This work consists of cleaning
and preparing pavement cracks and placing a hot crack joint sealant.
The hot applied crack sealer must
be the type specified on the plans and meet the requirements of 423.02. Crack sealants are known as Type I, Type II,
Type III, or Type IV.
Type I crack sealant must be
approved by the Laboratory before shipping to the project. Type II and III joint sealants are mixed on
the project and require the use of PG 62-22 binder and fibers. Binder is accepted based on a certification
program while the fiber manufacturer must be on the Qualified Product
List. Type II can be a premixed and
prepackaged sealant. This type of
sealant requires certified test data.
Type IV sealant is a
prepackaged and preapproved mixture that requires the fiber manufacturer’s
representative be present during the application to ensure proper
application. The Contractor must submit
a 10 pound sample of the base binder and 10 pounds of fiber to the Laboratory
for approval.
All equipment used for crack
sealing must meet the Engineer’s approval and the requirements of 108.05.
Type I sealant must be heated
in a kettle or melter constructed as a double boiler. The space between the kettle and outer shell
must be filled with oil or other heat-transfer fluid. The melter must have temperature control of
the oil and have a mixing vat, mechanical agitation, and recirculation
pump. Heat cannot be applied directly to
the sealant.
Type II, III, and IV sealants
must be heated in a double boiler as described above for Type I sealant; there
must be separate thermometers for the oil and the mix vat. A full sweep agitator and a minimum 2-inch
recirculation pump must be used in the kettle.
Heat cannot be applied directly to the sealant.
For all sealant types, a
mechanical applicator wand with a flow shutoff valve is required. Nozzles on the wand must be shaped to
penetrate the crack.
Air compressors are used to
clean out the cracks prior to placing the sealant. Air compressors must be a minimum of 100 psi
and have water and oil traps.
Water cleaning equipment must
deliver water at 2,000 psi to the crack being cleaned.
A propane lance that produces
hot air and operates at 1,000 °F, with a gas velocity of 2,000 feet per second,
must be used to dry the crack.
Routing and sawing equipment
must be mechanical and power driven and capable of following the path of the
crack and widening the crack to a desired dimension without causing spalling or
damage to the adjacent pavement. Saw
blades must be diamond and 8 inches or less in diameter.
The pavement surface must be
dry (no visible moisture of any kind) and at least 45 °F (7 °C).
The Engineer determines the
cracks to be sealed.
If routing is required for
cracks of less than 3/4 inch wide, rout cracks to an opening 3/4 inch wide by 1
inch deep. This is the reservoir for the
joint sealant
If sawing is required, saw
cracks to 3/4 to 7/8 inch wide by 7/8 to 1 inch deep. The slivers of asphalt concrete left behind
that are less than 1 inch wide along the sides of the crack must be
removed. The Contractor can use hand
tools or a light weight chipping hammer. Before sealing the crack, it must be
sandblasted to remove contaminants and to provide a rough face so the sealant
adheres to the walls of the crack. If
the crack below the saw cut is greater than 3/8 inches, a backer rod has to be
pushed into the crack to form a bottom.
All cracks must be cleaned
using an approved method, including water blasting and air blasting. All dust, dirt, debris, moisture, and
vegetation must be removed from the crack.
The prepared crack must be kept clean and dry prior to sealing.
Determine the proper
proportion of fiber and binder to blend by using weigh tickets. Check for thorough mixing. Check the sealant temperature against the
manufacturer’s recommendation and do not let it exceed this temperature. Be sure the temperature of Type III sealant
does not exceed 295 °F (146 °C) at any time.
Fill cracks within 250 feet
(76 m) of the cleaning operation.
Seal cracks that are wide
enough to allow injection of the sealant.
Tight cracks less than 1/4 inch wide are to be sealed only if they are
raveling or spalling. Do not seal cracks
greater than 1 inch wide. Do not seal
spalls and cavities greater than 4 inches wide.
For Type I and IV sealants,
fill the entire crack reservoir from the bottom to about 1/16 inch above the
pavement surface. The surface must be
scraped immediately with a V-shaped or U-shaped squeegee to smooth the sealant
at the surface. The band that remains on
the surface after smoothing must be less than 2 inches wide. Wider bands must be rejected.
For Type II and Type III
sealant, the width of the band should be 2 to 4 inches, but never over 4
inches. Do not accept the work if the
band is too wide and/or the thickness of the sealant on the pavement surface is
more than 3/16 inches (5mm).
Do not allow traffic on fresh
sealant until it has cured and will no long pick up and track under
traffic. The Engineer may allow the use
of an anti-tracking material if traffic must use the roadway.
Crack sealing is measured by the
number of pounds of hot applied crack sealant in place and accepted.
1. Document that the materials are on an approved list,
have certified test data, and/or have been sampled as required.
2. Document type of sealant used (Type I, Type II, Type
III, Type IV) and mixing methods.
3. Document the proper crack preparation procedures,
including routing, sawing, and cleaning.
4. Document pavement conditions and air temperature.
5. Document when the pavement is opened to traffic and
any observations regarding sealant pick-up or tracking. Document and determine
weight of sealant for pay. Use weight
tickets only.