Article 1 — Description
Surface concrete bridge deck as specified to provide prepared substrate for concrete overlay or to remediate a finished surface.
Article 2 — Equipment
Use equipment within the maximum allowed legal load or provide analysis showing equipment will not overstress the bridge. Use machines equipped with dust control measures and shielding to prevent flying debris from leaving the work area.
2.1 Micro Milling . Use concrete milling equipment capable of maintaining constant depth of cut as specified.
Equip machine with automated debris collection system. Provide micro milling drum with tool spacing up to 1/4 in. Do not allow travel speed in feet per minute to exceed 2/3 of the drum revolutions per minute.
2.2 Hydro -Demolition . Use e quipment consisting of ultra- high pressure water jets (> 10,000 psi) capable of
removing concrete to depth specified. Provide machine that can be calibrated to remove an incremental depth of uniform strength concrete.
2.3 Shot Blasting . Use self -propelled shot blasting equipment using steel abrasive being propelled at the
concrete surface and equipped with a self -contained vacuum system to collect all removed debris.
2.4 Diamond Grinding. Use self -propelled diamond grinding equipment capable of removing concrete sur face
and producing corduroy -type texture. Provide machine equipped with dual longitudinal controls capable of operating on both sides automatically from any longitudinal grade reference and with cutting wheel containing 50–60 diamond blades per f oot. Minim ize dust escaping into environment by equipping machine with self -contained vacuum system to collect all debris removed.
2.5 Saw Grooving. Use sawing equipment capable of cutting grooves in completed bridge slabs and top slabs of direct traffic culverts. Provi de grooves that are 1/8–3/16 in. deep, nominally 1/8 in. wide , and spaced at
1 in. Use sawing equipment capable of cutting grooves in hardened concrete to within 18 in. of the barrier rail or curb.
Article 3 — Construction
Protect bridge joints, drains, and other appurtenances from surfacing operations. Following surfacing, clean the surface to remove all cuttings and debris. Dispose of all cuttings and debris pr operly . Use chipping tools and other smaller approved concrete surfacing equipment in small areas not accessible to the large surfacing equipment. Approval to begin work is not an endorsement of proposed equipment. If equipment fails to meet specification requirements, replacing equipment may be required. No additional time or compensation to adjust or replace equipment will be granted. Perform concrete bridge deck surfacing as specified in accordance with the following listed methods .
3.1 Micro Milling . Mill the existing deck to remove concrete to the depth specified. Provide a uniformly rough
surface with a chipped appearance suitable for bonding a concrete overlay. Scarify at locations shown on the 755 plans or as directed to the depths shown on the plans. Measure the depth from the level of the existing surface to the high points on the scarified surface. Ensure damage does not occur to the bridge slab reinforcing steel, armored joints, slab joints, drainage hardware, and other appurtenances. Stop milling operations if reinforcing steel is encountered. Proceed with further milling only when approved to do so. Establish and maintain independent grade control for concrete scarifying operations when appropriate or required. Use chipping tools to remove concrete in small areas not accessible to the mechanical scarifier.
3.2 Hydro -Demolition . Submit for approval a water disposal plan associated with the work. Follow all water
disposal requirements in conformance with federal, state, and local law. Temporarily plug all bridge drains near the area of work to prevent runoff result ing from the work from being released. Protect surrounding property and traffic from water spray and material dislodged. Remove plugs after completion of the work. Provide water for hydro- demolition that meets the requirements of Section 421.2.5., “Water,” Table 1. Provide remotely operated vacuum unit to reclaim water, debris, and concrete cuttings. Collect water, debris, and concrete cuttings in a separate unit located off the bridge deck. All equipment on bridge deck must be in accordance with Sections 7.16.2., “Construction Equipment Operating on St ructures,” and 7.16.3., “Loads on Structures.” Alternate reclamation equipment may be approved, provided a structural analysis, signed and sealed by a licensed professional engineer, is submitted that considers depth of removal and deterioration of structu ral elements. Demonstrate hydro- demolition on test areas as specified to calibrate machine to obtain concrete removal depth and finish as specified and as approved. At minimum, calibrate machine to remove all unsound concrete and sound concrete to the spec ified depth. Do not damage reinforcing steel. If more than one half of the diameter of the reinforcing bar is exposed and the bar is corroded around the circumference, adjacent concrete is rust stained, or the bar is debonded from the substrate concrete, c hip away concrete or water blast to provide a minimum clearance of 3/4 in. or
1.5 times the largest size aggregate in the repair material . Stop and recalibrate machine when depth of
removal or surface roughness is different from that approved. Cold planing or milling operations before hydro- demolition will be subsidiary to hydro- demolition. At minimum, hydro- demolition will be no less than 3/4 in. unless otherwise shown on the plans.
3.3 Shot Blasting . Demonstrate shot blasting on test areas as specified to cal ibrate machine to obtain depth of
surface removal required and to obtain finish as specified and as approved. Do not alter grade or cross slope unless shown otherwise. Maintain and adjust machine calibration to produce surfacing required.
3.4 Diamond Grinding. Demonstrate diamond grinding on specified area and obtain approval of finish
produced. Perform grinding in longitudinal direction. Grind surfaces on both sides of transverse joints to be flush (same elevation). Eliminate minor depressions by extr a grinding as directed. Produce a uniform surface with a longitudinal corduroy -type texture that eliminates joint and crack faults. Maintain transverse cross -slope to provide drainage across surface. 756 Repeat grinding until surface grade and cross-slope satisfy ride requirements. Minimum ride requirements are 1/4 in. in 10 ft. unless shown otherwise.
3.5 Saw Grooving. Cut grooves into concrete surface parallel to the structure centerline. Cut grooves across the
slab to within 18 in. of the barrier rail, curb, or median divider. At skewed metal expansion joints in bridge slabs, adjust groove cutting by using narrow width cutting heads so all grooves end within 6 in. of the joint, measured perpendicular to the centerline of the metal joint. Leave no ungrooved surface wider than 6 in. adjacent to either side of the joint. Cut grooves continuously across construction joints or other joints in the concrete less than 1/2 in. wide. Apply the same procedure described above where barrier rails, curbs, or median dividers are not parallel to the structure centerline to maintain the 18- in. maximum dimension from the end of the grooves to the gutter line. Cut grooves continuously across formed concrete joints.
Article 4 — Measurement
This Item will be measured by the square yard of concrete bridge deck surfaced.
Article 5 — Payment
The work performed and equipment furnished in accordance with this Item and measured as provided under “Measurement” will be paid for at the unit price bid for “ Micro Milling Concrete Slab” to the depth required, “Hydro- Demolition” to the depth required, “Shot Blasting,” “Diamond Grinding Slab,” and “Saw Grooving.” This price is full compensation for removing all material to the depths shown; preparing the surface; texturing the surface; saw grooving the surface; loading, hauling, unloading, and disposing of the cuttings; protection of drains, property, and traffic; disposal of water and runoff; and equipment, labor, tools, and incidentals.