SECTION 840 — DECK SURFACE CONCRETE REMOVAL BY HYDRODEMOLITION 800-193 — DECK SURFACE CONCRETE REMOVAL BY HYDRODEMOLITION
840.01 Description.
This work includes the removal of deteriorated concrete from reinforced concrete bridge deck surfaces using hydrodemolition methods, the provision of adequate containment measures under the bridge deck, the control and diversion of runoff during the hydrod emolition operations, disposal of all concrete and other materials removed by hydrodemolition, and all other incidentals as necessary to complete the work.
840.02 Equipment.
Remove the concrete by hydrodemolition equipment that produces a high-pressure water stream capable of removing concrete, asphalt, oil, dirt, concrete laitance, and rust from the exposed reinforcing bars by direct impact. Do not use rotary milling or mechanical abrading machines. Use hydrodemolition equipment that includes filtering and pumping units operating in conjunction with a remote-controlled robotic device and, if applicable, that can use river, stream, or lake water. Do not withdraw water from any body of water under the jurisdiction of the RI Department of Environmental Management (RIDEM) or the Coastal Resources Management Counc il (CRMC) unless authorized by a permit issued by the appropriate regulatory agency. Use hydrodemolition equipment that can produce a water jet through an orifice at a pressure of at least 17,000 psi. Ensure that the machine can move the jet transversely across the area and forward or backward so that the entire deck is exposed to the water jet. Use mechanical means to move the jet; do not manually move the water jet except at inaccessible areas such as proximity to the curb and temporary barriers or at bridge deck expansion joints. Use equipment that operates at a noise level of less than 90 decibels at a distance of 50 ft from either the powerpack unit or the remote robot. Controls. Ensure that the hydrodemolition equipment has sufficient controls to control and vary the following functions of the machine: • Water pressure • Angle and distance of the orifice relative to the deck surface • Limits of transverse and longitudinal movement of the orifice • Speed of the orifice in the transverse and longitudinal direction Submissions and Qualifications. Assume responsibility for any delay if the post-qualification criteria are not satisfied. Submit the required post-qualification information on the hydrodemolition operations for approval by the Engineer. The Contractor may submit more than one set of documentation. Adhere to the following requirements:
Part 800 — Bridge Structures August 2025
800-194 SECTION 840 — DECK SURFACE CONCRETE REMOVAL BY HYDRODEMOLITION
a.Minimum Requirements . Include the following post -qualification documentation at a minimum: ● The name and location of all projects completed, a brief description of the work performed, equipment specifications, estimated production rates, and references of personnel ● Specifications for all equipment to be used for the concrete removal, surface preparation, and clean-up operations ● Anticipated rate of production ● An inventory of all common spare parts and replacement accessories required for the equipment ● Number of personnel, machine operators, and supervisors, and their relevant experience ● Proposed method and sequencing of operation for all phases of the concrete removal and surface preparation operations Compliance with the post -qualification criteria applies regardless of the arrangements made by the Contractor to accomplish the hydrodemolition work. Ensure that Subcontractors meet the above post-qualification requirements. Shielding Requirement. Submit Shop Drawings showing details, design, and catalog cuts for the temporary protective shield system to the Engineer for approval consistent with Subsection 105.02. Ensure that the shield system will protect pedestrians, vehicle and/or railroad traffic, and utility infrastructure, and ensure that no material or debris associated with the hydrodemolition operation falls below the structure. Ensure that the system is designed for the anticipated weight of all material to be supported.
840.03 Construction Methods.
Concrete Removal. Adjust the hydrodemolition equipment so that the depth of concrete removed from areas of sound concrete is approximately ½ in. Where deteriorated concrete is encountered, the Engineer will establish the removal depth. Use the following trial test procedure to ensure that the correct amount of sound concrete is removed by the hydrodemolition machine:
1.The Engineer will locate and record the limits of a trial test of sound concrete approximately 30 sq ft in size.
2.An area of sound concrete is defined as an area free from chemical defects, delamination, spalling, and/or cracking. To locate and identify the area of sound concrete, test the deck
Part 800 — Bridge Structures August 2025
SECTION 840 — DECK SURFACE CONCRETE REMOVAL BY HYDRODEMOLITION 800-195 surface for soundness in the presence of the Engineer and following the removal of the asphalt wearing surface.
3.Perform chain dragging, tapping with a hammer, or other means of testing approved by the Engineer.
4.Advance the hydrodemolition machine over this area, and adjust the operating parameters to remove 2 in. of sound concrete within the test area. The Engineer will measure the depth of concrete removal.
5.If the adjustment is such that the machine is removing too much or too little concrete, calibrate the machine and repeat the above procedure as many times as necessary to achieve the required depth.
6.Perform one test for each stage of deck surface concrete removal. Ensure that the equipment is operated by qualified personnel certified by the equipment manufacturer. Submit the operator certification to the Engineer for approval before beginning the concrete removal operation. Ensure the availability of service personnel and an inventory of common wear parts and replacement accessories for the equipment to guarantee that the removal operation will not be interrupted for an extended period of time if an equipment breakdown occurs. Submit a list of operating parameters to be used for the hydrodemolition work to the Engineer before the commencement of concrete removal. Once the operating parameters are established by programming or calibration, do not change the parameters as the machine progresses across the bridge deck except to prevent unnecessary removal of sound concrete below the required minimum removal depth. If , after calibrating the hydrodemolition equipment and beginning production work in a specific area, insufficient removal of concrete is being obtained, recalibrate the equipment for that area to ensure removal of concrete to the specified depth. Remove any areas of the prepared surface that have been contaminated by oil or other materials detrimental to maintaining a good bond to the depth required. Perform the cleaning or removal at no additional cost to the Department, and assume responsibility for any resulting delays. Control of Debris and Water. Provide structurally adequate shields so that the water jet and broken concrete will not be a hazard to workers, traffic on adjacent lanes, or pedestrians and property below or adjacent to the bridge. Continually drain the water from the bridge, and ensur e that the excess water does not accumulate to avoid damaging the area below the bridge. Remove all debris immediately following the hydrodemolition operation by employing a vacuum recovery system to prevent rebonding to the remaining surface. Remove all debris that resettles or rebonds to the surface of the sound concrete. Avoid damage to the remaining sound concrete and reinforcing steel.
Part 800 — Bridge Structures August 2025
800-196 SECTION 840 — DECK SURFACE CONCRETE REMOVAL BY HYDRODEMOLITION Use methods for the control, maintenance, and disposal of hydrodemolition runoff that conform to SECTION 214. Ensure that the runoff control features are in place and operational before beginning concrete removal. Prevent runoff across traveled way, into bridge drainage devices, or into areas below or adjacent to the bridge, except for the containment basin. Reinforcing Steel. Following the hydrodemolition operation, inspect all exposed reinforcing steel to ensure that it has been cleaned of all rust and corrosive products, including oil, dirt, concrete fragments, laitance, loose scale, and other coatings that could destroy or inhibit the bond with the new concrete. Reclean exposed reinforcing steel not adequately cleaned by the initial hydrodemolition process. If the bars are deteriorated such that they have lost 25 percent or more of their original diameter, replace the steel as specified according to either the Contract or SECTION 818. When cleaned reinforcing steel is exposed for more than seven calendar days, protect the steel from contamination by the type of materials listed above. A light coating of rust can be expected to form on the reinforcing; this is not considered contamination. Concrete Placement. Conduct the placement and finishing of concrete for deck repairs and deck overlays as specified in SECTION 818.
840.04 Method of Measurement.
Deck Surface Concrete Removal by Hydrodemolition will be measured by the number of square feet of deck surface removed.
840.05 Basis of Payment.
The Department will pay for the completed and accepted quantities as follows. Pay Item Pay Unit Deck Surface Concrete Removal by Hydrodemolition SF The price constitutes full compensation for the removal of the bridge deck surface concrete to the limits shown i n the Contract, including all labor, equipment, tools, design and installation of protective shields, runoff diversion and incidentals necessary for proper completion of the work, complete and accepted. Supplemental steel reinforcement will be paid separately under SECTION 810. No additional payment will be made for the removal of deteriorated concrete in excess of 2 in. with the hydrodemolition equipment unless specified on the Plans or for any miscellaneous trim
Part 800 — Bridge Structures August 2025
SECTION 840 — DECK SURFACE CONCRETE REMOVAL BY HYDRODEMOLITION 800-197 work along the curb, temporary barriers, or on the deck, as required to fulfill the requirements of this Specification.
Referenced in this section
Get an email when 840 changes
Rhode Island revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.
Source: Standard Specifications for Road and Bridge Construction (Blue Book), 2022 (Aug 2025 compilation) Edition. Pages 562–566 of 951. View official source ↗