tamper shall weigh not less than fifty (50) pounds and have a face area of not more than one hundred (100) square inches.

206-3.7 APPLYING SCREENINGS. After the coarse aggregate has been thoroughly keyed and set by the rolling described, screenings in an amount that will completely fill the interstices shall be applied gradually over the surface. Dry rolling shall be continued while the screenings are being spread so that the jarring effect of the roller will cause them to settle into the voids of the coarse aggregate. The screenings shall not be dumped in piles on the coarse aggregate but shall be spread in thin layers.

The roller used shall meet the requirements specified above and be equipped with a broom of an approved type. The screenings shall be applied at a uniform and slow rate so as to insure filling of all voids. Hand brooms, where necessary, shall be used to sweep the screenings into unfilled voids and to distribute them. The spreading and rolling and brooming of screenings shall be performed on sections not to exceed 2,000 square yards, and shall continue until no more screenings can be forced into the voids of the coarse aggregate when the screenings are dry.

206-3.8 SPRINKLING. Immediately after the voids of a section of the course have been filled with screenings the macadam shall be sprinkled, the sprinkler being followed by the roller. All excess screenings forming in piles or cakes on the surface shall be scattered by light sweepings. The sprinkling and rolling shall continue and additional screenings applied where necessary until all voids are completely filled and the coarse stone firmly set and bonded. The quantity of screenings and water necessary, determined by the engineer, shall be sufficient to completely fill and bond the entire depth of the layer of the coarse aggregate and to produce a granular surface.

206-3.9 SURFACE TEST. After the course is complete the surface shall be tested for smoothness and accuracy of grade and crown, and if any portions are found to lack the required smoothness or to fail in accuracy of grade or crown such portions shall be scarified, reshaped, recompacted, and otherwise manipulated as the engineer may direct until the required smoothness and accuracy is obtained. The finished surface shall be such that it will not vary more than threeeighths (%) of an inch from the sixteen (16) foot straightedge applied to the surface parallel to the center line and at right angles.

206-3.10 RECONSTRUCTING MACADAM. Should the underlying course at any time become soft or churned up with the base course material or the shoulder material mixed with the base course material the contractor shall, without additional compensation, remove the mixture from the affected portion, reshape and compact the underlying course, and replace the removed section in accordance with the foregoing requirements.

206-3.11 THICKNESS. The thickness of the base course shall be determined by depth tests or cores taken at intervals in such manner that each test shall represent no more than 300 square yards. Where

the base deficiency is more than one-half (2) inch the contractor shall correct such areas by taking up the base material, removing and replacing with satisfactory materials properly laid, rolled, bonded, and finished in accordance with these specifications. The contractor shall replace, at his expense, the base material where borings are taken for test purposes.

206-3.12 MULTIPLE LAYERS. When it is necessary to construct the course in more than one layer to conform to the lines, grades, and cross sections indicated on the plans, each layer shall be constructed as described above.

The surface of the base course shall be maintained in its finished condition until any surface course or pavement provided in the contract is placed thereon, and the contract is completed.

206-3.13

PROTECTION. Work on the stone base shall not be prosecuted during freezing temperatures nor when the subgrade is wet. When the stone or screenings contain frozen materials or the underlying course is frozen the construction shall be stopped.

In general, hauling equipment may be routed over completed portions of the base course, provided no excessive damage results and provided that such equipment is routed over the full width of the base course to avoid rutting or uneven compaction. However, the engineer in charge shall have full and specific authority to stop all hauling over completed or partially completed base course when, in his opinion, such hauling is causing excessive damage. Any damage resulting to the base course from routing equipment over the base course shall be repaired by the contractor at his own expense.

During the placing, spreading, and rolling of the insulation course, coarse aggregate and screenings, care shall be exercised to prevent the incorporation of subgrade, subbase, or shoulder material into these macadam materials.

206-3.14 FREIGHT AND WEIGH BILLS. Before final estimate is allowed, the contractor shall file with the engineer receipted freight bills on all coarse aggregate and screenings as separate items where railroad shipments are made, and certified weigh bills when the material is received by any other manner, showing the actual tons that have been used in this item.

Copies of all freight bills and weigh bills shall be furnished the engineer during the progress of the work.

METHOD OF MEASUREMENT

206-4.1 The yardage of macadam base course to be paid for shall be the cubic yards of base course material including all screenings, bonded and accepted in the completed base course. Quantities of base course material and screenings shall be measured in final position based upon depth tests or cores taken as directed by the engineer, or at the rate of one depth test for each 300 square yards of base course, or by means of average end areas on the completed work computed from elevations to the nearest 0.01 foot.

The depth of the base shall not include the insulation course. On individual depth measurements, thicknesses more than one-half (2) inch in excess of that shown on the plans shall be considered as the specified thickness plus one-half (2) inch in computing the yardage for payment.

BASIS OF PAYMENT

206-5.1 The yardage of macadam base course measured as provided above shall be paid for at the contract unit price per cubic yard for macadam base course, which price and payment shall constitute full compensation for furnishing, hauling, and placing the materials; for spreading, sprinkling, and rolling; for reconditioning the underlying course and shoulders; for placing, watering, and rolling insulation course; for reconstruction of damaged or deficient base; for maintenance of surface; for refilling test holes; and for all labor, equipment, tools, water, and incidentals necessary to complete the work.

Payment will be made under:

Item P-206-5.1 Water Bound Macadam Base Course-per cubic

yard.

ITEM P-208 AGGREGATE BASE COURSE

DESCRIPTION

208-1.1 This item shall consist of a base course composed of crushed or uncrushed coarse aggregate, bonded with either soil or fine aggregate or both, constructed on a prepared underlying course in accordance with these specifications and in conformity with the dimensions and typical cross section shown on the plans and with the lines and grades established by the engineer.

MATERIALS

I. Uncrushed Coarse Aggregate: 208-2.1

MATERIALS. The base course material shall consist of hard, durable particles or fragments of stone or gravel mixed or blended with sand, clay, stone dust, or other similar binding or filler materials produced from approved sources to provide a uniform mixture complying with the requirements of these specifications as to gradation, soil constants, and capability of being compacted into a dense and well-bonded base. All oversize pebbles, stones, rock, and boulders occurring in the pit or quarry material shall be screened out or removed and wasted; those of acceptable quality may be crushed and become a part of the base material, provided the blend meets the specified gradations. The aggregate shall be free from vegetable matter, loam, lumps or excessive amounts of clay and other objectionable or foreign substances. The coarse aggregate shall have a percent of wear of not more than 50 at 500 revolutions as determined by A. A. S. H. O. Method T-96 (Los Angeles Rattler Test).

II. Crushed Coarse Aggregate:

208-2.2 MATERIALS. The aggregates shall consist of both fine and coarse fragments of crushed stone, crushed slag, or crushed gravel, blended if required, with soil, sand, screenings, or other similar approved materials. The completed mixture of aggregates shall be capable of being compacted into a dense and well-bonded base.

The crushed stone shall consist of hard, durable particles or fragments of stone, free from an excess of flat, elongated, soft or disintegrated pieces, dirt, or other objectionable matter, and shall have a percent of wear of not more than 50 at 500 revolutions as determined by A. A. S. H. O. Method T-96 (Los Angeles Rattler Test).

The crushed slag shall be air-cooled blast furnace slag and shall consist of angular fragments, reasonably uniform in density and

quality, and reasonably free from thin, elongated, or soft pieces, dirt, and other objectionable matter. It shall weigh not less than seventy (70) pounds per cubic foot and shall have a percent of wear of not more than 50 at 500 revolutions as determined by A. A. S. H. O. Method T-96 (Los Angeles Rattler Test).

The crushed gravel shall consist of hard, durable stones, rock, and boulders of accepted quality crushed to specified size, and shall be free from an excess of flat, elongated, soft or disintegrated pieces, dirt, or other objectionable matter. The method used in production of crushed gravel shall be such that the percentage of fractured particles occurring in the finished product shall be as nearly constant and uniform as practicable. The crushing of the gravel shall result in a product that at least sixty (60) percent of the material passing a 2-inch sieve and retained on a 1-inch sieve; that at least sixty (60) percent of the material passing a 1-inch sieve and retained on a 34-inch sieve, and that at least sixty (60) percent of the material passing a 4-inch sieve and retained on a No. 4 mesh sieve will have at least one fractured face. If necessary to meet this requirement or to eliminate an excess of fine, uncrushed particles the gravel shall be screened before crushing. All stones, rocks, and boulders of inferior quality occurring in the pit shall be separated out and wasted. The gravel shall have a percent of wear of not more than 50 at 500 revolutions as determined by A. A. S. H. O. Method T-96 (Los Angeles Rattler Test).

All material passing the No. 4 mesh sieve produced in the crushing operation of either the stone, slag, or gravel shall be incorporated in the base material unless there is an excessive amount which, if included, would not meet the gradation requirements.

III. Requirements Applying to I and II:

208-2.3 GRADATION. The gradation of the processed or unprocessed material shall meet the requirements of one of the gradations given in the table below using A. A. S. H. O. Methods T-11 and T-27.