- 557 - SECTION 710 -- CONCRETE BRI DGE DECK REPAIR WITH CLASS 47BD 4000 CONCRETE
710.01 Description
1.The work shall include removing unsound concrete, disposing of the old concrete, preparation of the r epair area, and furnishing, placing, finishing, and curing the concrete for repairs to bridge deck.
710.02 Material Requirements
1.Materials shall conform to the requirements in Table 710.01. Table 710.01 Material Requirements Applicable Materials Section Portland Cement Concrete ............................ .1002 Curing Ma terials ............................................. .1010, 1011 Fine Aggregate for Concrete Bridge Deck Overlays ......................................................... . 1033 Coarse Aggregate for Concrete Bridge Deck Over lays................................................ . Water for Concrete ......................................... .1005 Adhesiv e ........................................................ .1018 Joint Sealing Filler .......................................... .1014
2.The 47BD concrete may use Class F coarse aggregate shown in Table 1033.03A.
710.03 Equipment
1.Surface preparation equipment shall be of the following types:
a.Concrete saws capable of sawing to a specified depth.
b.Sandblasting equipment able to remove rust and concrete from exposed reinforcing bars. The equipment shall also be able to remove loose and fractured particles from the prepared concrete surface.
c.Power-driven hand tools will be allowed with the following restrictions:
1.Jackhammers greater than the nominal 60 lb (27 kg) class shall not be used.
2.Jackhammers or chipping tools shall not be operated at an angle greater than 45 degrees measured from the deck surface.
3.Chipping hammers greater than the 30 lb (13.5 kg) class shall not be used to remove concrete from beneath reinforcing bars in partial depth repair.
2.Vibrating screeds, either mech anical or hand operated shall be used to finish the concrete.
710.04 Construction Methods
1.General Requirements:
a.No loads other than construction equipment shall be allowed on any portion of the concrete de ck which has undergone preparation and removal of the old concrete surface. No construction load will be allowed which exceeds either an 8,000 lb (3625 kg) wheel load or a 16,000 lb Concrete Bridge Deck Repair
710.04 with Class 47BD 4000 Concrete
- 558 - (7250 kg) axle load. Any combination of axles closer than 4 feet (1.2 m) center-to-center will be considered to be one axle.
b.The Contractor shall take al l necessary precautions to prevent damage to persons or proper ty beneath the structure.
2.Concrete Removal Requirements: a. When no overlay is indicate d on the plan, the Contractor shall use a diamond blade to cut around the perimeter of the repair area to a depth of one inch. All repairs shall be cut so the edges are parallel or perpendicular to the traveled way. Wh en an overlay is indicated on the plan, saw-cutting is not necessary and edges shall be left irregular.
b.The Contractor shall remove, scarify or chip the concrete deck to a minimum depth of two inches and until all unsound concrete is removed. Where scarifying equipment cannot be used, hand chipping will be required.
1.Care shall be exercised to prevent cutting or otherwise damaging any exposed reinforcing bars. Repairs to damaged reinforcing steel shall be performed at no expense to the Department. Additional concrete removal and replacement necessary to repair damaged reinforcing steel shall be at no expense to the Department.
2.Any damaged epoxy coating of existing reinforcing steel shall be repaired according to Subsection 1021.03.
c.Removal work is divided into two classes according to the depth of material removed:
1.Partial Depth Repair - co vers concrete removal from the deck surface to the mid-depth of the slab.
2.Full Depth Repair - covers concrete removal depths from the lower limit for Partial Depth Repair through the entire remaining deck.
d.Partial Depth Repair: (1) Where machine scarifying is employed to remove concrete, extreme care shall be used to avoid cutting reinforcing bars. Any damage caused by the Contractor shal l be repaired by the Contractor as directed by the Engineer at no additional cost to the Department.
2.At points where removal of unsound concrete is adjacent to reinforcing bars or the removal of unsound concrete leaves over 2/3 of the bar diameter exposed, the removal shall be continued to at least 3/4 inch (19 mm) below the bar that will allow ne w concrete to bond to the entire periphery of the exposed bar.
e.Full Depth Repair: (1) Wherever removal of unsound concrete extends to the top of the bottom layer of steel, the rema ining thickness shall be removed to the full depth of the slab; and such areas of removal shall be classified as "Full Depth Repair".
2.When concrete removal is at approximately mid-depth of the slab, the Engineer shall determine if the concrete quality and structural integrity of the remaining thick ness requires full depth removal. Concrete Bridge Deck Repair with Class 47BD 4000 Concrete 710.04 - 559 - (3) Any removals shall be carefully done to prevent damage to the bottom of the slab and to leave removal boundaries which will allow complete filling with plastic concrete.
3.Preparation of the Surface:
a.The Contractor shall sandblast and clean all exposed reinforcing bars, all prepared concrete surfaces, and the portion of the bridge curb and all surfaces of steel roadway joints which will be in contact with the concrete.
b.In cases where the placement of the concrete is delayed beyond 24 hours after the sand blasting has been completed, the formation of incidental rust on the rebars due to humidity or rain shall not be cause for re-sand blasting.
c.All debris and rubble resulting from deck removal shall be thoroughly swept up and disposed.
4.Forming: a. Forms shall be provided in areas of Full Depth Repair requiring full depth slab replacement. Forms for small areas (1 square yard [meter] or less) may be wired to the reinforcing bars for support. Forms for larger areas shall be supported by blocking from the beams.
5.Placing Concrete: a. The clean dry vertical and ho rizontal faces of the repair shall be coated with Grade 2 Epoxy Adhesive from the Department’s Approved Products List just before placing the new concrete.
1.The epoxy adhesive shall be applied to the vertical sides of the repair with a brush.
2.The epoxy application rate shall be limited so the epoxy adhesive does not become dry before it is covered with the new concrete.
b.The Contractor shall furnish and place Class 47BD 4000 psi concrete for the deck repair. The concrete shall be handled and consolidated so there will be no separation of the aggregate and the mortar.
c.An internal vibrator shall be used to consolidate the concrete. Excessive vibration shall be avoided.
d.A vibrating screed shall be used on repairs 5 foot or wider to finish the concrete to the final elevation.
e.The surface shall be floated with a magnesium bull float. The surface shall be hand tined parallel to the existing tining in the deck. If the deck is to be overlayed prior to opening to traffic, no tining is required.
6.Sealing Joints: a. All transverse and longitudinal joints surrounding the repair shall be sealed and the work considered subsidiary to the Partial or Full Depth Repair.
b.Sealing is not required if the repairs will be overlaid with asphalt or concrete. Concrete Bridge Deck Repair
710.04 with Class 47BD 4000 Concrete
- 560 - 7. Curing:
a.The Contractor shall apply curing compound to all concrete deck repairs.
b.The application rate shall be 1 Gal/200 SF (0.2 L/m2).
8.Smoothness: a. The elevation of deck repair s shall be corrected in a manner that eliminates swales or bumps. Sw ales and bumps are defined as having 1/8 inch or greater deviation usi ng an approved 10 foot straightedge. Corrective actions shall be completed by diamond grinding or replacement. The condition of the adjacent pavement shall be considered when evaluating the 1/8 inch deviation requirement.
710.05 Method of Measurement
1."Bridge Deck Repair, Partial Depth", and "Bridge Deck Repair, Full Depth" will be measured for payment by the square yards (square meters) of deck area repaired in accordance with each classification, as determined by field measurements.
710.06 Basis of Payment
1.P a y I t e m P a y U n i t Bridge Deck Repair, Partial Depth Square Yard (SY) [Square Meter (m2)] Bridge Deck Repair, Full Depth Square Yard (SY) [Square Meter (m2)]
2."Bridge Deck Repair, Partial Depth", and "Bridge Deck Repair, Full Depth” will be full compensation for all work specified in this Section including all sawing, removing, forming, sandblasting, concrete and materials used for the repair.
3.Payment is full compensation for all work described in this Section. - 561 - SECTION 711 -- CONCRETE BRI DGE DECK REPAIR AND OVERLAY
711.01 Description
1.This work shall consist of the removal of the existing deck surfacing, resurfacing with class 47B-O L concrete, and other incidental work as shown in the contract.
2.A pre-placement conference at a time mutually agreed upon shall be held before the initial placement of Class 47B-OL concrete. Representatives of the admixture manu facturers, the concrete producer, the Contractor, and Materials and Research shall meet with the Engineer to discuss the following:
a.Mix proportions. b. Batching sequence. c. Batch size.
d.Work schedule.
e.Applicable specif ications and special notes.
f.All equipment that will be used. g. Delivery details. h. Special training for finishers. i. Duties of all personnel.
j.Overlay construction details.
k.Testing requirements. l. Acceptance criteria. m. Contingency plans. n. Methods of measurements. o. Basis of payment.
711.02 Material Requirements
1.Materials shall conform to the requirements in Table 711.01. Table 711.01 Material Requirements Applicable Materials Section Portland Cement Concrete ..................... 1002 Curing Material s ...................................... 1010, 1011 Sand and Gravel Aggregate .................. 1033 Ledge Rock Aggr egate ........................... 1033 Water for Concrete .................................. 1005
2.Ledge Rock aggregate for use in Class 47B-OL concrete shall be uniformly saturated with water before it is used. The wetting shall begin 24 hours before concrete mixing to allow complete saturation.
711.03 Equipment
1.Machines with oil leaks or drips shall not be used on the prepared deck surface.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 591–594 of 1,048.