SECTION 02581 PAV 2008.doc

SECTION 02581

SAWING AND SEALING JOINTS IN BITUMINOUS CONCRETE OVERLAY

1. REFERENCES:

New Jersey State Highway Department (NJSHD)

Specifications for Road and Bridge

Construction

1. DESCRIPTION:

1.2 This work shall consist of locating, referencing, constructing and sealing saw cuts in bituminous concrete overlays constructed over existing Portland cement pavement or previously overlaid Portland cement concrete pavement.

2. MATERIALS:

2.1 Joint sealer shall be a hot poured sealant conforming to Subsection 908.2. NJSHD Specifications for Road and Bridge Construction

3. EQUIPMENT:

3.1 Saws.

3.1.1 Sawing equipment shall conform to the requirements of Subsection 405.03, NJSHD Specifications for Road and Bridge Construction, except that dry diamond edge blades or abrasive wheels shall be permitted, providing that the saw cut does not result in excessive spalling at the sawed edges. Dry saws shall be equipped with an approved dust collection system to prevent airborne residue from escaping in the atmosphere. The wet sawing operation shall provide a means for removing the wet slurry from the pavement and joint wall. The blades shall be of such size and configuration that the desired dimensions of the saw cut are achieved in one pass. When approved, the T-shaped cut shall be made in two stages . When the two stage system is permitted, the second sawcut (to complete the specified joint shape) shall be made on the same work day as the first cut.

4. SEALING:

4.1 Sealing equipment shall consist of a kettle or melter and applicator wand. The melter shall be constructed as double boiler with the space between the inner and outer shells filled with oil or other heat transfer medium. The melter shall include positive temperature control, mechanical agitation, re-circulation pumps and thermometers for continuous reading for the temperature of both the sealing compound and the heat transfer medium. The applicator wand shall be heated or insulated to maintain the pouring temperature of the sealant during the placing operation. Pouring pots or similar devices shall not be used to fill sawed joints.

5. CONSTRUCTION REQUIREMENTS:

5.1 An accurate system for locating and referencing proposed saw cuts shall be established and maintained throughout duration of the work. The location of the saw cuts shall be directly over the existing concrete pavement joints and cracks and shall be accurately established by a method employing pins and string line or other positive referencing system. The saw cut locations shall be established prior to paving. Details of method for establishing the location of the saw cuts shall be submitted for approval at least two weeks prior to the start of paving.

5.2 Existing transverse joints that are offset at the longitudinal joint by more than one inch, measured between the centers of the joints, require separate saw cuts terminating at the longitudinal joint. Full depth, full width bituminous concrete replacement of an underlying concrete slab shall have separate saw cuts in the overlay directly over the bituminous concrete/slab interface. Overlays shall be saw cut over transverse cracks that are reasonably straight, at least 1/8 inch wide and extend one full lane width.

5.3 Saw cuts shall be made in a straight line. When a saw cut is to be made over a crack in the existing concrete pavement, the saw cut shall be made over the approximate centerline of the crack.

5.4 The dimensions of the saw cut shall be as follows:

a. For overlays whose total thickness is 2” or less, the saw cut shall be 3/8” to 1/2” wide by 5/8” deep

b. For overlays whose total thickness is greater than 2” the saw cut shall be a “T” shaped cut consisting of the saw cut specified in (a) above plus a 1/8” wide saw cut at the center. The total depth of the saw cut shall be in accordance with the following:

Total thickness of Overlay Depth of Cut

More than 2” but less than 6” 2” +/- 1/4”

6” or greater 4” +/- 1/4

6. LIMITATIONS:

6.1 Saw cutting, cleaning and sealing shall be a continuous operation. If traffic is permitted on the overlay prior to sealing of the saw cuts, the saw cuts shall be blown clean prior to sealing. Any unsealed saw cuts damaged by traffic shall be re-sawed when sealing operations resume without any additional cost to the Government.

6.2 Saw cuts shall be made no earlier than one day following placement of the overlay and no later than five days after the placement of the overlay.

6.3 The transverse saw cut joints shall extend the full width of the traveled way and shall extend into the bituminous shoulder to a distance of 3 feet beyond the edge of the underlying Portland cement concrete pavement.

6.4 If cracks appear in a base course or bottom layer prior to placement of the top layer, such cracks shall be referenced and the top layer saw cut shall be made directly over the crack, rather than directly over the joint.

7. CLEANING:

7.1 Saw cuts shall be thoroughly cleaned with a water blast (50 PSI minimum) immediately aster sawing to remove any sawing slurry, dirt or deleterious matter remaining in the saw cut cavity. Saw cuts shall be blown with air to provide dry surfaces prior to sealing.

7.2 All sawing slurry from the wet sawing process shall be immediately flushed from the pavement surface.

8. SEALING:

8.1 A copy of the sealant manufacturer’s recommendations pertaining to the heating and application of the joint seal shall be submitted to the Contracting Officer’s Representative, at least two weeks prior to the start of work. The manufacturer’s recommendations shall be adhered to. The temperature of the sealer in the field application equipment shall not exceed the recommended safe heating temperature. Sealant material shall not be heated at the pouring temperature for more than six hours and shall not be reheated.

8.2 Saw cuts shall be sealed immediately after cleaning. The sealer shall fill the saw cuts such that after cooling, the level of the sealer is not more than 1/4 inch nor less than 1/8 inch below the surface. Care shall be taken in sealing so that saw cuts are not overfilled and their final appearance shall present a neat line. Sealant shall be track free prior to traffic. Sand, cement or other fine material shall not be spread on the sealed joint to allow early opening to traffic.

9. FABRIC INSTALLATION.

9.1 A surface treatment pavement overlay polypropylene fabric, weight 6 ounces per square yard, such as “Terra Tex OL” or equal shall be used.

9.2 Site preparation. Prior to applying the fabric, the existing surface must be cleaned of all dirt, water, oil or other foreign materials. Cracks larger than 1/4” in width must be filled with an elastic bituminous material. Potholes must be repaired by filling with hot mix.

10. TACK COAT APPLICATION:

10.1 An asphalt cement such as AC-10 or AC-20 is the recommended tack coat to be employed for this type of fabric. Under no circumstances should a “cut back” type tack coat be selected. The amount of residual tack coat applied normally lies between .15 and .25 gallons per square yard, with .22 gallons per square yard as the typical quantity. The spray width of the tack should be 6” greater than the fabric width.

11. FABRIC LAYDOWN:

11.1 The fabric should be put down while the tack coat is still soft for small applications or where no automated lay down equipment is available, the fabric can be placed directly on the pavement and rolled by hand onto the tack surface. The fabric is then broomed to remove small wrinkles and air pockets. Large wrinkles of 1/2” width or more must be slit and the pieces overlapped in the direction of paving. Additional tack is then applied along the joint. Where possible, the fabric should be rolled to improve surface contact.

12. ASPHALT APPLICATION.

12.1 Paving should begin immediately after fabric lay down. Some hot mix should be applied by hand at the beginning and the ending edge of the fabric to prevent pick-up or damage by the paver. In addition, the paver and the trucks must avoid making any quick stops, starts or sharp turns while on the fabric. The asphalt is applied using standard application techniques. The thickness of new asphalt should be determined by accepted design methods but should not be less than 1 inch compacted.

TYPICAL FABRIC PROPERTIES AND DESCRIPTION

Grab Tensile Strength 115 pounds

Grab Elongation 60%

Shrinkage from Asphalt 6%

Standard Roll Length 360 Feet

Standard Roll Width 12.5 Feet

Standard Roll Weight 145 pounds

13. METHOD OF MEASUREMENT AND PAYMENT. All measurements shall be in units as identified in the appropriate SLINS in the Unit Price Schedule. Measurements for preparing payments shall be taken jointly with the Government Representative. Payment for these items shall constitute full compensation for completed work including all labor and incidentals necessary to accomplish the work required by this section of the specifications.

END OF SECTION

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