as directed.

304.07

Method of Measurement

304.07Aggregate base course will be measured by the ton, or by the cubic yard compacted

in place.

Basis of Payment

304.08The accepted quantities of aggregate base course, of the class specified, will be

paid for at the contract price bid per ton or per cubic yard, as shown in the bid schedule.

Payment will be made under: Pay Item Pay Unit Aggregate Base Course (Class ) Ton, Cubic Yard Aggregate Base Course (RAP) Ton, Cubic Yard

Water will not be measured and paid for separately but shall be included in the work. Commercial mineral fillers, when used, will be measured and paid for per Section 307 or as provided in the Contract.

306.01