PART 2 SECTION 3. SUBGRADE BASE CONSTRUCTION

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1 3-1 Subgrade PART 2 SECTION 3. SUBGRADE BASE CONSTRUCTION General - The work specified in this section includes the preparation of the ground on which the sub-base, base, pavement or other surfacing materials is to be placed, as specified. The finished sub-grade plane lies between the sub-grade and the lowest element of any other surfacing material placed on it. All relative compaction shall be not less than 95 percent, for a depth of 0.5 ft. regardless of location. All subsequent material placed thereon shall have a relative compaction of 95 percent throughout unless otherwise specified herein. The top six inches of sub-grade material and all subsequent material under gutter, driveways, sidewalks and curbs shall be compacted to a relative compaction of at least 95 percent unless otherwise specified. All work and materials are to be in conformance with applicable portions of Sections 25 and 26 of the State Specifications except as modified herein. After compaction and trimming, the sub-grade shall be firm, hard, and unyielding. Unsuitable sub-grade material as determined by the Engineer shall be removed to a depth specified by the Engineer and disposed of as directed by the Engineer. Soft material as determined by the Engineer may be allowed to dry and be reprocessed at no cost to the City. Any removed material shall be replaced with suitable material approved by the Engineer and shall be compacted to a relative compaction of not less than 95 percent. Any such work, including the removal, disposal, and replacement of said material, shall be paid for as extra work less the cost of processing the top six inches unless otherwise specified. Applied water when directed by the Engineer, in connection with subgrade preparation, will not be measured and paid for separately. The Contractor shall repair at his expense any damage to prepared subgrade caused by his operation or by use of public traffic. No material shall be placed upon the prepared sub-grade until the sub-grade is in the condition meeting the requirements specified. In order to facilitate the preparation of sub-grade, the Contractor may, if be elects, remove rocks, lumps, and break up hardened material or temporarily construct a rough grading plane below the sub-grade elevation, provided he.subsequently brings such rough grading plane up to sub-grade elevation with

2 suitable material approved by the Engineer and that said material is compacted to a relative compaction of not less than 95 percent. Any such work shall be at the expense of the Contractor and no separate payment will be made therefore Sub-grade Tolerance Sub-grade for asphalt concrete, concrete, or other road-way structures shall not vary more than 0.03 ft. from the specified grade and cross-section. Variations within the specified tolerances shall be compensated so that the average grade and cross-section specified are met. 3-l.3 Payment - No separate measurement or payment will be made for preparing sub-grade, and full compensation for furnishing all labor, materials, tools, equipment, and incidentals, and for doing ail the work involved in preparing sub-grade as specified, shall be included in the contract price paid for the various contract items of work. No additional payment shall be made. 3-2 Aggregate Sub-base General - The work specified in this section includes furnishing, spreading, and compacting mineral aggregate sub-base and aggregate base in accordance with these specifications Aggregate Sub-base A. General - Aggregate sub-base shall be mineral aggregate conforming to Section 25 of the State Standard Specifications for Class 2 Aggregate Subbase and as modified here in. B. Materials - Mineral aggregate for the aggregate sub-bases, at the time it is deposited, shall conform to the following requirements: C. Quality - Aggregate for aggregate sub-base shall be clean and free from vegetable matter and other deleterious substances and shall be of such quality that it will bind readily to form a firm, stable sub-base. D. Gradation - The percentage composition by weight of aggregate sub-base shall conform to the following grading when determined by Test Method No. Calif (from Section A of the State Standards for Class 2 moving average).

3 Sieve Sizes Percentage Passing Seive 3" I00 2 I/ I00 # # # E. Recycled Aggregate Sub-Base - Existing uncontaminated asphalt concrete and aggregate base, where practicable, may be removed and recycled as aggregate sub-base. The existing asphalt concrete and aggregate base shall be broken up to size conforming to Section 3-2.2, "Aggregate Sub-base," of these Specifications as hereinafter modified. Recycled materials shall be mixed to a uniform gradation prior to spreading and compaction. Recycled aggregate base shall be measured for payment by the cubic yard based on theoretical cross-section measured in place and payment shall be made therefore in conformance with the contract price paid for the bid item aggregate sub-base. When the sub-base is placed in layers of three (3) inches thickness or less, the maximum size of aggregate shall be one (I) inch less than the compacted thickness of the layer of sub-base in which it is placed Tests - The aggregate sub-base shall conform to the following tests: Test Method No. Calif. Requirements Resistance (R-Value) minimum Sand Equivalent Minimum The R-Value requirements may be waived provided that the aggregate sub-base conforms to the specified grading and has a sand equivalent value of 25 or more. 3-3 Aggregate Base General - Aggregate base shall consist of a crushed material aggregate forming, conforming to Section 26 of the State Standard Specifications for Class 2, Aggregate Base, as modified herein.

4 3-3.2 Materials A. Quality - Aggregate furnished for the base shall be free from Vegetable matter and other deleterious substances, and shall be of such nature that it can be compacted readily under watering and rolling to form a firm stable base. Aggregate may be delivered with water added. The Coarse Aggregate (material retained on the No. 4 sieve) shall consist of material of which at least 25 percent, by weight, shall be crushed particles as determined by the Test Method No. Calif B. Gradation - The percentage composition by weight of aggregate base shall conform to the following grading when determined by Test Method No. Calif. 202, modified by Test Method No. Calif. 905 where there is a difference in specific gravity of 0.2 or more between the coarse and fine portion of the aggregate or between blends of different aggregates. (From Section B of the State Specification for Class 2 Aggregate Base). I -I/2" Maximum 3/4," Maximum Percentage Percentage Sieve Size Passing Sieve Passing Sieve 2" 00 I -I/2" I" ¾ #/ # # Tests - The aggregate base shall conform to the following tests: Requirements Test Method No. Calif. 3-4 Preparation Resistance (R-Value) Minimum Sand Equivalent Minimum Sub-base and Base Preparation - Aggregates for sub-base and base shall be delivered to the roadbed as uniform mixtures and shall be spread in layers or windrows. Segregation of aggregates shall be avoided and material as speed shall be free from pockets of large or fine material. Segregated materials shall be remixed until uniform.

5 Where the required thickness is 0.5 foot or less, the aggregate sub-base or base may be spread and compacted in one layer. Where the required thickness is more than 0.5 foot, the sub-base or base aggregate shall be spread and compacted in two or more layers of approximately equal thickness. The maximum compacted thickness of any one layer shall not exceed 0.5 foot. Each layer shall be spread and compacted in a similar manner. At locations where the aggregate sub-base or base is to be placed over areas inaccessible to the spreading equipment, the aggregate sub-base or base may be spread and compacted by any means to obtain the specified results Compacting and Tolerance - The relative compaction of each layer of compacted aggregate sub-base or base shall not be less than 95 percent as determined by Test Method No. Calif. 216 or 231. The finished surface of the aggregate base shall not vary more than 0.05 foot from the specified grade and cross section. Variations within the above specified tolerances shall be compensating so that the average grade and cross sections specified are met Measurement - Quantities of aggregate sub-base or aggregate base will be measured by the tan or cubic yard. If measured by the ton, water content in excess of optimum moisture content shall be deducted from the total weight of aggregate. If measured by the cubic yard, quantities of aggregates will be calculated on the basis of dimensions shown on the plans adjusted by the amount of change that may be ordered by the Engineer. No allowance will be made for aggregate rejected or placed outside said dimensions unless otherwise ordered by the Engineer. Payment will be at the price bid which price and payment includes full compensation for furnishing all labor materials, tools, equipment and incidentals and installing the items, complete as specified, including sub-grade preparation, reprocessing, watering, dust palliative, leveling, compacting and any and all costs to complete the item. 3-5 Treated Sub-grade or Bases General - Cement or lime treatment, if required, shall be in conformance with the applicable provisions of Section 20, or 27 of the State Specifications. The type, class, grade and amount of treatment shall be as specified or directed by the Engineer Measurement and Payment - Measurement shall be the square yard of treated surface meeting requirements specified and directed. Payment shall be at the unit price bid which includes all materials, equipment, labor and costs to perform the work except costs in other items. In the event there is no bid item for such treatment, it shall be measured and paid for as extra work according to provisions of approved change order.