the underlying course or contaminating the mixture with earth or othe extraneous matter. When directed, the mixing process shall be con fined to part of the width or area of the road so as to allow traffic t pass.

Should the mixture show an excess, deficiency or uneven distribution of bituminous material, the condition shall be corrected by the addition of aggregate or bituminous material as required and re-mixing. If the mixture contains excessive amounts of moisture or volatile matter, it shall be bladed, aerated or otherwise manipulated until the moisture and volatile content are satisfactory. The spreading of the mix shall not be done when the surface to be covered is in an unsatisfactory condition.

At the end of each day's work, or when the work is interrupted by weather conditions or otherwise, all loose material shall be bladed into a windrow, whether mixing is completed or not, and shall be retained in a windrow until operations are resumed.

When the mixing operations have been satisfactorily completed, the mixture shall be formed into a windrow of uniform cross section.

If the Contractor elects to use traveling or stationary mixing plants in lieu of the specified equipment, the same requirements regarding residual moisture and evaporation of volatiles given above shall apply. 405.10 Spreading, Compacting, and Finishing. The material shall be spread by a self-propelled, pneumatic-tire blade grader or a mechanical spreader of approved type. In spreading from the windrow, care shall be taken to avoid cutting into the underlying base.

After the material is spread, the surface shall be rolled. Rolling shall be parallel to the road center line and shall commence at the outer edges of the road, overlapping the shoulders and progress toward the center, overlapping on successive passes by at least one-half the width of the roller, except that on superelevated curves rolling shall progress from the lower to the upper edge. Each pass shall terminate at least 3 feet (914 mm) in advance or to the rear of the end of the preceding pass. During the compaction the surface shall be dragged or bladed as necessary to fill ruts and to remove incipient corrugations or other irregularities. Rolling shall continue until the surfacing is of uniform texture and satisfactory compaction is obtained. Initial rolling shall be performed with a pneumatic-tire roller and final rolling with a 3-wheel or tandem-type steel wheel roller. Rolling shall be discontinued whenever it begins to produce excessive pulverizing of the aggregate or displacement of the mixture.

Where the compacted thickness of the road mix surface is to be more than 2 inches (50.8 mm) the mixture shall be spread from the windrow and compacted in 2 layers, the first layer to be bladed and rolled before the second layer is spread.

While the surface is being compacted and finished the Contractor shall trim the edges neatly to line.

405.11 Surface Requirements. Surface requirements shall be as specified in subsection 401.23 except that the permissible surface variance will be 6-inch (4.8 mm) in 10 feet (3.05 m).

Method of Measurement

405.12 Aggregate and bituminous material furnished for road mix bituminous pavement will be measured by units shown in the bid schedule. The quantity of road mix acceptably completed will be measured by the mile or square yard, as shown in the bid schedule.

When slag and stone (or gravel) are designated as alternative materials for pay items in the bid schedule and payment is by weight, the estimated quantities will be based on assumed average bulk specific gravities of available alternative materials. No adjustment in contract unit price will be made for variation in quantity due to difference in the specific gravity of the material actually used.

Basis of Payment

405.13 The accepted quantities of road mix bituminous pavement determined as provided above will be paid for at the contract price per specified unit for all construction, aggregates, and bituminous material complete in place which price and payment will be full compensation for the work of this section.

407.01 This work shall consist of preparing and treating an existing bituminous or concrete surface with bituminous material in accordance

with these specifications and in reasonably close conformity with th lines shown on the plans or established by the Engineer.

Materials

407.02 Bituminous Material. The type and grade of bituminous material will be specified in the bid schedule. The grade may be changed one step by the Engineer during construction at no change in unit price.

The bituminous material shall be of the type and grade called for in the bid schedule and shall conform to the following subsections:

Application temperatures of bituminous materials shall conform to subsection 702.05.

When the bid schedule calls for the use of emulsified asphalt, grade SS-1, water shall be added to the asphaltic emulsion material and thoroughly mixed therewith in such proportion that the resulting mixture will contain approximately 40 percent by volume of added water, the exact quantity of added water to be determined by the Engineer.

Construction Requirements

407.03 Equipment. The Contractor shall provide equipment for heating and applying the bituminous material. The distributor shall meet the requirements of subsection 405.05. A power broom and/or power blower shall be provided for any required cleaning of the surface to be treated.

407.04 Preparation of Surface to be Treated. The existing surface shall be patched and cleaned and shall be free of irregularities to provide a reasonably smooth and uniform surface to receive the treatment. Unstable corrugated areas shall be removed and replaced with suitable patching materials. Payment for the patching will be made at the contract unit price for the various items used unless a reconditioning item is included in the contract. The edges of existing pavement, which are to be adjacent to new pavement, shall be cleaned to permit the adhesion of bituminous materials.

407.05 Application of Bituminous Material. The bituminous material shall be uniformly applied with a pressure distributor, within the 24 hours preceding placement of the covering course.

The tack coat shall be applied in such manner as to offer the least

inconvenience to traffic and to permit one-way traffic without pickup or tracking of the bituminous material.

Tack coat shall not be applied during wet or cold weather, after sunset, or to a wet surface. The quantity, rate of application, temperature and areas to be treated shall be approved prior to application.

The surfaces of structures and trees adjacent to the areas being treated shall be protected in such manner as to prevent their being spattered or marred. No bituminous material shall be discharged into a borrow pit, gutter, or stream.

The surface shall be allowed to dry until it is in a proper condition of tackiness to receive the surface course. Tack coat shall be applied only so far in advance of surface course placement as is necessary to obtain this proper condition of tackiness. Until the surface course is placed, the Contractor shall protect the tack coat from damage.

Method of Measurement

407.06 The bituminous material for tack coat will be measured by the ton or gallon. Water added to emulsified asphalt will not be measured for payment.

Basis of Payment

407.07 The accepted quantities of tack coat, determined as provided above, will be paid for at the contract unit price per ton or gallon, as designated, for bituminous material complete in place, which price and payment will be full compensation for the work of this section. Payment will be made under:

Section 408.-PRIME COAT

Description

408.01 This work shall consist of preparing and treating an existing surface with bituminous material, and blotter material, if required, in accordance with these specifications and in reasonably close conformity with the lines shown on the plans or established by the Engineer.

Materials

408.02 Bituminous Material. The type and grade of bituminous material will be specified in the contract.

The bituminous material shall be of the type and grade called for in the bid schedule and shall conform to the following subsections:

408.03 Blotter Material. Blotter material shall meet the requirements of subsection 703.14. The material may be accepted in stockpile at the source.

Construction Requirements

408.04 Weather Limitations. Prime coat shall be applied only when the surface to be treated is dry or but slightly damp, when the surface temperature in the shade is above 55° F (13 t° c) and rising or above 60° F (15 t° c) if falling, and when the weather is not foggy or rainy.

408.05 Equipment. The Contractor shall provide equipment for heating and applying the bituminous material and for applying blotter material. The distributor shall meet the requirements of subsection 405.05.

408.06 Preparation of Surface. Immediately before applying the bituminous material all loose dirt and other objectionable material shall be removed from the surface with a power broom and/or blower as required. If the Engineer so orders, the surface shall be lightly bladed and rolled immediately prior to the application of bituminous material, in which case brooming or blowing will not be required. When so ordered by the Engineer a light application of water shall be made just before the application of bituminous material.