561.01 Description
This work involves milling of deck concrete using hydrodemolition or mechanical scarification.
561.02 Reserved
561.03 Construction Requirements
561.03.1 Submittals
Submit for approval the following:
1.A written plan detailing the methods, materials, equipment, and personnel to be used.
2.The method and materials used to contain, collect, and dispose of all debris generated by the removal, cleaning, and surface preparation process. Ensure adequate capacity to handle the amount of wastewater generated. Do not begin concrete removal until receiving approval.
561.03.2 Equipment
A.Hydrodemolition. Use a self-propelled hydrodemolition machine with high-pressure water jets capable of removing concrete to the removal depth shown in the contract. Use equipment of sufficient capacity and size to remove rust and concrete from the reinforcing steel. The equipment must have means to control the removal depth to within a tolerance of ⅜-inch (10 mm) above or below the plan depth. The equipment must have controls adequate to vary the water pressure, traverse and progression of the nozzle, oscillation or rotation of the nozzle head and the distance between the nozzle and the concrete surface. Provide accurate working pressure gauges at pumps and at the hydrodemolition unit.
B.Scarification. Use self-propelled mechanical scarifying equipment capable of removing ¼-inch (6 mm) depth minimum across the cutting path in one pass.
561.03.3 Procedures
A.Hydrodemolition. Mechanical scarification equipment may be used in conjunction with hydrodemolition to remove the portion of the deck above the top mat of reinforcement. If the milling equipment snags reinforcing steel, adjust the depth of removal to prevent further snagging. Remove the remaining concrete to the specified depth using hydrodemolition. Before beginning hydrodemolition, configure the hydrodemolition unit by adjusting water pressure, nozzle size and angle, nozzle travel speed and unit travel speed to remove sound concrete to the plan depth. Record all the settings and submit them to the Project Manager. During hydrodemolition, verify the removal depth every 30 feet (10 m) along the length of the deck and along the width of the hydrodemolition path. Record the settings at each of these points and submit them to the Project Manager. Use only potable water for hydrodemolition. Do not use stream or lake water. Plug all deck drains. Install dams of clean, washed aggregate, hay bales, sandbags, or other materials as needed to strain and to direct the flow of runoff. Provide and use settlement basins, if necessary, to produce visibly clear water before disposal. Do not allow wastewater or waste-cement slurry to run across active travel lanes. Obtain necessary permits before beginning the work and comply with applicable water quality regulations 561 – BRIDGE DECK MILLING 2020 EDITION V5.1 561-2 when disposing of the wastewater. Protect all adjacent areas and the traveling public from flying debris during removal operations.
B.Mechanical Scarification. Scarify the deck to the depth indicated in the contract. If the equipment snags reinforcing steel, stop work immediately and notify the Project Manager. Remove concrete, in areas designated for removal that milling equipment cannot reach, with chipping hammers no larger than a nominal 15-pound (7 kg) class or other equipment as approved by the project manager. This work is measured and paid for as Bridge Deck Milling. Thoroughly clean the deck of all aggregate, paste, residue, oil, and any other substance that may interfere with the repair or overlay concrete. Use cleaning methods that do not damage remaining concrete, reinforcing steel, or that cause debonding of remaining concrete and reinforcing steel. Keep heavy loads off of reinforcing steel left unsupported by concrete due to concrete removal.
561.04 Method of Measurement
Bridge deck milling is measured by the square yard (m
2.of deck surface removed. No measurement will be made for mechanical scarification used in conjunction with hydro milling. Include costs associated with mechanical scarification used in conjunction with hydro milling in the unit price bid for Bridge Deck Milling.
561.05 Basis of Payment
Payment for the completed and accepted work is made under the following: Pay Item Pay Unit Bridge Deck Milling Square Yard (m2)
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Source: Standard Specifications for Road and Bridge Construction, 2020 (v5.1) Edition. Pages 383–384 of 611. View official source ↗