Item 321 Cracking and Seating Existing Plain Concrete Pavement

Description (321.01)

Equipment (321.02)

Construction Details (321.03)

Documentation Requirements 321 Cracking and Seating Existing Plain Concrete Pavement

 

Description (321.01)

This work consists of breaking up an existing non-reinforced concrete pavement using a cracking and seating method to provide a stable base for the placement of new asphalt concrete pavement.

 

Equipment (321.02)

The Contractor must use equipment that is capable of producing the desired crack pattern without extensive spalling or excessive shattering. Extensive spalling is considered at depths of greater than 1-1/4 inches.

Whip hammers cannot be used.

The Contractor must use a 50 ton pneumatic tire roller that also conforms to the requirements of 204.06 (Proof Rolling) to seat the cracked concrete slabs. Additionally pneumatic tire towing equipment is required to move the roller forward and backward along predetermined lines. The Contractor shall provide information to verify the roller meets the specification requirements.

 

Construction Details (321.03)

The Contractor should provide positive provisions in addition to 107.07 to contain any flying debris during cracking operation.

The contractor must demonstrate to the Engineer the ability of the selected equipment and procedure to produce the desired crack pattern by cracking at least three, but no more than five existing concrete slabs. The Contractor shall furnish and apply water to dampen the cracked concrete to enhance visual determination of the crack pattern during the test section process. The contractor must make adjustments to the energy or striking pattern to maintain the crack pattern desired.

The Contractor must provide a crack pattern of 4 feet by 4 feet (1.2 m X 1.02 m) segments.

There may be instances where the existing slab is already cracked into segments by age and traffic. In these cases the Contractor must further crack the slabs to obtain maximum 5 feet and minimum 3 feet dimensions, both transversely and longitudinally.

The breaking equipment shall not be allowed to affect slabs within 1 foot of another break line, a joint, or the edge of the concrete slab.

 

Once a day (minimum) the Contractor must apply water to a check section to allow verification of a satisfactory crack pattern. When the crack pattern differs from required, the Contractor must make adjustments to the operation to bring the crack pattern into compliance.

The Contractor must roll the cracked pavement until the all of the concrete pieces are seated with at least two roller coverages. The seated pieces cannot rock or move after seating.

The Engineer will determine the maximum number of coverages of the roller on the test section to ensure proper seating of segments without damage to the concrete.

Before placing asphalt concrete the Contractor must remove all loose pieces of concrete that are not fully seated. All voids must be repaired by applying 407 tack coat, filling with asphalt concrete and compacting, as directed by the Engineer,

Traffic is not allowed on the cracked concrete before the initial asphalt concrete base and the intermediate courses are in place.

 

Documentation Requirements - 321 Cracking and Seating Existing Plain Concrete Pavement

1.        Document that equipment being used meets the specifications.

2.        Document the location and crack pattern obtained from the test section. Include any additional test sections and results.

3.        Document where cracking and seating is being performed (station to station), segment sizes obtained, roller coverages, addition of tack and asphalt to fill voids, and any other observations or issues during the operation.

4.        Measure the width of the actual existing pavement and the length along the centerline of each roadway and calculate square yards for payment.

5.        Document using form CA-D-3A or other approved form(s).