196 surface courses of any type shall be applied to the tacked surface until the asphalt materia l is thoroughly “set” (see Note 1 in Section 408.3) . Tack c oat shall not be applied over newly placed patching and leveling courses. However, to facilitate construction, minor (spot) areas that have been tacked, patched and leveled may be retacked and the quantity so used will be included for payment as part of t he normal tack coat operation. The intent of the two preceding sentences, in conjunction with the next to the last paragraph of subsection 401.13, is (1) to provide one tack coat application on the existing surface, although two applications, one over one under, for minor (spot) patching and leveling area, are permitted as indicated above, and (2) to limit payment for such operations to one application of the tack coat upon the existing surface for the entire project. The surfaces of sidewalks, curbs, oth er structures, and trees adjacent to the area being treated shall be protected in such a manner as to prevent their being spattered or marred. Material used for such protection shall be removed and disposed of in a satisfactory manner. The distributor shall not be cleaned or discharged win the right -of-way, into borrow pits, or so as to pollute or block water courses. 408.8 -APPLICATION OF COVER AGGREGATE : Any tack coat material applied in excess of the requirements shall be removed or covered with a blotter course of dry sand or stone chips as directed by the Engineer. 408.9 -JOINTS : Longitudinal joints shall be treated using an application rate that will tho roughly coat the vertical face without excessive runoff
408.10 Protection of The Pavement and Traffic Control :
The Contractor shall be responsible for the protection of the surface a gainst damage by their equipment and personnel. Traffic shall not be permitted on any part of the work under construction until the treatment has cured sufficiently to prevent raveling or picking up under traffic. The applicable provisions of 636 shall a pply for regulating traffic.
408.11 Quantities of Materials :
The application rates referenced in Table 408.11 shall be used as guide to assure the proper amount of asphalt is distributed over the pavement surface under various pavement conditions. The undiluted application rate refers to the unmodified emulsion that meets all standard specifications of the specified grade. When an SS or CSS grade emulsion is diluted with water at the allowable 1:1 ratio t he residual asphalt content (the amount of asphalt remaining on the pavement surface after all water has evaporated from the emulsion) will be cut in half. Therefore the distribution rate must be doubled in order to obtain the same residual asphalt applic ation as the undiluted emulsion. Unless otherwise specified on the Plans, the recommended application rates for undiluted and diluted asphalt tack coat shall be as specified in Table 408.11. These rates are provided for guidance and may be adjusted as directed by the Engineer to assure a uniform application that covers the entire pavement, and to assure that excessive asphalt does not cause a slippage plane between two pavement courses. TABLE 408.11 Condition of Existing Pavement Application Rate (gal/sy) (Note 2) Undiluted Diluted (1:1) (Note 3) New HMA (Note 4) 0.04 – 0.05 0.08 – 0.10 Oxidized HMA 0.07 – 0.10 0.13 – 0.20 Milled Surface 0.10 – 0.13 0.20 – 0.27 PC Concrete 0.07 – 0.10 0.13 – 0.20 Note 2: Application rates are for slow setting emulsions grades (SS and CSS) that contain approximately 60% asphalt material. Rapid setting emulsion grades may contain slightly higher or lower asphalt contents, but can usually be applied within the same applicati on range. Note 3: Dilution rate only applies to SS and CSS grades. Note 4: Tack coat is normally not needed over a layer of new HMA that has been placed within the last few days, as long as the underlying new layer has not become dirty under traffic or from windblown dust.
408.12 Method of Measurement :
No materials shall be removed from the Project for any purpose until the operation has been completed and the quantities of materials incorporat ed into the operations have been determined, except when authorized by the Engineer. The quantity of “Asphalt Material” for tack coat shall be the number of gallons, prior to dilution, incorporated into the completed work. Any applicable dilution rates, shall be supplied to the Engineer by the Contractor on the material delivery ticket. Dry sand or stone chips used as a blotter course due to excessive use of tack coat shall be considered incidental to the work. When items for maintaining traffic are inc luded in the Contract, they will be measured and paid as provided in Section 636.
408.13 Basis of Payment :
The quantities, determined as provided above, will be paid for at the contract unit prices bid for the items listed below, which prices and payments shall be full compensation for furnishing all the materials and doing all the work prescribed in a workmanlike and acceptable manner, included all labor, tools, equipment, supplies, and incidentals necessary to complete the work.
408.14 Pay Item :
ITEM DESCRIPTION UNIT 408001 -* Non-Tracking Asphalt Material Gallon 408002 -* Asphalt Material Gallon *Sequence number SECTION 409-BLANK