Table 410–1.—Quantities of materials per square yard (using cutback asphalt, asphalt cement, or tar) for bituminous

The weights given in tables 410-1 and 410-2 are those of aggregates having a bulk specific gravity of 2.65, as determined by AASHO T 84 and T 85. Proportionate corrections will be made when the aggregate furnished on the job (job aggregate) has a bulk specific gravity above 2.75 or below 2.55. In such case the corrected amount will be the product of the number of pounds shown in table 410–1 or table 410-2 multiplied by the ratio of the bulk specific gravity of the aggregate to 2.65.

The amounts given in these tables are approximate and the exact amounts will be set by the Engineer for each application and spreading. Total amounts of bituminous material per square yard may be varied by the Engineer as necessary to fit conditions, but the total amount of aggregate per square yard, after adjustment for specific gravity, will not be changed, except that the Engineer may order that a portion of it be placed in stockpiles, and similarly, he may order some of the apportionment for stockpiling used in the surface treatment.

Table 410-2.-Quantities of materials per square yard (using emulsified asphalt) for bituminous surface treatments

410.02 Bituminous Material. The types and grades 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:

Medium-curing liquid asphalt (MC)

Rapid-curing liquid asphalt (RC)

Emulsified asphalt

Asphalt cement

Tar

Cationic emulsified asphalt

702.03

702.03

702.04

702.01

702.02

702.04

Application temperatures of bituminous materials shall conform to subsection 702.05.

410.03 Aggregates. Aggregates and blotter material shall meet the requirements of subsection 703.13 and 703.14 for

the sizes specified. The material may be accepted in stockpile at the source, subject to the provisions of clause 10 of the General Provisions.

Construction Requirements

410.04 General. Surface treatments shall be applied only when the existing surface 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.

The equipment used by the Contractor shall include a power broom and/or a power blower, dragging equipment, a selfpowered roller (3-wheel or tandem, weighing between 5 and 8 tons) or a pneumatic-tire roller, aggregate spreading equipment that can be so adjusted as to spread accurately the given amounts per square yard, a distributor, and equipment for heating bituminous material. For designations AT60, AT-70, AT-110, E-60, E-70, and E-110 the equipment shall also include a pneumatic-tire motor grader.

The pressure distributor shall conform to the requirements of subsection 405.05.

Pneumatic-tire rollers shall have a total compacting width of not less than 60 inches and the gross weight shall be adjustable within the range of 200 to 350 pounds per inch of compacting width. The operating weight shall be as directed by the Engineer.

Other equipment of proven performance may be used by the Contractor in addition to or in lieu of the specified equipment when approved by the Engineer.

Bituminous surface treatment shall be applied using quantities and sequence of operations as outlined in subsection 410.01. Each spreading of aggregate shall immediately follow application of bituminous material, except where the first spreading is required to be placed directly on the previously bituminized surface.

In the case of designations AT-110 and E-110 surface treatment, an interval of at least 24 hours shall elapse between application of the third layer and that of the fourth, during which period the surface shall be opened to traffic and maintained by the Contractor by brooming and rolling. Prior to placing the first layer of surface treatment, loose dirt and other objectionable material shall be removed from the existing surface. If so directed by the Engineer the surface shall be cleaned with a power broom or power blower.

410.05 Application of Bituminous Material. Bituminous material shall be so applied that uniform distribution is ob

tained at all points. Building paper shall be spread on the surface for a sufficient distance back from the ends of each application so that flow through the nozzles may be started and stopped on the paper and so that all nozzles will operate properly on the entire length being treated. Building paper so used shall be removed and disposed of in a manner satisfactory to the Engineer. Application temperature shall be within the range called for in subsection 702.05 for the particular bituminous material being used. During all applications the surfaces of adjacent structures and trees 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.

410.06 Application of Aggregate. Initial spreading of each layer of aggregate for all designations of surface treatment shall be done with the aggregate spreading equipment specified. Before the bituminous material is applied, sufficient seal aggregate to cover the distributor load of bitumen shall be in trucks on the roadway at the site of the work. Vehicles spreading aggregate shall be operated in such a manner that bituminous material will be covered before wheels pass over it. Supplemental spreading and smoothing of the first layer of designations AT-60, AT-70, AT-110, E-60, E-70, and E-110 shall be done with the motor grader, drag, or spreader approved by the Engineer. All other supplemental spreading and smoothing shall be done with a broom drag, approved spreader, or hand methods where necessary.

Following spreading and smoothing, each layer of aggregate shall be rolled as directed. Except where a motor grader or approved drag is used for supplemental shaping and smoothing, broom dragging shall accompany rolling. The final layer of treatment in all cases shall be alternately broom dragged and rolled thoroughly until the surface is fully compacted and bonded to full width. The Contractor shall furnish a pilot car and driver to conduct traffic over completed surface treatments at a maximum speed of 25 miles per hour for the first 24 hours after aggregate is applied.

Method of Measurement

410.07 Bituminous material will be measured by the ton or gallon and aggregates will be measured by the ton or cubic yard.

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

410.08 The accepted quantities of bituminous surface 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 aggregates complete in place, which price and payment will be full compensation for the work of this section.

Payment will be made under: