258.01 Description
258.02 Materials
258.03 Equipment
258.04 Construction
258.05 Method of Measurement
258.06 Basis of Payment
258.01 Description. This work consists of sawing slots across transverse cracks, cleaning
the slot, injecting caulking filler, placing a dowel in the slot, filling the
slot with a patching material, and establishing a joint by saw cut.
Furnish a
one part silicone sealant which does not require a primer for bond to concrete
and conforms to the following Table:
|
Properties |
Requirements |
|
Flow, ASTM D5893 |
0.3 inches(7.6 mm) maximum |
|
Extrusion Rate, C1183 method A |
75-350 grams/minute |
|
Tack free time @ 77° F ± 3°F (25°C ±2°C) –ASTM C679 |
20-90 minutes |
|
Specific Gravity - ASTM D 792, Method A |
1.010-1.515 |
|
Durometer Hardness - Shore A, cured 7 days @ 77°F± 3° F (25°C ± 2°C) and 45-55% R.H.; ASTM D 2240 |
10-25 at 0°F (-18°C) |
|
Tensile Stress -@ 150% elongation, 7 day cure @ 77°F ± 3°F (25°C ±2°C) and 45-55% R.H.; ASTM D 412, Die C |
45 psi (310 kPa) maximum |
|
Elongation - 7 day cure @ 77° F ± 3°F (25°C ± 2°C) and 45-55% R.H.; ASTM D 412, Die C. |
800% minimum |
|
Bond to Concrete Mortar: Briquets - Air cured 12 days @ 77° F ± 3°F (25°C ± 2°C);** |
50 psi (345 kPa) minimum |
|
Movement Capability and Adhesion *** |
Extend 100% and compress 50%; No adhesive or cohesive failure after 10 cycles at 0°F (-18°C) |
|
Shelf Life |
9 months from date of shipment from manufacturer |
|
**Bond to Concrete Mortar: Briquets molded in accordance with AASHTO T 132 sawed in half and bonded with a thin section of sealant and tested in accordance with AASHTO T 132. Briquets will be dried to constant weight in oven at 212° F ± 9°F (100°C ± 5°C). |
|
|
***Movement Capability and Adhesion: Prepare1-inch x 2-inch x 3-inch(25 mm x 50 mm x 75 mm ) concrete blocks in accordance with ASTM C 719. A sawed face will be used for bond surface. Seal 2 inches (50 mm) of block leaving 1/2 inch (13 mm) on each end of specimen unsealed. The depth of sealant will be 3/8 inch (10 mm) and the width 1/2 inch (13 mm). Subject sealant to movement in accordance with ASTM C 719. The magnitude of the movement will be as specified, and the rate of extension or compression will be 1/8 inch (3.2 mm) per hour. |
|
Furnish
materials conforming to:
Aggregate................................................................ 703.02.
A.3
Curing material......................................... 705.07, Type 2.
Dowel bars.............................................. 709.13 or 705.01
Dowel bar chairs............... 709.14 or non-metallic material
Preformed filler........................................................ 705.03
Patching material. Must meet the performance requirements of ASTM C928, Table 1, R3 concrete material with the following exceptions and additions:
.... Final Set Time (ASTM C403)..... 25 minutes minimum
.... Length Change (ASTM C157)
.... @ 4 days.......................................... ± 0.13% maximum
.... Freeze Thaw Durability Factor (ASTM C666) Procedure A @ 300 cycles or Procedure B @ 350 cycles,
.... Durability Factor:................................... 90% minimum
Furnish patching material according to the Departments
Qualified Products List (QPL)
Mix prepackaged materials that contain all
aggregates needed to produce the desired concrete as specified by the
manufacturer. For bagged cementitious
materials that need additional aggregates, grade the aggregate according to the
patching material manufacturer’s recommendation except ensure that 100% passes
the 1/2 -inch (12.5 mm) sieve and a minimum of 85 percent, by weight, passes
the 3/8-inch (9.5 mm) sieve.
258.03 Equipment. Furnish equipment to create slots that has a
power driven gang type assembly, consisting of diamond blade saws, capable of
sawing a minimum of three slots at one time to the required dimensions, without
damage to the surrounding pavement.
Furnish
jack hammers weighing less than 30 pounds (13.6 kg).
Furnish
abrasive blast equipment capable of removing the saw slurry or other foreign
material from the exposed surfaces leaving a clean, newly exposed concrete
surface free of spalls, latence, and all contaminants detrimental to achieving
an adequate bond. Ensure water blasting
with abrasives in the water is 10,000 psi (690 bar) or less.
258.04 Construction. The
Engineer will
locate and mark cracks to be retrofitted.
Provide the Engineer with aerosol spray paint to mark the cracks to be
retrofit.
Cut two and
one-half inch (65 mm) wide slots into the pavement to a depth which places the
center of the dowel at mid-depth in the concrete slab. Make the slots parallel to the centerline of
the pavement. Make multiple saw cuts
parallel to the centerline if necessary to properly remove material from the
slot and to provide a level surface for the feet of the dowel bar chairs. Cut three slots, on one foot centers (0.3 m),
in each wheel path, as shown in the standard drawings.
Do not
allow traffic across the crack once the concrete has been removed from the
slots until all six retrofit dowel bars are in place, cured and completed. Do not allow the tires of construction
vehicles to travel on slots where concrete has been removed.
Clean the
edge of the slots by approved blast methods to produce a rough surface. Insure any blasting operation does not damage
the surrounding pavement. Do not begin
abrasive blasting operations until implementing reasonably available
engineering controls to limit fugitive dust that are acceptable to the Engineer.
Conform to state, regional, and local government agency requirements
regarding control of dust generated by the blasting operation.
Caulk
cracks at the bottom and sides of the slot with an approved silicone sealant in
order to prevent any grout from entering the crack. Apply the sealant with a pressure applicator
that forces it into the crack.
Place a 1/2
inch (13 mm) thick preformed filler board to maintain the crack, as shown in
the plan details. Ensure the filler
board fits tight around the dowel and to the bottom and edges of the slot. Maintain the filler board in a vertical
position and tight to all edges during placement of the patching material. Ensure the filler board extends from the
bottom of the slot to no more than 1-1/2 inches (38 mm) from the surface of the
pavement. If for any reason the filler board shifts during placement of the
patching material, redo the dowel bar retrofit at no expense to the Department.
Ensure the
dowel bar chair firmly holds the bar centered in the slot. Obtain the Engineer’s approval before using any dowel bar
chairs. The Engineer will reject any
chair design that may allow movement of the bar during the placement of grout.
Use dowel
bars 1-1/2 inches (38 mm) in diameter
and 18 inches (460 mm) long. Center the
filler board on the dowel. Coat the dowel bars with a thin layer of oil or
other bond-breaking material just prior to installation in the slot. Place an expansion cap on each end of the
dowels prior to installation. Ensure the
expansion caps are tight fitting and made of non-metallic material which will
allow 1/4 inch (6 mm) movement at each end
of the dowel.
Use two
chairs to firmly hold the dowel bar in the slot during placement of the
patching material. Furnish chairs that
are a nominal 2-1/2 inch (65 mm) wide
and center the dowel bar across the crack.
Ensure the bar varies no more than 1/4
inch (6 mm) from parallel to the pavement surface and the centerline of
the pavement. Just prior to placement of
the patching material, make one or more passes of an air blast to provide a
dust-free, clean slot to insure an adequate bond of the patching material.
Mix, place,
and cure the patching material in accordance with the manufacturer’s
recommendations. Consolidate the
patching material using a vibrator approved by the Engineer. Place
the patching material in the slot and finish to produce a smooth, even
surface. Cut a 1-1/2 inch (38 mm) deep
by 1/4 inch (6 mm) wide saw cut, using a hand pushed single blade saw, to
re-establish the crack. Make the saw cut
within four hours of placing the patching material.
Repair any
damage to the pavement due to the Contractor’s operation at no expense to the Department.
Cure the
patching material for a minimum of four hours before placing any vehicle loads
on the repair, or as directed by the Engineer.
258.05 Method of
Measurement. The Department will measure the quantity of
Retrofit Dowel Bars by the actual number in the complete and accepted work.
258.06 Basis of
Payment. Payment is full compensation for furnishing all materials including
paint; sawing and cleaning the slots; installing dowel chairs, dowels, bond
breaker material, dowel bar end caps, sealant/caulking material, filler
material, and patching material; and re-establishing the crack.
The
Department will not pay for additional work or materials required due to
shifting of the filler board.
The
Department will not pay for any additional work to repair damage to the
pavement caused by the Contractor.
The
Department will pay for accepted quantities at the contract unit price as
follows:
Item unit Description
258 Each Retrofit Dowel Bar