ITEM 423 CRACK SEALING, HOT APPLIED
423.01 Description. This work consists of preparing and sealing pavement cracks with a hot
applied crack sealant.
423.02 Materials. Furnish hot applied crack sealant, of the type specified, conforming to:
Type I ........................................... 702.17.A Type II ......................................... 702.17.B Type IV ........................................ 702.17.D Type V .......................................... 702.17.E Furnish crack sealant or mastic materials according to 702.17.
423.03 Equipment. Equipment used in the performance of this work is subject to the Engineer’s
approval and to the requirements of 108.05. For Type I crack sealant, heat the sealant in a kettle or melter constructed as a double boiler, with the space between the inner and outer shells filled with oil or other heat-transfer fluid. Use a kettle or melter with positive temperature control of the oil bath, and provide a mixing vat, mechanical agitation, and recirculating pumps. Do not apply direct heat to the sealant. For Types II and IV crack sealants, heat the sealant in a kettle or melter constructed as a double boiler, with the space between the inner and outer shells filled with oil or other heat-transfer fluid. Use a kettle or melter with separate thermometers for the oil bath and mixing vat. Equip the kettle with a full sweep type agitator. Also, equip the kettle with a 2-inch (50 mm) minimum recirculating pump to provide circulation of the materials when not applying the crack sealant. Do not apply direct heat to the sealant. For Type V mastic sealants, heat the sealant in a kettle or melter constructed as a double boiler, with the space between the inner and outer shells filled with oil or other heat -transfer fluid. Use a kettle or melter with separate thermometers for the oil bath and mixing vat. Equip the kettle with a full sweep type agitator to prevent the Type V material from separating. For Types I and IV crack sealants, use a mechanical applicator wand capable of continuously feeding the sealant through nozzles shaped to penetrate the cracks. A positive sealant flow shutoff mechanism is required. Ensure that the wand produces a band according to the tolerances of 423.07. For Type II crack sealants, use a mechanical applicator wand head capable of placing the crack sealant according to the tolerances of 423.07 while filling the cracks. A positive sealant flow shutoff mechanism is required. For Type V mastic sealants use the manufacturer’s recommendation for application equipment requirements. Use portable air compressors capable of furnishing at least 100 pounds per square inch (690 kPa) of air pressure at the nozzle. Use compressors equipped with traps that maintain the compressed air free of oil and water. Use water cleaning equipment capable of delivering water at 2000 pounds per square inch (14 MPa) of pressure from a nozzle to the crack being cleaned. Use a propane lance unit capable of producing a blast of hot air that operates at 1000 F (538 C) and a gas velocity of 2000 feet per second (600 m/s). Use mechanical and power driven routing and sawing equipment capable of following close to the path of cracks and of widening the cracks to the required dimension without causing excessive spalling or damage to the adjacent pavement. For sawing equipment, use diamond saw blades with a diameter of 8 inches (200 mm) or less.
423.04 Weather Limitations. Do not seal cracks if the surface is visibly damp or the temperature
is below 45 F (7 C).
423.05 Preparation. Fill all visible cracks according to 423.07 or as directed by the Engineer.
If routing is specified, rout cracks with an opening less than 3/4 inch (19 mm) to provide a sealant reservoir with a nominal size of 3/4 inch (19 mm) wide by 1 inch (25 mm) deep. If sawing is specified, saw all cracks to 3/4 to 7/8 inch (19 to 22 mm) wide and 7/8 to 1 inch (22 to 25 mm) deep. Use hand tools or a lightweight chipping hammer to remove all slivers of asphalt concrete less than 1 inch (25 mm) wide remaining along the c rack after sawing. Immediately before sealing, sandblast both faces of the sawed crack to remove all contamination and to texture the faces. If the crack below the sealant reservoir is greater than 3/8 inch (10 mm) wide, insert a backer rod into the crack to form the bottom of the reservoir at the proper depth. For Type V mastic sealant, clean cracks and joints to remove debris and any loose deteriorated pavement. For crack or joint reservoir depths greater than 2.5 inches (62.5 mm), fill according to
423.07 Stop application if the material becomes separated (asphalt and aggregate are not homogenous).
Before applying the hot sealant, clean cracks by an approved method or methods to remove dust, dirt, moisture, vegetation, and other foreign material. Keep the cracks clean and dry until all sealing operations are completed.
423.06 Mixing Type II. Use weigh tickets in determining the specified proportion of fiber to
blend into the binder. Add fibers to the binder, and mix thoroughly in the kettle. Type II crack sealant may also be prepackaged per 702.17.B. Do not allow the temperature of the sealant in the field application to exceed the safe heating temperature recommended by the manufacturer.
423.07 Application of Sealant. Perform the crack sealing operation within 250 feet (76 m) of
the cleaning operation. Seal only cracks that are wide enough to permit entry of sealant. Seal tightly closed cracks (less than 1/4-inch (6 mm) wide) only if they show signs of raveling or spalling. For Types I, II, and IV sealants, do not seal cracks greater than 1-inch (25 mm) wide, and do not seal spalls or cavities greater than 4 inches (100 mm) wide, unless otherwise directed. For Types I and IV crack sealants, fill the entire crack reservoir with the sealant from the bottom up to approximately 1/16 inch (2 mm) above the pavement surface. Immediately scrape the filled cracks with a V-shaped or U-shaped squeegee, or similar hand tool, to smooth the overfill. This may require more than one application of sealant. The Engineer will not accept the work if the band of sealant on the pavement surface is greater than 2 inches (50 mm) wide. For Type II crack sealants, place the sealant such that it fills the cracks with a band of sealant within 2 to 4 inches (50 to 100 mm) wide. The Engineer will not accept the work if the thickness on the pavement is greater than 3/16 inches (5 mm). For Type V mastic sealant, place the sealant such that it fills the cracks and joints with a band on all sides, 2 inches (50 mm) wide beyond the edges of the deteriorated area and does not exceed 1/8 inch (4 mm) thickness above the pavement. If the crack o r joint depths are greater than 2.5 inches (62.5 mm), fill the crack or joint in multiple lifts allowing the first lift to cool prior to adding the final lift.
423.08 Opening to Traffic . Do not allow traffic on the sealant until it has cured and the
possibility of tracking no longer exists. However, if the Engineer determines it is necessary to allow traffic to pass over the sealant before adequate curing, dust Portland cement or other approved material over sealed cracks to eliminate pickup or tracking.
423.09 Method of Measurement. The Department will measure Crack Sealing, of the type
specified, by the number of pounds (kilograms) of hot applied sealant in place, completed, and accepted. The Department will measure Crack Sealing, of the type specified, by the square yards of sealing completed and accepted.
423.10 Basis of Payment. The Department will pay for accepted quantities at the contract prices
as follows: Item Unit Description 423 Pound (Kilogram) Crack Sealing, Type I or Square Yard (Square Meter) 423 Pound (Kilogram) Crack Sealing with Routing, Type I or Square Yard (Square Meter) 423 Pound (Kilogram) Crack Sealing with Sawing, Type I or Square Yard (Square Meter) 423 Pound (Kilogram) Crack Sealing, Type II or Square Yard (Square Meter) 423 Pound (Kilogram) Crack Sealing, Type IV or Square Yard (Square Meter) 423 Pound (Kilogram) Crack Sealing, Type V or Square Yard (Square Meter)
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