310Graded Aggregate Construction

310.1General Description

This work includes constructing a base, subbase or shoulder course composed of mineral aggregates. Construct according to these specifications and to the lines, grades, thickness, and typical cross-sections shown on the plans or established by the Engineer. The provisions of Section 300 apply to this work. 310.1.01 Definitions General Provisions 101 through 150. 310.1.02 Related References

AASHTO T 180 GDT 21 GDT 59 310.1.03 Submittals General Provisions 101 through 150.

310.2Materials

Ensure that materials meet the requirements of the following Specifications: Material Section Graded aggregate 815 Cutback asphalt, RC-30, RC-70, RC-250 or MC-30, MC-70, MC-250 821.2.01 Cutback Asphalt Emulsion, CBAE-2 823.2.01 Blotter material (sand) 412.3.05.G.3 310.2.01 Delivery, Storage, and Handling General Provisions 101 through 150.

310.3Construction Requirements

310.3.01 Personnel General Provisions 101 through 150. 326 326 326 326 326 326 326 326 326

310.3.02 Equipment Provide equipment in satisfactory condition for proper construction of the base, subbase or shoulder course. Use any applicable equipment specified in Subsection 412.3.02, Equipment for Bituminous Prime. 310.3.03 Preparation Prepare the subgrade or subbase as specified in Subsection 300.3.03.C, Preparing the Subgrade or Subsection 300.3.03.D, Preparing the Subbase. Place graded aggregate materials only on dry, thawed subgrade or subbase. 310.3.04 Fabrication General Provisions 101 through 150. 310.3.05 Construction

Use the central plant mix method unless producing aggregates (from an approved source or deposit) that conform to the requirements of Section 815. Use the following steps to mix base and spread subbase or shoulder course.

When blending two sizes of aggregate, proportion the aggregate and water, if needed, into the central plant. Mix until producing a homogeneous and uniform mixture.

To obtain the specified thickness, uniformly spread materials to the proper depth with a mixture spreader. Do not use materials containing frost or frozen particles.

Lay one course to a maximum thickness of 8 in. (200 mm) compacted.

If the thickness of the base, subbase or shoulder course exceeds 8 in. (200 mm), construct it in 2 or more courses of equal thickness.

Use the following steps to compact and finish a base, subbase, or shoulder course.

Ensure that the moisture content of materials is uniformly distributed and allows compaction to the specified density. Unless approved by the Office of Materials and Research, no graded aggregate will be shipped to a project when the moisture content of the material exceeds two percent of optimum moisture.

After shaping the spread material to line, grade, and cross-section, roll to uniformly compact the course. If using Group 1 aggregate, roll to at least 98 percent of maximum dry density. If using Group 2 aggregate, roll to at least 100 percent of the maximum dry density. If using graded aggregate mixtures composed of either group as base for paved shoulders 6 ft. (1.8 m) wide or less, compact to at least 96 percent of the maximum dry density. Regardless of compaction, ensure that the compacted base is sufficiently stable to support construction equipment without pumping. If the base material is unstable from too much moisture, dry and rework the base material. Dry and rework the underlying subgrade, if necessary.

1) After compaction, shape to the required grade, line, and cross- section. 2) Add water as necessary to develop the proper moisture content. 3) Roll until the surface is smooth, closely knit, and free of cracks. 4) Correct all defects according to Subsection 300.3.06.B, Repairing Defects. 327 327 327 327 327 327 327 327 327

1) After compacting the first course, shape the surface again to line, grade, and cross section. 2) Add water as necessary to develop the proper moisture content. 3) Spread and compact the second and any succeeding courses without rolling the first course again. 4) Finish the surface according to the procedure specified for one-course construction.

In places inaccessible to the roller, obtain the required compaction with mechanical tampers approved by the Engineer. Apply the same density requirements as stated above in Subsection 310.3.05.B.

Finish the surface of the subbase for Portland cement concrete pavement or the base of asphaltic concrete pavement with automatically controlled screed equipment when required by Subsection 300.3.02.H, Fine Grading Machine of the specifications. Furnish, install, and maintain the sensing wires needed to control the finish operation as a part of the Pay Item. When automatically controlled screed equipment is not required, fine grading with motor graders is permitted. Finish immediately after the placing and compacting operations. After finishing, compact the subbase again, according to Subsection 310.3.05.B, Compacting Material.

Maintain the course until the Engineer determines that it has cured sufficiently and is ready to prime. Maintain by additional wetting, rolling, and blading as necessary. Repair any defects according to Subsection 300.3.06.B, Repairing Defects. These protection measures do not relieve the Contractor of maintaining the Work until final acceptance as specified in Section 105.

Apply bituminous prime according to Section 412 unless using: • Graded aggregate base under Portland cement concrete pavement • Graded aggregate base under asphaltic concrete 5 in. (125 mm) or more in total thickness 310.3.06 Quality Acceptance

AASHTO T180, Method D.

328 328 328 328 328 328 328 328 328

Check the finished surface of the base, subbase, or shoulder course as follows:

• A template, cut true to the required cross-section and set with a spirit level on non-super elevated sections • A system of ordinates, measured from a string line • A surveyor’s level

do not exceed 1/4 in. (6 mm) at any point. Rod readings shall not deviate more than 0.02 ft. (6 mm) from required readings.

Repairing Defects.

where the shoulders will be surfaced.

necessary to determine the average thickness.

determine the deficient area.

of the following methods according to these specifications: • Add additional quantities of the same materials and reconstruct to the required thickness • Leave in place and accept payment for the materials and area at ½ the Contract Unit Price for the deficient area.

same material and reconstructing to the required thickness in accordance with these Specifications.

will be made at the Contract Unit Price with no additional cost to the Department for scarification, mixing or compaction.

to correct deficiencies or for reconstructing deficient work.

increment exceeds the allowable 1/2 in. (13 mm) tolerance, the excess quantity in that increment will be deducted from the Contractor’s payments.

(13 mm) tolerance by the surface area of the base, subbase, or shoulder.

329 329 329 329 329 329 329 329 329

310.3.07 Contractor Warranty and Maintenance General Provisions 101 through 150.

310.4Measurement

Where specified for payment by the ton (megagram), graded aggregate base, subbase or shoulder materials are measured in tons (megagrams), mixed and accepted. When hauling material to the roadway, the actual weight of each loaded vehicle is determined with an approved motor truck scale. Where specified for payment by the square yard (meter) for a certain thickness, the surface length is measured along the centerline, and the width is specified on the plans. Measure irregular areas, such as turnouts and intersections, by the square yard (meter).

Bituminous prime is not measured for separate payment. 310.4.01 Limits General Provisions 101 through 150.

310.5Payment

Graded aggregate base, subbase, or shoulder course will be paid for at the Contract Unit Price per ton

compensation for: • Materials • Shaping and compacting the existing roadbed • Loading, hauling, and unloading • Crushing and processing • Mixing • Spreading • Watering • Compacting and shaping • Maintenance • Priming, when required • All incidentals necessary to complete the work 330 330 330 330 330 330 330 330 330

If used in lieu of graded aggregate, the pay tons for graded aggregate with Recycled Concrete Aggregate calculated in accordance with Subsection 310.4.C will be paid for at the graded aggregate contract unit price. This pay shall be full compensation for: • Materials • Shaping and compacting the existing roadbed • Loading, hauling, and unloading • Crushing and processing • Mixing • Spreading • Watering • Compacting and shaping • Maintenance • Priming, when required • All incidentals necessary to complete the work

Payment will be made under:

Item No. 310 Graded aggregate (base, subbase, shoulder course)—including

material

Per ton (megagram) or square

yard (meter)

Item No. 310 Graded aggregate with Recycled Concrete Aggregqate (base,

subbase, shoulder course)—including material

Per ton (megagram)

Item No. 310 Graded aggregate base and shoulder course— including material Per ton (megagram) or square

yard (meter)

Item No. 310 Graded aggregate base and shoulder course with Recycled

Concrete Aggregate— including material

Per ton (megagram)

310.5.01 Adjustments

General Provisions 101 through 150.. 331 331 331 331 331 331 331 331 331