320 Rubblize and Roll

Description (320.01)

Materials (320.03)

Equipment (320.03)

Construction Details (320.04)

Documentation Requirements – 320 Rubblize and Roll


Description (320.01)

This work consists of breaking up existing rigid concrete pavement using a rubblize and roll method to provide a base material for the placement of new asphalt concrete pavement.


Materials (320.03)

Filler material may be needed to correct grade after the concrete pavement has been rubblized.  The contractor must furnish materials conforming to Item 304 to fill depressions 1 inch (25 mm) or greater in depth.


Equipment (320.03)

The contractor must use a self-contained, self-propelled unit of either the resonant frequency type or the multiple head breaker type for rubblizing the exposed concrete pavement.  There are specific equipment requirements for each type of breaker.  The Contractor must provide documentation showing that the proposed equipment meets those requirements.  Refer to C&MS 320.03 for specific details.

A vibratory roller is required and must have a total weight of at least 10 tons.  The Contractor must provide documentation for the roller if needed by the project to verify total weight.


Construction Details (320.04)

Saw Cutting

The Contractor must make a full depth saw cut to cut load transfer devices at existing joints on ramps or on the mainline pavement where the rubblizing abuts concrete pavement or approach slabs that are to remain in place permanently or temporarily for maintenance of traffic.

Test Section

The Contractor is required to rubblize a test section before beginning full scale operations.  The Engineer will designate the test section area.  The Contractor will rubblize the test section per the specification requirements.  At the direction of the Engineer, the Contractor will excavate a test pit to check the particle sizes of the rubblized concrete throughout the depth of the slab.   Based on the Engineer’s determination the rubblizing operation may proceed or additional test sections and test pits may be required to obtain the required particle sizes. 

The test pit can be refilled using the excavated material and additional 304 aggregate as needed to bring the final surface to the required grade.  The test pit can be rolled at the completion of the test section or later during full operation.

The Engineer may require additional test pits as necessary, throughout the rubblizing operation.

Control and Operating Speed

The Contractor is required to adjust the speed of the rubblizing operation to maintain the correct particle sizes.  If the Contractor is not consistently obtaining the specified particle sizes, the Engineer may require another test section, test pit, or additional passes to ensure compliance.  The correct particle size is of critical importance to obtaining a suitable base material.

Proper Particle Size

Particles sizes should range from sand sized to pieces not exceeding 6 inches (150 mm) in their largest dimension.  The majority being a nominal 1 to 2 inches (25 to 50 mm) in size.

Reduce the portion of the concrete slab above the reinforcing steel to 1 to 2 inches (25 to 50 mm) in size.

Filling & Compacting

Leave steel reinforcement in place in the rubblized pavement.  Reinforcing steel may rise to the surface during either the rubblizing or rolling operations. However cut off any exposed steel reinforcement to below the surface and remove it from the site.   

The rubblized pavement must be compacted with two passes of the vibratory roller operated in the vibratory mode and at a speed not to exceed 6 feet (1.8 m) per second. 

Depressions 1 inch (25 mm) or more in depth below the immediate surrounding surface, that form as a result of rubblizing, compaction, or steel reinforcement removal, must be filled with filler aggregate conforming to Item 304.

Excess filler material must be leveled off such that is level with the surrounding area.  Compact filled depressions with the same roller and compactive effort previously described.


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

The Contractor must structure operations such that not more than 48 hours elapse between rubblizing the pavement and placing the initial asphalt concrete course.  In the event of rain during the 48 hour period, the Engineer may waive this time limitation to allow sufficient time for the rubblized pavement to dry to the Engineer’s satisfaction. 

If the Engineer waives the time limitation, cease rubblizing the pavement until the Engineer allows paving to resume.

Method of Measurement (320.05)

The Engineer will measure Rubblize and Roll by the number of square yards (square meters). 

The Engineer will use the actual width of the existing concrete pavement and will measure the length along the centerline of each roadway or ramp.

The Engineer will measure the Filler Aggregate by the number of cubic yards (cubic meters) furnished, placed, and compacted.


Documentation Requirements - 320 Rubblize and Roll

1.        Document that equipment being used meets the specifications.

2.        Document the location and particle size determination for the test section.  Include any additional test sections and results.

3.        Document where rubblizing is being performed (station to station), particle sizes obtained, cutting of reinforcing steel, addition of filler aggregate, roller speed and passes, 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.        Measure the filler aggregate and calculate the number of cubic yards placed and compacted.

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