734Rubblizing Portland Cement Concrete Pavement

734.01 DESCRIPTION. Rubblize existing reinforced or non-reinforced

portland cement concrete pavement using a pavement-fracturing machine capable of delivering sufficient energy to rubblize the pavement full-depth in a manner that fractures the concrete slab into smaller pieces that eliminates slab action without damaging the subgrade. Thoroughly compact and seat the rubblized pavement with appropriate equipment as outlined in this specification. Either the resonant frequency breaker (Method 1) or the multihead breaker (Method 2) process may be utilized to rubblize and seat the pavement. Use only one of the methods (Method 1 or Method 2) on the project. When using Method 2 on concrete pavements with thickness greater than 11 inches, the contractor may use a guillotine -breaking device with the engineer’s approval, if pre-fracturing of the pavement is necessary to achieve rubblization size requirements without damage to the subgrade. Perform t he work in accordance with the lines, grades, and typical sections shown on the plans and as outlined in this specification.

734.02 Equipment.

734.02.1 Method 1 (Resonant Frequency Breaker Process):

734.02.1 1 Resonant Frequency Breaker Machine: Use a

self-contained, self-propelled, resonant frequency breaker for rubblizing existing pavement that is capable of producing 2000 pound force blows at a rate of not less than 44 cycles per second with an amplitude of less than 1 inch.

734.02.1 2 Resonant Frequency Breaker Seating

Equipment:

734.02.1 2.1 Steel-Wheel Vibratory Roller: Use a steel-

wheel vibratory roller having a gross weight of not less than 10 tons, operated in the vibrating mode, to compact the rubblized pavement.

734.02.1 2.2 Pneumatic-Tired Roller: Use a pneumatic-

tired roller as specified in 503.16.3 to compact the rubblized pavement.

734.02.2 Method 2 (Multihead Breaker Process):

734.02.2 1 Multihead Breaker Machine: Use a multihead

breaker that is a rubber-tired, self-propelled unit, which uses 12 to 16 hammers with weights ranging from 1,200 to 2,000 pounds mounted laterally in pairs with half the hammers in a forward row and the remainder diagonally offset in a rear row so that there is continuous breakage from side to side. Each hammer shall have one continuous strike bar whose width varies from 1 to 2 inches. Each pair of hammers is attached to a hydraulic lift cylinder, which operates as an independent unit, and cycles at a rate of 30 to 35 impacts per minute. It shall be capable of rubblizing up to 13 feet in width of pavement in one pass.

734.02.2 2 Multihead Breaker Seating Equipment:

734.02.2 2.1 Z-Grid Roller: Use a modified vibratory steel-

wheel roller with a "Z" grid pattern on the drum face. The roller shall have a gross weight of at least 10 tons, and operate in the vibratory mode, to settle and seat the rubblized pavement.

734.02.2 2.2 Steel-Wheel Vibratory Roller: Use a steel-

wheel vibratory roller having a gross weight of not less than 10 tons, operated in the vibrating mode, to compact the rubblized pavement.

734.02.2 2.3 Pneumatic-Tired Roller: Use a pneumatic-

tired roller as specified in 503.16.3 to compact the rubblized pavement.

734.03 Construction Requirements.

734.03.1 Preparation Prior to Rubblization:

734.03.1 1 Drainage System Installation: Prior to

rubblization operations, install drainage systems as shown on the plans. Ensure that drainage systems are properly functioning for a minimum of two weeks prior to rubblization.

734.03.1 2 Removal of Existing Asphalt Surfaces: Remove

existing asphalt concrete overlays and patches from the PCC pavement surfaces prior to rubblization. Existing full-depth asphalt patches shall remain in place, unless directed for removal and replacement by the engineer.

734.03.1 3 Saw-Cut Joints: Make new full-depth saw-cuts

along existing joints on all pavement edges where rubblized PCC is adjacent to pavement that will remain in place. Sever all load transfer devices between the planned rubblization and PCC pavement remaining in place.

734.03.1 4 Shouldering: Complete shoulder adjustments and/or

any pavement widening up to the elevation of the existing pavement grade prior to beginning the rubblization operations. These areas can be used to support the rubblization machines while the existing PCC pavement is being rubblized.

734.03.2 Test Strip and Test Pit to Establish Procedure:

734.03.2 1 Test Strip: Before the rubblization process begins,

the engineer will designate a test section of at least 150 feet by 12 feet. Rubblize the test section using varying degrees of energy and/or various striking heights until a procedure is established that will rubblize the pavement as outlined herein. On projects that have a transition to a bridge or to an overpass, make the test pit in the transition where the material will be totally removed.

734.03.2 2 Test Pit: In the middle of the test strip, excavate a 4-

foot square test pit at a location selected by the engineer, to determine that the breaker is producing rubblized pieces of the specified sizes as outlined in these specifications. Check the rubblized particle sizes throughout the entire depth of the pavement. Remove the test pit material from the project and fill the hole using coarse aggregate material as specified in 1003.03. Place and properly compact the replacement material to the satisfaction of the engineer. The engineer and the contractor shall mutually agree upon the rubblization procedure based on the performance criteria contained herein. Use the established procedure to rubblize the remainder of the pavement. Continuously monitor the rubblization operation, and make minor adjustments in the striking pattern, striking energy, number of passes, and other factors necessary to continually achieve acceptable rubblization throughout the project. Inform the engineer of any ma jor adjustments that may be required in the process to provide rubblized pavement that conforms to the specification requirements. Additional test pits may be required by the engineer to confirm that the PCC pavement is adequately rubblized.

734.03.3 Rubblization Criteria:

734.03.3 1 Method 1 (Resonant Frequency Breaker):

Compact the complete width of the rubblized pavement surface with the vibratory steel-wheel roller and pneumatic-tired roller in the following sequence as a minimum. The engineer will determine if more passes are necessary.

734.03.3 2 Method 2 (Multihead Breaker): Compact the

complete width of the rubblized pavement surface with the vibratory Z-grid roller, vibratory steel-wheel roller, and pneumatic-tired roller in the following sequence as a minimum. The engineer will determine if more passes are necessary.

734.03.4 Reinforced Portland Cement Concrete Pavement:

Debond the reinforcing steel from the concrete and leave in place. If any steel is protruding from the surface, cut the steel below the surface and remove.

734.03.5 General Rubblization Procedures: Rubblize in partial

widths when necessary to maintain traffic as shown in the contract documents. When the rubblization process is adjacent to in-service pavement, take measures to prevent debris from entering the in-service pavement. In areas where the pavement is to be overlayed prior to completion of the rubblization, extend the initial rubblization a minimum of 6 inches beyond the width of the pavement to be overlayed. For the resonant frequency breaker process, begin rubblizing at a free edge or previously broken edge and progress toward the opposite shoulder or longitudinal centerline of the pavement. Continuous coverage of the entire pavement surface, overlapped if necessary to achieve adequate rubblization with the breaking shoe, will be required. Additional passes of either rubblization device may b e required to meet the particle sizes outlined in this specification as directed by the engineer.

734.03.6 Dust Control: Minimize the dispersion of dust from the

rubblization operation until the rubblized surface is overlayed with asphalt concrete. Provide a water truck, operator, and all water necessary for dust- control purposes. Do not apply excessive water to the rubblized surface. Dust control is incidental to the rubblization process and will not be paid for separately. Dust-mitigation measures must be acceptable to the engineer.

734.03.7 Damage to Base, Underlying Structures, and Other

Facilities: Operate the rubblization machine and rollers in a manner that will avoid damaging the base, underlying structures, utilities, drainage facilities, bridge approach slabs, bridge decks, and other facilities on the project. If any damage occurs, immediately cease operations, notify the engineer, and repair the damage as directed. Make repairs in a timely manner at the contractor’s expense.

734.03.8 Unstable Area Patching: If unstable areas occur because

of expansion of the existing concrete pavement, remove the unstable areas to a maximum length of 4 feet by 12 feet in width and replace with full- depth asphalt concrete patching in accordance with Section 510 as directed. Patching procedures shall conform to the standard specifications, and shall be completed prior to placing the asphalt concrete overlay. Patch areas of poor subgrade suppo rt that are identified during the rubblization and seating process as directed. Remove the rubblized pavement, base course, and subgrade material from unstable areas. Replace the material with full depth asphalt concrete patches in accordance with Section 510 as directed.

734.03.9 Progress of the Work: Unless otherwise specified, no

more than 48 hours shall elapse between rubblizing the pavement and the placement of the asphalt concrete overlay. A minimum of 4 inches of asphalt concrete is required before traffic is allowed on the on the rubblized pavement. If rain occurs between these operations, this time limitation may be waived to allow sufficient time for the rubblized pavement to dry to the satisfaction of the engineer. Except at restricted crossover and ramp crossings, do not allow traffic on the rubblized pavement before the initial asphalt concrete base and leveling courses, if required, are in place. Immediate ly remove rubblized material dislodged by construction traffic from the roadway in front of the paver.

734.04 MEASUREMENT. Rubblizing portland cement concrete

pavement will be measured by the square yard. The width will be the nominal width of the existing pavement, and the length will be measured along the centerline of each roadway or ramp.

734.05 PAYMENT. Payment for rubblizing portland cement concrete

pavement will be made at the contract unit price per square yard, which includes furnishing all materials, labor, equipment, and incidentals necessary to complete the work. Payment will be made under: Item No. Pay Item Pay Unit 734-01 Rubblizing Portland Cement Concrete Pavement (Resonant Frequency Breaker) Square Yard 734-02 Rubblizing Portland Cement Concrete Pavement (Multihead Breaker) Square Yard

Rubblizing Portland Cement Concrete Pavement in other states

• Kansas 839 · Rubblizing Portland Cement Concrete Pavement
• Michigan 304 · Rubblizing Portland Cement Concrete Pavement
• Oklahoma 433 · Rubblizing Portland Cement Concrete Pavement