00641.12 693 Section 00641 - Aggregate Subbase, Base, and Shoulders
Description
00641.00Scope - This Work consists of furnishing and placing one or more layers of Aggregates,
mixed with water, on a prepared surface to the lines, grades, thicknesses and Cross Sections shown or established.
Materials
00641.10Materials:
specified. Bas e Aggregate shall be dense-graded unless otherwise specified. Shoulder Aggregates shall be either 1" - 0 or 3/4" - 0 size as the Contractor elects.
Furnish Base and Shoulder Aggregates meeting the following requirements:
Dense-Graded Base Aggregate ............................................................ 02630.10 Open-Graded Aggregate ....................................................................... 02630.11
Sands, reasonably well graded from coarse to fine. Maximum size Aggregate shall not exceed 75 percent of the compacted thickness of the layer in which it is incorporated. Aggregates passing the 1/4 inch sieve shall not be less than 10 percent nor more than 50 percent of the whole, by weight. No more than 10 percent of the Aggregate shall pass the No. 100 sieve. Within these limits, the Subbase Aggregate gradation shall be adequate to produce a dense, firm Base when placed and compacted.
gradation will be determined by sieve analysis according to AASHTO T 27.
when tested according to AASHTO T 96 unless otherwise approved.
have a Sand equivalent of not less than 25.
00641.11Stockpiling - If the produced Aggregates are to be stockpiled, prepare the stockpile site
and pile the materials according to 00680.40 and 00680.41.
00641.12Limits of Mixture - Provide a mixture of Aggregate and water having a uniform moisture
content sufficient to obtain the required compaction. Proportions will be in percentages by weight and will be known as the Mix Desi gn. Determine t he proportion of Aggregate and water according to
When introducing water at the mixing plant, furnish the mixture with a tolerance of ± 2 percent of the optimum water content at the time of mixing. If approved, excess percentage of water may be allowed. The Agency will treat excess percentage of water a ccording to 00641.80(d).
00641.15 694 00641.15 Quality Control :
Aggregates. Statistically evaluate the Aggregates.
issuance of Notice to Proceed will be determined according to (1) or (2) below.
00641.16Acceptance of Aggregates - Acceptance will be accor ding to Section 00165
the Contractor's quality control testing, if verified, as required in Section 00165.
Quality Level (QL) for each sieve size, calculated according to 00165.40, is equal to or greater than the QL in Table 00165-2 for a PF of 1.00. Each required sample represents a sublot. When the QL in Table 00165-2 yields a PF of less than 1.00 for any sieve size, the material is non-specification.
Aggregate gradation will be rejected unless the non-specification material is removed from the stockpile. Do not add additional material to the stockpile until enough non- specification material has been removed so that the QL for each sieve size is equal to or gre ater than the QL in Table 00165-2 for a 1.00 PF.
No payment will be made for non -specification materials.
samples obtained immediately following mixing with water according to Section 00165. For non-specification mixture the Engineer will determine the appropriate price reduction or order its removal from the Work according to 00150.25.
inspection. Samples will be obtained and tested for compliance with 00641.10 by the Engineer if it is suspected that the material does not meet Specifications.
Equipment
00641.20Mixing Plant - Mix Aggr egate and water by one of the following methods:
• Has adjustable weighing or calibrated feeders, and other Equipment that produces uniform, non-segregated, specified mixtures. • Discharges water into the mixer by weighing or metering. The device shall be adjustable and shall assure uniform water content in the mixture. • Has mixing blades or paddles of proper size, adjustment and clearance to provide uniform mixture.
00641.43 695
00641.21Hauling Equipment - Provide mixture hauling vehicles capable of hauling and depositing
the mixture with a minimum of mix segregatio n.
00641.22Spreading Equipment - Provide Equipment capable of spreading the M aterial and striking
it off to designated line, grade, and transverse Slope without segregation, dragging, or fracture of Aggregate.
00641.24Compacting Equipment - Provide self -propelled rollers and compactors capable of
reversing without backlash. Rollers and compactors shall have a gross static weight of at least 8 Tons, and shall be capable of compacting to specified density while the mix is still moist.
Labo r
00641.30Quality Control Personnel - Provide technicians having CEBT, CAgT, and CDT technical
certifications. Construction
00641.40Preparation of Foundation - Provide a firm surface or material, on which Aggregates are
to be placed, according to Sections 00320, 00330, or 00610 as applicable.
00641.41Mixing, Hauling, and Placing - Add water to the Aggregate while mixing to provide a
moisture content according to 00641.12.
Thoroughly mix the combined Aggregate and water for as long as necessary to produce a homogenous mixture with all Aggregate particles uniformly coated with water. Mix, haul and place the Material by one of the following methods:
Deliver and deposit the mixture without delay. Deliver the mixture to the spreading Equipment by direct deposit into its receiving device, or by placing in uniform windrows in front of the Equipment .
homogeneous mixture is achieved.
Do not place Aggregate shoulder material on the top Lift of newly constructed EAC or open- graded Pavement .
00641.42Placing Aggregate Base or Subbase on Geotextile - When Subgrade or drainage
geotextile is required between the Subgrade and Base , place the first Lift of Material directly on the fabric, without road mixing.
00641.43Thickness and Number of Layers:
6 inches, construct it in two or more layers of nearly equal thickness. The maximum compacted thickness of any one layer shall not exceed 6 inches unless approved.
Place each layer in spreads as wide as practicable and to the full width of the Course before a succeeding layer is placed.
exceed 9 inches unless approved.
00641.44 696 (c) Shoulder Courses - Place Aggregates in Shoulder areas, other than as part of the Base Course, in one layer, or in two or more layers of nearly equal thickness. The maximum compacted thickness of any one layer shall not exceed 9 inches.
00641.44Shaping and Compacting :
immediately after the M aterial is spread and continue until a density of not less than 95 percent of the maximum density has been achieved.
using rollers conforming to 00641.24. Roll until there is no appreciable reaction or yielding under the compactor. Shape and maintain the surface of each Aggregate layer during the compaction operations to produce a finished surface meeting the requirements of 00641.45.
Apply additional water over the M aterials for proper compaction, according to Section 00340 and as directed.
and Shoulder Material until no reaction or yielding is observed under the compactor.
00641.45Surface Tolerance - The finished surface of the Aggregate and the surface of each
underlying layer shall parallel the established grade and Cross Section for the finished surface within 0.04 foot. The finished surface of the compacted Aggregate, wh en tested with a 12- foot straightedge, shall not vary from the testing edge by more than 1/2 inch at any point. Furnish and operate the straightedge as directed.
Maintenance
00641.60Care of the Work - After construction of each layer and completion o f Base , maintain the
layer to specified conditions and prevent or repair segregation, raveling, or rutting until it is covered with a following layer or until all Work is completed.
Measurement
00641.80Measurement - The quantities of Aggregate mixture will be measured on the weight basis,
on the volume basis, or on the area basis according to the following:
vehicle, after mixing.
vehicle.
of Aggregate Base constructed to the full thickness. The surface area will be determined by horizontal measurements. Each area constructed with varying thicknesses, as directed or shown, will be adjusted by converting it to an equivalent area at the Pay Item thickness on a proportionate volume basis. 00641.91 697
to 00641.41(a) exceeds the percentage established in the mix design by more than 2 percent, the excess percentage of water will be deducted from the measurement of the mixture. Determination of excess water will be made by the same procedure used in setting the water content of the Mix Design under 00641.12 or converted to the equivalent volume.
If Aggregates are stationary plant mixed, no separate measurement will be made for water added at the plant to bring the material to optimum moisture content.
If Aggregates are road mixed, water used to bring the mixture to optimum moisture content will be measured according to 00340.80.
Payment
00641.90Payment - The accepted quantities of Aggregates will be paid for at the Contract unit price,
per unit of measurement, for the following items:
Pay Item Unit of Measurement
Items (b) and (d) will apply when the Contractor has the option of furnishing one or another of two or more designated sizes of Aggregates.
In items (c) and (e), the designated size of Aggregate to be used will be inserted in the blank.
In item (g), the depth of Aggregate Base will be inserted in the blank. Payment will be payment in full for furnishing and placing all Materials, and for furnishing all Equipment , labor, and Incidentals necessary to complete the Work as specified.
No separate or additional payment will be made for water used in the mixture, mixed and placed according to 00641.41(a), subject to the limitations of 00641.80(d).
No separate or additional payment will be made for water used in the care of the Work according to 00641.60.
00641.91Material on Hand - Payment for stockpiled materials on hand may be allowed according
to 00195.60, subject to the requirements of 00641.10, 00641.15, 00641.16(a), and subject to QA verification.