472ASPHALT FOG SEAL FOR ASPHALT SEAL COATS

472.1DESCRIPTION—This work is the treatment of a n asphalt seal coat with an application of asphalt

material.

472.2MATERIAL—

TABLE A Fog Seal Materials Application Temperature (F) Class of Material Type of Material Minimum Maximum CSS-1h Cationic Emulsified Asphalt 70 150 SS-1h Emulsified Asphalt 70 150 SS-1hP Polymer-Modified Emulsified Asphalt 70 150 CSS-1hP Cationic Polymer-Modified Emulsified Asphalt 70 150 If required or directed, dilute emulsified materials using emulsion and water or a compatible emulsifying solution. Do not exceed dilution of less than 38% asphalt residue. All dilution must be done by the emulsi fied asphalt supplier at the emulsified asphalt supplier plant location. Provide a Bill of Lading from the emulsified asphalt supplier certifying the base emulsified asphalt properties before dilution, the quantity of emulsified asphalt, and the water added for dilution, or certify the diluted product. Diluted emulsified asphalt must be applied within 48 hours after dilution. Dilution of asphalt emulsion in the field is not allowed.

TABLE B Fast Break Fog Seal Materials Application Temperature (F) NTT Non-Tracking Tack 140 180 CNTT Cationic Non-Tracking Tack 140 180 *Proprietary Fast Break Materials *As listed in Bulletin 15 * * • Do not dilute NTT/CNTT.

• *Proprietary Fast Break Fog Seals Materials: Conditionally approved in Bulletin 15 according to manufacturer's recommendations. Application Temperatures according to manufacturer's recommendations. If dilution is allowed according to manufacturer’s recommendations, do not exceed dilution of less than 38% asphalt residue. Dilution of asphalt emulsion in the field is not allowed.

• All Fast Break Fog Seal Materials must achieve a break/cure within 30 minutes or less.

472.3CONSTRUCTION—Place the fog seal on an asphalt seal coat constructed as specified in Section

470, or as directed by the Representative . Allow the seal coat to cure a minimum of 2 days before fog sealing. Place the fog seal application within 2 to 30 days after the last day of the seal coat placement, unless otherwise directed in writing by the District Executive.

60F. Do not apply emulsified asphalt if, in the Representative's opinion, rain is imminent or if freezing temperatures are expected within 8 hours after application.

the pavement with a motorized broom to remove excess seal coat aggregate, debris, and dust. If the seal coat surface aggregate is damaged by the sweeping operation, adjust the operation until a satisfactory clean surface is achieved. Cover manholes, valve covers, sensors, etc. to prevent adherence of the emulsified asphalt. Remove protective coverings before opening the road to traffic.

requirements of Section 460.3(b). Place emulsified asphalt on completed seal coated areas. Construct a 100-foot test strip. Review the application of emulsified asphalt and adjust the application rate as needed. Target the Residual Asphalt Rate between 0.02 to 0.05 gallons per square yard. Determine the distributor’s application rate in the field according to PTM No. 747. Apply the emulsified asphalt to minimize the amount of overspray.

over the surface treatment within 5 minutes of applying the emulsified asphalt. The fine aggregate application rate is 2 to 5 pounds per square yard . Lightly cover remaining spots of excess emulsified asphalt with fine aggregate, before opening to traffic. Sweep the pavement with a motorized broom before opening to traffic.

place permanent pavement markings on the fog seal until 3 days after the last day of fog seal placement.

sealed roadways to traffic. Do not allow traffic on the emulsified asphalt until it has cured.

472.4MEASUREMENT AND PAYMENT—