ITEM P-603 BITUMINOUS TACK COAT

DESCRIPTION

603-1.1 This item shall consist of supplying and applying bituminous material to a previously prepared, bonded and/or bituminized binder, leveling, or base course or existing pavement in accordance with these specifications and to the width shown on the typical cross section on the plans.

603-1.2 QUANTITY OF MATERIAL. The approximate amount of bituminous material per square yard for the tack coat shall be as provided in the table. The exact amount shall be as ordered by the engineer.

TABLE 1.-Quantity of Material

terial to be used shall conform to the kind, grade, and specifications as follows:

Rapid-curing cut-back asphalt, grade RC-2, RC-3, RC-4–conforming to the requirements of A. A. S. H. O. Specification M-81. The grade of cut-back asphalt shall be indicated in the proposal or shown on the plans. The asphalt cement shall meet the requirements of A. A. S. H. O. Specification M-20. The penetration grade shall be between 100 and 150, or as directed by the engineer.

The 90+ asphalt cement shall be homogeneous, free from water, and shall not foam when heated to a temperature of 347° F. The cement shall meet the requirements of Table 2.

318

The emulsified asphalt shall be homogeneous, of such character that it will mix with distilled water in all proportions, and shall meet the following requirements:

TABLE 3.—Requirements for Emulsified Asphalt

Residue at 325° F., percent..

Demulsibility: 35 c. c. N/50 CaCl2, not less than, percent..

Sieve Test, not more than, percent..

Settlement 5 days, not more than, percent.

Sampling Material.

T-40

The residue from distillation shall have the following characteristics:

Specific Gravity at 77° F., not less than..

T-43

0.96

Penetration at 77° F., 100 g., 5 sec..

Soluble in Carbon Tetrachloride, not less than, percent.

603-3.1

CONSTRUCTION METHODS

WEATHER LIMITATIONS. The tack coat shall be applied only when the existing surface is dry, when the atmospheric temperature is above 60° F., and when the weather is not foggy or rainy. The temperature requirements may be waived, but only when so directed by the engineer.

603-3.2 EQUIPMENT. The equipment used by the contractor shall include a self-powered pressure bituminous material distributor, and equipment for heating bituminous material.

The distributor shall have pneumatic tires of such width and number that the load produced on the course shall not exceed 650 pounds per

inch of tire width, and shall be so designed, equipped, maintained, and operated that bituminous material at even heat may be applied uniformly on variable widths of surface at readily determined and controlled rates of from 0.05 to 2.0 gallons per square yard, with a pressure range of from 25 to 75 pounds per square inch, and with an allowable variation from any specified rate not to exceed five (5) percent. Distributor equipment shall include a tachometer, pressure gauges, volume measuring devices, and a thermometer for reading temperatures of tank contents.

Equipment for heating bituminous material shall consist of a tank with steam coils so designed that steam will not be introduced into the material. Other approved equivalent heating facilities may be used.

603-3.3 APPLICATION OF BITUMINOUS MATERIAL. Immediately before applying the tack coat, if the surface is sufficiently bonded, the full width of surface to be treated shall be swept with a power broom equipped with blower, supplemented by hand brooms, if necessary, or otherwise as directed by the engineer. In any case care shall be taken to remove all loose dirt and clay or other loose and objectionable material.

After the operation of removing the dust has been completed, and prior to the application of the tack coat, an inspection shall be made of the binder, leveling, or base course to determine its fitness to receive the bituminous material. That portion of the surface of the course proposed for immediate treatment must be dry and altogether in a satisfactory condition.

The application of the bituminous tack material shall be made by means of a pressure distributor of approved type, and shall be made at the pressure and in amounts as directed by the engineer. The temperature of application for cut-back asphalt and asphalt cement shall be as follows:

The temperature of application for the 90+ asphalt cement and the emulsified asphalt shall be as shown in the tables.

Following the application, the surface shall be allowed to cure without being disturbed for such period of time as may be necessary to permit drying out and setting of the tack coat, which period shall be determined by the engineer. The surface shall then be maintained by the contractor until the next course has been placed. Suitable precautions shall be taken by the contractor to protect the surface against damage during this interval, including any sand necessary to blot up excess bituminous material. 603-3.4 BITUMINOUS MATERIAL CONTRACTOR'S RESPONSIBILITY. Samples of the bituminous material that the contractor proposes to use, together with a statement as to its source and character, must be submitted and approval obtained before use of

such material begins. The contractor shall require the manufacturer or producer of the bituminous material to furnish material subject to this and all other pertinent requirements of the contract. Only those materials that have been demonstrated by service tests as satisfactory for the intended use will be acceptable.

The contractor shall furnish vendor's certified test report for each carload, or equivalent, of bituminous material shipped to the project. The report shall be delivered to the engineer before permission is granted for use of the material. The furnishing of the vendor's certified test report for the bituminous material shall not be interpreted as a basis for final acceptance. All such test reports shall be subject to verification by testing of samples of materials as received for use on the project.

603-3.5 FREIGHT AND WEIGH BILLS. Before the final estimate is allowed, the contractor shall file with the engineer receipted bills where railroad shipments are made, and certified weigh bills when materials are received in any other manner, of the bituminous materials actually used in the construction covered by the contract. The contractor shall not remove bituminous material from the tank car or storage tank until the initial outage and temperature measurements have been taken by the engineer, nor shall the car or tank be released until the final outage has been taken by the engineer.

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

METHOD OF MEASUREMENT

603-4.1 The gallonage of bituminous tack coat to be paid for shall be the number of gallons of the material used as ordered for the accepted work, corrected to gallons at 60° F., in accordance with A. S. T. M. Designation D-206, for asphalt materials and in accordance with an appropriate formula or table for emulsified asphalt; provided, however, that the measurement shall be in tons (2,000 pounds) in cases where the bid schedule calls for tons of bituminous material.

BASIS OF PAYMENT

603-5.1 The gallonage or tonnage of bituminous tack coat, determined as provided above, shall be paid for at the respective contract unit price per gallon or ton in the bid schedule for bituminous tack coat, which price and payment shall be full compensation for furnishing, delivering, and applying the material; for cleaning the course; for covering excess bituminous material; and for all labor, equipment, tools, and incidentals necessary to complete the item.

Payment will be made under:

Item P-603-5.1 Bituminous Tack Coat-per gallon or per ton.

ITEM P-604 BITUMINOUS SEAL COAT

DESCRIPTION

604-1.1 This item shall consist of a seal coat of bituminous material with cover aggregate, constructed on the properly cured wearing surface in accordance with these specifications and to the width shown on the typical cross section on the plans.

604-1.2 QUANTITIES OF MATERIALS PER SQUARE YARD. The approximate amounts of materials per square yard for the seal coat shall be as provided in Table 1. The exact amounts to be used shall be determined by the engineer.

shall meet the gradation given in Table 2. The test for gradation shall be made using A. A. S. H. O. Method T-27.

TABLE 2.-Requirements for Gradation of Aggregate

Cover aggregate for seal shall be a light colored material consisting of crushed stone free from dirt or organic matter. Acceptable material shall be equal in color and reflectivity to that from approved

sources.