191 SECTION 407 FOG SEAL 407.1 -DESCRIPTION : This work shall consist of preparing and fog sealing an existing roadway surface with asphalt material in accordance with these Specifications and in reasonably close conformity with the lines shown on the Plans or established by the Engineer. 407.2 -MATERIALS : Materials shall be from an approved source and conform to the requirements of the follow ing Subsections: MATERIALS SUBSECTION TYPE Asphalt Emulsion 705.4 SS-1 or SS -1h Cationic Emulsified Asphalt 705.11 CSS-1 or CSS -1h Non-Tracking Asphalt Material 705.13 NTSS -1HM or similar* * Refer to MP 401.02.25 for a list of Certified Asphalt Materials 407.2.1 -Quality Control: Quality control is the responsibility of the Contractor as specified in 106.1. Quality control shall consist of calibrating the distributor to the proper application rate, verifying the volume and temperatu re measuring devices, and when performed, assuring and documenting that the proper dilution rate is maintained. 407.2.1.1 -Acceptance Testing: Approval of asphalt emulsions used for fog seal material will be handled by the Materials Control, Soils and Te sting (MCS&T) Division. MCS&T maintains a list of all approved asphalt emulsion sources and grades. The local District Materials Section can provide a copy of the latest list. The list is also posted on the MCS&T web page under the heading Approved Sour ce/Product Listing. The use of non-approved material without prior testing by MCS&T may result in nonpayment of the item. CONSTRUCTION METHODS 407.3 -WEATHER RESTRICTION : Fog seal shall be applied only when the weather and existing surface are satisfactory to the Engineer and when the temperature of the surface is 50°F or above. When the surface temperature is less than 60°F, care must be exercised to assure that the fog seal sets prior to resuming traffic. 407.4 -EQUIPMENT : Equipment for Surface Preparation may include a power broom and power blower, and a broom drag. Equipment may also include scrapers, hand brooms, shovels, and other equipment as may be necessary to thoro ughly clean the base or surface. Equipment for distribution of asphalt material shall include equipment for heating asphalt material, and a self -powered asphalt material pressure distributor. Equipment for heating asphalt material to the required temper ature shall consist of a retort coil so designed that steam will not be introduced into the material and shall not degrade the emulsion. The distributor shall be so designed, equipped, maintained and operated that asphalt material at even heat may be appl ied 192 uniformly on variable widths of surface up to fifteen ( 15) feet at readily determined and controlled rates from 0.05 to 0.15 gal/sy with uniform pressure and with an allowable variation from any specified rate not to exceed 0.02 gal/sy. The distributo r shall also have a cab -metering system that will automatically adjust the flow of the asphalt material as the speed of the truck changes and allow the operator to adjust the rate of application from the cab of the truck. Distributor equipment shall inclu de a tachometer, pressure gages, and accurate volume measuring devices or a calibrated tank, and a thermometer for measuring temperatures of tank contents. Distributors shall be equipped with a power unit for the pump, and full circulation spray bars adju stable laterally and vertically. A manifold connection shall be provided and hand - spraying equipment shall be available to cover areas and patches inaccessible to the distributor. 407.5 -PREPARING AND REPAIRING EXISTING SURFACES : No fog seal shall be applied until breaks, holes, depressions, and other irregularities in the existing surface have been repaired and cured sufficiently to permit the fog seal to be placed in a uniform application. 407.6 -CLEANING AND SWEEPING : Immediately before application, the existing surface shall be swept and thoroughly cleaned by the use of tools or machinery as may be required to remove all loose aggregate, mud, dirt, dust, and other caked or loose material foreign to the type of surface to be placed. Cleaning shall be done to a minimum width of one foot on each side beyond the width of the surface to be treated including the shoulder. 407.7 -APPLICATION OF ASPHA LT MATERIAL : Except when required to maintain traffic, the work shall be done on the full width of the section. Joints shall overlap by two ( 2) to six (6) inches. After the surface has been cleaned, when called for, and is in a dry condition, the asphalt material shall be applied by means of a distributor. The spray bar shall be raised to a sufficient height so as to uniformly and completely coat the entire surface . The rate of application of asphalt material shall be as recommended in subsection 407.10, or as determined by the Engineer. Application temperatures of the asphalt material shall be within the range specified in Subsection 705 for the particular materi al being used. Anionic asphalt emulsion grades SS -1 and SS -1h, and cationic emulsion grades CSS -1 and CSS -1h, may be diluted at a 1:1 ratio by addition of water to the emulsion. Dilution shall occur by the manufacturer at the terminal. The surfaces of s idewalks, curbs, other structures, and trees adjacent to the area being treated shall be protected in such a manner as to prevent being spattered or marred. Material used for such protection shall be removed and disposed of in an appropriate manner. The distributor shall not be cleaned or discharged within the right -of-way, into borrow pits, or so as to pollute or block water courses. 407.8 -APPLICATION OF COVER AGGREGATE : Any fog seal material applie d 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. 193 407.9 -PROTECTION OF THE PAVEMENT AND TRAFFIC CONTROL : The Contractor shall be responsible for the protection of the surface against 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 apply for regulating traffic.
407.10 Quantities of Materials :
The application rates referenced in Table 407.10 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 tha t 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, the residual asphalt content is defined as the amount of asphalt remaining on the pavement surface after all wat er has evaporated from the emulsion. Unless otherwise specified on the Plans, the recommended application rates for undiluted and diluted asphalt fog seal shall be as specified in Table 407.10. These rates are provided for guidance and may be adjusted as directed by the Engineer based on field conditions. TABLE 407.10 Surface to be Sealed Application Rate (gal/sy) (Note 1) Undiluted Diluted (1:1) Oxidized HMA 0.06 – 0.08 0.12 – 0.15 Chip Seals See Specification 405 Note 1: Application rates are for slow setting emulsions grades (SS and CSS) that contain approximately 60% asphalt material. Non -Tracking Emulsions may contain different asphalt contents. Refer to manufacturer’s recommendations for application rates.
407.11 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 incorporated into the operations have been determined, except when authorized by the Engineer. The quantity of “Asphalt Material” for fog seal 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 fog seal shall be considered incidental to the work.
407.12 Basis of Payment :
The quantiti es, 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 acce ptable manner, included all labor, tools, equipment, supplies, and incidentals necessary to complete the work.
407.13 Pay Item :
ITEM DESCRIPTION UNIT 407001 -* Non-Tracking Fog Seal Gallon 407002 -* Fog Seal Gallon *Sequence number