Attachment B.pdf

208.1 208.4.1

SECTION 208

SUBGRADE

208.1

208.1 Description

208.1 This section contains specifications for the materials, equipment, construc-tion, measurement, and payment for the construction and preparation of the subgrade intended to receive the pavement structure, sidewalk, curb, curb and gutter, and shoulders.

208.2

208.2 Materials

208.2 None specified.

208.3

208.3 Equipment

208.3 Ensure that the equipment necessary for the proper construction of the work is on site, in acceptable working condition, and approved by the RCE as to both type and condition before the start of work under this section. Provide sufficient equipment to enable prosecution of the work in accordance with the project schedule and completion of the work in the specified time.

208.4

208.4 Construction

208.4.1

208.4.1 General

208.4.1 Remove all soft, unstable, or unsuitable material that does not compact readily. Replace this material with satisfactory material as directed by the RCE. Remove or break off all objectionable loose rock or boulders to a depth of not less than 6 inches below the surface of the subgrade. Fill all holes, ruts, or depressions that develop in the subgrade with approved material, bring the subgrade to line and grade, and properly compact. Perform this work without any additional compensation. If the subgrade is too dry to com-pact properly, sprinkle with water to wet it, if deemed desirable by the RCE, to secure proper compaction.

208.4.1 Compact the subgrade between lines 18 inches outside the area occupied by the pavement structure, including curb and gutter and sidewalk as applica-ble, to not less than 95.0% of maximum density. Accomplish the compaction by using suitable construction procedures while the subgrade is at suitable moisture content. Maximum densities are determined by either SC-T-25 (Method A or C as applicable) or SC-T-29.

208.4.1 On projects where the base and pavement are constructed under a later contract, compact the subgrade as specified above to not less than 95.0% density.

208.4.1 When any portion of the subgrade is constructed on an old roadbed that conforms to or approximates the elevation of the subgrade, scarify and grade the existing surface as directed by the RCE so that the subgrade has a uni-form density when compacted.

208.4.2 208.6

208.4.2

208.4.2 Protection and Maintenance

208.4.2 Maintain the subgrade in a smooth and fully compacted condition, free from ruts and depressions, and adequately drained. Storing or stockpiling of mate-rials directly on the subgrade is not permitted without the prior approval of the

RCE.

208.4.2 Never, under any circumstances, place any base, surface course, or pave-ment before the subgrade is checked and approved by the RCE.

208.4.2 Never, under any circumstances, place any base, surface course, or pave-ment on frozen, muddy, or unstable subgrade.

208.4.3

208.4.3 Fine Grading

208.4.3 After all earthwork is substantially complete and all drains and structures completed and backfilled and the subgrade compacted to the satisfaction of the DCE, make certain that the subgrade conforms to the lines, grades and cross-sections shown on the Plans or as established by the RCE.

208.4.3 Ordinarily the costs necessary to complete fine grading of the subgrade are included in other items of work. Typically, these costs are included in excava-tion items or other items that may be subject to increases or decreases from the plan quantities as field conditions dictate. In order to alleviate this issue, an item, Fine Grading, has been established and may be included in the Con-tract at the discretion of the Department.

208.4.3 Fine Grading is defined as the work necessary to bring the in-place earth material into the final shape and compacted condition prescribed in the Con-tract documents. The area considered for Fine Grading is the area described in Subsection 208.4.1, which extends laterally 18 inches beyond the pave-ment structure.

208.5

208.5 Measurement

208.5 The quantity for the pay item Fine Grading is the surface area of the sub-grade that is constructed and prepared for the intended pavement structure, sidewalk, and shoulders and is measured by the square yard (SY), complete, and accepted.

208.5 If the pay item Fine Grading is not included in the Contract, the grading work is not measured for payment directly and is considered included in con-tract unit bid price of the various other items of work.

208.6

208.6 Payment

208.6 Payment for the accepted quantity for Fine Grading, measured in accor-dance with Subsection 208.5, is determined using the contract unit bid price for the pay item. Payment is full compensation for grading and forming the subgrade as specified or directed and includes all materials, labor, equipment, tools, supplies, transportation, and incidentals necessary to complete the work in accordance with the Plans, the Specifications, and other terms of the Contract.

208.6 208.6

208.6 Payment for this item includes all direct and indirect costs and expenses necessary to complete the work.

208.6 Pay items under this section include the following:

208.6

Item No. Pay Item Unit

2081001 Fine Grading SY

401.4.14 401.4.17

401.4.14

401.4.14 Removal of Existing Asphalt Pavement before Patching

401.4.14 Remove the deteriorated pavement to the width and length as determined by the RCE, with the face of the cut being straight and vertical. Construct patches with a minimum patch size of 6 feet X 6 feet with at least 25 feet be-tween patches. Remove the pavement to the depth indicated in the Plans. If unstable material is encountered at this point, remove additional material as directed by the RCE. Backfill the volume of material removed below the patch with material meeting the requirements of Section 305, Graded Aggregate Base and thoroughly compact in layers not exceeding 4 inches with vibratory compactors. Thoroughly tack the sides of the existing asphalt pavement be-fore placing the asphalt patch material in the hole. Place the patch material in layers not exceeding 3 inches. Thoroughly compact each layer with a vibra-tory compactor and pneumatic roller. Conduct the work so that patches are opened and filled the same day, with the roadway being opened to traffic by late that same day. Ensure that the finished patch is smooth riding. Do not apply asphalt mixture when the existing surface is wet or frozen.

401.4.15

401.4.15 Conditioning of Subgrade

401.4.15 Before placing any HMA base course mixture, prepare the subgrade in ac-cordance with the requirements specified in Section 208.

401.4.16

401.4.16 Surface Preparation and Leveling

401.4.16 Prepare base courses as specified in the applicable sections of Division 300.

401.4.16 Thoroughly sweep the base course, old pavement, or existing surface so that it is clean and free from dust and foreign material. Maintain it until the HMA is placed.

401.4.16 Bring irregularities in the surface of the existing pavement or old base (in-cluding widened shoulders where settled) to uniform contour by leveling with HMA. Place the leveling HMA in a separate operation from the specified depth of surface course. Thoroughly compact the leveling HMA until it con-forms to the surrounding surface. Where necessary, perform the leveling with a motor grader or paver.

401.4.17

401.4.17 Transportation and Delivery of Mixes

401.4.17 Transport the HMA from the plant to the point of use in vehicles meeting the requirements of Subsection 401.3.7. Do not permit any load of HMA to leave the plant so late in the day that it cannot be spread, finished, and com-pacted during daylight of that same day unless an approved artificial lighting system is provided.

401.4.17 Deliver the HMA to the spreader at a temperature within 20ºF of the tem-perature set at the plant.