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Letter suffixes will be added to pay item numbers 410 (2) and 410 (4) to designate alternative types of materials to be bid on.

Section 411.-BITUMINOUS PRESERVATIVE

TREATMENT

Description

411.01 This work shall consist of placing a double application of bituminous material with an aggregate cover on a prepared roadbed, in accordance with these specifications, in reasonably close conformity with the lines shown on the plans or established by the Engineer.

Materials

411.02 Bituminous Materials. The type and grade of bituminous material will be specified in the contract. The grade may be changed one step by the Engineer during construction at no change in unit price. The bituminous material may be conditionally accepted at the source, subject to the provisions of clause 10 of the General Provisions.

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

Slow-curing liquid asphalt (SC)

Medium-curing liquid asphalt (MC)

Tar

702.03

702.03

702.02

Application temperatures of bituminous materials shall conform to subsection 702.05.

411.03 Aggregate. Aggregate shall meet the requirements of subsection 703.13 for the gradations called for in the bid schedule. The aggregate may be accepted in stockpile at the source, subject to the provisions of clause 10 of the General Provisions.

Construction Requirements

411.04 Weather Limitations. Bituminous material shall be applied only when the surface to be treated is dry or but slightly damp, when the atmospheric temperature in the shade is above 55° F. and rising or above 60° F. if falling, and when the weather is not foggy or rainy.

411.05 Equipment. The equipment used by the Contractor shall include a power broom, blade grader, broom dragging equipment, a power roller weighing not less than 5 tons, blotter spreading equipment that can be so adjusted as to spread accurately the given amounts per square yard, equipment for heating bituminous material, and a pressure distributor conforming to the requirements of subsection 405.05. 411.06 Preparation of Surface for Treatment. If the surface is well bonded and does not require blade shaping, or if the surface has been specially compacted, it shall be thoroughly swept with a power broom immediately prior to the first application of the bituminous material.

However, if it is necessary to remove corrugations or other irregularities, the surface to be treated shall be lightly scarified or disked immediately prior to the first application of bituminous material and shaped with a blade grader. When scarifying or disking, care shall be taken not to disturb the base or roadbed to a depth greater than is necessary for blade shaping of the surface. In general, the depth loosened by scarifying or disking shall not exceed 1 inch, unless otherwise directed by the Engineer.

If the Engineer so orders, the road surface shall be lightly bladed and rolled immediately prior to the application of bituminous material. In this case, brooming or blowing will not be required. If a dusty surface results from the above operation, a light application of water shall be applied shortly before the application of bituminous material to improve coverage and penetration if so ordered by the Engineer.

Where indicated on the plans, the roadbed shall be prepared by special compacting.

411.07 Application of Bituminous Material. Bituminous material of the type and grade specified shall be applied in two applications at the rates set by the Engineer and at a temperature within the range called for in subsection 702.05 for the particular material being used. The combined amount of the two applications shall be as directed by the Engineer, to a maximum rate of 0.75 gallon per square yard. During the applications, the surfaces of all adjacent structures and trees shall be protected in such manner so as to prevent their being spattered or marred. No bituminous material shall be discharged into a borrow pit, gutter or stream.

Bituminous material shall be applied in lanes of approximately one-half the width of the completed surface, unless its extreme width makes such application impracticable in which case bituminous material shall be applied in more than two lanes as required.

411.08 Spreading Aggregates. After the first application of bituminous material has been made, it shall be left un

disturbed to penetrate the surface for a period of not less than 4 hours. It shall then be covered by aggregate of the designated grading spread from approved equipment in just sufficient quantity to prevent adherence of the bituminous material to the equipment using the surface. In covering the first lane of adjacent lanes, a strip at least 8 inches wide shall be left uncovered where the two lanes join, to permit a slight overlap of the bituminous material.

The first application of bituminous material shall be allowed to cure for a period of not less than 5 days. During this curing period the road shall be opened to traffic and the aggregate shall be broomed and kept free of corrugations. Additional aggregate shall be added wherever bleeding occurs. Holes that develop shall be patched with bituminous material and aggregate. All dirt, dust, and excess cover material shall then be removed by thorough sweeping and the second application of bituminous material made.

Immediately following the second application of bituminous material, blotter material in amounts of from 25 to 35 pounds per square yard shall be spread from the approved equipment. The moisture content of this aggregate shall not be more than 5 percent of the dry weight of the material at the time of application.

411.09 Brooming and Rolling. Following each spreading of aggregate the treated surface shall be smoothed by brooming and rolled with a power roller. The surface shall be kept smooth under traffic by brooming, for a period of not less than 5 days. When directed by the Engineer, any excess cover material shall be broomed from the surface or, if bleeding develops, surplus aggregate shall be broomed over the surface. If there is insufficient surplus material available, additional aggregate may be spread from a truck.

411.10 Stockpiling. When indicated on the plans, aggregate of the type called for shall be stockpiled in the amounts and at the locations so indicated. Stockpiles shall be shaped as directed by the Engineer. Prior to stockpiling the material, the sites shall be cleared, cleaned, and leveled by the Contractor.

When indicated on the plans and called for in the bid schedule, all or a portion of the aggregate to be stockpiled shall be treated with bituminous material of the type used in the base preservative treatment. The bituminous material shall be applied to dry aggregate in the amounts set by the Engineer and the two materials shall be mixed thoroughly in a portable mixer, by turning with a blade grader, or by other methods approved by the Engineer. After treatment the stockpiles shall be shaped as directed.

Method of Measurement

411.11 Bituminous material will be measured by the ton or gallon and aggregate will be measured by the ton or cubic yard.

Measurement of bituminous treated aggregate placed in stockpile will be made prior to addition of the bituminous material, which will be measured separately.

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 differences in the specific gravity of the material actually used.

Basis of Payment

411.12. The accepted quantities of bituminous preservative treatment determined as provided above will be paid for at the contract price per ton or gallon for bituminous material and per ton or cubic yard for aggregate complete in place, which price and payment will be full compensation for the work of this section.

Payment will be made under:

Pay item

411(1) Aggregate, bituminous preserva-
tive treatment, grading

Pay unit

Cubic yard.

411(2) Aggregate, bituminous preserva-
tive treatment, grading

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When more than one grading is specified, letter suffixes will be added to the item numbers to differentiate between gradings.

Pay item numbers 411 (2) and 411(4) will have numerical suffixes added to indicate alternative types of material to be bid on.

Section 412.-AGGREGATE SURFACE COURSE

Description

412.01 This work shall consist of a course composed of gravel or crushed aggregate, whichever is called for in the bid schedule, placed on a prepared surface in accordance with these specifications, in reasonably close conformity with the lines, grades, thicknesses, and typical cross sections shown on the plans or established by the Engineer.

Materials

412.02 Aggregate. Aggregate shall meet the requirements of subsection 703.06 for the type and grading designated in the bid schedule.

412.03 Chemical Additives. Chemical additives if required, shall meet the applicable requirements of the following subsections:

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Construction Requirements

412.04 Construction details shall conform to the requirements of subsections 304.04 through 304.06.

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